【作者】 杨阳；

【导师】 李芾；

【作者基本信息】 西南交通大学 ， 车辆工程， 2018， 博士

【摘要】 随着我国交通事业的快速发展,城市轨道交通凭借其快捷、舒适、运量大、污染小及占地少等优点,日益成为城市现代化建设中的重要基础设施。但轮轨系统产生的噪声与振动对铁路沿线环境造成了较大的影响,弹性车轮在轮芯与轮箍之间装有带有阻尼特性的橡胶元件,能够有效地降低轮轨噪声与振动。弹性车轮由于结构中存在如接触非线性、橡胶材料非线性等众多非线性因素,给其分析研究带来了诸多不便。鉴于此,论文以某压剪复合型弹性车轮为研究对象,围绕着弹性车轮等效刚度、动力学性能、轮轨磨耗、纵向振动及动态特性展开研究。橡胶元件是影响弹性车轮性能的关键部件。通过对压力试验机获得的橡胶元件载荷-挠度曲线与有限元分析结果的对比,得到橡胶材料本构模型参数,并利用该参数对弹性车轮的性能进行分析。根据刚度矩阵、质量矩阵求解弹性车轮的振动模态,当频率大于250 Hz时,弹性车轮的振型主要由轮芯或者轮箍的振型决定,且弹性车轮振动频率与轮芯或轮箍的振动频率基本一致;当频率小于250 Hz时弹性车轮的振型表现为橡胶材料的变形。弹性车轮等效刚度直接影响弹性车轮的动力学性能,研究了橡胶元件预压缩量、材料参数、环境温度对弹性车轮等效刚度的影响。使用金属材料双线性随动强化弹塑性模型研究弹性车轮橡胶元件对轮轨接触关系的影响,弹性车轮轮轨接触面积较刚性车轮轮轨接触面积增加了17.4%,最大接触压力降低了3.5%,轮轨最大von Mises等效应力降低了3.4%。弹性车轮能够降低转向架的整体刚度,将会对车辆动力学性能造成一定的影响。以国内自主研发的70%低地板有轨电车为研究对象,在弹性车轮传统模型的基础上提出弹性车轮6自由度复合模型。采用一种基于代理模型及遗传算法的优化方法研究弹性车轮等效刚度与转向架悬挂参数的最优匹配关系,并证明该方法在车辆动力学分析中的可行性。结果表明弹性车轮车辆的横向平稳性要优于刚性车轮,非线性临界速度相对于刚性车轮降低了6.6%。通过曲线时轮轴横向力、轮轨横向力、轮重减载率及脱轨系数弹性车轮均有不同程度的降低。弹性车轮轴向刚度及偏转刚度增加对曲线通过性能有利,等效刚度变化对车辆平稳性基本无影响。弹性车轮能够降低轮轨动作用力,从而减轻轮轨磨耗。为了定量研究弹性车轮的磨耗问题,基于Archard模型建立了弹性车轮踏面及钢轨型面的磨耗预测模型。研究线路条件、弹性车轮等效刚度对弹性车轮磨耗性能的影响。对于弹性车轮磨耗性能的分析可知,线路条件越差,弹性车轮相对于刚性车轮的减磨效果越明显。对于半径为500 m曲线外侧弹性车轮的减磨效果最佳,磨耗降低比率明显高于曲线半径为100 m和200 m的情况,这主要是由于曲线半径小,运行速度低,轮缘与钢轨始终接触振动较小造成的。运行弹性车轮的轨道最大累积磨耗量比运行刚性车轮的轨道最大累积磨耗量降低了33%。诸多学者在刚性车轮的纵向振动方面做了大量的研究,但弹性车轮纵向振动方面的问题长期未受到关注。论文根据不同工况的黏滑特性建立基于Polach理论与Fastsim理论的弹性车轮纵向振动动力学分析模型,分别研究弹性车轮在起动工况、低黏着高速运行、高速考虑黏滑曲线负斜率特性工况以及惰行工况下纵向振动的规律及影响因素。在起动工况时,弹性车轮振动比刚性车轮振动更加剧烈,且弹性车轮在黏着极限时的滑动远大于非黏着极限时。在低黏着高速运行时,由于轮轨作用力的频率和幅值增加,当增加到一定程度激起了轮芯相对于轮箍的大幅振动,使弹性车轮产生共振。高速考虑黏滑曲线负斜率特性工况下随着驱动力矩的减小车轮恢复黏着时间减少。在惰行工况下提高一系定位纵向阻尼是抑制弹性车轮纵向振动的有效合理方法。弹性车轮黏滑振动对构架的振动产生一定的影响,但弹性车轮振动对车体的振动影响不大。轮对弹性变形将会对轮轨接触点和蠕滑率造成一定的影响,建立考虑轮轨弹性接触的刚柔耦合弹性车轮及刚性车轮动力学模型,对弹性车轮的动态特性进行研究。曲线工况时弹性车轮的名义接触点的弹性横移量约为刚性车轮的两倍,纵向蠕滑率曲线外侧弹性车轮大于刚性车轮,曲线外侧弹性车轮轮轨横向力比刚性车轮降低了7.5%。通过正弦激励时,弹性车轮轮轨名义接触点弹性垂向变形为刚性车轮的数十倍,大的弹性变形能够缓和轮轨刚性冲击降低车轮振动加速度,轴箱的振动加速度降低了29%。更多还原

【Abstract】 With the rapid development of China’s transportation,urban rail transit is increasingly becoming an important infrastructure in the construction of urban modernization with its advantages of fast speed,comfort,large traffic volume,less pollution and less land occupation.But the noise and vibration produced by the wheel/rail system have a great influence on the environment along the railway.The resilient wheels,with rubber elements with damping properties installed between the wheel hub and the wheel rim,can effectively reduce the wheel/rail noise and vibration.However,due to many nonlinear factors in the structure of resilient wheels,such as contact nonlinearity,nonlinear of rubber materials and so on.,it has brought many inconveniences to its analysis and study.In view of this,this paper,taking a press-shear resilient wheel as the object of study,focuses on the equivalent stiffness,dynamic performance,wheel/rail wear,longitudinal vibration and dynamic characteristics of resilient wheels.Rubber element is an important factor affecting the performance of resilient wheels.By comparing the load-deflection curve of the rubber element obtained from the compression-testing machine with the finite element analysis results,the constitutive modal parameters of the rubber material are obtained,and the performance of the resilient wheel is analyzed by using these parameters.The vibration mode of the resilient wheel is solved based on the stiffness matrix and the mass matrix.When the frequency is greater than 250 Hz,the vibration of the resilient wheel is mainly determined by the mode of vibration of the wheel hub or rim,and the vibration frequency of the resilient wheel is basically consistent with that of the wheel hub or rim;when the frequency is less than 250 Hz,the vibration mode of the resilient wheels presents the deformation of the rubber material.The equivalent stiffness of the resilient wheels directly affects its dynamic performance,so the influence of the pre-compression of the rubber elements,the material parameters and ambient temperature on the equivalent stiffness of the resilient wheels is studied.The influence of rubber elements of the resilient wheel on the wheel/rail contact relationship is studied with the bilinear kinematic hardening elastic-plastic model of metal materials,and the wheel/rail contact area of the resilient wheel is increased by 17.4% relative to that of the rigid wheel,the maximum contact pressure reduced by 3.5% and the maximum wheel/rail von Mises equivalent stress reduced by 3.4%.The resilient wheel can reduce the overall stiffness of the bogie,and will have a certain influence on the dynamic performance of the vehicle.Taking the 70% low-floor tramcar independently developed in China as the object of study,the 6 degree of freedom compound model of the resilient wheel is put forward on the basis of the traditional model.An optimal method based on the agent model and genetic algorithm is used to study the optimal matching relationship between the equivalent stiffness of the resilient wheel and the suspension parameters of the bogie,and the feasibility of this method in vehicle dynamics analysis is proved.The results show that the lateral stability of the vehicle with resilient wheels is better than that of the rigid wheel,and the nonlinear critical speed is 6.6% lower than that of the rigid wheel.The wheel-axle lateral force,the wheel/rail lateral force,the rate of wheel load reduction and the derailment coefficient are all reduced in varying degrees for the resilient wheel.The increase of the axial stiffness and deflection stiffness of the resilient wheel is beneficial to the curve negotiation performance,and the change of the equivalent stiffness has no influence on the stability of the vehicle.The resilient wheel can reduce the wheel/rail action force,thus reducing the wheel/rail wear.In order to quantitatively study the wear problem of the resilient wheel,the wear prediction model of the resilient wheel tread and the rail profile is established based on the Archard model.The influence of the line condition and the equivalent stiffness of the resilient wheel on the wear performance of the resilient wheel is studied.The analysis of the wear performance of the resilient wheel shows that the worse the line conditions are,the more obvious the wear reduction effect of the resilient wheel is relative to the rigid wheel.The resilient wheel outside the curve with a radius of 500 m achieve the best wear reduction effect,for which the ratio of wear reduction is obviously higher than that outside the curves with a radius of 100 m and 200 m,which is mainly because the vibration is small due to the small radius of the curve and the flange always in contact with the rail at low operation speed.The maximum cumulative wear of the rail with resilient wheels running on it is 33% lower than that of the rail with rigid wheels running on it.A lot of studies have been done by scholars on the longitudinal vibration of rigid wheels,but that of the resilient wheels has not been paid much attention to for a long time.In this paper,the dynamic analysis model of the longitudinal vibration of resilient wheels based on Polach theory and Fastsim theory is established according to the stick-slip characteristics under different working conditions to study the law and influence factors of the longitudinal vibration of the resilient wheels under start-up,low viscosity and high speed operation,high speed operation considering the negative slope characteristic of the stick-slip curve and the coasting conditions respectively.Under startup,the resilient wheels vibrate more violently than rigid ones,and the resilient wheels slip more greatly at the viscosity limit than not at viscosity limit.Under low viscosity and high speed operation,the wheel hub of the resilient wheel resonates with the wheel rim when a large amplitude vibration of the wheel hub relative to the rim is caused due to the frequency and amplitude of the wheel/rail force increased to a certain extent.Under the high speed operation considering the negative slope characteristic of the stick-slip curve,the viscosity recovery time of the wheel is reduced with the decrease of the driving torque.Under coasting conditions,improving the primary positioning longitudinal damping is an effective and reasonable method to restrain the longitudinal vibration of the resilient wheel.The stick-slip vibration of the resilient wheel has a certain influence on the vibration of the frame,but the vibration of the resilient wheel has little effect on the vibration of the body.The elastic deformation of wheelsets will have some influence on the wheel/rail contact point and the creepage.A rigid-flexible coupled dynamic model of resilient and rigid wheels that takes the elastic contact of the wheel and rail into account is established to study the dynamic characteristics of resilient wheels.The elastic lateral displacement of the nominal contact point of the resilient wheel is about two times that of the rigid wheel under the curve working condition.The elastic lateral shift of the nominal contact point of the resilient wheel is about twice that of the rigid wheel in case of curve working conditions;the longitudinal creepage of the resilient wheel outside the curve is larger than that of the rigid wheel,and the wheel/ rail lateral force of the resilient wheel outside the curve is 7.5% lower than that of the rigid wheel.The elastic vertical deformation at the nominal wheel/rail contact point of the resilient wheel is several dozen times that of the rigid wheel when the sinusoidal excitation is imposed.Large elastic deformation can mitigate the wheel/rail rigid impact and reduce the vibration acceleration,and the vibration acceleration at the axle box is reduced by 29%.更多还原