Effects of Pre-Pressurization on Plastic Deformation of Blast-Loaded Square Aluminum Plates

The effects of static pre-pressurization on the blast-induced deformation of square aluminum plates were studied both experimentally and numerically. In this study, small (0.152 x 0.152 x 0.0016 meter) clamped plates were used as a basic model of the fuselage skin of a commercial aircraft. Both un-pressurized and pre-pressurized plates (static pressure of 62.1 KPa (9.0 psi)) were considered to simulate the minimum and maximum in-flight loads experienced by a commercial aircraft due to cabin pressurization. This work extends previous research on blast loading of plates to incorporate the effects of pre-pressurization. Experimentally, a vacuum vessel system was used to apply a pressure differential to the test plate. Bare spherical explosive charges of C4 were then detonated at fixed distances from the plate. The permanent plate deformations were measured for twenty-four explosive tests that considered four different blast load cases. In addition to the experimental work, numerical predictions of the permanent plate deformations were determined using finite element analysis and the commercial software ANSYS/LS-DYNA. A comparison of plate deformations determined experimentally with those predicted with the finite element method shows good correlation. For the four explosive load cases studied, no significant change in permanent plate deformations was observed as static pre- pressurization increased from 0.0 kPa to 62.1 kPa.