冗余结构系统共因失效相关性分析及概率预测

ANALYSIS FOR DEPENDENCY OF COMMON CAUSE FAILURE AND PROBABILITY PREDICTION IN REDUNDANT STRUCTRAL SYSTEMS

通过分析冗余结构系统环境载荷和元件强度分散度对系统各失效模式之间相关程度的不同影响,阐明了元件强度变量相互独立时冗余系统共因失效的发生机理,揭示了共因失效这种系统失效相关性的最基本原因。通过系统1、2重失效概率近似表达了系统各重失效概率的下限,并在此基础上建立考虑共因失效的冗余结构系统概率预测模型,利用JC方法的分析结果近似预测单位时段冗余系统的失效概率。

Through analysis the effects of deviation of the component strength and the common environment load to each failure mode in redundant structural systems, the mechanism of common cause failures when all components strength variables are independent is illustrated. As a kind of dependent failures, the basic root cause of common cause failures is discussed in detail. Using the results of JC method, the multiplicity failure probability of systems can be expressed approximately by component individual failure probability and 2-class union failure probability. An approximate approach to failures probability estimation is developed. By means of the new model derived from environment load-component property analysis, common cause failures probability of r-out-of-n: g systems can be easily evaluated. An example is given to show availability and effectiveness of the method. The results of calculation and Monte Carlo simulation are in good conformity to each other.