高速轮轨动态接触与蠕滑界面行为研究

The wheel/rail contact of high-speed trains is one of the important scientific and engineering problems in the construction of high-speed train. Traditional wheel-rail rolling contact theories mainly focused on quasi-static contact problems, while the dynamic system theory only simplifies the contact to a Hertzian model without considering interfacial stick-slip, stress wave and other transient issues. This proposal aims to investigate the problems of high-speed wheel-rail dynamic contact, and will conduct the following tasks: 1) Develop a dynamic contact model for the wheel/rail interface and a fast solution algorithm to analyze the effects of speed, vibration and stress wave on the interfacial creep, taking a full account of the influences of speed, vibration, and stress waves; 2) Explore a wheel-rail hardness matching method based on the proposed dynamic contact theory, by considering the hardness distribution along the depth direction, and provide the theory basis for the improvement of heat treatment method; 3) Construct a wear model and calculation formula based on the stress and creep analyses. The curves of wear volume, vibration, creep ratio and load will be obtained from the theories and experiments, which will lead to the in-depth understanding of the wear mechanisms of high speed wheel/rail pairs caused by speed and vibration. It is expected that the results of this research will provide a theoretical basis for future wheel/rail design for Chinese high-speed rail ways.

高速铁路轮轨接触是高铁建设中急需解决的重要科学和工程问题之一，传统轮轨接触理论仅考虑准静态接触问题，而轮轨动力学系统理论仅将接触简化为赫兹模型，并未充分考虑界面蠕滑、应力波等问题。因此，本项目旨在针对高速轮轨动态接触问题，着重进行以下研究：1）构建轮轨动态接触力学模型和快速算法，充分考虑速度、振动和应力波，分析速度、载荷产生的振动和应力波对界面蠕滑的影响；2）基于动态接触力学的轮轨硬度设计方法，考虑轮轨材料沿深度方向的硬度分布与变化，为热处理方法的改进提供理论依据；3）基于应力和蠕滑分析建立磨损模型和计算公式，通过理论和实验得到磨损量与速度、振动、蠕变率和载荷等物理量的曲线和图表，最终揭示高速轮轨与速度和振动相关的磨损机理。通过该研究为我国高速铁路的轮轨设计提供科学理论指导。

在本基金资助下，项目团队对高速轮轨动态接触涉及的一些问题进行了深入研究，包括U71Mn钢在冲击载荷下的应变率相关内聚力模型；U71Mn钢在压剪应力状态下的动态响应和失效行为；高速列车轨道振动及吸振器减振方法；接触力学和摩擦学相关模型和算法。主要成果包括：1）针对钢轨材料U71Mn钢，建立了率相关内聚力模型并用于模拟裂纹的萌生与扩展。2）研究了U71Mn钢在压剪应力状态下的动态力学响应、断裂失效行为以及绝热剪切带分布规律；3）从轨道的结构出发，研究如何通过在轨道上增加吸振器抑制轨道的振动；4）基于神经网络的摩擦系数预测模型；5）具有位错-力耦合模型界面的两个无限大半空间问题研究；6）横观各向同性材料接触解析解和快速算法等。通过以上研究揭示钢轨材料的率相关损伤机理以及为高速列车的减振设计提供理论和实验指导。