立式贮存固体火箭发动机装药可靠性及影响因素研究

Research on Reliability and Influencing Factors of Solid Rocket Motor Grain Under Vertical Storage

关键词:  固体发动机  立式贮存  加速老化试验  随机有限元  可靠性  灵敏度分析

Key words:  Solid motor  Vertical storage  Accelerated aging test  Stochastic finite element  Reliability  Sensitive analysis

摘要:

立式贮存是固体发动机的一种特殊贮存状态，为研究其对发动机药柱贮存可靠性的影响，开展推进剂在不同老化时间和不同贮存温度的加速老化试验，获取贮存温度下推进剂力学性能的变化规律；开展发动机经温差、重力和弹射增压联合载荷作用下的确定性有限元分析，获取药柱的Von-Mises应变危险点位置；开展发动机实测振动载荷数值模拟，计算发动机动态立贮累积损伤。而后利用蒙特卡洛随机有限元分析，进行不同老化时间下的发动机经不同立贮次数后点火发射的数值仿真，获取药柱可靠度随立贮次数的变化规律；最后进行灵敏度分析，获取不同工况下各参数对可靠性的重要度排序。结果表明：药柱点火可靠度与立贮次数之间可用负指数函数进行表示，以0.9为可靠性下限，老化0、5、10和15年后发动机可允许的动态立贮次数分别为19、11、2和0次。

Abstract:

Solid rocket motor under vertical storage is a special state，in order to study its influence on the storage reliability of grain, the accelerated aging test of propellant under different aging year and storage temperature is carried out, so as to obtain the variation rules of propellant’s mechanical property at storage temperature; The deterministic finite element analysis of motor under the combination of temperature difference, gravity, ejection overload and pressure is carried out, and the dangerous location of grain’s Von-Mises strain is also obtained, then the cumulative damage under dynamic vertical storage of the grain is calculated by the numerical modeling of motor under actual vibration loadings. Then, the Monte Carlo stochastic finite element analysis is used to conduct the numerical simulation of motor’s blast-off during different aging year and vertical storage times, and the variation rules of reliability with vertical storage times is obtained. Finally, sensitive analysis is carried out to acquire the order of importance of all parameters on reliability at different conditions. Result shows that it can be represented by a negative exponential function between the ignition reliability and vertical storage times, the allowable dynamic vertical storage times of the motor with 0.9 reliability lower limit during 0, 5, 10 and 15years of aging time is 19, 11, 2, and 0.