随机载荷加载下疲劳裂纹扩展速度的一种计算方法

Arithmetic of Fatigue Crack Growth Rate Under Random Loading

为了揭示出随机载荷加载下,疲劳裂纹扩展速度的规律,利用临界平面方法,把多轴随机载荷等效为单轴随机载荷,并进而简化为单轴多级恒幅载荷谱,然后利用恒幅疲劳裂纹扩展的速度公式,计算裂纹的总增加量,推导出随机载荷加载下疲劳裂纹扩展速度的计算公式。通过对试件的疲劳寿命预测,验证了该公式的正确性。

The rule of fatigue crack growth rate under random loading is revealed in the paper by derivation of the formula of fatigue crack growth rate under random loading.In order to achieve that,by the critical plane approach,multi-axial and random loading is equated with uni-axial one.And then it is simplified to be the multi-level load spectrum.With the formula of fixed stress amplitude fatigue crack growth rate,the incremental crack length is totaled up.By the prediction of the fatigue life of typical specimen,the rule is verified.