南京理工大学 机械工程学院， 南京 210094
出版日期:2019-03-28发布日期:2019-03-28通讯作者:王炅，男，教授，博士生导师，E-mail：wjiongz@njust.edu.cn.作者简介:汪辉兴（1990-），男，安徽省安庆市人，博士生，主要研究方向为智能材料与结构.基金资助:国家自然科学基金资助项目（51675280）Rheological Properties of Magnetorheological Grease Under Shear Mode
WANG Huixing,ZHANG Guang,OUYANG Qing,WANG JiongSchool of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
Online:2019-03-28Published:2019-03-28摘要/Abstract
摘要： 磁流变脂材料无沉降、密封结构简单、制备容易，因而具有巨大工程应用前景，在剪切模式下的流变特性是磁流变脂缓冲器件设计和应用的基础.采用商业润滑脂为基体，制备了羟基铁粉质量分数分别为30%、50%和70%的磁流变脂.利用稳态剪切测试分析了不同铁粉质量分数的磁流变脂的黏度、剪切应力、屈服应力随剪切速率和磁场变化情况，结果表明：磁流变脂的本构关系可用Bingham模型进行描述，且在一定范围内，羟基铁粉质量分数越高，磁流变脂的黏度和剪切应力可调范围越广.以铁粉质量分数为70%的磁流变脂为例，运用大振幅振荡剪切的方法，确定线性黏弹性区间和非线性黏弹性区间的临界应变幅值为 0.02%；计算该型磁流变脂在磁感应强度为 0.96T 时的屈服应力为 24.7kPa，磁致储能模量为 1.17MPa，相对磁流变效应高达 3814%.
关键词: 磁流变脂, 本构关系, 大振幅振荡剪切, 屈服应力, 磁流变效应
Abstract: Magnetorheological grease (MRG) has wide application prospect in the field of engineering due to the distinguished advantages such as, no settlement, simple sealing and simple preparation. The rheological properties of MRG are the basis for the design of magnetorheological absorber. In this study, lubricating grease based MRG with 30%, 50% and 70% weight fraction of carbonyl iron (CI) were prepared. Rheological properties including shear viscosity and shear stress of MRG with different CI weight fraction were examined from steady shear with and without magnetic fields applied. It is found that the constitutive relation of MRG can be described by Bingham model, and the higher the weight fraction of CI particles is, the wider adjustable range of shear viscosity and shear stress of MRG can reach. The critical strain between linear viscoelastic range and nonlinear viscoelastic range of MRG with 70% CI weight fraction obtained by using the large amplitude oscillatory shear method is 0.02%. In addition, the yield stress is 24.7kPa under the magnetic field of 0.96T; the maximum magneto-induced storage modulus is 1.17MPa; the relative magnetorheological effect reaches as high as 3814%.
Key words: magnetorheological grease (MRG), constitutive relation, large amplitude oscillatory shear, yield stress, magnetorheological effect
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