Three-Dimensional Analysis of the Effect of Out-Of-Plane Constraint on the Local Plastic Strain around Crack Front

Abstract

In the last few decades, constraint effects and plastic strain ahead of crack front have played important roles in stress corrosion cracking (SCC) behaviour of reactor pressure vessels (RPV) and pipes. At the same average J-integral, the local three-dimensional stress-strain fields around crack fronts were simulated, the effects of out-of-plane constraint (specimen thickness) on plastic strain, plastic zone and SCC driving force along crack fronts were analyzed. The results show that the strains of thinner specimens near the free surface are more sensitive to out-of-plane constraint effect. The strain gradients of thinner specimens are more sensitive to out-of-plane constraint, especially near the free surface. The results may be used in incorporating out-of-plane constraint effects in structures for improving structural integrity assessments and analyses of RPVs and pipes.