斜拉桥拉索磁流变阻尼器减振技术的参数优化研究

针对应用磁流变阻尼器控制斜拉桥拉索振动中参数优化这一关键问题,通过试验研究,建立了目前常用的RD-1005型磁流变阻尼器非线性双黏性模型,得到了基于输入电压、激振频率、振动幅值等参数的磁流变阻尼器等效黏性阻尼系数计算公式;然后提出了考虑拉索垂度、弯曲刚度和倾角等因素影响的黏性阻尼器拉索减振设计方法,修正了Pacheco的设计曲线;最后提出了磁流变阻尼器拉索减振的优化设计方法,并通过实桥试验得到验证。     

Friction damper for vibration control in offshore steel jacket platforms

The performance of friction dampers to mitigate the wave-induced vibrations in jacket-type offshore platforms has been investigated in this study. Due to the random nature of ocean waves, a full stochastic analysis method has been used to evaluate the response of the structures equipped with these devices. A stochastic linearization technique has also been used to take the nonlinear behavior of these hysteretic dampers into account. At last, the developed mathematical formulation has been applied to evaluate the response of realistic models, and to find out the optimal values for the adjustable parameters of the friction dampers to dissipate the wave induced vibrations of the platforms.     

A proposed structural design method considering fluid viscous damper degradations

The purpose of this study is to perform a seismic assessment of the moment resistant steel structures enhanced with viscous dampers where the dampers are degraded due to possible leak of viscous fluid. This paper proposes a design procedure based on corrected response spectrums as a result of seismic assessments based on nonlinear time series analyses on three‐, five‐, and seven‐story steel frame structures denoted as “generic structures.” The proposed design procedure is a seismic displacement‐based design methodology for buildings with viscous dampers as passive energy dissipation systems. Prior literature on these types of structures often overlook the viscous dampers degradation due to the fluid leak. In this paper, in order to study these effects, a target displacement is specified at first and the lateral forces and required stiffness are obtained. The effectiveness of the proposed procedure is verified with the collapse fragility curves of the generic structures according to the ASCE 7‐10 and displacement‐based design methodology. The results show that the structures designed based on proposed procedure demonstrate acceptable performance with degrading dampers.     

粘弹性阻尼器参数设计及位置优化实用方法

粘弹性阻尼器是减振被动控制中一种十分有效的耗能减震装置.本文系统地阐述了粘弹性阻尼器用于结构抗震控制的设计方法，根据粘弹性阻尼器的耗能原理友抗震规范方法提出了粘弹性阻尼器位置优化实用方法，比较了粘弹性阻尼器在不同位置布置下的减震效果，并为粘弹性阻尼器几何参数及位置确定提供了实用可行的设计过程。     

Numerical and experimental study of hysteretic behavior of cylindrical friction dampers

Frictional dampers utilize the mechanism of friction for absorbing and dissipating the energy imparted to the dynamic systems. Frictional dampers are widely used in mechanical systems in various industries in order to mitigate the impact and vibration effects. Frictional dampers are also utilized in structures as means of passive control to improve the seismic behavior of structures.In this investigation, an innovative type of frictional damper called cylindrical friction damper (CFD) is proposed. This damper consists of two main parts, the inner shaft and the outer cylinder. Dimensions and properties of the main parts are defined based on seismic demand of structures. These two parts are assembled such that one is shrink fitted inside the other. Upon application of proper axial loading to both ends of the CFD, the shaft will move inside the cylinder by overcoming the friction. This in turn leads to considerable dissipation of mechanical energy. In contrast to other frictional dampers, the CFDs do not use high-strength bolts to induce friction between contact surfaces. This reduces construction costs, simplifies design computations and increases reliability in comparison with other types of frictional dampers.The hysteretic behavior of CFD is studied by experimental and numerical methods. The results show that the proposed damper has great energy absorption by stable hysteretic loops, which significantly improves the performance of structures subjected to earthquake loads. Also, a close agreement between the experimental and numerical results is observed.     

Wind-induced vibration control of Hefei TV tower with fluid viscous damper

The Hefei TV tower is taken as an analytical case to examine the control method with a fluid viscous damper under wind load fluctuation. Firstly, according to the random vibration theory, the effect of fluctuating wind on the tower can be modeled as a 19-dimensional correlated random process, and the wind-induced vibration analysis of the tower subjected to dynamic wind load was further obtained. On the basis of the others’ works, a bi-model dynamic model is proposed. Finally, a dynamic model is proposed to study the wind-induced vibration control analysis using viscous fluid dampers, and the optimal damping coefficient is obtained regarding the wind-induced response of the upper turret as optimization objectives. Analysis results show that the maximum peak response of the tower under dynamic wind load is far beyond the allowable range of the code. The wind-induced responses and the wind vibration input energy of the tower are decreased greatly by using a fluid viscous damper, and the peak acceleration responses of the upper turret is reduced by 43.4%.     

某医技楼减震弹性时程分析

为研究阻尼器在结构中的优化布置及其减震效果,以某5层医技楼为例,将46个消能支撑体系逐层渐变地安装在原结构上,采用弹性时程分析方法对建筑模型进行计算.通过对减震与非减震结构层间位移角、层间剪力及结构底部剪力的对比,对阻尼器典型滞回曲线的分析得出附加的粘滞阻尼器在地震下拥有饱满的滞回曲线,能够充分发挥减震耗能作用.工程主...     

软钢阻尼器在钢框架中减震效果分析

本文通过对未安装阻尼器的纯框架结构和自下而上逐层增设阻尼器的结构进行非线性地震反应分析,考察软钢阻尼器在钢框架结构中的减震效果。计算结果表明,在结构中安装阻尼器具有一定的减震效果,其减震效果大体上随着自下而上增设阻尼器层数的增多而加强,即各层均设有阻尼器时的减震效果最佳。同时也发现,仅在1至5层安装有阻尼器的结构与各层均设有阻尼器的结构相比其减震效果有所减弱,但地震反应没有明显的增大,且各层地震反应比较均匀,也能够获得较为理想的减震效果。     

Mine blast-induced ground motion response reduction using semi-active devices

The aim of this paper is reducing the responses of structures under the mine blast-induced ground motion by using semi-active tools. In other words, the objective of this study is to provide a method to reduce the destructive effects of underground mine-blast excitation. Investigating the behavior of structures under the mine blast excitation is essential because some buildings are subjected to the blast load of mines due to the rapid urbanization in different regions. Also, the importance of studying this excitation, based on the distinctive nature of mine blast-induced underground motion, becomes more apparent. For proper investigation and comparison of responses, a seismic excitation is considered. To reduce the responses of two proposed shear structures, magnetorheological (MR) and orifice dampers are utilized. The optimum location for these dampers is investigated. To generate the optimal force each time step the clipped-optimal algorithm is used based on the input force. The control force can be changed by adjusting the input voltage and magnetic field of dampers. In this research, structural responses based on optimal and maximum voltage are scrutinized. The results indicated that the proposed method is appropriate for reducing the responses of structures under the mine blast-induced ground motion and seismic excitation.     

Distribution of strong earthquake input energy in tall buildings equipped with damped outriggers

The seismic design of optimal damped outrigger structures relies on the assumption that most of the input energy will be absorbed by the dampers, whilst the rest of the structure remains elastic. When subjected to strong earthquakes, nevertheless, the building structure may exhibit plastic hinges before the dampers begin to work. In order to determine to which extent the use of viscously damped outriggers would avoid damage, both the host structure's hysteretic behaviour and the dampers' performance need to be evaluated in parallel. This article provides a parametric study on the factors that influence the distribution of seismic energy in tall buildings equipped with damped outriggers: First, the influence of outrigger's location, damping coefficients, and rigidity ratios core‐to‐outrigger and core‐to‐column in the seismic performance of a 60‐story building with conventional and with damped outriggers is studied. In parallel, nonlinear behaviour of the outrigger with and without viscous dampers is examined under small, moderate, strong, and severe long‐period earthquakes to assess the hysteretic energy distribution through the core and outriggers. The results show that, as the ground motion becomes stronger, viscous dampers effectively reduce the potential of damage in the structure if compared to conventional outriggers. However, the use of dampers cannot entirely prevent damage under critical excitations.     

消能减震支撑体系研究与在高烈度区的工程应用

对高烈度地震区某6层混凝土框架结构办公楼应用由钢支撑和液体粘滞阻尼器组成的消能减震阻尼器支撑体系进行了抗震分析。利用ETABS软件对其在设防烈度8度(0.3g)的地震作用下的地震反应进行了非线性时程分析。计算分析表明,该类消能减震阻尼器支撑有良好的消能减震效果,为类似工程提供了较好的参考。     

地下结构纵向抗震动力可靠度分析

将沉埋隧道地震反应分析的数学模型应用于地下结构随机地震响应分析,阐述了采用动力分析方法求结构体系的脉冲响应函数的原理和方法,采用傅立叶变换原理和随机振动理论,建立了地下结构纵向随机地震响应统计特征的数学表达式。将结构随机地震响应看成是1个泊松过程,建立了采用首次超越破坏理论计算地下结构抗震可靠度的数学公式。以南京长江越江隧道初步设计方案(沉管段)为例,计算了其在高斯平稳随机过程地震动作用下的动力反应均方根值和纵向抗震动力可靠度。为地下结构整体随机地震反应分析及动力可靠度的研究提供了一种分析途径,为以可靠性理论为基础的地下结构抗震概率设计规范的制订奠定了理论基础。     

Seismic performance of MR frames protected by viscous or hysteretic dampers

This study concerns the behaviour of steel frames protected by different anti‐seismic devices (dampers). Typical hysteretic and viscous dampers are arranged in three steel moment‐resisting frames (MRFs) having different dynamical features but are designed to accomplish determined performance objectives. The proposed devices are selected following an iterative procedure based on the use of a suitable damage functional, which has been applied to control the behaviour of the protected structures under a specific seismic record. The outcomes obtained by implementing incremental dynamic analyses, carried out on the basis of seven historical records characterized by different features, allow to analyse the improvement of the structural performance due to the considered dampers and, therefore, to provide design information about their employment. The comparison of results is carried out taking into account the dampers capacity to protect the structures from damage, the inter‐storey drifts, the residual deformations and the possible amplification effects. In conclusion, the equivalent behaviour factors for each damper type are given, with the aim of providing useful design parameters for the implementation of simplified conventional linear analyses. Copyright © 2014 John Wiley & Sons, Ltd.     

黏弹性阻尼器抗震疲劳性能试验加载制度研究

我国现行规范及规程对于黏弹性阻尼器抗震疲劳性能试验要求未能完全真实地反映其性能特点,使得许多性能优良的黏弹性阻尼器不能满足现行标准中的疲劳性能要求,而黏弹性阻尼器由于其黏弹性材料的特殊性,若其未发生破坏,放置一段时间后力学性能会有明显恢复。因此,针对黏弹性阻尼器抗震疲劳性能试验中的加载制度低估了黏弹性阻尼器性能这一问题,提出了一种改进的黏弹性阻尼器抗震疲劳性能试验加载制度,即先在100%应变幅值下预加载5圈以剔除初始刚度的影响,再按照“5圈100%应变幅值加载,20圈50%应变幅值加载,5圈100%应变幅值加载”的加载制度进行30圈加载。通过对比黏弹性阻尼器的滞回耗能,发现黏弹性阻尼器在改进加载制度下的滞回耗能大于绝大部分天然地震动下的滞回耗能,从能量的角度验证了所提改进加载制度的合理性。     

非线性粘滞阻尼器在框架结构抗震加固设计中的应用

本文介绍了非线性粘弹性阻尼器的性能特点及消能减震原理。并以实际抗震加固工程为例对粘滞阻尼器、屈曲约束支撑及传统加固方法的特点进行了对比,并对粘滞阻尼器的设计流程及方法进行了阐述和探讨。     

基于高强钢碟簧和复合摩擦材料的自复位消能减震阻尼器受力性能与试验研究

为提高建筑结构抗震韧性,实现震时响应可控,震后易修复的性能目标,提出一种基于高强钢碟簧和复合摩擦材料的自复位消能减震阻尼器,给出一种基本构造方案,分析阻尼器不同阶段的工作原理,理论推导滞回曲线及各阶段刚度、承载力计算公式。通过多次往复加载试验,对碟簧和摩擦片的基本性能,以及多次地震作用下阻尼器的滞回性能和低周疲劳性能进行了考察。试验结果表明,高强钢碟簧性能稳定,复合摩擦材料耗能能力优异;基于两者组合的自复位消能减震阻尼器具有良好的可调节刚度、承载力以及优异的自复位性能;阻尼器滞回耗能稳定,可实现震后功能恢复,低周疲劳性能好。提出的阻尼器工作过程中各阶段刚度及承载力计算公式与试验结果吻合较好,可为工程设计提供参考。     

Energy-based design optimization of steel building frameworks using nonlinear response history analysis

Presented in this paper is a design optimization method for steel building frameworks subjected to seismic loading using a nonlinear response history analysis procedure. Minimum weight, minimum seismic input energy and maximum hysteretic energy of fuse members are identified as the three design objectives. Design constraints include the limits on inter-story drift and plastic rotation of member sections. The design optimization method employs a multi-objective genetic algorithm to search for optimal member section sizes from among commercially available steel section shapes. The design method is illustrated for a moment-resisting steel frame of a three-story building. It is concluded the proposed optimization methodology is an effective and efficient application of the capacity-design principle to building frameworks under earthquake loading.     

Wind-induced vibration control of Hefei TV tower with fluid viscous damper

The Hefei TV tower is taken as an analytical case to examine the control method with a fluid viscous damper under wind load fluctuation. Firstly, according to the random vibration theory, the effect of fluctuating wind on the tower can be modeled as a 19-dimensional correlated random process, and the wind-induced vibration analysis of the tower subjected to dynamic wind load was further obtained. On the basis of the others’ works, a bimodel dynamic model is proposed. Finally, a dynamic model is proposed to study the wind-induced vibration control analysis using viscous fluid dampers, and the optimal damping coefficient is obtained regarding the wind-induced response of the upper turret as optimization objectives. Analysis results show that the maximum peak response of the tower under dynamic wind load is far beyond the allowable range of the code. The wind-induced responses and the wind vibration input energy of the tower are decreased greatly by using a fluid viscous damper, and the peak acceleration responses of the upper turret is reduced by 43.4%. __________ Translated from Journal of Southeast University (Natural Science Edition), 2008, 37(6): 1018–1022 [译自: 东南大学学报(自然科学版)]     

粘滞流体阻尼器用于建筑结构的减震设计原理与方法

研究了粘滞流体阻尼器用于建筑结构消能减震设计的原理、分析方法。包括阻尼器的设置、消能支撑的型式、支撑钢杆的设计、抗震设防目标、消能减震建筑结构的特点。给出了消能减震结构的附加水平控制力、附加有效阻尼比、地震影响系数、阻尼矩阵的计算方法;介绍了振型分解反应谱法和直接动力时程分析法的设计计算要点。最后给出了采用粘滞流体阻尼器进行消能减震设计的实用设计步骤。     

磁流变阻尼器在结构减震控制中的位置优化研究

高层建筑结构中由于地震引起的振动有时是十分严重的,利用磁流变阻尼器进行振动控制的方法可以有效减小体系的振动反应。这种振动控制的效果,不仅取决于阻尼器出力大小和控制算法的优化,也取决于阻尼器在高层结构中的布置方式。本文首先对近年来出现的各种优化布置方法进行了介绍,然后提出了一种新的基于改进遗传算法和等效二次型性能指标的优化方法,并论述了这些方法的优缺点,最后采用五种优化布置方法并结合一个具体实例进行了磁流变阻尼器的优化布置研究,给出了磁流变阻尼器优化布置的几个原则。