附加或不附加粘滞阻尼墙的RC框架试验与分析

本文阐述了附加或不附加粘滞阻尼墙的2个相同的RC框架模型振动台试验和理论分析的情况.这2个钢筋混凝土框架模型为3层1跨两开间,几何相似关系大致为1：2.将阻尼墙附加到一个RC框架模型当中,先后对附加或不附加阻尼墙的2个相同的RC框架模型进行振动台试验.试验结果表明,阻尼墙有效减小了框架模型的地震反应.对耗能框架模型和普通框架模型进行了弹性和弹塑性时程分析,计算结果和试验结果吻合良好.改变阻尼墙的参数进行分析,结果表明选取合适的阻尼墙参数,才能达到最好的耗能减振效果;适当减小层间位移较小处的阻尼墙参数,对减振效果影响很小而又能节省投资.     

结构阻尼与材料阻尼的关系

针对固体材料在弹性阶段的内阻尼,采用材料粘弹性本构关系,通过有限单元法建立了考虑剪切变形影响的杆单元阻尼矩阵,得到了材料拉压粘滞系数和剪切粘滞系数之间的关系。我们可以通过实验测试材料的损耗因子或粘滞阻尼系数(材料阻尼),像结构质量矩阵、刚度矩阵一样通过比较确切的计算得到弹性阶段结构内阻尼的阻尼矩阵(结构阻尼),而且此阻尼矩阵既基于材料阻尼实验测试,又便于数学处理,且物理意义明确。其次,本文分析了材料阻尼对结构阻尼比影响,得到了材料损耗因子与结构模态阻尼比间的关系,并通过10层钢筋混凝土剪切型框架结构进一步给出了具体的数值结果。     

网壳结构的粘滞阻尼减振分析与试验研究

本文将粘滞阻尼器引入网壳结构,针对网壳结构粘滞阻尼器减振系统,编制了有限元分析程序,并对网壳结构进行了大量的振动控制分析和计算。作者设计制做了适合网壳结构的粘滞阻尼器,进行了性能试验;在此基础上设计制作了一个球型网壳结构模型,并进行了粘滞阻尼器减振的地震模拟振动台试验。     

粘滞阻尼器力学性能试验研究

叙述了粘滞流体阻尼器用于结构消能减震的优点，把根据某一抗震加固工程需要而设计的一种国产粘滞流体阻尼器放在伪静力装置下试验其力学特性，试验结果表明其耗能效果良好，同时了解了其本身的有限刚度特性，提出了粘滞流体阻尼器支撑系统刚度设计的要求。     

粘滞阻尼耗能连梁的超高层结构减震性能研究

连梁作为剪力墙结构中的抗震第一道防线,其承载力和耗能能力对整体结构的抗震性能有重要影响。本文提出在连梁中附设粘滞阻尼器,利用阻尼器发生竖向剪切变形而耗能。结合实际工程研究粘滞阻尼耗能连梁的性能,采用ETABS和PERFORM-3D软件对粘滞阻尼耗能连梁结构与传统连梁结构进行有限元模拟对比分析,并对粘滞阻尼耗能连梁的各项最优参数进行研究。结果表明:粘滞阻尼耗能连梁充分发挥耗能作用,整体结构具有良好的抗震性能,与传统连梁结构相比,主体结构的弹性耗能得到明显降低。平面布置方式、竖向布置方式、阻尼器参数的选取对附设粘滞阻尼耗能连梁的框架-核心筒结构减震效果影响较大,合理选择这些参数可以使耗能结构减震效果最优。     

三种阻尼减振结构抗震性能的对比分析

对设置两种新型摩擦阻尼器(T形芯板摩擦阻尼器和拟粘滞摩擦阻尼器)和粘滞阻尼器的单自由度结构及多层实际工程结构进行了时程分析研究。结果表明，一方面三种阻尼器都能有效地控制结构的反应，另一方面T形芯板摩擦阻尼器的位移控制效果略好于拟粘滞摩擦阻尼器，但是后者的加速度控制效果好于前者。     

基于能量原理的粘滞阻尼器附加阻尼系数分配方法研究

以线性粘滞阻尼器加固剪切型规则框架结构为研究对象,基于能量原理提出附加阻尼系数正比于层间位移平方的分配方式。以六层和十二层钢筋混凝土框架为例,以确保结构在中震时保持弹性状态为设计目标,分别采用附加阻尼系数正比于层间位移平方的分配方式以及现有的分配方式,对结构进行消能减震设计。计算结果表明:有控结构均满足中震不坏的要求,层间位移角限值均未超过1/550,减震效果良好;附加阻尼系数正比于层间位移平方的分配方式得出的总阻尼系数最小,为最经济的设计结果。     

替换阻尼杆件的双层柱面网壳被动控制振动台试验研究

本文在拟动力装置上对自行设计的孔隙式粘滞阻尼杆件进行了性能测试，并用其替换双层柱面网壳的部分下弦杆进行了被动减震控制的振动台试验，输人了多种能级的不同地震动，针对替换不同位置和数量的阻尼杆件进行了多种工况下的试验研究。试验结果表明减震效果明显，与理论分析结果吻合较好。     

一种新型SMA阻尼器的试验研究

在对NiTi形状记忆合金（SMA）的力学性能试验研究的基础上,设计了一种新型SMA阻尼器,根据形状记忆合金丝的超弹性分段线性恢复力模型建立了阻尼器的理论模型,并通过阻尼器的性能试验研究验证了理论模型的正确性,试验结果表明这种阻尼器具有较好的耗能能力。     

油缸间隙式粘滞阻尼器理论与性能试验

本文首先研究了双出杆油缸间隙式粘滞阻尼器的构造,讨论了不同类型粘滞流体的特性;;然后,在幂律流体本构关系的基础上,建立了粘滞阻尼器的阻尼力计算模型;;最后,设计制作了两个粘滞阻尼器,进行了详细的性能试验,通过试验结果的统计分析,得到了阻尼力计算模型的幂指数。     

黏性阻尼与复阻尼对钢筋混凝土框架结构地震响应影响的分析

本文讨论了利用黏性阻尼和复阻尼模型求解结构动力响应的方法;按相同的阻尼比,分别采用复阻尼模型和黏性阻尼模型计算了两个框架结构在不同地震波作用下的响应,并将结果进行对比,分析了两种不同的阻尼模型对结构动力响应的影响。结果表明,采用不同类型的阻尼对结构响应影响很大。     

Experimental analysis on the impact force of viscous debris flow

A miniaturized flume experiment was carried out to measure impact forces of viscous debris flow. The flow depth (7.2–11.2 cm), velocity (2.4–5.2 m/s) and impact force were recorded during the experiment. The impact process of debris flow can be divided into three phases by analyzing the variation of impact signals and flow regime. The three phases are the sudden strong impact of the debris flow head, continuous dynamic pressure of the body and slight static pressure of the tail. The variation of impact process is consistent with the change in the flow regime. The head has strong–rapid impact pressure, which is shown as a turbulent‐type flow; the body approximates to steady laminar flow. Accordingly, the process of debris flows hitting structures was simplified to a triangle shape, ignoring the pressure of the tail. In order to study the distribution of the debris flow impact force at different depths and variation of the impact process over time, the impact signals of slurry and coarse particles were separated from the original signals using wavelet analysis. The slurry's dynamic pressure signal appears to be a smooth curve, and the peak pressure is 12–34 kPa when the debris flow head hits the sensors, which is about 1.54 ± 0.36 times the continuous dynamic pressure of the debris flow body. The limit of application of the empirical parameter α in the hydraulic formula was also noted. We introduced the power function relationship of α and the Froude number of debris flows, and proposed a universal model for calculating dynamic pressure. The impact pressure of large particles has the characteristic of randomness. The mean frequency of large particles impacting the sensor is 210 ± 50–287 ± 29 times per second, and it is 336 ± 114–490 ± 69 times per second for the debris flow head, which is greater than that in the debris flow body. Peak impact pressure of particles at different flow depths is 40–160 kPa, which is 3.2 ± 1.5 times the impact pressure of the slurry at the bottom of the flow, 3.1 ± 0.9 times the flow in the middle, and 3.3 ± 0.9 times the flow at the surface. The differences in impact frequency indicate that most of the large particles concentrate in the debris flow head, and the number of particles in the debris flow head increases with height. This research supports the study of solid–liquid two phase flow mechanisms, and helps engineering design and risk assessment in debris flow prone areas. Copyright © 2015 John Wiley & Sons, Ltd.     

新型舌板黏滞阻尼器力学性能试验研究

本文提出了一种新型舌板黏滞阻尼器,通过对该黏滞阻尼器进行低周循环加载试验和抗低周疲劳性能试验,研究并验证了该阻尼器的耗能性能、抗低周疲劳性能及恢复力模型。研究结果表明:选取合适参数的舌板式黏滞阻尼器滞回曲线饱满,耗能性能与抗低周疲劳性能良好。Maxwell模型能够较好地描述该阻尼器力学行为,反映阻尼器在各种试验工况下的出力情况。该阻尼器设计与加工简单,对工程结构的耗能减震有着实际意义。     

Active viscous damping system with amplifying braces for control of MDOF structures

The development and the applications of an active controlled viscous damping device with amplifying braces are described. The system of the dampers, defined as active viscous damping system (AVDS), connected to an amplifying brace (AB) is presented herein. Instantaneous control theory with velocity and acceleration feedback is used to obtain the control forces at each time step during an excitation. Control of the damping forces is possible due to the mechanical structure of the proposed AVDS, and the connection to the AB. The proposed system can be efficiently used to enhance the damping of a structure without modifying its stiffness. The added damping forces can be adjusted in a wide range. The efficiency of the presented system is demonstrated by a numerical simulation of a seven‐storey building subjected to earthquakes. The simulation shows a considerable reduction of control forces required for control to the AVDS with AB, compared to the same system without AB. Copyright © 2002 John Wiley & Sons, Ltd.     

Loss of energy dissipation capacity from the deadzone in linear and nonlinear viscous damping devices

In a viscous damping device under cyclic loading, after the piston reaches a peak stroke, the reserve movement that follows may sometimes experience a short period of delayed or significantly reduced device force output. A similar delay or reduced device force output may also occur at the damper’s initial stroke as it moves away from its neutral position. This phenomenon is referred to as the effect of “deadzone”. The deadzone can cause a loss of energy dissipation capacity and less efficient vibration control. It is prominent in small amplitude vibrations. Although there are many potential causes of deadzone such as environmental factors, construction, material aging, and manufacture quality, in this paper, its general effect in linear and nonlinear viscous damping devices is analyzed. Based on classical dynamics and damping theory, a simple model is developed to capture the effect of deadzone in terms of the loss of energy dissipation capacity. The model provides several methods to estimate the loss of energy dissipation within the deadzone in linear and sublinear viscous fluid dampers. An empirical equation of loss of energy dissipation capacity versus deadzone size is formulated, and the equivalent reduction of effective damping in SDOF systems has been obtained. A laboratory experimental evaluation is carried out to verify the effect of deadzone and its numerical approximation. Based on the analysis, a modification is suggested to the corresponding formulas in FEMA 356 for calculation of equivalent damping if a deadzone is to be considered.     

Effect of viscous damping devices on the response of seismically isolated structures

Viscous and other damping devices are often used as elements of seismic isolation systems. Despite the widespread application of nonlinear viscous systems particularly in Japan (with fewer applications in the USA and Taiwan), the application of viscous damping devices in isolation systems in the USA progressed intentionally toward the use of supplementary linear viscous devices due to the advantages offered by these devices. This paper presents experimental results on the behavior of seismically isolated structures with low damping elastomeric (LDE) and single friction pendulum (SFP) bearings with and without linear and nonlinear viscous dampers. The isolation systems are tested within a six‐story structure configured as moment frame and then again as braced frame. Emphasis is placed both on the acquisition of data related to the structural system (drifts, story shear forces, and isolator displacements) and on non‐structural systems (floor accelerations, floor spectral accelerations, and floor velocities). Moreover, the accuracy of analytical prediction of response is investigated based on the results of a total of 227 experiments, using 14 historic ground motions of far‐fault and near‐fault characteristics, on flexible moment frame and stiff braced frame structures isolated with LDE or SFP bearings and linear or nonlinear viscous dampers. It is concluded that when damping is needed to reduce displacement demands in the isolation system, linear viscous damping results in the least detrimental effect on the isolated structure. Moreover, the study concludes that the analytical prediction of peak floor accelerations and floor response spectra may contain errors that need to be considered when designing secondary systems. Copyright © 2014 John Wiley & Sons, Ltd.     

大吨位双出杆粘滞阻尼器开发的数值模拟与实验研究

阐述了大吨位双出杆粘滞阻尼器开发的数值与实验研究结果.基于硅油的幂律特性,通过对硅油介质的流态分析,介绍了非牛顿幂律流体模型对粘滞阻尼器耗能和阻尼出力的影响,与粘滞阻尼器的分析模型和计算公式.在商用流体软件平台上利用动网格技术对样品粘滞阻尼器阻尼出力进行了计算;综合实验研究结果,最终确定了大吨位土木用粘滞阻尼器设计的经验方法.另一方面,实验曲线和数值曲线基本吻和,验证了通过数值手段对粘滞阻尼器的出力特性进行预分析,从而提高开发精度、指导产品设计和缩短产品的开发周期的可行性.     

Effects of supplemental viscous damping on inelastic seismic response of asymmetric systems

This paper investigates the effects of supplemental viscous damping on the seismic response of one‐storey, asymmetric‐plan systems responding in the inelastic range of behaviour. It was found that addition of the supplemental damping reduces not only deformation demand but also ductility and hysteretic energy dissipation demands on lateral load resisting elements during earthquake loading. However, the level of reduction strongly depends on the plan‐wise distribution of supplemental damping. Nearly optimal reduction in demands on the outermost flexible‐side element, an element generally considered to be the most critical element, was realized when damping was distributed unevenly in the system plan such that the damping eccentricity was equal in magnitude but opposite in algebraic sign to the structural eccentricity of the system. These results are similar to those noted previously for linear elastic systems, indicating that supplemental damping is also effective for systems expected to respond in the inelastic range. Copyright © 2001 John Wiley & Sons, Ltd.