Simulation of Crack Propagation of a Skidded Rail Wheel Using Extended Finite Element Method (XFEM)
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Date
2016-03
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Addis Ababa University
Abstract
In this thesis work, an investigation of a crack growth pattern due to the
additional effect of the frictional heat induced on the static mechanical full load
due to skidding of a wheel on a rail is conducted using an Extended Finite
Element Method (XFEM).
The contact parameters are determined using Hertz contact theory. The
assumption of the elliptical contact pressure distribution is linearized to give a
simple rectangular pressure distribution. The contact elliptical area is also
assumed to be as an equivalent rectangular area. The frictional heating case is
considered at the maximum sliding velocity having in mind the full loading
spectrum of the wheel on the entire journey. The Material of the wheel is
assumed to be an isotropic hardened Elastic-plastic material and the damage
initiation criterion selected is the maximum principal stress. An energy based
damage evolution is selected for the crack growth simulation.
The crack Extension pattern with respect to the crack tip maximum principal
stress and Equivalent plastic strain (PEEQ) are plotted for both case scenarios
and it is can then be inferred that the as the crack length increases the crack
tip stress and plastic strain also increases therefore the wheel will lose integrity
for further successive damage.
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Keywords
rack propagation, Elastic-Plastic, Frictional Heating, Hertz contact Theory, Extended finite Element Method (XFEM), Maximum principal stress, Equivalent plastic strain (PEEQ)