The development of a fluid/structure interaction model for flawed fluid containment boundaries with applications to gas transmission and distribution piping

In most instances, dynamic fracture mechanics analyses of structural components can safely assume that the external loads are independent of the crack propagation and arrest event. However, for pressure vessels and pipelines this will not always be the case. Here the flow of the contained medium through the crack opening can play a significant role in dictating the crack driving forces. Typical of this important class of problems is rapid crack propagation along the axial direction of a gas pipeline. Accordingly, a computational model has recently been developed to effect a detailed analysis of this problem that accounts for the high degree of interaction between the escaping gas and the pipe wall movement during the propagation event. For this purpose, a three-dimensional finite difference fluid dynamics code has been linked with a shell finite element code. In this paper comparisons are made between the model predictions in steady state conditions with available full scale burst data for steel transmission pipelines to assess the veracity of the coupled analysis model. Applications to polyethylene gas distribution piping systems are then made with the validated model.