Experimental and numerical studies of dynamic axial compression of thin walled spherical shells

Axial compression experiments on aluminium spherical shells of radius to mean thickness ratio (R/t) values between 13 and 85 were conducted on a gravity drop hammer setup. Typical histories of their deformation, variation of shell thickness along the meridian, load–compression curves, energy absorbing capacity and mean collapse loads obtained from the experiments are presented. Influence of the R/t values of the shell on their modes of collapse and energy absorption capacities are discussed. The shells are numerically simulated and analysed in detail by using the finite element code FORGE2. The material was modelled as rigid-viscoplastic. The experimental and computed results are compared. Typical contours of equivalent strain, equivalent strain rate, different stress components and velocity distribution are presented. The dynamic response of the shells is compared with their static response.