定应变下固体火箭发动机药柱概率贮存寿命预估研究

Study on Probabilistic Storage Life Prediction of SolidRocket Motor Grain under Constant Strain

关键词:  固体火箭发动机  定应变  概率贮存寿命  随机有限元法  可靠性

Key words:  Solid rocket motor  Constant strain  Probabilistic storage life  Stochastic finite element method  Reliability

摘要:

为研究定应变对固体火箭发动机药柱概率贮存寿命的影响，对推进剂高温加速老化力学性能数据进行了统计分析，利用随机有限元法分析了发动机药柱在内压和过载的联合作用下Von Mises应变的均值和标准差，采用应力-强度干涉模型计算了药柱结构可靠性随应变敏感系数的变化趋势，据此分析了定应变对发动机药柱概率贮存寿命的影响。结果显示，定应变对发动机药柱概率贮存寿命影响显著，以0.97为可靠性下限，当应变敏感系数为2.94时，其寿命约为30.98年，应变敏感系数为-2.94时，其寿命约为0.92年，在此范围，药柱概率贮存寿命随应变敏感系数的增大而延长。

Abstract:

To investigate the effects of constant strain on the probabilistic storage life of solid rocket motor (SRM) grain, the digital characteristic of mechanical property parameters of solid propellant with storage time was derived from the statistical analysis of high-temperature accelerated aging test data. The mean and standard deviation of Von Mises strain of grain in the combined action of internal pressure and overload were calculated using stochastic finite element method (SFEM). The structure reliability of grain and its variation tendency under different strain sensitivity coefficient with storage time was calculated by using stress-strength interference model. On the basis of calculation results, the probabilistic storage life of the SRM grain under different constant strain was predicted with a lower limit of reliability coefficient of 0.97. Results show that the constant strain has an obvious effect on the probabilistic storage life of SRM grain. The probabilistic storage life was about 30.98 years when sensitivity coefficient was 2.94, and 0.92 years when sensitivity coefficient was -2.94. The probabilistic storage life of the grain increases as strain sensitivity coefficient increases in this interval.