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Full-Text Articles in Engineering
Analyzing The Effects Of Ultrafast Laser Processing On Mechanical Properties Of 3d-Printed Pla Parts, Darshan Pramodbhai Yadav
Analyzing The Effects Of Ultrafast Laser Processing On Mechanical Properties Of 3d-Printed Pla Parts, Darshan Pramodbhai Yadav
Theses and Dissertations
Recent advances in additive manufacturing technologies have already led to wide-scale adoption of 3D-printed parts in various industries. The expansion in choice of materials that can be processed, particularly using Fused Deposition Modeling (FDM), and the steady advancements in dimensional accuracy control have extended the range of applications far beyond rapid prototyping. However, additive manufacturing still has considerable limitations compared to traditional and subtractive manufacturing processes. This work addresses limitations associated with the as-deposited surface roughness of 3D-printed parts. The effects of roughness-induced stress concentrations were studied on ultimate tensile strength and fatigue life. The samples were manufactured using a …
Searching Extreme Mechanical Properties Using Active Machine Learning And Density Functional Theory, Joshua Ojih
Searching Extreme Mechanical Properties Using Active Machine Learning And Density Functional Theory, Joshua Ojih
Theses and Dissertations
Materials with extreme mechanical properties leads to future technological advancements. However, discovery of these materials is non-trivial. The use of machine learning (ML) techniques and density functional theory (DFT) calculation for structure properties prediction has helped to the discovery of novel materials over the past decade. ML techniques are highly efficient, but less accurate and density functional theory (DFT) calculation is highly accurate, but less efficient. We proposed a technique to combine ML methods and DFT calculations in discovering new materials with desired properties. This combination improves the search for materials because it combines the efficiency of ML and the …
Strain Components In Friction Stir Extrusion, Megan Ryan
Strain Components In Friction Stir Extrusion, Megan Ryan
Theses and Dissertations
Friction stir extrusion is a solid state process that uses a rotating die to perform extrusions. This process can be used to directly recycle waste from machining processes and has been shown to produce wires with desirable mechanical properties. In order to better understand the friction stir extrusion process, the effect of the process parameters on the strain distribution in the wires needs to be understood. The process parameters evaluated in this work are die advance rate, die rotational seed, and die geometry. A total of 16 wires were extruded using different combinations of these process parameters. Marker wires were …
Structural Origin Of Mechanical Prowess In Conch Shells, Haoze Li
Structural Origin Of Mechanical Prowess In Conch Shells, Haoze Li
Theses and Dissertations
Conch shells are natural nanocomposites with an exquisite multiscale hierarchical architecture which exhibit coupled ultrahigh mechanical strength and toughness. What materials design strategy renders conch shells such mechanical prowess? In this study, micro/nanoscale structural and mechanical characterization of conch shells (Busycon carica) has been carried out. We demonstrate, for the first time, direct evidence that the previously claimed single-crystal third-order lamellae - the basic building blocks in conch shells are essentially assembled with aragonite nanoparticles of the size ranging from 20 to 45 nm. The third-order lamellae exhibit not only elasticity but also plasticity with the strain up to 0.7% …
Welding Parameters, Distortion And Mechanical Properties Of Aa7075 Lap Joints In Ssfsw, Hejun Yu
Welding Parameters, Distortion And Mechanical Properties Of Aa7075 Lap Joints In Ssfsw, Hejun Yu
Theses and Dissertations
Friction Stir Welding (FSW), first invented by The Welding Institute of UK (TWI) in 1991, is a solid state welding process which was initially applied to welding Aluminum Alloy. FSW has wide application in industrial sectors. Stationary shoulder friction stir welding (SSFSW) was first developed to weld low thermal conductivity Ti-based alloys, which are hard to weld using conventional friction stir welding. Previous literatures showed SSFSW can produce uniform temperature distribution through thickness during the welding process. Since SSFSW is still under study phase, its advantages and disadvantages are not yet well defined. It is important to study the characteristics …
A Comparative Study Of Strength And Stiffness Of Thin-Walled Specimens Fabricated By Fdm And 3d Printing Technologies, Miranda Rodrigo
A Comparative Study Of Strength And Stiffness Of Thin-Walled Specimens Fabricated By Fdm And 3d Printing Technologies, Miranda Rodrigo
Theses and Dissertations
Rapid Prototyped part failure constitutes a major issue for both RP providers and customers. When parts fail the reputation of the vendor is heavily deteriorated, customer dissatisfaction increase and replacement of the broken parts is often necessary to avoid the loss of future business. Product design teams often run into situations where Rapid Prototyped parts are not able to withstand shipping and handling and delivered broken or while demonstrating and examining the parts. When done in the face of customers this builds a perception of poor quality and lack of aptitude on the design group as well as the RP …
Investigate Correlations Of Microstructures, Mechanical Properties And Fsw Process Variables In Friction Stir Welded High Strength Low Alloy 65 Steel, Lingyun Wei
Theses and Dissertations
The present study focuses on developing a relationship between process variables, mechanical properties and post weld microstructure in Friction Stir Welded HSLA 65 steel. Fully consolidated welds can be produced in HSLA 65 steel by PCBN Convex-Scrolled-Shoulder-Step-Spiral (CS4) tool over a wide range of parameters. Microstructures in the nugget center (NC) are dominated by lath bainite and a few polygonal/allotriomorphic grain boundary ferrites. FSW dependent variables are related to FSW independent variables by non-linear relationship. Heat input is identified to be the best parameter index to correlate with microstructures. With increasing heat input, the volume of bainite is reduced, the …