Longitudinal dynamic fracture of polymer pipes

To study the rapid crack propagation (RCP) resistance of polymer pipes, an experimental set-up and a numerical model are proposed. The way to solicit polymer pipes, imposed displacements or pressure, is discussed. Indeed, it has been demonstrated that it is necessary to load polymer pipe with imposed displacements and not internal gas pressure. For a pressurised pipe, a relevant estimation of the energy released rate is difficult because of the work of external forces which can not be precisely determined during crack propagation and of course during gas leak. An experimental set-up, with imposed displacements, has been machined to ensure an approximately L = 13R permanent RCP regime with L and R which are, respectively, the length and the radius of the pipe. The energy release rate is then calculated with the help of a finite element procedure knowing the crack tip location.