目的 确定空投水囊的厚度以及提高空投水囊成功率。方法 基于ANSYS/LS_DYNA有限元分析软件，建立聚氨酯(TPU)水囊组合件三维仿真模型，对其空投跌落冲击3种类型地面过程进行仿真，优化囊体厚度，分析地面倾斜时水囊组合件的跌落冲击情况，并通过与已有试验数据的对比验证了该仿真方法的有效性。结果 仿真计算表明，3 mm厚度的TPU水囊可以抵御水囊组合件的跌落冲击而不破损。水囊组合件跌落冲击混凝土、沙地和草地时，水囊所受冲击应力集中在下层水囊的两侧中部，沙地对水囊缓冲最为明显，所受应力大约是混凝土地面的1/4;在混凝土地面倾斜时，水囊所受冲击应力会相应增加，为了保证该水囊组合件的安全空投，地面倾斜角度不应超过12°。结论 利用有限元仿真分析空投水囊跌落冲击是可行、有效的，可应用于空投水囊的安全性设计与评估。

The work aims to determine the thickness of water sac and improve the airdrop success rate of water sac. A three-dimensional simulation model of polyurethane (TPU) water sac assembly was established based on ANSYS/LS_DYNA finite element analysis software. Three kinds of ground processes of water sac airdrop impact were simulated. The thickness of the water sac was optimized. The drop impact of the water sac assembly was analyzed when the ground was inclined. The validity of the simulation method was verified through comparison with the existing experimental data. The simulation result showed that the polyurethane (TPU) water sac with a thickness of 3 mm could resist the drop impact of the water sac assembly without damage. The impact stress region of the water sac was located in the middle of both sides of the lower water sac when it fell and impacted concrete, sandy land and grassland. Sandy land had the most obvious buffer effect on the water sac, and the stress was about 1/4 of that of concrete; When the concrete ground was inclined, the impact stress of the water sac would increase correspondingly, To ensure the safe airdrop of the water sac assembly, the ground incline angle should not exceed 12°. It is feasible and effective to analyze the drop impact of airdrop water sac by finite element simulation, which can be applied to the safety design and evaluation of airdrop water sac.