电流变阻尼器的动态特性实验研究

设计制造了一种多层滑动极板式电流变阻尼器，使用自制的电流变液，采用正弦激励，进行了这种电流变阻尼器的阻尼特性试验。研究了电流变阻尼器的载荷－位移迟滞特性和载荷－速率迟滞特性，同时研究分析了这种电流变阻尼器的周期能耗特性及等效粘性阻尼特性。结果表明，阻尼器的周期能耗量随外加电场强度的增加而增加，外加电场强度越大，阻尼器的等效阻尼系数越大。阻尼器的阻尼特性体现为库仑阻尼和粘性阻尼的组合，其中随外加电场强度可控的主要是库仑阻尼力，而且库仑阻尼力不仅与外加强度有关，也与阻尼器的运动速度有关。该阻尼器系统是一个强非线性系统，极板间电流变液在低剪切应变率时表现为Bingham塑性流体，在高剪切应变率时流变性态比较复杂，导致载荷－速率迟滞环出现多区域闭合现象。     

粘弹性阻尼器动力设计及其应用的实验研究

本文提出一种圆柱式剪切型粘弹性阻尼器，给出其具有结构阻尼特性的单自由度动力学系统模型，用正弦扫频实验技术实现了对阻尼器动力学特性的测量。通过实验，研究了粘弹性材料动态特性与阻尼器动力学特性的关系，并给出这种关系的数学表示，给出了这类阻尼器的设计方法和基本公式。实验结果表明，应用这种阻尼器可有效控制桁架结构的振动，实现对结构的阻尼控制。     

SMA阻尼器的阻尼特性分析及器件设计方法

提出了SMA中心引线型阻尼器的力学计算模型，以Brinson本构模型为理论依据建立了阻尼器的阻尼特性分析理论及器件设计方法；利用MATLAB编制的仿真软件进行了实例仿真。结果表明SMA阻尼器具有明显的阻尼特性，加上其耐久性和免维护性，适合用于土木工程的结构振动被动控制。     

NEURAL NETWORK MODEL OF MAGNETORHEOLOGICAL DAMPER FOR VIBRATION ISOLATION PLATFORM OF WHOLE-SPACECRAFT

为改善星箭界面振动环境,设计六杆隔振平台,采用磁流变阻尼器作为半主动控制元件,替代原有锥壳过渡支架.对整星隔振平台用磁流变阻尼器进行性能测试,得到反映磁流变阻尼器阻尼特性的实验数据.建立具有两个隐含层的反向传播神经网络对阻尼器进行建模,用于预测磁流变阻尼器阻尼特性以及控制系统设计.提出一种串行算法优化网络结构、权值和阈值,保证网络具有较好的泛化能力和稳定性.仿真结果表明,与参数化模型相比,提出的神经网络模型具有较小的训练误差和较强的泛化能力,能够很好地预测阻尼器的阻尼特性.     

整星隔振用磁流变阻尼器神经网络模型

为改善星箭界面振动环境,设计六杆隔振平台,采用磁流变阻尼器作为半主动控制元件,替代原有锥壳过渡支架.对整星隔振平台用磁流变阻尼器进行性能测试,得到反映磁流变阻尼器阻尼特性的实验数据.建立具有两个隐含层的反向传播神经网络对阻尼器进行建模,用于预测磁流变阻尼器阻尼特性以及控制系统设计.提出一种串行算法优化网络结构、权值和阈值,保证网络具有较好的泛化能力和稳定性.仿真结果表明,与参数化模型相比,提出的神经网络模型具有较小的训练误差和较强的泛化能力,能够很好地预测阻尼器的阻尼特性.     

断油时挤压油膜阻尼器的空气气穴流型及减振特性实验研究

针对挤压油膜阻尼器在断油的工况下开展实验研究,考察阻尼器的气穴现象及其对阻尼器减振特性的影响,结果表明在供油压力较低的工况下,当轴径偏心率仅为0.13时,阻尼器便从外界吸入空气到阻尼器油腔内,气液两相流的流型呈周期性变化,且多为非均相流;在气穴的影响下,阻尼器油腔内出现恒压区,油膜压力大幅减小;等效油膜阻尼系数呈周期性变化,阻尼效果减弱;阻尼器轴径偏心率越大,空气吸入量越大,阻尼器的油膜压力和等效阻尼系数越低。     

三种电流变阻尼器阻尼特性的对比分析

首先简要地介绍了电流变体材料以及电流变阻尼器的基本概念,进而阐明了剪切模式电流变阻尼器、流动模式电流变阻尼器和复合模式电流变阻尼器的工作原理。最后,应用非牛顿流体力学理论给出了它们的阻尼力模型,并对其各自的阻尼特性进行了一些理论分析和探讨。     

具有粘性阻尼器的陀螺系统根轨迹特性分析

研究了含粘性阻尼器并具有陀螺效应的结构系统的根轨迹特性。结合算例着重研究了根轨迹分岔现象,指出当阻尼器位于某些点处时,随着阻尼系数的增大,系统的某两条完整的根轨迹曲线可能会越定越靠近,相遇然后又相互分离。根轨迹的这种分岔现象对于确定阻尼器的安置位置及选定阻尼系数大小有一定参考价值。     

SMA阻尼器在土木结构被动控制中的运用

首先确立了SMA耗能阻尼器的力学模型，以Brinson本构关系为理论依据，基于热力学第一定律建立了耗能阻尼器的热力学非线性方程；然后，建立了在耗能阻尼器作用下的框架结构动力学非线性平衡方程及其求解方法；最后，利用文章编写的仿真软件分别对耗能阻尼器的阻尼特性和框架结构的动力响应进行了实例仿真模拟。结果表明，SMA耗能阻尼器具有明显的阻尼特性；对于结构在地震作用下的动力响应具有明显的抑制效果，结构顶层位移、速度峰值衰减率达50～60％；仿真结果与其他学者的试验结果吻合较好，表明文中所述方法的正确性与适用性。     

结构振动的滑模变结构半主动控制

研究应用磁流变阻尼器(MRD)对结构振动半主动控制的算法和原理。研制并对磁流变阻尼器进行了阻尼特性实验，采用非线性滞回双粘性模型描述磁流变阻尼器的阻尼特性，模型结果与实验结果非常一致。采用滑模控制算法和趋近律方法设计了半主动控制器。利用滑模控制方法所建立的控制器，本文给出了地震激励下结构振动半主动控制算例。计算分析表明，半主动滑模控制具有控制效果明显、鲁棒性好等优点，是一种非常有发展前途的控制方法。     

FREE VIBRATION OF TAUT CABLE WITH DAMPER AND PARALLEL SPRING

分析了拉索-并联弹簧-阻尼器系统的自由振动特性,由系统的运动方程及边界条件 得到其复特征值方程。进一步研究了系统的极限解,由此讨论了拉索-并联弹簧-阻尼器系统的模态变化分区现象。以拉索-并联弹簧-阻尼器系统的二阶模态解为例,给出了模态频率和阻尼比的变化分布区间及其对应振型的变化情况。讨论了系统分区中存在的模态交叉现象;同时也讨论了斜拉索垂度对于一阶振动模态变化规律的影响。研究表明拉索-并联弹簧-阻尼器系统的振动模态演化因并联弹簧-阻尼器的位置不同而存在的明确的分区现象;安装并联弹簧和阻尼器后拉索的模态阻尼比和模态频率均可明显提高。     

转子轴承系统电磁阻尼器的位移反馈振动控制

本文研究在周期激振力作用下转子轴承系统电磁阻尼器的位移反馈振动控制。首先给出受电磁阻尼器控制的一般线性多自由度转子轴承系统的振动方程，控制力和电磁阻尼器结构参数，控制电流等之间的关系式，然后提出在保证系统稳定的前提下，通过位移反馈控制其电流位移增益矩阵应满足的条件；其次以单盘对称转子轴承系统为例，求出转子系统受电磁阻器控制的幅频响应和相频响应；最后给出算例，打印出电磁阻尼器的静态电流，电流位移增益     

摩擦板式电流变阻尼器在抑制转子突加不平衡响应中的应用

设计了用于转子振动控制的摩擦板式电流变阻尼器,建立了电流变阻尼器－转子系统的分析模型,根据文献「７」中建立的突加不平衡模型,理论分析了电流变阻尼器抑制转子系统突加不平衡响应,计算分析结果发现：随着外加电压的升高,电流变阻尼器能有效地抑制突加不平衡响应。     

建筑结构最优阻尼及最优配置研究

利用阻尼来抗震是建筑物最简单的抗震方法,当在阻尼数目少于楼层数时,为使所布置的阻尼达到最优的抗震效果,本文开发了两种最优阻尼配置方法。第一种方法是根据临界激励法确定计算所有可能布置位置中的临界阻尼,选择最小的临界阻尼位置作为最优配置。第二种方法则是根据给定阻尼,计算最优控制效果以确定最优阻尼配置。然后根据实代码遗传算法,在结构抗震效果基本保证的前提下,寻找最优阻尼以降低结构总的阻尼增量。最后给出了一个计算实例。     

Hopf bifurcation analysis of railway bogie

The railway bogie, the most important running component, has direct association with the dynamic performance of the whole vehicle system. The bifurcation type of the bogie that is affected by vehicle parameters will decide the behavior of the vehicle hunting stability. This paper mainly analyzes the effect of the yaw damper and wheel tread shape on the stability and bifurcation type of the railway bogie. The center manifold theorem is adopted to reduce the dimension of the bogie dynamical model, and the symbolic expression for determining the bifurcation type at the critical speed is obtained by the method of normal form. As a result, the influence of yaw damper on the bifurcation type of the bogie is given qualitatively in contrast to typical wheel profiles with high and low wheel tread effective conicities. Besides, the discriminant of bifurcation type for the wheel tread parameter variation is given which depicts the variation tendency of dynamics characteristics. Finally, numerical analysis is given to exhibit corresponding bifurcation diagrams.     

An analytical approach to optimally design of electrorheological fluid damper for vehicle suspension system

This work develops an analytical approach to optimally design electrorheological (ER) dampers, especially for vehicle suspension system. The optimal design considers both stability and ride comfort of vehicle application. After describing the schematic configuration and operating principle of the ER damper, a quasi-static model is derived on the basis of Bingham rheological laws of ER fluid. Based on the quasi-static model, the optimization problem for the ER damper is built. The optimization problem is to find optimal value of significant geometric dimensions of the ER damper, such as the ER duct length, ER duct radius, ER duct gap and the piston shaft radius, that maximize damping force of the ER damper. The two constrained conditions for the optimization problem are: the damping ratio of the damper in the absence of the electric field is small enough for ride comfort and the buckling condition of the piston shaft is satisfied. From the proposed optimal design, the optimal solution of the ER damper constrained in a specific volume is obtained. In order to evaluate performance of the optimized ER damper, simulation result of a quarter-car suspension system installed with the optimized ER damper is presented and compared with that of the non-optimized ER damper suspension system. Finally, the optimal results of the ER damper constrained in different volumes are obtained and presented in order to figure out the effect of constrained volume on the optimal design of ER damper.     

Semi-active hydropneumatic spring and damper system

This paper is concerned with the development of a semi-active hydropneumatic spring and damper system, comprising of a two state hydropneumatic spring and a two state hydraulic damper. The system was specifically developed to improve the ride comfort and handling of large off-road vehicles. The suspension requirements for good ride comfort and handling for heavy off-road vehicles are discussed with special reference to the advantages of semi-active hydropneumatic springs and semi-active dampers. The layout and functioning of an experimental spring and damper unit used for laboratory tests are discussed. Spring and damper characteristics, as well as valve response times for both the semi-active spring and semi-active damper were determined. A single degree of freedom test rig with a sprung mass of 3 tons was used to perform first order ride comfort tests. Tests include step response and random input response. The test rig was also used to evaluate semi-active control strategies for both spring and damper as well as a control strategy for implementing ride height adjustment without using an external hydraulic pump.     

捷联惯性导航减振系统研究

一本文研究车载捷联惯性导航系统的减振问题。对减振系统的设计、减振器的选型与安装等方面进行了讨论，提出减振系统性能测试和数据处理方法，给出了实验结果。分析振动对仪表测试误差和导航计算误差的影响，并提出了减小误差的措施。     

A novel scheme for nonlinear displacement-dependent dampers

In this paper, a novel scheme for nonlinear displacement-dependent (NDD) damper is introduced. The damper is attached to a simple mass-spring-damper vibration system. The vibration system equipped with a NDD damper is mathematically modeled and the nonlinear governing differential equation of the system is derived. To obtain the displacement of the system, the approximate analytical solution of the governing equation is elaborated using the multiple scales method. The advised approximate analytical algorithm is performed for several case studies and is also verified by the numerical fourth-order Runge?CKutta method. In addition, the performance of the NDD damper is analyzed and compared with the performance of the traditional linear damper. It is found that the proposed NDD damper scheme along with the multiple scales method is not only feasible for vibration reduction but also yields satisfactory response performance rather than the existing traditional linear damper.     

A NEW STOCHASTIC OPTIMAL CONTROL STRATEGY FOR HYSTERETIC MR DAMPERS

I. INTRODUCTION Magneto-rheological (MR) ?uid as a smart material possesses fairly good essential characteristics suchas reversible change between liquid and semi-solid in milliseconds with a controllable yield strengthwhen exposed to a magnetic ?eld. A…