Response of pre-pressurized reinforced plates under blast loading

The effects of pre-pressurization on blast-loaded reinforced rectangular aluminum plates were studied experimentally. Rectangular clamped plates with rivet-attached stiffeners were used as a basic model of the fuselage skin of a commercial aircraft. Both non-pressurized and pre-pressurized plates (static pressure of 41.4 kPa) were considered to simulate the typical in-flight loads experienced by a commercial aircraft due to cabin pressurization. This work extends previous research on blast loading of pre-pressurized plates [Veldman RL, Ari-Gur J, Clum C, DeYoung A, Folkert J. Effects of pre-pressurization on blast response of clamped aluminum plates. Int J Impact Eng 2006;32(10):1678–95] to incorporate the effects of riveted stiffeners. An experimental system was designed using a vacuum vessel to apply a pressure differential to the reinforced test plate. Bare spherical explosive charges of C4 were then detonated at fixed distances from the plate. The permanent plate deformations or the amount of tearing in the plates were measured for 17 explosive tests with two different blast load intensities. A high-speed camera was used to determine the mechanism and time scale of failure propagation in the reinforced panels. A comparison of permanent plate deformations and damage showed two distinct results. For the least intense blast load case, both the non-pressurized and pressurized panels deformed but did not tear. In this scenario, very little effect of pre-pressurization on final panel deformation was noted. For the more intense blast load case, a significant increase in panel damage (plate tearing) was observed as static pre-pressurization increased from 0.0 to 41.4 kPa.