Wang Huixing, Zhang Guang, Wang Jiong
School of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
School of Civil and Environmental Engineering, University of Technology Sydney, Ultimo 2007, Australia.
Materials (Basel). 2019 Jul 30;12(15):2431. doi: 10.3390/ma12152431.
This paper investigates the quasi-static rheological properties of lithium-based magnetorheological (MR) grease under large deformation. Three types of lithium-based MR grease comprising different mass ratios of carbonyl iron (CI) particles and lithium-based grease were prepared. The dependence of the magneto-induced stress-strain curves for MR grease on CI particles content, shear rate, and shear deformation under quasi-static monotonic shear conditions were tested and discussed. The results demonstrate that the shear rate dependence of the maximum yield stress is significantly weakened by the magnetic field, and this weakening is further enhanced as the CI particles content of MR grease increases. In addition, to evaluate and characterize the behavior of the cyclic shear-stress curves of MR grease under quasi-static condition, cyclic shear tests under different controlled conditions, i.e., CI particles content, shear rate, shear strain amplitude, and magnetic field strength, were conduct and analyzed. The magneto-induced shear stress of MR grease with higher CI particles content shows a sharp decrease during the transition from loading to unloading. Moreover, the experiment results also show that the damping characteristics of MR grease are highly correlated with CI particles content, shear strain, and magnetic field strength.
本文研究了锂基磁流变（MR）润滑脂在大变形下的准静态流变特性。制备了三种不同羰基铁（CI）颗粒与锂基润滑脂质量比的锂基MR润滑脂。测试并讨论了准静态单调剪切条件下MR润滑脂的磁致应力-应变曲线对CI颗粒含量、剪切速率和剪切变形的依赖性。结果表明，磁场显著削弱了最大屈服应力对剪切速率的依赖性，并且随着MR润滑脂中CI颗粒含量的增加，这种削弱进一步增强。此外，为了评估和表征MR润滑脂在准静态条件下循环剪切应力曲线的行为，进行并分析了在不同控制条件下，即CI颗粒含量、剪切速率、剪切应变幅值和磁场强度下的循环剪切试验。CI颗粒含量较高的MR润滑脂的磁致剪切应力在从加载到卸载的转变过程中呈现急剧下降。此外，实验结果还表明，MR润滑脂的阻尼特性与CI颗粒含量、剪切应变和磁场强度高度相关。
