Mechanical Engineering Commons^™

A Method For The Characterization And Selection Of Compliant Joints, Ronald George Saleeby

All Theses

A compliant joint is a connection between two bodies that derives its movement from the deflection of flexible members rather than rigid connections, like traditional joints. Compliant joints have potential advantages that include longer part life, reduction of parts in assemblies, and reduced wear. Traditional compliant mechanism design methodologies have limitations involving the burden of necessary knowledge required to satisfactorily use them. The method presented in this thesis was developed to provide compliant joint design solutions independent of the traditional methods of compliant joint design by allowing the selection of compliant joints from a repository. The repository is populated by …

Surface Characterization Of 316l Stainless Steel For Biomedical Applications, Lawrence Cano

Theses and Dissertations - UTB/UTPA

Stainless steel alloys play an important role in the field of biomaterials due to their exceptional corrosion resistance and biocompatibility. These alloys have the capability to enhance the quality of a human life by altering various structures of human physiology. The close proximity these alloys have with destructive body fluids, ion dissolution is a detrimental cause from the corrosion initiative and may cause unfavorable reactions. A view on developing an improved compatible surface for the human body leads to implementation of different chemical surface modifications used for creating features that must be corrosion resistant and biologically active without changing the …

Preparation And Characterization Of Copper-Doped And Silver-Doped Titanium Dioxide Nano-Catalysts For Photo Catalytic Applications, Haya Abdel Ra’Ouf Ahmed Ra’Ouf Ahmed

Theses

The goal of this work was to improve the performance of TiO2 nanomaterials by increasing their optical activities by shifting the onset of the response from the UV to the visible-light region. Among the several ways to achieve this goal, doping TiO2 nanomaterials with other elements (e.g. metals) was selected to narrow the band gap and enhance the optical properties of TiO2 nanomaterials. In this work, we have prepared Cu-doped TiO2 and Ag-doped TiO2 nano-catalysts, characterized them and studied their properties, and the optical ones in particular. The Ag-doped TiO2 catalyst was prepared by the sol-gel method while the Cu-doped …

Modeling Of Environmentally Assisted Fatigue Crack Growth Behavior, Sree Phani Chandar Reddy

Dissertations

The formation of fatigue cracks and their propagation due to cyclic loading in metals have been a concern for more than hundred years. Since fatigue failure were first reported by the railroad industry in 1840s, tremendous progress has been achieved in understanding fatigue behavior of metals. But fatigue damage is still a concern due to its complex dependency on various environmental variable like humidity, temperature, time and corrosive environment. Although numerous theories and models have been proposed in the past, the effects of environment on fatigue crack growth (FCG) is not completely understood. This dissertation aims to shed light on …

A Collaborative Conceptual Aircraft Design Environment For The Design Of Small-Scale Uavs In A Multi-University Setting, Joseph Samuel Becar

Theses and Dissertations

In today's competitive global market, there is an ever-increasing demand for highly skilled engineers equipped to perform in teams dispersed over several time-zones by geography. Aerospace Partners for the Advancement of Collaborative Engineering (AerosPACE) is a senior design capstone program co-developed by academia and industry to help students develop the necessary skills to excel in the aerospace industry by challenging them to design, build, and fly an unique unmanned aerial vehicle (UAV). Students with little to no experience designing UAVs are put together in teams with their peers from geographically dispersed universities. This presents a significant challenge for the students …

Dynamic Response Of A Multi-Span Curved Beam From Moving Transverse Point Loads, Amanda Alexander

HIM 1990-2015

This thesis describes how to evaluate a first-order approximation of the vibration induced on a beam that is vertically curved and experiences a moving load of non-constant velocity. The curved beam is applicable in the example of a roller coaster. The present research in the field does not consider a curved beam nor can similar research be applied to such a beam. The complexity of the vibration of a curved beam lies primarily in the description of the variable magnitude of the moving load applied. Furthermore, this motion is also variable. This thesis will present how this beam will displace …

Understanding And Modeling Pathways To Thrombosis, John Seligson

HIM 1990-2015

This research will investigate techniques to create a sensor that is responsive to methane at 23°C. The approach will use the integration of a very thin film, which changes its resistive properties when methane gas is applied, deposited atop the surface of a piezoelectric substrate. An aluminum thin film interdigital transducer will launch a surface acoustic wave (SAW) that travels under the sensor’s gas-sensitive resistive thin film. The SAW/resistive film interaction changes the SAW amplitude, phase and delay. For this work, three films, tin dioxide (SnO2), zinc oxide (ZnO) and palladium (Pd) [1, 2] will be studied. Gas detection will …

Frequency-Domain Faraday Rotation Spectroscopy (Fd-Frs) For Functionalized Particle And Biomolecule Characterization, Richard Murdock

HIM 1990-2015

In this study, the magnetically-induced vibrations of functionalized magnetic particle suspensions were probed for the development of a novel optical spectroscopy technique. Through this work (1) the frequency-dependence of the faraday rotation in ferrofluids and (2) the extension of this system to elucidating particle size and conformation as an alternative immunossay to costly and labor/time intensive Western Blotting and ELISA has been shown. With its sensitivity and specificity, this method has proven to be a promising multi-functional tool in biosensing, diagnostic, and therapeutic nanomedicine efforts. Due to its ubiquitous nature in all optically-transparent materials, the farady rotation, or circular birefringence, …

A Mechanics-Based Approach For Putt Distance Optimization, Pascual Santiago-Martinez

HIM 1990-2015

Quantifying the core mechanics of putting is imperative to developing a reliable model that predicts post-collision ball behavior. A preliminary model for the stroking motion of putting and putter-ball collision is developed alongside experiments, establishing an empirical model that supports the theory. The goal of the present study is to develop a correlation between the backstroke of a putt, or the pre-impact translation of the putter, and the post-impact displacement of the golf ball. This correlation is subsequently utilized to generate an algorithm that predicts the two-dimensional ball trajectory based on putt displacement and putting surface texture by means of …

Design And Evaluation Of A Test Platform For Thermal Mechanical And Acoustical Loading, Abdi Jasmin

HIM 1990-2015

Next generation hypersonic cruise vehicle components will be subjected to a collection of loads not achievable in contemporary mechanical test platform. The purpose of this thesis is to demonstrate the design of a unique test platform for combined extreme environment (P-CEEn) needed to replicate thermal, acoustic and mechanical loading to be imparted on hypersonic fuselage panels. The panels are typically subjected to super-imposed cycling from hypersonic shock/impingement and aerodynamic pressure from the usual ascent-cruise-decent motion of the aircrafts combined with mechanical vibration at acoustic frequencies; moreover, these slender components will undergo conventional mechanical fatigue with compressive mean stress due to …

Examination Of Heat Flux Through A Surface Using Digital Image Processing Of Infrared Images, Nicholas D. True

Honors Theses

The task for this project was to design and construct a system that could be used to examine heat transfer through a surface by analyzing images produced using thermal imaging cameras. A long rectangular box made of pinewood was constructed and a light bulb was inserted to provide a heating element. The front face of the box was made to be interchangeable so that various materials could be tested. Two Flir I5 thermal imaging cameras were used to take pictures of both sides of the front face at specific time intervals in order to determine the temperature distribution of the …

A Participatory Design Framework For Customisable Assistive Technology, Pearl O'Rourke

Doctoral

High product costs and device abandonment negatively affect people with disabilities who require Assistive Technology (AT), and poor product design is a root cause. The purpose of this research is to develop and demonstrate a participatory design framework for customisable AT, which addresses the need for low-cost assistive products that satisfy a broad range of consumers’ needs. This framework addresses two main gaps in the literature. First, user involvement in the design process of medical and rehabilitative products helps create products that are more effective but, although methods to involve users exist, there are currently scant techniques to translate the …

Controller Area Network (Can) Bus J1939 Data Acquisition Methods And Parameter Accuracy Assessment Using Nebraska Tractor Test Laboratory Data, Samuel E. Marx

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Electronics have become a standard in agricultural equipment and the trend of “smarter” equipment is on the rise. To have “smarter” equipment, a working knowledge of the accuracy of the data being transmitted throughout that equipment is needed. The controller area network (CAN) bus is the current interface to machine operation data transmitted between electronic control units (ECUs).

Because CAN bus has been around for nearly thirty years, numerous devices have been created for interfacing with the bus. Choosing a device can be a challenge, especially without knowing if there are differences between the logging methods for true data representation. …

Comparison Of Evaluation, Measurement & Verification Processes: Arkansas To Bordering States, William Burgess Carlisle

Mechanical Engineering Undergraduate Honors Theses

The purpose of this paper is to compare Evaluation, Measurement, and Verification (EM&V) standards established by Arkansas and surrounding states. EM&V is the process to quantify the energy savings of an energy management project. This paper details the rules and regulation regarding the EM&V proceedings required by investor-owned utilities in providing energy-saving projects. By comparison of each state’s requirement, a clear understanding is found on where Arkansas stands in maturity of its program requirements. The reader will find Arkansas on the forefront of EM&V standardization that represents a model that surrounding states are striving to emulate.

Gui Matlab Code To Display Damped, Undamped, Forced And Unforced Mass Spring Systems, Melanie Garcia

Mechanical Engineering Undergraduate Honors Theses

Machine Dynamics and Control is the course offered at the University of Arkansas that deals with damped, undamped, forced and unforced systems. It’s important for students to understand each of these systems for future implementation in the industry and daily real life situations. The three types of damped systems, underdamped, overdamped and critically damped are analyzed in this thesis. As well as only two of the most common forced functions are analyzed, the cosine and sine functions. The objective of this thesis was to develop a GUI code in Matlab that would help students visualize the differences between undamped, damped, …

Ligament Model Fidelity In Finite Element Analysis Of The Human Lumbar Spine, Mitchell Scott Hortin

Theses and Dissertations

The purpose of this project is to quantify the effects of increasing spinal ligament fidelity on the mechanics of the human lumbar spine using finite element analysis (FEA). In support of this goal, a material characterization study was completed to provide anisotropic, nonlinear material parameters for the human anterior longitudinal ligament. (ALL). Cadaveric samples of the human ALL were tested using a punch test technique. Multi- axial force-deformation data were gathered and fit to a commonly used transversely isotropic material model using an FEA system identification routine. The resulting material parameters produced a curve that correlated well with the experimental …

Globally Consistent Map Generation In Gps-Degraded Environments, Paul William Nyholm

Theses and Dissertations

Heavy reliance on GPS is preventing unmanned air systems (UAS) from being fully inte- grated for many of their numerous applications. In the absence of GPS, GPS-reliant UAS have difficulty estimating vehicle states resulting in vehicle failures. Additionally, naively using erro- neous measurements when GPS is available can result in significant state inaccuracies. We present a simultaneous localization and mapping (SLAM) solution to GPS-degraded navigation that al- lows vehicle state estimation and control independent of global information. Optionally, a global map can be constructed from odometry measurements and can be updated with GPS measurements while maintaining robustness against outliers.We detail …

Concurrent Engineering Through Parallelization Of The Design-Analysis Process, Eric Joseph Wardell

Theses and Dissertations

The disconnect between the way CAD and analysis applications handle model geometry has long been a hindrance to engineering design. Current industry practices often utilize outdated forms of geometry transfer between these different engineering software applications such as neutral file formats and direct translations. Not only to these current practices slow the engineering design process but they also hinder the integration of design and analysis programs.This thesis proposes a new, multi-user, integrated design-analysis architecture which allows auxiliary functions such as analysis and computer-aided manufacturing to be better connected with the computer-aided design. It is hypothesized that this new architecture will …

The Integration Of Heat Resources In A Solar Thermal-Heat Pump Hydronic System, John Degrove

Purdue Polytechnic Masters Theses

According to the U.S. Department of Energy, roughly 41% of the energy consumed in the U.S. is used the power buildings. Within that number, almost half is used to heat or cool the building. Current technologies allow for consistent thermal management, but most utilize energy harvested from fossil fuels or convert electricity back into thermal energy. Background literature shows that the utilization of alternative heat resources such as heat pumps and solar thermal collectors can greatly reduce the energy used for heat delivery while producing adequate heating performance. A combined hydronic system using a bank of solar thermal collectors in …

Experimental And Analytical Study Of An Open Cathode Polymer Electrolyte Membrane Fuel Cell., Alex Martin Bates

Electronic Theses and Dissertations

In this thesis four different fuel cell designs were simulated with consideration for electrochemical effects, reactant species transport, and heat transfer. Simulation results include the mass fraction of hydrogen, oxygen, and water, temperature gradient, pressure gradient, and velocity profile. One of the fuel cell designs was experimentally tested using two different membrane electrolyte assemblies; one high performance and the other high durability. The polarization curve resulting from simulation compares well with the polarization curve produced by experimental work. A 16 cell fuel cell stack was simulated with consideration for stack compression. The same fuel cell stack was tested experimentally for …

Vanadium Trichloride Thermochemical Solar Energy Storage System Analysis., Caleb Michael Rogers

Electronic Theses and Dissertations

As annual energy consumption grows, developing renewable solar energy conversion systems, storage systems, and high density electrical energy production systems is growing increasingly important. The proposed system utilizes vanadium trichloride thermal decomposition to produce chlorine gas and vanadium dichloride. A second reaction combines gaseous hydrogen chloride and the product vanadium dichloride to reform vanadium trichloride and produce hydrogen gas. Hydrogen gas and chlorine gas can be stored indefinitely and electrical energy is obtained from the chemicals by a non-humidified dry membrane hydrogen – chlorine fuel cell. The fuel cell produces the gaseous hydrogen chloride needed to reform vanadium trichloride. The …

Binding Innovation Technologies, Restoring Freedom To The World Of Snowboard Bindings, Matthew Lee Munsee

Undergraduate Honors Capstone Projects

Snowboarding technology has progressed by leaps and bounds since the sport's inception in the 1980's. However, there is one area that has gotten progressively worse. That area is flexibility and freedom of expression. In order to make the sport safer, the industry responded by making stiffer boots and bindings. Our goal is to bring back the high level of flexibility that built the sport while maintaining or exceeding current safety standards. We also need to reduce heel side shock so as to increase the comfort of the rider. Our design consists of three major systems that drastically increase flexibility, safety, …

Aerodynamic Flow Field Characterization Of Airfoils With And Without Leading Edge Modifications, Oscar Hernandez

Theses and Dissertations - UTB/UTPA

Recently, much focus has been on comprehending the aerodynamic properties associated with the humpback whales pectoral fin. The perturbations found on its leading edge are believed to attribute to the humpbacks maneuverability significantly. These tubercles are assumed to be analogous to strakes on an aircraft, which generate large-scale vortices. More specifically, the vortices prompted by the leading edge increase the momentum exchange within the boundary layer, allowing the flow to remain attached at higher angles of attack, thus delaying stall and in turn increase lift by a passive means of reducing drag. The focus of this investigation is on characterizing …

An Automated Method For Hot-To-Cold Geometry Mapping, Brandon Levi Doolin

Theses and Dissertations

An Automated Method for Hot-to-Cold Geometry Mapping.

An Investigation Of Off-Design Operation In High Suction Performance Inducers, Ryan Collins Cluff

Theses and Dissertations

Three-dimensional two-phase unsteady CFD simulations were run on three and four-blade inducers for the purpose of analyzing differences in cavitation stability at design and off-design flow rates. At design flow rates, there were very small differences between the breakdown curves for the three and four-bladed inducers. However, at lower cavitation numbers, the three-bladed inducer exhibited up to three times the rotor forces than the four-bladed inducer. When moving to off-design flow rates, both inducers experienced multiple modes of cavitation instabilities including rotating cavitation, alternate-blade cavitation, and cavitation surge. The four-bladed inducer began experiencing the formation of these modes of instability …

Use Of Direct Metal Laser Sintering For Tooling In High Volume Production, Joel W. Hendrickson

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

Metal 3D printing has caught the attention of many large industries. There have been stories of great success using metal 3D printing. Some of the largest industries to successfully use metal 3D printing are aerospace and medical. These industries have succeeded with metal 3D printing because of their need for light and complex parts. These success stories lead other industries to investigate how metal 3D printing or Direct Metal Laser Sintering (DMLS) can help them. Industries that are involved in high volume production ask how they can take advantage of the complexity and customization that is available with 3D printing. …

Extensions Of High-Order Flux Correction Methods To Flows With Source Terms At Low Speeds, Jonathan L. Thorne

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Computational Fluid Dynamics (CFD) is an attempt to mimic the physical world of fluids around us. In general, CFD simulations are completed by first making a mesh. Meshes are made of polygons that are arranged in such a way as to create the item in question and the fluid around it. There are many difficulties associated with mesh generation, and it can take days or weeks for a trained professional to produce adequate meshes. The CFD algorithms affect the accuracy of the simulation. Using high-order methods, more accurate results can be achieved than otherwise possible. Flux correction (FC) is a …

The Design, Build, And Validation Of A Hybrid Tower Used To Conduct Helmet Impact Tests, Darren Benn

UNLV Theses, Dissertations, Professional Papers, and Capstones

The National Operating Committee on Standards for Athletic Equipment (NOCSAE) was established to enlist research directed towards the reduction of head injuries in organized sports. The function of the test methods developed by NOCSAE is to provide the blueprint for reliable and repeatable procedures to measure the evaluation of various types of protective sports headgear and projectiles. In addition, the methods also govern hardware such as testing apparatus and data acquisition instrumentation. In helmet testing, the method dictates whether the impact is induced by a projectile system or by a drop tower system with an anvil at the base. Altogether, …

Development Of A Surrogate Bruising Detection System To Describe Potential Bruising Patterns Associated With Common Childhood Falls., Raymond Dsouza

Electronic Theses and Dissertations

Child abuse is a leading cause of fatality in children aged 0-4 years. An estimated 1,700 children die annually as a result of child abuse of which threequarters (75.7%) of the children were younger than 4 years old1. Infants (younger than 1 year) had the highest rate of fatalities among the group. Many of the serious injuries and fatalities could have potentially been prevented if clinicians and child protective services were able to better distinguish between injuries associated with abuse versus those caused by accidents. Missed cases of child abuse have been shown to be as high as 71% of …

Bi-Stable Buckled Energy Harvesters Actuated Via Torque Arms., Daniel Allen Porter

Electronic Theses and Dissertations

Vibrational energy harvesters (VEH) are one way to generate electricity. Though the energy quantities are not enough to run desktop computers, they can power remote devices such as temperature, pressure, and accelerometer sensors or power biological implants. New versions of the Bluetooth protocol can even be used with VEH technology to send wireless data. An important aspect of VEH devices is the power output, operating frequency, and bandwidth. This dissertation investigates a novel method of actuating the primary buckled energy harvesting structure using torque arms as a force amplification mechanism. Buckled structures can exhibit snap-through and has the potential to …