Mechanical Engineering Commons^™

Mechanical Characterization Of Accelerated Human Lumbar Disc Degeneration, John Sessions, Dr. Anton Bowden

Journal of Undergraduate Research

It is reported by the American Academy of Orthopeadic Surgeons that in 2005, 24% of the population sought treatment for back pain [1]. Additionally, Americans spent over $85.9 billion (2005) on health treatment costs related to back problems with the vast majority being connected to disc degeneration [1]. Despite the vast sum of money being spent on treatment of disc degeneration, the leading surgical treatments for disc degeneration (spinal fusion, total disc replacement) have been shown to increase degeneration at the discs in adjacent levels to the surgery [2].

High-Speed, Three-Dimensional Quantification Of Ladybug (Hippodamia Convergens) Flapping Wing Kinematics During Takeoff, Ryan B. George, Dr. Scott L. Thomson

Journal of Undergraduate Research

Ladybug wing and body kinematics during takeoff is explored using high-speed stereoscopic imaging. Recordings of the specimens during flight are acquired at a rate of 3000 frames per second. A direct linear transformation algorithm is performed using custom implementation in Matlab to quantify positions of selected locations on the body, forewings (elytra), and hindwings. Design and setup of instrumentation and analysis procedures are explained. Flapping frequency is reported. Significant motion of the elytra and other findings are presented and their applications are discussed.

Transtibial Suspension, Peter Jepsen, Dr. Anton Bowden

Journal of Undergraduate Research

Amputees in developing countries struggle to find employment because of their disabilities, but also struggle to afford the artificial limbs that are available to them. Further compounding the problem is the lack of comfortable fitting prosthetics, which are hard to find and design even in advanced nations. I researched, designed and tested suspension systems that could be made for a transtibial (below the knee) prosthetic leg that would be both comfortable and inexpensive.

Optimizing Cvt Performance For A Sae Mini-Baja Application, Jisang Sun, Dr. Robert H. Todd

Journal of Undergraduate Research

The Continuously Variable Transmission (CVT) is a mechanical device that transfers power from an engine to another device such as a gear box or reducer. It mainly consists of three major parts; a speed sensitive drive pulley, a torque sensitive driven pulley and a V-belt. A CVT has the ability to adjust the gear ratio between the engine and the gear box automatically based on engine RPM and the torque needed to drive the driven pulley. CVT’s are widely used in special purpose vehicles such as all terrain vehicles (ATV’s) and snowmobiles. CVT’s are also used for the national Mini-Baja …

Mathematical Model Of Friction Stir Welding, Jeremy D. Webb, Dr. Russell Daines

Journal of Undergraduate Research

Friction Stir Welding (FSW) is a semi-solid state joining process. The process utilizes a threaded pin tool “stirring” two aluminum plates together as it “sews” the seam together. One application of this process would replace the use of rivets to join aluminum paneling on commercial aircraft.

Analysis Of A Compliant Centrifugal Clutch Using Computeraided Engineering Tools, James D. Baker, Dr. Larry L. Howell

Journal of Undergraduate Research

Contemporary engineering has received the benefits of computer-aided engineering (CAE) tools that automate and simplify the design of mechanical systems. However, such tools do not provide direct support for the specific field of compliant mechanisms, whose behavior can require difficult techniques for design and synthesis. Compliant mechanisms utilize flexible segments instead of joints, to achieve their motion. It was proposed that two CAE tools, namely Pro/ENGINEER and ADAMS/View, along with a method for analyzing compliant mechanisms known as the pseudo-rigid-body model, could greatly reduce the time and effort required to generate accurate results in the analysis of a compliant centrifugal …

The Design And Synthesis Of A Compliant Bicycle Derailer, Matthew Christensen, Dr. Larry L. Howell

Journal of Undergraduate Research

Compliant mechanisms are those which gain part or all of their motion from the flexibility of their parts. For example, the motion of a hinge can be alternatively provided by a pin (like a hinge on a door), or by a thin flexible member (like a hinge in the cover of a book). The door hinge is easily designed by selecting brackets and a pin with adequate strength to support the loads. The book hinge is more difficult to design. The book has additional considerations like designing the material thin enough to bend, thick enough to bear the load, and …

Small Uavs For Perch And Stare Missions: Ground Locomotion And Self-Launch, Stephen Carlson, Dr. Jerry Bowman

Journal of Undergraduate Research

The mission of this project was the development of an Unmanned Air Vehicle capable of complete autonomy in a terrestrial environment. Using a jumping system for zero-distance take-offs and the addition of ground locomotion devices and energy harvesting systems, the vehicle could operate indefinitely without human assistance. Although this aircraft is unfinished, it and later design attempts have been tested to satisfy the basic fundamentals of this mission. The project will be continued until the stated mission objectives are achieved.

The Development And Refinement Of Constant-Force Mechanisms For Use In Future Applications, Brent L. Weight, Dr. Larry L. Howell

Journal of Undergraduate Research

A compliant mechanism is one in which the mechanism’s motion comes from deflection of one or more of its members. Compliant mechanisms offer several advantages over rigid-body mechanisms. The member deflection characteristic of compliant mechanisms results in the ability to store energy directly within the member, eliminating the need for additional energy storage devices (i.e. springs) found in rigid-body mechanisms. The member deflection also allows for the replacement of pin joints with small length flexural pivots, or living hinges, thereby reducing part count and assembly time. In fact, one of the most significant advantages of compliant mechanisms is their ability …

Freeze-Thaw Effect On Mechanical Properties Of Bovine Ligaments, Alan Bordon, Dr. Anton Bowden

Journal of Undergraduate Research

My ORCA grant proposal was to study the effect that freezing and thawing a soft tissue has on the results of the mechanical property tests (i.e how strong) performed on the tissue. I was to study the effect of a single and multiple freeze/thaw cycles on the tissue. My hypothesis was that there was a deleterious effect and this was important to account for when doing testing with soft tissue.

Flow-Induced Crystallization Of Isotactic Polypropylene And Random Polyethylene–Polypropylene Copolymers, Frederic Aubin

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Flow-induced crystallization (FIC) has been investigated for decades but the effect of molecular characteristics that hinder crystallization—such as the presence of random comonomers— on FIC remains scarcely explored. Flow greatly enhances crystallization kinetics and can induce the formation of highly oriented morphologies that affect final properties (i.e. stiffness, permeability, thermal conductivity, elastic modulus, etc.). Therefore, understanding FIC remains particularly important for developing predictive models to allow optimization of processing techniques involving flows.

Polypropylene represents ~ 40% of the global polyolefin production. The addition of ethylene comonomer allows their use as engineering plastics because of their particular toughness and flexibility. This …

The Determination Of Grain Boundary Structure, Ryan J. Larsen, Dr. Brent L. Adams

Journal of Undergraduate Research

A growing focus of material science research is relating material properties to grain boundary geometry. The purpose of my research has been to improve current methods of determining grain boundary geometry and to relate interface geometry to sensitization of AISI type 304 stainless steel. Sensitization is the formation of chromium carbides that occurs in a temperature range of 500-800 °C, and makes the material more susceptible to intergranular stress corrosion cracking and stress corrosion cracking.

The Effect Of The Duct Area To Rocket Area Ratio And Rocket Expansion On Ejector-Rocket Performance, Michael I. Kellogg, Dr. Russell Daines

Journal of Undergraduate Research

Space is the final frontier. That has been generally believed since Sputnik went up in the 1950’s, but in spite of this optimistic belief, homesteaders have not yet begun to settle Mars, nor have businesses sponsored ventures to other planets. One of the reasons that the final frontier is so quiet is the prohibitive expense of getting there. Currently it cost about $10,000 to launch a pound of payload into low earth orbit.1 NASA, in an effort to lower the cost of launching payloads into space, has been encouraging researchers to develop alternative launch vehicles to replace the Space Shuttle. …

Particle Morphology And Elemental Composition Of Heavy Fuel Oil Ash At Varying Atomization Pressures, Daniel Abraham Tovar

Theses and Dissertations

Land-based turbine engines are currently used to burn heavy fuel oil (HFO), which is a lower cost fuel. HFO contains inorganic material that forms deposits on turbine blades reducing output and efficiency. Magnesium based additives are used to inhibit vanadium pentoxide deposition and reduce the corrosive nature of the gas and deposits in the hot gas path of the gas turbine. The focus of this study was to determine particle morphology and elemental composition of ash when firing HFO in an atmospheric combustor at various fuel injector atomization pressures. Prior to firing, the HFO was washed with water to remove …

Examination Of Material Flow Characteristics In Friction Stir Welding, S. James Felsted, Dr. Tracey W. Nelson

Journal of Undergraduate Research

Friction Stir Welding is a solid state joining process that makes possible the joining of materials that were previously difficult or impossible to weld. A closer examination of friction stir welding shows that welding occurs because of mechanical mixing, frictional heating, and forging. Welds are made on a conventional milling machine that powers a steel tool consisting of a shank, shoulder, and pin (1). This process is being investigated in order to better understand the interaction of the tool with the material and the nature of the material deformation.

Cyclic Durability Of A Solid Oxide Fe-Air Redox Battery Operated At 650°C, Xuan Zhao, Yunhui Gong, Xue Li, Nansheng Xu, Kevin Huang

Faculty Publications

The recently developed rechargeable solid oxide metal-air redox battery has shown a great potential for applications in mid- to large-scale stationary energy storage. Cyclic durability is one of the most important requirements for stationary energy storage. In this study, we report the cyclic durability of a solid oxide Fe-air redox battery operated at 650°C. The battery was continuously cycled 100 times under a current density of 50 mA/cm² with rather flat performance, producing an average specific energy of 760 Wh/kg-Fe at a round-trip efficiency of 55.5%. The post-test examination indicated that the performance losses could arise from the fuel-electrode …

Cyclic Durability Of A Solid Oxide Fe-Air Redox Battery Operated At 650°C, Xuan Zhao, Yunhui Gong, Xue Li, Nansheng Xu, Kevin Huang

Faculty Publications

The recently developed rechargeable solid oxide metal-air redox battery has shown a great potential for applications in mid- to large-scale stationary energy storage. Cyclic durability is one of the most important requirements for stationary energy storage. In this study, we report the cyclic durability of a solid oxide Fe-air redox battery operated at 650◦C. The battery was continuously cycled 100 times under a current density of 50 mA/cm2 with rather flat performance, producing an average specific energy of 760 Wh/kg-Fe at a round-trip efficiency of 55.5%. The post-test examination indicated that the performance losses could arise from the fuel-electrode of …

The Mechanics Of Intracranial Loading During Blast And Blunt Impacts: Experimental And Numerical Studies, Veera Selvan Kuppuswamy

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Head injuries in an explosion occur as a result of a sudden pressure changes (e.g. shock-blast) in the atmosphere (primary injury), high velocity impacts of debris (secondary injury) and people being thrown against the solid objects (tertiary injury) in the field. In this thesis, experimental and numerical approaches are used to delineate the intracranial loading mechanics of both primary (blast) and tertiary injuries (blunt).

The blast induced head injuries are simulated using a fluid-filled cylinder. This simplified model represents the head-brain complex and the model is subjected to a blast with the Friedlander waveform type of loading. We measured the …

Model Reference Robust Control For Marine Propulsion Systems With Model Uncertainty Caused By Hull Deformation, Zhixiong Li, Xinping Yan, Li Qin, Chengqing Yuan, Zhongxiao Peng

Journal of Marine Science and Technology–Taiwan

A marine propulsion system can be strongly coupled with the hull deformation in a large-scale ship. The interaction of this coupling dynamics increases the nonlinearity and complexity of the control model. Traditional control method based on the empirical PID (proportion-integration-differentiation) parameters has difficulty in dealing with the model uncertainty caused by the hull deflection. However, up to date, limited work has been done to address the model uncertainty problem of the marine propulsion system. It is therefore imperative to develop feasible and effective control systems that take the model uncertainty into account. In this study, a new method based on …

Vision-Based Process Monitoring For Laser Metal Deposition Processes, Sreekar Karnati, Niroop Matta, Todd E. Sparks, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Laser Metal deposition is a process with immense scope and promise for becoming a robust manufacturing technology in the near future. Monitoring process variables is very instrumental in process planning and output monitoring. The current work deals with realizing the effect of power modulation on size of the high temperature region during deposition with varying powder feed. A thermal camera was used to visualize and analyze the deposition process. The area of the high temperature region through the deposition was identified and compared to realize the effect of each variable parameter during deposition. The power modulation was fruitful in modulating …

Effect Of Architecture And Porosity On Mechanical Properties Of Borate Glass Scaffolds Made By Selective Laser Sintering, Krishna C. R. Kolan, Ming-Chuan Leu, Greg Hilmas, Taylor Comte

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The porosity and architecture of bone scaffolds, intended for use in bone repair or replacement, are two of the most important parameters in the field of bone tissue engineering. The two parameters not only affect the mechanical properties of the scaffolds but also aid in determining the amount of bone regeneration after implantation. Scaffolds with five different architectures and four porosity levels were fabricated using borate bioactive glass (13-93B3) using the selective laser sintering (SLS) process. The pore size of the scaffolds varied from 400 to 1300 μm. The compressive strength of the scaffolds varied from 1.7 to 15.5 MPa …

Additive Manufacturing Laser Deposition Of Ti‐6al‐4v For Aerospace Repair Applications, Nanda Kumar Dey, Frank W. Liou, C. Nedic

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Parts or products from high performance metal are very expensive, partly due to the processing complexities during manufacturing. The purpose of this project is to use additive laser deposition and machining processes to repair titanium parts, thus extending the service life of these parts. The study broadly included preparing the defects, laser deposition, machining, sample preparation and mechanical tests. Comparative study of mechanical properties (UTS, YS, percentage elongation) of the repaired samples to the ideal conditions was undertaken. The research throws up interesting facts where the data from the test sample shows enhancement of properties of the repaired part.

Development Of Freeze-Form Extrusion Fabrication With Use Of Sacrificial Material, Ming-Chuan Leu, Diego A. Garcia

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The development of Freeze-form Extrusion Fabrication (FEF) process to fabricate three-dimensional (3D) ceramic parts with use of sacrificial material to build support sections during the fabrication process is presented in this paper. FEF is an environmentally friendly, additive manufacturing process that builds 3D parts in a freezing environment layer-by-layer by computer controlled extrusion and deposition of aqueous colloidal pastes based on computer-aided design (CAD) models. Methyl cellulose was identified as the support material, and alumina was used as the main material in this study. After characterizing the dynamics of extruding alumina and methyl cellulose pastes, a general tracking controller was …

Experimental Investigation Of Different Cellular Lattice Structures Manufactured By Fused Deposition Modeling, Osman Iyibilgin, Cemil Yigit, Ming-Chuan Leu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Experimental tests were conducted to evaluate the compressive properties (yield strength and compressive modulus) and build time for five different cellular lattice structures fabricated by the Fused Deposition Modeling (FDM) process. The lattice structures had repeating unit cells, and the shapes of the unit cell under study included honeycomb, square, diamond, triangle, and circle. Test specimens were manufactured by a Stratasys Fortus 400mc machine using ABS (Acrylonitrile Butadiene Styrene) as the part material. The five different lattice structures were compared with each other and also with the sparse and sparse-double dense build styles that are directly available from the Fortus …

Probabilistic Simulation Of Solidification Microstructure Evolution During Laser-Based Metal Deposition, Jingwei Zhang, Frank W. Liou, William Seufzer, Joseph William Newkirk, Zhiqiang Fan, Heng Liu, Todd E. Sparks

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A predictive model, based on a Cellular Automaton (CA) - Finite Element (FE) method, has been developed to simulate microstructure evolution during metal solidification for a laser based additive manufacturing process. The macroscopic FE calculation was designed to update the temperature field and simulate a high cooling rate. In the microscopic CA model, heterogeneous nucleation sites, preferential growth orientation and dendritic grain growth kinetics were simulated. The CA model was able to show the entrapment of neighboring cells and the relationship between undercooling and the grain growth rate. The model predicted the dendritic grain size, structure, and morphological evolution during …

Numerical Analysis Of Thermal Stress And Deformation In Multi-Layer Laser Metal Deposition Processes, Heng Liu, Todd E. Sparks, Frank W. Liou, David M. Dietrich

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Direct metal deposition (DMD) has gained increasing attention in the area of rapid manucooling rate, resulting in residual stresses and distortion. This paper presents a 3D sequentially coupled thermo-mechanical finite element model to predict residual stresses and deformations. The temperature distribution, thermal stress field and geometry deformation across domain are illustrated. The effect of deposition parameters on residual stress and deflections are also explored. A set of validation experiments for mechanical effects were conducted using laser displacement sensor. The comparisons between the simulated and experimental results show good agreement

Analysis Of Intervertebral Disc Degeneration Testing Method, David Williams, Dr. Anton Bowden

Journal of Undergraduate Research

This ORCA research project has focused on the determination of the effects of the order of the mechanical tests on the response of an intervertebral disc. We hypothesized that the order of the mechanical tests may influence the rate of diffusion of the Trypsin throughout the disc, affecting the biomechanical response. We have planned to determine the magnitude of this influence by using statistical techniques to analyze the data acquired. Virtually all of us (80 to 90 percent) will experience back pain in our lives. Low back pain is the leading cause of missed work days. The estimated economic impact …

Influence Of Airway Liquid Hydration And Properties On Human Vocal Fold Vibration, Preston Murray, Dr. Scott Thomson

Journal of Undergraduate Research

The purpose of this research project was to identify a fluid that has similar properties as the airway surface liquid (ASL) that covers vocal folds, and then apply it to a vibrating synthetic vocal fold model to measure its effects.

Parametric Optimization Of Wind Turbine Blades, Brycee Mcewen, Dr. Steven Gorrell

Journal of Undergraduate Research

With ever increasing concerns about the production of greenhouse gases from burning fossil fuels, more and more emphasis is being placed on researching and developing alternative and renewable energy resources. One renewable energy source that has the potential to compete with conventional fossil fuels, is wind energy. In order for wind energy to be competitive, it is necessary to make improvements in both aerodynamic and structural properties of wind turbines.

Piezoresistivity In Nickel Nanostrand Composite Materials As Studied By Three-Dimensional Reconstruction On Focused Ion Beam Serial-Sections, Oliver Johnson, Dr. David Fullwood

Journal of Undergraduate Research

The development of a large-strain sensor technology will open doors for improved engineering design and scientific research in many fields. Such a technology would allow for advances in biomechanical engineering, e.g., prosthetic limb and artificial organ design. Additionally this kind of sensor technology could be used for tactile robotics and even structural health monitoring, such as in wind turbines or architectural structures. Our research group has developed a unique Silicone/Nickel Nanostrand/Nickel Coated Carbon Fiber (Si/NiNs/NCCF) nanocomposite that can measure strains of up to 50% elongation. The purpose of this project was to investigate how the nano-scale structure of this material …