缺口敏感性对工件疲劳行为的影响

Influence of notch sensitivity on fatigue behaviour of component

为解决不同半径孔的疲劳缺口因子对工件寿命影响行为的预测和评价,在线弹性断裂力学的基础上,采用分析的方法探索疲劳缺口的影响因素,提出了一个考虑裂纹闭合的方法,讨论了裂纹闭合在非扩展裂纹形成上的影响,得到了材料晶粒尺寸较大时的小裂纹生长率低,其时的裂纹闭合能使裂纹生长终止,也得到了疲劳缺口因子与应力集中之间的关系,特别是微小孔的疲劳缺口因子随裂纹闭合减小较明显.该结果便于对工件使用寿命进行预测.

In order to solve the prediction and assessment problem of the dependence of fatigue notch factor and the effect on fatigue life for hole of different radii, this paper studied the effect factors of fatigue notch on basis of linear-elastic fracture mechanics by adopting the analytical method, proposed a method on fatigue crack closure, and studied the effect of crack closure on the formation of non-propagation crack. This study obtained the result of low rates for small cracks on large grain size, and the development of crack closure at low rates of crack growth can result in the arrest of a propagating fatigue crack. And also it drew the relation of fatigue notch factor and stress concentration. Especially it drew the result that fatigue notch factor of mini-holes rapid reduce with crack closure.