13th Dayton Engineering
Sciences Symposium

List of Submitted Abstracts

* Note that appearance on this list does not guarantee that the abstract has been or will be accepted. All submitted abstracts will be reviewed for suitability and technical content.

Oral Presentations

Design & Optimization

Abstract ID: DESS2017-015

Satellite articulation characterization from an image trajectory matrix using optimization

David Curtis
Air Force Institute of Technology
Richard Cobb
Air Force Institute of Technology

Autonomous on-orbit satellite servicing and inspection benefits from an inspector satellite that can autonomously gain as much information as possible about the primary satellite. This includes performance of articulated objects such as solar arrays, antennas, and sensors. This paper presents a method of characterizing the articulation of a satellite using resolved monocular imagery. A simulated point cloud representing a nominal satellite with articulating solar panels and a complex articulating appendage is developed and projected to the image coordinates that would be seen from an inspector following a given inspection route. A method is developed to analyze the resulting image trajectory matrix. The developed method takes advantage of the fact that the route of the inspector satellite is known to assist in the segmentation of the points into different rigid bodies, the creation of the 3D point cloud, and the identification of the articulation parameters. Once the point cloud and the articulation parameters are calculated, they can be compared to the known truth. The error in the calculated point cloud is determined as well as the difference between the true workspace of the satellite and the calculated workspace. These metrics can be used to compare the quality of various inspection routes for characterizing the satellite and its articulation.

Abstract ID: DESS2017-021

Design Optimizattion of a Heavy Lift SUAS

Justin Ouwerkerk
University of Cincinnati
Dr. Kelly Cohen
University of Cincinnati
Dr. Manish Kumar
University of Cincinnati
Bryan Brown
University of Cincinnati

As the UAS industry continues to grow, a niche for platforms with a legitimate payload and endurance has been growing even faster. Currently, most heavy lift UAS are quite large and cost an exorbitant amount, these specialty platforms are designed with one specific operation in mind. Most commercially available platforms specialize in industries such as photography, videography, mapping, and agriculture; these platforms often cost ten of thousands of dollars. These lack the capability to re-purposed as useful, unique, research platforms and are too large to be considered for indoor use in combination with prevailing research. As such, the need for a small heavy lift endurance platform has grown within the research community; one which allows for an actual payload, sans batteries, making the platform feasible to accomplish tasks. This research will show the processes involved in the design, construction and operation of a Small Unmanned Aerial System (SUAS) for use in heavy lift, endurance and autonomous applications. Using lessons learned from prior research with large platforms, a small, under 1m, frame was constructed using a combination of off the shelf and custom fabricated components. This custom, heavy lift SUAS platform will fly for 30 minutes, and will be robust enough to be easily reconfigurable for a variety of different mission parameters, all while maintaining a practical and usable payload.

Abstract ID: DESS2017-031

Autonomous Vehicle Task Selection Under Operational Constraints

Christopher Olsen
Air Force Institute of Technology
Dr. Donald L. Kunz
Air Force Institute of Technology

The Persistent Intelligence, Surveillance, and Reconnaissance (PISR) problem seeks to provide timely collection and delivery of data from a set of prioritized geographic points of interest using an autonomous Unmanned Aerial System (UAS). In the literature, this problem is related to a class of Vehicle Routing Problems (VRPs) known by many names including persistent monitoring, persistent surveillance, and patrolling. The objective is to minimize the maximal weighted revisit time to each task, where the task's revisit time increases proportionally with time, scaled according to its weight, or priority. In order for an autonomous agent to perform PISR, it must implement a method of task selection. We propose the Maximal Distance Discounted & Weighted Revisit Period (MD2WRP) utility function as a solution. We have already demonstrated that, performance-wise, MD2WRP is competitive with Traveling Salesman approaches to PISR as well as with other utility-function methods from the literature, while offering several advantages that make it attractive for use in a dynamic mission environment. In our current work, we analyze the performance of MD2WRP under several operational factors: Dubins' constraints on vehicle motion, the presence of no-fly zones (keep-in/keep-out), and return-to-base constraints. Our current challenge is to develop a simulation environment capable of handling such constraints and then to compare agent behavior and performance under those constraints with our previous results, which assumed Euclidean motion and no operational constraints.

Abstract ID: DESS2017-053

Metamodeling for Effectiveness Based Design of an Aircraft with Uncertainty

Daniel Clark
Wright State University
Harok Bae
Wright State University
Darcy Allison, Edward Alyanak, and Edwin Forster
Air Force Research Laboratory

Awaiting public release.

Abstract ID: DESS2017-059

Analysis of Cube Satellite Formations

Robert Larue
Air Force Institute of Technology
Kirk Johnson
Air Force Institute of Technology

This study will examine the formation establishment and control problem for an Earth-orbiting CubeSat formation. The proposed formation will consist of three CubeSats in a circular, sun-synchronous reference orbit. Guidance and control algorithms will be developed that establish a desired formation based on the initial states of the spacecraft, simulating dispersal from a launch vehicle. A formation-keeping strategy will be developed that minimizes life-cycle delta-V in the presence of J2 perturbations. The effectiveness of the algorithms will be evaluated by a numerical simulation of the establishment trajectories and assessing the accuracy (desired geometry) and efficiency (fuel cost) of the solution. The resulting algorithms will provide fuel-optimal formation establishment trajectories and formation-keeping maneuvers. The effect of satellite initial states on life-cycle delta-V and formation quality will be assessed. The goal is to provide an analysis that quantifies the performance of a CubeSat formation over the course of its life-cycle.

Abstract ID: DESS2017-060

Linear Modeling of an Electromechanical Actuator Test Rig

Jeremiah Hoffman
Air Force Institute of Technology
Dr. Anthony Palazotto
Air Force Institute of Technology
Dr. Nicholas Niedbalski
Air Force Research Laboratory

Traditional aircraft design has utilized hydraulic control surface actuation, but interest in and use of electro-mechanical actuator (EMA) systems is growing. In light of this development, and in view of the various challenges associated with EMA systems, the Air Force Research Laboratory has built a passive electro-mechanical actuation test (PEMAT) facility, designed for use in exploring dual EMA parallel configuration force-fight characteristics. The PEMAT facility was not designed with the goal of representing a specific actuator system, design, or application, but rather to utilize simple input functions to easily analyze force-fight conditions, with development of detection and mitigation schemes for a variety of EMAs in mind. It would be useful, however, if the PEMAT facility could be used to simulate the conditions a real actuation system could experience, allowing for the evaluation of existing EMA suitability or development of requirements for new EMA characteristics for use in various control system architectures: such is the focus of this research. In order to determine the above, there are several steps we seek to accomplish: first, the development of an accurate first-order model of the PEMAT facility. Since the test rig load profile is manipulated via torsional spring deflection and adjustable inertia, the representation can only extend to the first order (i.e., load vs deflection), and it is to this fidelity that we seek to model. The second step is the use of this model in developing time-dependent position functions which result in load profiles representative of the conditions an actuator could experience in a given flight mode. The final step would be validation of these position functions in the PEMAT facility: if the facility can reproduce the load profile with acceptable accuracy and error characteristics, it could be useful in initial performance analysis and requirements generation for a variety of EMA systems.

Abstract ID: DESS2017-061

Femtosecond vs Nanosecond Laser-Induced-Breakdown Stability Analysis

Anil Patnaik
Spectral Energies LLC
Paul Hsu, Sukesh Roy
Spectral Energies LLC
James R. Gord
Air Force Research Laboratory
Adam Stolt, Jordi Estevadeordal
North Dakota State University

In a recent study, nanosecond-laser–based LIBS was employed for quantitative local fuel to air (F/A) ratio measurements in well-characterized methane-air flames at pressures of 1 – 11 bar. Nitrogen and hydrogen atomic-emission lines at 568 nm and 656 nm, respectively, were selected to establish a correlation between the line intensities and the F/A ratio. From the detailed parametric study, it was observed that ns-LIBS shows very high instability in F/A ratio measurement at high pressures. The correlated measurements of LIBS and electron number showed that the short-ps to long-fs excitations are expected to reduce the instability in F/A ratio measurements at high pressure. For this presentation, we present recently concluded fs-LIBS and ns-LIBS measurements of the nitrogen gas in a high-pressure gas cell. Our initial results are very promising in terms of significantly reduced noise in fs-LIBS compared to the ns-LIBS measurements performed in the same conditions. These measurements will be extended to high-pressure burner in near future.

Abstract ID: DESS2017-064

Power/Thermal Interaction within an Adaptive Turbine Engine

Andrew Desomma
Wright State University
Dr. Mitch Wolff, Dr. Rory Roberts
Wright State University

Historically engine power take off (PTO) for two spool turbofan engines has been done via the high pressure (HP) shaft and bleed air from the high pressure compressor (HPC). This power is used to run various aircraft components such as generators and hydraulic pumps which concurrently also produce waste heat that needs to be rejected. This method of PTO is not necessarily the optimal method of extracting power off of an engine. To better understand the highly coupled transient nature of the balance of thrust, power take off and waste heat injection, a transient variable cycle three stream turbofan engine was developed in Simulink® as a tool to investigate new solutions to this problem. This model incorporates many dynamic features including a third-stream heat exchanger to act as a heat sink for aircraft thermal systems and power take off to simulate the shaft loads of components. This presentation describes a method of controlling HPC surge margin while extracting power using both the high pressure and low pressure spools while maintaining desired thrust. This allows for greater amounts of power extraction then what was allowed by other methods. This presentation will investigate their transient interaction as both power take off and 3rd stream heat rejection are simultaneously applied to the transient engine model. This will be accomplished by assuming various efficiencies and system delays.

Abstract ID: DESS2017-073

Fuel Optimal, Finite Thrust Guidance Methods to Circumnavigate with Lighting Constraints

Eric Prince
Air Force Institute of Technology
Richard Cobb
Air Force Institute of Technology

This presentation details improvements made to the authors' most recent work to find fuel optimal, finite-thrust guidance to inject an inspector satellite into a prescribed natural motion circumnavigation (NMC) orbit about a resident space object (RSO) in geosynchronous orbit (GEO). Better initial guess methodologies are developed for the low-fidelity model nonlinear programming problem (NLP) solver to include using Clohessy-Wiltshire (CW) targeting, a modified particle swarm optimization (PSO), and MATLAB's genetic algorithm (GA). These initial guess solutions may then be fed into the NLP solver as an initial guess, where a different NLP solver, IPOPT, is used. Celestial lighting constraints are taken into account in addition to the sunlight constraint, ensuring that the resulting NMC also adheres to Moon and Earth lighting constraints. The guidance is initially calculated given a fixed final time, and then solutions are also calculated for fixed final times before and after the original fixed final time, allowing mission planners to choose the lowest-cost solution in the resulting range which satisfies all constraints. The developed algorithms provide computationally fast and highly reliable methods for determining fuel optimal guidance for NMC injections while also adhering to multiple lighting constraints.

Abstract ID: DESS2017-074

Design Optimization of Transient Systems

Alexander Henz
Wright State University
Rory Roberts
Wright State University
Mitch Wolff
Wright State University

System integration and design is typically a steady-state driven process during the conceptual design stage. Steady-state optimization provides a single solution to provided operating conditions. Oftentimes, multiple operating conditions are considered during this process for compliance of operation. In this traditional design method, the transition between each of the operating points is not considered, omitting potentially crucial information within the system response. With increased interest in more electric systems in the aerospace and automotive industries, it becomes necessary to include the transient response during the conceptual design phase to ensure the desired operation and performance is achieved. Modeling and analyzing the transient responses of systems requires the inclusion and development of controls. Controls are often specific to a specific configuration and sizing of a system. Poorly selected controls can mislead the design process by hindering system performance. It is necessary to automatically develop or eliminate controls during the conceptual design process. A tool for transient design optimization of thermal management systems is currently in development using MATLAB® and Simulink®. The methodology used to create this tool addresses the challenge of controls development during the conceptual phase by determining the optimal time-dependent path of operation for a given system. This new tool and methodology for transient analysis allows for the potential to rapidly analyze and evaluate system responses during the conceptual design process while also providing insight into the development of controls.

Abstract ID: DESS2017-075

Optimal Path Planning for SUAS Waypoint Following in Urban Environments

Michael Zollars
Air Force Institute of Technology
Richard G. Cobb
Air Force Institute of Technology
David J. Grymin
Air Force Research Laboratory

In this research, Small Unmanned Aircraft Systems (SUAS) are used to determine feasible flight paths to multiple waypoints within an urban environment. Direct orthogonal collocation methods are used while leveraging navigation mesh techniques developed for fast geometric path planning solutions. Waypoints are included throughout a constrained city map to illustrate feasible flight paths through tightly constrained path corridors. The two-dimensional solution is achieved in a multi-phase approach defined through a discretized simplex mesh with aircraft control on acceleration and the change in the vehicle's heading rate. Constrained optimal control problems for SUAS have long suffered from excessive computation times caused by a combination of constraint modeling techniques and the quality of the initial path solution provided to the optimal control solver, ultimately preventing implementation into real-time, on-board systems. These issues are addressed by triangulating the search space to define a polygonal search corridor free of constraints while alleviating the dependency of defining problem specific parameters in the optimal control software. Utilizing algorithms developed for geometric path planning, the initial path solution is comprised of four path intervals connecting each waypoint. These path intervals provide a constraint free search corridor defining a search domain for the optimal control software. Results are applied to illustrate two-dimensional flight trajectories through downtown Chicago at an altitude of 550 feet Above Ground Level (AGL).

Abstract ID: DESS2017-077

Model-Based Systems Engineering and Aerospace Conceptual Design

Brendan Rooney
Air Force Research Laboratory

The purpose of this presentation is to explain the benefits of combining Model Based System Engineering (MBSE) methods and the Aerospace Conceptual Design process. MBSE is a formal modeling process used for system requirements, design, analysis, verification and validation activities. The discussion explains the object-oriented nature of Aerospace systems and how the design process should reflect this. Traditional Systems Architecting and traditional Aerospace Conceptual Design often times communicate over a brick wall. This brief will discuss how MBSE can be used in Aerospace Conceptual Design to overcome this barrier.

Abstract ID: DESS2017-079

A Cellworks Method for Structural Shape and Topology Optimization

Hao Li
Wright State University
Dr. Ramana V. Grandhi
Wright State University

In the typical structural design process, there is a major gap in the number and types of configurations that are available between the conceptual and detailed design phases. This research proposes a new framework which facilitates a large number of configurations by performing shape and topology optimizations simultaneously during early stages of design. Cellular division method with a level-set based optimization is proposed. Cellular-division based design methodology is an innovative biologically-inspired layout and topology optimization method aimed to generate unconventional structural configurations by global design space exploration. A multi-objective genetic algorithm is used to mimic the process of how the nature develops the best designs. A typical drawback of such method is that the shape changes are based on the mechanics of the cellular dynamics in living organisms, but not the physical behavior of engineering systems, which results in sub-optima and low convergence rates. Level-set method designs the structural boundary implicitly and evolves based on the system behavior to handle designs with complicated shape changes, but it has high dependency on its initial design choices. In this research, level-set based shape optimization method is integrated to optimize initial topology generated by cellular division module. The new methodology is demonstrated on benchmark structural stiffness design problems to show the advantages over the traditional cellular division and level-set methods.

Abstract ID: DESS2017-081

Space-based Maneuver Detection using Multiple Model Adaptive Estimation

Justin Katzovitz
Air Force Institute of Technology
Dr. Joshuah Hess
Air Force Institute of Technology

An increasingly congested space environment requires current and dynamics space situational awareness on all objects in Earth's orbit. Current statistical orbit determination techniques can effectively and efficiently predict and track the orbits of space debris and planned maneuvers of cooperative space assets. However, a non-cooperative spacecraft maneuvering at unknown times with unknown thrust profiles degrades the accuracy of traditional orbit estimators through unexpected changes in the predicted dynamical model. This study assesses the detection of non-cooperative spacecraft maneuvers with space-based measurements using multiple model adaptive estimation. An interacting multiple model framework coupled with a band of variable state dimension filters is implemented, tested, and compared to traditional orbit determination techniques through realistic maneuver detection scenarios using relative spacecraft orbit dynamics. A variety of sensor suites are used to prove the efficacy of the algorithm in a relative satellite reference frame. The algorithm performance is assessed through a series of Monte Carlo simulations with variable levels of measurement noise, data availability, and thrust profiles. The new techniques implemented are significantly more accurate in non-cooperative spacecraft maneuver detection when compared to other non-adaptive estimation methods. Analysis from this study will also make recommendations for transitioning this algorithm from academia to operational use in support of improving space-based space situational awareness for the United States Air Force.

Abstract ID: DESS2017-083

Bio-Inspired Optimization of the Traveling Salesman Problem

Jutshi Agarwal
University of Cincinnati
John McClellan
Reading Community High School
Ryan Wright
Ryle High School
Jeffrey Kastner
University of Cincinnati
Kelly Cohen
University of Cincinnati

Genetic algorithms apply biological concepts to a guided programming search technique for intelligent systems. One such problem that can make use of such a tool is the Travelling Salesman Problem (TSP). The TSP is an NP-hard problem in combinatorial optimization, making it an ideal problem to be tackled with AI systems. Traditionally, AI systems have used 2-opt algorithms or genetic algorithms to solve the TSP. By combining a 2-opt approach with the genetic algorithms, new, more optimal ways to tackle this problem may become more evident. Various methods for combining these two separate strategies were tested over a course of several weeks using MATLAB to find an ideal combination of the two. These iterations were tested for their ability to find an optimal solution to the TSP and narrowed down over time based on their performance. Each iteration was subjected to find the best value of the fitness function in an acceptable amount of the expense function. In the case of the TSP, the fitness function is the total distance traveled by the salesman on a closed route that is from one city to another and ending at the starting city. The expense function here is the computational time required by the algorithm and trade-offs are made to find a heuristic solution in an acceptable amount of time. TSP solutions were calculated using a 2-opt approach, a genetic algorithm, and a combination of the two algorithms. The GA was optimized at each stage of natural selection, mutation, and migration using a trial-and-error iteration for percentages of population sizes and length of chromosomal cross-overs. Eventually, a hybrid algorithm utilizing principles of a genetic algorithm and of a 2-opt method induced at the migration stage of the GA was implemented and found to outperform all previous iterations. The hybrid algorithm outperformed both the unhybridized genetic algorithm (with a random migrative addition) and 2-opt methods in terms of route distance. To provide a scope of multiple salesmen scenario, a k-means clustering function was implemented to split the route into three shorter closed routes, each then subjected to the hybrid algorithm. This further improved performance in terms of distances produced and computational time. Each algorithm was run for a specified set of 10-cities, 50-cities, and 100-cities. Algorithms were also tested against each other for a 1000-cities problem and results compared where acceptable computational times could be obtained. Comparative results and validation of the research have been presented thus proving the possibilities of using hybrid evolutionary algorithm to find the perfect solutions to other NP-hard problems.

Abstract ID: DESS2017-084

Parameter Study of Orbit Debris Defender Using Three Player Differential Game Theory

David Spendel
Air Force Institute of Technology
Joshuah Hess
Air Force Institute of Technology

The Air Force’s presence in space provides it with unparalleled persistent and global coverage. However, many of the Air Force’s systems were designed decades ago, without consideration for the congested environment. Additionally, collision avoidance maneuvers significantly reduce the lifespan of satellites by expending station keeping fuel. This study assesses the viability of an orbit debris defender that mitigates debris concerns, on behalf of a maneuvering evader. In order to capture the worst case scenario, the debris is assumed to be an optimally behaving pursuer. A two team, three player pursuit evasion game is the basis for the simulation, known as ‘The Lady, The Bandit and the Bodyguard’. This research created a simulation framework and then analyzed the simulation results for a variety of different initial conditions. The research provides a new way to solve the three player game, while not assigning control laws to either team such as a linear regulator or proportional navigation. Analysis from this study will provide the framework for the design of the orbit defender.

Engineering Education

Abstract ID: DESS2017-017

McCook Aviation Engineering STEM challenge

Wayne Lundberg
Air Force Life Cycle Management Center

The Centennial of Aeronautical Engineering in the US has increased awareness of aircraft engineering in Dayton area. The Wright-Patterson Educational Outreach office challenged schools and educators in the region to include aircraft design in their curriculum by providing a tether-plane for aerodynamic design experimentation. The Aviation STEM activity required only that the Junior and Senior High School teams use the electric motors provided and a similar power supply. They redesigned wings, fuselage and tail sections to maximize cargo lift. The McCook Centennial called for a schedule that proved difficult to integrate into a school science syllabus. The tether-plane also proved to have its own technical challenges, since a tethered object obeys laws of motion distinct from that of a free-flight airplane. While this was evident early on, it created opportunities for design changes that were not easily anticipated. The correct equations describing aerodynamic lift and tether tension were formulated.

Abstract ID: DESS2017-050

Using Model Solar Boats to Provide a Continuous Renewable Energy Education from Middle School to the University

Tim Dewhurst
Cedarville University

Practical, hands-on experience is a powerful tool for teaching engineering concepts. However, hands-on projects that do not demonstrate the mathematical basis for sound engineering designs limit the students’ understanding of engineering. Cedarville University has been competing in solar-boat racing for 20 years, both in the United States and Europe. A major component of Cedarville’s success has been the development of good mathematical models for each system in the boat (e.g. hull, solar system, motors, propellers, etc.). We are able to use these models to improve the design until a world-class boat is created. When are K-12 students ready to see that engineering involves the development of a good system of mathematical equations that model the real world, and that engineering designs can be created by optimization of these models? When will they see that there is a use for the complex mathematics they are learning? In conjunction with Solar Splash, the Intercollegiate World Championship of Solar/Electric Boating, we are developing the Jr. Nautical Solar Challenge for middle school students. In 2017, at the Solar Splash event (with funding from ASME Dayton Section), we inaugurated this competition and helped children to build these boats on site to teach concepts about solar energy and renewable resources. However, in building and racing the boats in one day, we were not able to demonstrate the mathematical modeling, which is very important to the field of engineering. During the 2016-2017 academic year, we are looking to expand this program to several STEM programs in middle schools in the Dayton-Springfield region. The focus of this program is to teach the students several concepts concerning: • Renewable energy • Mathematical modeling of physical systems • Hull construction techniques • Electric motor principles • System integration • System optimization • Craftsmanship. By taking more time than a one-day event, we hope to be able to couple mathematical modeling with hands-on construction. In middle school and high school, students learn mathematics often without an end-goal in view. This project looks to improve the hands-on experience by demonstrating the strong connection between mathematics and engineering design. Discussions are underway with a number of local STEM schools to take this solar boat challenge to the next level. The plan is to finalize the curriculum be the end of 2017, and implement the program in the spring of 2018. Races will be held at individual schools, and the best boats from the various schools will be invited to compete in the championship at the Solar Splash event in June 2018 at the Clark County Fairgrounds in Springfield, Ohio.

Abstract ID: DESS2017-096

Neuroprosthetic Hands - A Focus on Feedback

Evan Helton
Wright State University

Neural prostheses are a series of devices that can substitute a motor, sensory or cognitive modality that might have been damaged as a result of an injury or a disease. The brain-machine interface (BMI) used in neural prosthetic hands involves recording signals from neuron populations, decoding those signals using mathematical modeling algorithms, and translating the intended action into physical limb movement. Recently, somatosensory feedback has become the focus of many research groups given its ability in increased neural control by the patient and to provide a more natural sensation for the prosthetics. This process involves recording data from force sensitive locations on the prosthetics and encoding these signals to be sent to the brain in the form of electrical stimulation. Tactile sensation has been achieved through peripheral nerve stimulation and direct stimulation of the somatosensory cortex using intracortical microstimulation (ICMS). The objective of this project is to, based on the current stage of research in the tactile feedback of neurological prosthetic hands, determine the most feasible and economical design for a robotic prosthetic hand device that best allows the user to perform essential tasks.

Fluid Dynamics / CFD

Abstract ID: DESS2017-002

Unsteady Endwall Flow Measurements in a Front Loaded Low Pressure Turbine Passage

Emma Veley
Air Force Research Laboratory
Chistopher Marks
Air Force Research Laboratory
Rolf Sondergaard
Air Force Research Laboratory
Mitch Wolff
Wright State University

The flow field at the junction of a highly loaded low pressure turbine blade and endwall is comprised of complex three-dimensional flow structures. Time resolved measurement of these near wall flow features in a turbine passage is challenging because the data-taking instrumentation alters the flow field. Measurements using thin-film sensors on the endwall through a high lift low pressure turbine passage were compared with an implicit large eddy simulation. The thin-film probe was installed on the endwall at the passage vortex with and without an adjacent hotwire sensor. The frequency spectra from numerical simulation compared well with the thin-film and hotwire. An effect of the hotwire on the flow measurement was observed reinforcing the advantage of using a non-intrusive surface mounted thin film sensor. The thin-film sensor enables time resolved near wall flow measurements on LPT passage surfaces which provides insight into the unsteady behavior of endwall flow structures.

Abstract ID: DESS2017-008

The investigation of flexible trailing edge fringes on the wake of an airfoil S833

Hongtao Yu
Wright State University
Zhengkai He
Wright State University
Zifeng Yang
Wright State University

A S833 airfoil equipped with a flexible fringe at the trailing edge has been investigated using computational fluid dynamics (CFD) simulations. The influence of the fringe length and flapping frequency on shedding vortices has been studied. Numerical simulations on the vortex characteristics in the wake of the airfoil were conducted by using the CFD software Cradle SC/Tetra as the 2D incompressible flow solver.. The simulation results of vorticity distributions in the flow field revealed that the model with the fringe length of 10% of the chord length and the flapping frequency of 110 Hz could reduce the strength of the shedding vortex to altering extents, contributing more irregular vortices with a smaller size in scale and a shorter distance between each pair of vortices. In the meantime, the flexible trailing edge fringe with a low flapping frequency could aid to break the routine large-scale vortex into small-scale weak vortices, and as a results, to accelerate the dissipation of vorticity. The equipped trailing edge fringe can also achieve the reduction of the drag and the enhancement of lift coefficients, which are the additional benefits from this technology.

Abstract ID: DESS2017-019

Lift and Drag Coefficient Studies for the NACA 0012 and the NREL S829 Airfoils

Barathkumar Mohanarangan
Wright State University
Dr. James Menart
Wright State University

Lift and drag coefficients of the symmetrical NACA 0012 airfoil at a Reynolds number of 1.5 million and the semi-symmetrical NREL S829 airfoil at a Reynolds number of 1 million are calculated using the computational fluid dynamics software ANSYS Fluent. The NREL S829 airfoil was designed for use on wind turbines. This airfoil has a thickness that is 16% of the chord length and a maximum camber line that is 0.7% of the chord length. In this work, the Reynolds-averaged Navier-Stokes equations are solved in conjunction with a two equation, k-ω turbulence model using appropriate boundary conditions far away from the airfoil and no slip boundary conditions on the airfoil. Detailed calculations are carried out for angles of attack from -15 to +15 degrees for both these airfoils. Comparisons to results published in the literature and those produced by the computer program QBlade are made. In addition to lift and drag results, pressure and velocity field results will be presented.

Abstract ID: DESS2017-022

Grid Independence in Large Eddy Simulations of a Premixed Bluff-Body Flame

Joshua Sykes
Innovative Scientific Solutions Inc.
Christopher A. Fugger
Spectral Energies LLC
Andrew W. Caswell, Brent A. Rankin
Air Force Research Laboratory

A wide variety of combusting systems use bluff bodies to anchor flames, making bluff-body cases valuable candidates for evaluating large eddy simulation (LES) chemistry models. Of specific interest is the ability to numerically capture near-limit phenomena such as lean blowout and thermo-acoustic combustion instabilities. In this presentation, meshes of varying periodic domains and cell sizes are used within a variable-density low-Mach number LES solver (VIDA) with flamelet progress variable (FPV) closure to study the behavior of an enclosed equilateral triangle flameholder. Grid independence is considered for both reacting and non-reacting flows, with the observation that independence in the reacting cases is much more difficult to achieve. However, mesh clustering in the flow boundary layers is shown to reduce the overall cell count necessary for independence. Finally, the effect of velocity inlet profiles are considered. It is demonstrated that in the reacting cases the flowfield sensitivity to the velocity profile is significantly reduced.

Abstract ID: DESS2017-032

Three-dimensional temperature measurements in a turbulent flame

Benjamin Halls
Air Force Research Laboratory
Paul S. Hsu, Naibo Jiang, Ethan S. Legge, Sukesh Roy
Spectral Energies LLC
Terrence R. Meyer
Purdue University
James R. Gord
Air Force Research Laboratory

Awaiting public approval.

Abstract ID: DESS2017-044

Characterization of a Toroidal Jet Stirred Reactor Using Hot-Wire Anemometry

Robert Stachler
University of Dayton
Joshua Heyne
University of Dayton
Scott Stouffer
University of Dayton Research Institute
Joseph Miller
Air Force Research Laboratory

Abstract awaiting public release

Abstract ID: DESS2017-045

Suppression of Vortex-Induced Vibration of an Elliptical Cross Section Using Convective Heat Transfer

Jeffrey Desroches
Air Force Institute of Technology
Dr. Anthony Palazotto
Air Force Institute of Technology
Dr. Hui Wan
Air Force Research Laboratory

The reduction of vortex-induced vibration of a two-dimensional cylinder and other elliptical cross sections can be achieved using convective heat transfer. This study uses computational fluid dynamics to model a cross section that is elastically mounted and heated. The flow direction is aligned with the direction of the thermal induced buoyancy force and the body is allowed to translate perpendicular to the flow. The amplitude of the vibrations can be reduced as the thermal control parameter Richardson number (Ri) increases. The vibration can be fully suppressed when Ri is above a critical value. The critical Ri is found to be dependent on shape, Reynolds number, and the mounting stiffness. In addition, drag is studied as a function of Ri. For a body with particular mounting stiffness parameters, drag is reduced until the Richardson number reaches the critical value, where the drag is at a minimum.

Abstract ID: DESS2017-051

Physics of Impinging Liquid Jets: Primary and Secondary Atomization

Prashant Khare
University of Cincinnati

Liquid jets and droplets play a vital role in numerous applications of practical interest including, liquid-fueled combustion devices such as diesel, gas-turbine and rocket engines, cooling of turbine blades and microchips, and industrial processes such as spray painting and inkjet printing. Even after decades of research, because of the lack of appropriate diagnostic and simulation tools, the understanding of atomization process remains limited. Further, no attempts were made in the past to conduct fundamental studies that led to the development of universal theories and models to predict statistics, such as, droplet/particles sizes and distributions, resulting from the fragmentation process. As a consequence, much of the existing knowledge and many of the design tools for analyzing primary and secondary atomization are, thus, empirically based and established through time-consuming and costly processes of trial and error. Therefore, this talk focuses on two aspects of the atomization process, (1) identification of mechanisms and processes underlying the dynamic behaviors of impinging liquid jets; and (2) investigation of fundamental physics of the deformation and fragmentation of droplets, and development of generalized models to predict the characteristics of resulting droplet distributions. The theoretical and mathematical formulation to investigate these two-phase problems is based on three-dimensional incompressible Navier-Stokes equations with surface tension. A critical issue is the treatment of multi-scale liquid-liquid and gas-liquid interfaces. A state-of-the-art, high resolution, volume-of-fluid (VOF) interface capturing method is adopted to resolve the interfacial evolution. Surface tension is accommodated as a Dirac delta distribution function on the interface. The theoretical formulation outlined above is solved numerically using a finite volume method augmented by an adaptive mesh refinement (AMR) technique, based on an octree spatial discretization to improve the solution accuracy and efficiency. Based on the high-fidelity direct numerical simulations, general theories that quantitatively describe the atomization process over a wide range of operating conditions are established. These theories are used to develop universal models that can predict the droplet behaviors, including size-distributions and drag coefficients with deformation and fragmentation. The ultimate goal of the effort is to enhance the fundamental understanding of multiphase flows, and to develop theories, models and algorithms for their active and passive control.

Abstract ID: DESS2017-052

Comparative Analysis: Low-Fidelity and High-Fidelity Hypersonic CFD

Jose Camberos
Air Force Research Laboratory
Farrell Hohman
Air Force Research Laboratory

Accurate yet timely solutions from CFD solvers are fundamental in creating databases of aerodynamic responses for future trajectory simulations of hypersonic vehicles. This comparative analysis focuses on three CFD solvers of varying levels of fidelity and assesses the tradeoff between the speed and accuracy of their computations for hypersonic flow with the given assumptions that each program makes. The nature of each solver indicated that the highest fidelity program would yield the most accurate solutions, however, the work was towards evaluating where the low-fidelity solver began to stray from the accepted values of the high-fidelity calculations. Cases were run at a range of low to high Mach numbers and at numerous degrees of angle of attack to ultimately indicate that the low-fidelity solver converges to solutions similar to the high-fidelity results but these values fall off in accuracy at a lower Mach range that has been closely examined. With the results of this analysis and further study, lower fidelity solvers can be used for models in the development phase or for cases that need rapid solving.

Abstract ID: DESS2017-055

Experimental Investigation of Endwall Flow Control for Front Loaded Turbine Blades

Nathan Fletcher
Wright State University
Mitch Wolff
Wright State University
Christopher R. Marks
Air Force Research Laboratory
Ryan Petrie
Air Force Research Laboratory
Rolf Sondergaard
Air Force Research Laboratory

One focus of recent research on low-pressure turbines has been directed towards reducing size, weight, and part count while maintaining performance. Gains in these turbine characteristics can be made by increasing the aerodynamic loading on the low-pressure turbine airfoils. However, the increased loading on these blades can cause 3-D aerodynamic losses near the endwall to increase. The current presentation involved a front-loaded blade geometry which is characterized by good midspan performance but suffers from higher secondary losses near the endwall. Three-dimensional vortical flow structures near the endwall contribute to losses and this research sought to mitigate the effects of these flow structures through active flow control using steady and unsteady blowing. The experimental results obtained show significant loss reduction when blowing air. Comparisons involving various blowing ratios and blowing frequencies were analyzed in order to find optimal configurations.

Abstract ID: DESS2017-057

Unsteadiness and Modal Decomposition of Scramjet Unstart Computations

Logan Riley
The Ohio State University
Jeffrey M. Donbar
Air Force Research Laboratory
Mark A. Hagenmaier
Air Force Research Laboratory
Datta V. Gaitonde
The Ohio State University

A clear understanding of the complex phenomena resulting in unstart can greatly facilitate improved prediction of such events and guide the development of procedures to mitigate loss of control authority. In the present work, we apply model-order reduction (MOR) techniques, specifically snapshot-based Proper Orthogonal Decomposition (POD) and Dynamic Mode Decomposition (DMD), to simulations of scramjet unstart with the objective of evaluating their ability to extract dynamical features which may facilitate the development of a reduced-order model (ROM). The computational dataset, previously validated with experiments, was generated from unsteady Reynolds-Averaged Navier-Stokes (URANS) of an ethylene-fueled scramjet featuring a rectangular isolator and combustor in the presence of inlet distortion. The relevant dynamical features are defined in terms of several quantitative measures of the velocity field and wall pressures. The ability to capture these features via MOR methods is assessed in the context of the unique unstart process, which is non-stationary in time. Scale-resolving computations such as Large-Eddy Simulations where POD have typically been leveraged are statistically-stationary in time. However, the non-stationarity of the unstart process presents challenges in the application of POD, because of the lack of a well defined time-mean. To address this issue, the transient data is windowed to isolate particular phases of the unstart process. DMD modes, in contrast, are ranked by dynamic behavior in time and may therefore extract features which POD might otherwise overlook. Despite the differences between these methods, transient features related to side-wall separation and the pre-combustion shock-train are identified in both.

Abstract ID: DESS2017-068

Effects of Fan Blade Blending on Unsteady Aerodynamics

Clint Knapke
Air Force Research Laboratory

Waiting for public release

Abstract ID: DESS2017-076

Non-Axisymmetric Endwall Contouring for the L2F

Jacob Dickel
Air Force Research Laboratory
Christopher R. Marks
Air Force Research Laboratory
John Clark
Air Force Research Laboratory
Rolf Sondergaard
Air Force Research Laboratory
Mitch Wolff
Wright State University

Various approaches have been used to shape the geometry at the endwall and blade profile in order to reduce the endwall losses in a high lift low pressure turbine blade row. This presentation will detail the design of a non-axisymmetric endwall contour for the front loaded L2F research profile. The L2F has excellent midspan Reynolds lapse performance, but a high generation of endwall losses. Various wall shaping functions are being evaluated in order to develop a smooth contoured shape across the endwall. A turbine design and analysis framework with tools for geometry manipulation, optimization, and post-processing will be used to develop the endwall shape. The AeroDynamic Solutions RANS flow solver LEO will be used to develop numerical models of each configuration. Modeling of the L2F blade passage using LEO has shown excellent agreement of total pressure loss and endwall flow structure compared with linear cascade measurements.

Abstract ID: DESS2017-090

Investigation of Near Wake Turbulent Fluctuations and its Relation to Wing Performance

Steven Goodman
University of Dayton
Sidaard Gunasekaran
University of Dayton

Maximum performance (L/D)max of an airfoil and is achieved only at certain initial conditions (angle of attack, freestream velocity, etc). Current experimental investigation is aimed at understanding the relationship between the turbulent behavior of near wake of SD7003 wall-to-wall model and its aerodynamic efficiency. Particle Image Velocimetry (PIV) was performed in the near wake of a wall-to-wall SD7003 wing for angles of attack ranging from -2 to 8 degrees at the AFRL’s Horizontal Free-Surface Water Tunnel (HFWT). Sensitivity analysis was performed to determine the effect of freestream turbulence in the PIV data through various filtering techniques. The overall objective is to compare the near wake data and the far wake data to determine any possible correlations with the aerodynamic efficiency. Understanding these correlations could lead to several implications such as better performance, attenuating unsteady aerodynamic loads and energy harvesting.

Heat Transfer / Thermal Sciences

Abstract ID: DESS2017-004

Tracking a Nonlinear Melt Region Produced During High Velocity Event

Armando Deleon
Air Force Institute of Technology
Dr. William Baker
Air Force Institute of Technology
Dr. Anthony Palazotto
Air Force Institute of Technology

The solution discussed in this paper relates to the high speed movement of a vehicle along a rigid support in which friction becomes a heat energy source for melt. The solution to the problem is through a one dimensional nonlinear heat transfer set of equations dependent upon vertical forcing function, created by horizontal movement characterized by velocity, that considers the hypersonic regime. A good example of this type of condition occurs within the USAF Holloman High Speed Test Track (HHSTT) at Alamogordo New Mexico. The HHSTT supports experiments which routinely test at hypersonic speeds. Modeling the entire test run would be computationally expensive due to thermal-mechanical coupling and non-linearities in geometry as well as material. This work utilizes a finite difference scheme to solve the one dimensional heat transfer equation while accounting for the differing pressures experienced by the slipper as it travels down the track.

Abstract ID: DESS2017-026

Modeling and Characterizing Wood Stove Efficiencies in Natural Draft and Induced Turbulent Environments

Sari Mira
University of Dayton
Joshua Heyne, PhD.
University of Dayton

Wood is one of the most used biomass energy resource in the world. Yet, wood combustion remains highly unoptimized due to the inherent complexity of the process. The wood combustion process is multidimensional and multiphase, leading to large uncertainties. In addition, Deficient mixing leads to incomplete combustion resulting in the production of toxic emissions such as CO, Polycyclic Aromatic Hydrocarbons (PAHs), and SOOT. In this research, effects of inlet parameters, various geometries, and experimental practice on wood stove combustion and thermal efficiencies for 4 types of stoves are examined. The initial phase of the research focuses on studying the effects in a natural draft environment. The latter phase of the research explores methods of improving the combustion and thermal efficiencies. Particularly, methods that are traditionally used in gas turbines. The three methods examined here are: 1) turbulence induction through pressure drop, 2) combustion chamber liner cooling, and 3) recirculation of the flame for better fuel and oxidizer mixing. For brevity, the combination of the three methods is referred to in this research as TCR – Turbulence, Cooling, Recirculation. The goal of this research is to study the factors that potentially reduce emissions and increase efficiency. A previous study by Hsu et al. (Hsu, Goss, Trump, Roquemore, 1998) has shown a positive correlation between induced pressure drop, due to induced turbulence, and primary equivalence ratios in the combustion region. This correlation provides an opportunity to utilize the dynamics of a trapped vortex to manipulate the scale in which chemical kinetics occur to be smaller than the Kolmogrov scale; creating turbulent fuel and oxidizer mixing eddies in the reaction region of the flame. Preliminary results of the natural draft experiments showed that a traditional 3-stone stove, which is typically 10-15% efficient, is in fact capable of achieving thermal efficiencies as high as 30% given the correct experimental practice. This sensitivity has also been observed in the other stove types. The second phase of the research has been initiated with the hypothesis of thermal and combustion efficiency improvements when applying the TCR methods.

Abstract ID: DESS2017-034

Preferential Vaporization's Effect on Lean Blow Off

David Bell
University of Dayton
Joshua Heyne
University of Dayton

As the number of jet fuel feedstocks continues to expand with the addition of alternative fuels, it becomes increasingly important to quickly and accurately predict combustion performance of new fuels. Gas turbine engine combustion involves both spraying and reaction of fuels, which complicates the problem as both physical and chemical effects could be present. Presently, there is experimental data suggesting a correlation between cetane number and lean blow out, however this correlation fails noticeably specifically on surrogate fuel blends and binary component mixtures. One possible explanation for these outliers is preferential vaporization. Looking at the cetane number of the vaporized liquid 20% through the distillation process improved the correlation and reduced the outliers. In this research, preferential vaporization’s impact is explored and a new fuel blend is proposed to stress test this hypothesis.

Abstract ID: DESS2017-054

A Cryogenic Palletized High Energy Pulse System

Nathan Butt
Wright State University
Rory Roberts
Wright State University
Witch Wolff
Wright State University

Effective cooling of thermal loads generated by High Energy Pulse Systems (HEPS) is becoming increasingly challenging as these loads grow larger with the development of new technologies. Advanced technologies are smaller and lighter, making the task of thermal management even more difficult. This is due to the fact that legacy cooling systems (circulating fuel) are limited by both fuel temperature and volume. In order for a legacy system to successfully cool a large heat load, the amount of the fuel and the fuel flowrate required becomes exorbitantly high. Vehicles such as aircraft with large thermal loads have an obvious weight restriction, so another method of cooling is required for successful vehicle operation. Therefore, utilizing a cryogenic based system is an attractive option. With cryogenics (like Liquefied Natural Gas), there exists a very high temperature difference between the cryogenic cooling fluid and the component to be cooled. This enables significantly more heat to be managed than with legacy systems. A Simulink model has been developed to simulate cryogenic cooling of large thermal loads. If the approach is actually a viable solution to this problem this could radically change the method by which thermal loads are managed. The proposed cryogenic thermal management system is compared to a legacy thermal management system. This provides a clear understanding of how the cryogenic and traditional systems perform when compared to each other.

Abstract ID: DESS2017-078

Rapid Response Temperature Control of High-Heat Flux Loads

Andrew Ellicott
Wright State University
Dr. Mitch Wolff
Wright State University
Dr. Rory Roberts
Wright State University

Aircraft are increasingly carrying high-power density electronic devices, which are not continuously operated. Such devices require cooling for effective operation, however large continuous-operation cooling systems are not energy or weight efficient. A rapid response, high heat flux temperature control system is being developed utilizing an actively controlled two-phase fluid. The instability of the fluid phase transition is utilized to achieve high-frequency operation. The system will first be modeled with a transient physics-based model and a transient benchtop experimental testbed will be used to acquire data. The model fidelity will be improved by the experimental data and the improved model will be used to determine the feasibility of a conceptual aviation-class cooling system.

Abstract ID: DESS2017-062

High-Temperature Fuel Cells in Hypersonic Applications

Jack Chalker
Wright State University
Rory Roberts
Wright State University
Mitch Wolff
Wright State University
Scott Thomas
Wright State University
Praveen Cheekatamarla
Antrex Energy

Awaiting Public Release.

Abstract ID: DESS2017-066

Experimental Study of Centrifugally-Loaded Backward-Facing Step Burner Dynamics

Tim Erdmann
Innovative Scientific Solutions Inc.
Andrew W. Caswell, Brent A Rankin
Air Force Research Laboratory
Ephraim Gutmark
University of Cincinnati

Awaiting Public Release

Abstract ID: DESS2017-067

A new experimental test bed for cavity-stabilized reacting flows

Kyle B. Brady
National Research Council
Brent A. Rankin
Air Force Research Laboratory
Andrew W. Caswell
Air Force Research Laboratory

Abstract awaiting public release.

Abstract ID: DESS2017-086

Transient Thermal Management System for High-Heat Flux Loads

Stephen Shock
Wright State University
Dr. Rory Roberts
Wright State University
Dr. Mitch Wolff
Wright State University

In aerospace applications, electronic devices produce high-heat flux loads during operation while having to be maintained within a specific temperature range. These devices do not operate with a continuous heat load; thus, traditional cooling systems made to handle large heat loads are not feasible for this type of application. A transient thermal management system is being modeled with the application of two-phase fluid cooling. The two-phase fluid allows for rapid changes in cooling due to the instability of the fluid. An experiment will then be developed on a tabletop test area to evaluate and obtain real data. The experimental data will be used to improve the initial model’s accuracy. The combination of the experimental data and improved numerical modeling will allow for further development of thermal management approaches for dynamic heat fluxes in aerospace applications.

Human Factors / Biomedical

Abstract ID: DESS2017-014

Development and Evaluation of a SmartWalker Posture Monitor

Jack Schultz
University of Dayton

Over 6.1 million Americans use walkers and other walking aids. These aids enable continued independence and community participation despite the onset of mobility deficits due to aging or disease. Research has shown, however, that many users exhibit a high percentage of improper walker use, most notably a forward leaning posture during ambulation which appears to relate to a higher fall incidence among older adults. For the past few months, we have been involved in the design and evaluation of an electro-mechanical system that monitors a user’s posture and provides real-time visual feedback cues in an effort to improve posture when using the walker. The system has been designed with a sensor that detects linear relative distance from the user’s trunk (directed at the midsection) to the attachment point on the walker (varies depending on the type of assistive device). The device then provides a visual cue, in the form of different colored lights, to inform the user of their current posture, and an indication of how to improve. Initial testing of seven individuals to obtain feedback and development ideas has suggested a few key areas where the design could be improved. This led to the development of an improved prototype which is now undergoing user testing involving an Xsens system, a 3D motion tracking software. Our results to date support the assumed need of the technology, as well as the potential for improving not only the user’s safety while walking, but also their overall quality of life.

Abstract ID: DESS2017-058

Laser Biofeedback for Improving Lower Extremity Motor Control

Luke Schepers
University of Dayton
Bridget Dues
University of Dayton
Kayla Kress
University of Dayton
Dr. Megan Reissman
University of Dayton
Dr. Kimberly Bigelow
University of Dayton

Movement disorders of the lower extremities are common for many individuals who have experienced neurological conditions including stroke and multiple sclerosis. Multiple studies have shown that individuals have increased mobility or motor control function after receiving some form of corrective visual feedback during rehabilitation or training. Recently, a wearable laser light system that provides real-time visible feedback on movements has emerged as a commercially available rehabilitation tool. The purpose of our study is to determine if the use of a limb mounted laser light, worn during a leg raise task, can improve kinematic performance and reduce pathologic frontal plane motion. The study has recruited participants with diagnosis of stroke and multiple sclerosis resulting in decreased lower extremity motor control in one or both lower limbs. Participants complete a series of clinical tests to examine how clinical measures relate to performance response. The study focuses on two lower limb tasks: a box step-up task and a maximum knee raise task. During each task full body motion capture and force plate data is collected to evaluate the participant performance. Both of the tasks are performed three times; first without the laser turned off (baseline), second with the laser turned on, and lastly with the laser turned off to examine after-effects. For both tasks we will examine maximum excursion of the center of mass and center of pressure, temporal metrics, and kinematic metrics of maximum frontal and sagittal plane lower limb angles. Results will be statistically analyzed using a repeated measures analysis of variance (ANOVA) model. Preliminary results indicate that, when performing the max knee raise, a pilot stroke subject showed increased max hip flexion and max knee flexion while the laser was in use and following laser use, as compared to baseline. The subject also spent a greater amount of time completing the exercises while the laser was in use as compared to baseline. This suggests that when the laser feedback is given, subjects are able to make a positive change in increasing their maximum kinematic motion, and are willing to spend a longer time on the exercise which could enhance their single limb balance capabilities. Other parameters are being evaluated to assess the rehabilitative value of the laser biofeedback in regards to hip abduction and frontal pelvis angle.

Abstract ID: DESS2017-080

Moving Towards Tuning of Ankle-Foot Orthoses (AFOs): The Influence of Carbon and Plastic AFOs for Individuals with Multiple Sclerosis

Sarah Hollis
University of Dayton
Kayla Kress
University of Dayton
Dr. Kimberly Bigelow
University of Dayton
Dr. Kurt Jackson
University of Dayton

Mobility impairments are reported as the most debilitating symptoms for individuals with Multiple Sclerosis (MS), a neurological disorder where the body’s immune system attacks the central nervous system (CNS) damaging the nerves and myelin surrounding them. Balance and gait impairments, as well as muscle weakness and sensory deficits are some of the most common symptoms of MS. Fatigue management is another common symptom, which can further affect the mobility of these individuals. Ankle-foot orthoses (AFOs) are one potential solution to alleviate some of these mobility impairments. AFOs commonly are prescribed to aid in increased toe clearance and support during swing stages of the gait cycle, force management during heel strike, and energy storage. However, the effectiveness of AFOs for individuals with MS are currently inconclusive and have known downfalls. We took a comprehensive look at both carbon fiber and polypropylene AFOs to gain an understanding of the immediate effects of AFOs for individuals with MS. In collaboration with the University of Dayton’s Doctorate of Physical Therapy Program, data was collected for 9 participants on various balance, gait, and strength/fatigue assessments. Each participant came in for a total of three visits to complete the assessments under baseline with no AFO, carbon, and polypropylene conditions. Overall, no significant differences existed between the three AFO conditions for any assessment outcome (p>0.05); however trends did arise within the static and dynamic balance tasks. Other measures from the gait and strength/fatigue assessments were varied among each participant including their personal preferences. Most individuals preferred the carbon AFO, however some did prefer the polypropylene. These results suggest the importance of considering individual responses and patient preferences when prescribing AFOs. For this study, all AFOs were off-the-shelf with only slight adjustments to account for fit and alleviate any pain; however, a process called AFO tuning is believed to help optimize the efficiency of AFOs. AFO tuning, or customizing, is done by adjusting the angle of the shank during mid-stance and the stiffness of the footplate to help support the individual throughout the gait cycle. The next step in this work is to investigate the effects of AFO tuning in collaboration with area clinical partners. A case study is currently underway to give insight and better understanding to the effects of AFO tuning for individuals with neurological disorders.

Abstract ID: DESS2017-091

Smart Materials for Prosthetic Sockets

Wendy Fisher
Wright State University
Dr. Tarun Goswami
Wright State University

Approximately 185,000 people per year in the U.S. undergo an amputation and the total number of amputees is estimated to go up to 2.2 million amputees by 2020. The most common complaints from amputee patients include sweating, temperature, and pressure points within the prosthetic socket. There are also smart materials that exist that can sense and react to changes in the environment, such as humidity, temperature, and pressure. The objective of this project is to combine these current smart material technologies with prosthetic sockets to solve some of these problems. If smart materials are integrated into prosthetic sockets, the component that tends to wear out the fastest, this could prolong the life of the socket, and therefore cut down the overall cost for patients.

Abstract ID: DESS2017-093

Passive Above Knee Prosthetic Kinematics Improvement

Michael Collier
Wright State University

Most above the knee prosthetics have artificial knee joints that are sturdy and inexpensive. Most of them are also incapable of keeping pace with the remainder of an amputee’s residual limb, forcing the amputee to adopt an unnatural gait. There are, however, highly advanced, motorized prosthetics that use micro-processors and sensors to keep up. Unfortunately these active prosthetics are exceedingly expensive, costing tens of thousands of dollars. To this end, multiple groups are attempting to produce above the knee prosthetics that are fully passive, yet still keep up with a patient’s residual limb. This includes a knee joint made with a gear and another that using locking and dampening mechanisms to allow the prosthetic to keep up with its wearer. This report will analysis the kinematics of these prosthetics (and wearer) and the forces they are subjected to. It will also examine advantages and shortcomings of these devices, along with possible improvements to future models. Adviser: Dr. Goswami

Abstract ID: DESS2017-094

Energy Efficiently Of Hand Prosthetics

Stephen Whatley
Wright State University

One of the largest problems facing the design of prosthetics is how effectively they use energy. This is especially true for newer powered prosthetics. These modern day prosthetics have more in common with computers and they need energy to both think and move. Like any smart device, a powered prosthetic is no good when the battery is dead, and it is because of this it is imperative that they use the energy they have with the upmost efficiency. This project takes a look into how hand prosthetics are powered and how efficiently the components of the prosthetic use that energy.

Abstract ID: DESS2017-095

Combining Pressure-Sensing Materials With Adjustability to Optimize Prosthetic Socket Fit

John Inkrott
Wright State University

Socket fitting for a prosthetic leg is an ongoing problem in the prosthetics industry. Fitting a patient correctly, and maintaining that fit, is critical to the functionality and efficiency of a prosthetic leg. There are currently a number of sockets available on the market with a high amount of adjustability, but no feedback to guide the adjustments. In addition, there are currently pressure-sensing sockets on the market, but none with adequate adjustability to allow a patient or prosthetist to make adjustments to create an adequate fit. This project will focus on combining pressure-sensing sockets with adjustability to allow for continuous adjustment by the patient to optimize socket fit, functionality, and efficiency.

Abstract ID: DESS2017-097

Design and Optimization of Lower Limb Prosthesis

Anmar Salih
Wright State University
Dr. Tarun Goswami
Wright State University

In the United States, there are approximately two million people living with limb loss. It is estimated that one out of every 200 people in the U.S. has had an amputation. In 2009, hospital costs associated with amputation totaled more than $8.3 billion. Every year, most of the causes of the amputations occur due to the complications of the vascular system, from diabetes to be specific. This type of amputation is known as dysvascular. In addition to the dysvascular, there is a high rate of amputations from cancer and trauma, however, the number of dysvascular amputations are on the rise. The purpose of this project is to study the pros and cons of the current designs and investigate the possibilities to optimize the current lower limbs prosthetic systems. The results showed that the best stress distribution was when the material is carbon fibers. Also, the modified socket model showed a significant decrease in the maximum stresses than the current designs. In conclusion, the results showed a substantial need to optimize the current socket models to overcome the limitations to be more suitable for patients.

Abstract ID: DESS2017-098

Design Optimization of an Additve Manufactured Prosthetic Foot

Paul Ley
Wright State University
Dr. Tarun Goswami
Wright State University

Over 113,000 lower limb amputations occur annually. Historically a large portion of these amputees are diabetic, and up to 55 percent of diabetics with one lower extremity amputation will require a second amputation within three years. Unfortunately for amputees, contemporary prosthetics can be costly, excessive in weight, and often lack customizable designs. Additive manufacturing a plastic prosthetic device is proposed to eliminate these issues. The goal of this project is to determine the feasibility of manufacturing a functional, k-2 to k-3 activity level, printed prosthetic foot. The final prototype needs to be adaptable to current cosmetic foot shells and lower limb connectors; it must cost under $4,000, and be capable of withstanding 300 pounds of force. Optimally the design should also have a fatigue life cycle of two years, weigh less than current prosthetics, and be customizable to the individual user. Exploring the efficacy of the design, use of finite element analysis will simulate ISO standardized testing methods, comparing results with the ISO requirements. With the completion of these tests and interpretation of the accumulated data will report the completeness and feasibility of the designed prosthetic.

Abstract ID: DESS2017-099

Sensing Materials for Prosthetic Sockets

Rachel Hatridge
Wright State University

The most critical aspect of any prosthesis is the quality of the interface between the residual limb and the artificial prosthesis. The socket determines the amputee's comfort and ability to control the artificial limb. Current problems with prosthetic sockets include poor stump-socket fitting due to short residual limbs and residual limb volume changes, friction leading to the development of pressure sores infection of the stump soft tissues, sweating often leading to limb disuse, durability, and increased energy expenditure by the amputee. The goal of this project is to explore new and recent materials that are capable of sensing and correcting issues with temperature, pressure, and volume change within the prosthetic socket.

Abstract ID: DESS2017-100

Controlling lower limb socket temperature

Juan Maldonado
Wright State University
Adviser- Dr. Goswami
Wright State University

The constant humidity and temperature inside a lower limb prosthetic socket is an actual problem for amputees. Rise in the temperature and humidity increase the chance of ulcerations because of the medium of friction inside the liners. Adding a ventilation artifact would be a good option to reduce this problem. Socket material and Liner (impact comfort, minimize friction forces, and provide even pressure distribution) modifications would help to provide a better ventilated area.

Abstract ID: DESS2017-102

Adult Bracing and Orthotics

Lazette Carter
Wright State University

Looking into the aid of upper limbs with braces and/or canes. Using these devices can become challenging and wear on the surrounding, undamaged joints and muscles. Walking braces can be made up of frames (rigid, folding, reciprocal, forearm supporting, and wheeled) and crutches (forearm, axillary, gutter, walking sticks, and tripods/tetrapods). Using most arm crutches with your whole weight on the crutch tops will eventually result in peripheral nerve damage. According to The Amputee Coalition, they are also harder on the shoulders and inclined to make you hunch over, creating bad posture and sore backs. The type of grips on that style of crutch can eventually produce carpal tunnel syndrome. However, if the handles, support pads and walking tips would adjust to the user’s pressure and walking terrain, the crutch would cause less damage in the future. Those with prosthetics can use crutches in addition for at least part of the rehabilitation process.

Abstract ID: DESS2017-104

Quantified Self: Variation of Spirometer Readings in Relation to Varied Activity Levels, Asthma Medication, and Age

Neeti Prasad
Dayton Regional STEM School

Quantified Self is a movement that uses technology to collect data about different aspects of daily life of a person in terms of their activity, environment, physiological parameters, etc. to enable “self-knowledge through self-tracking with technology”. Recently, there has been an increase in the use of wearable sensors and kHealth devices such as the Fitbit, iPhone, Apple Watch, Foobot, and Spirometer for various purposes ranging from monitoring our health and environment, to ease in network and communication. Asthma is a common chronic disease, which, according to CDC, afflicts 1 in every 13 people, and can be fatal. It is important for a patient to understand and detect the triggers that can worsen asthma-related symptoms to prevent another asthma attack and ensure timely treatment or rescue plan. Our goal in this project was to use different medical sensors and devices to better track the symptoms of an asthmatic patient and to correlate possible triggers in the patient’s daily activities to symptoms that patients experienced. We can then learn what conditions would cause an asthma attack and engage patients in their health care. To allow a patient to track their symptoms, daily activities, indoor, and outdoor air quality conditions, a team of students and faculty at Kno.e.sis Center, Wright State University developed the kHealth Kit. This kit includes a spirometer to track the Peak Expiratory Flow (PEF) and Forced Expiratory Volume, a Samsung tablet to track the symptoms and medication, a Fitbit to track physical activity, and a Foobot to measure indoor air condition such as pollen level, Air Quality Index (AQI), Particulate Matter (PM) and Volatile Organic Compounds (VOC), and similar outdoor parameters from public sources. We experimented with an asthmatic patient, collecting three weeks of data. For Set1 data, from April 19th- April 25th, we noted down the different sensor values while the patient was taking 2 puffs of Flovent morning and evening and was rowing regularly for 2 hours every day for six days a week. For Set2 data, collected from, May 15 - May 18, Flovent was stopped while still keeping the same activity level. For Set3 data, collected from May 22 – May 26, both Flovent and rowing were stopped. We also compared these spirometer values with a non-asthmatic patient’s spirometer values. Data analysis revealed that Set1 PEF values were much lower than Set2 PEF values. From Set3 data we found that having medication and being outside caused more symptoms than not having medication and being indoors. That is, the medication did not supersede the effect that the pollen had. On April 20th, the patient experienced chest tightness and took Ventolin (a rescue asthma medication). The PEF spirometer values were much lower than the typical values. The AQI, PM, pollen level, and VOC were higher than safe levels. Overall, this project showed that a patient can track different aspects of asthma, and reliably predict or diagnose their symptoms to manage their asthma, thereby reducing asthma-related doctor and ER visits.

Manufacturing

Abstract ID: DESS2017-003

Impact welding of dissimilar material combinations and of additively manufactured materials

Bert Liu
Air Force Institute of Technology
Anthony Palazotto
Air Force Institute of Technology
Anupam Vivek
The Ohio State University
Glenn S. Daehn
The Ohio State University

Vaporizing foil actuator (VFA) is a novel tool for impulse-based metal working operations. It has been used for impact welding of aluminum flyer sheets to high-strength steel and magnesium plates. Aluminum alloy 6061 sheets of 0.81 mm thickness were launched to velocities in excess of 800m/s and found to weld to both the target materials investigated: HSLA A588 steel and AM60B magnesium alloy. Grooved as well as flat target plates were utilized. Welding with grooved target plates was found to be not very robust as the weld samples came apart during sectioning. However, the flat targets welded successfully, and during mechanical testing, failure was found to occur outside the joint. The weld interface morphology for each material system and configuration has been shown. Some improvements to the grooved-target experimental configuration are also demonstrated. Upcoming work will include additively manufactured materials and investigation of their high-strain-rate behaviors.

Abstract ID: DESS2017-024

Autonomous Controls in Industrial Energy Efficiency

Louis De Gruy
University of Dayton
Danny Ulbricht
University of Dayton
Zachary Siefker
University of Dayton

The University of Dayton Industrial Assessment Center (UD-IAC) has performed nearly 1,000 energy assessments for mid-sized manufacturing facilities throughout the Midwest. Over the past year, the UD-IAC identified an average of 20% potential energy savings per assessment. To do so, the UD-IAC utilizes a systematic approach for improving industrial energy efficiency that breaks down complicated manufacturing processes into distinct energy systems: electrical distribution, motor drive, lighting, fluid flow, compressed air, process heating, process cooling and space conditioning systems. Maximizing energy effectiveness and control in each of these energy systems successfully minimizes manufacturing energy consumption. The UD-IAC has found that recommendations improving equipment controls in each of these energy systems yields the most attractive savings opportunities due to the typically low implementation cost coupled with relatively high energy savings. Over the past year, the UD-IAC has offered over eighty energy-efficient controls recommendations with average annual savings of $20,000 and an average simple payback of 11 months. With increased access to data and reduced computing costs, autonomous equipment controls can be further developed to improve industrial energy efficiency. Future work in the UD-IAC, in addition to the energy assessments for manufacturers, seeks to investigate machine-learning algorithms to improve autonomous controls and the energy efficiency of industrial process equipment.

Abstract ID: DESS2017-036

Investigating the Biocompatibility of the Ti-6Al-4V Surface Machined by Electrical Discharge Machining

Md. Rashef Mahbub
Miami University
Roan Kirwin, Paul F. James, Muhammad P. Jahan
Miami University

Ti-6Al-4V, i.e. grade 5 titanium alloy, is extensively used as biomedical implants due to its high specific strength (strength-to-weight ratio), excellent mechanical and thermal properties, and outstanding corrosion resistance. The objective of this study is to investigate the biocompatibility of the machined surface of Ti-6Al-4V prepared by the electrical discharge machining (EDM) process. The biocompatibility of the machined Ti-6Al-4V samples with different levels of surface roughness were studied by conducting cell cultures and evaluating the proliferation and attachment of mouse osteoblastic cell MC3T3-E1 to the machined surfaces. For conducting cell culture experiments, Ti-6Al-4V discs of 7.5 mm diameter were machined using different levels of discharge energy settings using the wire-EDM (#1 roughest to #4 smoothest). For each machining conditions, three samples were prepared for cell cultures. In addition, one as-received conventionally machined surface (#0) and one tissue culture treated plastic surface (#TC) were used for comparison. The average surface roughness of different samples was measured and the surface topography was analyzed. It was found that MC3T3-E1 cells attached to all of the titanium samples surfaces, but to varying degrees for different levels of surface roughness. It was found that cell attachment/proliferation was reduced, when compared to TC, on Ti-6Al-4V discs with the roughest surfaces (conditions #1 and #2). On the other hand, cell attachment/proliferation increased with increasing smoothness of the surface (conditions #3 and #4). Under condition #4 (the smoothest of the EDM machined surfaces) the cell attachment/proliferation was essentially the same as the #TC sample surface. However, the non-EDMed surface (condition #0) which has a surface even smoother than condition four, also supported high attachment/proliferation but apparently at a lower level than condition #4. These experimental results support the idea that there remains an optimal surface roughness condition that promotes better cell adhesion, and the surface machined by EDM could promote improved cell adhesion compared to conventionally machined surface.

Abstract ID: DESS2017-037

Mechanical and Microstructural Characterization of Laminated Steel Structures made via Ultrasonic Additive Manufacturing

Tianyang Han
The Ohio State University
Dr. Leon Headings
The Ohio State University
Dr. Aslan Miriyev
Columbia University
Prof. Marcelo Dapino
The Ohio State University

Ultrasonic additive manufacturing (UAM) is a solid state manufacturing technology for producing metal parts combining additive ultrasonic metal welding and CNC subtractive machining. Even though UAM has been demonstrated to produce robust metal structures in Al-Al, Al-Ti, Al-steel, Cu-Cu, Al-Cu, and Al- NiTi material systems, UAM welding of high strength steels presents challenges. In this study, current progress on steel to steel welding via UAM is discussed. The effect of pre-heat temperature as a process parameter along with the influence of hot isostatic pressing (HIP) as a post process treatment on the UAM steel samples are discussed. Shear tests were performed to characterize the mechanical strength of UAM steel samples. Additionally, optical images and electron backscatter diffraction (EBSD) measurements are discussed.

Abstract ID: DESS2017-038

Investigating Tool Wear Mechanisms in Machining of Ti-6Al-4V Using Coolant, Dry and Minimum Quantity Lubrication (MQL) Conditions

Ashutosh Khatri
Miami University
Muhammad Jahan
Miami University

The objective of this study is to identify and explain the tool wear mechanisms that dominate during machining of titanium alloy Ti-6Al-4V in various machining conditions. In this context, milling machining was carried out on Ti-6Al-4V with three different conditions namely dry, flood coolant, and minimum quantity lubrication (MQL). The cutting feed rate and depth of cut were varied keeping the cutting speed constant, while uncoated and titanium aluminum nitride (TiAlN)-coated carbide tools were used for machining. It was observed that abrasion was the dominant tool wear mechanism for all dry, flood coolant and MQL machining, although MQL and flood coolant machining had fewer abrasion occurrences compared to dry machining. Edge chipping and tool nose wear were the second most dominated tool wear mechanisms in conventional flood coolant machining, which may be associated with the thermal fatigue caused by the sudden cooling of tool tip from the high temperature generated during machining. On the other hand, adhesion was the second dominant tool wear mechanism seen in the dry machining of titanium alloy. Both the edge chipping and adhesion of chips to the cutting tools were reduced significantly in MQL machining. Delamination of coating film was observed when TiAlN-coated carbide tools were used. The delamination was more significant in wet and MQL machining compared to dry machining, indicating the effectivity of coated tools in dry machining compared to wet and MQL machining. There were some cases of plastic failure of tool flutes and edges, with again dry and flood machining having more occurrences of tool failure than MQL. The abrasion wear was dominant on the rake and flank face of the cutting tools, whereas, the adhesion occurred mostly on the secondary cutting edge. The chipping was found in both primary secondary cutting edges. Among three conditions, MQL provided the least occurrences of tool wear, indicating suitability of MQL in productive machining titanium alloys.

Abstract ID: DESS2017-040

Investigating the Effect of Wire Feed Rate and Wire Tension on the Corner and Profile Accuracies During Wire-EDM of Ti-6Al- 4V

Roan Kirwin
Miami University
Md. Rashef Mahbub, and Muhammad P. Jahan
Miami University

Ti-6Al- 4V (grade 5 titanium alloy) is one of the most widely used materials in aerospace applications including turbine blades for aerospace engines. Due to the difficulty of machining titanium alloys using conventional machining processes, wire-electro- discharge machining (wire-EDM) is used extensively for cutting titanium parts with complex geometries and profiles. The objective of this study is to investigate the effect of two important non-electrical parameters in wire-EDM, i.e. wire feed rate and wire tension, on the geometric corner and profile accuracies of the Ti-6Al- 4V parts machined by wire EDM. A complex profile was designed for machining in two different thicknesses of titanium alloy using each set of experimental parameters. The complex part includes corners with 45 0 , 90 0 and120 0 , as well as thin wall section for measuring the kerf accuracy. It was found that with the increase of wire tension, the corner accuracies at almost all the angles improved. However, too high wire tension caused inaccuracies by providing larger angles than the target values. The effect of wire tension was dependent on the thickness of the machined part. For thinner workpiece the results of the angles generated barely followed a trend, whereas for thicker part, the measured angles followed an excellent trend. The kerf accuracies were found to improve with the increase of wire tension for thin part, whereas for thick part the results of kerf width accuracies were inconsistent. In case of wire feed rate, it was found that comparatively lower settings of wire feed rates were favorable for machining thinner parts with enhanced corner accuracies. On the other hand, slightly higher wire feed rates provided better corner accuracies for thick part. Besides corner inaccuracy, profile undercuts and deviations from the machining paths were observed for lower wire tensions. Finally, it can be concluded that comparatively lower wire feed rate and higher wire tension provides improved corner and profile accuracies. However, for machining thinner sections using wire-EDM, the trends are not obvious.

Abstract ID: DESS2017-047

Integration of aluminum and non-metals using ultrasonic additive manufacturing for structural reinforcement, joining, and electro-thermal tailoring

Leon Headings
The Ohio State University
M. Bryant Gingerich
The Ohio State University
Hongqi Guo
The Ohio State University
Yongsen Rong
The Ohio State University
Marcelo Dapino
The Ohio State University

Ultrasonic additive manufacturing (UAM) is a technology that utilizes ultrasonic metal welding to additively join thin metal foils to create 3D parts. The UAM process takes place without melting of the constituent metals which enables the seamless integration of a vast array of metallic and non-metallic materials. The UAM process can be used to embed fibers into metals, creating lightweight composites that do not require adhesives or mechanical fasteners. High strength fibers include carbon fiber, Zylon, and alumina, yielding components with high specific strength and toughness. In addition to embedding fibrous materials, UAM can be used to create laminated metal-ceramic structures for electrical and thermal insulation.

Abstract ID: DESS2017-041

Investigating Micro Scale Machinability of Polycarbonate Glass

Craig Hanson
Miami University
Muhammad P. Jahan
Miami University

Polycarbonate glass material has gained popularity because of its wide applications as optical lenses. Besides applications as lenses, polycarbonate glass is used in electronic, automotive, and aircraft industries because of its insulating, heat-resistant and flame-retardant properties. This study aims to investigate the micro scale machinability of polycarbonate glass in micro-milling process using uncoated and coated carbide tools. The effectivity of titanium nitride (TiN) and titanium aluminum nitride (TiAlN) coatings on the tungsten carbide tool for machining of polycarbonate glass was also investigated. The machinability was evaluated in terms of the cutting forces, tool wear, burr formation and the machined surface finish. It was found that the average cutting forces in Z direction, i.e. thrust force, increased in general with the increase of depth of cut and feed rate for both coated and uncoated carbide tools. However, the cutting forces in X and Y directions, i.e. radial cutting forces, were found to be lower at moderate feed rate rather than at too low feed rate. Among three cutting tools, TiAlN-coated tools generated the lowest cutting forces in all three axes. For surface finish, it was found that irrespective of tool coatings, there is a critical depth of cut that provided superior surface finish. It was found that a depth of cut of 0.3 – 0.4 mm provided improved surface finish in the micro-milling of polycarbonate glass. In case of burr formation, it was found that the burrs around the edges were reduced at increased feed rate for both coated and uncoated tools. The burr formation was higher at very low and high settings of depth of cut, and was found to be the lowest at the critical depth of cut. It was found that uncoated carbide tools produced least amount of burrs compared to TiN and TiAlN coated carbide tools. In case of tool wear, it was found that the tool wear increased with the increase of depth of cut and reduced first with the increase of feed rate and then again increased at very high feed rate. No significant differences in tool wear were observed between uncoated and coated carbide tools. In conclusion, by careful selection of optimum parameters and critical depth of cut, polycarbonate glass can be machined with improved surface finish and minimum burrs in micro-milling, irrespective of tool coatings.

Materials

Abstract ID: DESS2017-005

Two-dimensional nanoparticle array and cluster formation by supercritical fluid deposition

Joanna Wang
Air Force Research Laboratory
Gail Brown
Air Force Research Laboratory
Scott Apt
Air Force Research Laboratory
Chien Wai
University of Idaho

Nanoparticles (NPs) can be deposited as two-dimensional (2D) clusters into nanostructures of silicon substrate using supercritical fluid CO2 (sc-CO2) as the medium. Due to its unique properties including gas-like penetration, liquid-like solvation and near zero surface tension, sc-CO2 is capable of depositing NPs into nanometer-sized shallow wells which cannot be achieved by traditional solvent deposition methods. Nanoparticles tend to fill nano-structured shallow wells first, and then, if sufficient nanoparticles are available, they will continue to cover the flat areas nearby, unless defects or other surface imperfect areas are available. SEM images of two-dimensional gold (Au) nanoparticle arrays formed on silicon surface from 2 to a dozen or more of the Au nanoparticles are given to illustrate the patterns of nanoparticle array formation in sc-CO2. Formation of 2D NP arrays in large areas on silicon substrate surface is also described.

Abstract ID: DESS2017-049

Silica Nanosprings Used to Enhance Mechanical Properties of Carbon Composites

Tomasz Niedzwiecki
Miami University
Dr. Luigi Corti Calderon
Miami University

The increase in mechanical properties along with a decrease in weight has brought a growth of interest to advanced fiber composites from both the aerospace and automotive industries. Current methodologies for increasing interlaminar strength by increasing bonding area of composites include chemical functionalization and sewing through the laminates. This is both an expensive and time consuming processes. The present research introduces a new approach to circumvent the previous short fallings. By directly growing the silica nanosprings (SN) onto the carbon fiber layer; allows for the current micro and macro roughness to remain intact while introducing a nanoroughness and reactive surface for the resin to bind to. Nanosprings originating from neighbor surfaces will mechanically interact with each other in a similar fashion of two Velcro surfaces, thereby increasing the bonding interface performance and the whole strength of fiber metal laminates materials and fiber reinforced laminates. The 90 plus percentage of empty volume within the silica nanosprings and their natural interlocking structure creates a rebar-like scaffolding on the substrate, readily dispersing deformation energy throughout the fiber composite materials in a more efficient way. nanosprings increase the effective surface area for the substrate to bind to the matrix with a minimal increase in the overall weight of the material. Preliminary results of mechanical testing preformed on woven carbon fiber cloth have shown a significant increase in deformation energy with the nanospring coated samples will be presented.

Other

Abstract ID: DESS2017-009

Mousai: An Open Source Harmonic Balance Solver for Nonlinear Systems

Joseph Slater
Wright State University

Modern computational tools provide a plethora of numerical libraries for scientists and engineers. Packages such as BLAS (Basic Linear Algebra Subprograms), LAPACK (Linear Algebra PACKage), CLAPACK (C LAPACK), ScaLAPACK (distributed-memory LAPACK), PLASMA (Parallel Linear Algebra for Scalable Multi-core Architectures), MAGMA (Matrix Algebra on GPU and Multicore Architectures), QUADPACK (Numerical Integration), etc. form the foundation of scientific computing. They are available as libraries that can be accessed during compile of C, Fortran or other programs. More often they are interfaced every day by higher level scripting languages like Matlab, Python, R, Octave, etc. The linear algebra routines have made solution of massive linear models trivial. A student with Matlab can access the same tools that were a challenge for a researcher to access 30 years ago, irrespective of the change in speed of computers. Today users don’t think twice about solving eigenvalue problems that they may not fully understand. Users are mostly unaware of algorithms used in the solution. This enables them to focus less on the programming and more on obtaining solutions to the questions posed and the problems faced. What is lacking, however, is the nonlinear analog to an eigensolver. Once a small nonlinearity is introduced to a problem, all of these linear techniques are unavailable. All that is left for easy implementation is time marching numerical solutions. Such solutions are extremely time-consuming and fraught with risk of error and numerically induced instabilities. A common solution to this in the literature is the application of what’s called Harmonic Balance to solve the problem. While numerous articles document the application, readily available open-source tools are not available. This results in researchers choosing from two bad options: spend time writing their own harmonic balance solver or numerically simulate hoping for enough computational resources and time to obtain meaningful solutions. Mousai is intended to fill this gap. As an open source project that is easily installable and executable, a student can, with one line of code solve for the response of a Duffing Oscillator (although 3 lines are easier to understand). Mousai is written as a Python package that leverages the speed of the fftw package, if installed, or slower but still capable fft package otherwise, along with the nonlinear algebra solvers (typically Newton Krylov) distributed with SciPy. It is modular, general, highly customizable, and self-documenting (https://josephcslater.github.io/mousai/index.html) and as an open project can be enhanced and shared by the community. This presentation will introduce the math behind the solution methods, the broader algorithm, and demonstrate simply usages of Mousai along with current status and future plans.

Abstract ID: DESS2017-027

LBO, Ignition, and Spray Feature Importances from Year 3 of the National Jet Fuels Combustion Program

Erin Peiffer
University of Dayton
Joshua Heyne
University of Dayton

Climate change mitigation through the reduction of carbon emissions is becoming more crucial for the future of the planet. To reduce the carbon intense and costly alternative jet fuels approval process, the National Jet Fuels Combustion Program (NJFCP) was founded bringing federal, academic, and industry leaders together to find solutions to streamlining the process. Random forest regressions, a statistical machine learning tool, was used to analyze lean blowout (LBO), ignition, and spray tests across all areas of the program to determine top feature importances, such as chemical/physical fuel properties and test conditions, which could play a crucial part in initial fuel screening before testing. New results confirming the relationship between LBO rig sensitivity to derived cetane number (DCN) will be examined as eight swirl stabilized NJFCP rigs in now also confirm this relationship. Additionally, new ignition and spray statistical findings are presented.

Abstract ID: DESS2017-028

Multi-UAV Control and Supervision with ROS

Anthony Lamping
University of Cincinnati
Nicklas Stockton
University of Cincinnati
Bryan Brown
University of Cincinnati
Dr. Kelly Cohen
University of Cincinnati
Dr. Manish Kumar
University of Cincinnati

Advancements in UAV flight controllers have enabled researchers to develop complex UAV systems that cater to various commercial applications. This research highlights the development of a software system of one such application where the supervision and high-level control of multiple UAVs are required by a single operator. The software suite consists of two distinct but cooperative parts: the Ground Control Station (GCS) and the On-Board Computer (OBC) software packages. The software suite is built on the Robot Operating System (ROS) framework and relies on a JavaScript web-based front-end for display to the operator. ROS provides a common message passing interface for a software system and a collection of robot-specific tools, including navigation and visualization. Utilizing well-known ROS packages, such as ROSlibJS and Micro Aerial Vehicle Robotic Operating System (MAVROS), the software system is platform agnostic, capable of communicating with any flight controller that implements the Micro Air Vehicle Link (MAVLink) communication protocol.

Abstract ID: DESS2017-030

Economically Improving Signal Strength in Fiber Optic (EFPI) Strain Sensors

James Sebastian
University of Dayton Research Institute
William Boles
Air Force Research Laboratory
Bryan Eubanks
Air Force Research Laboratory
James Taylor
Air Force Research Laboratory

Characterizing advanced aerospace structures requires testing under ever-harsher environments, including elevated temperatures and superimposed acoustic loading. Using traditional strain gages under these conditions can be difficult. Fiber optic gages using extrinsic Fabry-Perot interferometers (EFPI) are promising for many situations. The signal strength from these gages can be substantially improved by using a metallic, rather than glass fiber reflector in the sensors, but this creates issues with thermal response. High quality reflectors consisting of a metallic coating on the end of a glass fiber were inexpensively constructed using coatings intended for consumer and hobbyist ceramic tablewear, and preliminary testing shows improvements in signal strength comparable to that from solid metal reflectors.

Abstract ID: DESS2017-039

Digital Holographic Microscopy based on Reflective Point Diffraction

Hongjie Zhao
Wright State University
Zifeng Yang
Wright State University

With the advantages of whole-filed, quantitative and non-contract measurement and no special treatment to specimen, digital holographic microscopy has been applied to rapid 3D microscopic imaging as an extremely important tool for tests and analysis. However, studies on improving system stability and real-time ability are still important topics in the digital holographic microscopy field. As a simple common-path configuration, the point diffraction digital holographic microscopy has been an important technique in 3D microscopic imaging. However, there are still some drawbacks for traditional point diffraction digital holographic microscopy, such as the complex pinhole assemblies and difficult operations to introduce phase shifts. The digital holographic microscopy based on reflective point diffraction (RPD-DHM) is proposed with simple configurations, less restrictive limitations, and the high-speed. Stable quantitative measurements can be achieved by introducing high speed temporal phase-shifting, simultaneous phase-shifting and carrier phase-shifting technologies, which based on the analysis of the polarizing modulation characteristic of polarizing beamsplitter (PBS) and the phase-shifting characteristic of grating. This study can provide new horizons for the digital holographic microscopic imaging with high resolution, high efficiency and long-term stability, and can be applied widely in 3D microscopic imaging, such as micro-nano manufacturing and biomedicine.

Abstract ID: DESS2017-042

High-speed 2D Raman imaging

Naibo Jiang
Spectral Energies LLC
Paul Hsu, Jason Mance, Sukesh Roy
Spectral Energies LLC
Yue Wu, Mark Gragston, Zhili Zhang
Spectral Energies LLC
Joseph Miller, James R. Gord
Air Force Research Laboratory

High-speed 2D Raman imaging Naibo Jiang, Paul Hsu, Jason Mance, Sukesh Roy Spectral Energies, LLC Yue Wu, Mark Gragston, Zhili Zhang University of Tennessee, Knoxville Joseph Miller, James R. Gord Air Force Research Laboratory Abstract is currently waitting for public release process.

Abstract ID: DESS2017-043

Fiber-coupled, UV–SWIR hyperspectral imaging sensor for combustion diagnostics

Paul Hsu
Spectral Energies LLC
Naibo Jiang, Daniel Lauriola, Sukesh Roy
Spectral Energies LLC
Joseph Miller, James Gord
Air Force Research Laboratory

Wait for public release

Renewable and Clean Energy

Abstract ID: DESS2017-063

A Look at the Optimum Slope of a Fixed Solar Panel for Maximum Energy Collection for a One Year Time Period

Salah Alhaidari
Wright State University
Dr.James Menart
Wright State University

Solar energy is becoming one of the most important renewable energy technologies in use today. For this reason we must orientate solar panels so that they collect as much solar energy as possible. The amount of solar energy that is collected by a solar panel depends on the tilt angle of the panel with respect to the horizontal plane of the earth. This work looks at the standard recommendation that says this tilt angle should equal the latitude of the location of the panel. Our work finds that there are small deviations from the standard recommendation and that these deviations increase at higher latitudes. While these deviations are small, they provide more beam energy collection at no change in initial cost. Last year, we presented this analysis and calculation ignoring the effects of the atmosphere. This year results will be presented including the effects of the atmosphere. In particular, a clear atmosphere is considered. This presentation will provide the analysis used to get these results, as well as a number of results. A comparison between the optimum tilt calculated ignoring the atmosphere and that calculated including the atmosphere will also be presented.

Abstract ID: DESS2017-082

Computer Program for Optimum Design and Analysis of Wind Turbine Rotors

Valentina Jami
Wright State University
Dr. James Menart
Wright State University

Recently, more and more emphasis has been given to generating electrical energy with renewable sources due to the many advantages it processes over conventional energy sources. Among the many ways currently available to generate electrical energy, wind is currently the cheapest. As part of this project a computer program has been developed based on blade element momentum theory that can be used to design an optimum wind turbine rotor. This computer program performs three tasks, it designs a wind turbine rotor for a specified wind speed, it analyzes the wind turbine rotor performance for other wind speeds, and it determines the performance of this rotor for wind conditions at a specific site. In this presentation a wind turbine rotor using three NREL S-series airfoils, an S818 airfoil for the root, a S817 for the primary section, and a S816 airfoil for the tip, is designed and analyzed. This newly designed rotor is then used to see what energy it can extract from the wind if placed in Eaton Ohio.

Abstract ID: DESS2017-088

Computational Modelling of a Williams Cross Flow Turbine

Sajjan Pokhrel
Wright State University
James Menart
Wright State University
Subramania I. Sritharan
Central State University

Hydropower is the most used renewable energy source in the world. While it is well known that large hydropower facilities, like the Hoover Dam, provide large amounts of electrical power, there is also a tremendous opportunity for hydroelectric power generation from small scale facilities that has largely been overlooked. The work being presented here studies a new cross flow turbine called the Williams Cross Flow Turbine (WCFT), designed to extract electric energy from numerous low head, run-of-the-river, small hydropower sites. This work has focused on developing a detailed computational fluid dynamics model of the WCFT in ANSYS Fluent. This is a detailed model that is three dimensional, transient, multiphase, and includes turbulence. Last year at this conference initial results from this model were presented. This year final results are presented. These final results include a detailed comparison between a nine and twelve bladed WCFT.

Structures / Solid Mechanics

Abstract ID: DESS2017-001

Induction Coil Design for Full View and Accurate Optical Measurement of Temperature and Strain

Michelle Wong
Wayne High School
Kayla Johnson
Stivers School for the Arts
Casey Holycross
Air Force Research Laboratory
Onome Scott-emuakpor
Air Force Research Laboratory
Tommy George
Air Force Research Laboratory

Four distinct induction heating coils were designed and tested to see which one both allowed for full field view and could most effectively heat dogbone specimen. Using a FLIR camera and thermal couple, temperature of the specimen was recorded. Since the FLIR camera is used to calculate temperature it is necessary for full view in order to test how well the coil distributes heat throughout the specimen. In order to see how well the coils are working the FLIR and the thermal both give temperature of the specimen. The copper coil that was the best option consisted of three cylindrical rounds into a one inch gap back into three more cylindrical round. The Variation of temperature through the specimen test section was less than other coils with a wider field of view as well.

Abstract ID: DESS2017-016

Nonlinear Static Analysis of a Celestial Icosahedron Vacuum Lighter Than Air Vehicle

Kyle Moore
Air Force Institute of Technology
Anthony N. Palazotto PhD PE
Air Force Institute of Technology

The idea of a lighter than air vehicle (LTAV) that uses an internal vacuum to achieve buoyancy has been around since the 17th century, but advancements in engineering and manufacturing processes are just now allowing for this concept to be feasible. Research on vacuum LTAVs has been conducted at AFIT since 2013. A new design for such a vehicle, called the Celestial Icosahedron design, was proposed by Brian Cranston in 2016 but has not yet been analyzed. The design itself is composed of 9 intersecting circular hoops covered by a membrane-like skin. The planned analysis for this design will follow that of previous AFIT designs. Analysis will include a boundary condition study in order to ensure symmetry, a comparison of different sized designs (variation of diameter), and the comparison of different structural materials, as well as the structure’s nonlinear static response to a loading condition that is representative of sea-level pressure.

Abstract ID: DESS2017-018

Laser Shock Peening for Aircraft Life Extension

Colin Engebretsen
Air Force Institute of Technology
Dr. Anthony Palazotto
Air Force Institute of Technology
Dr. Kristina Langer
Air Force Research Laboratory
Capt. David Eisensmith
Air Force Research Laboratory

Laser Shock Peening (LSP) is a mechanical process that imparts compressive residual stresses into a work piece via pressure impulses initiated by laser bursts. LSP has shown great potential for increasing fatigue life and survivability of aircraft parts subjected to fracture. This process has been used on bulkheads of the F-22, and will be used on the Joint Strike Fighter as well. Initial studies in aluminum have shown that the growth of partial through-thickness cracks stops, and fatigue life is greatly extended.

Abstract ID: DESS2017-029

A finite-strain electro-magneto-elastic framework for modeling soft multiferroic materials

Hafez Tari
University of Dayton
Robert L. Lowe
University of Dayton

Magneto-electric polymer composites (MEPCs) are an emerging class of soft smart materials. A distinguishing feature of MEPCs is the ability to electrically control their magnetization, or, conversely, magnetically control their polarization. Their inherent geometric nonlinearities and strong electro-magneto-elastic coupling make them compelling candidates for disruptive technologies ranging from voltage-tunable acoustic filters and novel energy-harvesting devices to ultra-high-sensitivity magnetic field detectors. In this talk, a fully nonlinear finite-strain constitutive framework is developed to facilitate the experimental characterization of MEPCs in the laboratory. A comprehensive catalogue of free energies and constitutive equations is presented, each with a different set of independent variables corresponding to a particular physical experiment. The ramifications of invariance, angular momentum, incompressibility, and material symmetry are explored, and a neo-Hookean-type free energy with full electro-magneto-elastic coupling is considered. A representative benchmark problem is solved to illustrate the unprecedented multi-functionality of soft MEPCs, which could act as flexible load-bearing magneto-electric energy transducers with field-tunable stiffening or softening.

Abstract ID: DESS2017-046

In Depth Structural Analysis of the Hexakis Lighter Than Air Vehicle

Anthony Castello
Air Force Institute of Technology
Dr. Anthony Palazotto
Air Force Institute of Technology

The research this paper focuses on is comparing the structural differences between the 1 and 4 foot (0.3048/1.2192 meter) diameter hexakis icosahedron frame and skin for use as a vacuum lighter than air vehicle (VLTAV). The 1 ft diameter hexakis without the graphene skin demonstrated a max deformation of 0.0386722 ft (11.7873E-03 m), while the 1 ft diameter hexakis with the skin had a deformation of 0.07706693 ft (2.349E-02 m). The 4 ft diameter hexakis with the skin had smaller deformations on the order of 0.0255778 ft (7.79611E-03 m). As the VLTAV experiences larger deformations the weight to buoyancy (w/b) ratio increases as it is a function of the internal volume. The resulting analysis showed smaller stresses and deformations in the 1 ft diameter hexakis, but an unfeasible w/b ratio. The 4 ft diameter hexakis had higher stresses and deformation, but stayed well within the material limitations with a w/b ratio that could maintain buoyancy.

Abstract ID: DESS2017-056

Potential of Lighter than Air Vehicles under a Vacuum

Ruben Adorno
Air Force Institute of Technology
Anthony N. Palazotto, PhD, PE
Air Force Institute of Technology

Building a lighter than air vehicle (LTAV) with an internal vacuum remains a challenge to this day. Material strength-to-weight ratio continues to be the limiting factor for its feasibility. However, today’s advancements in materials, modeling, and manufacturing have made building this type of vehicle a theoretical possibility. While searching for feasible geometric and material combinations, AFIT students and faculty have provided multiple contributions to the scientific and engineering community, including the static and dynamic characterization of unique geometries such as the icosahedron. The intent of this presentation is to summarize the contributions made to this point, and propose a path forward and the significance of making this type of LTAV feasible.

Abstract ID: DESS2017-065

Investigation of Multi-material Projectile Impact

Aadit Patel
Air Force Institute of Technology
Dr. Anthony Palazotto
Air Force Institute of Technology

This research investigates the impact of an ogive-nose projectile against hard/brittle targets at high velocities. Specifically, it studies the penetration event of a multi-material steel and aluminum projectile against a high-strength concrete. Hypermesh software was used to model and mesh the projectile and target; and RADIOSS was used to perform the explicit dynamic analysis of the impact. The results were used to determine the loads experienced by the different materials in the warhead. This research reveals the potential for using multiple materials in designing and optimizing an additively-manufactured projectile for penetration of specific targets.

Undergraduate Project

Abstract ID: DESS2017-012

Computational Aeroelasticity Study of Prototype Aircraft

Tyler Adgalanis
Air Force Research Laboratory
Dr. Charles Tyler
Air Force Research Laboratory

A Computational Fluid Dynamics (CFD) study was performed on a prototype aerodynamic aircraft model. Previously performed wind tunnel testing results recorded a possible stall at higher angles of attack. Prior static CFD simulation and analysis was performed to compare with experimental results, but the solutions did not capture the observed stall. The current study performs simulations of static CFD for comparison with previous efforts, but also performs simulations implementing fluid-structure interaction modeling aero-elasticity. It is believed that the wing flexed and twisted during the wind tunnel test resulting in an observed dynamic stall. The goal of the aero-elastic CFD simulations was to identify the fluid-structure interaction that might have happened during testing and achieve a better correlation between the CFD data with the experimental data. CFD simulations were produced over an angle of attack of zero to twenty five degrees. The aero-elastic case did show flexure and diverted from the static CFD results, but no dynamic stall was observed in the aero-elastic CFD case and the flexure was unintuitive. Case # 88ABW-2017-4798

Abstract ID: DESS2017-013

Variable Pitch Quadcopter Flight Control

Austin Wessels
University of Cincinnati

As small unmanned aerial systems (SUAS) have become more popular in the past few years, the desire for more maneuverable SUAS has grown. Traditional quadcopters use four separate motors to control the three rotational axes, roll, pitch, and yaw, and the one translational axis, altitude. The flight controller changes the rpm of each motor to achieve stable flight. The variable pitch multirotor has a single motor powering all four rotors, and a servo motor for each rotor to control the pitch of the blades. There are a few variable pitch quadcopters on the market currently; I will focus on the Stingray 500. One advantage of a variable pitch system is the ability to use a different power source such as an internal combustion engine. This would allow increased efficiency and longer flight time. The variable pitch multirotor is also more maneuverable given that the rotors are able to produce negative thrust. This allows to vehicle to maneuver upright as well as inverted. These flight characteristics can be achieved with slight modifications to readily available flight controllers already on the market, such as the Naze32 or FrSky F3FC. The Stingray 500 with this customized flight controller will be a stable yet maneuverable SUAS.

Abstract ID: DESS2017-023

Implementation of Open Source Autopilot for Fixed Wing Aircraft on Custom Ground Station

Nicholas Degroote
University of Cincinnati
Anthony Lamping
University of Cincinnati
Dr. Kelly Cohen
University of Cincinnati
Dr. Manish Kumar
University of Cincinnati

In recent history, the UAS industry has been primarily focused on the development of multicopter drones. While many advancements have been made in this area over the past few years, there has been significantly less research in the way of open source fixed wing UAVs. In the open source world, there is currently limited setup documentation, and most prior experiments have been conducted with a preexisting ground control station. In the interest of expanding the scope of current fixed wing UAV capabilities, there is a need for more extensive research on interfacing a Pixhawk autopilot with a custom ground control station. This research will show the process involved for both using an open source autopilot to control a fixed wing aircraft, and interfacing this system with an experimental ground station. Development of this new control method will involve testing flight plans in simulation, and incrementally adding functionality into real world attempts. This system will interface with ROS (Robotic Operating System) to allow for easier inclusion of more open source software. This will be accomplished while working toward the goal of fully autonomous waypoint missions, including takeoff and landing.

Abstract ID: DESS2017-025

Controller Development for a Non-Stationary UAV Landing Platform

Nicholas Little
University of Cincinnati
Nicklas Stockton
University of Cincinnati
Dr. Manish Kumar
University of Cincinnati
Dr. Kelly Cohen
University of Cincinnati

The ability for a UAV to land on a moving platform is a capability that can greatly increase the usage of UAV’s. It not only gives the ability to have more complex missions, but creates the possibility of a completely mobile ground station as well. This is a task that cannot be accomplished without a moving platform capable of talking with the UAV. The challenge was to develop a series of python scripts that allow a Pioneer 3-AT rover to complete a mission while communicating with a UAV. By using an on-board computer and several navigation devices, the rover carries everything it needs to complete the mission and talk with the UAV. The use of ROS(Robotic Operating System) as the backbone for the rover’s software has proven invaluable and has allowed for the rover to complete the task at hand by creating the environment for the development of a controller for the rover. ROS is also a common operating system for both the UAV and rover creating an easy means of talking to each other. Further features of ROS, mainly the ROS State Machine package, or SMACH, are still being further investigated. SMACH is used to create hierarchical robot behaviors that follow a decision path based on inputs and their corresponding outputs. The research will prove whether the rover can complete more advanced, intelligent missions while using SMACH.

Undergraduate Student Presentation Competition

Abstract ID: DESS2017-006

The Effect of Inlet Pulsations on Primary Atomization of Liquid Jets

Kyle Windland
University of Cincinnati
Himakar Ganti
University of Cincinnati
Prashant Khare
University of Cincinnati

This research effort analyzes primary atomization of liquid jets subject to inlet pulsations. The liquid jet is numerically simulated on an in-house computing cluster using an incompressible volume-of-fluid (VOF) interface capturing methodology for a wide range of pressures (0.10-3.05 MPa), pulsing frequencies (1-160 Hz), nozzle diameter (100μm-500μm) and inlet velocities (10-100 m/s) for an ethanol-nitrogen system. An adaptive mesh refinement (AMR) algorithm is incorporated to enhance the computational efficiency; several criteria, including thickness, value, gradient and curvature based refinement are implemented. The numerical framework is benchmarked against published data for an ethanol jet injected in a quiescent nitrogen environment at 300K. The chamber pressure was 3.05MPa and the jet velocity was 50 m/s, which corresponds to a Weber Number (We) of 288. A mesh refinement level of 9 is used that corresponds to a minimum cell size of 2 μm and 5.4 million grid cells at the most used. Results show excellent agreement with published data for the previously mentioned conditions. It is observed that Kelvin-Helmholtz (K-H) instabilities develop on the liquid column because of the relative velocity between the liquid jet and the surrounding air. As the ethanol jet penetrates further into the chamber, the K-H waves amplify leading to the breakup of the column in the form of ligaments and droplets. The tip of the liquid column forms a mushroom-shaped “cap” or “dome” at the front. The K-H instabilities grow with time, an expected behavior based on previous studies. Further, the effect of pulsing frequency is investigated on the Sauder mean diameter (SMD) and penetration of the liquid jet.

Abstract ID: DESS2017-010

High-Fidelity Modeling and Simulations of Newtonian and Non-Newtonian Liquid Jets in Crossflow

Austin Johnston
University of Cincinnati
Prashant Khare
University of Cincinnati

Direct numerical simulations are performed for both Newtonian and shear-thinning non-Newtonian liquids in gaseous crossflow at conditions representative of an air-breathing propulsion system. The simulations are based on 3D, incompressible, Navier-Stokes equations, augmented with a volume-of-fluid (VOF) method for interface capturing. An adaptive mesh refinement (AMR) technique is adopted for solution accuracy and computational efficiency. The computational framework is validated against experimental measurements of a water jet in air crossflow. The operating conditions are p = 20 bar, uair = 28.8 m/s, uwater = 17.9 m/s, with an inlet nozzle diameter of 0.5 mm which corresponds to a density ratio of 15.5 and Weber number of 54.9. Breakup is precipitated by flattening of the liquid column and the development of instability waves on the windward side of the liquid column. The wavelength of the most prominent mode is found to be 277μm, which agrees well with experimentally obtained correlations in the literature at the same operating conditions. These waves lead to the creation of ligaments and droplets and ultimately, the fragmentation of the liquid jet. The column breakup point is found to be slightly under predicted as compared to measurements. Based on our previous experience with atomization of non-Newtonian liquid droplets and impinging jets, an increase in the amplitude of the instability wave is expected as compared to the Newtonian case. However, the detachment of ligaments and droplets will be hindered because of the shear-thinning nature of the non-Newtonian liquid.

Abstract ID: DESS2017-035

3D Printed Metal Parts with Embedded Sensors and Electronics via Ultrasonic Additive Manufacturing

Emilie Baker
The Ohio State University
Professor Marcelo Dapino and Dr. Leon Headings
The Ohio State University

Ultrasonic additive manufacturing (UAM) is a technology that utilizes ultrasonic metal welding for 3D printing of metals as part of a CNC machining center. During the UAM process, thin layers of metal foils are ultrasonically welded together forming solid and gapless parts. SolidWorks models are imported into the system through SonicCam, allowing for complex geometries to be manufactured directly from software. UAM is a solid-state welding process; as such, its operating temperatures are a fraction of the melting temperature of the metals being welded. This characteristic allows for electronics, magnets, and piezoelectric polymers such as polyvinylidene fluoride (PVDF) to be embedded into UAM parts. Furthermore, the parts with embedded PVDF are then being analyzed for coupling and signal quality.

Abstract ID: DESS2017-070

Scaling-Up the Production of Biodiesel from a Lab Bench Environment to a Continuous-Flow Reactor

Lily Behnke
Oakwood High School

This presentation describes the challenges encountered when transferring the classic biodiesel production reaction, transesterification of vegetable oil, from the lab bench setting of organic chemistry to the small-scale, continuous flow reactor setting of chemical engineering . The chronological sequence of difficulties encountered and the approach used to resolve issues is present for each individual unit operation. Research from a variety of institutions was reviewed in order to develop a systematic approach for the transformation of this lab bench reaction to a continuous-flow reactor. The compilation of background information is established and the research methods utilized to obtain and analyze experimental information are described in correlation with the issue to which each pertains. Some of these methods include calibrating pumps to establish flowrate profiles and to determine pump settings that correspond to previously derived flow rates, investigating and interpreting soap contamination data observed during pHlip tests, and designing an environment for adiabatic fluid flow. Recommendations for additional development are also discussed, including the polishing of the raw biodiesel with BD Zorb Dry Wash adsorption columns, and DW-R10 Dry Wash ion exchange resins.

Abstract ID: DESS2017-072

Reducing Passive Muscle Force: A Process for Patient-Specific Muscle Model Parameter Calibration in RTSA Patients

Kayla Pariser
University of Dayton
David R. Walker
Rehoboth Innovations LLC
Allison L. Kinney
University of Dayton

Currently there is no standardized, objective method for a surgeon to position a reverse total shoulder arthroplasty (RTSA) in a specific patient. Simulation and optimization methods have been used to analyze how surgeries affect muscle function with generic models. However, the effect of patient-specific muscle parameters on modeling realistic muscle function in the RTSA population is unknown. Calibration of patient-specific parameters via optimization is feasible, but can be time consuming. Due to the fast workplace environment, surgeons cannot afford to wait a long time for optimizations to converge. To decrease convergence time and apply these tools clinically, muscle parameter optimizations must be provided a realistic initial guess that is representative of the patient’s muscle function. To our knowledge, previous studies have not established guidelines for adjusting muscle parameter values from literature sources to patient-specific values, but one possible mechanism is reduction of passive force. The purpose of this study is to investigate how much deviation from the literature muscle parameter values is necessary in order to reduce passive force and produce more realistic muscle activations for patient-specific cases. Studies have shown that muscles primarily produce active force when the muscle is activated and do not produce excessive amounts of passive force. Therefore, we hypothesized that adjusting muscle parameters to reduce passive force would generate more realistic muscle activations and force contributions. Eight subjects with two different RTSA implants participated in this study. Patient-specific shoulder models were generated from previously collected experimental data. Muscle moment arms, joint moments, and musculoskeletal tendon lengths during isometric contractions at three positions were calculated in OpenSim, a musculoskeletal modeling software. The literature muscle parameter values for the three deltoid muscles were modified using manually chosen scaling factors chosen with the goal of reducing passive muscle force and finding common factors across all subjects for each deltoid muscle. MATLAB was used to generate plots of the muscle tendon length (lMtilda) values in order to determine if the muscle produces unrealistic amounts of passive force. In addition, plots were created of predicted vs. experimental muscle activation data and force contribution from each of the three deltoid muscles before and after the literature parameter value adjustment. Reduction of passive force produced more realistic muscle forces and activations for all eight subjects. Common scaling factors were found across all eight subjects for two of the deltoid muscles. There was an inconsistency amongst the subjects as to which deltoid required the most parameter adjustment, emphasizing the importance of patient-specific muscle parameter adjustment. Using the literature parameter values, many subjects displayed a trend in which the muscle activation was minimal, but the predicted muscle force was very high. Once the parameters were adjusted, however, the muscle activation and force contribution became more realistic for all three deltoid muscles for all eight subjects. This study illustrates the need for adjustment to the commonly used literature muscle parameter values to generate patient-specific models that more accurately reflect a RTSA patient’s muscle activations and muscle force contributions.

Abstract ID: DESS2017-103

A New Finite Difference Scheme to Study Reaction-Diffusion Models

William Shovelton
University of Dayton

In this work, the applications and capabilities of a particular class of finite difference schemes will be discussed in relation to reaction-diffusion equations. This numerical method is beneficial because of the large number of nonlinear partial differential equations (NPDE) present in dynamical systems. For example, a reaction-diffusion equation can be used to model the laminar flame flow in combustion and other chemical and biological phenomenon. The particular scheme this work is concerned with is the positively preserving scheme. This method is applicable given that a relationship exists between time and space step-sizes and that initial data will always lead to positive values in future states. Reaction-diffusion equations with known exact solutions will be utilized to compare the computational results.

Poster Presentations

Engineering Education

Abstract ID: DESS2017-087

Open-Source, Virtual, Online Materials Laboratory including Tensile, Hardness, and Impact Testing

Matthew Bond
Sinclair Community College
Larraine Kapka
Sinclair Community College
Steven Wendel
Sinclair Community College
Karl Kapp
Bloomsburg University
Brian Seely
Bloomsburg University

Supported through NSF-DUE, this TUES Type 1 project is 1) developing an open source, virtual, online materials laboratory that includes tensile testing, hardness testing and impact testing laboratory simulation; 2) conducting research to compare the costs and learning outcomes for using on-site, hands-on testing equipment versus an online simulation; 3) creating close industry ties through blended learning opportunities for students; and 4) disseminating the simulation via faculty development. The project is testing the hypothesis that online learning improves outcomes and simultaneously reduces instructional costs. It is bridging a gap between existing material testing software products that are either too simple or too complex. The project is using a comprehensive assessment of student learning, along with a quasi-experimental research design, to determine the impact of the simulator on students and their instructors compared to traditional learning without the simulator. Although the proof of concept in the project pertains to a common engineering learning activity, the research is applicable to other engineering areas and other disciplines. The project includes activities that can be easily adopted by other institutions with little cost. The open-source tool being developed will be disseminated to undergraduate and high school faculty members who teach strength of materials and similar courses, thus increasing the likelihood of adoption. Access to a virtual lab will allow groups with limited resources to attain desired learning outcomes without large capital investments for tensile strength, hardness and impact strength testing equipment. Note that the scope of this project has increased from just tensile testing to also include hardness and impact testing. Final results will be presented for all three testing methods using both high school and college students as test subjects.

Abstract ID: DESS2017-101

McCook Challenge (Middle School Team)

Shirley
Scientific Touch Middle School Mccook Challenge
Esha Reddy, Nithya Kothnur, Ryan Cheng, Nathan Green, and Sohom Dey
Scientific Touch Middle School Mccook Challenge

Team Scientific Touch was excited to be part of McCook challenge to design, build and test a tethered plane powered by a Kelvin motor. Over the period of many weeks, the team built and tested multiple combinations of wing and fuselage designs while progressively aiming to reduce the plane weight while improving performance. Our first iteration of the plane was almost a 100g and could carry very little weight. Our final effort resulted in a light 60g plane that we demonstrated a maximum lift capacity of 74g when tested on a 10 ft tether radius at the USAF Museum. During the final round of testing, the team realized additional ways to improve the wing lift capacity and operating the motor at a much higher voltage than typical rating. Overall, it was a great experience to learn about aerospace and flight concepts.

Fluid Dynamics / CFD

Abstract ID: DESS2017-007

The Effect of Inlet Pulsations on Primary Atomization of Liquid Jets

Kyle Windland
University of Cincinnati
Himakar Ganti
University of Cincinnati
Prashant Khare
University of Cincinnati

This research effort analyzes primary atomization of liquid jets subject to inlet pulsations. The liquid jet is numerically simulated on an in-house computing cluster using an incompressible volume-of-fluid (VOF) interface capturing methodology for a wide range of pressures (0.10-3.05 MPa), pulsing frequencies (1-160 Hz), nozzle diameter (100μm-500μm) and inlet velocities (10-100 m/s) for an ethanol-nitrogen system. An adaptive mesh refinement (AMR) algorithm is incorporated to enhance the computational efficiency; several criteria, including thickness, value, gradient and curvature based refinement are implemented. The numerical framework is benchmarked against published data for an ethanol jet injected in a quiescent nitrogen environment at 300K. The chamber pressure was 3.05MPa and the jet velocity was 50 m/s, which corresponds to a Weber Number (We) of 288. A mesh refinement level of 9 is used that corresponds to a minimum cell size of 2 μm and 5.4 million grid cells at the most used. Results show excellent agreement with published data for the previously mentioned conditions. It is observed that Kelvin-Helmholtz (K-H) instabilities develop on the liquid column because of the relative velocity between the liquid jet and the surrounding air. As the ethanol jet penetrates further into the chamber, the K-H waves amplify leading to the breakup of the column in the form of ligaments and droplets. The tip of the liquid column forms a mushroom-shaped “cap” or “dome” at the front. The K-H instabilities grow with time, an expected behavior based on previous studies. Further, the effect of pulsing frequency is investigated on the Sauder mean diameter (SMD) and penetration of the liquid jet.

Abstract ID: DESS2017-011

High-Fidelity Simulations of Water Jets in Air Crossflow

Austin Johnston
University of Cincinnati
Prashant Khare
University of Cincinnati

This poster presents an investigation of Newtonian liquid jets in a gaseous crossflow at conditions representative of an air-breathing propulsion system using direct numerical simulations. The numerical framework is based on 3D, incompressible, Navier-Stokes equations, augmented with a volume-of-fluid method for interface capturing. An adaptive mesh refinement technique is adopted for solution accuracy and computational efficiency. The computational framework is validated against experimental measurements of a water jet in air crossflow. The operating conditions are p = 20 atm, uair = 28.8 m/s, uwater = 17.9 m/s, with an inlet nozzle diameter of 0.5 mm which corresponds to a density ratio of 15.5 and a Weber number of 54.9. Breakup is initiated by flattening of the liquid column and the development of instability waves on the windward side of the liquid column. The wavelength of the most prominent mode is found to be 277μm, which agrees well with experimentally obtained correlations in the literature at the same operating conditions. These waves lead to the creation of ligaments and droplets and ultimately, the fragmentation of the liquid jet. A state of the art ray-tracing technique is used for visualizing the flow field, such that intricate details inside the liquid phase could be analyzed.

Heat Transfer / Thermal Sciences

Abstract ID: DESS2017-020

Biomass Cookstove Thermal Efficiency and Tending Practices

Erin Peiffer
University of Dayton
Joshua Heyne
University of Dayton
Sari Mira
University of Dayton

More than 2 billion people in the world use biomass stoves for cooking and heating their homes. Due to incomplete combustion, toxic byproducts such as soot, nitrous oxides and carbon monoxide gasses form. These toxic substances contribute to pollution and can lead to serious health issues over time if inhaled leading to approximately 4 million premature deaths each year. The formation of these toxic substances can be mitigated, in part, through the introduction of increased turbulence intensity allowing for the so-called “well-stirred combustion regime”. Here we will be exploring the health, environmental, and social effects of biomass combustion in the developing world, the benefits of “rocket” technology in increasing thermal efficiency, the potential implementation of well-stirred combustion regimes to further improve upon this technology, and how improved tending practices can increase thermal efficiency for both 3 stone cookstove and clean cookstove use.

Abstract ID: DESS2017-085

Carbon Nanotube Nanocomposite Materials for Electronics Interface Enhancement

Brian Calderon
University of Dayton Research Institute
Levi Elston
University of Dayton Research Institute
Charles Ebbing
University of Dayton Research Institute
Qiuhong Zhang
University of Dayton Research Institute

Due to the low degree of contact area and weak interfacial adhesion between CNTs and the growth substrate (Cu), large thermal contact resistance is the largest challenge preventing the use of vertically aligned CNTS (VACNTs) as a thermal interface material (TIM). Although significant research has been done (this group’s previous work) regarding the growth of CNTs on reactive substrates by using an appropriate buffer layer in, there are many unanswered questions associated with using VACNTs as a thermal interface material beyond CNT synthesis. Very little has been reported regarding interfacial thermal properties, especially regarding direct growth of VACNTs on Cu substrates. This effort extends the work done previously on carbon nanotube growth, by concentrating on ways to evaluate/measure CNT-based nanocomposite thermal resistance. In this study, with the use of a laser flash measurement system, the influence of buffer layer (thickness and material) and CNT array properties (layer height and density) on the thermal diffusivity and thermal resistance of the CNT composite has been investigated. Test results identify a correlation between the CNT array density/thickness and its thermal resistance on a Cu substrate. Key words: Carbon nanotubes (CNTs), Buffer layer, Copper substrates, Interfacial thermal resistance, Laser flash

Other

Abstract ID: DESS2017-033

Python Module for Extrapolating Three-Dimensional Data from EBSD Images

Ryan Slater
Bellbrook High School
Dr. Kevin Chaput
Air Force Research Laboratory
Dr. Sean Donnegan
Air Force Research Laboratory

Awaiting Public Release

Structures / Solid Mechanics

Abstract ID: DESS2017-089

Finite-Element Modeling of Deformation, Damage, and Failure in Additively Manufactured Parts

Alex Elsbrock
University of Dayton
Rocky Bowman
University of Dayton
Dr. Robert Lowe
University of Dayton
Dr. Thomas Whitney
University of Dayton

Recently there has been increased interest in additively manufactured (AM) parts and their associated applications in the automotive, aerospace, and defense industries. This interest stems, in part, from the unique ability of AM parts to rapidly and inexpensively create complex geometries unattainable with conventional “subtractive” techniques. An important open problem in the AM community is developing computational tools capable of accurately and reliably predicting the performance (i.e., deformation and failure) of additively manufactured parts. Integral to this effort are constitutive and failure models that properly account for the inherent inhomogeneity and anisotropy of AM materials. Toward this end, we illustrate the calibration of a transversely isotropic linear elastic constitutive model for a brittle thermoplastic using data from a comprehensive mechanical testing program. This constitutive model is implemented into the nonlinear finite-element code LS-DYNA and validated using instrumented impact experiment data. A comparison of elastic force-displacement curves shows a good correlation between simulation results and experimental data.

Undergraduate Project

Abstract ID: DESS2017-071

The STEM Gender Gap: An Evaluation of the Efficacy of Women in Engineering Camps

Malle Schilling
University of Dayton

In 2017, it is not uncommon to see a classrooms full of engineering students with very few women in the room. While there might be more women entering into the field of engineering today compared to the mid-20th century, their relative absence in the field has not gone unnoticed. To combat this gender gap, colleges and universities have employed outreach programs and developed summer engagement opportunities that allow women to explore engineering before they graduate from high school. As these programs continue to grow, it should be explored how they are affecting the women who participate in them. To navigate this issue, a single-sex female engineering camp and a co-ed engineering camp were observed and consenting participants from both camps were given pre-camp and post-camp surveys. These surveys were meant to explore the effects the week-long camps had on the participants, and observation notes were taken during instructional sessions and activities to provide context for the survey responses. The results of the survey showed that the consenting female-identified participants from the single-sex camp were positively affected by their camp experience: the change from pre-camp to post-camp responses showed a positive shift in how they viewed engineering and their self-efficacies regarding becoming an engineer. In contrast, the post-camp results showed that the female-identified participants from the co-ed camp did not experience as great a positive shift in how they viewed engineering, and their self-efficacies towards becoming an engineer decreased. A comparison of the responses from female-identified participants and male-identified participants also supports existing research and theory that explains women showing a weaker identification with math than men. These results suggest two things: a co-ed camp model is not the ideal model for fostering women’s interest in engineering, and a single-sex camp model has positive effects on the women who attend and participate.