Numerical study on groove formation of rails for various materials

Recovered rails exhibit groove formation along the outer edge of the armature/rail contact surface in many experiments. Different causes are hypothesized, such as local melting resulting from the concentration of current density, material yielding due to high contact pressure, and material softening at elevated temperatures. Numerical simulations using the hybrid finite element/boundary element code EMAP3D were conducted to identify the cause of this damage. Various rail materials such as chrome copper, 7055 aluminum alloy, beryllium copper, and dispersion-strengthened copper are investigated. The results are presented in this paper, and they do show that groove formation is due to the effect of both material softening at high local temperature and material yielding.