The dynamic wheel-rail responses during the rolling contact process for high-speed trains were investigated using the explicit finite element code LS-DYNA 971. The influence of train speed on the wheel-rail contact forces (including the vertical, longitudinal, and lateral forces), von Mises equivalent stress, equivalent plastic strain, vertical acceleration of the axle, and the lateral displacement of the initial contact point on the tread, were examined and discussed. Simulation results show that the lateral and longitudinal wheel-rail contact forces are very smaller than the corresponding vertical contact forces, and they seem to be insensitive to train speed. The peak value of dynamic vertical wheel-rail contact force is approximately 2.66 times larger than the average quasi-static value. The elliptical wheel-rail contact patches have multiple stress extreme points due to the plastic deformation of the wheel tread and top surface of the rail. The vertical acceleration value of the axle in the steady condition is around 6 5 m/s 2 for the perfected wheel-rail system with the running speed below 300 km/h.

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The dynamic effects, mainly including the inertia effect and strain-rate effect, on the dynamic wheel–rail contact behavior become more and more serious as the train speed increases. The inertia effect can be automatically taken into account in explicit finite element analysis codes, while the strain-rate effect needs to be considered via inputting the related material parameters. In the present paper, the influence of strain rate on the dynamic wheel–rail contact response for the straight track case was explored, based on a 3D wheel–rail rolling contact finite element model, via LS-DYNA/explicit algorithm. Effects of the axle load and train speed on typical dynamic wheel–rail responses were discussed, and the results indicate that the coupled train speed with strain rate has a non-negligible influence on dynamic contact responses. The strain rate hardening effect increases the maximum contact pressure and stress, and inhibits the plastic deformation of the wheel–rail system. A rate-sensitive factor (RSF) was then introduced to describe the strain rate hardening effect, confirming that the rail is more sensitive to strain rate compared to the wheel. Finally, an error analysis of the wheel–rail Hertz contact theory was conducted, which further verify the differences between elastic and elastic-plastic contact solutions.

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