Polyethylene pipelines are commonly used for underground water supply systems. Leaks could occur in flange joints in these pipelines. Analysis of such joints requires detailed material model to take into account time-dependent behaviors of pipe and gasket.
In this work a flange joint is simulated by using an axisymmetric model for quick results. A G-ST profile gasket with steel core is considered to seal the joint. An internal pressure of 10 bar is assumed. The goal of the analysis is to investigate the tightness of the flange joint over 100 years by taking into account the creep of pipe and gasket. This is a challenging problem as it involves multiple nonlinearities: material, geometric and contact between multiple components.
The analysis of flange joint is performed in three steps. In the first step, bolts are tightened and in the second step, a fluid pressure is applied. In the third step, fluid pressure is held constant for 100 years and viscoelastic effects are analyzed.
Note: This exercise is part of the Solving Non-linear Problems with Abaqus course.