非平稳地震下巨子型有控结构非线性随机振动研究

Nonlinear random vibration analysis of mega-sub controlled structure subjected to non-stationary seismic excitation

以Priestley演变谱理论对非平稳振动的描述为基础,同时参考了虚拟激励法计算随机振动响应的思路,利用等效线性化方法推导出滞迟系统在强度-频率双非平稳激励下的非线性响应求解公式。运用推导出来的公式计算了巨子型有控结构(MSCSS)在特定震级、震源距双非平稳地震随机激励下的非线性响应,结果表明一般情况下,子结构的非线性程度越高,MSCSS的响应越小,同时表明具有振动控制能力的MSCSS可以较传统的巨型框架结构拥有更好的抗震能力。研究了MSCSS构造参数的设置,如巨子结构质量比、巨子结构相对刚度比在不同非线性程度下对结构减震性能的影响规律,在实际应用中可以根据计算结果合理分配这些参数,以达到最佳减震效果。

According to the Priestley＇s evolutionary spectrum theory and pseudo excitation method, and based on equivalent lin- earization method the formula are derived for calculating nonlinear responses of hysteretic system subjected to non-stationary excitations with amplitude and frequency variations. The nonlinear random responses of Mega-Sub Controlled Structure System （MSCSS） were calculated. Results demonstrate that in the general case the stronger the nonlinearity of the sub-structure the less the response of the MSCSS. The MSCSS is more favorable than traditional mega-frame structure in vibration control. Fur- thermore, the influences of structural parameters, such as the mass ratio and the stiffness ratio between mega-structure and sub-structure, on structural vibration reduction under different nonlinearity degree are investigated, which can be used to opti- mize the vibration control ability.