Effect of Scratch on Fatigue Life of Fasten Holes

FEM was used to analyze the stress field of fasten hole with scratch under tensile loading.The depths of scratch are 50μm and 100μm.On the basis of calculation results,fatigue life was estimated by nominal stress approach.Special attentions have been paid on the influence of depth and location of scratch on fatigue life of fasten holes.The results show that ① there is an influence area,only when scratch is in this area,the fatigue life of fasten holes can be effected by scratch.The deeper the scratch is,the larger the influence area is;② when scratch is in this area,the deeper the scratch is or the closer the location of the scratch to the centre of influence area is,the shorter the fatigue life of fasten holes is.