On the buckling crossover of thick-walled pipe bend under external pressure

Pipe bend is a common junction in pipeline system. In this study, the post-buckling behavior of deep-sea thick-walled pipe bend under external pressure is studied by numerical simulation. A 4-node tetrahedron solid element based on vector form intrinsic finite element method (VFIFE) is introduced to simulate the whole buckling process. First, the VFIFE models of the thick-walled pipes are built and the results of the VFIFE method, tradi-tional finite element method, and the experiments from other publications are compared to verify the proposed method. Then, collapse modes and collapse mechanism of the pipe bend when buckling propagates to the elbow under dynamic and quasi-static conditions are analyzed. Finally, the influence of different geometric parameters on the crossover pressure of the pipe bend is studied. These results can be used to support the buckling arrest design of pipe bends.