土-结构相互作用阻尼矩阵建模问题研究

Research on modeling of damping matrix about soil structure interaction

首先针对土层采用瑞利阻尼假定时,对2阶频率的选取方法进行了探讨,提出了5种方式,通过土层线性地震反应的数值计算,分析了各自引起的误差;然后针对土-结构相互作用问题进行了计算,比较分析了瑞利及柯西阻尼矩阵形成过程中,频率及阻尼比的最优选取方法。发现采用瑞利阻尼时,如果频率及振型阻尼比选择的适当,精度很高,但如果所采用的频率及阻尼比选择不当,仍会带来较大误差。为便于计算,可采用近似方法对阻尼矩阵进行对角化处理,经验证精度较好。

First, the two order frequency selection method was discussed when using Rayleigh damping assumption of the soil layer. Five ways were put forward, through numerical calculation of the linear seismic response of soil layer, the errors caused by each were analyzed. Then soil-structure interaction problem was calculated and the opti- mal selection method of frequency and damping ratio was compared and analyzed. In the process of forming Rayleigh and Cauchy damping matrices, found that when using Rayleigh damping , if the frequency and mode damping ratio are appropriate, the accuracy is very high. However, if the frequency and damping ratio are chosen improper- ly, it will lead to large errors. In order to facilitate calculation, approximate method is adopted to deal with the damping matrix. It is proven that the accuracy is good.