基于Nataf变换的载荷相关系统风险预测方法

Method for Syetem Risk Prediction with Load Dependency Based on Nataf Transformation

以元件安全裕度为基本随机量,基于Nataf变换建立载荷相关系统共因失效概率定量分析的非经验模型,实现原始概率空间向独立标准正态空间的映射,从而把共因元件组的联合失效概率值转化成一维标准正态积分的乘积。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,提出载荷相关系统风险预测的实用方法。该模型与方法直接体现共因失效内在机理,克服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,为复杂系统风险数据分析及概率预测提供了新途径。

An un-empirical model for probability quantitative analysis of common cause failures is demonstrated that utilizes Nataf transformation approach based on safety margin variables of components in a common cause group. The joint failure probability is figured out by multiplying the products of the individual integration in an independent, normal space. In view of the fact that the data of system low-order common cause failure are known while the system load distribution and components strength distribution are unknown, a practical method for risk prediction of load-dependency systems is put forward. The proposed model and method embody the inherent mechanism of common cause failures and overcome the limitation of traditional model which excessively relies on historical data or subjective experience while neglects the occurrence and action rule of common cause failures. The proposed method provides complicated systems with a new way to risk data analysis and failure probability prediction.