Failure of internally pressurized cylindrical tubes for strain-rate dependent materials

The load-deformation history of a thin-walled cylindrical tube under internal pressure is investigated for elastic-viscoplastoc behaviour. The shell is assumed sufficiently long, so that length changes as well as the end effects can be ignored and a plane-strain analysis can be performed. Numerical results are generated by means of a finite element routine developed for the large-strain behaviour. Failure into different non-axisymmetric modes is triggered by prescribing various initial geometric imperfections. For the strain-rate dependent material effects considered, a criterion for the onset of instability is applied and its predictability is demonstrated by means of parametric examples.