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1.
以液体粘滞阻尼器为振动控制外部装置,主桥采用欧拉伯努利梁,通过中国和谐号动车组CRH380AL、日本新干线Shinkansen700和欧洲高速列车HSLMA8三种不同类型的高速列车对比,模拟分析了高速列车作用下桥梁结构共振响应的影响因素,以及粘滞阻尼器的阻尼系数与安装位置对桥梁结构振动响应的减振效果。研究结果表明,(1)合理有效地布置列车荷载轴距,可使桥梁结构发生基频共振的列车时速在运营时速之外,避免了桥梁结构发生较大振动峰值响应,即桥梁结构的基频共振;(2)随着粘滞阻尼器阻尼系数的增大,桥梁的加速度峰值在列车不同时速下均在减少,对桥梁振动有着不同程度的减振效果;(3)通过合理安置液体粘滞阻尼器,可有效降低高速列车作用下桥梁结构的共振响应;(4)随着粘滞阻尼器与主梁的连接点位置逐渐远离支座,粘滞阻尼器的减振效果逐渐明显;(5)随着粘滞阻尼器与桥台的连接点位置逐渐靠近支座,粘滞阻尼器的减振效果略有提升,但不明显。  相似文献   

2.
以液体粘滞阻尼器为振动控制外部装置,主桥采用欧拉伯努利梁,通过中国和谐号动车组CRH380AL、日本新干线Shinkansen700和欧洲高速列车HSLMA8三种不同类型的高速列车对比,模拟分析了高速列车作用下桥梁结构共振响应的影响因素,以及粘滞阻尼器的阻尼系数与安装位置对桥梁结构振动响应的减振效果。研究结果表明,(1)合理有效地布置列车荷载轴距,可使桥梁结构发生基频共振的列车时速在运营时速之外,避免了桥梁结构发生较大振动峰值响应,即桥梁结构的基频共振;(2)随着粘滞阻尼器阻尼系数的增大,桥梁的加速度峰值在列车不同时速下均在减少,对桥梁振动有着不同程度的减振效果;(3)通过合理安置液体粘滞阻尼器,可有效降低高速列车作用下桥梁结构的共振响应;(4)随着粘滞阻尼器与主梁的连接点位置逐渐远离支座,粘滞阻尼器的减振效果逐渐明显;(5)随着粘滞阻尼器与桥台的连接点位置逐渐靠近支座,粘滞阻尼器的减振效果略有提升,但不明显。  相似文献   

3.
粘滞阻尼器在大型复杂结构减震设计中应用广泛。由于粘滞阻尼器的非线性阻尼力特性,粘滞阻尼器减震结构非平稳随机地震反应分析是一个典型的局部非线性随机振动问题。利用减震结构动力响应时域显式表达式的降维列式优势,仅针对与粘滞阻尼器相关的局部自由度进行非线性迭代计算,提出了局部非线性随机振动问题的时域显式降维迭代随机模拟法,为设置粘滞阻尼器的大型复杂减震结构非线性地震反应分析提供一种高效的随机振动方法。以安装了四个纵桥向粘滞阻尼器的某主跨1200m悬索桥为工程实例,开展E2水准地震激励下的非线性随机振动分析。计算结果显示,设置阻尼器后,主梁的纵桥向位移得到明显控制,降幅达到80%,大桥的关键截面内力也有5%左右的降幅。  相似文献   

4.
在1联(3×168)m连续钢桁梁柔性拱桥设置纵向粘滞阻尼器,采用非线性时程分析方法研究其减震效果。从减小拱脚轴力、墩底内力、墩梁纵向相对位移三方面出发,讨论了粘滞阻尼器各参数对结构地震响应的影响,并与未设置粘滞阻尼器情况下的地震响应进行对比。初选了减震效果较好的阻尼系数C和速度指数ζ,继而在全桥(两联3×168m连续钢桁梁柔性拱)布置该参数的粘滞阻尼器并分析其减震效果。结果表明:固定墩顶的拱脚轴力值在纵向布置粘滞阻尼器后显著减小,而位于活动墩顶的拱脚轴力值个别存在增大情况,且当ζ一定时,C越大减震效果越明显;活动墩顶的墩梁纵向相对位移随ζ的减小和C的增大而减小;以1联连续钢桁梁柔性拱桥为研究对象,所选定的阻尼器在全桥布置后,全桥地震响应的最大正减震率为76.5%,最大负减震率为-21.40%;尽管全桥布置阻尼器后某些位置出现了负减震率,但其地震响应仍然全桥最小;通过对两侧简支钢桁梁粘滞阻尼器的参数优化后,个别位置的地震响应进一步减小,从而提高了全桥的抗震性能。  相似文献   

5.
张敏  李阳 《应用力学学报》2016,(6):1071-1078
振动方程阻尼矩阵对于布置了阻尼器框架结构的振型不再具有正交性,传统的振型解耦法已不再适合于该振动方程的求解。本文采用状态方程直接积分法,研究了线性粘滞阻尼耗能框架结构的地震响应,并与SAP2000有限元软件的分析结果进行了对比,两者误差在5%以内;本文也探讨了阻尼器布置方式对框架结构地震响应的影响。结果表明:减震结构布置阻尼器的楼层,其层间位移角减小较显著;但未布置阻尼器的楼层,其层间位移角较大,甚至会出现层间位移角超过传统抗震结构相应值的现象,因此粘滞阻尼器在结构中应连续布置,不宜在结构中间断;当粘滞阻尼器在结构各楼层均匀布置时,结构各楼层最大位移反应相对传统抗震结构降低很多,约为抗震结构的20%~40%,减震效果较显著,但各楼层阻尼系数可根据均匀布置阻尼器的结构层间位移角优化;阻尼系数优化后,结构各楼层层间位移角差别减小,较为均匀。本文最后提出了线性粘滞阻尼耗能结构地震作用的实用计算方法。  相似文献   

6.
粘滞和粘弹性阻尼器减震结构的随机响应特性   总被引:1,自引:0,他引:1  
利用积分型本构关系,针对带支撑任意线性粘滞和粘弹性阻尼器单自由度耗能结构,建立了微分和积分混合地震响应方程;基于随机平均分析法,推导出耗能结构振幅与相位瞬态联合概率密度函数、位移与速度瞬态联合概率密度函数、位移与速度瞬态响应方差、振幅动力可靠性、振幅首超时间任意阶统计矩的一般解析解;给出了带支撑广义Maxwell阻尼器和广义微分模型阻尼器耗能结构上述各种随机响应特性,从而建立了带支撑任意线性粘滞和粘弹性阻尼器单自由度减震结构的各种随机响应特性分析的统一解析解法。  相似文献   

7.
研究了高效耗能摩擦阻尼器的减震机理。利用力学原理,分析了地震作用下高效耗能摩擦阻尼器的摩擦阻尼力放大系数变化规律,推导了设置高效耗能摩擦阻尼器结构的等效阻尼比计算公式。在此基础上,对分别设置传统摩擦阻尼器和高效耗能摩擦阻尼器的框架结构进行了地震反应分析,结果表明,高效耗能摩擦阻尼器通过将较小的摩擦阻尼力放大可以显著降低结构地震反应,减震效果良好;利用本文给出的等效阻尼比分析得出结构顶层位移反应幅值,与阻尼等效前相应值误差不超过10%。  相似文献   

8.
对设置带支撑Maxwell阻尼器的高层耗能隔震结构的随机风振响应进行了研究。建立结构运动方程,基于传递函数法及随机振动理论,获得结构基于Davenport谱激励下位移和阻尼器受力响应方差,并将其分解为系列标准振子的线性组合,得到结构随机风振响应的解析表达式、阻尼器受力的随机响应、等效风荷载取值,从而建立了带支撑Maxwell阻尼器高层耗能隔震结构的随机风振响应解析分析方法。算例分析表明:支撑刚度对阻尼器的减震效果有着较大的影响,以上部结构风振位移响应为例,阻尼器的支撑刚度为1倍隔震层刚度比支撑刚度为0.001倍隔震层刚度的位移响应减小了30%左右。所获得的解析解对耗能隔震结构的设计和阻尼器的参数优化设计具有重要的意义。  相似文献   

9.
对带支撑粘弹性阻尼器的框架结构减震性能进行了分析.首先分析了粘弹性阻尼器松弛时间系数η和支撑系数ψ等对粘弹性阻尼器复合刚度的影响,在此基础上,采用随机振动理论对设置带支撑粘弹性阻尼器框架结构的振动方程进行求解,研究了改进Kanai-Tajimi功率谱地震激励作用下框架结构层间位移角均方差、结构顶部楼层位移均方差和结构各楼层地震作用均方差等.算例分析表明,阻尼器支撑系数ψ宜根据松弛时间系数η合理取值,只要支撑系数ψ取值足够大,就可忽略支撑对粘弹性阻尼器减震性能的影响,并且阻尼器松弛时间系数η也不宜过大.分析还表明,设置粘弹性阻尼器框架结构各楼层地震作用明显低于无阻尼器框架结构相应值.  相似文献   

10.
通过对6个传统风格建筑钢-混凝土组合梁-柱节点试件,其中包括双梁-柱节点系列及单梁-柱节点系列,在动力循环荷载作用下的试验研究,分析了试件的弹塑性特性及试件在各受力阶段的刚度衰减过程。分析结果表明:双梁-柱试件刚度衰减速率小于单梁-柱试件;附设黏滞阻尼器使试件的刚度及变形能力均有不同程度的提高;各试件刚度衰减均表现出由快到慢的规律;获得了层间位移角的变化与刚度退化之间的关系;试件正、负向弹塑性性能接近,极限层间位移角大于规范规定的限值;附设黏滞阻尼器的试件抗倒塌能力增强;附设黏滞阻尼器的试件耗能能力优于无黏滞阻尼器的试件。由此表明,将消能减震装置与传统风格建筑相结合,可显著提高其力学性能。总体上,结构破坏时形成梁铰机制,符合“强柱弱梁、强节点弱构件”的抗震设防要求。  相似文献   

11.
The nonlinear behaviors and vibration reduction of a linear system with a nonlinear energy sink(NES)are investigated.The linear system is excited by a harmonic and random base excitation,consisting of a mass block,a linear spring,and a linear viscous damper.The NES is composed of a mass block,a linear viscous damper,and a spring with ideal cubic nonlinear stiffness.Based on the generalized harmonic function method,the steady-state Fokker-Planck-Kolmogorov equation is presented to reveal the response of the system.The path integral method based on the Gauss-Legendre polynomial is used to achieve the numerical solutions.The performance of vibration reduction is evaluated by the displacement and velocity transition probability densities,the transmissibility transition probability density,and the percentage of the energy absorption transition probability density of the linear oscillator.The sensitivity of the parameters is analyzed for varying the nonlinear stiffness coefficient and the damper ratio.The investigation illustrates that a linear system with NES can also realize great vibration reduction under harmonic and random base excitations and random bifurcation may appear under different parameters,which will affect the stability of the system.  相似文献   

12.
The purpose of this study is to investigate analytically a single-degree-of-freedom (SDOF) building structure equipped with a friction damper for assessing its vibration control effect. Friction dampers are installed between stories to reduce inter-story displacements of building structures subjected to external loading. They are in general regarded to generate damping forces characterized by Coulomb damping, of which the directions are opposite to the inter-story velocities of building structures. Hence, the building structure model with friction dampers can be represented by a mass-spring-viscous-Coulomb damping system. The building response reduction as a result of damper installation can be provided by observing the damping ratio rather than the friction force contributed by the dampers. Since a large friction damper force is required to attenuate the response of the building due to strong excitation, friction force ratio is directly related to building response reduction, which is the friction force of the damper versus external force. Therefore, damping and friction force ratios are key parameters, playing a main role in selecting an optimal friction damper, which satisfies target response reduction. This study first identifies an SDOF building structure installed with a friction damper for free vibration with initial conditions. A?closed-form expression of normalized displacement is derived in terms of friction force ratio in the time domain. Peak and valley of displacements are also found and then the time when the structure stops is derived with recursive interval number. This study is extended to identify steady-state vibration of the structure by deriving closed-form solution in case of resonance in terms of friction force ratio. Then, the dissipated energy balance is identified for both free and steady-state vibrations. Finally, equivalent viscous damping ratios are derived by using friction force ratio based on dissipated energy balance equation. The derived equations in terms of viscous damping ratio and friction force ratio can provide insight to design a friction damper for reducing structural displacement under external loadings.  相似文献   

13.
根据列车具体的轴距和轴重,建立了和谐号动车组CRH380AL型列车简化模型;对高速铁路两跨连续梁桥采用多自由度欧拉伯努利梁单元进行主梁的模拟,并将液体黏滞阻尼器模拟为有限元阻尼单元;采用Newmark直接积分方法求解了高速列车作用下的连续梁桥运动方程,数值分析了列车车速以及液体黏滞阻尼器的阻尼系数对于高速铁路连续梁桥振动响应的影响。结果表明:黏滞阻尼器对于桥梁具有明显的减振效果,阻尼力不仅与阻尼系数有关还与列车时速有关;同一黏滞阻尼器条件下,桥梁的最大加速度并不随列车速度的增加而单调增加,而是在某些特定列车车速下桥梁的最大加速度出现了峰值,且随着黏滞阻尼器的阻尼系数增大,桥梁振动响应峰值处的最大加速度减幅不同;同一列车时速的条件下,桥梁的减振效果并不是随着阻尼系数的递增呈正比递增,而是随着阻尼系数的增大,阻尼器的减振效果增幅在减小。  相似文献   

14.
主要针对长阻尼孔形式下的流体阻尼器进行分析,在三参数模型的基础上研究了流体粘性发热对流体阻尼力的反馈作用,从而建立了含热能转换与热交换的阻尼器的动力学模型,同时对系统的热平衡状态进行了分析。最后通过数值分析对该时变系统从时域和频域上讨论了粘性发热对隔振效果的影响,发现温度变化对共振频率的漂移及幅值大小的影响较大。  相似文献   

15.
This study is concerned with the analysis and design of the force and displacement transmissibility of nonlinear viscous damper based vibration isolation systems. Analytical algorithms are derived using the Ritz–Galerkin method to evaluate the transmissibility of SDOF displacement vibration isolation and force vibration isolation systems where a nonlinear viscous damper is used as an energy dissipating device. The results reveal that compared to linear dampers, nonlinear viscous dampers can more significantly improve the system vibration isolation performance in a wider frequency range. A procedure is then proposed based on the analysis results to facilitate the design of nonlinear viscous dampers for system vibration isolation purposes. These results have significant implications for the design of vibration isolation systems in many engineering applications.  相似文献   

16.
This article presents the lattice Boltzmann simulation of viscous fingering phenomenon in immiscible displacement of two fluids in porous media. Such phenomenon generally takes place when a less viscous fluid is used to displace a more viscous fluid, and it can be found in many industrial fields. Dimensionless quantities, such as capillary number, Bond number and viscosity ratio between displaced fluid and displacing fluid are introduced to illustrate the effects of capillary force, viscous force, and gravity on the fluid behaviour. The surface wettability, which has an impact on the finger pattern, is also considered in the simulation. The numerical procedure is validated against the experiment about viscous fingering in a Hele-Shaw cell. The displacement efficiency is investigated using the parameter, areal sweep efficiency. The present simulation shows an additional evidence to demonstrate that the lattice Boltzmann method is a useful method for simulating some multiphase flow problems in porous media.  相似文献   

17.
The behaviors of a vibration system suppressed with an impact damper are investigated, where the impact damper is simplified as a combination of spring and viscous damping. The analytical theory for the optimal impact control algorithms for impact damper is developed, and the accurate expressions are derived for the optimal values of the impact damper damping and initial displacement in a single-degree-of-freedom structure. The relation between coefficient of restitution and impact damping ratio is obtained. The investigation shows that the effective reduction of the vibration response is nearly independent of the number of impacts, but primarily related to the type of collision which the impact mass collides with the main mass face-to-face. This theory is generalized to continuous structures. An example of an impact damper in a rotating cantilever beam demonstrates that the impact dampers are suitable for attenuating the impulse response of structures unconditional stable without the requirement of the accuracy of the modal information.  相似文献   

18.
The stability of a cantilever elastic beam with rectangular cross-section under the action of a follower tangential force and a bending conservative couple at the free end is analyzed. The beam is herein modeled as a non-linear Cosserat rod model. Non-linear, partial integro-differential equations of motion are derived expanded up to cubic terms in the transversal displacement and torsional angle of the beam. The linear stability of the trivial equilibrium is studied, revealing the existence of buckling, flutter and double-zero critical points. Interaction between conservative and non-conservative loads with respect to the stability problem is discussed. The critical spectral properties are derived and the corresponding critical eigenspace is evaluated.  相似文献   

19.
本文研究了牛顿流体非稳态Couette流动阶段的边界位移与流体黏性摩擦能耗.在上边界始终保持静止,下边界以恒定速度或恒定内壁剪切应力突然运动的情况下,建立了Couette非稳态流动的数学模型.求解定解问题,获得流体速度分布函数;通过渐近分析,获得不同边界条件下流动充分发展的临界时间,进而获得非稳态过程中的边界位移量.利用边界剪切应力和位移量的结果,计算非稳态过程中移动平板做功;再结合流体动能增加量,计算得出不同边界条件下非稳态流动阶段流体黏性摩擦能耗.  相似文献   

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