双塔电压发生器地震反应分析的Rayleigh阻尼矩阵

Damping matrix models in seismic response analysis of twin-tower voltage generators

电压发生器设备因具有长细比大、重心高、阻尼比小等特点,十分不利于抵御水平地震作用或强风作用.为了研究此类结构在地震反应分析中阻尼矩阵的建模问题,以明置于室外地表的某双塔电压发生器为例,分析了结构的动力特性,并计算和讨论了结构在Taft波、El-Centro波和宁河波作用下,采用不同Rayleigh阻尼矩阵建模时的结构动力反应.计算结果表明:不同Rayleigh阻尼矩阵比例系数的选取,对结构的动力反应计算结果的正确性产生很大影响.因此应综合考虑地震波的频谱特性和结构的自振特性选取两阶自振频率,从而使得计算结果更加接近真实解.

The voltage generator equipment is not conductive to resist horizontal seismic actions and strong wind actions for its large slenderness ratio,high center of gravity and low damping ratio. To study the damping matrix models in seismic response analysis of the generator,the dynamic characteristics of a twin-tower voltage generator were analyzed under the excitations of three waves（ Taft wave,El-Centro wave and Ninghe wave）with six different Rayleigh damping modes. The results show that the selection of damping coefficients has great influences on the calculation accuracy of structural dynamic responses. As the damping coefficients are determined by the two natural frequencies of vibration,it is wiser to take both characteristics of seismic spectra and structural natural vibration properties into account when choosing the damping coefficients,so that the calculation results will be more accurate.