Finite-Element Study of Methods for Triggering Pipeline Global Buckling Based on the Concept of the Perfect VAS Length

摘要

With the increase in pipeline operating depth, research on pipeline global buckling during the process of oil and gas transport is drawing considerable attention. Numerical simulation is an important method that is used to analyze pipeline buckling, which is immediately caused by the combined action of high temperature and high pressure. Two important problems must be solved before simulating submarine pipeline global buckling. Because the finite-element (FE) model length greatly affects analysis of the buckling results, finding a reasonable model length is the first problem in finite-element analysis (FEA). The second is how to trigger global buckling in the pipeline because the ideal pipeline would not buckle in FEA. Previous studies only state that geometric initial imperfection and interference force could trigger pipeline global buckling. Therefore, simulating pipeline global buckling in FEA becomes a problem. In this paper, an effective method for calculating the reasonable model length (also called the virtual anchor spacing, or VAS) has been put forward based on the limit equilibrium theory of the analytical solution method. Two different methods, i.e., imperfection and interference force, have been used to simulate pipeline global buckling. Based on the VAS model with perfect length, a series of analyses on lateral buckling triggered by geometric initial imperfection and interference force are given. The research shows that no direct relation exists between the triggering methods and that their analytical results significantly differ. (C) 2015 American Society of Civil Engineers.