Mechanical Engineering Commons^™

Numerical Modeling Of Solidification Process And Prediction Of Mechanical Properties In Magnesium Alloys, Mehdi Farrokhnejad

Electronic Thesis and Dissertation Repository

A formulation used to simulate the solidification process of magnesium alloys is developed based upon the volume averaged finite volume method on unstructured collocated grids. To derive equations, a non-zero volume fraction gradient has been considered and resulting additional terms are well reasoned. For discretization the most modern approximations for gradient and hessians are used and novelties outlined. Structure-properties correlations are incorporated into the in-house code and the proposed formulation is tested for a wedge-shaped magnesium alloy casting. While the results of this study show a good agreement with the experimental data, it was concluded that a better understanding of …

Micro-Mechanical Assessment Of The Local Plastic Strain Invoked During A Splined Mandrel Flow Forming Operation, Meysam Haghshenas

Electronic Thesis and Dissertation Repository

Splined Mandrel Flow Forming (SMFF) is a metal spinning operation that involves the application of high multiaxial compressive stress states to invoke large plastic flow in the work piece. This allows for essentially one-step fabrication of complex internally-splined shapes. In this research project, the equivalent plastic strain, invoked throughout bcc (1020 steel) and fcc (5052 and 6061 aluminum alloys, pure copper, and 70/30 brass) samples, that were made by SMFF, was measured. The objective of the research were to measure the to obtain data on the effect of microstructure and mechanical parameters on the flow formability of ductile bcc and …

Process-Structure Relationships Of Magnesium Alloys, Arindam Banerjee

Electronic Thesis and Dissertation Repository

This research study characterizes the effects of solidification conditions on the resulting microstructure of an AM60B magnesium alloy during the solidification cycle of the casting. Seventeen control points are chosen from different sections of an instrument panel beam casting and its centerline coordinates are located. These control points locations are then used by Meridian Lightweight Technology Inc. to run a simulation in a MAGMASoft casting software to obtain temperature-time specific data.

An exact analytical solution to the Stefan problem is used to compute the one dimensional heat transfer for a section of the casting and to calculate its temperature distribution …

Investigation Of The Use Of Micro-Mechanical Testing To Analyze The Mechanical Anisotropy Of The Zr-2.5%Nb Pressure Tube Alloy, Richard O. Oviasuyi

Electronic Thesis and Dissertation Repository

Maintaining a safe operation of nuclear power plants is the primary requirement of nuclear power generating organizations worldwide. This necessitates the use of highly effective methods for assessing the mechanical properties of reactor materials and components. This is important since all components located in a nuclear reactor core experience high levels of neutron irradiation which cause defects to be formed in the metals’ crystal structure. The density of these crystal defects increases with increasing exposure to neutrons and cause the crystalline metal to become harder and simultaneously more brittle. This change in mechanical properties is potentially detrimental to the safe …