Fluid-structure interaction of water filled tanks during the impact with the ground

Crashworthiness of subfloor-integrated tank is fundamental for the survivability of an impact with the ground in emergency. In this paper, numerical models for the analysis of the water sloshing in a tank during the impact with the ground have been developed and validated using experimental data. Specific drop tests were carried out using simulacra of a tank integrated in the subfloor of a small dimension helicopter and reproduced in detail using LSTC LS-Dyna. In particular, four different models were developed for the water inside the tank-namely: Finite Element (FE), Eulerian, Arbitrary Lagrangian Eulerian, and Smoothed Particles Hydrodynamics (SPH) model. Advantages and disadvantages of these models were evaluated and the results show that the FE model of the water is the most feasible for the analysis of the tank structure damages whereas the SPH model of the water, despite the large required CPU time, is the most feasible for the analysis of the sloshing of the water.