Experimental Investigation of Large Plastic Deformation and Fracture in Explosively Loaded Open-Ended Steel Cylinders

The paper presents an experimental investigation into the internal blast loading of open-ended, seamless, mild steel cylinders. A series of 10 trials were conducted on explosively loaded vessels using increasing masses of PE4 explosive. The objective of these trials was to determine the maximum circumferential strain induced in the cylinder wall as a result of the blast loading and also to determine the minimum amount of explosive required to cause wall failure in the cylinder. A cylindrical-shaped charge was detonated at the centre of the cylinder as this was more likely to produce a symmetrical blast wave than a spherical-shaped charge. The response of the cylinder with increasing charge size goes from large plastic deformation to failure by propagation of longitudinal cracks in the region of localized wall thinning. It is thought that the localized wall thinning is a result of unstable modal vibration and this is confi rmed by instability analysis. This investigation has allowed insight into the failure process of these structures not previously examined under the given loading conditions. The data generated in these trials has been used successfully to validate numerical and theoretical models of the cylinder response to impulsive loading.