基于结构基频确定Rayleigh阻尼系数的优化方法及其讨论

An Optimization Solution for Rayleigh Damping Coefficients Based on the Fundamental Frequency of Structure

对于一般工程结构而言,低阶振型在结构的动力反应中起主导作用,为此提出一种基于结构基频的直接确定Rayleigh阻尼系数的优化方法,以避免构造Rayleigh阻尼矩阵过程中选择两阶振型的任意性.以地震波反应谱随阻尼比变化的经验公式为基础,形成反应谱导数的近似计算公式,从而得到一个仅需地震波反应谱和结构模态分析结果即可综合考虑结构动力特性、地震波频谱特性的Rayleigh阻尼系数的计算方法.任意选择10条地震波对某自由场进行地震反应分析,通过对不同Rayleigh阻尼系数确定方法的分析比较,验证了所提方法的有效性.

For general engineering structure, dynamic response. In order to avoid an arbitrary ate the two coefficients of Rayleigh damping, a based on the fundamental frequency of structure quake spectrum varying with damping ratio, the the low order modes play a leading role in the structural selection of two reference vibration modes used to evalu-formulation of optimizing Rayleigh damping coefficients was developed. Based on the empirical equation of earth- approximate solution on the derivation of response spec-trum was obtained. Therefore, a formulation which includes the comprehensive effects of structural dy-namic characteristics and frequency content of seismic excitation was addressed. Seismic responses of a free field subjected to 10 earthquake waves were analyzed, different Rayleigh methods were discussed, and the effectiveness of the proposed method was demonstrated.