基于概率密度演化理论的结构抗震可靠性分析

运用随机过程的正交展开方法，将地震动加速度过程表示为由10个左右的独立随机变量所调制的确定性函数的线性组合形式。结合概率密度演化方法和等价极值事件的基本思想，研究了非线性结构的抗震可靠度分析问题。以具有滞回特性的非线性结构为例，对某一多自由度的剪切型框架结构进行了抗震可靠性分析。结果表明：按照复杂失效准则计算的结构抗震可靠度较之结构各层抗震可靠度均低。这一研究为基于概率密度函数的、精细化的抗震可靠度计算提供了新的途径。

Aseismatic reliability analysis of nonlinear structures based on probability density evolution method

Employing the orthogonal expansion method, earthquake acceleration process is represented as a linear combination of deterministic functions modulated by 10 independent random variables. So, it is natural to combine the probability density evolution method (PDEM) and the orthogonal expansion of seismic ground motion to study the nonlinear stochastic earthquake response. Furthermore, the aseismatic reliability of structures is assessed using the idea of equivalent extreme-value, which can be used accurately to evaluate structural systems under compound failure criterion. A hysteretic nonlinear structure is taken as an example. The failure probability and reliability of the nonlinear shear frame structure with 10 degrees of freedom subjected to stochastic ground motions are investigated. The result indicates the system reliability of the structure is lower than the reliability of each story. The investigation shows that the proposed approach is of fair accuracy and acceptable efficiency for seismic reliability.