Assessment of collapse resistance of UOE pipes – comparison of FE simultion of full-scale and ring collapse tests

This paper summarizes investigations on the prediction of collapse resistance of UOE pipes based upon full-scale collapse tests and ring collapse tests. The main difference between full-scale collapse tests and ring collapse tests is the length of the pipe joint, which can influence the collapse pressure due to test pipe behavior and the used testing device. The influence of the pipe joint geometry (ring length) on the collapse behaviour was analyzed in a parameter study making use of a 3D Finite Element (FE) model of both the ring collapse test configuration and the full-scale collapse test configuration. The numerical analysis showed that every deviation from ‘perfect’ geometrical and mechanical pipe properties may lead to significant reductions of collapse pressure. Therefore, in this study, actual geometrical and mechanical pipe properties were applied as initial properties in the FE model. First experimental and numerical results demonstrated that due to the different boundary and continuum conditions the collapse pressure of a whole piece of pipe and the collapse pressure of a rather narrow pipe ring might be different.