2020 Volume 76 Issue 2 Pages I_399-I_410
Fatigue damage process is generally divided into two stages, fatigue crack initiation and propagation. Stress intensity factor or J-integral are usually used for driving force of fatigue crack propagation. The authors have recently proposed a fatigue crack propagation life assessment method based on elasto-plasticity response at a crack tip. Firstly, fatigue crack initiation life is assessed based on elasto-plasticity FEM and Δε-Nc criterion. Fatigue crack growth rate is calculated by da/dN = Δa/Nc, where Δa is a parameter that is introduced in the method and defines the fatigue crack growth rate. Although the previous study about 2D problem has shown the high applicability, the study has not focused on the surface crack problem or the effect of mean stress on fatigue crack propagation and threshold SIF. The purpose of the present study is to evaluate the fatigue crack propagation life against surface crack existing in the stress concentration field. Comparing with the experimental result, it was verified to evaluate accurately the fatigue crack propagation life in the depth and width direction of surface crack.
