Numerical investigation of impact-induced damage of auxiliary composite fuel tanks on Korean Utility Helicopter

This study analysed the impact-induced damage on the auxiliary composite fuel tank of a Korean Utility Helicopter. A coupled Eulerian-Lagrangian method was applied to consider the sloshing of fuel inside the tank. The composite damage modes were contemporarily considered by applying the Hashin failure criteria. We found that the degraded area due to the large and global deformation of the fuel tank generally decreases as the amount of fuel increases. However, the completely failed area due to the large and global deformation was altered by the strengths dominantly reflected into Hashin failure criteria. Meanwhile, the local damage and failure near the impact point generally increase due to the repulsive force induced by the inertia of the fuel as the amount of fuel increases. Accordingly, the impact behavior and damage according to the amount of the fuel will be used to build the basic data for bird strike tests and safety assessment of liquid-filled composite tanks.