车轮滑动时钢轨热弹塑性有限元分析

Thermo-elasto-plastic Finite Element Analysis of Rail during Wheel Sliding

利用有限元分析软件ABAQUS建立轮轨接触热弹塑性平面应变热机耦合有限元模型。模型中,材料本构采用的是双线性塑性模型,考虑轮轨自由表面与环境的热对流的影响和温度对材料参数的影响,通过移动边界条件模拟轮轨接触区的移动。分析车轮滑动时不同摩擦因数和轴重对钢轨温度场和残余应力分布的影响。计算结果表明,钢轨表面最高接触温升发生在接触斑中心后半轴靠近边缘处,温升主要分布在接触表面大约1.6mm的深度范围,钢轨表层最大VonMises等效应力发生在离钢轨表面大约0.2mm的次表面;残余应力应变的影响主要在钢轨表面大约10mm范围内,在钢轨表面考虑热影响时残余应力比不考虑热影响的大;考虑热影响时钢轨表层的温度随摩擦因数和轴重的增大而增大,钢轨表层残余应力也随着摩擦因数的增大而增大,而轴重对钢轨表面残余应力影响不明显,而在次表层影响很大。

A thermo-mechanical coupling elastic-plastic plane strain finite element model is established by using the finite element code ABAQUS.A bilinear plasticity model is used.The heat-convection between the rail surface and ambient and temperature-dependent material properties are taken into consideration in the numerical model.The movement of boundary condition is used to simulate the movement of wheel/rail contact patch.The effects of different friction coefficients and wheel loads on the temperature fields and residual stresses in the rail are investigated in detail.The numerical results show that the maximum surface temperature rise occurs close to the edge of tail half axle of the contact patch.The temperature rise affected zone exists in the 1.6 mm depth range of rail surface.The maximum Von Mises equivalent stress occurs about 0.2 mm in the surface layer of rail.The influencing depth of the residual stresses and the residual strains is about 10 mm.The residual stress near the rail surface with thermal effect is larger than that without thermal effect.The temperature of the rail near the surface increases with increasing the friction coefficient and the axle load.The residual stresses near the rail surface increase with increasing the friction coefficient.But the effect of the axle load on the residual stresses near the rail surface is not obvious,while on the residual stresses in the subsurface layer of rail is significant.