Numerical study on load-shedding performance of a high-speed water-entry vehicle based on an ALE method

Abstract

Aiming at the problem of load shedding in high-speed water entry of a vehicle, a composite structural buffer has been designed. Meanwhile, an accurate numerical model with the fluid-solid coupling is established to analyze the crushing process based on the arbitrary Lagrangian-Eulerian (ALE) algorithm and evaluate the effects of different schemes. The results show that the designed buffer can absorb the impact energy, leading to the damage and separation from the vehicle properly. The layered design of cushion foam changes the damage mode of the nose cap and causes it to be failure in advance. When the buffer is in contact with water, stress concentration occurs at the top of nose cap and preset groove. The groove effectively guides the destruction mode of the cap, such that the layered foam will not be too easy to be completely destroyed and the phenomenon of secondary cushion can occur. The velocity curve of the vehicle with the buffer changes more smoothly, the displacement is greater in the same time, and the load reduction rate of the layered foam scheme can reach 73.2% which is better than the single-layer foam scheme.