DefinePK

Abstract

Dent, which is one of the important factors affecting pipeline
fatigue life, substantially reduces the fatigue life of the pipeline in service.
Meanwhile, the dent displacement will be changed with the operation pressure
fluctuations of the in-service pipeline, resulting in a circular bending stress,
which directly affect the pipeline fatigue life. Finite element models of typical
lateral and axial dent were established under different circumstances. On the
basis of considerable calculations, the results were subjected to univariate
and multivariate analyses, yielding the dependences of displacement on different
parameters. The calculation results were fitted by non-linear regression. The
relationships between the maximum displacement of two kinds of typical dented
pipeline and the dent depth, diameter and thickness of pipeline and the dent
longitudinal length were acquired by establishing mathematical models. And the
characteristics of the displacement variation and mathematical model of typical
lateral and axial dent were obtained.