考虑钢轨表面粗糙度的轮轨滚滑细观模型及接触行为研究

Deepening the investigation on frictional rolling contact is of importance for the safety of railway transportation..This project is aiming at building a mesoscale model for frictional rolling contact between curved surfaces, validating the model by experiment and investigating the contact behavior of rail and wheel via numerical simulation. The research is going, firstly, to build a model considering surface roughness which can describe the dynamic properties of friction between contacting surfaces. Secondly, to simulate the dynamics of Euler’s disk rolling on a table with the mesoscale model and validate it by comparing with experiment observations using high-speed cameras based on computer vision. Finally, investigate the contact behavior of rail and wheel numerically with the built mesoscale model, studying the area and shape of contact, stress distribution in normal and tangential direction on contact area, stress distribution inside wheel and rail, plastic deformation, adhesion coefficient and so on. Validation will also be carried out by comparing simulation result with results based on Coulomb Friction Law as well as experiment results in literature..Describing rolling contact behavior precisely at meso-scale and deepening investigation on rail-wheel contact is important for improving rolling contact performance between wheel and rail and ensuring the smooth and safe operation of the trains. .

轮轨关系的深化研究对铁路列车的安全平稳运营有重要意义。.本项目建立空间曲面滚滑接触细观模型，采用数值仿真及实验验证等方法研究滚滑接触行为。本项目的主要研究内容是：首先，建立考虑接触表面粗糙度的滚滑细观模型，以更准确地刻画滚滑接触行为；然后，将该模型应用于欧拉盘滚滑动力学仿真，基于已建立的欧拉盘滚滑动力学模型及非接触测量实验开展模型的实验验证；最后，在细观模型得到实验验证的基础上，建立轮轨接触有限元模型，通过仿真研究轮轨滚滑接触接触行为，分析轮轨接触斑、接触区域法向及切向应力分布、材料内部应力分布和塑性变形等接触规律及黏着系数规律，并将仿真结果与采用库伦摩擦刻画切向作用的模型仿真结果对比分析。.在细观尺度上更精确地描述轮轨滚滑接触行为为目标，开展轮轨关系的深化研究，对改善轮轨关系、优化轮轨接触及保障铁路列车安全运营有实际意义。.

本研究提出一种崭新的细观摩擦接触模型，通过刻画轮轨真实接触的界面上粗糙峰之间连接的建立、拉伸、断开并重新建立的动态循环，使其准确刻画轮轨接触界面的动态摩擦行为。.本研究通过对实验数据和细观尺度关于表面粗糙度的研究结果的进一步调研，进一步修正所建立的模型，提升模型的表现。本研究通过仿真模型与文献中的实测数据的对比验证了模型的有效性性。相比较传统轮轨接触模型（库伦摩擦与弹性半空间假设为基础），提出的多尺度模型通过对接触区内接触点对连接的建立、拉伸、断裂、休眠和重新建立循环的动态刻画，不仅能刻画模拟出轮轨接触的纵向蠕滑作用，更可以揭示速度对轮轨滚滑接触摩擦性质的影响，揭示摩擦演变机理。该模型刻画动态摩擦性能的特点，使其对刻画对列车行驶安全关键的启动、制动过程中的轮轨滚滑接触行为具有特殊优势。