基于首次超越破坏时间概率的结构动力可靠性分析

The reliability analysis of structures based on failure probability of first-passage time

对结构非线性动力系统的首次超越破坏(失效)进行研究。首先,采用等效线性化与随机平均方法,推导出了首次超越破坏时间的结构失效概率分布函数,并对单自由度非线性体系的失效概率进行了分析。其次,采用虚拟激励法对多自由度滞变结构体系进行了随机响应计算,结合首次超越准则(双侧界动力界限),研究了随机地震激励下高层结构的各楼层与结构整体可靠度。研究表明:在激励和破坏界限值相同的情况下,非线性体系的首次超越破坏时间概率要比相应线性体系的小;并发现了在随机地震激励下高层结构的薄弱层楼层的位置。该方法对结构的性能设计与控制具有指导意义。

The first-passage failure of a nonlinear dynamic system is studied.The failure probability density function of the first-passage time is derived by using the equivalent linearization and stochastic average method,and the failure probability of a single degree-of-freedom nonlinear system is analyzed.The random seismic response of multi-degree-of-freedom hysteretic structure system is investigated using pseudo excitation method.Based on the first passage criterion,the reliability index of each floor and the whole structure of hight-rise structure are calculated.Research shows failure probability of first-passage time of nonlinear system is smaller than the corresponding linear system in case of exciting and damage values are the same.The weak floor of the structure can be found by using this method.This method is instructive for structural performance design and state control.