Wang Hongyun, Bi Cheng, Zhang Yongju, Zhang Li, Zhou Fenfen
College of Aeronautics, Taizhou University, Taizhou, 318000, Zhejiang, China.
Sci Rep. 2021 Apr 26;11(1):8887. doi: 10.1038/s41598-021-88407-0.
Compressions of magnetorheological (MR) fluids have been carried out under instantaneous magnetic fields. The yield strength of the MR fluid in compressive mode has been derived by assuming that it was a transformed shear flow in Bi-visous model. The compressive stresses have experimentally studied under different magnetic fields, different initial gap distances and different compressive velocities. The nominal yield shear stresses of the compressed MR fluid under different influential factors have been calculated. The compressive stress increased in a power law as the applied magnetic field increased, while it decreased as the initial gap distance and the compressive velocity increased. With the increase of magnetic field, the difference between the nominal yield shear stress curves increased, and the exponents of the power law increased with the increase of the magnetic field strengths. A larger initial gap distance and a lower compressive velocity resulted in a higher nominal yield shear stress under the same instantaneous magnetic field. The achieved results of the nominal yield shear stress with magnetic field seemed to deviate from the prediction of dipole model, and the chain structure aggregation effect, the sealing effect and the friction effect by compression should be considered.
在瞬态磁场下对磁流变（MR）流体进行了压缩实验。通过假设其为双粘性模型中的转换剪切流，推导了压缩模式下MR流体的屈服强度。研究了在不同磁场、不同初始间隙距离和不同压缩速度下的压缩应力。计算了不同影响因素下压缩MR流体的名义屈服剪切应力。随着外加磁场的增加，压缩应力呈幂律增加，而随着初始间隙距离和压缩速度的增加，压缩应力降低。随着磁场强度的增加，名义屈服剪切应力曲线之间的差异增大，幂律指数也随之增加。在相同的瞬态磁场下，较大的初始间隙距离和较低的压缩速度导致较高的名义屈服剪切应力。名义屈服剪切应力随磁场的实验结果似乎偏离了偶极子模型的预测，应考虑链结构聚集效应、密封效应和压缩摩擦效应。
