THERMO-MECHANICAL COUPLING ANALYSIS OF RAIL IN ROLLING-SLIDING CONTACT

A thermo-mechanical coupling analysis of the rail under a rolling-sliding state is conducted by the thermo-elasto-plastic finite element method. The temperature rise and the stress/strain near the wheel-rail contact patch of the rail are calculated. The effect of the wheel-rail creepage is also investigated. The temperature-dependent material properties are taken into consideration in the finite element model. The movement of boundary conditions of the rail surface is used to simulate the movement of wheels. The results indicate that the thermally affected zone exists mainly in a very thin layer of the material near the rail contact surface. Both the temperature rise and thermal strain increase with increasing the creepage. The circumferential and axial residual stresses generated by the thermal load in the surface layer of the rail appear to be tensile. The thermal load caused by small creepages can reduce the residual compressive stresses generated by the mechanical load. When the creepage becomes larger, however, the thermal response has a significant influence on the residual stresses and residual strains. As the creepage reaches a certain value, the circumferential and axial residual stresses in the thermo-mechanical case become tensile stresses, while in the mechanical case they appear to be compressive stresses. With further increasing the creepage, the residual stresses and residual strains in the thermo-mechanical case increase as well.