基于性能退化数据的液体火箭发动机可靠性Bayes评定

The Bayes Reliability Assessment for Liquid Rocket Engine Based on Performance Degradation Data

性能退化表征的是产品的工作能力随时间逐渐降低的现象。对于液体火箭发动机等试验费用昂贵的高可靠性产品,失效时间数据难以得到,此时性能退化数据是评定其可靠性的重要信息。文章提出用线性随机过程模型来描述产品性能参数逼近临界值的过程,再根据产品的失效机理,推导出产品的失效分布函数形式。相对于传统的寿命分布模型,文中推导的失效分布函数中的参数因物理含义明确而易于通过实时跟踪测量性能参数时间序列数据估计得到。文中还通过一个数值实例说明了该方法在工程上应用的有效性。

Degradation is a phenomenon where certain measurements of quality characteristics deteriorate over time. Degradation test is a useful technique to provide information about the lifetime of highly reliable products. The item under inspection may still be useable and the amount of deterioration, properly measured, can provide us with useful information. In this paper, the degradation data are described as a simple linear stochastic process model, the parameters under the model can be estimated from the data collected, and using some related stochastic process theory, the failure time distribution can be obtained. The data needed for this model are easy to obtain in reality, so the proposed model is convenient to use for engineers. At last a numerical example is given to illustrate the efficiency of this model.