Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 5 of 5
Full-Text Articles in Mechanical Engineering
Organic-Inorganic Graphite And Transition Metal Dichalcogenide Based Composites For 3d Printing, Jorge Alfredo Catalan Gonzalez
Organic-Inorganic Graphite And Transition Metal Dichalcogenide Based Composites For 3d Printing, Jorge Alfredo Catalan Gonzalez
Open Access Theses & Dissertations
This project was multipronged to help fuse together topics of additive manufacturing and two-dimensional (2D) layered materials, and studying the mechanical and electrical properties of the composites produced. The composites are made from the thermoplastic polymer acting as a matrix and the graphite and 2D transition metal dichalcogenides (TMDs) serving as the filler or reinforcement. Different concentrations of TMD's were added to the matrix to study the effect of composition on the mechanical and electrical properties. To shed insights into the mechanical properties, test coupons were produced as "dog bone" structures for tensile testing using the ASTM D638 type 5 …
Comprehensive Finite Element Modeling Of Ti-6al-4v Cellular Solids Fabricated By Electron Beam Melting, Edel Arrieta
Comprehensive Finite Element Modeling Of Ti-6al-4v Cellular Solids Fabricated By Electron Beam Melting, Edel Arrieta
Open Access Theses & Dissertations
Additive manufacturing permits the fabrication of cellular metals which are materials that can be highly customizable and possess multiple and extraordinary properties such as damage tolerance, metamorphic and auxetic behaviors, and high specific stiffness. This makes them the subject of interest for innovative applications. With interest in these materials for energy absorption applications, this work presents the development of nonlinear finite element models in commercial software platforms (MSC Patran/Nastran) that permit the analysis of the deformation mechanisms of these materials under compressive loads. In the development of these models, a detailed multiscale study on the different factors affecting the response …
Structural And Mechanical Characterization Of Nanocrystalline Tungsten And Tungsten-Based Alloy Thin Films For Extreme Environment Applications, Gustavo Martinez
Structural And Mechanical Characterization Of Nanocrystalline Tungsten And Tungsten-Based Alloy Thin Films For Extreme Environment Applications, Gustavo Martinez
Open Access Theses & Dissertations
Extreme environments associated with nuclear applications often results in degradation of the physical, mechanical and thermo-mechanical properties of the materials. Tungsten (W) exhibits unique physical and mechanical properties, which makes tungsten a good candidate for nuclear applications; however, intrinsic W exhibits low fracture toughness at all temperatures in addition to a high ductile to brittle transition. In the present work, nanocrystalline W, W-Y and W-Mo alloys were nanoengineered for nuclear applications. Nanocrystalline tungsten coatings with a thickness of ~1 µm were deposited onto Silicon (100) and Sapphire (C-plane) using RF and DC sputtering techniques under various growth conditions. Yttrium content …
Mechanically Activated Magnesiothermic Combustion Synthesis Of Zirconium And Hafnium Diborides, Sergio Cordova
Mechanically Activated Magnesiothermic Combustion Synthesis Of Zirconium And Hafnium Diborides, Sergio Cordova
Open Access Theses & Dissertations
Magnetohydrodynamic (MHD) generation of electric power has the potential to increase the thermal efficiency of fossil-fuel burning power plants. Electrode materials in MHD generators must possess a high melting point, high electrical and thermal conductivities, chemical stability, and resistance to thermal shock, oxidation, and plasma sparks/arcs. Ultra-high temperature ceramics based on diborides of zirconium and hafnium (ZrB2 and HfB2) are promising materials for this application. Self-propagating high-temperature synThesis (SHS) is an attractive method for their large-scale fabrication, but SHS of ZrB2 and HfB2 from elemental Zr, Hf, and B is not economically viable because of the high cost of the …
Test Methods For The Fracture And Fatigue Crack Growth Behavior Of Hot Mix Asphalts, Eduardo Garcia
Test Methods For The Fracture And Fatigue Crack Growth Behavior Of Hot Mix Asphalts, Eduardo Garcia
Open Access Theses & Dissertations
The service life and mechanical properties of bituminous mixtures are greatly affected by distress problems such as fracture, thermal cracking, and fatigue cracking of the asphalt layers. The fracture and fatigue crack growth (FCG) behavior of bituminous mixtures are difficult to quantify due to material-, test-, and equipment-related uncertainties. The goal of this study is to introduce a systematic fracture and fatigue crack growth testing approach for hot mix asphalts (HMAs). The objective is to experimentally evaluate the fracture resistance and fracture toughness behavior of a dense-graded HMA material at different temperatures and varying thicknesses. The effect of thickness on …