低温高应变速率下复合固体推进剂损伤机理分析

Damage mechanism analysis of composite solid propellants under low temperature and high strain rate

针对机载战术导弹低温使用要求,开展了复合固体推进剂在-50℃环境中的单轴拉伸试验,拉伸应变速率介于0.05～150%/s之间,结合复合固体推进剂颗粒夹杂模型在不同拉伸速率下的损伤数值仿真结果,分析了推进剂力学性能在不同应变速率下的变化规律及损伤机理,并通过低温快慢组合拉伸试验进行了验证。结果表明,应变速率主要影响复合固体推进剂颗粒与基体之间产生初始损伤的界面数量和界面损伤演化速率,高应变率下形成初始损伤的界面数量增多,但推迟了颗粒脱湿损伤演化、聚合的进程,基体损伤占比增加,使得在低温环境中复合固体推进剂的应力-应变曲线"双峰"现象更加突出。

Based on the low temperature requirements of airborne tactical missiles, uniaxial tensile tests of composite solid pro- pellants were conducted at -50℃ and the tensile strain rates were between 0.05%/s and 150%/s.Then damage mechanisms of these composite solid propellants have been investigated on the numerical simulation results of packing models.The damage proces- ses and the curves of solid propellants stress-strain varying with strain rates at -50℃ have been analyzed as well. The damage mechanisms were verified by the high-low combined tensile tests. The results show the number of interfaees with initial damages be- tween the particles and binder.The damage evolution rates are determined by the strain rates of solid propellants.The initial number of damaging interfaces grow up with the strain rates, while the particle dewetting damage developing and polymerizing processes are delayed under lower temperature,which increases the level of binder damage.So it is clear that the bifid hump could be expressed under high strain rate and low temperature conditions.