Mechanical Behavior and Evaluation of Dented Pipe Caused by Cylindrical Indenter

Abstract

The defect of pipe dent has a great threat to the safety of oil and gas pipe transportation. In this paper, the numerical calculation model of pipe extruded by cylindrical indenter at vertical and transverse direction was established. Effects of indenter displacement, indenter radius and internal pressure on the dent behavior were discussed. The results show that different action forms of the indenter would cause different dent behaviors. A large degree of plastic deformation is formed at the edge of the cylinder end of the indenter when indenter made a vertical action. The larger the indenter radius is, the larger the plastic deformation is. But when the indenter extrudes transversely, the change in the indenter radius has little influence. For pressure pipeline, the strain in the dent fluctuates in a certain degree, and the plastic strain is larger than that in the non-pressure pipeline, but the dent depth would be lower in the end. Under different conditions of internal pressure, the laws of dent with “non-pressure” and “loading pressure” are the same, and the dented laws of “pressure” and “unloading pressure” are consistent. The strain and the depth of the dent achieve an extreme point or maximum near the edge of the dent.