Research on a mechanical model of magnetorheological fluid different diameter particles

In this paper, the chain structure of magnetorheological fluid (MRF) magnetic particles was studied and analyzed, the mechanical model of MRF with different diameter ferromagnetic particles was established, silicone oil-based MRF with different particle volume fractions was prepared, the shear properties of the MRF were tested, and the theoretical and experimental data were compared. The experimental results show that the shear stress is stable with the increase of shear strain rate under the action of the magnetic field, and it has a shear thinning effect. The shear stress increases linearly with the increase of particle volume fraction. The shear stress increases with the increase of magnetic induction intensity. After data analysis and in the case of control variables, the average error of improved theoretical data and experimental data is lower than that of previous theoretical data and experimental data, which verifies that the improved theory (mechanical model) has a certain accuracy.

Magnetorheological fluid based on amorphous Fe-Si-B alloy magnetic particles

Magnetorheological fluids (MRFs) based on amorphous Fe-Si-B alloy magnetic particles were prepared. The influence of annealing treatment on stability and rheological property of MRFs was investigated. The saturation magnetization ( Ms) of amorphous Fe-Si-B particles after annealing at 550°C is 131.5 emu/g, which is higher than that of amorphous Fe-Si-B particles without annealing. Moreover, the stability of MRF with annealed amorphous Fe-Si-B particles is better than that of MRF without annealed amorphous Fe-Si-B particles. Stearic acid at 3 wt% was added to the MRF2 to enhance the fluid stability to greater than 90%. In addition, the rheological properties demonstrate that the prepared amorphous particle MRF shows relatively strong magnetic responsiveness, especially when the magnetic field strength reaches 365 kA/m. As the magnetic field intensified, the yield stress increased dramatically and followed the Herschel-Bulkley model.

Self-adapting model for variable stiffness magnetorheological dampers

Variable stiffness magnetorheological fluid (MRF) dampers inherently have special nonlinear characteristics and complex structures. An accurate model describing the nonlinearity is the key for the damper to operate under variable conditions. This paper proposes a self-adapting model to characterize the variable stiffness MRF dampers through corresponding optimized algorithm. The experimental results verify the capability of the self-adapting of the model parameters. The model can describe the nonlinear characteristics of the variable stiffness MRF damper when conditions are changed. The proposed self-adaptive model improves the model accuracy which provide an approach for modeling complex dampers under variable working conditions.