基于ALE方法的航行体高速入水缓冲降载性能数值研究

针对航行体高速入水过程中的降载问题，设计了缓冲组件模型，并采用有限元任意拉格朗日-欧拉（ALE）的流固耦合方法，建立精确数值计算模型，对安装缓冲组件的航行体高速入水问题进行数值计算分析，获得入水过程中缓冲罩壳与缓冲泡沫的动态破坏过程及航行体运动参数，从而分析不同缓冲方案的缓冲性能。结果表明已设计的缓冲组件在航行体入水时能够吸收一定的冲击能量发生破坏并及时脱离航行体，同时缓冲泡沫的分层设计改变了缓冲罩壳的破坏方式，使罩壳破坏时间提前；撞水时在罩壳的头部与预设沟槽处会出现明显的应力集中，并且罩壳的沟槽设计能有效的引导其破坏形态，分层后的缓冲泡沫不易完全破坏，出现了二次缓冲的现象；缓冲组件使航行体入水速度曲线变化更加平缓，相同时间内航行体位移更大，分层缓冲泡沫方案降载率可达73.2%，缓冲效果较单层泡沫方案更好。

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

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.