非平稳随机地震作用的结构整体可靠度分析

应用随机过程的正交展开-随机函数方法,建立了非平稳地震动过程的概率模型,实现了用一个基本随机变量来表达地震动过程的目的。通过选取基本随机变量的代表性离散点集,可以直接获取地震动过程的代表性样本集合。结合概率密度演化理论,进行了多自由度Duffing系统的随机地震反应分析与抗震可靠度计算。研究表明,非平稳地震动过程的概率模型与概率密度演化理论有机结合,可以实现复杂工程结构整体抗震可靠度的精确计算。

GLOBAL RELIABILITY ANALYSIS OF STRUCTURES UNDER NON-STATIONARY RANDOM EARTHQUAKE EXCITATIONS

Referring to the orthogonal expansion & random function of stochastic processes, the probabilistic model of non-stationary ground motion processes is established, and the earthquake ground motion can be represented using a basic random variable. The representative discrete point set of the basic random variable can be selected, and the representative sample ensemble for non-stationary ground motion processes can be directly generated by the probabilistic model. The proposed earthquake probability model provides an opportunity to employ the probability density evolution method (PDEM) to study the stochastic nonlinear responses and seismic reliability of general structural systems. An example, which deals with a non-linear MDOF Duffing system subjected to random earthquake excitations, is investigated to validate the above approach.