Displacement Analysis of Plain Dent on Pipeline Based on FE Calculation

Abstract

According to the report of the United States transportation department, mechanical damage is one of the most important reasons for the pipeline accident .The most typical form of mechanical damage is indentation. Dent defect is one of the important factors affecting pipeline fatigue life, and it will greatly reduce 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. For typical plain dent on pipeline, the finite element models are established under different circumstances. A large number of the calculation results are sorted and inducted. On this basis, the results are analyzed by univariate. Non-linear regression analysis was utilized to fit the results, some specific expressions of the relationship between the dented pipeline displacements and the wall thickness and diameter of pipeline, the dent depth and longitudinal dent length are obtained after much calculation and analog.