The Study on Crack Dynamic Propagation in the Rich Gas Transmission Pipelines

Based on the theories of dynamic fracture mechanics and the DWTT (Drop Weight Tear Test), the whole process of crack dynamic propagation of rich gas pipeline is simulated with the finite element method. The decompression behaviour of rich gas is considered and a three-stage linear decompression mode is put forward to simulate the behaviour of rich gas phase transition in ruptured pipeline, and the pressure plateau caused by the phase transition of rich gas is calculated by a multi-parameter state equation. The dynamic parameter (the CTOA, Crock Tip Opening Angle) varied with the crack location is obtained under various conditions, such as different gas components, different initial pressure, and different SDR (Standard Dimension Ratio). Through comparison of experimental data and numerical results, the reliability of engineering is valuated in rich gas transmission pipelines.