Study on the Influence of Temperature–Magnetic Field Coupling on the Mechanical Properties of Magnetorheological Fluids

Abstract

The composition of a magnetorheological fluid (MRF) usually includes magnetic particles, a carrier fluid, and additives. Among them, the magnetic particles and carrier fluid are the main sources of the mechanical properties of the MRF. The changes of the related properties of the two will affect the mechanical properties of the MRF directly or indirectly. Herein, first, the temperature–magnetic field characteristics are analyzed during the MRF working process. Then, the influence mechanism of temperature and magnetic field changes on the properties of the magnetic particles and carrier liquid are analyzed. On this basis, the traditional Bingham model is improved and optimized, in which the temperature variable is introduced to represent the effect of temperature–magnetic field coupling on the shear stress of the MRF. Finally, parameter fitting and simulation are carried out for the optimized model, and the self‐made shear stress of the MRF measuring device with temperature‐control function is used to experimentally verify the accuracy of the optimized model. The comparison and verification of the results show that the optimized model can better represent the variation of shear stress of an MRF with temperature and magnetic field than the traditional Bingham model.

Structural Design and Lubrication Properties under Different Eccentricity of Magnetic Fluid Bearings

“…Given a magnetic fluid pressure of 5 MPa, Equation ( 9) was calculated using MATLAB to obtain the relationship between the viscosity of the magnetic fluid lubrication film under the action of a magnetic field and the variation in temperature and magnetic field as shown in Figure 6. As can be seen in Figure 6, the viscosity of the magnetic fluid gradually increases with increasing magnetic induction, and the growth trend is similar to the magnetization curve, and the viscosity of the magnetic fluid stabilizes when the magnetic induction is greater than 0.4 T. This also indicates that the saturation magnetization strength of this magnetic fluid is around 0.4 T. Under the action of the magnetic field, the magnetic particles within the magnetic fluid are arranged in a chain-like structure along the magnetic field direction by the magnetic moment, which increases the resistance to flow, the viscosity of the magnetic fluid increases and the load-bearing capacity increases [28,29]. Figure 7 shows the variation in magnetic fluid viscosity with magnetic field at different temperatures.…”

Numerical simulation of effectively driving the trajectory of magnetic particles in a Newtonian fluid using a uniform magnetic field

“…The formation and active manipulation of magnetic-fieldinduced structures are very important in the physics of magnetic particle suspensions, and these suspensions are employed in numerous fields [1][2][3][4], such as magnetorheological fluids (MRFs) [5][6][7]. MRFs are smart materials that exhibit similar * Author to whom any correspondence should be addressed.…”