Thermo-mechanical coupling analysis of three-dimensional full-size wheel/rail contact at different slip ratios

A rolling-sliding contact state between wheel and rail appears when a train starts, brakes or passes through long-heavy down grades. During this process, significant damage and thermo-mechanical coupling phenomena occur on contact surface. To analyze this thermo-mechanical phenomena, a detailed three-dimensional full-size wheel/rail interaction model is constructed. The results indicate the contact patch shape of wheel/rail is close to an ellipse, and contact area is 164.3 mm^2. The maximum von Mises stress of wheel and rail are 488 MPa and 494 MPa , respectively. The maximum temperature is consistently observed at the center of the contact area under varying wheel/rail rolling-sliding contact conditions. During pure sliding contact, the maximum temperatures on the wheel and rail surfaces reach 1495.8 °C and 594.3 °C respectively. The temperature variation becomes negligible when the point is located beyond 3 mm from the contact interface. The von Mises stress of node is evidently higher than that of pure rolling contact because of the thermal and mechanical load at different slip ratios, and this difference gradually increases with increasing slip ratios. When the slip ratio exceeds 0.75, the thermal strain and plastic strain of the wheel increase rapidly. The findings of this study provide significant insights into the thermo-mechanical coupling phenomena at the wheel/rail interface during train braking.