【作者】 刘成；

【导师】 贺建民；

【作者基本信息】 重庆理工大学 ， 机械设计及理论， 2010， 硕士

【摘要】 磁流变液(MR fluids)是一种在外加磁场作用下流变特性发生急剧变化的材料,其流变特性可由外加磁场连续控制。无外加磁场作用时,它表现为牛顿流体特性;在外加磁场作用下,其流体结构和性能会在毫秒级短时间内迅速变化,表观黏度系数增加几个数量级以上,其流动表现出Bingham塑性体行为,具有黏性和塑性特性。改变外加磁场强度,可控制其屈服应力。基于这一特性设计的磁流变液制动器具有制动平稳、结构简单、容易控制、响应快、能耗低等优点,在工程领域具有广泛的应用前景。本论文设计的磁流变液制动器是一种利用磁流变液剪切应力来进行制动的装置,它的制动力矩随外加磁场的变化而变化。为建立磁流变液制动器的设计方法,本论文分析了国内外对磁流变液材料及其应用的研究现状,把磁流变液的屈服应力可由外加磁场控制的特长与机械设计方法相结合,分析了磁流变液在圆盘式磁流变液制动器和圆筒式磁流变液制动器中的黏塑性流动,分别建立了制动力矩方程,发展了磁流变液制动器的设计方法,为磁流变液制动器的设计提供了理论基础。论文的主要研究工作如下:(1)介绍了磁流变液材料的组成、磁流变效应、磁流变液材料的主要性能及磁流变器件的研究现状。(2)基于Bingham模型,结合磁流变液制动器的工作原理,分别分析了磁流变液在圆盘式磁流变液制动器和圆筒式磁流变液制动器中的流动,建立了相对应的流动方程,并以此得出了圆盘式磁流变液制动器和圆筒式磁流变液制动器制动力矩的计算公式。(3)分析了磁流变液制动器的两个基本设计准则,进行了圆盘式磁流变液制动器和圆筒式磁流变液制动器的结构设计、磁路设计以及励磁线圈的外部控制电路设计。在一定程度上拓展了磁流变液制动器的设计方法。(4)利用ANSYS软件对圆盘式磁流变液制动器和圆筒式磁流变液制动器进行了磁回路仿真分析,并利用仿真结果指导圆盘式磁流变液制动器和圆筒式磁流变液制动器的结构设计和各零部件的选材设计。(5)建立了磁流变液制动器的特性实验方案。更多还原

【Abstract】 Magnetorheological (MR) fluids is a dramatic change in rheological properties of the material with application of a magnetic field, which are regarded as the intelligent materials that respond to an applied magnetic field with a change in their rheological properties. In the absence of an applied magnetic field, MR fluids exhibit Newtonian-fluid-like behavior. With application of a magnetic field, its structure and properties changing rapidly within a few milliseconds, the apparent viscosity coefficient increased more than several orders of magnitude. These fluids exhibit a Bingham plastic behavior with the yield stress dependent upon strength of applied magnetic field. Thus MR fluids are viscoplastic fluids because they have the properties of both viscosity and plasticity. Based on this characteristic,Magnetorheological fluid brake is designed to have smooth braking, simple structure, easy to control, fast response, low energy consumption and other advantages. It has widespread application prospect in engineering.Magnetorheological fluid brake device achieves braking by shear force of the MR fluids. Magnetorheological fluid brake has the property that its braking torque changes quickly in response to an external magnetic field.In order to establish the design method of the Magnetorheological fluid brake, in this paper, the MR fluids materials and their applications have been analyzed. Based on the properties that the yield stress of MR fluids can be controlled by applied magnetic field, the viscoplastic flow of MR fluids in the Disk type Magnetorheological fluid brake and Cylindrical Magnetorheological fluid brake are investigated. The equations for the braking torque in the Magnetorheological fluid brake have been established. They provide the theoretical foundation for the design of the Magnetorheological fluid brake. The main work and conclusions in this paper are as follows:(1)The composition of MR fluids, MR effect, and the main performance of MR fluids are presented and introduced.(2)Based on the Bingham model, combined with the working principle of Magnetorheological fluid brake, the viscoplastic flow of MR fluids in the Disk type Magnetorheological fluid brake and Cylindrical Magnetorheological fluid brake are analyzed. The equations for the viscoplastic flow of the MR fluids in Magnetorheological fluid brake are established. The equations for the braking torque in the Magnetorheological fluid brake have been derived.(3)The two basic design principles of Magnetorheological fluid brake are analyzed. The magnetic back track and the control circuits of excitation coil of Disk type Magnetorheological fluid brake and Cylindrical Magnetorheological fluid brake are designed.(4)Utilize ANSYS software to carry out the imitation analysis of magnetic back track, and use the results to guide the design of Disk type Magnetorheological fluid brake and Cylindrical Magnetorheological fluid brake.(5)The experiment scheme of Magnetorheological fluid brake is established.。更多还原