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Full-Text Articles in Mechanical Engineering
Equations Of State For Warm Dense Carbon From Quantum Espresso, Derek J. Schauss
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 …
Towards Better Understanding Of Failure Modes In Lithium-Ion Batteries: Design For Safety, Alex B. Francis
Towards Better Understanding Of Failure Modes In Lithium-Ion Batteries: Design For Safety, Alex B. Francis
Theses and Dissertations
In this digital age, energy storage technologies become more sophisticated and more widely used as we shift from traditional fossil fuel energy sources to renewable solutions. Specifically, consumer electronics devices and hybrid/electric vehicles demand better energy storage. Lithium-ion batteries have become a popular choice for meeting increased energy storage and power density needs. Like any energy solution, take for example the flammability of gasoline for automobiles, there are safety concerns surrounding the implications of failure. Although lithium-ion battery technology has existed for some time, the public interest in safety has become of higher concern with media stories reporting catastrophic cellular …
Real-Time Visualization Of Finite Element Models Using Surrogate Modeling Methods, Ryan C. Heap
Real-Time Visualization Of Finite Element Models Using Surrogate Modeling Methods, Ryan C. Heap
Theses and Dissertations
Finite element analysis (FEA) software is used to obtain linear and non-linear solutions to one, two, and three-dimensional (3-D) geometric problems that will see a particular load and constraint case when put into service. Parametric FEA models are commonly used in iterative design processes in order to obtain an optimum model given a set of loads, constraints, objectives, and design parameters to vary. In some instances it is desirable for a designer to obtain some intuition about how changes in design parameters can affect the FEA solution of interest, before simply sending the model through the optimization loop. This could …
Mathematical Model And Experimental Exploration Of The Nanoinjector Lance Array, Nathan C. Toone
Mathematical Model And Experimental Exploration Of The Nanoinjector Lance Array, Nathan C. Toone
Theses and Dissertations
The Nanoinjector Lance Array has been developed to inject foreign material into thousands of cells at once using electrophoresis to attract and repel particles to and from the electrically-charged lances. A mathematical computer model simulating the motion of attracted or repelled proteins informs the design of the nanoinjection lance array system. The model is validated by accurately predicting protein velocity in electrophoresis experiments. A complete analysis of parameters is conducted via simulations and specific research questions regarding the counter electrode of the nanoinjector lance array system are explored using the model. A novel technique for fabricating lance arrays from collapsed …
A New Eulerian-Based Double Continuity Model For Predicting The Evolution Of Pair Correlation Statistics Under Large Plastic Deformations, Sadegh Ahmadi
Theses and Dissertations
A new model using a double-continuity relation for predicting the evolution of pair-correlation functions (PCFs) is presented. The proposed model was developed using statistical continuum theory and is employed to predict the viscoplastic behavior of polycrystalline materials. This model was built based upon the continuity relations and a double divergence law that guarantees the conservation of both orientation and mass; and also satisfies the field equations (equilibrium, constitutive, and compatibility) at every point of the polycrystalline material throughout the deformation process. In the presented model, motion of particles in the real space and rotation of crystallographic orientations in the Euler …
Development Of A Methodology For Numerical Simulation Of A D C Arc Discharge In A Liquid Dielectric, Christopher James Lewis
Development Of A Methodology For Numerical Simulation Of A D C Arc Discharge In A Liquid Dielectric, Christopher James Lewis
Theses and Dissertations
The majority of literature regarding the numerical simulation of arc discharges in gaseous environments has used a plasma physics approach. Virtually all simulations treat the discharge as an idealized gaseous plasma, which can be described by temperature, pressure, and electric field. This approach can work well if the media is a shielding gas such as Argon; however, the approach does not work well for processes such as underwater welding, EDM, and underwater discharges used to generate high purity particles. The reason these discharges do not have many extensive simulation efforts as described in the literature is because they occur in …
Integrating Value Stream Mapping And Simulation, Michelle E. Scullin
Integrating Value Stream Mapping And Simulation, Michelle E. Scullin
Theses and Dissertations
An important principle in Lean manufacturing, value stream mapping (VSM) can be helpful in understanding how process flow and information flow affect each other. A VSM is a static picture of a process that allows the user to see where value is added into the value stream. Simulation is used to evaluate the behavioral issues of processes. In a manufacturing realm this means simulation shows how each operation affects other operations so determinations can be made about where bottlenecks or other problems exist in the process. Theoretically, the integration of VSM and Simulation can aide in process improvement by showing …
Development And Application Of A New Modeling Technique For Production Control Schemes In Manufacturing Systems, Bashar Hafez Sader
Development And Application Of A New Modeling Technique For Production Control Schemes In Manufacturing Systems, Bashar Hafez Sader
Theses and Dissertations
This dissertation presents dynamic system models of continuous manufacturing systems based on analogies with electrical systems. The developed modeling technique has the capability to explicitly specify production control schemes including control points, material and information flow paths, and logical operations. The model provides standard graphical representations and governing equations to describe both the steady state and transient responses of continuous manufacturing systems. For deterministic systems, these equations can be solved to get closed-form solutions. For stochastic systems, numerical solutions can be obtained for any probabilistic distribution. The electrical analogs provide an excellent tool to model control signals and logical operations. …
A Tool Wear Comparative Study In Turning Versus Computer Simulation In 1018 Steel, Woodrow D. Miner
A Tool Wear Comparative Study In Turning Versus Computer Simulation In 1018 Steel, Woodrow D. Miner
Theses and Dissertations
The material removal process uses cutting tools in order to produce the desired shape of the workpiece. Tool wear has been a problem for cutting tools, since cutting tools wear and break. Research has been accomplished in the tool wear field for tool life and more recently tool wear. The computer generation has created a method to simulate the material removal process. These computer simulations model the cutting tool reaction with the workpiece. Many of the simulation models use finite element analysis to calculate the reaction of the cutting tool. Different finite element models are being used throughout the world …
A Finite Element Simulation Of Temperature And Material Flow In Fricton Stir Welding, Mark J. Lasley
A Finite Element Simulation Of Temperature And Material Flow In Fricton Stir Welding, Mark J. Lasley
Theses and Dissertations
The purpose of this research was to use the Transvalor S.A. product, Forge3, to develop a finite element simulation of the friction stir welding process that improves the predictability of temperature evolution and material flow within the plunge portion of the process. Previous modeling created more heating within the billet than experimental results, probably due to the simplification of the simulation with adiabatic boundary conditions. More realistic tooling temperatures were included in this model as these affect heat evolution which is a determining factor in microcrystalline growth. These results were validated by experimental efforts using a billet and tooling instrumented …
The Benefit Of Using Simulation To Improve The Implementation Of Lean Manufacturing Case Study: Quick Changeovers To Allow Level Loading Of The Assembly Line, Jack J. Mcclellan
The Benefit Of Using Simulation To Improve The Implementation Of Lean Manufacturing Case Study: Quick Changeovers To Allow Level Loading Of The Assembly Line, Jack J. Mcclellan
Theses and Dissertations
In today's competitive manufacturing environment, companies are constantly looking for ways to improve. Because of this, many companies are striving to become "lean" by implementing lean manufacturing, which is a difficult process. To aid in the implementation of lean manufacturing, simulation was used to reduce the trial-and-error period of lean manufacturing and find to optimum approach to implement the lean manufacturing principle. In this research, a case study of implementing level loading of the production schedule for BullFrog International, L.C. will be examined. To make it possible to implement level loading, the thermo-former machine at the beginning of the operations …