不完整结构系统刚度可靠性分析

Reliability analysis of imperfect structural system stiffness

基于结构强度可靠性分析的基础之上,提出了不完整结构(结构系统中有部分元件已失效,但结构未变成机构仍具有一定的承载能力)刚度可靠性的分析方法。该方法考虑了元件因强度失效对结构系统刚度可靠性的影响,以条件概率的形式给出了不完整结构因刚度失效所对应的模式失效概率。并且导出了条件概率所对应的等效安全余量的形式,进而计算在各失效历程中的各失效模式之间的相关性和刚度失效概率。算例表明这样分析符合结构在变成机构之前在使用各阶段刚度可靠性的真实情况,为结构的合理利用起指导作用。

Based on reliability analysis method of structural strength.The reliability analysis method of imperfect structural stiffness is proposed.In this paper,the imperfect structure is defined as structure of partial elements failure,but the structure does not yield a collapse mechanism and still has bearing capability.This method considered failure of element as strength influencing on the reliability of imperfect structural stiffness.Failure probability of imperfect structural stiffness was given in the form of conditional probability.Equivalent safe margin of conditional probability was induced;accordingly relativity of failure modes and failure probability of stiffness could be calculated at the each failure state.A numerical example is analyzed.It is showed that such analysis is suitable for real reliability cases at the each failure state before the structure yield a collapse mechanism.The results are instructive for structures in rational use.