Numerical Simulation of Crack Propagation in Gas Transmission Pipeline

As an important criterion of arrest control of gas pipeline, drive force of a crack must be smaller than the fracture toughness of pipe material. In this case numerical simulation of dynamic propagation of a crack is vital. A finite element model about crack propagation is established. The pipe is discreted with elastic-plastic, large deformation and quadrilateral element. Gas pressure in tip of crack is simplified as an exponent decay model. Crack growth is simulated by node force release method, in which node constrain is set free in turn according crack propagation speed. Crack drive force is expressed by such fracture parameters as energy release rate and crack tip opening angle (CTOA). An illustrative example is given. Variation of crack drive force with pressure in pipe is analyzed. The model presented can be as an analytical tool for arrest design of gas pipeline.