考虑路面不平顺随机性的汽车过桥动力响应分析

Dynamic response analysis of vehicles crossing a bridge considering the randomness of road surface roughness

为分析考虑随机路面不平顺情况下的车辆过桥动力响应,建立了随机汽车-桥梁耦合振动模型,路面不平顺采用路面谱进行模拟转换,引入概率密度演化方法对系统的随机响应进行计算,通过2个算例进行了验证:与经典算例进行对比验证模型的可靠性;与蒙特卡洛法对比验证了概率密度演化方法计算随机车-桥系统动力响应的精度及效率。2个算例证明了该随机振动系统模型计算结果可靠,同时概率密度演化方法能够在保证精度的前提下有效提高计算效率。对不同道路不平度、不同车速情况下的车辆、桥梁随机响应进行分析,结果表明:车速对桥梁响应均值的影响不敏感,对车辆响应均值影响较大;桥梁与车辆响应标准差均随车速增大而增大。不同道路等级工况下,桥梁位移与车辆加速度概率最大值总体上都随车速增大而增大;在不同速度工况下,桥梁位移与车辆加速度概率最大值随着道路等级变差而明显增大。

In order to analyze the dynamic response of vehicles crossing a bridge considering random road surface roughness,a random vehicle-bridge coupling vibration model was established.The road surface roughness was simulated and transformed using the road irregularity power spectrum,and the probability density evolution method was introduced to solve the system’s random response.The calculation was carried out and verified by two examples:the reliability of the model was verified by comparison with the classical examples;and the precision and efficiency of dynamic responses of the stochastic vehicle-bridge system calculated by the probability density evolution method were verified by comparison with the Monte Carlo method results.The two cases show that the calculation results of the random vibration system model are reliable,and the probability density evolution method can effectively improve the calculation efficiency under the premise of ensuring accuracy.Finally,the random responses of vehicles and bridges at different speeds were analyzed.The results show that:the speed of the vehicle is not sensitive to the mean value of the bridge response,but it has a greater impact on the mean value of the vehicle response;the standard deviation of the responses of the bridge and the vehicle increases as the vehicle speed increases.Under different road grade,the probability maximums of the bridge displacement and vehicle acceleration increase with the increase of vehicle speed;under different speed condition,the probability maximums of the bridge displacement and vehicle acceleration increase with the reducing of the road grade.