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利用虚拟激励法和等效线性化技术,通过缩减等效线性化微分方程的数量,提出了求解三维有限元模型基础隔震结构非平稳随机响应的近似计算方法。计算中,假定隔震系统即使在受到大震激励时,其上部结构也依然处于弹性状态,塑性变形主要集中在隔震层处,隔震支座的本构关系采用Bouc-Wen模型描述。根据基础隔震结构响应的特点,假定同种类型支座相同方向滞迟变量大小相等,这样就可以显著减少参与计算的等效线性化微分方程的数量,降低微分方程组的阶数,提高了计算效率和精度。通过分析一简单的三维基础隔震的框架结构,验证了所提方法的正确性。该方法可以考虑不同类型隔震支座的差异性,方便地求得地震作用下各个支座的破坏情况,对于分析隔震支座在地震中的基础提离问题具有重要意义。
By using the virtual excitation method and the equivalent linearization technique, an approximate calculation method for solving the nonstationary random response of the base isolation structure of three-dimensional finite element model is proposed by reducing the number of equivalent linear differential equations. In the calculation, the superstructure is assumed to be in elastic state even when it is excited by large earthquake. The plastic deformation mainly concentrates on the seismic isolation layer. The constitutive relation of the isolated bearing is described by Bouc-Wen model. According to the characteristics of the base isolation structure response, assuming that the same type of hysteresis variables of the same type of support are equal in size, the number of equivalent linear differential equations involved in the calculation can be significantly reduced, the order of the differential equations can be reduced, Calculate efficiency and accuracy. The correctness of the proposed method is verified by analyzing the frame structure of a simple three-dimensional base-isolated structure. The method can consider the difference of different types of isolation bearings and can easily obtain the damage of each support under the action of an earthquake, which is of great significance for analyzing the basic lifting problem of the isolation bearings in an earthquake.