微动疲劳寿命的估算方法研究

The Research on Calculating Method of Fretting Fatigue Life

着重分析了零构件由于微动磨损而造成的疲劳失效机制 ,说明了在这种微动疲劳模式下疲劳寿命的组成情况 ,用门槛值应力公式估算了当磨蚀坑根部萌生扩展性裂纹时蚀坑的临界深度尺寸 ,并分析了微动裂纹尖端的应力强度因子 ,得出了计算微动裂纹萌生尺寸的表达式 ,最后用上述方法计算了螺纹联接件的微动磨损寿命与裂纹萌生尺寸 ,用局部应力应变法计算了微动裂纹的萌生寿命 ,所得到的估测寿命与试验值相符 ,由此可见 ,该微动疲劳寿命的估测方法是合理的。

Based on analysis of the mechanism about component fatigue failure caused by fretting wear, it explains the fatigue constituent part under this mode. Threshold stress formula is applied to estimate the critical deep size of wear notch, beyond this size propagating crack will appear in the bottom of notch. It also analyzes stress intensity factor at the top of fretting crack, obtains the expression to calculate fretting crack geminating size. It gives the calculation on the fretting crack initiation size of bolted joint, and the initiation life of fretting crack with local stress-strained method. The result shows that the method can estimate fretting fatigue life.