Energy absorption and deformation modes of thin PVC tubes internally grooved when subjected to axial plastic collapse

Theoretical and experimental investigations into the quasi-static plastic collapse of thin-walled PVC tubes containing a number of geometrical discontinuities in the form of internal axial grooves of constant depth, with the aim of providing information about its behaviour as an energy-absorbing device, are reported. An inextensional collapse mechanism for folding the shell in a non-symmetrical diamond fold mode, taking into account stationary, circumferential, inclined and travelling plastic hinges, is considered. The failure modes and the mean postbuckling load necessary to perform the operation are discussed. Predicted results based on the collapse modes encountered, when compared with those obtained experimentally were found to be in good agreement. © 1989, Institution of Mechanical Engineers. All rights reserved