<p style="text-align: justify">Dent is one of the most common defects in pipelines, which can cause local stress and strain concentration in the pipeline. Dents also create a reduction of the local pipe diameter. Dent threatens the safe operation of the pipeline and it is important to study the dented pipelines. In actual engineering, increasing the internal pressure of pipeline can make the dent re-rounding and reduce the dent depth. In this paper, the process of re-rounding of the dented pipeline were investigated by numerical study. The non-linear finite element model of dented pipeline was established. The stress and strain variations in the process of re-rounding were analyzed in detail. The effect of various factors (dent depth, diameter-to-wall-thickness ratio and initial internal pressure) on the re-rounding coefficient were analyzed. The results show that the elastic recovery occurs in the re-rounding process of dented pipe. And no secondary plastic damage occurred in the dented pipeline during the re-rounding process. The coefficient of re-rounding increases with the increase of the dent depth and initial internal pressure; while the diameter-to-wall-thickness ratio displays a negative effect. Based on the finite element results, the engineering calculation equation of the re-rounding coefficient was fitted by the nonlinear regression method．</p>

Numerical Study on the Re-Rounding Process of Dented Pipelines

Paper Proceedings: https://asmedigitalcollection.asme.org/PVP/PVP2021/volume/85314

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