Damage and Springback Analysis of Two Typical Dented Pipelines With Different Parameters

During pipeline construction, the pipeline may be impacted by sharp rocks or excavators. To study the failure mechanism of the pipeline, the damage degree and springback rate of the pipelines with two typical dents (transverse and longitudinal) were analyzed in terms of various factors (indenter size, pipeline size and internal pressure, and dent depth). The results reveal the following: (1) when pipeline size and internal pressure are unchanged and indenter size is changed, the integral value I used to measure the damage degree of the dented pipeline increases with increasing dent depth. When the dent depth reaches a certain value, at the same dent depth, the smaller the indenter size, the larger the damage integral value; (2) when other parameters remain unchanged, the larger the pipeline size is, the larger is the damage integral value, and the larger the internal pressure is, the smaller is the damage integral value. (3) The curves for damage and springback for the two kinds of dents are basically similar. Generally, the maximum damage of the longitudinal dent is larger than that of the transverse dent. (4) By a combination of an orthogonal experimental design and a gray correlation degree calculation, for the damage integral value of the two typical dented pipelines, the order of importance of the influential factors was obtained. (5) Formulas for the damage integral value and influence factors were fit using a nonlinear regression method, which provides a reference for calculation of pipeline damage.