Temperature Alternation Stress Analysis of Tee Pipe Weld Structure Based on Submodel Method

Abstract

In pipeline design, the position of the pipe connection is one of the weakest links because the wall of the pipe is weakened by opening and the continuity of the original structure is destroyed. Besides, the forces and torques applied by pipes through nozzles can produce high stresses in local areas of nozzles. This paper is based on transient thermo-mechanical theory, submodel method is adopted to establish the tee weld structure model. The stress distribution in key weld positions of tee pipe under temperature alternating load is analyzed. At the same time, the stress in the local discontinuous area where the stress changes rapidly at the connection between the nozzle and the shell is analyzed accurately. Finally, the strength of the weld is evaluated. The results show that the maximum stress is concentrated at the weld seam, the maximum stress is 226.03 MPa, and the maximum stress gradually spreads around the branch pipe. The maximum stress calculated by the submodel method is 238.65 MP. The stress linearization of the maximum stress concentration position of the weld was evaluated. The conclusion has an important guiding role in reducing the operation failure risk, structural stress failure risk, and production medium leakage risk of tee pipes under complex temperature alternating conditions.