基于ALE方法的弹体入水硬质聚氨酯泡沫缓冲器降载性能分析

Analysis of load reduction performance of polyurethane buffer devices for projectiles entering water at high speed based on ALE method

针对弹体高速入水过程中的降载问题,设计一种硬质聚氨酯泡沫缓冲器。基于霍普金森压杆实验技术,获取冲击载荷下硬质聚氨酯泡沫密度和应变率效应,构建其宏观本构模型。采用拉格朗日-欧拉流固耦合方法(ALE),建立弹体入水冲击数值仿真模型,验证所建本构关系及ALE方法的合理性,对加装缓冲器的弹体高速入水问题进行数值仿真计算,获得入水过程中硬质聚氨酯泡沫的动态破坏过程及弹体运动参数,从而分析硬质聚氨酯泡沫密度、厚度对降载特性影响规律,讨论不同入水速度下硬质聚氨酯泡沫参数的设计方法。研究结果表明:硬质聚氨酯泡沫动态力学性能应变率效应不明显,但密度效应明显,缓冲降载性能随硬质聚氨酯泡沫密度和厚度的增大而升高。

A rigid polyurethane foam(RPUF)buffer was designed to reduce the load of a projectile during high-speed water entry.Based on the Hopkinson compression bar technique,the density and strain rate ef⁃fects of RPUF under impact loading were obtained,and its macroscopic constitutive model was established.Based on the Arbitrary Lagrangian-Eulerian(ALE),the numerical simulation model of the projectile during high-speed water entry was established.The numerical simulation of the projectile during high-speed water entry with different densities of RPUF was carried out.The dynamic failure process and motion parameters of the buffer during the water entry were obtained,and the influence law of the density and thickness of RPUF on the load reduction characteristics was analyzed.It can be found that the strain rate effect of RPUF is not obvious,but the density effect is obvious,and that,as the density and thickness of RPUF increase,the load reduction performance of RPUF increases.