Steel Structure Impacting onto Water: Coupled Finite Element-Smoothed-Particle-Hydrodynamics Numerical Modeling

Ditching in emergency conditions is an important issue for a safe transport plane. Because of the different distributions of loads on the structure, the solutions implemented to secure safety during an impact on the ground are often ineffective in the case of an impact on water. To improve the understanding of the impact dynamics between water and a metallic structure, the Italian Center of Aerospace Research started a preliminary experimental campaign aimed to test the behavior of a simple mockup structure during a water impact. The test specimen was instrumented with accelerometers and pressure sensors linked to a high-speed data acquisition system able to record the time histories to be used for different numerical simulations. Such numerical simulations have been carried out, with different software, both at the DLR, German Aerospace Center and at the Department of Aerospace Engineering at the University of Naples "Federico II". The paper presents the results obtained by using the explicit finite element code LS-DYNA in numerically reproducing each experimental test to define the laws of the materials and correctly simulate the structural behavior under study. The fluid region was modeled using the smoothed-particle-hydrodynamics approach, obtaining a satisfactory numerical-experimental correlation. [PUBLICATION ABSTRACT]