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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 …

Application Of Physically Based Semi-Distributed Hec-Hms Model For Flow Simulation In Tributary Catchments Of Kaohsiung Area Taiwan, Fiaz Hussain, Ray-Shyan Wu, Kai-Chun Yu

Journal of Marine Science and Technology

Hydrologic modeling is a commonly used tool to understand the rainfallerunoff processes of gauged and ungauged catchments for proper quantitative estimation of water resources availability. In the present study, an attempt is made to simulate surface runoff using a physically based semi-distributed hydrological (HEC-HMS) model for four local-scale tributary catchments of Kaohsiung area Taiwan. The input physical parameters of the model were calculated and preprocessed in HEC-GeoHMS based on digital elevation model (DEM), land use, soil and hydro-meteorological data. The model performance was satisfactory with Nash Sutcliffe Efficiency (NSE) ¼ 0.51 to 0.86 and the coefficient of determination (R2) ¼ …

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 …

Pore Microstructure Impacts On Lithium Ion Transport And Rate Capability Of Thick Sintered Electrodes, Ziyang Nie, Rohan Parai, Chen Cai, Charles Michaelis, Jacob M. Lamanna, Daniel S. Hussey, David L. Jacobson, Dipankar Ghosh, Gary M. Koenig Jr.

Mechanical & Aerospace Engineering Faculty Publications

Increasing electrode thickness is one route to improve the energy density of lithium-ion battery cells. However, restricted Li⁺ transport in the electrolyte phase through the porous microstructure of thick electrodes limits the ability to achieve high current densities and rates of charge/discharge with these high energy cells. In this work, processing routes to mitigate transport restrictions were pursued. The electrodes used were comprised of only active material sintered together into a porous pellet. For one of the electrodes, comparisons were done between using ice-templating to provide directional porosity and using sacrificial particles during processing to match the geometric density …