Stress Distribution of the Power Section Cup of Pipeline Inspection Gauges by Finite Element Method

The pipeline inspection gauges (PIGs) are often blocked in actual operation. As the PIG ran in the straight pipeline, elbow, and anomaly, the large deformation and stress state of the power section cup were analyzed by a three-dimensional (3D) finite element (FE) simulation to provide a basis for solving the blockage problems. A rubber cylinder model was first established to simulate the interference fit to the pipeline. Numerical and analytical results were compared to verify the accuracy of the numerical method. Based on this method, the power section model with four cups was established and the contact-pair algorithm was adopted in order to simulate PIGs running in different locations of the pipeline. The radial stress and strain were subsequently obtained. Results show that when the PIG runs in a straight pipeline the radial stress of the outer edge of the cup is evenly distributed, and when the PIG runs in the elbow and anomaly the radial stress of the outer edge of the cup indicates a cardioid distribution. (C) 2017 American Society of Civil Engineers.