调谐惯容电磁阻尼—摩擦摆组合隔震体系的需求导向设计方法研究

DEMAND-ORIENTED DESIGN METHOD OF THE HYBRID-ISOLATED BUILDING EQUIPPED WITH TUNED INERTIA ELECTROMAGNETIC DAMPER AND FRICTION PENDULUM BEARING

  • 摘要: 为解决强震下摩擦摆基础隔震结构中隔震层位移需求过大的问题,提出一种调谐惯容电磁阻尼—摩擦摆组合隔震体系(TIED-FPB)。考虑FPB和电磁阻尼的非线性特征,将FPB隔震结构简化为两自由度体系,建立该组合隔震体系的运动方程。借助FPB和电磁阻尼的随机等效线性化模型构建等效TID-2DOF体系。基于白噪声激励下隔震层位移的H2范数推导等效TID设计频率比和阻尼比的闭合解。结合复振型分析、复完全平方组合(CCQC)和随机振动分析求解等效TID组合隔震体系在功率谱密度激励下隔震层位移和阻尼相对速度的最大值。给定隔震层位移需求目标,通过迭代更新策略得到等效TID的设计质量比。由TID中线性黏滞阻尼的相对速度最大值和阻尼系数确定TIED中电磁阻尼的特征速度及特征阻尼系数,进而实现TIED的需求导向设计。为验证所提方法的合理性和TIED-FPB组合隔震体系的抗震性能,在OpenSees中构建电磁阻尼材料模型,根据规范设计谱选择44条地震动对一7层隔震Benchmark模型进行非线性时程分析。结果表明:TIED-FPB组合隔震体系的隔震层变形控制效果和加速度响应的鲁棒性均优于FPB隔震结构。

     

    Abstract: To address the risk of the excessive displacement demand of the isolation layer in the friction pendulum bearing (FPB) based an isolation system subjected to severe earthquake excitation, a hybrid isolation system with the tuned inertia electromagnetic damper and FPB (TIED-FPB) is proposed. Considering the mechanical nonlinearity in FPB and electromagnetic damping, the governing equation of the TIED-FPB system is constructed by simplifying the base-isolated structure into a two-degree-of-freedom (two-DOFs) system. By virtue of the stochastic equivalent linearization model of FPB and electromagnetic damping, the equivalent tuned inerter damper (TID)-two-DOFs system is constructed. The closed formula for the design frequency ratio and damping ratio of the equivalent TID is derived by considering the H2-norm of the basement displacement response under the white noise excitation. In the combination with the complex mode analysis, complex complete quadratic combination (CCQC), and stochastic vibration analysis, the maximum responses of the basement displacement and the relative velocity of linear viscous damping in TID are approximated when the isolation system subjected to the power spectrum density excitation. Given the displacement demand target of the isolation layer, the mass ratio of the TID is obtained through the iterative update strategy. The critical velocity and critical damping coefficient of electromagnetic damping in TIED are determined from the maximum relative velocity and the equivalent damping ratio of the damping in TID, further realizing the demand-oriented design of the TIED. To verify the feasibility of the optimization method proposed and the seismic performance of the TIED-FPB isolation system, a new uniaxial material for mimicking the electromagnetic damping was added in OpenSees software, and 44 seismic ground motions were selected according to the standard design spectrum to perform the nonlinear time history analysis of a 7-storey seismic isolation benchmark model. The time history results illustrate that the TIED-FPB system is superior to the FPB-based BI system in terms of the mitigation of the isolator deformation and the robustness of the acceleration response.

     

/

返回文章
返回