基于TMD的车致箱梁振动控制模型试验研究

为研究调谐质量阻尼器(tuned mass damper,简称TMD)在控制轨道箱梁结构振动中的应用,以高速动车组和CRTS-Ⅱ型板式无砟轨道-箱梁结构为原型,设计制作了几何相似比为10∶1的车-轨-桥耦合振动缩尺模型系统,分析了TMD在不同质量比、不同位置以及不同安装数量等工况下对箱梁顶板和翼板的减振效果。结果表明:TMD质量比为0.02时减振效果优于质量比为0.01时的减振效果,在考虑结构安全及经济性的条件下,可优先选择质量比更大的TMD;不同TMD安装位置对箱梁各部件的减振效果不同,安装TMD的板件处振动响应得到了明显抑制;安装2个TMD对箱梁结构的减振效果优于安装1个TMD,其减振范围也有所提升。研究结论可为高架轨道箱梁结构的减振设计提供参考。

基于多目标灰狼算法的漂浮式风电机组浮台内TMD参数优化

针对漂浮式风电机组浮台内调谐质量阻尼器(TMD)参数调优的问题,以5 MW Barge型漂浮式风电机组为研究对象,采用多目标灰狼算法(MOGWO)优化TMD参数配置。首先,基于欧拉-拉格朗日方程建立浮台内含TMD的漂浮式风电机组动力学模型,采用Levenberg-Marquardt(LM)法进行模型未知参数辨识;其次,同时考虑塔顶和塔基控制目标,采用MOGWO算法优化TMD的刚度和阻尼参数;最后,在不同工况下进行仿真分析。结果表明:相对于传统的单目标优化算法,使用MOGWO算法参数优化后的TMD对风电机组具有更好的振动抑制效果。

悬索桥竖弯涡振MTMD减振控制效果和参数优化研究

为研究多重调谐质量阻尼器(Multiple Tuned Mass Damper,MTMD)抑制桥梁单阶涡振的性能,建立桥梁结构-MTMD系统竖弯涡振广义单自由度动力方程,以某大跨度悬索桥为背景进行MTMD减振控制效果和参数优化分析。采用数值方法求解动力方程,获得系统在简谐涡激力下达到稳态谐振时结构的动力放大系数和MTMD对结构的附加模态阻尼比,并与单一频率调谐质量阻尼器(Single Tuned Mass Damper,STMD)的减振控制效果进行对比,然后以附加模态阻尼比为目标对MTMD进行参数优化。结果表明:MTMD比最优参数STMD拥有更宽的控制频带和更好的减振效果,经优化后的MTMD减振性能优于最优参数STMD。实际应用MTMD时,应选择较大广义质量、5~7种频率规格,并根据二者找到无量纲频率范围和各TMD阻尼比的惟一最优取值。

基于MTMD的管道振动倍频响应减振研究

大型化工管道受管内流体流动、边界约束、振源激励等复杂因素影响,服役期间往往会发生振动,其振动频率相较于土木结构较高,且可能存在多个主要频率成分.若采用单一频率的调谐质量阻尼器(Tuned Mass Damper,TMD),难以达到理想的控制效果,而采用多重调谐质量阻尼器(Multiple Tuned Mass Damper,MTMD)时,受现场条件限制,又存在无法确定最优安装位置等问题.本文开展了基于MTMD的管道倍频响应减振研究.首先,开展了某化工企业丙烷脱氢装置的大型管道现场实测研究,发现管道振动频率存在明显的倍数关系,即倍频现象.其次,建立局部管道有限元模型,分析管道动力特性,提出了基于数值搜索法的MTMD参数设计方法.最后,考虑化工管道现场安装条件的限制,研究了MTMD安装位置对管道减振效果的影响.数值研究结果表明,安装MTMD可有效减小管道振动响应.

预应变SMA⁃TMD对钢框架结构抗震性能影响研究

针对钢结构在地震激励下加速度响应过大的问题,介绍了一种将形状记忆合金(SMA)应用到调谐质量阻尼器(TMD)装置中的解决方案,利用SMA的特性实现有效的自复位和稳定的阻尼,将预应变SMA棒应用到TMD中,提高装置的阻尼性能。通过试验测试及有限元模拟,研究安装施加预应变SMA-TMD的钢框架抗震性能。结果表明:预应变SMA棒不仅有助于自复位,而且还能大大提高SMA-TMD的等效黏滞阻尼比;经过优化的SMA-TMD装置可以大大降低钢框架的地震动响应,并加快地震能量消耗。

桥梁抗风型TMD对车-桥耦合振动系统减振性能研究

为研究桥梁抗风型调谐质量阻尼器(tuned mass damper, TMD)对车辆荷载引起结构振动的减振效果,并揭示车载作用下的TMD激振机理,提出了基于模态动能演化的多自由度结构TMD控制方法,确定了安装TMD的最优设计参数和布设位置;考虑桥梁有限元模型动力求解的通用性,基于桥梁三维动力分析系统BDANS软件建立了车-桥-TMD动力耦合分析系统;以经典单自由度移动弹簧质量过简支梁模型为研究对象,分析了车-桥-TMD系统振动特性,结合某深水区非通航桥梁抗风型TMD工程实例分析了TMD对车致振动的减振效果和机理。研究结果表明:TMD行程幅值与减振效果呈现正相关特点,即行程幅值越大对车-桥动力效应引起的振动减振效果越好;安装TMD可以显著提高结构的等效阻尼比,满足等效阻尼比>1%的工程需求,提高桥梁结构振动的稳定性;TMD在一定条件下可以减小车辆通过时引发桥梁竖向位移冲击效应,最大可减少3%左右;TMD对车-桥2个子系统的加速度瞬态峰值均起到了一定的抑制效果,尤其对桥梁结构竖向振动加速度作用效果明显,安装TMD后的桥梁跨中竖向振动加速度RMS值减少约20%;对大跨钢箱桥梁而言,相比较小的车辆荷载冲击效应,一阶竖弯呈邻跨反对称特性的桥梁结构在车辆通行过程中更容易激起TMD,使桥梁结构获得更佳的减振效果。

基于气动措施和滑轮式TMD的人行景观桥涡振混合控制研究

为了解决传统式调谐质量阻尼器(tuned mass damper, TMD)在控制低频桥梁结构中弹簧静伸长过长的问题,介绍了滑轮式TMD及其用于结构振动控制时的特点,指出滑轮式TMD可以有效减小弹簧静伸长量。以一座人行景观桥为例,研究了采用气动措施和滑轮式TMD对该桥的涡振控制效果。风洞试验结果显示,在最优气动措施下,主梁的涡振振幅减少了一半以上,但仍未达到行人舒适性要求。基于Scanlan线性涡激力模型进行滑轮式TMD的优化设计,在气动措施的基础上进一步辅以滑轮式TMD进行涡振控制。分析结果表明,气动措施结合滑轮式TMD进行涡振控制能够满足行人舒适性要求,并确保滑轮式TMD质量块的工作行程不超过限值。通过同时采用气动措施和滑轮式TMD,可以满足主梁涡振限值、TMD弹簧静伸长量和工作行程等多重要求,从而有效控制主梁的涡振现象。本文提出的混合控制方案为类似工程中的涡振控制提供了有益参考,可为工程实践提供指导。

基于TMD的大跨度斜拉桥风致随机振动控制研究

本文开展基于TMD的大跨度桥梁风致随机振动控制研究.建立了随机风荷载作用下桥梁—TMD系统随机振动响应分析的虚拟激励分析程序.提出了随机振动响应控制的TMD参数优化方法.以西固黄河大桥为背景,开展了实际桥梁的风致振动控制分析.结果表明:基于本文方法TMD参数优化后振动控制效率可提高近9倍,横向随机位移响应的控制效率可达到28.83%,横向随机加速度响应的控制效率可达到28.8%.

一种形状记忆合金半主动TMD系统的试验研究

针对调谐质量阻尼器(tuned mass damper,TMD)系统应用于轻型结构时易失调从而导致减振效果下降的问题,提出了一种新型形状记忆合金半主动TMD系统。该系统利用钢索悬吊质量块并承担其全部重量,使用有效截面为矩形的大尺寸镍钛形状记忆合金棒材,提供TMD系统水平面2个方向不同的抗弯刚度。为了研究该系统的半主动性能,进行了足尺形状记忆合金半主动TMD系统的自由振动试验,通过改变形状记忆合金的工作温度,研究了温度变化对TMD系统频率及阻尼比的影响。研究结果表明,控制形状记忆合金工作温度从-40~+80℃,TMD系统的频率随温度升高呈现升高趋势,而阻尼比随温度升高呈现下降趋势。将该新型形状记忆合金半主动TMD系统应用于受控结构中,一旦TMD失调,可以通过改变形状记忆合金的温度使其重新调谐。因此,设计的新型形状记忆合金TMD系统在轻型结构减振研究中具有一定的工程应用价值和前景。

基于运动形式转化利用转动惯量虚拟平动惯性质量的TMD控制系统

针对调谐质量阻尼器(Tuned Mass Damper,TMD)通常需要较大的附加质量,安装空间受限以及质量块运动时需要较大的行程等问题,基于平动‐转动运动形式相互转化和能量守恒原理,本文提出了利用转动惯量虚拟平动惯性质量的TMD控制系统(Rotary inertia virtualizing translational mass based Tuned Mass Damper,简称RTMD),进行RTMD控制系统的设计概念,以单自由度结构对象为例建立了附加RTMD控制系统的运动方程,分析了RTMD控制系统参数对结构振动控制效果的影响规律。结果表明控制效果与系统的质量比、惯质比、阻尼比等参数密切相关,相关规律也可以推广到一般多自由度结构体系一阶振动的调谐吸振减振控制。进行了模型振动台试验研究,时域分析和频域分析结果均表明,试验结果与基于理论模型的数值分析结果一致性良好,验证了RTMD控制系统理论模型的正确性、设计参数的合理性以及控制系统应用于实际问题的可行性。

TMDs阻变存储器微观机理研究综述

过渡金属硫族化合物(TMDs)阻变存储器具有简单的金属-介质层-金属三明治结构,且功耗低、可缩性好。分析TMDs阻变存储器阻变机理和导电细丝形成特性,为明确阻变存储器机理模拟研究重点提供理论基础。总结分析了国内外存储层TMDs的范德华层间空隙半径、掺杂和缺陷状况与器件性能之间的关系,展望了TMDs阻变存储器的发展趋势和应用前景,为TMDs阻变存储器技术攻关提供支撑。

移动荷载作用下悬浮隧道管体TMD减振分析及优化布置

为减小悬浮隧道管体在移动荷载作用下的动力响应,采用TMD作为振动控制措施并对减振效果进行了分析。将悬浮隧道管体简化为弹性地基梁,采用移动简谐力模拟汽车荷载,通过Morison方程计算管体振动过程中的流体附加惯性效应和阻尼效应,推导建立了移动荷载作用下管体-TMD系统振动控制方程组。采用Newmark-β法进行数值求解,分析了TMD对悬浮隧道管体的减振效果。针对悬浮隧道管体振动特征,提出采用分布式TMD的布置形式,并对移动速度、TMD阻尼比的影响进行了讨论。结论表明:TMD对移动简谐荷载作用下的悬浮隧道管体具有显著减振效果,最大位移减振率在50%以上。由于多阶模态参与振动,单一TMD的有效减振范围有限。在保持总质量不变的情况下,采用分布式TMD可以获得较好的整体减振效果。提高TMD质量比和降低移动荷载速度有助于提高TMD的减振效果。增大阻尼比会减弱TMD的效果,应综合考虑减振效果和工作空间的要求确定。

基于Damper的方向盘抖动问题优化设计

方向盘是顾客使用频次较高的零部件,受发动机等振源影响,在某些工况下方向盘会出现抖动等让顾客感到不适的问题,本文浅析了某车型方向盘高速抖动的原因,在现有方向盘结构上优化设计,增加Damper吸振器,有效解决了方向盘抖动问题,提升了顾客舒适性。

多种分辨率HDMI接口的TMDS信号转为LVDS格式实现方法研究

为了将图像仿真系统输出的高清多媒体接口(High Definition Multimedia Interface,HDMI)最小化传输差分信号(Transition Minimized Differential Signaling,TMDS)转换为摄像头模组接口低电压差分信号(Low-Voltage Differential Signaling,LVDS),文章联合使用ITE68051芯片和现场可编程逻辑门阵列芯片(Field Programmable Gate Array,FPGA)实现了相应的转换。首先,将高清、超高清HDMI接口的TMDS信号通过ITE68051视频处理芯片进行TMDS解码,以双端口方式输出并行RGB数字信号;然后,应用FPGA易编程性的特点,将多种分辨率的RGB信号转换为相应的LVDS信号。联合应用ITE68051和FPGA芯片架构的转换系统,便于视频设备之间的兼容和系统后续升级,为自动驾驶仿真系统的视频信号输入提供了可靠的硬件接口通道。

Seismic control of multi-degrees-of-freedom structures by vertical mass isolation method using MR dampers

Vertical mass isolation(VMI)is one of the novel methods for the seismic control of structures.In this method,the entire structure is assumed to consist of two mass and stiffness subsystems,and an isolated layer is located among them.In this study,the magnetorheological damper in three modes:passive-off,passive-on,and semi-active mode with variable voltage between zero and 9 volts was used as an isolated layer between two subsystems.Multi-degrees-of-freedom structures with 5,10,and 15 floors in two dimensions were examined under 11 pairs of near field earthquakes.On each level,the displacement of MR dampers was taken into account.The responses of maximum displacement,maximum inter-story drift,and maximum base shear in controlled and uncontrolled buildings were compared to assess the suggested approach for seismic control of the structures.According to the results,the semi-active control method can reduce the response by more than 12%compared to the uncontrolled mode in terms of maximum displacement of the mass subsystem of the structures.This method can reduce more than 16%and 20%of the responses compared to the uncontrolled mode in terms of maximum inter-story drift and base shear of the structure,respectively.

Theoretical and Experimental Study on the Performance of Hermetic Diaphragm Squeeze Film Dampers for Gas-Lubricated Bearings

Low damping characteristics have always been a key sticking points in the development of gas bearings.The application of squeeze film dampers can significantly improve the damping performance of gas lubricated bearings.This paper proposed a novel hermetic diaphragm squeeze film damper(HDSFD)for oil-free turbomachinery supported by gas lubricated bearings.Several types of HDSFDs with symmetrical structure were proposed for good damping performance.By considering the compressibility of the damper fluid,based on hydraulic fluid mechanics theory,a dynamic model of HDSFDs under medium is proposed,which successfully reflects the frequency dependence of force coefficients.Based on the dynamic model,the effects of damper fluid viscosity,bulk modulus of damper fluid,thickness of damper fluid film and plunger thickness on the dynamic stiffness and damping of HDSFDs were analyzed.An experimental test rig was assembled and series of experimental studies on HDSFDs were conducted.The damper fluid transverse flow is added to the existing HDSFD concept,which aims to make the dynamic force coefficients independent of frequency.Although the force coefficient is still frequency dependent,the damping coefficient at high frequency excitation with damper fluid supply twice as that without damper fluid supply.The results serve as a benchmark for the calibration of analytical tools under development.

考虑SSI效应时TMD的减震优化设计

土-结构相互作用(SSI)效应可能会对地震作用下调谐质量阻尼器(TMD)的有效性产生重要影响,因此本文研究了考虑SSI效应时TMD对高层建筑的抗震控制性能。针对一个质量分布均匀、层刚度随高度呈线性分布的40层benchmark结构,以结构顶层均方根位移最小为优化目标,采用改进粒子群算法对其在不同地基土条件以及地震波激励下的调谐质量阻尼器参数进行优化设计。优化结果表明,忽略SSI效应可能会造成地震激励下高层结构中TMD减震性能的不恰当估计,TMD的优化参数与地基土类型和地震波种类紧密相关。优化后的TMD可以有效降低结构顶层位移响应且不增加其峰值加速度,优化后的TMD耗散了绝大部分地震输入能量,并大大降低了结构能量。

Vibration attenuation performance of wind turbine tower using a prestressed tuned mass damper under seismic excitation

With the rapid development of large megawatt wind turbines,the operation environment of wind turbine towers(WTTs)has become increasingly complex.In particular,seismic excitation can create a resonance response and cause excessive vibration of the WTT.To investigate the vibration attenuation performance of the WTT under seismic excitations,a novel passive vibration control device,called a prestressed tuned mass damper(PS-TMD),is presented in this study.First,a mathematical model is established based on structural dynamics under seismic excitation.Then,the mathematical analytical expression of the dynamic coefficient is deduced,and the parameter design method is obtained by system tuning optimization.Next,based on a theoretical analysis and parameter design,the numerical results showed that the PS-TMD was able to effectively mitigate the resonance under the harmonic basal acceleration.Finally,the time-history analysis method is used to verify the effectiveness of the traditional pendulum tuned mass damper(PTMD)and the novel PS-TMD device,and the results indicate that the vibration attenuation performance of the PS-TMD is better than the PTMD.In addition,the PS-TMD avoids the nonlinear effect due to the large oscillation angle,and has the potential to dissipate hysteretic energy under seismic excitation.

Development and Application of a Power Law Constitutive Model for Eddy Current Dampers

Eddy current dampers (ECDs) have emerged as highly desirable solutions for vibration control due to theirexceptional damping performance and durability. However, the existing constitutive models present challenges tothe widespread implementation of ECD technology, and there is limited availability of finite element analysis (FEA)software capable of accurately modeling the behavior of ECDs. This study addresses these issues by developing anewconstitutivemodel that is both easily understandable and user-friendly for FEAsoftware. By utilizing numericalresults obtained from electromagnetic FEA, a novel power law constitutive model is proposed to capture thenonlinear behavior of ECDs. The effectiveness of the power law constitutive model is validated throughmechanicalproperty tests and numerical seismic analysis. Furthermore, a detailed description of the application process ofthe power law constitutive model in ANSYS FEA software is provided. To facilitate the preliminary design ofECDs, an analytical derivation of energy dissipation and parameter optimization for ECDs under harmonicmotionis performed. The results demonstrate that the power law constitutive model serves as a viable alternative forconducting dynamic analysis using FEA and optimizing parameters for ECDs.

Parameters Optimization and Performance Evaluation of the Tuned Inerter Damper for the Seismic Protection of Adjacent Building Structures

In order to improve the seismic performance of adjacent buildings,two types of tuned inerter damper(TID)damping systems for adjacent buildings are proposed,which are composed of springs,inerter devices and dampers in serial or in parallel.The dynamic equations of TID adjacent building damping systems were derived,and the H2 norm criterion was used to optimize and adjust them,so that the system had the optimum damping performance under white noise random excitation.Taking TID frequency ratio and damping ratio as optimization parameters,the optimum analytical solutions of the displacement frequency response of the undamped structure under white noise excitation were obtained.The results showed that compared with the classic TMD,TID could obtain a better damping effect in the adjacent buildings.Comparing the TIDs composed of serial or parallel,it was found that the parallel TIDs had more significant advantages in controlling the peak displacement frequency response,while the H2 norm of the displacement frequency response of the damping system under the coupling of serial TID was smaller.Taking the adjacent building composed of two ten-story frame structures as an example,the displacement and energy collection time history analysis of the adjacent building coupled with the optimum design parameter TIDs were carried out.It was found that TID had a better damping effect in the full-time range compared with the classic TMD.This paper also studied the potential power of TID in adjacent buildings,which can be converted into available power resources during earthquakes.