中文摘要：

采用弹塑性有限元法，分析了多步非稳态载荷下钢轨滚动接触应力和变形。多步载荷指的是钢轨同时受到机车和车辆车轮的反复作用或多趟列车通过钢轨。通过在钢轨表面重复移动Hertz法向压力分布和切向力分布来模拟车轮的反复滚动作用。材料循环塑性本构模型采用考虑材料棘轮效应的Jiang-Sehitoglu模型。分析结果表明：在非稳态载荷作用下，钢轨接触表面产生不均匀塑性变形而形成波状表面；多步载荷对钢轨残余应力影响不大；随着机车车轮通过次数的增加，钢轨残余剪应变、表面材料位移、波深和残余累积等效塑性应变将增大，在机车车轮通过之后，随着车辆车轮通过次数的增加，前三个量将减小，而残余累积等效塑性应变继续增大，但其增大的速率变小。随着机车和车辆车轮反复滚过钢轨，钢轨残余剪应变、表面材料位移和波深变化速率即棘轮率呈衰减性。

英文摘要：

Rolling contact stresses and deformations of rail under the multiple-step non-steady state loading are analyzed by the elastic-plastic finite element method. Multiple-step loading implies the action of continuous locomotive/car wheels or multiple passages of trains over a rail. Repeated wheel rolling and sliding are simulated by multiple translations of varying normal and tangential surface tractions across rail running surface. An advanced cyclic plasticity model proposed by Jiang and Sehitoglu that considers the material ratcheting effect is employed. A wavy rail running surface profile due to the uneven plastic deformation is formed under the application of the multiple-step non-steady state loading. Multiple-step loading has an insignificant influence on the residual stresses of rail. The residual shear strain, surface displacements, wave depth and accumulated residual equivalent plastic strain increase with increasing number of locomotive wheels rolling passages. After the passages of the locomotive wheels the increasing passage of car wheels reduces the residual shear strain, surface displacements and wave depth, and aggrandizes the residual equivalent plastic strain. However, the increasing rate