Effects of decarburized Layer's material property on the rail corrugation development

Abstract

A rail corrugation development calculation model that can consider the non-uniformity of material properties near rail surface was established to study the effects of rail decarburized layer on the corrugation growth. Firstly, the elastic modulus and hardness at different vertical positions in the rail decarburized layer were measured using nano-indentation technique. Then a two-dimensional wheel-rail rolling contact theory model that can consider the non-uniformity of material properties was established based on elasticity theory and hierarchical model. A numerical table for fast calculation of wheel-rail contact was established. Finally, the rail corrugation development with the presence of rail decarburized layer was simulated by considering wheel-rail contact with non-uniform material properties in the vehicle-track dynamic simulation. The results show that the decrease of elastic modulus and hardness of rail decarburized layer material would accelerate the development of corrugation. The corrugation growth rate with the presence of rail decarburized layer increases 43%. The maximum peak-to-valley depth of rail corrugation is about 9 times larger on the rail with decarburized layer than that on the rail without decarburized layer. Although the hardness plays a much more significant role in the corrugation development than the elastic modulus, the elastic modulus still has some influence on the growth rate of corrugation depth. The maximum depth of corrugation considering the non-uniformity of both elastic modulus and hardness is 11.7% larger than that considering only the non-uniformity of hardness.