摘要
为分析热老化后三组元端羟基聚丁二烯(HTPB)推进剂在低温动态准双轴加载下的性能,开展了不同热加速老化时间、不同温度和应变率条件下推进剂的准双轴拉伸力学性能试验及扫描电镜(SEM)观察试验。试验结果表明:热加速老化前后,推进剂的拉伸曲线趋势、力学性能变化规律及细观损伤形式保持一致,改进型非线性模型能够更好地描述1~100 s-1应变率范围内典型力学性能参数随热老化时间的非线性变化关系。随温度降低,老化后推进剂的断面形貌由"脱湿"变为AP颗粒断裂,热老化、低温以及高应变率载荷的叠加使得推进剂的细观损伤变得更加严重,但准双轴拉伸时损伤程度相比单轴拉伸时有所减弱。热老化32 d、74 d和98 d后-50℃、14.29 s-1加载条件下的最大伸长率分别为未老化时室温、0.40 s-1条件下数值的28.79%、27.58%和25.63%,该参数定义可为分析长期贮存后战术导弹SRM药柱在低温点火条件下结构完整性失效的准则提供数据支持。
To investigate the thermal aged properties of tri-component hydroxyl-terminated polybutadience(HTPB) propellant at low temperatures under dynamic quasi-biaxial loading, the quasi-biaxial tensile mechanical tests and scanning electron microscope(SEM) analysis are carried out at different thermal accelerated aging time, temperatures and strain rates. The results indicate that the tendency of stress-strain curves, variation of mechanical properties with loading conditions and fracture mechanism for the propellant are consistent with each other before and after aging. Moreover, the nonlinear relationships of the typical mechanical parameters and thermal aging time can be more reasonably described with the improved nonlinear model at the strain rates from 1 s-1 to 100 s-1. As the temperature decreasing, the fracture mechanism of the aged HTPB propellant changes from dewetting to AP particles fracture. The coupled effects of the thermal aging, low temperature and high strain rate induce more serious damage of the propellant. However, the damage of the aged propellant under quasi-biaxial tension is weaker, compared with that at the same temperature and strain rate in uniaxial tension. The value of this mechanical parameter at-50 ℃ and 14.29 s-1 after aging for 32 d, 74 d and 98 d reduces to 28.79%, 27.58% and 25.63% of the value at room temperature and 0.40 s-1 before aging, respectively. Therefore, the maximal elongation of HTPB propellant under quasi-biaxial tension can be selected as the failure criterion for analyzing the structure integrity of the propellant grain for tactical missiles during ignition of SRM after long periods of storage.
作者
刘畅
王哲君
强洪夫
徐卫昌
韩奎侠
LIU Chang;WANG Zhe-jun;QIANG Hong-fu;XU Wei-chang;HAN Kui-xia(Qingzhou Hi-Tech Institute,Qingzhou 262500,China;Xi’an Hi-Tech Institute,Xi’an 710025,China)
出处
《宇航学报》
EI
CAS
CSCD
北大核心
2020年第3期353-361,共9页
Journal of Astronautics
基金
国家自然科学基金(11772352)
“十三五”装备预研领域基金(61407200203)。
关键词
低温
动态加载
热加速老化
固体推进剂
准双轴拉伸
Low temperature
Dynamic loading
Thermal accelerated aging
Solid propellant
Quasi-biaxial tension
