Theoretical, experimental and numerical investigation on the behaviour of tubular shells under internal blast loading

Explosive loading of closed cylindrical structures is one of the most complicated types of high rate loadings that can be applied on fully closed structure. Considering the complexities and unknown factors that affect the dynamic-plastic behaviour of a fully closed tubular shell under internal blast loading, the main objective of this article is to achieve a better understanding of the deformation of such a structure through different theoretical, empirical and also numerical approaches. Based on some simplifying assumptions, a new pressure–time profile for the internal explosive loading of cylindrical shells whose length is shorter than its diameter would be introduced in this manuscript. Afterwards, the fundamental equations of motion would be solved by the use of the aforementioned profile so that a practical formula for the calculation of maximum radial deformation of shell would be obtained. Comparison between the theoretical values and the results of the experimental tests conducted on several pieces of aluminium shells shows that the accuracy of the new theory is approximately 82%. Furthermore, this problem will be also modelled by the use of LS-DYNA module. Considering three separate meshing zones on the explosive charge, conveying medium and also the shell body which were connected to each other on overlapping surfaces, the numerical results for the maximum transverse displacement of the shell would be obtained from the software. Comparison between the finite element method and experimental results shows an average error of around 24%.