中文摘要：

采用热弹塑性有限元法和裂纹尖端位移法,对轮轨全滑接触状态下的钢轨表面斜裂纹的扩展特性进行分析。热力耦合有限元模型中,考虑轮轨自由表面与环境热对流、裂纹表面间热传导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,计算轮轨摩擦因数、裂纹表面间的摩擦因数和裂纹角度对钢轨表面裂纹扩展特性的影响。计算结果表明：在热力耦合作用下,钢轨斜裂纹的剪切扩展模式占主导;裂纹尖端最大张开位移随轮轨摩擦因数和裂纹角度的增大而增大;减小轮轨摩擦因数、增大裂纹表面摩擦因数和小的裂纹角度,可限制钢轨表面斜裂纹的扩展。

英文摘要：

An oblique surface crack growth behavior in rail under wheel-rail full slip contact loading and frictional heating is analyzed by the thermo-elasto-plastic finite element method and crack tip displacement method.In the present thermo-mechanical coupling finite element model,the heat-convection between the rail and ambient,heat transfer between the crack surfaces,and temperature-dependent material properties are taken into consideration.The wheel-rail rolling contact is simulated by moving boundary conditions.The effects of the frictional coefficients of wheel-rail contact and crack surfaces and the crack angle on crack growth behavior are investigated.The results reveal that the shearing mode crack growth for the thermo-mechanical case is more likely to occur.The maximum crack tip opening displacement increases with increasing the wheel-rail friction coefficient and the crack angle.Reducing the wheel-rail contact surface frictional coefficient,avoiding the small crack-face frictional coefficient and the small angle of crack can delay the rail surface crack growth.