钢轨异常波磨动态演化机理的时变区间分析方法

Rail transit is one of the strategic pillars of the national economy in our country. However, abnormal rail corrugation usually deteriorates wheel/rail contact relationship, and causes serious vibration noise and components failure. Also, it directly impacts on traffic safety, operational economy and ride comfort. In general, it is very difficult to treat the abnormal rail corrugation because few efficient methods might be used to analyze its mechanism. In this project, theoretical analysis, numerical simulation and experimental verification are employed to build a simulation model combined structure and dynamics to imitate dynamical evolution process of abnormal rail corrugation, by integrating the stochastic finite element method and time-varying interval analytical method in the random vibration process together. Our work focuses on the time-varying interval analytical method of dynamical evolution process of abnormal rail corrugation. According to this new approach, the problem to describe mechanical mechanism of rail corrugation dynamical evolution process would be solved both qualitatively and quantitatively. At same time, the effect of time-varying damage accumulation of the rail corrugation process would be investigated. The systematic and in-depth analysis of the dynamical process that a kind of scratch on the tread evolves into abnormal rail corrugation is implemented. Development speed and damage degree of rail corrugation are predicted as varying in a region (accumulation effect), and corresponding system parameters varying in an interval (valid upper and lower bounds). This dynamic correlation approach considering uncertainty should match actual engineering preferably, and it is understood easily by engineers. After the completion of the project, a new method for comprehensive treatment of rail corrugation would be presented for rail transit field.

轨道交通是我国国民经济的战略性支柱之一，而钢轨异常波磨恶化轮轨接触关系，造成严重的振动噪声和部件失效，直接影响行车安全性、运营经济性和乘坐舒适性。异常波磨治理困难，关键在于缺少波磨机理分析的有效方法。本项目采用理论分析、数值仿真与实验验证，将随机有限元与随机振动过程不确定性时变区间分析方法相结合，建立钢轨异常波磨动态演化过程结构与动力学联合仿真模型；重点发展钢轨异常波磨动态演化机理的时变区间分析方法，解决当前波磨研究领域缺少科学方法既能定性也能定量描述波磨动态演化过程深刻的力学机理的难题，提出分析波磨演化时变过程损伤累积效应的新方法；系统深入分析踏面上一类蚀痕演变成异常波磨的动态过程，预测波磨发展速度和损伤程度的分析结果呈区域性变化（累积效应），而对应的输入参数呈区间性变化（有效上下界）。这类考虑了不确定性影响的动态关联方法更符合实际工程，也易于工程人员理解，为轨道波磨综合治理提供新方法。

本项目针对异常波磨的治理难题，重点发展了波磨动态演化机理的时域方法和波磨波长精准预测的频域方法。建立了车辆-轨道多体耦合动力学系统模型，较为完善地分析了直线及曲线工况下的系统动力响应，并结合相关现场试验有效验证了模型的适用性；从系统自激振动和耦合振动角度比较深入研究了直线线路上钢轨波磨的形成原因，并对直线线路上车-轨系统敏感参数进行了分析及优化，提出了一系列工程控制措施；从黏滑振动角度阐释了曲线线路上的钢轨波磨形成机理，并从界面摩擦管理层面提出了波磨控制措施；基于所发展的理论及方法，研究了不同工况下钢轨波磨的发展特性，以期为将来预测钢轨波磨及制定打磨计划提供指导。结合钢轨型面磨耗预测，分析了型面上磨耗分布范围和磨耗发展程度，预测波磨发展速度和损伤程度的分析结果呈区域性变化（累积效应）。同时，建立谐波波磨激扰模型，分析在谐波波磨激扰作用下轮轨接触蠕滑特性和谐波波磨发展特性的变化规律。将随机有限元与随机振动过程不确定性时变区间分析方法相结合,针对性地研究了非均匀分布的行车速度条件下，钢轨型面磨耗分布发展特性和钢轨纵向磨耗发展特性，对不同速度分布下钢轨波磨的发展特性建立更为全面的认识。