共查询到20条相似文献，搜索用时 31 毫秒
1.
大跨度球面网壳结构应用日趋广泛,其结构特点使风荷载常常起主要甚至是控制作用,风振动力响应研究日益受到关注与重视。本文讨论了网壳结构风振响应时程分析计算方法,并采用节点位移风振系数来衡量网壳结构风振特性。对角锥型双层球面网壳结构进行了不同几何参数即跨度、矢高、球壳厚度等多种情况下的位移风振系数的研究,得出该类网壳的风振系数随几何参数的变化规律,并回归出计算公式,为双层球面网壳结构的抗风设计提供参考。 相似文献
2.
组合网壳屋盖结构风振响应分析及等效静风荷载 总被引：1，自引：0，他引：1
结合惠州会议展览中心风洞试验结果,对波浪形组合网壳结构的风荷载和风振响应进行了分析,包括：24个风向角下屋盖荷载分布特性分析;结构整体和局部的自振特性分析;根据风洞试验结果对6个风向角（0°、30°、45°、90°、135°和180°）进行结构的风致动力响应分析。根据风振响应分析结果,基于响应的不同振动特点,提出将屋盖结构分为独立屋盖结构、屋盖结构两端挑棚结构和整体屋盖结构3个部分,指出对这3部分最不利的风向角分别为0°、30°、90°。最后综合考虑各个风向角下结构的响应及风振系数,给出了最终的风振系数建议值。 相似文献
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This paper considers the active vibration control of cables and cable/structure systems with an active tendon controlling the axial displacement of the cable anchor point. It is demonstrated that a force feedback based on a collocated force sensor measuring the tension in the cable is feasible and that this control configuration can be associated with control laws with guaranteed stability properties. Experimental results are presented on a cable with small sag and on a cable/structure system. They show that the control algorithm can provide the structure with several percent of active damping and that the parametric resonance does not occur when the natural frequency of the structure is twice that of the cable. 相似文献
5.
《Soil Dynamics and Earthquake Engineering》2012,33(1):71-86
Cable net facades are widely used as a new kind of glazing system and have many advantages, such as pleasing esthetics and easy constructability. With the characteristics of low stiffness, light weight, and small damping, cable net facades are obviously geometrically nonlinear, and the response spectrum method may have some limitations in the seismic design of cable net façades. Therefore, the nonlinear vibration differential equation and natural frequency of the cable net subject to earthquakes was deduced, and then the geometrically nonlinear single-degree of freedom model was founded. Second, with the geometrically nonlinear single-degree of freedom model, the nonlinear seismic response of the cable net was calculated with the time history method subject to four groups of site conditions, and the nonlinear response spectra were founded. Third, the linear and nonlinear acceleration and displacement spectra were compared thoroughly. Lastly, shaking table tests were conducted to verify the accuracy of the nonlinear response spectra. 相似文献
6.
For super high-rise buildings,the vibration period of the basic mode is several seconds,and it is very close to the period of the fluctuating wind.The damping of super high-rise buildings is low,so super high-rise buildings are very sensitive to fluctuating wind.The wind load is one of the key loads in the design of super high-rise buildings.It is known that only the basic mode is needed in the wind-response analysis of tall buildings.However,for super high-rise buildings,especially for the acceleration response,because of the frequency amplification of the high modes,the high modes and the mode coupling may need to be considered.Three typical super high-rise projects with the SMPSS in wind tunnel tests and the random vibration theory method were used to analyze the effect of high modes on the wind-induced response.The conclusions can be drawn as follows.First,for the displacement response,the basic mode is dominant,and the high modes can be neglected.Second,for the acceleration response,the high modes and the mode coupling should be considered.Lastly,the strain energy of modes can only give the vibration energy distribution of the high-rise building,and it cannot describe the local wind-induced vibration of high-rise buildings,especially for the top acceleration response. 相似文献
7.
Major damage has been reported in hilly areas after major earthquakes,primarily because of two special conditions:the variation in the seismic ground motion due to the inclined ground surface and the irregularities caused by a stepped base level in the structure.The aim of this study is to evaluate possible differences in the responses of Chilean hillside buildings through numerical linear-elastic and nonlinear analyses.In the first step,a set of response-spectrum analyses were performed on four simplified 2D structures with mean base inclination angles of 0°,15°,30°,and 45°.The structures were designed to comply with Chilean seismic codes and standards,and the primary response parameters were compared.To assess the seismic performance of the buildings,nonlinear static(pushover)and dynamic(time-history)analyses were performed with SeismoStruct software.Pushover analyses were used to compare the nonlinear response at the maximum roof displacement and the damage patterns.Time-history analyses were performed to assess the nonlinear dynamic response of the structures subjected to seismic ground motions modified by topographic effects.To consider the topographic modification,acceleration records were obtained from numerical models of soil,which were calculated using the rock acceleration record of the Mw 8.01985 Chilean earthquake.Minor differences in the structure responses(roof displacements and maximum element forces and moments)were caused by the topographic effects in the seismic input motion,with the highly predominant ones being the differences caused by the step-back configuration at the base of the structures.High concentrations of shear forces in short walls were observed,corresponding to the walls located in the upper zone of the foundation system.The response of the structures with higher angles was observed to be more prone to fragile failures due to the accumulation of shear forces.Even though hillside buildings gain stiffness in the lower stories,resulting in lower design roof displacement,maximum roof displacements for nonlinear time-history analyses remained very close for all the models that were primarily affected by the drifts of the lower stories.Additionally,vertical parasitic accelerations were considered for half the time-history analyses performed here.The vertical component seems to considerably modify the axial load levels in the shear walls on all stories. 相似文献
8.
An approximate‐simple method for nonlinear response estimates of reinforced concrete frames subjected to near‐field and far‐field records is presented in this paper. The approximate method is based on equivalent single‐degree‐of‐freedom and linear multi‐degree‐of‐freedom models. In this procedure, the nonlinear maximum roof displacement is estimated using an effective period factor and elastic response spectrum with an equivalent damping. The effective period factor was proposed for far‐field and near‐field ground motion records. For regions of high seismicity, the maximum roof displacement can be estimated by applying an effective period factor of 2.3 and 2.1 for near‐field and far‐field records, respectively, and 9% damped displacement response spectrum. For regions of moderate seismicity, a lower effective period factor of 1.9 and 1.8, for near‐field and far‐field records, respectively, can be applied to estimate the maximum roof displacement. A relationship between linear and nonlinear response of multi‐degree‐of‐freedom systems was also proposed to obtain estimates of the maximum inter‐story drift of nonlinear responding reinforced concrete frames. In addition, the effects of number of ground motion records used in the analyses on the scatters of results were investigated. The required number of ground motions to produce a reliable response was proposed. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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Full-scale measurements are regarded as the most reliable method to evaluate wind effects on large buildings and structures. Some selected results are presented in this paper from the full-scale measurement of wind effects on a long-span steel roof structure during the passage of Typhoon Fanapi. Some fi eld data, including wind speed and direction, acceleration responses, etc., were continuously and simultaneously recorded during the passage of the typhoon. Comprehensive analysis of the measured data is conducted to evaluate the typhoon-generated wind characteristics and its effects on a long-span steel roof. The fi rst four natural frequencies and their vibration mode shapes of the Guangzhou International Sports Arena(GISA) roof are evaluated by the stochastic subspace identifi cation(SSI) method and comparisons with those from fi nite element(FE) analysis are made. Meanwhile, damping ratios of the roof are also identifi ed by the SSI method and compared with those identifi ed by the random decrement method; the amplitude-dependent damping behaviors are also discussed. The fullscale measurement results are further compared with the corresponding wind tunnel test results to evaluate its reliability. The results obtained from this study are valuable for academic and professional engineers involved in the design of large-span roof structures. 相似文献
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武汉军山大桥是跨越长江的中跨跨径很大的斜拉桥，在脉动风作用下，其线性抖振响应较大，动力放大系数基本上大于2。为了比较该桥非线性抖振响应与线性抖振响应的差别，本文根据某地短期的实际风速时程记录资料，在一定的概率下，对该地区100年一遇的极值风速时程进行抖振分析比较。计算结果表明，对于该桥说来非线性影响不是很明显。 相似文献
11.
Non-linear buffeting response analysis of long-span suspension bridges with central buckle 总被引：1，自引：1，他引：0
The rigid central buckle employed in the Runyang Suspension Bridge (RSB) was the first time it was used in a suspension bridge in China. By using a spectral representation method and FFT technique combined with measured data,a 3D fluctuating wind field considering the tower wind effect is simulated. A novel FE model for buffeting analysis is then presented,in which a specific user-defined Matrix27 element in ANSYS is employed to simulate the aeroelastic forces and its stiffness or damping matrices are parameterized by wind velocity and vibration frequency. A nonlinear time history analysis is carried out to study the influence of the rigid central buckle on the wind-induced buffeting response of a long-span suspension bridge. The results can be used as a reference for wind resistance design of long-span suspension bridges with a rigid central buckle in the future. 相似文献
12.
The interaction between membrane structures and their environment can be either static or dynamic. Static interaction refers
to interaction with static air, while dynamic interaction refers to wind and its effects. They can be evaluated by two parameters,
added mass and radiation /aerodynamic damping, which are experimentally investigated in this study. The study includes the
effects of both the static and dynamic interaction on structural dynamic characteristics, and the relationship between the
interaction parameters and the covered area of a membrane structure for the static interaction and the relationship between
the interaction parameters and wind direction and speed for the dynamic interaction. Experimental data show that the dynamic
interaction is strongly correlated with the structural modes, i.e., the interaction of the symmetric modes is much larger
than the anti-symmetric modes; and the influence of the dynamic interaction is significant in wind-induced response analysis
and cannot be ignored. In addition, it is concluded that the structural natural frequency is remarkably decreased by this
interaction, and the frequency band is significantly broadened. 相似文献
13.
将混沌遗传算法(Chaos Genetic Algorithm,简称CGA)引入高层结构的风振控制优化中,对采用黏弹性阻尼器来控制风振响应的高层结构进行参数优化;用Matlab语言编制了均布法、迭代法、简单遗传算法(Simple Genetic Algorithm,简称SGA)和混沌遗传算法的风振控制优化分析程序;对9个高层结构进行风振控制优化,对比了算法程序的计算效率以及无控、均布、迭代、SGA和CGA工况下的结构风振响应。研究结果表明:混沌遗传算法可以应用于高层结构风振控制优化之中;混沌遗传算法的计算效率比简单遗传算法最高提升了29%;经混沌遗传算法优化后,黏弹性阻尼器附加给结构的附加阻尼比与均布和迭代相比最高分别提高了61%和22%,CGA工况的顶层加速度响应与均布和迭代法相比最高分别减小了14%和12%。为高层结构风振控制优化研究提供了新思路,具有一定的理论价值和实际意义。 相似文献
14.
依据自回归(AR)法,确立了考虑风速时程空间相关性的模拟方法,并利用Matlab语言编制了相应的程序。基于上述方法,模拟了某体育场挑篷结构的风速时程,并对所得风速时程离散值进行数理统计分析,结果表明模拟谱与目标谱吻合较好。根据结构风振响应分析的需要,将模拟风速转变为风荷载对结构进行时程分析,获得了结构风振响应,为结构抗风设计提供依据。计算表明,基于风速时程的结构风振响应分析方法可有效分析体育场挑篷的风振响应。 相似文献
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主要研究斜拉桥地震响应中拉索与梁、塔动态相互作用和行波效应的影响,索一桥相互作用的影响是根据结构动力学中广义自由度的概念,把索的振型作为自由度来考虑,通过把索边界节点的位移和索局部振型位移叠加得到索的整体位移,行波效应是通过在不同支承点输人具有一定相位差的同一条地震动模拟.以一座斜拉桥为例进行了数值模拟和参数分析,结果... 相似文献
16.
Grouping response method for equivalent static wind loads based on a modified LRC method 总被引：1，自引：0，他引：1
Wind loading is one of the most important loads for controlling the design of large-span roof structures.Equivalent static wind loads,which can generally aim at determining a specific response,are wid... 相似文献
17.
目的是建立5种被动的动力减振器对长宽比较大的高层建筑侧移-扭转脉动风振反应控制优化设计的统一方法。文中,在建立了5种被动动力减振器对高层建筑侧移-扭转脉动风振反应控制统一的方程的基础上,导出了被动动力减振器对高层建筑侧移-扭转脉动风振反应控制效果最优等效阻尼比和被动动力减振器最优设计参数的基本公式。通过工程实例的计算与分析,本文比较了5种被动动力减振器对高层建筑侧移-扭转脉动风振反应的控制效果,讨论了动力减振器在楼层上设置位置对动力减振器最优设计参数和控制效果的影响,得到了2个有工程价值的重要结论。 相似文献
18.
MR阻尼器对桅杆结构风振响应的智能半主动控制 总被引：1，自引：0，他引：1
本文基于修正的拉格朗日坐标描述法，推导了空间四节点纤绳单元的大位移刚度矩阵的具体表达式。在将桅杆结构离散为空间四节点纤绳单元和梁单元的计算模型的基础上，建立了桅杆结构非线性风振响应分析的有限元方法。根据瞬时最优主动控制的原则，提出了MR阻尼器对桅杆结构风振反应智能半主动控制基于阻尼器位移的“开关—耗能”半主动控制策略。算例结果表明MR阻尼器能有效地减小桅杆结构的风振反应。 相似文献
19.
High-rise buildings are usually considered as flexible structures with low inherent damping. Therefore, these kinds of buildings are susceptible to wind-induced vibration. Tuned Mass Damper (TMD) can be used as an effective device to mitigate excessive vibrations. In this study, Artificial Neural Networks is used to find optimal mechanical properties of TMD for high-rise buildings subjected to wind load. The patterns obtained from structural analysis of different multi degree of freedom (MDF) systems are used for training neural networks. In order to obtain these patterns, structural models of some systems with 10 to 80 degrees-of-freedoms are built in MATLAB/SIMULINK program. Finally, the optimal properties of TMD are determined based on the objective of maximum displacement response reduction. The Auto-Regressive model is used to simulate the wind load. In this way, the uncertainties related to wind loading can be taken into account in neural network’s outputs. After training the neural network, it becomes possible to set the frequency and TMD mass ratio as inputs and get the optimal TMD frequency and damping ratio as outputs. As a case study, a benchmark 76-story office building is considered and the presented procedure is used to obtain optimal characteristics of the TMD for the building. 相似文献