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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。
The impact loading experiment of azide polyether propellants was carried out at -40 ℃ using an instrumentized drop-weight impact tester. The impact damage characteristics of the propellants were characterized by X-ray micro-tomography (X-μCT) The dynamic mechanical properties of azide polyether propellants at different loading frequencies were studied by dynamic mechanical analysis. The results show that the dynamic mechanical parameters of azido polyether propellants exhibit significant loading frequency dependence. When the loading frequency increases from 1 Hz to 20 Hz, the glass transition temperature increases from -38.1 ℃ to -23.1 ℃. Under the corresponding test conditions, the propellant sample fractured when the impact loading energy was not less than 2 J, and the unruptured propellant did not produce macro-cracks, but the particles of ammonium perchlorate (AP) were partly broken; The impact curve of the sample contains unstable crack growth process, indicating that azide polyether propellants have certain brittle material characteristics at low temperature. It is presumed that the damage mode is that AP particles with defects first undergo transgranular fracture, and the initial microcracks expand to The matrix and through each other to expand, eventually leading to specimen fracture.