Factors Affecting the Fatigue Life of Springs

This chapter examines the effects of mean stress, multiaxial loading, and residual stresses on the fatigue life of springs. We study the fatigue life of homogeneously stressed material subjected to cyclic loading with non-zero mean stress. Traditional fatigue life estimation methods are based on Goodman and Haigh diagrams. The formal analytical descriptions, namely stress-life and strain-life approaches, are more suitable for numerical methods. The method of fatigue analysis described above, which describes the crack growth per cycle, is extended. The extensions allow for the consideration of the mean stress of the load cycle. Closed-form expressions for the crack length over the number of cycles are derived. The complementary effects on the fatigue life of springs, which ultimately significantly influence the fatigue life of springs, are succinctly pronounced. This chapter is the second section of the third part, which surveys the life cycle of elastic elements.