【作者】 吴川；

【导师】 黄醒春；

【作者基本信息】 上海交通大学 ， 固体力学， 2009， 博士

【摘要】 近年来随着我国城市轨道交通的迅速发展,城市轨道交通对减振降噪的要求不断提高,各种减振降噪型轨道结构也得到了广泛应用,浮置板轨道作为目前最为有效的减振轨道结构形式,其工程应用实例也越来越多。本文对浮置板下橡胶减振支座的时效特性(尤其是疲劳老化特性)进行了深入研究,以加速疲劳老化试验为基础,得到了橡胶减振支座的等效刚度、阻尼损耗因子以及等效阻尼系数与试验时间的变化关系;进而编制了车辆-结构耦合动力分析程序,得到了在考虑橡胶支座疲劳老化特性的基础上,车辆-结构耦合动力系统各部分的动力特性随时间的迁移变化特性;运用基于四端参数的导纳形式功率流法,从能量的角度对浮置板轨道结构的传递特性进行研究,同时也在考虑橡胶支座疲劳老化特性的基础上,得到了浮置板轨道结构能量传递特性随时间的迁移变化特性;最后运用功率流法与传递函数法对浮置板轨道结构的传递特性做了对比研究,得到了比较一致的结论。本文主要从以下几方面进行了比较有创新性的研究:一.以浮置板橡胶支座加速疲劳老化试验为手段,得到橡胶支座的物理力学特性(等效刚度、损耗因子及等效阻尼系数)与老化试验时间的关系;将老化试验时间折算成正常工况下的服役年限,便得到橡胶支座的等效刚度、损耗因子及等效阻尼系数与服役年限的变化关系。本文的橡胶支座疲劳老化试验与一般的疲劳试验有两点不同:(1)一般的疲劳试验为等幅疲劳,而本文疲劳试验所用荷载为随机荷载,通过等效损伤疲劳编辑,简化为八级变幅载荷程序块谱。(2)一般的橡胶疲劳试验为校验性试验,即当荷载循环进行到一定次数的时候(通常为107次),终止试验并对橡胶支座的性能进行校验,如未出现破坏,则试件疲劳性能合格。但是本疲劳试验在疲劳试验进行的过程中,通过MTS疲劳试验机数据采集系统,定期采集荷载和变形信息,可以得到试件的疲劳性能在整个试验进程中的变化趋势。二.编制了车辆-结构耦合动力分析程序,并采用“动态单元法”对轮轨瞬时脱离问题进行求解。本文的“动态单元”并非真实的物理单元,而是为了计算方便而引入的,“动态单元”是否引入计算主要依赖于接触状态的判断,即接触状态的动态判据是时间和空间的函数。三.基于模块化的程序设计,将浮置板橡胶支座的老化特性引入车辆-结构耦合动力分析程序,进一步研究橡胶支座的老化特性(主要是等效刚度、损耗因子及等效阻尼系数)的变化对车辆-结构耦合系统动力特性的影响。四.引入基于四端参数法的导纳形式功率流理论,对浮置板轨道结构的竖向能量传递特性进行研究;同时进一步研究了橡胶支座的老化特性对浮置板轨道结构功率流传递特性的影响;最后运用传递函数法与功率流法对浮置板轨道结构的传递特性进行了对比研究。本文采用试验、理论分析与数值计算相结合的方式,对城市轨道交通浮置板轨道结构橡胶支座的疲劳老化特性进行了深入研究,且在此基础上,对车桥耦合系统各部分的动力学特性以及浮置板轨道结构的传递特性随时间的迁移变化特性进行了研究,对工程实践具有良好的参考价值。更多还原

【Abstract】 The requirement for reducing noise and vibration has grown rapidly with the development of the urban rail transit (URT), at the same time various modern railway tracks have been widely used in URT. As one of the most effective railway track types for reducing noise and vibration, the floating slab track system (FST) have more and more examples in engineering applications.The aging characteristic of the rubber bearings which were widely used underneath the floating slab was investigated in this paper. The relationship between the equivalent stiffness coefficient, loss factorand and the equivalent damping coefficient of the rubber bearings and the experiment hours was derived from the accelerated aging experiment under fatigue loads. Program based on the FORTRAN language was developed to deal with the vehicle-structures coupling problem, further research was conducted to obtain the relationship between the vehicle-structures dynamics characteristic and the experiment hours. Energy transmission characteristics of the FST was studied based on the power flow method and further research was conducted to obtain the relationship between the energy transmission characteristics and the experiment hours. At the last of this paper a comparative analysis between the power flow method and the transfer function method was conducted to investigate transmission characteristics of the FST and a similar conclusion has been obtained.Following questions were investigated in this paper:(1) Different factors and typical strategies which were related to the aging characteristic of rubber bearings were analyzed generally, and then the fatigue loads were determined as the main factor influencing the aging characteristic of rubber bearings.(2) The relationship between the equivalent stiffness and damping ratio of the rubber bearings and the experiment hours was derived from the accelerated aging experiment under fatigue loads. The most important and difficult point in the accelerated fatigue experiment was how to obtain the accelerated fatigue loads spectrum. Usually the following steps were included in the whole process: data acquisition, rain-flow counting, zero-mean conversion, probability distribution checking, invalid range value filter and so on. Finally an eight-level load spectrum for the fatigue experiment was derived. (3) How the dynamic characteristic of whole part of vehicle-structures coupling system changed with the service life of rubber bearings which was usually in years? This question was answered by the vehicle-structure coupling dynamics program based on the aging characteristic of rubber bearings.(4) The power flow method which was based on the accelerated aging experiment results of rubber bearings was introduced to investigate the transmission characteristics of floating slab track from the standpoint of energy transmission. How the power flow transmission characteristic of FST was influenced by the aging characteristic of rubber bearings was also researched in this paper.(5) A comparative analysis between the power flow method and the transfer function method was conducted to investigate the transmission characteristics of the FST and a similar conclusion has been obtained.Based on the fatigue experiment results, theoretical analysis and numerical computation, the aging characteristic of FST rubber bearings was investigated in this paper, the dynamic characteristic of whole part of vehicle-structures coupling system and the transmission characteristics of the FST changed with the service life of rubber bearings was studied as a further research which should be useful of reference to engineering practice.更多还原