论文摘要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的材料，它在无外加磁场作用时呈现牛顿流体的流动特性，然而在强磁场作用下，其表观粘度在毫秒级的短时间内增加几个数量级以上，并呈现类似固体的力学性质，而且粘度的变化是连续，可逆的即一旦去掉磁场后，又变成可以流动的液体。磁流变效应连续、可逆、迅速和易于控制的特点使得磁流变液装置将广泛应用于汽车、机械、建筑、航空、医疗等领域。被认为是未来最具有前途的智能材料之一。5496
磁流变液离合器是一种利用磁流变液剪切应力进行离合器的一种装置，它传递的力矩随外加磁场的变化迅速变化。在没有磁场作用的情况下，磁流变液处于液体状态，离合器的离合力矩仅为粘性阻力。当有一个外加磁场的作用是，磁流变液中的极性粒子马上被极化并沿着磁力线方程成链状分布。这种链状结构就使磁流变液的剪切应力增大，表现出塑性体的特性，因此离合器就可以传递一定的力矩。力矩的大小可以通过调节磁场强度的大小来控制。磁流变离合器具有传动平稳、均衡、结构简单、紧凑、操作简便、能耗低、寿命长等优良性能。
在本论文中首先对磁流变液的材料及流变特性进行了介绍，对磁流变液本构模型进行了分析。对磁流变液的传力方式进行了讨论，并根据剪切模式建立了磁流变液的传力模型，完成了圆筒式磁流变液离合器的设计与样品加工，得出了基本设计公式，并对该离合器的性能进行了测试分析，实验证明磁流变液基于磁场强度的改变可以传递不同的转矩与转速，磁流变液离合器有很大的工程应用前景。
关键词：磁流变液   离合器   传力模型  实验分析 毕业论文
THESIS ABSTRACT
Magnetorheological (MR) fluids consist of stable suspensions of particles in a carrying fluid such as silicone oils, responding to an applied magnetic field in their rheological behavior. In the absence of applied magnetic field, MR fluids exhibit Newtonian-like behavior. Upon application of a magnetic field, the suspended particles in the MR fluids become polarized and aligned in the direction of the magnetic field. The fluids behave as a semi-solid having a controllable yield stress. The yield stress of MR fluids increase as the applied magnetic field increase. The feature provides reversible, quiet, rapid response interfaces between electronic controls and mechanical systems.
An MR fluid clutch device achieves braking by shear force of the MR fluid. An MR fluid clutch has the property that its torque changes quickly in response to an external magnetic field. In the absence of an applied magnetic field, the torque is the viscous force of MR fluids in liquid state. When the external magnetic field is applied, the suspended particles in the MR fluids become polarized and gathered to form chain-like structure. These chain-like structures restrict the movement of the MR fluids, thereby increasing the yield stress of the fluids. The clutch can be achieved by utilizing the shear stress of the MR fluids. The torque can be adjusted continuously by changing the magnetic field strength.
In this paper, the rheological behavior of MR fluids is introduced and the constitutive equation is analyzed, then, the design method of the MR fluids clutch is investigated theoretically. The equation of the torque transmitted by the MR fluids in the clutch is derived to provide the theoretical foundation in the design of the clutch. The results of the experiment of the MRF clutch show that the MR fluid could transmit torque in response to an external magnetic field.
Keywords: Magnetorheological fluids(MRF), clutch, mechanical model, experiment.
目录
1   绪论    6
•1.1课题简介    6 磁流变液可控阻尼离合器的设计+CAD图纸:http://www.751com.cn/jixie/lunwen_2550.html