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Full-Text Articles in Mechanical Engineering
Processing Of Zrb2-Zrc-Zrxsiy Ceramic By Reactive Metal Penetration, Nischel B. Maheswaraiah
Processing Of Zrb2-Zrc-Zrxsiy Ceramic By Reactive Metal Penetration, Nischel B. Maheswaraiah
Open Access Theses & Dissertations
The processing of ZrB2-ZrC-ZrxSiy composite by reactive metal penetration was investigated as a successor to the ZrB2-SiC composites for hypersonic vehicles application, which cannot be used for extended time at temperatures greater than 1600C due to formation of SiO and CO gases. Zirconium (Zr), zirconium disilicide (ZrSi2), and boron carbide (B4C) were reacted in graphite crucibles for 60, 120, 180, and 240 minutes. Microscopy and x-ray diffraction (XRD) deduced the formation of a heterogeneous microstructure of ZrB2-ZrC-ZrxSiy precipitates surrounded by a solidified Zr-Si melt. Unreacted boron carbide was observed in samples held at 1860C for 60 minutes and 120 minutes, …
Sensitivity Analysis Of The Johnson-Cook Plasticity Model For Hypervelocity Impacts: A Hydro-Code Study, Carlos David Castellanos
Sensitivity Analysis Of The Johnson-Cook Plasticity Model For Hypervelocity Impacts: A Hydro-Code Study, Carlos David Castellanos
Open Access Theses & Dissertations
Computer simulations have been in use for decades in the modeling of hypervelocity impacts and general large deformation problems. Several computer codes have been developed to simulate this type of problems under a variety of geometric configurations and for any number of materials. These codes make use of several constitutive material models to simulate the response of the material under a variety of thermo-mechanical conditions. The Johnson-Cook constitutive model is widely used in the simulation hypervelocity impacts for the simulation of crater formation and even perforation of target structures. This thesis presents the results of a sensitivity study of this …