Effect of Interference on Stress and Strain Distribution on the Spherical Sealing Cup of a PIG in Dented Pipeline

Abstract

Abstract Regular pigging operation of the pipeline inspection gauges (PIGs) is crucial for pipeline transportation. However, the PIG is often stuck when it runs in the oil and gas pipeline due to the interaction between spherical sealing cup and dent inside the pipe. The stress and strain distribution of the outer edge of the spherical sealing cup can provide a reference to the problem of understanding the blockage. In this study, numerical simulation of a PIG with spherical sealing cups runs through a pipe with dented wall is presented using MSC Marc 2016. Effects of the interference (δ) of the spherical sealing cup on the stress and strain distribution on the outer edge of the cup were discussed based on the model. Simulation results indicate that the smaller the thickness of the spherical sealing cup, the greater the effect of the interference of the cup on the stress. And the thickness of the cup should not be too small, an example of the failure of pigging due to the small thickness of the cup and the increase in the interference is given. The conclusions obtained in this study can contribute to the optimization design of the PIGs.