不平整路面上的车辆等效动载系数

采用双自由度4参数的四分之一车辆振动模型，以路面不平整度为激励，运用随机振动理论分析了不平整路面上的车辆随机动载，得到了车辆动载、车辆动载峰值及其系数的概率分布.基于车辆动载峰值的概率分布以及Palmgren-Miner线性累积疲劳损伤理论，推导了车辆对不平整混凝土路面的等效动载峰值及其系数的表达式，建立了车辆随机动载与确定性动载之间的关系，进而根据车辆随机振动确定车辆动载系数.算例分析表明，在以均值加3倍方差作为车辆可能出现的最大动载的情况下，最大动载系数和等效动载峰值系数随车速及路面不平整度的增大而增大，但在相同条件下，最大动载系数远大于等效动载峰值系数，说明采用最大动载系数进行路面结构设计是偏于保守的.

Equivalent vehicle dynamic load coefficient on rough pavement

A quarter-vehicle vibration model with two degrees of freedom and four vehicle parameters was built and pavement surface roughness(PSR) was taken as excitation in the model.Stochastic vibration theory was used to analyze the random dynamic vehicle loads on rough pavement.Then The probability distribution of dynamic vehicle load,peak dynamic load(PDL),dynamic load coefficient(DLC) and peak dynamic load coefficient(PDLC) were obtained.The expression of equivalent dynamic load(EDL) and equivalent peak dynamic load coefficient(EPDLC) of vehicle on rough concrete pavement were deduced based on the probability distribution of PDL and Palmgren-Miner linear cumulative damage theory.The relationship between random and certain vehicle dynamic loads was established.A case study indicates that,if the sum of means and three times variances of vehicle loads is taken as the maximum dynamic load coefficient(MDLC),the higher vehicle velocity and pavement roughness,the bigger the MDLC and EPDLC are,but the MDLC is far bigger than the EDL on the same condition,so it is conservative to adopt MDLC in road structure design.