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导弹在贮存期内要反复经历运输、存放、检测、维修和战备值班等过程,其环境温度并不恒定,而是在一定范围内发生动态变化。对性能参数有变化趋势的弹上部件而言,有必要考虑环境温度变化对其可靠性的影响,因此提出一种非恒定温度剖面下的贮存可靠性评估方法。首先,分析产品实际性能退化的特点,选择带有非线性漂移项的Wiener过程描述产品的退化性能,推导出试验环境下产品的寿命分布。然后,采用Gamma分布拟合贮存期间的弹内温度分布。进而利用比例风险模型描述温度变化对产品可靠性的影响,推导弹上性能退化型部件在非恒定温度剖面下的无条件寿命分布,并给出模型参数的极大似然估计。算例表明本方法实际可行。
During the storage period, the missile repeatedly undergoes the processes of transportation, storage, testing, maintenance, and readiness for combat readiness. The ambient temperature of the missile is not constant, but changes dynamically within a certain range. It is necessary to consider the influence of the ambient temperature on the reliability of the missile components that have the trend of variation in performance parameters. Therefore, a method of evaluating the storage reliability under non-constant temperature profile is proposed. Firstly, the characteristics of product degradation are analyzed. The Wiener process with nonlinear drift term is chosen to describe the degradation performance of the product. The life distribution of the product under the test environment is deduced. Then, the Gamma distribution is used to fit the distribution of in-bomb temperature during storage. Then, the proportional hazards model is used to describe the influence of temperature variation on the product reliability. The unconditional life distribution of degenerative parts on the projectile is deduced under non-constant temperature profile, and the maximum likelihood estimation of the model parameters is given. The example shows that this method is feasible.