Stress Analysis for the Tie-in Girth Weld of X90 Pipeline

Abstract

Tie-in is a very important step on the final stage of pipe construction. The stress of the tie-in girth weld is really one of the key roles that affect the security of the pipeline in service. In this paper, Finite Element Method (FEM) was used to determine the stress of the tie-in girth weld. The factors of stress of tie-in girth weld were analyzed. The results show that uncovered pipe length, tie-in offset and misalignment were the important factors which affect the stress of tie-in girth weld. The maximum Mises stress and axial stress at tie-in girth weld increased with the uncovered pipe length decreasing and the tie-in offset increasing. The stress also increased significantly with girth weld misalignment, especially for axial stress.