汽车磁流变减振器设计准则探讨

提出了微型汽车磁流变减振器的设计准则,建立了磁流变减振器的理论分析模型来预估减振器阻尼力的大小。测试结果表明,减振器的阻尼力由粘性阻尼力和磁场阻尼力组成,随着磁场强度的增加,减振器的阻尼力也增大,基本上符合理论预估值,说明所建立的理论分析模型是可行的。     

电流变减振器用于铣床振动控制的试验研究

试验研究了电流变减振器在铣床颤振控制中的应用。试验发现，电流变减振器的刚度及阻尼随外加电场强度的增加而增大，主振系统的振幅随电场强度的增加而减小。试验表明电流变减振器具有控振效果明显、结构简单的特点。只要场强选取适当，采用电流变减振装置可以控制铣床刀杆系统的颤振。     

Friction behavior of magnetorheological fluids with different material types and magnetic field strength

Magnetorheological (MR) fluid is a type of a smart material that can control its mechanical properties under a magnetic field. Iron particles in MR fluid form chain structures in the direction of an applied magnetic field, which is known as MR effect, resulting in variation of stiffness, shear modulus, damping and tribological characteristics of MR fluid. As MR effect depends on the density of particles in the fluid or the strength of a magnetic field, the experiments are conducted to evaluate the friction property under reciprocating motion by changing the types of MR fluid and the strength of a magnetic field. The material of aluminum, brass, and steel are chosen for specimen as they are the most common material in mechanical applications. The surfaces of specimen are also observed by optical microscope before and after experiments to compare the surfaces with test conditions. The comparing results show that the friction coefficient increases as the strength of a magnetic field increases in regardless of types of MR fluid or the material. Also the density of particle in MR fluid affects the friction characteristic. The results from this research can be used to improve the performance of mechanical applications using MR fluid.     

磁流变阻尼器阻尼性能研究

为了研究新型可控流体磁流变液的特性以及利用以磁流变液为流体的阻尼器的阻尼特性，本文对磁流变液的重要组成部分——磁性微颗粒进行了介绍．并讨论了描述磁流变液的流变模型。在分析现有磁流变阻尼器结构的基础上．提出了一种改进的阻尼器结构。最后对改进结构测试了其性能，分析了影响其性能的各种因素，并提出了目前尚待解决的主要问题。     

模糊控制磁流变阻尼器与磁悬浮装置并联减振研究

针对磁悬浮装置参振质量大、刚度和阻尼低、振动幅值大时抑制振动效果差的问题;提出一种磁流变阻尼器与磁悬浮装置并联减振的方法。由于磁流变阻尼器具有非线性和滞回特性;目前的力学模型还不够精确;为此提出采用模糊控制方法对磁流变阻尼器进行控制;建立了基于TMS320LF2407A DSP的模糊控制磁流变阻尼器与磁悬浮并联减振系统。理论分析与实验结果证明;采用模糊控制磁流变阻尼器与磁悬浮装置并联减振;可以达到理想的减振效果;振动幅值可由0.48mm减小到0.16mm。     

Study on damping properties of magnetorheological damper

To research the properties of a new kind of smart controllable MR (magnetorheological) fluid, in this paper, the rheological models are discussed. On the basis of analyzing the structural forms of MR dampers, an improved structure of the MR damper is introduced; the properties of the novel MR damper are then tested. The experimental results reveal that the Herschel-Bulkley model predicts the force-velocity well; the damping properties of the ameliorated structure of the MR damper have improved; when the excitation is a trigonal signal, the MR damper reveals a thinning effect at high velocity; and when the excitation is a sinusoidal signal, the MR damper reveals a nonlinear hysteretic property between the damping force and relative velocity. Finally, the main unsolved problems have been put forward. __________ Translated from Ningxia Engineering Technology, 2005, 24 (4) (in Chinese)     

磁流变阻尼器优化设计与性能分析

利用磁流变液这种智能材料的力学性能 ,制作了一种双出杆磁流变阻尼器。文中主要讨论了磁流变阻尼器结构设计、磁路设计的基本原理 ,并讨论了结构参数对磁流变阻尼器性能的影响 ,最后优化设计了磁流变阻尼器的结构参数 ,给出了磁流变阻尼器结构参数的匹配关系     

基于多孔泡沫金属材料的简易磁流变阻尼器可行性研究

针对磁流变液阻尼器价格昂贵及不易密封且易失效的问题,提出以多孔泡沫金属材料为载体,解决上述应用的瓶颈问题的新理念。介绍基于多孔泡沫金属材料的简易磁流变液阻尼器的概念设计,并对其可行性进行初步研究,初步研究结果表明多孔泡沫金属可以储存磁流变液,同时磁流变液在磁场作用下可以从泡沫金属溢出并实现阻尼功能。     

磁流变液的流变性能及其工程应用

磁流变液是一种新兴的智能材料，由于其良好的可控性能和力学性能，因而可以广泛应用于航空航天、机械工程、汽车工程、精密加工工程、控制工程等领域。介绍磁流变液的研究进展和有关磁流变液及其性能的研究、磁流变液应用器件的发展情况，分析了磁流变液存在问题和未来发展展望。     

小位移挤压式磁流变阻尼器的实验研究

设计了小位移、大阻尼力特性的挤压式磁流变阻尼器,并进行了相应的实验研究,包括示功特性和阻尼特性,以及所选用的重庆仪表材料研究所磁流变液MRF-01K的饱和磁场强度.实验结果表明,随着电流的增加,减振器示功图曲线包围面积逐渐增大,耗能增加,减振效果增强,其与激振器的激振频率关系不大;由阻尼特性曲线可知,阻尼器的输出力既与阻尼器电流有关,又与激振器频率有关,频率越大,电流越大,输出的力越大.     

Wear Testing of Seals in Magneto-Rheological Fluids©

Magneto-rheological (MR) fluid-based dampers can be used in suspensions to modify ride, handling, and suspension frequencies in autos. We have developed a unique seal wear test method to simulate the wear of rod seals in Magneto-rheological fluid-based dampers. In this test, seal material samples in the form of rectangular coupons are immersed in a bath of MR fluid, and a section of the rod is brought into contact with the seal coupon. The rod is loaded against the coupon with a known normal force, and a variable-frequency reciprocating machine is used to stroke the rod back and forth across the material coupon surface. Test conditions such as normal load, frequency and amplitude of oscillation, and temperature are adjusted to simulate desired conditions. This bench test method ranks various seal materials qualitatively in the correct order (as determined in field tests with these seal materials) in terms of wear and abrasion resistance and constitutes a valid test procedure for the screening of seal materials, MR fluids, and rod surface coatings.     

基于磁流变阻尼器的铁道车辆结构振动半主动控制

在建立铁道车辆柔刚体系统垂直动力学模型的基础上,应用独立模态空间控制理论和最优控制理论,对影响车辆垂直运行平稳性的车体低阶弯曲结构振动和浮沉、点头等刚体振动进行控制。根据铁道车辆悬挂系统的特点,提出采用磁流变阻尼器作为作动器,以降低车体垂直加速度进而改善运行平稳性为目标的半主动控制策略,来实现在性能改善和能量消耗之间的协调,在ADAMS和Matlab/Simulink?环境下,应用机械系统和控制系统联合仿真技术,对采用半主动控制策略的整车性能进行仿真研究。仿真结果显示该半主动控制策略能较好地抑制车体第一阶弯曲模态的结构振动,并可改善车辆运行平稳性,针对铁道车辆系统的磁流变阻尼器在设计上是可行的。     

MODELLING OF A NEW TYPE MR DAMPER

Applying the rule of laminar flow in the gap between two parallel disks, the theoretical model of a new type MR damper is established, the damping characteristic and structural characteristic of the MR damper are analyzed. Experimental results show that the model can reflect the fundamental characteristics of the disk-gap MR damper.     

Modeling and testing of a field-controllable magnetorheological fluid damper

In this study, an experimental and a theoretical study were carried out to predict the dynamic performance of a linear magnetorheological (MR) fluid damper. After having designed and fabricated the MR damper, its dynamic testing was performed on a mechanical type shock machine under sinusoidal excitation. A theoretical flow analysis was done based on the Bingham plastic constitutive model to predict the behavior of the prototyped MR damper. The theoretical results were then validated by comparing them against experimental data, and it was shown that the flow model can accurately capture the dynamic force range of the MR damper. In addition to the flow model, a modified parametric algebraic model was proposed to capture the hysteretic behavior of the MR damper. The superiority of the proposed modified model was shown by comparing it with the Alg model as well as with a widely adopted modified Bouc-Wen model through an error analysis. It is observed that although all the three models are comparable at the excitation velocities of 0.05, 0.10, and 0.15 m/s, the mAlg model is remarkably successful at the highest excitation velocity of 0.2 m/s over the other two. The improvements in the predictions were found to be over 50%, relative to unmodified model especially at lower current inputs. Therefore, it was concluded that the present flow model can be successfully adopted to design and predict the dynamic behavior of MR dampers, while the mAlg model can be used to develop more effective control algorithms for such devices.     

磁流体行为指数对磁流变冲击阻尼器性能的影响

根据应用于火炮的冲击型磁流变(MR)阻尼器的特点,基于Herschel-Bu lkley本构模型,建立了某25 mm火炮磁流变后坐阻尼器的平行板一维层流模型,获得了不同磁场作用下阻尼力随活塞速度的变化规律。根据某单管25 mm火炮的后坐运动方程,计算了不同MR流体行为指数下,火炮的后坐位移和后坐速度,评价了MR流体行为指数对后坐阻尼器行为的影响。     

汽车磁流变减振器设计原理与实验测试

根据磁流变体的滨汉塑性模型描述，提出了混合工作模式的汽车磁流变减振器的设计原理，按照长安微型汽车的技术和磁流变体的性能设计和制作了微型汽车磁流变减振器，并根据长安微型汽车前悬架减振器的技术条件对此进行了实验测试。实验结果表明，提出的设计原理是可行的，对设计特殊阻尼特性的磁流变减振器有一定的指导意义。     

冲击载荷作用下磁流变阻尼器的建模与分析

以某12．7 mm机枪的磁流变(MR)后坐阻尼器为研究对象,基于Herschel-Bulkley本构模型,建立了该MR后坐阻尼器的轴对称一维层流模型。运用ANSYS软件,对该阻尼器的MR阀进行了磁场有限元分析,求得了环状间隙间MR流体的磁通密度。将MR流体流动模型和MR阀有限元结果相结合,建立了不同磁场作用下阻尼力随活塞速度的变化规律,利用这些规律对该阻尼器的落锤撞击试验和实弹射击试验进行了数值仿真。理论与试验结果的对比指出,在低磁场作用的情况下,理论与试验结果具有较好的一致性。     

汽车磁流变半主动悬架系统的7+k自由度动力学模型与模态控制

在全车7自由度模型的基础上，提出了附加司机与乘员一座椅系统的7＋k自由度汽车动力学模型，并给出了在此模型上安装有4个磁流变可控阻尼器的半主动悬架系统的闭环动力学方程。利用独立模态与耦合模态二次优化控制原理，对系统进行了半主动控制律设计。以小轿车的11自由度模型为例进行数字仿真计算分析，说明了采用7＋k自由度车辆动力学模型的合理性以及采用模态控制方法对其进行控制律设计的优点及其良好的总体控制效果。     

Comparative Study on Wear Characteristics between Flow Mode and Shear Mode Magnetorheological Dampers

This comparative study experimentally examines the wear characteristics of magnetorheological (MR) dampers operated in flow mode and shear mode. First, electromagnetic coil structures are designed for two different MR dampers to maximize the field-dependent damping force. Two MR dampers are also designed to have the same volume of MR fluid for reasonable comparison. After identifying the field-dependent damping force at the initial state, the two dampers are operated up to 60,000 cycles using a reciprocating-type wear durability tester. The field-dependent damping forces are then evaluated before and after operation. The wear properties of the MR fluid are investigated using scanning electron microscope (SEM) images that show the changes in the MR fluid particles' size and shape. The surface roughness of the MR damper's piston areas are also measured. In addition, the effects of the permeability of the piston sleeve materials on the wear properties are investigated by selecting three different sleeve materials that have different permeability values: 0.2% carbon steel (S20C), 0.45% carbon steel (S45C), and tool die casting steel (STD-11). The surface roughness of each case is tested and the atomic spectrum is investigated after long operation using energy-dispersive X-ray spectroscopy (EDS) inside the piston. The experimental results obtained from this work indicate that the motion of the operating mode significantly affects the wear characteristics of the MR fluid itself as well as the magnetic effective areas of the MR dampers.     

泡沫金属磁流液阻尼器的优化设计与实验研究

为提高磁流变泡沫金属阻尼器的阻尼力,基于ANSYS有限元仿真软件,以间隙中磁感应强度为优化目标,以活塞工作长度、直径及缸筒壁厚为优化参数,对泡沫金属磁流变阻尼器的各项参数进行优化。组建泡沫金属磁流变阻尼器剪切力测试系统,实验测试阻尼器优化前后的性能。结果表明,施加相同电流及同等剪切速率时,优化后的泡沫金属磁流变液阻尼器输出的阻尼力提高了1.46倍,优化效果明显。