Mitigation of Impact Damage with Self-Healing and Anti-Sloshing Materials in Aerospace Fuel Tanks

In this study, self-healing and anti-sloshing materials are investigated for mitigation of impact-induced damage. The integration of these systems, for the prevention of fire or explosion due to impact or bullet damage, may significantly improve the safety of aerospace fuel tanks. Leakage, after bullet penetration or debris impact, may be prevented or at least limited if the container's walls are made by materials with self-healing capabilities. The aim of this work is to define the self-healing behavior of the EMAA ionomer (poly-Ethylene-MethAcrylic Acid copolymer), with reference to the energy dissipation mechanisms involved during damage and autonomic healing. An experimental investigation on the healing capacity of the material when perforated by bullets shot at medium velocity (250 m/s-450 m/s) was carried out. In these tests, the influence of friction, temperature, and multiple impacts on the healing process was examined and discussed. Moreover, the material response in operating conditions similar to those encountered in actual aeronautical applications, that is, in presence of pressurized fluid and anti-sloshing material (Explosafe (R)) was tested. Results show that the presence of the liquid increases the self-healing capabilities, which are, however, slightly affected by pressurization and internal anti-sloshing filler; the contribution in terms of sloshing reduction remains relevant.