结构随机动力激励的物理模型:以脉动风速为例  

PHYSICAL MODELS FOR THE STOCHASTIC DYNAMIC EXCITATIONS OF STRUCTURES:IN THE CASE OF FLUCTUATING WIND SPEED

作　　者：李杰[1,2] 阎启[1] 

机构地区：[1]同济大学建筑工程系,上海200092 [2]同济大学土木工程防灾国家重点实验室,上海200092

出　　处：《工程力学》2009年第A02期175-183,224,共10页Engineering Mechanics

基　　金：国家自然科学基金创新群体项目(50621062)

摘　　要：以脉动风速为背景,展示了基于物理建立结构动力激励模型的基本思想与具体路线。根据经典湍流理论,阐述了均匀剪切湍流中的惯性子区和剪切子区所服从的物理规律,并根据物理随机系统的基本思想,建立了形式十分简单的标准化随机Fourier波数谱模型。应用概率密度演化方法,得到了剪切子区与惯性子区分界位置lc的概率分布,统计给出了基本随机变量地面粗糙度z0和标准高度10min平均风速(h)的概率分布。研究表明:基于物理的随机Fourier波数谱理论预测结果与实测Fourier波数谱的均值曲线符合良好,可望为结构抗风设计与可靠度评价提供较为合理的动力输入模型。Taking fluctuating wind speed as example, this paper displays the basic method of modeling the structural dynamic excitation based on physical process. According to classic turbulence theory, the physical laws of inertial sub-range and shear sub-range in homogeneous shear turbulence are described. Along with the basic idea of physical stochastic system, a normalized stochastic Fourier wave-number model with simple format is established. The probability distribution of the boundary position of the shear sub-range and inertial sub-range is obtained by the Probability Density Evolution Method （PDEM） and the probability distribution of the basic variables including ground roughness z0 and 10-min mean wind speed U（h） are also obtained. The research shows that the mean spectrum of the theoretical prediction based on the physical process corresponds with the measured Fourier mean wave-number spectrum well. The model proposed here is expected to provide a reasonable excitation model for wind-resistant design and reliability analysis of structures.

关 键 词：物理模型 随机FOURIER谱 脉动风速 剪切子区 边界波长 

分 类 号：TU973.32[建筑科学—结构工程]