轨道随机激励下弹性约束轮对的首次穿越失效问题分析  

First-Passage Failure of Elastic Constraint Wheelset System Subject to Rail Stochastic Excitation

作　　者：刘伟渭[1,2] 姜瑞金 戴焕云[3] 曾京[3] 

机构地区：[1]西南交通大学峨眉校区机械工程系,四川峨眉614200 [2]南车长江车辆有限公司,湖北武汉430000 [3]西南交通大学牵引动力国家重点实验室,四川成都610031

出　　处：《铁道学报》2015年第4期24-29,共6页Journal of the China Railway Society

基　　金：中央高校基本科研业务费专项资金(2682014CX015EM);西南交通大学峨眉校区高层次人才科研专项支持基金(RC201315)

摘　　要：考虑轨道激扰和自身结构参数随机因素建立弹性约束轮对的随机动力学模型,利用奇异性边界理论分析系统的随机全局稳定性,得到系统发生首次穿越失效的条件,同时建立系统可靠性函数和首次穿越时间的概率密度函数所满足的后向Kolmogorov方程和广义Pontryagin方程,结合初始条件和边界条件给出首次穿越问题的提法。结果表明:系统能量在接近安全工作域边界时降低得较快,能量初值远离安全域边界可降低损坏概率密度峰值并将对应的时刻延迟;系统失稳后在某一时刻最危险,而不是我们常认为的时间越长系统越危险;随着轨道随机激励强度的增加会使系统可靠性下降加快,平均首次穿越时间提前。The stochastic dynamic model of elastically constrained wheelset system was established subject to track excitation and its structural random parameters .The conditions of the occurence of the first passage fail‐ure of the system were obtained in the wake of the analysis of the stochastic global stability of the system with the singular boundary theory .Meanwhile ,the backward Kolmogorov equation and generalized Pontryagin e‐quation satisfied by the system reliability function and probability density function of the first‐passage time were established ,in combination with the initial conditions and boundary conditions to present the problem of the first passage .The results showed that the system energy decreased faster when approaching the boundary of safety work field .The energy initial value ,when staying away from the boundary of the safety work field , reduced the peak value of damage probability density and delayed the corresponding time instant .T he system was in greatest danger after losing stability in a time instant ,rather than what we used to think that the longer the time was ,the more dangerous condition the system was in .With the increase of the intensity of the track random excitation ,the reliability of the system was reduced faster and the mean first passage time was earlier .

关 键 词：轨道随机激励 拟不可积 HAMILTON系统 BK方程 首次穿越 

分 类 号：U260.11[机械工程—车辆工程]