系统共因失效概率分析的非经验模型

An Un-empirical Model for Probability Prediction of Common Cause Failures in Systems

根据载荷-强度干涉理论,探讨了系统共因失效发生及作用机理,揭示了元件强度统计独立时由系统共因载荷引发元件失效相关的基本规律。采用相关系数建立了共因载荷随机变量方差、元件强度随机变量方差以及失效相关程度之间的近似关系,并导出系统共因失效概率定量分析的非经验模型。针对系统低阶共因失效数据已知而系统载荷分布及元件强度分布未知的现实条件,提出了计算系统共因失效概率的实用方法。该模型与方法直接体现了共因失效内在机理,克服了传统模型过多依赖历史数据或主观经验而忽略共因失效发生及作用规律的局限,为冗余系统风险数据分析、概率预测,特别是可靠性设计提供了新途径。

The generating and coupling mechanism of common cause failures was studied based on load strength interference theory and the regularity of the common load giving rise to element failure dependency whereas strengths of components were independent was brought to light. Establishing the relationship among the common load variance, component strength variance and component failure de- pendency by correlation coefficient, an un empirical model for probability prediction of common cause failures was derived. Considering the facts that low-order failure data being known and distributed functions of common load and component strength being unknown, a practical method for com- mon cause failures probability assessment was put forward. Different from the conventional model, the new model and method embody the inherent mechanism of common cause failures with overcoming shortages of depending field data or subjective experience too much, which gives a new path for risk data analysis, failure probability prediction and reliability design of redundant systems.