水陆两栖飞机水上降落属于复杂的流固耦合问题，文中建立了某水陆两栖飞机机头的入水流固耦合模型，采用耦合的欧拉 － 拉格朗日(CEL)算法分析了机头入水瞬时的结构动力响应，对比了不同入水角度和不同垂直速度下机头的应力、冲击力及质心速度变化． 结果表明:机头入水初期船底冲击力即出现峰值，之后随着机头抬高，船底冲击力将再次出现峰值;入水过程中机头骨架受力变化明显;随着入水角度的减小，机头应力也减小;入水速度减小，机头应力和船底冲击力都随之减小．

Aiming at the water landing of amphibious aircrafts，this paper presents a fluid-structure interaction (FSI) model of a certain amphibious aircraft head and analyzes the transient structural dynamic response of the head ditching by using the coupled Eulerian-Lagrange (CEL) method． Moreover，the stress，impact force and mass center velocity of the head at different ditching angles and vertical speeds are discussed． The results show that (1) the bottom pressure peak appears in the initial ditching stage and appears again with the heading up of the air-craft head; (2) during the ditching，the pressure of the head skeleton changes significantly; (3) with the de-crease of the hitting angle，the stress of the head reduces; and (4) both the head stress and the bottom impact force reduce with the decrease of ditching speed．