Evaluation of the Arbitrary Lagrangian-Eulerian method (ALE) for the simulation of fluid structure interaction during aircraft ditching events

Ditching is one of the possible scenarios for the aircraft's, it is an emergency landing on the water by an aircraft not designed fo this purpose. Since a ditching is a controlled landing, the pilot prepares the aircraft in the best possible attitude for impact, also initiating procedures for passengers through the crew. The ditching counts 4 phases: approach, impact landing and floatation. This study focuses on the impact and landing. During the impact, following the recommended layout, the first part impacting the water is the rear bottom part of the fuselage, it is the highest load phase for the aircraft, then in the landing phase, hydrostatic phenomena occur. Due to the difficulty of the experimental tests, numerical simulations can help to predict the consequences od the fluid-structure interaction. The purpose of this study is the assessment of one of the numerical methods, the Arbitrary Lagrangian-Eulerian (ALE) method to simulate ditching events using the software LS-DYNA. In the first part of the study a simple model is investigated to get familiar with ALEm then two panel are studied, the first one is a flat panel and the second one is a double curved panel, at the end an entire aircraft is simulated. Most of the results obtained are compared to experimental data to understand the accuracy of the ALE method. All the models have been generated by a software framework for the aircraft structural analysis developed by DLR based on Python language, called Parametric Numerical Design and Optimization Routines for Aircraft (PANDORA).