Occupants’ Injury during a Drop Test of an Advanced Composite Fuselage Section

Abstract

The emergency landing is an important design criteria in airworthiness certification. It is associated to the cabin safety and consequently to the risk of serious injury for the occupant. The loads transmitted to the passengers during a hard landing can be fatal both in terms of intensity and duration time, and the energy absorbing systems play a fundamental role to dissipate the energies unleashed during the impacts. A barrel section was studied by the Finite Element Method to simulate the drop test consequences for the fuselage section of a wide body aircraft, and a medium velocity impact was applied to design devices and substructures able to dissipate the biggest amount of kinetic energy. A validation process was obtained following three different steps: firstly, investigating the materials, layups and material characteristics changing with load’s velocity, secondly different tests were performed on the demonstrators in order to verify the installation parameter of the devices devoted to absorb the energies, and finally the experimental results were extended on the lower lobe of the sub-cargo compartment tested at low velocity impact. These experimental results and the correlation with the numerical models allowed to extend the results on the barrel section and to evaluate the accelerations transmitted during the drop to the occupants. The satisfactory results estimated by the numerical solvers are able to aid the design and to reduce the experimental testing for the identification and the choice of different candidate solutions.