Model Based or Data Based Approaches for the Identification of Structural Nonlinearity with Limited Output Measurements

由于自然或人为的因素，非线性广泛的存在于实际结构中，包括为抵抗地震作用在结构基底中设置的橡胶隔震支座的非线性行为，以及建筑结构在长期的损伤累积中所产生的非线性行为。由此可见，非线性的识别研究对于结构的安全评估与损伤诊断起着非常重要的作用。故本文在总结了目前国内外非线性结构识别的研究进展的基础上，研究部分观测结构响应下，结构非线性特性识别的新方法。 论文首先研究基础隔震结构中橡胶隔震支座的非线性特性的识别方法。当隔震支座的非线性特征具有合适的数学物理模型时，采用基于扩展卡尔曼滤波的方法识别出结构的状态向量和非线性参数；当隔震支座的非线性数学模型难以准确建立时，采用基于数据驱动的方法，先在小震作...Due to some natural and man-made factors, nonlinearity widely exists in the actual structure, including that the nonlinear behavior of rubber-bearing setting to resist seismic action in base-isolated building, and the nonlinear behavior of the structure because of the damage development in the long-term. Thus, the research on the identification of structural nonlinearity plays a very important rol...学位：工学硕士院系专业：建筑与土木工程学院_结构工程学号：2532011115172

Model-free identification for nonlinear properties of rubber-bearings in base-isolated buildings

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.国家自然科学基金课题(51178406); 同济大学土木工程防灾国家重点实验室开放课题(SLDRCE10-MB-01)资

膜技术处理赖氨酸生产废水的研究

为了确定赖氨酸生产废水经过膜技术处理后废水中的CODcr值的大小 ,我们采用超滤与纳滤相结合的工艺分别对浓废水和稀废水进行中试实验。实验结果表明 :采用超滤 -一级纳滤 -二级纳滤工艺流程处理浓废水 ,终端废水的CODcr值降低到 489mg/L ;采用超滤 -纳滤流程处理稀废水 ,最终透析液的CODcr值可以降低到 5 0 2mg/L。大大减轻了后续生化处理的负荷

Identification Method for Shear Building Under Unknown Seismic Excitation with Experimental Validation

针对框架结构的绝对加速度响应部分观测、地震作用未观测的情况,提出一种多层剪切框架结构诊断的方法.该方法先依次采用扩展卡尔曼估计和递推最小二乘法对1层以上结构的扩展状态向量和未知作用力进行递推;然后利用结构频率特征方程,对第1层的结构参数进行估计;最后基于数值求解一阶微分方程,识别未观测的地震作用.通过1个4层框架试验,表明该方法能够很好地识别出结构参数和地震输入.A method is proposed for the identification of multi-story shear buildings under unknown seismic excitation with partial observations of structural absolute acceleration responses.Based on sequential application of the extended Kalman estimator and the least squares estimation,structural parameters above the first story of a building can be identified.Then,structural parameters of the first story can be identified from the frequency equation.Finally,the unknown earthquake excitation can be identified via the numerical solution of a first-order differential equation.Lab experiments of a 4-story shear building on a shaking table test have validated that the proposed method can determine structural parameters and the earthquake excitation with satisfactory accuracy.国家自然科学基金(51178406