Non-linear dynamic analysis of cantilever whipping pipes

Abstract

This paper presents the results of numerical dynamic analyses of a number of pipe whip problems based on non-linear shell theory using the DYNA3D (version 6.0) finite element code. The calculations are mainly concerned with the transient deformation of the pipes during the whipping process. The main purpose of the study is to check the efficacy of a recently published theoretical elastic-plastic, hardening-softening (e-p-h-s) model for pipe whip developed by Reid et al. [1, 2]. This model is based upon beam theory but allows for the effects of ovalization of the pipe cross-section on the moment-curvature constitutive behaviour of the pipe. It is shown that the results using DYNA3D are in good agreement with both experimental data and the e-p-h-s model predictions and confirms the accuracy of the latter. While the DYNA3D study is not exhaustive, the localized shell bending deformation of whipping pipes in which ‘kinks’ are formed is reproduced with reasonable accuracy and it has permitted the effect of the strain-rate sensitivity of the yield stress of the pipe material to be examined in a preliminary manner.