橡胶弹性减振元件疲劳裂纹扩展寿命分析

Analysis of Fatigue Crack Growth Life for Rubber Vibration Damper

对NR68橡胶纯剪切试样进行疲劳裂纹扩展试验,结果表明裂纹扩展率与撕裂能之间存在幂率关系。基于疲劳累计损伤理论,以撕裂能范围为损伤参量,建立橡胶疲劳寿命预测模型。对NR68橡胶裂纹扩展试验数据进行回归分析,拟合得出模型参数。综合应用有限元结构分析方法、橡胶材料等效应力计算方法和橡胶单侧切口拉伸(Single edge notched tensile,SENT)试样拉伸试验的应力应变数据,提出橡胶弹性减振元件撕裂能范围的计算方法,从而将弹性减振元件在复杂应力状态下的疲劳寿命问题转化为单向应力状态下橡胶材料的疲劳寿命问题。利用所建模型对锥形橡胶弹簧的疲劳寿命进行分析预测,并通过锥形橡胶弹簧台架疲劳试验进行验证,结果显示预测疲劳寿命是试验疲劳寿命的1.33倍,预测精度比较理想。

The fatigue crack growth tests for pure shear specimens of NR68 rubber are carried out and the results show that a power relationship exists between crack growth rate and tearing energy.Based on the theory of cumulative fatigue damage,a fatigue life prediction model for rubber with the tearing energy range as damage parameter is built.Model parameters are obtained from fitting fatigue crack growth test data of NR68 rubber by regression analysis.The method of calculating tearing energy of elastic damping components is put forward by using finite element structural analysis,equivalent stress calculation of rubber materials and stress-strain data of single edge notched tensile（SENT） specimens in tensile tests,and fatigue of elastic damping components in complex stress state can be changed into fatigue of rubber material in uniaxial stress state.The fatigue life of a cone-shaped rubber spring is analyzed by using the model and verified by fatigue bench test result of the rubber spring.The result shows that the predicted fatigue life is 1.33 times that of the fatigue test life.So,the prediction accuracy is good.