AUTHOR=Yingchao Fang , Dongliang Yu , Binbin Wang , Jian Xu , Heng Xuan , Hao Hou , lin Wang 

TITLE=Stress Analysis of the Effect of Additional Load on the Butt Weld of Suspended Pipeline With Variable Wall Thickness

JOURNAL=Frontiers in Energy Research

VOLUME=Volume 9 - 2021

YEAR=2022

URL=https://www.frontiersin.org/journals/energy-research/articles/10.3389/fenrg.2021.792508

DOI=10.3389/fenrg.2021.792508

ISSN=2296-598X

ABSTRACT=Under the special geological environment of the buried pipe, the ground is lost at the bottom of the pipe, which is created by various kinds of external factors. The pipe in the suspended state would be greatly deformed due to its own weight, internal pressure and other factors, resulting in failure of the pipeline. When a variable wall thickness weld occurs in the suspended section of the pipeline, the change of the pipeline stress will be more complicated and changeable. In this paper, ABAQUS software is used to establish a pipe-soil model of variable wall thickness butt welds of suspended pipelines. The internal pressure, wall thickness ratio, suspended length, weld position and cone length are analyzed. Obtaining the axial stress distribution of the pipe under different effect factors, as well as the curvature change and Mises stress change of the entire pipe along the axial direction. The results show that the stress at the root of the weld changes significantly, which has a greater impact on the stress of the entire pipeline. The change of internal pressure has little effect on the stress at the pipe weld. As the suspended length increases, the stress change at the weld is more obvious. The closer the welding seam is to the soil, the support of the soil will gradually shift the maximum stress position of the pipe from the top of the pipe to the bottom of the pipe. The longer the length of the cone will reduce the sudden change of the pipe section, which can effectively reduce the stress change. The places where the curvature changes greatly in the direction of the entire axis are at the pipe-soil separation and the middle of the pipeline, while the stress reaches the maximum at the pipe-soil separation, and the place with the largest stress change is the weld in the middle of the pipeline.