A Study of Slipper and Rail Wear Interaction at Low Speed
AIR FORCE INSTITUTE OF TECHNOLOGY WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
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The wear research presented in the work consists of results gathered from adapting a FEM based on a Holloman High Speed Test Track HHSTT mission executed in January 2008. The FEM consists of a VascoMax slipper sliding on a stationary AISI-1080 steel rail. The slipper is slid along the rail at speeds of 20 ms and 40 ms with complementary vertical velocities of -0.079 ms and -0.059 ms, respectively. The surface roughness caused by features such as asperities and valleys of the materials, is simulated in this model by five asperities, 1 micron to 5 microns on the rail and a slipper with a leading edge radius of 6 microns. The free space between the surfaces, caused by the interaction of the asperities and valleys, is approximated by three gap spacings of 0.5 microns, 1.0 micron, and 1.5 microns. This study also explores three different Mesh refinements in the wearing portion of slipper to uncover any mesh dependence affecting the amount of wear. Additional simulations were completed to highlight the effects of using more accurate material definitions, tables of specific heat capacities were used instead of static values and more applicable, lower strain rate Johnson Cook plasticity parameters were. In a final three simulations, asperities with a smooth root fillet are used to highlight the model behavioral differences due to this simple change.