低温下叠氮聚醚推进剂冲击损伤特性与动态力学性能

摘要

The impact load was applied to azido polyether propellant by the instrumented drop hammer device at-40 ℃.The impact damage of the sample was characterized by X-ray micro-tomography (X-μCT),and the dynamic mechanical properties of the propellant sample were studied by dynamic mechanical analyzer at different loading frequencies.Results show that the dynamic mechanical properties of azido polyether propellant exhibit obviously loading frequency-dependent and the glass transition temperature increases from-38.1 ℃ to-23.1 ℃ when the loading frequency varies from 1 Hz to 20 Hz.The propellant samples have no macroscopic crack with the impact energy below 2 J, but part of the perchlorate amine(AP) particles inside have been broken;and the propellant samples break with the impact energy increasing.The test curves of broken samples contain unstable crack growth which indicates the partial brittle material character of azido polyether propellant.The whole process of the fracture of azido polyether propellant is that the initial micro cracks was formed in the AP particles with defects, extend to large macroscopic cracks in the basal body, and then the propellant samples broke.%利用仪器化落锤冲击试验机在-40 ℃下对叠氮聚醚推进剂进行了冲击加载模拟实验,通过X射线微层析成像技术(X-μCT)表征了推进剂的冲击损伤特性,并采用动态力学分析研究了叠氮聚醚推进剂在不同加载频率下的动态力学性能.结果表明,叠氮聚醚推进剂动态力学参数表现出显著的加载频率依赖性,当加载频率由1 Hz增大至20 Hz时,其玻璃化转变温度由-38.1 ℃升高至-23.1 ℃;相应测试条件下,推进剂试样在冲击加载能量不低于2 J时发生断裂,未冲断推进剂无宏观裂纹产生,但其内高氯酸铵(AP)颗粒已部分破碎;被冲断试样冲击曲线中包含不稳定裂纹扩展过程,表明叠氮聚醚推进剂在低温下具有一定的脆性材料特征,推测其损伤模式为含缺陷的AP颗粒首先发生穿晶断裂,初始微裂纹扩展于基体中并相互贯通扩大,最终导致试样断裂.