枚举结构主要失效模式的改进分枝限界法

DEVELOPED BRANCHING AND BOUNDING METHOD FOR ENUMERATING STRUCTURAL SYSTEM DOMINANT FAILURE MODES

在对大型复杂结构进行可靠性分析时 ,主要失效模式的枚举对于确认结构的危险部位以及提高结构系统失效概率的计算效率具有非常重要的意义。文中对分枝限界法进行改进。改进后的分枝限界法可以删除“伪失效模式”和重复的失效模式 ,降低了枚举次要失效模式的可能性 。

Enumerating dominant failure modes of large-scale complex structural system is very important to identify the possible failure positions of a structure and improve the efficiency of the procedure for calculating failure probability of the structural system. Based on thorough investigation, this paper developed Branching and Bounding Method (BBM). The first development is that the system failure probability P (k) fs(k=1,2,...,n) of the kth level dominant failure paths in a fault tree is employed to eliminate the defect of using the failure probability of single dominant failure mode astruncation criterion. The second development is that the concept of 'False Dominant Failure Modes (FDFM)' is discussed and a criterion is given to delete the FDFM in a fault tree. The third development is that the concept of Minimum Cut Set is introduced to delete the repeated the failure modes. The developed BBM can reduce the possibility of enumerating non-dominant failure modes, repeated failure modes and false failure modes, and improve the enumeration efficiency of dominant failure modes of large-scale structural system.