2021 年 77 巻 2 号 p. I_145-I_153
The purpose of this study is to investigate the effect of notches on fatigue strength of middle (i.e., SM490) and high (i.e., HT780) strength steels. The study is based on finite element analyses on two types of notched specimens referring to an experimental work found in the literature. A novel approach is proposed to characterize the fatigue performance of the samples based on elasto-plastic analyses carried out with an unconventional plasticity model, the Fatigue SS model, proposed by the authors. The fatigue life, expressed as the sum of crack initiation life and crack propagation life, was predicted under unidirectional cyclic loading conditions (R = 0). The main advantages of the novel methodology consist in considering the effect of irreversible deformations and the effect of the local geometry on the initiation and propagation of the crack. The numerical results were validated against experimental data proving the reliability of the new assessment method.
