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Full-Text Articles in Mechanical Engineering
Modelling, Sensing, And Control Of Weld Beads In Gravity Aligned And Non-Gravity Aligned Orientations For Wire Arc Additive Manufacturing, Joshua J. Penney
Modelling, Sensing, And Control Of Weld Beads In Gravity Aligned And Non-Gravity Aligned Orientations For Wire Arc Additive Manufacturing, Joshua J. Penney
Doctoral Dissertations
Wire Arc Additive Manufacturing (WAAM) has recently developed into a viable manufacturing process for large, complex metal parts. The WAAM process uses a Gas Metal Arc Welding (GMAW) torch mounted to an automated motion platform to execute a predetermined path plan based on a desired CAD geometry. As the desired geometry becomes more complex, it is advantageous to utilize out-of-position welding techniques used by human welders to stabilize the weld pool during the deposition of large overhangs. To ensure part accuracy and quality, adding layers of real-time control to manage various aspects of the WAAM process is critical. First, a …
Digital Cutting Force Modeling For Milling Operations, Timothy T. No
Digital Cutting Force Modeling For Milling Operations, Timothy T. No
Doctoral Dissertations
Process improvement in milling through improved understanding of machining dynamics is an on-going research endeavor. The objective of this project is to advance digital modeling of the milling process by incorporating tool-specific geometry in the machining analysis. Structured light scanning will be used to perform tool geometry measurements and produce a 3D model. The 3D model data will include the spatial location of the cutting edges, as well as the rake and relief profiles from the tool cross section. The rake and relief profiles will be imported, together with the work material flow stress model, into a finite element analysis …
Fundamental Studies Of Electrochemical Reactions And Microfluidics In Proton Exchange Membrane Electrolyzer Cells, Jingke Mo
Doctoral Dissertations
In electrochemical energy devices, including fuel cells, electrolyzers and batteries, the electrochemical reactions occur only on triple phase boundaries (TPBs). The boundaries provide the conductors for electros and protons, the catalysts for electrochemical reactions and the effective pathways for transport of reactants and products. The interfaces have a critical impact on the overall performance and cost of the devices in which they are incorporated, and therefore could be a key feature to optimize in order to turn a prototype into a commercially viable product. For electrolysis of water, proton exchange membrane electrolyzer cells (PEMECs) have several advantages compared to other …
Fully Coupled Fluid And Electrodynamic Modeling Of Plasmas: A Two-Fluid Isomorphism And A Strong Conservative Flux-Coupled Finite Volume Framework, Richard Joel Thompson
Fully Coupled Fluid And Electrodynamic Modeling Of Plasmas: A Two-Fluid Isomorphism And A Strong Conservative Flux-Coupled Finite Volume Framework, Richard Joel Thompson
Doctoral Dissertations
Ideal and resistive magnetohydrodynamics (MHD) have long served as the incumbent framework for modeling plasmas of engineering interest. However, new applications, such as hypersonic flight and propulsion, plasma propulsion, plasma instability in engineering devices, charge separation effects and electromagnetic wave interaction effects may demand a higher-fidelity physical model. For these cases, the two-fluid plasma model or its limiting case of a single bulk fluid, which results in a single-fluid coupled system of the Navier-Stokes and Maxwell equations, is necessary and permits a deeper physical study than the MHD framework. At present, major challenges are imposed on solving these physical models …