Fatigue Life Assessment of Petroleum Pipe Elbows

Abstract

Pipe elbows are important components in piping systems. When a thin-walled elbow is subjected to variable amplitude loadings (VAL) as internal repeatable or random load pressure, piping elbows are vulnerable to crack. The strain concentrated at the inner and outer surfaces of the elbow pipe for the locations at crown, intrados and extrados. The finite element analysis with the nonlinear kinematic hardening model has been used to evaluate the behavior of the piping elbows under Low Cycle Fatigue (LCF) condition for all the loading ranges considered. This analysis program included monotonic and cyclic loading systems. For this purpose, the finite elements analysis was being used for the modeling and simulation based fatigue analysis code procedure. Different elbows show the fatigue life behavior based on different locations. The simulation results showed that more studies on the piping elbows need to be perfumed in order to obtain more accurate fatigue life.