基于模态叠加法的车体疲劳寿命分析

Fatigue strength analysis of carbody based on the mode

基于模态应力恢复法,以模态叠加法获得的车体各模态位移响应为输入,得到车体有限元各节点模态应力载荷历程;使用Miner线性累积疲劳损伤理论对车体进行疲劳损伤评估。通过对不同模态的叠加得到对车体疲劳寿命影响较大的模态,结果表明:车体疲劳寿命主要受车体前10阶低频模态影响较大,高频模态对车体疲劳寿命影响较小。单独分析各阶模态对车体疲劳寿命影响,车体第1阶垂弯模态对车体各部位疲劳寿命具有较深的影响。

Based on the modal displacement response the time history of modal stress of car body is determined by the method of modal stress recovery theory. Then the fatigue life of carbody is evaluated by the Miner accumulated fatigue damage theory. According to the analysis of influence of mode of vehicle on the fatigue life, the first ten modes of carbody with low frequency has the great influence on the fatigue life of car body, but the modes with high frequency has little effect on the fatigue life. Meanwhile by the analysis of influence of single mode on the fatigue life of the various parts of carbody,the first order vertical bending mode of carbody has the bigger impact on the fatigue life of carbody.