三维轮轨法向接触力学行为弹塑性理论分析

基于Hertz接触理论和双线性强化模型，建立了轮轨法向接触弹塑性理论分析模型，分析了轮轨法向接触力学响应特征，讨论了轴重对接触压力和接触变形的影响规律。同时，基于三维轮轨接触有限元模型模拟了轮轨接触力学行为，并引入理论误差系数分析了弹性模型和双线性强化模型对轮轨接触力学响应预测结果的差异性。结果表明，轮轨最大接触压力和接触变形量均随轴重的增大而增大；双线性强化模型的理论误差系数较小，采用双线性强化分析模型能较准确地预测轮轨接触弹塑性力学行为。研究结果可为轮轨系统安全服役和损伤评估提供理论和技术支持。

Elastic-plastic Theory Analysis of Three-dimensional Wheel-rail Normal Contact Mechanical Behavior

The wheel-rail interaction has always been one of the most important research topics in the field of high-speed railway. And with the development of higher speed and larger axle-load for trains, the wheel-rail system will undergo plastic deformation during long-term service, resulting in the aggravation of wheel-rail rolling contact fatigue and damage, which seriously threatens the safety, stability and comfort of train operation. In the present work, a combined theoretical analysis and numerical simulation are conducted to study the elastic-plastic mechanical behavior of wheel-rail normal contact. Firstly, based on the Hertz contact theory and the bilinear hardening model, the elastic-plastic theoretical analysis model of wheel-rail normal contact was established, the wheel-rail elastic-plastic mechanical response characteristics were obtained, and the influence of axle load on contact pressure and contact deformation was discussed. Secondly, based on the three-dimensional wheel-rail contact finite element model, the wheel-rail contact mechanical behavior was simulated, and the theoretical error coefficient in terms of contact pressure and contact deformation was introduced to investigate the difference between the elastic and bilinear hardening models on the prediction results of the wheel-rail contact mechanics response, which verifies the reliability of the elastic-plastic theoretical analysis model of wheel-rail normal contact. It is found that the wheel-rail contact pressure and contact deformation increase with the increase of axle load. The theoretical error coefficient of the bilinear hardening model with regard to wheel-rail contact pressure and contact deformation is small, and the bilinear hardening model is accurate enough to predict the elastic-plastic mechanical behavior of wheel-rail normal contact, which can be used for further in-depth insight into the wheel-rail rolling contact elastic-plastic mechanical response characteristic. The obtained results can provide theoretical basis and technical support for the safe service and damage assessment of wheel/rail system.