高速列车滚动轴承支承松动与柔性的复杂耦合动力学及其非线性特性研究

With the development of Chinese high-speed railway, it is increasingly important to ensure the safe operation of the train. The rolling bearings has been key parts of the train, so the properties and states of rolling bearings will threat directly the safe and stable operation of the vehicle. This project investigates nonlinear coupled dynamics and characteristics of high-speed train rolling bearings with pedestal looseness and flexible-complex supporting. The multidimensional coupled disturbance model of rolling bearings is established based on analyses of the longitudinal excitation, vertical excitation and transverse excitation in several cases of the high-speed train which are normal running, curve negotiation, start-stop and emergency braking. The model of stiffness and damping during the process of gradual looseness change of typical pedestal (bolt connection, welding, interference fit) are deduced based on comprehension of supporting parts and the supporting relationships of rolling bearings. Coupled dynamics models of the bogie frame-suspension-rolling bearing-shaft-wheel and rail are proposed to present loosening process, wheel-rail elastic and bearing fault. Nonlinear dynamics of rolling bearings under multiple load cases are analysed by the numerical methods. The experiment system and on-the-spot test are to verify the theoretical results. It is hopeful to reveal complex nonlinear dynamics of the rolling bearings and lay foundation for online-quantitative diagnosis. And this project may provide theoretical basis for the domestication of rolling bearings and safety of high-speed train.

随着我国高速铁路的发展，运行安全问题日益突出。滚动轴承作为列车的关键零部件，其性能和状态将直接影响到车辆安全平稳运行。本项目拟开展高速列车滚动轴承支承松动与柔性的非线性耦合动力学模型及其特性研究。通过分析高速列车正常运行、曲线通过、启停及紧急制动等多种工况下滚动轴承所承受的纵向激励、垂向激励与横向激励，建立滚动轴承的多维耦合外扰激励模型；通过深入研究滚动轴承与列车各支承部件的相互支撑关系，建立典型支承（螺栓连接、焊接、过盈配合）松动渐变过程的刚度与阻尼模型；在上述工作基础上，再研究包含松动过程、轮轨弹性与轴承故障的构架侧梁-悬挂-滚动承-轴-轮轨的耦合动力学模型；采用数值方法分析滚动轴承在多种工况下的非线性动力学特性；结合模拟实验及试车验证研究的理论成果。本项目有望揭示高速列车滚动轴承的复杂非线性动力学特性，为其在线早期诊断奠定基础，为滚动轴承国产化与高速列车安全运行提供理论依据。

松动故障的存在严重影响着机械系统的正常运行，甚至导致安全事故的发生，然而，松动故障症兆通常又与不平衡、不对中等故障类似，易造成故障误判，对于耦合故障就更加难以诊断，因此，有必要对松动故障类型、松动机理、故障特征以及早期诊断进行研究。. 考虑含支承松动的转子系统在受到不平衡力作用下振动方程呈强非线性，引入增量谐波平衡法求系统振动周期解。运用Floquet理论判定周期解的稳定性，仿真分析带有支承松动故障的转子系统复杂的运动特性，验证了增量谐波平衡法求解非线性系统的有效性。. 以半车为研究对象，考虑半车车体的浮沉、侧滚振动，前转向架或者后转向架的浮沉、侧滚振动，轮对两侧轴箱的浮沉六自由度的半车模型，建立出车体-构架-悬挂-滚动轴承-轮轨耦合的动力学微分方程组。构造一个优化的四阶Runge-Kutta算法用于数值求解，研究系统的非线性动力学特性。得出结论：随着松动间隙的增大，系统运动出现分岔，振动速度、高频成分幅值都逐渐增大，但系统振动响应的低频成分取决于列车的行驶速度，不随松动间隙改变，并且发现松动间隙比行驶速度对系统动力学特性的影响比重大。. 针对高速列车车轴轴承所受多维复杂外扰激励力的情况，建立高速列车车轴-轴承过盈配合面微动损伤动力学模型，研究高速列车车轴-轴承过盈配合面微动损伤机理，揭示其演变规律。采用有限元软件建立车轴-轴承过盈配合面的接触模型，研究路线、过盈量、摩擦系数等对列车车轴-轴承过盈配合面接触应力的影响。研究表明过盈量对配合面接触应力影响较大，接触应力随着过盈量的增加而增大，且在配合面接触边缘区域产生最大应力。而摩擦系数对车轴-轴承过盈配合面的影响较小。.与此同时，针对高速列车滚动轴承内圈松动故障，研制了一种专用于检测滚动轴承内圈与轴颈过盈配合松动故障的模拟试验台。模拟高速列车在不同工况下的轴承内圈与轴颈的配合松动故障，可实现对轴承内圈转速、主轴转速、轴温、振动等试验参数的实时监测、显示和存储。