基于开裂能密度及裂纹扩展特性的橡胶隔振器疲劳特性预测

A method to predict fatigue performances of rubber isolator based on the cracking energy density and the fatigue crack growth characteristic of rubber material

基于开裂能密度的连续介质力学参数及橡胶材料裂纹扩展特性(裂纹扩展速率与撕裂能之关系),获得橡胶部件多轴疲劳特性计算公式,并计算某汽车动力总成橡胶隔振器的疲劳特性。计算与试验对比表明,橡胶隔振器疲劳特性预测(寿命、开裂位置及开裂方向)与实测较一致。预测疲劳寿命分布在实测疲劳寿命的1/2倍分散因子内,满足工程疲劳寿命预测要求。提出的橡胶隔振器多轴疲劳特性预测方法,可用试验效率较高、投入较少的材料裂纹扩展试验代替耗时较多的材料疲劳破坏试验,不仅能为橡胶部件前期疲劳设计提供参考,亦能大幅缩短产品疲劳设计周期。

A method for predicting rubber isolators＇ fatigue performances including fatigue life, failure location and crack orientation was proposed. The cracking energy density and the fatigue crack growth characteristic of the studied rubber material were used in the proposed method. A typical type of rubber isolator was taken as an application subject so as to validate the proposed formula. The comparisons of the calculated and the measured results （fatigue life, failure location and crack orientation） reveal an acceptable consistence between them. Especially, the predicted fatigue life falls within a scattering factor of 1/2 of the experimental life, which is acceptable in engineering. The proposed method for predicting fatigue performances, which needs fatigue crack growth experiment instead of the traditional fatigue experiment that costs a lot of rubber materials, can give a direct guideline for fatigue-proof design of rubber isolators.