Author(s)

N. Rushton, G. Schleyer & R. Cheesman

Abstract

A programme of numerical, theoretical and experimental studies has been carried out at the University of Liverpool on the explosive loading of seamless steel pipes. Ten pipes of dimensions 800 mm long, 324 mm outside diameter and 9.5 mm thick were subjected to explosive loading along their mid-length using cylindrical PE4 charges detonated simultaneously from both circular faces. A range of charge sizes were used to determine the effect of the blast waves on the maximum plastic hoop strain in the pipe walls with the aim of determining the magnitude of the impulse required to initiate failure in the pipe wall. Theoretical analyses of the deformation process were investigated using equations available in the past literature as well as an attempted derivation of equations of motion used to analyse the transient deformation of the pipe where wall thinning is considered based on a constant volume assumption. A comparison of these analyses is made in this paper together with a numerical analysis of the problem using AUTODYN 2D where a von Mises material model was used to simulate the assumption of a perfectly plastic material. Further finite element simulations were conducted to model the blast process and structural response of the experimental pipes using cylindrical charges. It was found that a Johnson-Cook strength model for the simulated pipe material in the numerical solution gives good agreement with the test data as this model attempts to account for the strain rate and strain hardening effects of the steel. The objective of the study, which is sponsored by AWE plc, Aldermaston, is to ultimately determine the failure mechanism of such a pipe under very high rates of loading. Keywords: blast loading, seamless steel pipes, numerical simulations.

Keywords

blast loading, seamless steel pipes, numerical simulations.