Effects of residual stresses on the uniaxial ratcheting behavior of a girth-welded stainless steel pipe

This study attempts to characterize analytically the uniaxial ratcheting behavior of a girth-welded stainless steel pipe. Finite element (FE) simulation of the girth butt welding is first carried out to obtain the weld-induced residual stresses employing sequentially coupled three-dimensional (3-D) thermo-mechanical FE analysis technique. A cyclic constitutive model capable of simulating the cyclic plastic behavior is presented in the framework of rate-independent plasticity theory. Verification of the constitutive model is achieved by simulating the uniaxial strain- and stress-controlled cyclic loading tests and comparing the predicted results with the experimental measurements. The verified constitutive model is then applied to the girth-welded steel pipe subjected to uniaxial asymmetric stress cycling to evaluate the influence of residual stresses on the ratcheting behavior. The results show that welding residual stresses are needed to be taken into account in an accurate estimation of the uniaxial ratcheting behavior of the girth-welded steel pipe.