UNDERWATER SHOCK RESPONSE OF A CYLINDER SUBJECTED TO A SIDE-ON EXPLOSION

The nonlinear dynamic response of a cylinder subjected to a side-on, far-field underwater explosion was studied using both numerical and experimental techniques. Both ends of the cylinder were closed with thick flat plates. An explosive charge was located 25 feet (7.62 m) from the cylinder on a line perpendicular to the cylinder axis and equidistant from the cylinder ends. Comparison of axial and hoop strains was made between the strain gage measurements and the numerical results at several different locations on the cylinder. Overall, the comparison was in a good agreement. However, it was found that there were asymmetric strain gage data from the experiment. With the postulation of cylinder rotation so that the charge was not located at center of the cylinder length, an additional numerical study was undertaken to investigate the effect of the rotation on the strain distributions. This study showed improvements of the numerical results compared to the experimental data. The numerical study indicated that the dynamic motion of the cylinder has an accordion mode, a breathing mode and a whipping mode.