Mechanical Engineering Commons^™

Light Touch Based Virtual Cane For Balance Assistance During Standing, Sindhu Reddy Alluri

Masters Theses

"Can additional information about one's body kinematics provided through hands improve human balance? Light-Touch (LT) through hands helps improve balance in a wide range of populations, both healthy and impaired. The force is too small to provide any meaningful mechanical assistance -- rather, it is suggested that the additional sensory information through hands helps the body improve balance.

To investigate the potential for improving human balance through biofeedback through hands, we developed a Virtual Cane (VC) for balance assistance during standing. The VC mimics the physical cane's function of providing information about one's body in space. Balance experiments on 10 …

Characterization Of The Surface Condition In Aa6061 Resulting From Deep Rolling As A Function Of Common Industrial Parameters, Andrew Kenneth Layer

Masters Theses

"Roller burnishing is widely used in industry to improve the surface finish and fatigue life of components. As weight reduction continues to grow in the automotive and transportation industries, deep rolling can help maintain product performance by mitigating the increase in component stresses resulting from lower weight systems. Deep rolling parameters such as tool, applied angle, feed rate, spindle speeds, and relative tool direction all affect cycle time, product performance, and appearance. The effects of common industrial parameters on the resultant surface roughness and residual stress profiles were studied in this investigation. The samples were manufactured on a CNC lathe …

The Effect Of Cell Size And Surface Roughness On The Compressive Properties Of Abs Lattice Structures Fabricated By Fused Deposition Modeling, Leah Hope Mason

Masters Theses

"Postprocessing is an important step in many manufacturing methods, but it is especially important for additive manufacturing. Researchers looking to improve the surface roughness of acrylonitrile butadiene styrene (ABS) parts fabricated by fused deposition modeling (FDM) have determined that acetone smoothing not only achieves improved surface roughness but increases compressive strength as well. This could be very beneficial to lattice structures, which are known for already having an excellent strength to weight ratio. If the compressive strength of ABS lattice structures could be improved even further using acetone smoothing, it could expand the applications for plastic lattice structures and improve …

Multiphysics Prediction Model Of Microwave Curing For Thick Polymer Composites, Siva Dasari

Masters Theses

"Microwave curing technologies have many advantages over the traditional thermal curing methods for the manufacturing of fiber reinforced polymers, especially the processing speed and energy efficiency. Energy can be instantaneously transferred through applied electromagnetic fields and heat is generated based on dipolar rotational interactions. Microwave curing processes have been used for glass fiber composites but there are significant challenges associated with microwave curing of carbon fiber composites. Efficient heating may be difficult due to high dielectric loss associated with carbon fibers. Laminate quality will be highly dependent on the uniformity of the electromagnetic field in the material. In this work, …

Performance Evaluation Of Bmi Resin System For Thin-Ply Composites, Manoj Kumar Reddy Rangapuram

Masters Theses

"Composites materials are increasingly being used in aerospace applications over the past few years. The unique properties like high strength to weight ratio, thermal stability, fatigue and corrosion resistance set them apart from the conventional materials. Composite materials are well suited for the applications where weight is the primary concern in the design. Composites structures are vulnerable to mechanical as well as thermal loadings. Transverse micro-cracking and delamination are the most common type of failures in composite materials. The thickness of the ply being used play a key role dictating the properties of the resultant composite structure. As the ply …

Laser Machining Countersinks In Carbon Fiber Reinforced Polymer, Leon James Neely Hill

Masters Theses

“Laser machining countersinks with a frequency doubled Q-switched diode pumped Nd:YAG laser is demonstrated. Tests were conducted in 0.100" thick IM7 prepreg CFRP with [0,90]3S orientation. The HAZ is minimized to avoid stress concentrations in the epoxy matrix. A chamber and filtration system was designed and built to contain the byproducts produced in the machining process. The variables investigated are the number of repetitions in the offset path, the plunge rate, and the line energy. The research was performed over one baseline study, one parameter space exercise, two full factorial experiments, and one repeatability study. Assessment was done under an …

Controlled Switching In Kalman Filtering And Iterative Learning Controls, He Li

Masters Theses

“Switching is not an uncommon phenomenon in practical systems and processes, for examples, power switches opening and closing, transmissions lifting from low gear to high gear, and air planes crossing different layers in air. Switching can be a disaster to a system since frequent switching between two asymptotically stable subsystems may result in unstable dynamics. On the contrary, switching can be a benefit to a system since controlled switching is sometimes imposed by the designers to achieve desired performance. This encourages the study of system dynamics and performance when undesired switching occurs or controlled switching is imposed. In this research, …

Optimization Of Analytical Inverse Heat Transfer Recovery Solution, Nathan Schick

Masters Theses

This thesis describes the different methods used when trying to solve inverse heat transfer problems, particularly those involving recovering heat flux. There are currently several techniques to measure the temperature history in an object subjected to heat transfer using various temperature sensors, however these types of sensors are gradually being replaced by Temperature Sensitive Paints (TSP), a technique that is more accurate and provides a better spatial resolution. TSP is a polymer that is applied on a base object. Changes in temperature in the polymer result in variations of the luminescence intensity in the paint. These variations can be captured …

Variable Reluctance Virtual Torque Sensor For Automotive Applications, Vivek Iddum

Masters Theses

Torque sensing has been realized as one of the critical aspects in improving the dynamic vehicle performance in automotive systems. This thesis mainly presents the work on the development of a novel torque measurement method based on the estimation of nth-order flywheel angular acceleration from the variable reluctance flywheel speed sensor pulses. The number of firings in the engine determine the order of the harmonic to be used for torque estimation. The nth-order flywheel angular acceleration is computed using a micro-controller with built in timer counter and an associated signal conditioning circuit. The pulses obtained from the flywheel speed sensor …

Design Of A Portable Biogas Purification And Storage System, Anilkumar Kosna

Masters Theses

Biogas is produced from the decomposition of organic materials like manure, sewage sludge or crop fodders in anaerobic digesters. It consists mainly of 40 – 75 % of methane (CH₄), 15 – 60 % of carbon dioxide (CO₂) and trace amounts of other components. The principle constituents of biogas are similar to natural gas. Natural gas has 87 – 97 % of methane (CH₄) and 0.1 – 1 % of carbon dioxide. Natural gas is known to be an alternative fuel with a wide range of applications. The commercial purification technologies exist for large-scale …

Liquid-To-Liquid Low Grade Waste Heat Recovery Using A Two-Channel Loop, Waleed Farwana

Masters Theses

The use of thermoelectric generators (TEGs) for producing electric energy from low grade “waste heat” has been theorized to provide a sustainable and low-cost energy source for electric power plants. The purpose of this study is to model and experimentally validate a TEG device that takes advantage of low grade waste heat (approximately 100-150 degrees Celsius) in liquid form in order to generate power that can be used for various applications in the surrounding environment. This research aims to demonstrate that optimized TEG designs bear the potential to compete with other methods of low grade waste heat energy harvesting in …

Mathematical Modeling And Empirical Validation Of A Conceptual Exoskeleton For Astronaut Glove Augmentation, Joseph Kissling

Masters Theses

Space presents numerous difficulties for astronauts conducting their work, not the least of which is the spacesuit that is worn to protect them from space. It has long been known that a spacesuit is difficult to work in, especially the rigid and pressurized gloves that put strain on the astronaut's hands, frequently leading to injuries. Astronaut gloves inhibit more than 50% of their strength in some cases [1]. NASA and other space agencies have been working to alleviate these problems by attempting to mechanically augment the gloves to reduce the exertions of the astronaut. To date, no augmentation systems have …

Experimental Comparison Between Hollow Cathodes With Cermet, Lanthanum Hexaboride, And Barium Oxide Insert Materials, Nagual Simmons

Masters Theses

This thesis compares two different hollow cathode assemblies (HCA) using three different insert materials. NASA’s Jet Propulsion Laboratory (JPL) provided the H6 HCA and the Lanthanum Hexaboride (LaB₆) insert. A barium oxide (BaO) insert was purchased from Ebeam and used with the H6 HCA. The novel Cermet material was purchased from Plasma Controls, LLC and the HCA was based on the JPL H6 HCA. Plasma properties in the external region of all three inserts and the internal region of the LaB₆ were determine using two separate Langmuir probes. Various operating points were tested at a combination of …

Control-Oriented Automatic Transmission- Based Powertrain Modeling And Simulation With Judder, Harshal B. Kundale

Masters Theses

This work presents automatic transmission-based powertrain modeling. The powertrain consists of an engine, torque converter with lock up clutch, transmission gearbox, propeller shaft, and vehicle body. Simplified powertrain component models are developed for vehicle powertrain dynamic response analysis and future control work. The powertrain components are modeled with algebraic and first order non-linear differential equations. A MATLAB-based powertrain simulation system is developed to investigate the transient characteristics during lock up of torque converter. Simulation results are used in the determination of effects of judder on torque and angular velocity. Clutch judder is a self-excited vibration that occurs during the clutch …

Determination Of Chemical Notch, KChem On Aluminum And Steel When Subjected Under Slow Strain Rate Test In Corrosive Environment, Joshua Teo Lee Kuok

Masters Theses

When designing for any mechanical components or system, the question would arise as to how the material would react to the loads subjected on it? Would the component survive its service load? How would it react to environmental corrosion? To answer these questions, the technique used in this thesis paper is the Slow Strain Rate Test (SSRT) method. Aluminum and steel were chosen as the material to be tested in this paper. Al 7075-T651, and Al 6061-T651 was chosen due to its wide range of application, high strength to weight ratio and ease of machinability. It is highly used in …

Forward-Looking, Velocity-Driven, Powertrain Modeling And Optimal Control For Continuous Variable Transmission, Paresh Deshmukh

Masters Theses

This thesis is the second part of a two-part study focused on improving Continuous Variable Transmission (CVT) ratio management and control. The objective of the overall project was to develop a methodology for a vehicle with a CVT and a downsized gasoline engine to deliver the maximum vehicle fuel economy within drivability and performance constraints. The first part of this study, as described in [1], focuses on developing a cycle driven model for optimizing the CVT ratio. The study presented in this paper focuses on developing a velocity driven model to simulate the real-time behavior of a vehicle. The results …

Investigation Of Discrete Element Methods For Stud To Turf Interactions, Justin Rittenhouse

Masters Theses

Artificial turf is frequently used in sports today and attempts to advantageously replicate a natural grass/soil playing surface. Despite numerous advantages, the technology is correlated with an increase in injuries. The concept behind this research is to create and validate a discrete element model (DEM) for the ground/foot interaction through the use of open source software. After validation, the goal is to analyze an arrangement of studs to determine what role stud geometry plays on torque [N-mm] and force [N] generation. The validation data was provided through laboratory experiments. Three football studs attached to a rigid bracket were turned at …

Enhancement Of Performance Of Micro Direct Ethanol Fuel Cells By Structural Modification, Sindhuja Valluri

Masters Theses

“Direct Ethanol Fuel Cells (DEFC’s) are becoming more important in current energy conversion devices because of their higher efficiency compared to other fuel cells. However, the performance of current DEFC’s is not efficient in providing energy to meet increasing energy demand. The objective of this work is to make the cell compact and at the same time improve performance. For this purpose, we have removed gasket and endplates to make structure compact and increased surface area by developing a new corrugated structure. This work also uses 3D printing technology Fused Deposition Modeling (FDM) to make pocket backing case to improve …

Advanced Process To Embed Optical Fiber Sensors Into Casting Mold For Smart Manufacturing, Raghavender Reddy Jakka

Masters Theses

"Optical fiber sensors embedded in metals with distributed sensing can sense temperature at multiple points with single fiber. This is useful for smart manufacturing like structural health monitoring in aerospace industry and smart molds in manufacturing plants. There is a huge difference in thermal coefficient of expansion for fiber and metal. This is the reason for the increase in sensitivity for embedded fiber sensors. However, at high temperatures, the stress on the fiber increases, eventually damaging the sensor. The fiber-metal interface determines the sensor performance. A tight interface results in high sensitivity and a gap in the interface enhances sensing …

Multiscale Approaches Toward Advanced Lithium-Ion Battery: From Nano To Meso Scale, Susmita Sarkar

Masters Theses

“Battery performance and its degradation are determined by various aspects such as the transport of ions and electrons through heterogeneous internal structures composed of constituent particles, kinetic reactions at the interfaces, and a corresponding interplay between mechanical, chemical, and thermal responses. Further, modern battery materials require a variety of engineering processes such as coating, doping and mixing. As a result, in order to fully understand the behavior of the battery material and improve battery performance, it is necessary to understand and control the individual particle behavior and then connect it to the electrode. This study elucidated the physical phenomena associated …

Laser-Aided Additive Manufacturing Of Glass, John Michael Hostetler

Masters Theses

“This thesis presents various approaches for the laser-aided additive manufacturing of glass. First, a technique is investigated to create free-form, low to zero coefficient of thermal expansion structures out of silica-gel. A CO₂ laser was coupled through a gantry system and focused onto a binder-free silica-gel powder bed (15-40 μm particles). Prior to writing each layer, powder is dispensed by sifting it onto the build platform as opposed to a conventional wiper system, avoiding contacting and potentially damaging sensitive parts. After deposition, the parts are annealed in a furnace to increase their strength. The influence of various process parameters …

Controlling Phase Fractions Of 304l-Ss In Selective Laser Melting Using Cooling Rate, Eberechukwu Anthony Okoro

Masters Theses

"This study examines the thermal profile and the ferrite-austenite phase fractions upon heating and cooling of 304- stainless steel powder via Selective Laser Melting (SLM). Experiments were performed to validate the ABAQUS finite element model, while the phase transformation simulation was performed using MatCalc and ThermoCalc. A correlation between the thermo-mechanical changes in ABAQUS and the microstructural changes from MatCalc was obtained by matching their cooling rates. The result indicates that cooling rate has a significant effect on the phase fractions of FCC and BCC formed in 304L stainless steel via the SLM process. The results also indicate that for …

Investigation Of The Information Provided By Light Touch For Balance Improvement In Humans, Anirudh Saini

Masters Theses

"This study investigates the information provided by Light Touch (LT) in improving human postural stability without mechanical assistance. Light Touch, an interaction force with a magnitude about 1 N, is known to improve postural stability in humans during quiet standing. However, the nature of the information from LT that helped improve balance is yet unknown. In this work, we hypothesized that LT provides information about one's body kinematics. We used a haptic robot to provide modulated, measurable light interaction force on the high back haptic location of humans to provide body kinematics-dependent information through LT. Standing balance experiments were performed …

Numerical Modeling Of Capillary-Driven Flow In Open Microchannels: An Implication Of Optimized Wicking Fabric Design, Mehrad Gholizadeh Ansari

Masters Theses

"The use of microfluidics to transfer fluids without applying any exterior energy source is a promising technology in different fields of science and engineering due to their compactness, simplicity and cost-effective design. In geotechnical engineering, to increase the soil's strength, hydrophilic wicking fibers as type of microfluidics have been employed to transport and drain water out of soil spontaneously by taking advantage of natural capillary force without using any pumps or other auxiliary devices. The objective of this study is to understand the scientific mechanisms of the capability for wicking fiber to drain both gravity and capillary water out of …

Computational Investigation Of Polymer Electrolyte Membrane Fuel Cell With Nature-Inspired Fibonacci Spiral Flow Field, Suleyman Kose

Masters Theses

"Polymer electrolyte membrane fuel cells (PEMFC) are promising clean energy devices. The flow field design has crucial role in PEMFC performance for effective distribution of reactants and removal of products. Several nature-inspired flow field designs have recently been proposed in the literature. Common characteristics of these designs were sudden changes in the flow direction through sharp bends and flow field geometries restrained to areas having corners. In this thesis, Fibonacci spiral configuration, which is found in the nature from hurricanes to seashells, was considered for flow field pattern of a PEMFC. Contrary to the bio-inspired designs proposed in previous studies, …

Designed Extrudate For Ceramic Additive Manufacturing, Devin Mcmillen

Masters Theses

"The objective of this thesis work was to design ceramic paste systems that assist in achieving a high theoretical density ( > 95%) after deposition by a novel additive manufacturing process, i.e. Ceramic On-Demand Extrusion (CODE). The work is encompassed in five main sections: Sections 1 and 2 provide an introduction and literature review of relevant topics for the following sections of experimentation. Section 3 provides an analysis of a reaction chemistry to identify three discrete materials that could be combined via CODE and result in zirconium diboride (ZrB₂) post-sintering. Section 4 describes the development of a high solids …

Smart Augmented Reality Instructional System For Mechanical Assembly, Ze-Hao Lai

Masters Theses

"Quality and efficiency are pivotal indicators of a manufacturing company. Many companies are suffering from shortage of experienced workers across the production line to perform complex assembly tasks such as assembly of an aircraft engine. This could lead to a significant financial loss. In order to further reduce time and error in an assembly, a smart system consisting of multi-modal Augmented Reality (AR) instructions with the support of a deep learning network for tool detection is introduced. The multi-modal smart AR is designed to provide on-site information including various visual renderings with a fine-tuned Region-based Convolutional Neural Network, which is …

Model Predictive Power Management Of A Hybrid Electric Propulsion System For Aircraft, Tyler J. Wall

Masters Theses

This work presents the switched optimal power flow control for an aircraft with a hybrid electric propulsion system. The propulsion system is a switched system that operates in either of two modes: (i) battery discharging and electric motor propelling and (ii) battery charging and electric motor generating. The aircraft model and components that form the hybrid propulsion system are modeled as either an algebraic power source/sink or as a dynamic model with appropriate power and state interconnections. With the system model defined, a model predictive control power management strategy is set fourth which minimizes a performance index that includes altitude …

Finite Element Analysis Of Tibiofemoral Contact Mechanics, Erika Fojtik

Masters Theses

The effects of lateral meniscus posterior root avulsions (LMPRA) have been studied in combination with meniscofemoral ligament (MFL) deficiencies. The purpose of this study is to validate a set of biomechanical finite element analyses against previously reported experimental results to predict the contact area and peak contact pressure in the lateral tibiofemoral compartment of the knee during lateral meniscal root avulsions in combination with MFL deficiencies. Patient specific MRI data was used to develop finite element models for three distinct testing conditions: 1) intact, 2) lateral meniscus posterior root avulsion, and 3) lateral meniscus posterior root avulsion with deficient meniscofemoral …

Development Of Empirical And Virtual Tools For The Study Of Bicycle Safety, Brent Kostich

Masters Theses

Bicycles have been used as a form of non-motorized transportation for several hundred years. Recently, their use in the transportation realm has been reinvigorated because of growing population densities and efforts to improve environmental sustainability. However, a large deterrent for public use of the bicycle is concern over its level of safety in the transportation environment. The goal of this thesis is to develop two complementary research tools that advance the study of bicycle safety factors.

First, an instrumented probe bicycle (IPB) is constructed from the ground up. The bicycle is outfitted with an array of sensors that are integrated …