结构中基底橡胶隔震支座非线性特性的无模型识别

Abstract

基底隔震建筑结构的抗震性能高度依赖于橡胶支座隔震系统的非线性特性。提出一种基于数据的方法,仅利用量测现役结构的部分加速度动力响应和作用在结构基底的激励,在不需要橡胶支座隔震系统数学模型的情况下,识别出橡胶支座隔震系统的非线性特性。首先,在微弱基底激励作用下,基于扩展卡尔曼预测估计算法识别出结构的物理参数,包括橡胶支座的线性刚度和阻尼。然后,在强基底激励作用下,将橡胶支座出现的非线性视为作用于结构的“附加未知虚拟外力“,通过依次对结构响应进行卡尔曼预测估计和对“附加未知虚拟外力“的最小二乘识别,可以识别橡胶支座的非线性力。数值算例结果表明,提出的方法可以识别出橡胶支座的非线性特性,并具有良好的精度。

Aseismic behavior of base-isolated structures is highly dependent on nonlinear properties of their rubberbearing isolated system.Here,a data-based method using only partial measurements of structural dynamic response and excitation was proposed to identify the nonlinear property of the rubber-bearing isolated system without its mathematical model.Firstly,structural parameters including the linear stiffness and damping of the rubber-bearing under a minor earthquake were identified based on the extended Kalman estimator approach.Then,the nonlinear effect of the rubberbearing was treated as an additional unknown fictitious loading exerted on the building under a severe earthquake.With sequential application of Kalman estimator method in the structural responses and the least-square estimation of the additional unknown fictitious loading,the nonlinear property of the rubber-bearing was identified.Numerical simulation results demonstrated that the proposed method is capable of identifying nonlinear property of a rubber-bearing isolated system with good accuracy.