磁流变液装置及其在机械工程中的应用

磁流变液是一种在磁场作用下,其流变学性能可作出迅速响应,且易于控制的新型智能材料。基于磁流变液的装置包括阻尼器、制动器、离合器、抛光装置和液压阀等,有很大的潜在发展前景,有些已在汽车、健身设备和抛光机械等工程领域取得商品化应用。本文在分析磁流变液装置工作模式的基础上,对近十年来磁流变液装置（尤其是阻尼器）以及这些装置在机械工程领域的应用进行了分类和全面综述,并对其应用前景进行了展望。     

精密磁流变抛光装置的设计与应用

在介绍了磁流变抛光的基本原理基础上,对磁流变抛光的两种不同结构的装置进行了优缺点比较,从影响抛光效率和最终表面精度考虑,确定了最终的装置设计方案,给出了抛光装置的关键部件的设计,并用磁流变抛光加工了直径83mm的BK9光学平面玻璃工件,获得了Ra0.702nm的表面精度.     

磁流变液减振器的研究及应用现状

简要介绍磁流变阻尼器的工程应用，分析磁流变阻尼器的力学模型及其特征。     

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。     

磁流变技术及其在机械工程中的应用(续)

3　磁流变技术在机械工程中的应用3.1　应用于精密加工　　磁流变抛光是一种新兴的磁场辅助的液体动力抛光技术[3] 。一般来说磁流变抛光过程如图 3所示 ,一个凸形工件被安装在移动壁上的某一固定高度的位置上 ,于是工件表面与移动壁之间就形成一个汇集间隙。一个电磁线圈置于移动壁的下方 ,通电后在间隙附近产生一个非均匀的磁场 ,磁场梯度与移动壁垂直。磁流变液被送到电磁线圈正上方的移动壁上 ,磁流变抛光液被磁场梯度朝移动壁方向压缩 ,从而使移动壁获得运动速度 ,同时磁流变液在进入汇集间隙之前就变成弹性的宾汉流体。于是弹性的磁流…     

磁流变液及其工程应用

磁流变液是一种在外加磁场作用下流变特性发生急剧变化,、且该变化连续、快速、可逆、可控的新型智能流体.本文介绍了磁流变液的组成,并对其流变机理进行了阐述.同时,该文还给出了磁流变液在汽车半悬架、制动器、传感器、精密研磨和抛光等工程应用和发展.     

磁流变液软启动装置设计研究

介绍了盘式结构磁流变液软启动装置的工作原理及设计方法。利用磁流变液Bingham模型和曲线拟合,对磁流变液的磁学特性进行了研究,推导出其力矩传递的计算公式,为磁流变液软启动装置的设计与研究提供了参考和依据。     

电/磁流变技术在机械工程中的应用(上)

电／磁流变液（ERF／MRF）是在电／磁场作用下，其流变学性能可迅速响应，且易于控制的新型智能材料。基于电／磁流变技术的装置包括阻尼器、制动器、离合器、抛光装置和液压阀等，都有很大的潜在发展前景，有些已在汽车、健身设备和抛光机械等工程领域取得商品化应用。在分析电／磁流变液装置工作模式的基础上，对近十年来电／磁流变液装置以及这些装置在机械工程领域的应用进行了分类和全面综述，对其存在的问题及应用前景进行了展望。     

电/磁流变技术在机械工程中的应用(下)

电／磁流变液（ERF／MRF）是在电／磁场作用下，其流变学性能可迅速响应，且易于控制的新型智能材料。基于电／磁流变技术的装置包括阻尼器、制动器、离合器、抛光装置和液压阀等，都有很大的潜在发展前景，有些已在汽车、健身设备和抛光机械等工程领域取得商品化应用。本文在分析电／磁流变液装置工作模式的基础上，对近十年来电／磁流变液装置以及这些装置在机械工程领域的应用进行了分类和全面综述，对其存在的问题及应用前景进行了展望。     

基于微孔金属材料的磁流变液阻尼特性研究

针对存于规则微孔板的磁流变液(MRF)在磁场作用下产生正应力的现象进行了实验研究,实验结果表明:以微孔金属铝板为载体储存的磁流变液在磁场作用下能从微孔中溢出并能在两平行板产生正应力从而实现阻尼功能,本文研究了产生正应力的大小与磁场强度、剪应变及工作间隙关系。     

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)     

Optimal control of structural vibrations using a mixed-mode magnetorheological fluid mount

In this work, a mixed-mode magnetorheological (MR) mount is proposed and applied to the vibration control of a flexible beam structure subjected to external disturbances. On the basis of non-dimensional Bingham number, an appropriate size of the MR mount is designed and manufactured. After experimentally evaluating the field-dependent damping force of the MR mount, a structural system consisting of a flexible beam and vibrating rigid mass is established. The governing equation of motion of the system is derived and expressed as a state space control model. A linear quadratic Gaussian (LQG) controller is then designed in order to attenuate the vibration of the structural system. The controller is empirically realized and control responses such as acceleration and displacement of the structural system are evaluated and presented in frequency domain.     

旋转式磁流变测试仪的设计与研究

由于磁流变液的应用前景广阔,而市场上磁流变液性能测试系统相对短缺,为了更好地促进磁流变液的工程应用,有必要研究磁流变液的性能测试仪.通过理论计算和实验验证的方法,设计了一种磁流变旋转式测试仪,用实测的办法验证了磁场理论计算的正确性.测试表明,当电流为1.6A时磁场达到0.5582T,MRF4的剪切应力达到70.12KPa,当电流为1.4A,磁场为0.5483T,剪切屈服强度51.6KPa.     

一种磁流变液性能测试用的凹字型磁路结构设计与研究

剪切屈服应力是反映磁流变液流变特性的主要参数之一,稳定可控的磁场直接影响磁流变液剪切屈服应力的测量精度,因此磁场设计是否合理对磁流变液的流变性能测试具有重要的影响。针对外置式线圈产生的磁场强度较低且存在漏磁现象、对称式线圈中磁流变液装载不便导致测量过程持续性差等问题,设计了一种凹字型磁路,通过调整线圈位置来改变磁场结构,使磁力线垂直穿过磁流变液流动方向,同时可拆卸的组合式磁路设计在保证磁场强度需要的前提下实现了磁流变液的连续性测量。此外,还分析了不同电流下的磁场强度分布规律,并基于优化的磁路开展了磁流变液剪切屈服应力等力学性能参数的测试。与主流标准测试仪器相比,具有凹字型磁路结构的磁流变液测试系统所测得的剪切屈服应力平均相对偏差值约为10%,重复误差在6.34%以内,说明该磁路结构是磁流变测试中磁场装置设计的一种可行方法。     

对磁流变抛光技术中磁场的分析

本文对磁流变抛光(magnetorheological finishing)过程中所采用的梯度磁场,以及磁流变抛光液（MRP fluid）中的磁性颗粒在磁场中的受力情况进行了分析,进而证明了该磁场满足磁流变抛光的要求。最后以实验对其进行了验证。     

用磁流变液实现软启动

提出把磁流变液作为电动机软启动装置的工作介质，介绍了磁流变液的特性，利用磁流变液屈服应力的Bingham塑性模型，分析了用磁流变液实现电动机软启动的原理，推导了磁流变液软启动器传递力矩的计算公式。     

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.     

界面变形对磁流变传动装置传动性能的影响

为了得到界面变形对磁流变传动装置传动性能的影响规律,总结了变形界面的产生形式,采用数值计算方法,从电磁场和液膜传动能力两方面分析了变形界面的传动性能,并进行了相关实验研究,结果表明:传动圆盘的正常变形量小于100 μm,变形后工作间隙磁场变化量较小,一般小于0.01 T,约占工作间隙磁场的2％;变形对毫米厚度液膜传动性能的影响很小;对于较小变形量,界面变形并不能显著影响磁流变液的传动能力;对于较大变形量,由于磁流变液液膜剪切和挤压效应产生的剪切力作用,磁流变液扭矩传递能力有一定提升,但是这种剪切力不可调节,降低了磁流变传动装置的调节性能.     

磁流体研磨装置中磁场加工区的设计

针对特定的加工要求 ,设计磁流体研磨装置中磁场加工区的重要参数 ,并分析验算设计的合理性     

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.