基于实测载荷的汽车变速器壳体疲劳寿命预测方法

Fatigue Life Prediction Method of Automobile Transmission Shell Based on Measured Load

汽车变速器壳体的疲劳寿命直接影响汽车传动系的疲劳可靠性,针对目前对汽车变速器壳体的疲劳寿命关注过少,未结合实际道路行驶负载导致无法准确地预估汽车变速器壳体的疲劳寿命。运用有限元分析手段合理选取壳体应力测点,依托搭建的变速器壳体数据采集系统在某国内试验场实车采集动态载荷谱;依据频域特征分析对载荷进行数据处理,提取典型路面的特征值进行统计分析,运用雨流计数技术得到路面激励的雨流循环矩阵;之后对壳体的S-N曲线修正方法进行了深入分析与研究。在此基础上,根据Miner线性损伤累计理论,准确预测了基于实际用户路面的变速器壳体的疲劳寿命约为1.258×10^(5) km,对壳体可靠性分析及局部结构优化具有重要的工程应用价值。

The fatigue life of the automobile transmission shell directly affects the fatigue reliability of the automobile transmission system.At present,little attention is paid to the fatigue life of the automobile transmission shell,and the fatigue life of the automobile transmission shell cannot be accurately estimated without combining the actual road driving load.The finite element analysis method was used to select the shell stress measurement points reasonably,and the dynamic load spectrum was collected in a domestic test field by relying on the built transmission shell data acquisition system.According to the frequency domain characteristic analysis,data processing on the load was processed,the characteristic values of typical pavement were extracted for statistical analysis,and the rain flow counting technology was used to obtain the rain flow circulation matrix excited by the road surface.After that,the S-N curve correction method of the shell was analyzed and researched.On this basis,according to the Miner linear damage accumulation theory,the fatigue life of the transmission shell based on the actual user s road surface is accurately predicted to be about 1.258×10^(5) km.It has important engineering application value for shell reliability analysis and local structure optimization.