基于线性疲劳累计损伤橡胶悬置疲劳寿命预测研究

橡胶元件疲劳寿命的有效预测是其设计开发过程中的重要环节。引入橡胶元件线性疲劳累计损伤原理,提出张量形式橡胶疲劳寿命公式,且根据橡胶材料的实际承载工况提出其失效标准。依据橡胶材料的承载变形可简化为单轴拉伸及简单切应变,设计用于承载拉伸载荷的哑铃型橡胶试柱和承载剪切载荷的环形橡胶试柱,并实测疲劳寿命数据,以最小二乘法原理拟合拉伸与剪切的疲劳寿命函数公式。以车用变速箱悬置与发动机后悬置为疲劳寿命预测研究对象,通过分析其承载位移载荷时的应变张量,利用张量形式的疲劳寿命预测公式预测两种悬置在两种典型工况下的疲劳寿命。结果发现,橡胶材料的拉伸疲劳寿命曲线与简单剪切疲劳寿命曲线的变化趋势一致、形状类似、拟合函数幂指数十分接近;张量形式的疲劳寿命预测公式可有效地预测橡胶悬置的疲劳寿命。

Study on Prediction of Fatigue Life of Rubber Mount Based on Linear Cumulative Fatigue Damage Theory

Effectively predicting the fatigue life of rubber components is a crucial part of design and development for them.In this study,the principle of linear cumulative fatigue damage is introduced to fatigue life prediction of rubber components.Afterwards,a standard for fatigue failure of rubber materials in actual loading conditions is recommended.Based on a simplified deformation of rubber material,dumbbell-shaped test column for tensile load and rubber ring rubber test column for bearing shear load are designed and its fatigue life data are obtained.To develop a formula of fatigue life,the least square method is employed with using tensile and shear test data.Taking one rear mount of engine and another mount of gearbox as research examples,their fatigue life are predicted and compared with experimental result in two typical operating conditions,which validated the predictive method for rubber component fatigue life in present work.The comparison also revealed that,the trend and shape of tensile fatigue life curve and simple shear fatigue life curve of rubber material are strikingly similar.Moreover,the fatigue life of the rubber mount can be effectively predicted by using fatigue life prediction formula of tensor form.