装药结构试验器设计和低温老化试验研究

Design of Charge Structure Tester and Test of Low-temperature Aging

目的探索固体火箭发动机装药低温老化试验方法和机理,为固体发动机寿命预测和延寿提供支撑。方法设计方便取样测试的结构试验器,通过仿真计算确定具有一定应变水平的装药内孔尺寸,开展-10℃和-35℃低温老化试验。老化后首先对结构试验器进行无损检测,再取出药柱制取推进剂标准试样,进行常温和低温快速拉伸力学性能测试。结果设计完成三段连接式结构试验器,既不破坏药柱所承受的应力载荷,又保证取样方便、安全。无损探伤表明,经过低温长期贮存的结构试验器药柱没有产生裂纹和脱粘现象。推进剂的常温力学性能无明显变化,低温的最大抗拉强度有所升高,最大伸长率降低明显,-10℃和-35℃低温老化试验后,最大伸长率分别降低了24%和40%。结论推进剂内部产生了微损伤,承受低温快速应变(对应低温点火冲击状态)能力下降明显,应引起高度关注。

Objective To explore method and mechanism on low-temperature aging test for charge structure of solid rocket engine and provide support for predicting and extending the service life of solid engine. Methods Structure tester was designed to facilitate experimental testing through simulation to determine the strain of certain level of charge pore size, and low-temperature aging test was carried out at-10 ℃and-35 ℃. Non-destructive test was carried out to the structural tester after aging. Then the grain was taken off to prepare propellant sample to conduct fast tensile mechanical property test at room-temperature and low-temperature. Results A three-section connection type structure tester was designed to make sure not to destroy the stress load of the grain born and to ensure the sampling convenience and safety. The non-destructive testing showed that the grain inside the structure tester did not produce cracks and debonding phenomena after being stored at low temperature for a long term; the mechanical properties of the grain at room temperature had no significant change; the maximum tensile strength at low temperature was increased to some extent and the maximum elongation decreased significantly. After low-temperature aging test at-10 and ℃-35 ℃, the maximum elongation decreased by 24% and 40% respectively. Conclusion Micro-damage produces inside the propellant and the capacity to withstand low-temperature rapid response（corresponding to low-temperature impact ignition state） decrease significantly, which should cause great concern.