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粘弹性阻尼结构的性能、分析方法及工程应用 总被引：34，自引：3，他引：31
本文系统地介绍了粘弹性阻尼器和粘弹性阻尼结构的研究与应用情况,主要包括粘弹性阻尼材料的性能特征;粘弹性阻尼器构造,减震原理及力学模型,粘弹性阻尼结构的性能;分析方法与设计方法及工程应用,对粘弹性阻尼结构的适应性,安全性,经济性进行了评述,提出了今后应加强研究的若干问题。 相似文献
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土木工程结构振动控制的研究进展 总被引：21，自引：2，他引：21
综述了近年来土木工程结构振动控制领域的研究进展和发展现状，指出了其发展前景和有待解决的问题，并介绍了主要变刚度阻尼控制系统的工作原理和组成。 相似文献
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阻尼是结构的重要动力特性之一,是结构抗震分析中的重要因素,但出于简单易行的考虑,现行阻尼理论多采用或简化为黏滞阻尼理论。本文对结构振动中的阻尼理论在综合分析的基础上提出了一种新的加速度阻尼模型,经过理论推导、模型振动实验和数据分析,验证了这种阻尼理论的合理性与可行性,弥补了黏滞阻尼理论在物理学解释与实际应用时的不足,并且在一定程度上简化了工程应用中的振型分解法。 相似文献
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颗粒阻尼器是一种减振性能良好的被动控制装置。由于其呈现较强的非线性特征,本文基于将多颗粒等效为单颗粒的原则,采用等效线性化的方法通过四阶龙格库塔迭代计算,获得颗粒阻尼结构体系在随机振动下的均方根响应,继而对其设计参数进行分析。研究结果表明对于给定的颗粒阻尼结构体系,存在最优的自由行程d使结构加速度均方根最小,同时质量比μ的最优取值与自由行程d紧密相关。 相似文献
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本文针对罕遇地震弹塑性静、动力分析方法中结构的阻尼问题进行了一些算例和理论方面的探讨.总结了现有"规范"对于结构阻尼方面的规定;针对实际的高层混凝土和高层钢结构算例,探讨了各性能设计阶段结构等效阻尼比的变化情况,以及弹塑性阻尼对于结构静力推覆分析和能力谱方法计算结果的影响;探讨了不同的阻尼比对于罕遇地震弹性和弹塑性动力时程分析结果的影响;指出了将Rayleigh阻尼自然推广到弹塑性动力时程分析中所存在的问题;本文提出了实时阻尼比概念,通过算例分析表明可以较好地改进罕遇地震弹塑性动力时程分析中的阻尼问题. 相似文献
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Hilbert-Huang变换在密频结构阻尼识别中的应用 总被引：14，自引：3，他引：14
Hilbert—Huang变换是一种新的数据处理方法，由经验模分解(Empirical Mode Decomposition)技术及Hilbert变换两部分组成。本文研究此方法对于密频结构阻尼识别的应用。首先对于两自由度系统模型，说明该方法用于阻尼识别的步骤。进而研究存在频率密集现象的高层建筑的阻尼识别问题。上述结果与理论值及由半功率带宽法的识别值进行了比较，对比显示Hilbert．Huang方法较传统方法具有良好的识别密频结构阻尼的性能，适用于大型结构的系统识别。 相似文献
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两结构高效阻尼控制体系试验研究 总被引：2，自引：0，他引：2
本文通过模拟地震动振动台试验，研究了两个相邻结构模型的地震响应，结构模型采用一种高效阻尼装置(High Efficient Damper for Multi—Structure System即HEDMS)连接。非线性时程分析与振动台试验结果都证明了该阻尼装置能高效发挥软钢阻尼器的耗能能力，从而显著减轻两结构模型的地震响应。同时，研究还指出了进行阻尼装置设计时应该注意的一些问题。 相似文献
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为保护地震作用下历史遗迹帕特农神庙多鼓石柱,提出将破损的石鼓替换为填充颗粒的空鼓,以减轻多鼓石柱动力响应。本文基于PFC3D与FLAC3D软件,实现了离散-有限耦合作用,模拟了附有颗粒阻尼器帕特农神庙多鼓型石柱,研究了颗粒阻尼器对帕特农神庙石柱的减震效果,并分析地震强度、频率、阻尼器位置等因素对减震效果的影响。研究结果表明,将颗粒阻尼器替换破损的空鼓,PFC3D与FLAC3D耦合计算结果与试验结果基本一致,减震效果显著,说明耦合分析方法研究颗粒阻尼器抗震性能具有较高的可靠性;地震强度不同时,分层颗粒阻尼器仍可较好地耗散能量;颗粒阻尼器对结构的减震性能受激励频率的影响显著,频率越高,减震效果越好;颗粒阻尼器布置在古柱中上部减震效果优于布置在古柱下部。 相似文献
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Laboratory resonant column and cyclic triaxial tests are performed to determine the dynamic response (i.e. shear modulus and damping) of chemically grouted sand. The effect of chemical grouting is evaluated as a function of shearing-strain amplitude, confining stress, cycling prestrain, number of cycles, grout type, concentration, and curing time. The test results show that the shearing-strain amplitude, grout type and grout concentration have significant effects on the shear modulus and damping ratio of the test specimens. The increased addition of sodium silicate grout, which produces stiff gels, improved the shear modulus of the test sand. The acrylate (AC-400) and polyurethane (CG5610) grout, which produces flexible (rubber-like) gels, improved the damping capacity of the sand with increasing grout concentration. The addition of chemical grout greatly reduces the effect of cyclic prestraining over untreated sands. In the case of dense sands, the reduction of cyclic prestraining is less pronounced than in loose sands, which have a higher potential for particle movement and reorientation. 相似文献
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Particle dynamics are investigated experimentally in supercritical high‐speed open channel flow over a fixed planar bed of low relative roughness height simulating flows in high‐gradient non‐alluvial mountain streams and hydraulic structures. Non‐dimensional equations were developed for transport mode, particle velocity, hop length and hop height accounting for a wide range of literature data encompassing sub‐ and supercritical flow conditions as well as planar and alluvial bed configurations. Particles were dominantly transported in saltation and particle trajectories on planar beds were rather flat and long compared with alluvial bed data due to (1) increased lift forces by spinning motion, (2) strongly downward directed secondary currents, and (3) a planar flume bed where variation in particle reflection and damping effects were minor. The analysis of particle saltation trajectories revealed that the rising and falling limbs were almost symmetrical contradicting alluvial bed data. Furthermore, no or negligible effect of particle size and shape on particle dynamics were found. Implications of experimental findings for mechanistic saltation‐abrasion models are briefly discussed. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
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A consistent account is given of the theory of resonant interactions between energetic charged particles and a whistler-mode
wave propagating obliquely to the non-uniform geomagnetic field in the inhomogeneous magnetospheric plasma. The basic equations
for the wave field and charged particle dynamics are presented, with the emphasis being placed on the parameters governing
the problem. A Hamiltonian approach is consistently used in the analysis of the particle equations of motion which are discussed
in detail and solved analytically in various cases. Two applications of the theory are considered. First, we calculate the
growth (or damping) rate for a whistler-mode wave propagating obliquely to geomagnetic field in the magnetosphere. Secondly,
we estimate the proton precipitation into the upper atmosphere induced by a VLF transmitter signal. 相似文献
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In this study, attempts are made to investigate the effects of inertial soil–structure interaction (SSI) on damping coefficients subjected to pulse-like near-fault ground motions. To this end, a suit of 91 pulse-like near-fault ground motions is adopted. The soil and superstructure are idealized employing cone model and single-degree-of-freedom (SDOF) oscillator, respectively. The results demonstrate that soil flexibility reduces and amplifies the damping coefficients for structural viscous damping levels higher and lower than 5%, respectively. The coefficients reach one for both acceleration and displacement responses in cases of dominant SSI effects. The effect of structure dimensions on damping confidents are found insignificant. Moreover, damping coefficients of displacement responses are higher than those of acceleration responses for both fixed-base and flexible-base systems. Evaluation of damping correction factor introduced by FEMA 440 shows its inefficiency to predict acceleration response of soil–structure systems under pulse-like near-fault ground motions. Soil flexibility makes the damping correction factor of moderate earthquakes more pronounced and a distinctive peak value is reported for cases with dominant SSI effects. 相似文献
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The damping reduction factors are used in a few building codes in order to estimate the elastic response spectrum with high damping ratios from its 5%‐damped counterpart. At present, much research regarding this factor has been published. The purpose of this paper is to evaluate the accuracy of five different models of damping reduction factors. In addition, the damping reduction factors adopted in the recent U.S.A. seismic codes are also evaluated. Statistical studies are carried out according to a total of 216 earthquake ground motions recorded on firm sites in California. Considered here are elastic single‐degree‐of‐freedom (SDOF) systems with natural vibrating periods between 0.1 and 6.0 s. Mean ratios and dispersion of approximate to exact maximum elastic displacement demands corresponding to various damping reduction factors are computed as functions of the natural vibrating period and the viscous damping ratio. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
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利用有限元软件SAP2000建立了某公路简支梁桥的有限元模型,以7条典型强震记录为输入,研究了公路简支梁桥的地震能量响应及其分配规律。结果表明:①地基柔性效应对公路简支梁桥的地震能量响应及其分配规律的影响较小;②当场地土质变软时,地震总输入能、结构阻尼耗能和结构阻尼耗能比均呈递增趋势,而结构滞回耗能和结构滞回耗能比则不断减小,即地基土体作为桥梁动力系统的一部分,增大了系统阻尼,并分担了部分非弹性变形;③随着PGA增大,输入结构的地震能量也增加,导致塑性铰的非弹性变形增加,即结构滞回耗能和结构阻尼耗能增大。 相似文献
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压电-T型变摩擦阻尼器及其性能试验与分析 总被引：9，自引：0，他引：9
本文结合压电驱动器和T型摩擦阻尼器的特点，提出了压电-T型变摩擦阻尼器，并建立了阻尼器输入电压主动调节或按位移和速度相关调节的阻尼力模型。其次，设计制作了最大阻尼力450N、阻尼力可调倍数2.5～3倍的小比例模型压电-T型变摩擦阻尼器，进行了可调阻尼力性能试验，得到了输入电压主动调节和分别按位移和速度相关调节的阻尼力滞回曲线，试验结果与阻尼力模型分析结果吻合较好。此外，探讨了压电-T型变摩擦阻尼器的规格化设计，分别设计了最大阻尼力20kN和200kN、阻尼力可调倍数2的压电-T型变摩擦阻尼器参数。压电-T型变摩擦阻尼器构造简单、阻尼力调节方便、响应迅速，是一种性能优燎能阻尼器. 相似文献