【作者】 曲激婷；

【导师】 李宏男；

【作者基本信息】 大连理工大学 ， 防灾、减灾工程及防护工程， 2008， 博士

【摘要】 由于消能减震结构具有减震机理明确、减震效果显著且安全可靠等优点,易于在工程中推广应用,因此,三十多年来,国内外学者对各种消能装置的试验、理论分析和控制设计方法进行了大量研究,并取得了诸多成果,消能减震技术在新建工程和震损建筑减震、加固中的应用形式和范围也越趋广泛。目前,我国《建筑抗震设计规范》(GB50011—2001)中已经增加了有关消能减震的内容,位移型和速度型两类被动阻尼器是其中需要重点研究和推广的技术。对于形式多样、要求各异的工程结构,如何在推广应用消能技术时,选择适合的阻尼器类型并进行阻尼器的合理优化设计将关系到这一技术的发展前景,具有重要的现实意义,值得进一步探讨研究。在此背景下,本文主要进行了以下几个方面的工作:(1)从时程分析的主体—结构着手,提出根据不同结构模型进行阻尼器选型的方法。鉴于层弯剪型模型在弹塑性分析中存在的问题,对刚度矩阵的修正进行了合理地近似处理。根据动力等效准则设计了与层弯剪型模型第一频率和振型相同且各层质量也相同的剪切型结构,编制了不同计算模型结构的弹塑性时程分析程序;在为结构提供相同附加阻尼比的前提下,对弯剪型和剪切型两种不同形式结构在位移型和速度型阻尼器控制下的非线性地震反应分别进行分析比较。数值分析结果表明,对于不同模型的结构,达到相同抗震性能目标下所需位移型阻尼器和速度型阻尼器的数量不同,且两种类型被动阻尼器的减震效果也不同,建议在进行消能减震技术应用时,可以根据确定的结构分析模型形式以及结构空间状况选用适当类型的被动阻尼器进行振动控制,给出可供工程参考的初步结论。(2)提出一种新型的阻尼器位置优化目标函数,可以综合考虑结构安全性和舒适度的要求。在阻尼器数量一定的前提下,利用遗传算法对位移型阻尼器进行位置优化,并对目标函数中不同的加权系数组合进行了初步探讨。在四类不同场地条件下,对低、中、高层三种不同结构进行阻尼器位置优化,并对阻尼器最优布置下的结构时程反应进行分析对比。数值分析表明,根据新型优化函数得到的阻尼器优化布置可以有效地控制结构反应;通过比较不同加权系数组合情况下的阻尼器最优布置方案,给出有关位移型阻尼器优化布置方面的几点建议以供设计、应用参考。(3)提出了阻尼器位置优化的两个评价指标。在阻尼器数量一定的前提下,以遗传算法为手段,利用新型位置优化目标函数,在四类场地条件下,对短、中、长周期三种结构分别进行了位移型和速度型阻尼器的位置优化。对两种类型阻尼器最优布置下的结构非线性地震反应进行数值分析,以本文提出的两个评价指标为性能指标,将不同消能结构的振动控制效果进行量化比较。数值分析表明,不同类型阻尼器在不同结构和场地条件下进行位置优化时,目标函数中的最优系数组合取值各有特点,为工程应用中针对不同类型阻尼器选取适当形式的优化目标函数提供了一定的参考。(4)将基于位移的抗震设计方法应用于新建或震损建筑减震、加固中阻尼器的设计。针对根据已有多自由度体系目标位移公式计算高层、超高层结构的不合理性,提出了一种修正的结构目标位移计算公式,建立了目标位移和结构性能指标之间的关系。以一定设防等级下结构控制部位的目标位移作为已知条件,而将消能减震装置作为未知条件,根据两种类型阻尼器的等效刚度和等效阻尼比公式,通过等效单自由度体系的逆向计算,进行满足相同结构预期性能目标下的不同类型阻尼器参数设计。以一高层钢结构建筑为例的数值分析表明,采用此方法设计的阻尼器能够满足结构预期的性能目标,设计方法比较简便实用。(5)结合国际上通用的结构振动控制性能评价平台—Benchmark三种结构模型,利用非线性结构振动控制Benchmark评价性能指标,对位移和速度型被动阻尼器的控制效果进行比较分析。将被动控制结构分析同现代控制理论相结合,利用MATLAB/SIMULINK建立了基于位移型和速度型阻尼器的结构仿真模型,分别计算了三种结构模型在近场和远场地震动作用下,不同类型阻尼器对结构反应不同指标的控制效果,为消能结构设计中阻尼器的选用提供了一定的参考。更多还原

【Abstract】 Passive energy dissipation structures have advantages of definite damping mechanism, effective reduction of structural response, safety and reliability. So over thirty years, studies on experiments, theoretical analyses and design methods of various energy dissipation devices have made great development. The technique of passive energy dissipation has been widely applied in seismic control of new constructions and reinforcement of seismic damage structures and has extensive forms. At present, contents related to passive energy dissipation have been written into the China Seismic Code (GB50011-2001). Among it, the use of displacement-based dampers and velocity-based dampers is the technology needed to be emphasized and popularized. But for a variety of forms and different requirement of the projects, how to choose suitable type of dampers and design dampers optimally will affect the development of the technology during its popularization, which has important realistic meaning and is worth of further study. The thesis focuses on seismic behavior comparison and optimal design of different dampers, and the following aspects are devoted to the main effects:(1) Considering different computation models, comparison of the nonlinear vibration control of high-rise structures with additional two type passive dampers is done. For the current problem of storey shear-bending model in elasto-plastic analysis, approximate treatment is done to the stiffness matrix. Designing storey shearing model structure from shear-bending model structure according to dynamically equivalent standard, time-history analysis programs of structures are compiled. On the premise that the equivalent damping of two kind dampers is equal, studies focus on the effect of type and quantity of dampers on structure control effectiveness of different computation models and comparisons are done. The numerical analysis results show that the two types of dampers’ control effectiveness are different for the high-rise structure of different computation models. Suggestions are proposed that when using passive energy dissipation technology, different type of passive dampers should be chosen to control vibration responses according to the structure analysis model.(2) A new objective function of dampers’ location optimization is proposed. As the China Codes have given certain limit to the structure’s drift angle, maximum acceleration and maximum horizontal displacement of vertical components, three structure indexes are comprehensively considered in the new objective function. Various coefficient combinations of indexes can be chosen according to the different requirement of structural security and coziness. On the premise that the number of dampers is fixed, it is dealt with the optimal placement of displacement-based dampers for several building models with different number of stores and seismic ground motions at four types of sites using genetic algorithm. Five kinds of combination modes of the three indices in optimal function are then supposed. Nonlinear step-by-step time history analyses are carried out to achieve the optimal combination mode of the coefficients in mathematic model and the optimal locations of these dampers for several building structures. The optimal results can also verify effectiveness and feasibility of the new objective function for structural control and some meaningful suggestions about optimal placement of displacement-based dampers are given.(3) Two estimating indices are presented to assess the structural responses with different optimal placement of dampers. Using the new objective function, the optimal locations of two types of dampers are analyzed for several building models with different number of stores and seismic ground motions at four types of sites. Two estimating indices are utilized to assess the response to the optimal location under the condition of five combination modes, which can generally express the best response control and the propositional combination of the coefficients is available under different conditions. Comparison of two kinds dampers’ optimal results show that the objective function of location optimization are different for different structures with different dampers and some conclusions for application are given.(4) The displacement-based seismic design method has been applied to the dampers design utilized in new constructions and reinforcement of seismic damage structures. Because of the inconsequence of target displacement formula of multiple-degree of freedom system used for high-rise structures, a modified displacement formula is suggested, which can establish the relationship between the target displacement and the performance indexes. Taking a target displacement of a certain security grading structure as the known condition, and the energy dissipation devices as unknown conditions, according to the equivalent stiffness and damping formulas, the reverse calculation of the equivalent single degree of freedom system was done to gain the design parameters of different types of dampers expected to meet performance targets. The numerical analysis of a high-rise steel structure as an example shows that using this method to design dampers can meet the prospective performance targets, and it is a simple and practical design means.(5) With the international common performance evaluation platform of structural vibration control—the third stage of Benchmark three models, using Benchmark performance evaluation indices of nonlinear vibration control, the control results for displacement-based and velocity-based dampers were compared. Combining the passive control of structures with the modern control theory, using MATLAB/SIMULINK to establish simulation models of the structures with displacement-based and velocity-based dampers, the responses of three Benchmark structure models were calculated under far and near-field earthquakes. Control effectiveness is compared for different types of dampers on different structures through different evaluation indices, which can provide a certain criterion of reference for the application and design of the passive energy dissipation dampers.更多还原