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Full-Text Articles in Mechanical Engineering

Design Of Machine Tool Cross Beam Using Metal Big Area Additive Manufacturing, Tyler Poon Aug 2023

Design Of Machine Tool Cross Beam Using Metal Big Area Additive Manufacturing, Tyler Poon

Masters Theses

The modern world would not be what it is now without machine tools. Advances in materials and processes, such as carbon fiber and additive manufacturing (AM), enable the design space for machine tool components to expand. However, machine tool components require accurate geometry, which is not available from parts produced by metal Big Area Additive Manufacturing (mBAAM). This project outlines the process in which a traditionally manufactured machine tool component, a welded box structure on an existing machine tool, was redesigned to be made using mBAAM. The goal was to design a structure that was printable using the MedUSA system …


Method Of Embedded Imperfections For The Direct Simulation Of Deformation Instabilities In Film-Substrate Structures, Siavash Nikravesh Kazeroni Apr 2022

Method Of Embedded Imperfections For The Direct Simulation Of Deformation Instabilities In Film-Substrate Structures, Siavash Nikravesh Kazeroni

Mechanical Engineering ETDs

In this dissertation, a novel finite-element methodology called “embedded imperfections” is proposed and employed for computationally simulating various types of deformation instabilities observed in film-substrate structures subjected to mechanical loading. The approach involves the incorporation of elements having distinctive material properties within the film-substrate interface. One can interpret this practice as a deliberate distribution of material defects within the numerical model. It has been shown that embedded imperfections not only can trigger the onset of instability, but also can lead to “direct” simulation of deformation instability problems in that primary and subsequent instability modes can all be captured in a …


Optimized Tip Cooling Using Am Process, Alberto H. Gamez, Lourdes Sarmiento Martinez, Andrew Van Bogelen Dec 2021

Optimized Tip Cooling Using Am Process, Alberto H. Gamez, Lourdes Sarmiento Martinez, Andrew Van Bogelen

Mechanical Engineering

This Final Design Review (FDR) reports on the senior design project undertaken by our team of mechanical engineering seniors at California Polytechnic State University, San Luis Obispo. This project seeks to use the additive manufacturing process to improve the existing design of a Taurus 60 gas turbine injector tip. The current injector tip is owned by Solar Turbines, a designer and manufacturer of gas turbines for electric generation, propulsion, as well as natural resource transportation. The challenge at hand is to design a new injector tip that will be reliable for at least 60,000 hours and provide ease of replacement, …


Mechanical Interfacial Locking And Multiscale Modeling Of Reinforced Thermoplastic Composites For Structural Applications, Anmol Kothari Dec 2021

Mechanical Interfacial Locking And Multiscale Modeling Of Reinforced Thermoplastic Composites For Structural Applications, Anmol Kothari

All Dissertations

The ever-growing pressure of reducing the adverse impact of transportation systems on environment has pushed industries towards fuel-efficient and sustainable solutions. While several approaches have been used to improve fuel efficiency, the light-weighting of structural components has proven broadly effective. In this regard, reinforced thermoplastic composites (RTPC), owing to their high recyclability, higher impact strength and fast cycle times, have become competitive candidates at an industrial scale. However, to implement RTPC toward large scale structural applications several challenges pertaining to material design and manufacturing effects need to be addressed. To this end, a computational study is carried out to address …


A Manufacturing-To-Response Pathway For Formed Carbon Fiber Reinforced Polymer Composite Structures, Madhura Limaye Aug 2021

A Manufacturing-To-Response Pathway For Formed Carbon Fiber Reinforced Polymer Composite Structures, Madhura Limaye

All Theses

Over the past decade, there has been an increased adoption of thermoplastic and thermoset based continuous carbon fiber reinforced polymer (CFRP) composites for structural applications in several industries. Among the different manufacturing methods, thermoforming process for thermoplastic based continuous CFRP’s offer a major advantage in reducing cycle times for large scale productions. Similarly, out-of-autoclave curing process for thermoset based continuous CFRP’s using heated tooling enables production of large composite structures. However, these manufacturing processes can have a significant impact on the structural performance of parts by inducing undesirable effects. These effects include inhomogeneous fiber orientations, thickness variations, and residual stresses …


Methodology For Analyzing Epoxy-Cnt Phononic Crystals For Wave Attenuation And Guiding, Madhu Kolati Jan 2016

Methodology For Analyzing Epoxy-Cnt Phononic Crystals For Wave Attenuation And Guiding, Madhu Kolati

Dissertations, Master's Theses and Master's Reports

Phononic crystals (PhnCs) control, direct and manipulate sound waves to achieve wave guiding and attenuation. This dissertation presents methodology for analyzing nanotube materials based phononic crystals to achieve control over sound, vibration and stress mitigation. Much of the analytical work presented is in identifying frequency band gaps in which sound or vibration cannot propagate through these PhnCs. Wave attenuation and mitigation analysis is demonstrated using finite element simulation. Engineering principles from current research areas of solid mechanics, solid-state physics, elasto-dynamics, mechanical vibrations and acoustics are employed for the methodology. A considerable effort is put to show that these PhnCs can …


Simulation Of An Oxidizer-Cooled Hybrid Rocket Throat: Methodology Validation For Design Of A Cooled Aerospike Nozzle, Peter Alexander Brennen Jun 2009

Simulation Of An Oxidizer-Cooled Hybrid Rocket Throat: Methodology Validation For Design Of A Cooled Aerospike Nozzle, Peter Alexander Brennen

Master's Theses

A study was undertaken to create a finite element model of a cooled throat converging/diverging rocket nozzle to be used as a tool in designing a cooled aerospike nozzle. Using ABAQUS, a simplified 2D axisymmetric model was created featuring only the copper throat and stainless steel support ring, which were brazed together for the experimental test firings. This analysis was a sequentially coupled thermal/mechanical model. The steady state thermal data matched closely to experimental data. The subsequent mechanical model predicted a life of over 300 cycles using the Manson-Halford fatigue life criteria. A mesh convergence study was performed to establish …