残余应力对金属疲劳强度的影响

残余应力对光滑试样高周疲劳极限的影响可以用Goodman关系来描述，但必须要得到残余应力作用系数m、合理地提取残余应力的表征值和区分开其它因素的影响。残余应力对缺口疲劳极限的作用大于对光滑试样的作用，是由于残余应力也存在应力集中现象，而且不易衰减。残余应力的应力集中系数不仅与缺口几何因素有关，还与材料特性有关。试验研究还表明，表层残余压应力对于承受轴向载荷且疲劳残纹萌生于表面的零件也十分有益。

THE EFFECTS OF RESIDUAL STRESSES ON THE FATIGUE STRENGTH OF METAL

The effects of residual stresses on high cycle fatigue limit of smooth specimens could be evaluated by using Goodman relation with residual stress action coefficient m , but it is necessary to indicate the rational characteristic value of residual stresses and to eliminate the influence of other factors. The effects of residual stresses on fatigue limit of notched specimen are more pronounced than those on smooth specimens, because they also have stress concentration in the notched parts and are difficult to relax .However, residual stress concentration factor depends not only on the geometry of the notch, but also on the property of the material. In addition, the compressive residual stresses are profitable for the parts under axis loading, if the fatigue crack initiate at their surface.