Non-linear dynamic analysis of cantilever whipping pipes

This paper presents the results of numerical dynamic analyses of a number o f pipe whip problems based on non-linear shell theory using the DYNA3D (ver sion 6.0) finite element code. The calculations are mainly concerned with t he transient deformation of the pipes during the whipping process. The main purpose of the study is to check the efficacy of a recently published theo retical 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 a llows for the effects of ovalization of the pipe cross-section on the momen t-curvature constitutive behaviour of the pipe. It is shown that the result s 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 ac curacy and it has permitted the effect of the strain-rate sensitivity of th e yield stress of the pipe material to be examined in a preliminary manner.