Wang Huixing, Zhang Guang, Wang Jiong
School of Mechanical Engineering, Nanjing University of Science and Technology Nanjing 210094 People's Republic of China
School of Civil and Environmental Engineering, University of Technology Sydney Ultimo 2007 Australia.
RSC Adv. 2019 Aug 29;9(47):27167-27175. doi: 10.1039/c9ra04987h.
An experimental study was conducted to explore the normal force of lithium-based magnetorheological (MR) grease under quasi-static shear. Firstly, MR grease with various carbonyl iron (CI) particles content was prepared. Then the influence of magnetic field strength, CI particles content, shear rate and temperature on the normal force-strain curves for MR grease under a quasi-static monotonic shear condition were investigated. The results exhibit that the normal force of MR grease under quasi-static monotonic shear decreases first and then maintains constant along with the increase of shear strain, and the critical strain is affected by the magnetic field strength and CI particles content. Finally, the normal force shear strain curves under different magnetic fields and shear strains were obtained by using quasi-static cyclic shear. It was found that the normal force of MRG-70 under quasi-static monotonic shear exhibits peak phenomenon at the beginning of the unloading stage, and the peak value increases with the enlargement of shear strain. Furthermore, when the strain amplitude is higher than 40%, normal force exhibits an abrupt change during the transition from the loading stage to the unloading stage.
进行了一项实验研究，以探究锂基磁流变（MR）润滑脂在准静态剪切下的法向力。首先，制备了具有不同羰基铁（CI）颗粒含量的MR润滑脂。然后，研究了磁场强度、CI颗粒含量、剪切速率和温度对MR润滑脂在准静态单调剪切条件下法向力-应变曲线的影响。结果表明，MR润滑脂在准静态单调剪切下的法向力随着剪切应变的增加先减小后保持恒定，且临界应变受磁场强度和CI颗粒含量的影响。最后，通过准静态循环剪切获得了不同磁场和剪切应变下的法向力-剪切应变曲线。发现MRG-70在准静态单调剪切下的法向力在卸载阶段开始时出现峰值现象，且峰值随剪切应变的增大而增大。此外，当应变幅值高于40%时，法向力在从加载阶段过渡到卸载阶段时会出现突变。
