Influence of venting on the response of scaled aircraft luggage containers subjected to internal blast loading

This paper concerns the mitigation of damage in aircraft luggage containers subjected to internal blast loading. It reports findings of experimental and computational work on the influence of venting on the blast response of scaled unit load devices. The internal geometry of the structure was based on a 1:6 scale version of the commonly used LD-3 unit load device. To simplify the problem, only the face closest to the aircraft primary structure could deform whilst the other walls were kept rigid. Small, spherical, charges of PE4 plastic explosive were detonated inside the scaled structures. The fully confined blast tests exhibited the highest permanent displacements and were the only tests to produce rupture of the target plate. Introducing venting reduced the target plate displacement significantly. Computational simulations were developed using LS-Dyna to provide additional insight into the blast loading and its interaction with the structure beyond what could be measured experimentally. Venting appeared to have no effect on the pressure peak, but it was effective at removing the late-time pressure reflections. The influence of the side venting was slightly obscured in the experiments due to boundary pulling-in effects at higher charge masses, but the simulations showed that venting from two sides was slightly more effective in reducing target plate deformation than single-sided venting. The paper demonstrates the potential benefit of using LD-3 ULDs unit load device with canvas sides (rather than solid ones) and venting lengthwise along the aircraft body to redirect the loading away from vulnerable locations.