Helicopter Subfloor-Integrated Fuel-Tank Crashworthiness

Water impact of a helicopter in emergency is likely to have tragic consequences. In view of that, numerical models to predict helicopter crash performance during a water impact are of paramount importance. In this paper, the crash behaviour of a (half filled) helicopter subfloor-integrated fueltank has been numerically investigated. The finite elements model of a fuel-tank simulacrum was developed and validated referring to the data collected during ground impact drop-tests and hence used to investigate the crash performances of a fuel-tank with regard to the impact with a rigid and a fluid surface. The difficulties in modelling a fluid when using explicit codes based on finite element method suggested adopting two different approaches to model the fluid regions: Lagrangian and Arbitrary Lagrangian Eulerian. Advantages and disadvantages of these approaches have been highlighted. Referring to the numerical results obtained, the differences between ground and water impact have been eventually discussed.