Mechanical Engineering Commons^™

The Analysis Of Mechanical Exfoliation Of Graphene For Various Fabrication And Automation Techniques, Lance Yarbrough

Mechanical Engineering Undergraduate Honors Theses

Mechanical Exfoliation of Graphene is an often-overlooked portion of the fabrication of quantum devices, and to create more devices quickly, optimizing this process to generate better flakes is critical. In addition, it would be valuable to simulate test pulls quickly, to gain insight on flake quality of various materials and exfoliation conditions. Physical pulls of graphene at various temperatures, pull forces, and pull repetitions were analyzed and compared to the results of ANSYS simulations, solved for similar results. Using ANSYS’ ability to predict trends in exfoliations, flake thickness and coverage using stress and deflection analyses were investigated. Generally, both strongly …

Stress Relaxation Cracking In 347h Austenitic Steel Weldments Under Various Heat Treatments: Experiments And Modeling, Yi Yang

Doctoral Dissertations

347H austenitic stainless steel exhibits exceptional creep and corrosion resistance, rendering it an exemplary candidate for pipeline materials, particularly in mid- to high-temperature working conditions. However, due to constraints in component dimensions, welding has been chosen as the preferred method for joining pipeline systems extensively employed in nuclear power plants, fossil fuel plants, and petrochemical companies. The welding process entails the accumulation of residual stress during the cooling stage, along with the introduction of microstructure evolution. Moreover, the residual stress field and microstructure continuously evolve under service conditions, thereby intensifying the susceptibility of crack initiation and propagation. The initial residual …

Estimated Aerodynamic Forces And Moments And Optimal Orientation Of The V-Bat Airframe During Vertical Landing In Gusty Conditions, Parker C. Carter

All Graduate Theses and Dissertations, Fall 2023 to Present

Ship based Unmanned Air Systems (UAS) are an important tool used by the United States Navy for situational awareness and short-range operations. Naval UAS are used to provide real-time intelligence, surveillance, reconnaissance, and target-acquisition while being low cost, mission flexible, and safe. Unfortunately UAS suffer disadvantages with respect to adverse environmental conditions caused by the air being displaced by the ship. The accumulation of one or more adverse conditions is known as airwake. To counteract the effects of airwake, the objectives of this work are to first evaluate the effect of forces and moments during the vertical landing phase of …

A One-Dimensional Analysis Of A Microbial Fuel Cell For Efficient Acetate Removal And Power Density Output, David Rouhani

UNLV Theses, Dissertations, Professional Papers, and Capstones

Microbial fuel cells (MFCs) are electrochemical devices that utilize microorganisms to convert organic matter into electrical energy. MFCs have been discussed to have potential application for sustainable wastewater treatment due to their ability to generate electricity while simultaneously treating contaminated water. To optimize MFC performance, numerical models can be used to understand the complex electrochemical and biological processes occurring in the system. In this study, a numerical model was developed to simulate the performance of MFCs under varying operating conditions and to investigate the performance of a MFC for treating wastewater fuel. More specifically, the MFC was modeled to oxidize …

Modeling, Simulation And Control Of Microrobots For The Microfactory., Zhong Yang

Electronic Theses and Dissertations

Future assembly technologies will involve higher levels of automation in order to satisfy increased microscale or nanoscale precision requirements. Traditionally, assembly using a top-down robotic approach has been well-studied and applied to the microelectronics and MEMS industries, but less so in nanotechnology. With the boom of nanotechnology since the 1990s, newly designed products with new materials, coatings, and nanoparticles are gradually entering everyone’s lives, while the industry has grown into a billion-dollar volume worldwide. Traditionally, nanotechnology products are assembled using bottom-up methods, such as self-assembly, rather than top-down robotic assembly. This is due to considerations of volume handling of large …

Improving Future Vehicle Fuel Economy And Operational Design Domain Through Novel Data Pipelines, Kyle James Carow

Masters Theses

Modern automobiles have greatly advanced in recent years, with technological developments that enhance performance, safety, and comfort. However, there is still much room for improvement. Today’s vehicles are heavily reliant on the combustion of fossil fuels, proven to be harmful for the environment on both a local and global scale. In addition, the safety benefits of autonomous vehicles and advanced driver assistance systems are not yet fully realized due to the limited operational design domain of these technologies. In this research, these needs are addressed through the development of two novel data pipelines. In the first study, a novel methodology …

Dynamic Mode Decomposition Approach For Estimating The Shape Of A Cable, Yash Manik Chavan

Dissertations, Master's Theses and Master's Reports

This study investigates the dynamic behavior of a flexible cable with heterogeneous stiffness using a data-driven approach. The study aims to develop accurate models describing intricate structures with rigid or flexible components. To achieve this, reflective markers were attached to the cable at equal spacing, and the motion was manually excited and captured using an 8-camera setup and OptiTrack's Motive software.

The cable displacement data at the marker locations were used as initial conditions for various Dynamic Mode Decomposition (DMD) models. The performance of the data- driven cable model is compared against the performance of the DMD modeling approach, fitting …

Acausal Modeling Of Wind Turbines With Validation And Control Studies, Kazi Ishtiak Mohsin

Graduate Thesis and Dissertation 2023-2024

This thesis involves the modeling, validation, and control studies of a Control-Oriented, Reconfigurable, and Acausal Floating Turbine Simulator (CRAFTS), that is currently under development. CRAFTS uses Modelica®, an object-oriented, declarative, multi-domain modeling language for physical system modeling in the Dymola environment. The CRAFTS simulator facilitates rapid dynamic simulation of wind turbines with various model variants and enables control co-design.

A major emphasis of this thesis is in the validation of the CRAFTS simulator for a 15-MW land-based wind turbine through several test cases. These test cases were collaboratively developed in conjunction with other participating research entities. CRAFTS has undergone rigorous …

Supporting Us Army Next-Generation Ground Vehicle Simulation Modeling Using An Integrated Ontology Suite, Edward Louis

All Theses

The development of the US Army’s next-generation of ground vehicle systems is supported by simulations that predict vehicle performance and inform engineering design choices in the design and acquisition process. In this paper, we describe the development of an Integrated Ontology Suite to support modeling and simulation of next generation military ground vehicles. The ontology suite is intended to address model reuse challenges and increase the shared understanding of ground vehicle system simulations. It is intended to function in a Model Library structure that stores, documents, assembles, and executes vehicle simulations. The ontology suite consists of four domain ontologies: Vehicle …

Eagle Medical Tray Denesting & Debris Removal Process, Nicholas Allen Ungefug, Noah Chavez, Susana Shu-Lin Okhuysen, Michael Augustine Pennington

Industrial and Manufacturing Engineering

Eagle Medical Incorporated is a contract medical device packaging and sterilization company. The company purchases thermoformed medical packaging trays, which maintain the sterility of medical devices, from various manufacturers. To ensure packaging quality and to prevent cleanroom contamination, Eagle Medical inspects and sterilizes each blister tray that they order. This process is an essential non-value-added activity that creates a bottleneck. Cleanroom employees must stop packaging medical devices and attend to the processing of blister trays and packaging solutions. The blister trays arrive at Eagle’s facility in nested stacks. Vibration and movement during shipping further compresses the stacks, which makes separation …

Therapeutic Mechanical Horse, Cade M. Liberty, Aleya Dolorfino, Peter Philips, Zuzanna Dominik, Luke Watts

Mechanical Engineering

Jack's Helping Hand and its hippotherapy participants required a device to serve as an alternative to a live horseback riding experience that could also increase the range of riders. This would provide more clients with equine-assisted therapy that has proven to better the lives of people with both physical and mental disabilities. Horses can be unpredictable, tall, and sometimes anxiety-inducing, especially for new riders. Our group’s aim was to develop a mechanical horse that will be able to reduce these issues for equine therapy centers and the riders they help. When a rider gets to practice sitting on the horse …

Characterizing Mechanical Regulation Of Bone Metastatic Breast Cancer Cells, Boyuan Liu

Doctoral Dissertations

Breast cancer most frequently metastasizes to the skeleton. Bone metastatic cancer is incurable and induces wide-spread bone osteolysis, resulting in significant patient morbidity and mortality. Mechanical stimuli in the skeleton are an important microenvironmental parameter that modulates tumor formation, osteolysis, and tumor cell-bone cell signaling, but which mechanical signals are the most beneficial and the corresponding molecular mechanisms are unknown. This work focused on bone matrix deformation and interstitial fluid flow based on their well-known roles in bone remodeling and in primary breast cancer. The goal of our research was to establish a platform that could define the relationship between …

Thermal And Mechanical Numerical Modeling Of Extrusion-Based 3d Printed Reinforced Polymers For Selecting Manufacturing Process Parameters, Sunil Bhandari

Electronic Theses and Dissertations

Extrusion-based 3D printing of thermoplastic polymer composites manufactures parts that have nonhomogenous, orthotropic, and process-dependent macro-scale material properties. As a part of the dissertation, research works were carried out to: • improve the interlayer mechanical properties and reduce the orthotropy, • use experimentally homogenized orthotropic material properties to numerically model the mechanical behavior of the non-homogenous orthotropic 3D printed parts, • create an efficient numerical thermal model to predict the process-dependent thermal history of the 3D printed part, and • aid the manufacturing process by selecting a suitable set of processing parameters based on a simplified sequentially coupled thermomechanical model. …

Nonlinear Model Development And Validation For Ball And Plate Control System, Zachary Richter

Master's Theses

Ball and plate balancing control systems are commonly studied due to the complex dynamics associated with the instability of the system in open-loop. For simplicity, mathematical models describing the ball and plate dynamics are often linearized and the effects of complex motion are assumed to be negligible. These assumptions are rarely backed with evidence or explanations validating the simplified form of the dynamical equations of motion. This thesis focuses on developing a nonlinear model that more accurately defines the dynamics of the system, in order to quantify the error of linear and nonlinear models when compared to a Simscape physical …

Modeling And Control Of A Vertical Hopping Robot, Bradley Y. Kwan

Master's Theses

Single degree-of-freedom hopping robots are typically modeled as spring loaded inverted pendulums (SLIPs). This simplified model, however, does not consider the overall leg geometry, consequently making it difficult to investigate the optimized inertial distribution of the leg for agile locomotion. To address this issue, the first part of this thesis establishes an accurate mathematical model of a DC-motor-driven, two-link hopping robot where the motors are modeled as torque sources. The equations of motion for the two distinct phases of locomotion (stance and flight) are derived using the Lagrangian approach for holonomic systems. A Simulink/Stateflow model is developed to numerically simulate …

Computational Fluid Dynamics And Fluid Structure Interaction Research On Flow In A Glenn Shunt And A Flexible Tube And On A Cantilevered Plate, Chunhui Wang

McKelvey School of Engineering Theses & Dissertations

This thesis employs Computational Fluid Dynamics (CFD) simulation technology to solve three flow problems: (1) Blood flow in a Bidirectional Glenn Shunt and a combined Bidirectional Glenn Shunt (BGS) and Blalock-Taussing (BT) Shunt. This shunt is used to address the problem of Cyanosis or “Blue Baby Syndrome,” which is an infant disorder that affects the newly born babies whose skins turn blue or purple because of lack of necessary blood flow between heart and lung due to pulmonary vascular blockage. The goal of this study was to evaluate the performance of BGS and combined BGS+BT shunt in achieving the desired …

Development Of A Solidworks Simulation Toolkit For A Sophomore Level Biomedical Engineering Course, Jordan Crosby

Biomedical Engineering Undergraduate Honors Theses

In the engineering industry, computer-aided design (CAD) programs are used to create models and create virtual experiments or studies that allow engineers to observe the real behavior of parts or assemblies under certain conditions. Companies hire students with experience in CAD, as professionals believe that CAD experience is beneficial [1,2]. SolidWorks is among the most popular CAD software used by engineers. SolidWorks has multiple functionalities that also allow for finite element analysis dependent on the license. Users can create simulation studies in SolidWorks Simulation that can be used as an accurate approximation for real results.

The goal of this study …

Computational Study On Suppression Of Airfoil Flow Separation Using High-Frequency Translational Surface Actuation, Bibek Gupta

Honors Theses

Flow separation is a phenomenon that occurs when pressure increases in the streamwise direction of a flow, making a distinctive boundary layer or separation bubble. It causes aircraft to experience an increase in drag and noise and a decrease in a lift, hence degrading their aviation performance. This study uses numerical simulations to understand better the effects of high-frequency translational surface actuation (HFTSA) on flow separation control. The numerical simulations mimic the experimental parameters of an experiment performed by Okoye et al. on using the HFTSA system to control flow separation. A symmetrical airfoil structure of chord length of 0.3 …

Automated Scenario Generation Using Halton Sequences For The Verification Of Autonomous Vehicle Behavior In Simulation, Andrew Ferree

Doctoral Dissertations and Master's Theses

As autonomous vehicles continue to develop, verifying their safety remains a large hurdle to mass adoption. One component of this is testing, however it has been shown that it is impractical to statistically prove an autonomous vehicle’s safety using real-world testing alone. Therefore, simulation tools and other virtual testing methods are being employed to assist with the verification process. Testing in simulation still faces some of the challenges of the real world, such as the difficulty in exhaustively testing the system in all scenarios it will encounter. Manual scenario creation is time consuming and does not guarantee scenario coverage. Pseudo-random …

Finite Element Analysis Of Assembly For Warped Composite Automotive Components, Theogenes De Oliveira Maia

Electronic Thesis and Dissertation Repository

One of the most used processes in the automotive industry is the moulding of parts made of thermoplastics filled with glass fibres. This research focused on a specific material: long fibre thermoplastics (LFT). On the one hand, the performance gain, in terms of lightweight and the strength of final components, justifies its wide use. On the other hand, due to the intrinsic characteristics of part manufacturing, warpage is evident and can influence or even compromise subsequent stages of production.

This research has three main objectives: recreate in the most faithfully way, in Abaqus^TM environment, the conditions that precede the …

Equations Of State For Warm Dense Carbon From Quantum Espresso, Derek J. Schauss

Theses and Dissertations

Warm dense plasma is the matter that exists, roughly, in the range of 10,000 to 10,000,000 Kelvin and has solid-like densities, typically between 0.1 and 10 grams per centimeter. Warm dense fluids like hydrogen, helium, and carbon are believed to make up the interiors of many planets, white dwarfs, and other stars in our universe. The existence of warm dense matter (WDM) on Earth, however, is very rare, as it can only be created with high-energy sources like a nuclear explosion. In such an event, theoretical and computational models that accurately predict the response of certain materials are thus very …

Fluid-Structure Interaction For A Deformable Anisotropic Cylinder: A Case Study, Jared T. Decker

Honors Undergraduate Theses

For a structure designed to interact with the surrounding fluid, structural deformation under loads induced by fluid flows is an important factor to consider, and one which is traditionally difficult to account for analytically. Coupling the finite element method for structural analysis with the finite volume method for the determination of fluid response allows for accurate simulation of the pressure and shearing loads applied by the fluid onto the fluid-structure interface, while also determining localized structural displacements that would cause changes to the geometry of the interface. This work seeks to simulate the behavior of cylinders with varying heights and …

Development Of A Method To Model An Enclosed, Coaxial Carbon Nanotube Speaker With Experimental Validation, Suraj Prabhu

Dissertations, Master's Theses and Master's Reports

Carbon nanotube (CNT) speakers operate on heat as compared to conventional loudspeakers that operate on vibration. CNT speakers are extremely lightweight, stretchable, flexible, and have high operating temperatures. Due to these advantages, CNT speakers are being considered as a viable replacement option for conventional loudspeakers. One such application is automotive exhaust noise control. The goal of this research is to design an enclosed, coaxial CNT speaker and to develop a modeling method to model this speaker using COMSOL Multiphysics.

As part of this research, an enclosed, coaxial CNT speaker was designed and manufactured for automotive exhaust noise control. The first …

Formula Sae Design Validation Through Lap Time Simulation, Noah Gresser, Akos Jasper, Michael Metropoulos, Paul Buczynski, James Volcansek

Williams Honors College, Honors Research Projects

Lap time simulation is capable of advancing Zips Racing into a new, modern era for future vehicle designs. Through the use of VI-grade simulation software, Zips Racing was able to validate its current combustion and electric vehicle designs in spite of the challenges brought on to the team as a result of the COVID-19 pandemic. Throughout this project, the design team gained an enhanced understanding of suspension designs and optimizations through the usage of computer simulations. As a result, the teams have a better understanding of the fundamental changes that need to occur to enhance the race team’s final race …

Thermal Modeling And Analysis Of Roadway Embedded Wireless Power Transfer Modules, Arden N. Barnes

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Wireless charging of electric vehicles is a developing technology which potentially increases efficiency and safety. It also allows for charging vehicles while they are moving by having charging stations embedded in the roadway. Because roadways are thermally insulating, it is important to know how the heat from the charging stations will move through the roadway, which will allow further research into whether the heat will cause damage to the components in the station or to the roadway. This thesis studies the way the heat moves through concrete with wireless charging coils embedded in it. This is accomplished by measuring the …

Design For Additive Manufacturing, Michael Charonnat, Leonardo Franco-Muñoz, Sam Noble, J.P. Purdom

Mechanical Engineering

This document outlines the critical design details and timeline for the Design for Additive Manufacturing Senior Project sponsored by Solar Turbines, Inc. The scope of this project encompasses the redesign of two of Solar Turbine’s cast parts for metal additive manufacturing in order to minimize lead time, cost, and weight. With the overall objective of performing in-depth analysis exploring affordability & feasibility, this redesign process will aid Solar Turbines in expanding their knowledge of Design for Additive Manufacturing principles and enable them to further incorporate the use of additive manufacturing into their production processes. The first part that the team …

Discrete Vortex Modeling Of Aerodynamic Flutter Of A Flat Plate With Damped Oscillations, Emma Chao

UNLV Theses, Dissertations, Professional Papers, and Capstones

Aerodynamic flutter is the unstable oscillation of a body caused by the interaction of aerodynamic forces, structural elasticity, and inertial effects induced by vortex shedding. Current models of this phenomenon require finite element analysis and extensive computational power and processing time. The purpose of this study was to develop and validate a program that is faster and more efficient than existing approaches by using the discrete vortex method (DVM). By reducing the complexities of flutter to the shedding of vortices in an inviscid model of a two-dimensional flat plate with a torsional spring constant at its center, this phenomenon can …

Impact Of Magnetocaloric Material Properties On Performance Of A Magnetocaloric Heat Pump., Michael G. Schroeder

Electronic Theses and Dissertations

In the field of magnetocaloric heat pumps much research has been performed around machine design and theoretical machines, but little has been researched around practical problems such as variability in material properties. The present work defines a simulation tool that has been proven with experimental data. Magnetocaloric material cascades were statistically analyzed and parameterized, such that they could be recreated parametrically using a split Lorentz function with normally distributed parameters. Correlated curve-defining values with standard deviations were used as input into the simulation tool to determine the effect of variation on cooling heat pump performance for a household refrigerator application. …

Virtual Experiments For Engineering Education, Amy P. Lebanoff

Honors Undergraduate Theses

In-person engineering instruction relies on the availability of equipment and space. Cost, safety, and scheduling may pose barriers to conducting in-person labs. Virtual experiments may be used to enhance the student experience by, for example, incorporating pre-labs for in-person experiments and providing access to equipment that cannot be safely used in-person. Virtual learning is used in many fields, but there remain questions as to how it should be employed in engineering, an area largely reliant on in-person lab and classroom setups. Earlier studies reviewed the advantages of virtual labs such as demonstrating hard-to-observe phenomena and allowing unlimited trials. This project …

Modeling, Simulation, And Validation Of Process-Structure-Property Relationships In Fused Filament Fabrication, Aaron Grant

Electronic Theses and Dissertations

As additive manufacturing (AM) grows in popularity, the need for better simulation tools to predict the process-structure-property relationships of AM parts becomes ever more necessary to employ the technology in design of functional parts with varying degrees of complexity and performance requirements. Many simulation tools and techniques have been developed that aim to achieve this goal, and the main purpose of this research is to explore how well different simulation tools and modeling approaches can capture various AM-specific features such as inter-raster and end-of raster voids, and residual stresses induced by dissimilar rates of thermal expansion. Process simulation of fused …