FEA based prediction of crack growth behavior of 304LN stainless steel cracked and healthy piping elbows

In the present research work, a numerical methodology is demonstrated to predict the experimentally determined results of healthy and cracked piping elbows, subjected to fatigue loading. Five different types of elbows made of 304LN SS, have been studied in the present work. It includes healthy elbow as well as elbows having cracks at intrados, extrados, and at crown. Crack initiation life and crack propagation life of elbow components had been determined separately, using numerical techniques, and are finally compared with experimental results. The finite element models of healthy and cracked elbows were also validated with experimental results of ovalization of elbow. It is found that the variation of tri-axiality quotient (q) of compact tension (CT) specimen on the un-cracked ligament nearly matches in all the cases considered in the present investigation except in case when crack is at extrados and subjected to closing load (ECE-6).

Automated summary

A numerical methodology is demonstrated to predict the experimentally determined results of healthy and cracked piping elbows subjected to fatigue loading. The study includes five different types of elbows made of 304LN SS, including healthy elbows and elbows with cracks at different locations. Numerical techniques are used to determine crack initiation life and crack propagation life, which are then compared with experimental results. The finite element models of healthy and cracked elbows are validated with experimental results of elbow ovalization. It is found that the variation of tri-axiality quotient (q) of the un-cracked ligament nearly matches in all cases except when the crack is at the extrados and subjected to closing load (ECE-6).