Test and numerical analysis for water entry of elastic cabin from amphibious aircraft

Abstract

Water-entry performance of amphibious aircraft is one of the main factors affecting the structural design. However, it is analyzed by rigid models in general, which is difficult to reflect the elastic characteristics of the structure. And it is difficult to obtain sufficient guidance for structural design from rigid-body analysis. In this study, water-entry model of an elastic cabin from amphibious aircraft was developed using the Arbitrary Lagrangian-Eulerian (ALE) method and validated by a designed 1:1 cabin water-entry test. Analysis under various conditions revealed the cabin's dynamic response in three steps: (1) the keel of the cabin section touches the water, (2) the bottom skin is wetted, and (3) the bottom skin is submerged. This study also compares the rigid-surface crashes and water-entry impacts of the cabin from the point of view of load and energy analysis. The results show that rigid-surface crash mainly affects bulkhead and keel, whereas water-entry energy is mainly absorbed by the skin, connectors, and stringers. Additionally, varying skin thicknesses showed a negative correlation with back surface deformation. The methodologies and conclusions presented in this study can offer valuable references for researchers in the field of water entry.