Influencing Factors for Fatigue Strength

Metal fatigue is a weakened condition induced by repeated stresses which ultimately results in cracks or even fracture and, thus, has to be understood in terms of its influencing factors. In this chapter, the fatigue strength of materials and components will be reviewed including the major parameters which have an effect on the number of cycles-to-failure. Material- and process-related effects will be discussed as well as stress concentration and surface conditions. A major proportion of this chapter is related to the effects of mean stresses and residual stresses to demonstrate effective measures for improving fatigue strength and, thus, optimizing lightweight design.