OS0822 Prediction of low cycle fatigue life of elbow by revised universal slope method

Abstract

Low-cycle fatigue tests and finite element analysis were conducted using 100A elbow pipes made of STPT410 carbon steel or SUS304 stainless steel with local wall thinning. Local wall thinning was machined on the inside of the elbows in order to simulate local wall thinning. The local wall thinning located in two different areas, called extrados and crown. The elbows were subjected to cyclic in-plane bending under displacement control with inner pressure of 9 MPa. The crack penetration and the crack direction were predicted accurately by finite element analysis in consideration of principal strain range and bi-axial stress factor. Fatigue lives could be predicted accurately by the revised universal slope method.