不同损伤参量对橡胶隔振器疲劳寿命预测结果影响的研究

基于橡胶哑铃形试件的疲劳试验结果,分别以最大主工程应变、最大主对数应变、最大主Green-Lagrange应变、八面体切应变、应变能密度、Luo等效应力、Saintier等效应力为损伤参量建立七种橡胶疲劳寿命预测模型。应用此七种模型预测某汽车动力总成橡胶悬置的疲劳寿命,对比不同寿命模型的预测效果。研究结果表明,以最大主工程应变、最大主对数应变、最大主Green-Lagrange应变、八面体切应变、应变能密度为损伤参量建立的寿命模型预测的疲劳寿命均在实测寿命的4倍分散线之内;以Luo应力、Saintiter应力为损伤参量建立的寿命预测模型的预测寿命落在实测寿命的2倍分散线之内。因此,以Luo应力、Saintiter应力为损伤参量建立的寿命预测模型预测效果更好,Luo应力、Saintier应力更适合作为疲劳损伤参量来预测橡胶隔振器的疲劳寿命。

Study on the Effect of Different Damage Parameters on the Predicting Fatigue Life of Rubber Isolators

Based on the measured fatigue life of dumbbell cylindrical specimen, seven fatigue life prediction models using different damage parameters for predicting fatigue life of rubber isolators is presented. The damage parameters presented in this paper include the maximum principal engineering strain, maximum principal logarithmic strain, maximum principal Green-Lagrange strain, octahedral shear strain, strain energy density, Luo stress, Saintier stress. To investigate the effect of different damage parameters on the predicting fatigue life of rubber isolators, seven proposed prediction models are used to predict the fatigue life of a typical powertrain rubber mount. The fatigue life of the mount predicted by the seven models is estimated and is compared with the experimental fatigue life. The fatigue life calculated using the models with maximum principal engineering strain, maximum principal logarithmic strain, maximum principal Green-Lagrange strain, octahedral shear strain or strain energy density as the damage parameter is in agreement with the experimental fatigue life within a factor of four. The model using Luo stress or Saintier stress as damage parameter can predict the fatigue life within a factor of two, which is better than the other models. It’s concluded that the proposed model for fatigue life prediction with the Luo stress or Saintier stress can be used to estimate the fatigue life for rubber isolator.