Synthesis of magnetorheological fluid and its application in a twin-tube valve mode automotive damper

The theoretical model for predicting the damping characteristics of magnetorheological dampers (MRDs) not only facilitates the optimization of MRD parameters, but also provides assistance for the theoretical design of MRDs. However, some existing models have limitations in fully characterizing the damping characteristics of MRDs. In this paper, the workingstageof MRDs was categorized into yield and pre-yield stages based on whether the internal magnetorheological fluid (MRF) attains the dynamic shear yield state or not, and the Herschel-Bulkley model with pre-yield viscosity(HBPV) and improved polynomial model (IPOL) were employed to respectively characterize the yield and pre-yield stages of MRDs. Subsequently, the HBPV-IPOL model was proposed to characterize the complete damping characteristics of MRDs in low-frequency vibration conditions, with considering the local loss effect of the fluid in the model. To accurately characterize the magnetic induction intensity in the MRD damping channel, employing the steady-state finite element method (FEM) for magnetic field analysis; on this basis, dividing the damping channel to investigate the variation trends of the magnetic induction intensity in different regions. Simultaneously, the zero-field region hypothesis was proposed to quantitatively consider the influence of minute magnetic induction intensity in the traditional zero-field regions on the damping characteristics of MRDs. Finally, integrating the impact trends of currents in different regions, and employing the HBPV model to determine the impact magnitude of each region within the damping channel on the damping characteristics of the MRD in the yield stage. In the pre-yield stage, Polynomial curves were fitted to experimental damping force-velocity curves, and the obtained polynomials were employed to predict the damping characteristics. Extensive experiments have been conducted on MRD samples to assess the predictive performance of the model on MRD damping characteristics under sinusoidal displacement excitation vibration conditions with different excitation currents, vibration frequencies and vibration amplitudes.

Section: Introductionmentioning

confidence: 99%

Dual-stage theoretical model of magnetorheological dampers and experimental verification

Lei,

Li,

Zhou

et al. 2024

“…The major disadvantage of MR fluid is there particle settling because of difference in densities in MR fluid constituents which reduces the performance and life of the MR fluid system [12][13][14][15][16][17]. With the intention of increasing the stability and performance of the MR fluid many researchers have proposed different techniques like adding additive, reducing the particle diameter, making the particles bidisperse, coating, increasing particle concentration and reducing the base fluid viscosity [18][19][20][21][22][23][24][25][26][27]. The essential parameter that decides the performance of any MR fluid system is sedimentation stability and yield stress.…”

Section: Introductionmentioning

confidence: 99%

Effect of reduced geometric dimensions on torque generation in two plate rotor magnetorheological brake with in-house magnetorheological fluid

K¹,

Kadam²,

Kumar³

et al. 2023

Self Cite

The present study is aimed to evaluate the torque generation capacity of a two plate rotor magnetorheological (MR) brake using in-house prepared MR fluid. The prepared MR fluids were studied for sedimentation rate at different temperatures and flow characterization at different currents and at specific temperatures. The yield stress of the fluid is explored through Herschel-Bulkley (HB) model. The results depict significant increase in sedimentation rate and decrease in yield stress with increase in temperature of the MR fluid. MR brake (model-1) is fabricated after finite element method magnetics (FEMM) exhibit magnetic field of approximately 0.145 T in the shear gap than other two models (model-2 and model-3) considered in this study. Characterization of the MR brake illustrates that there is an increase in torque with increasing current. Further tests have been carried out to identify the effect of sedimentation on torque generation at 52 °C after 15 hours of sedimentation. The results indicate 16 % reduction in the initial torque because of settling of particles. MR fluid and particles characterization illustrates that 322 °C and 400 °C are critical points in controlling the MR fluid input parameters.

“…MRF [19,20] is an intelligent controlled material composed of magnetic materials, base solution, and additives. The viscosity of MRF can be changed with the variation of an external magnetic field, and this change is reversible, continuous, and can respond to changes in the magnetic field within milliseconds [21][22][23][24]. One of the issues that hinders the development of MRF is the sedimentation of magnetic particles, and numerous scholars have made efforts to address this problem [25,26].…”

Section: Introductionmentioning

confidence: 99%

Research on rheological properties and phenomenological theory-based constitutive model of magnetorheological shear thickening fluids

Zhao,

Wang,

Yuan

et al. 2023

This paper investigates the rheological properties of magnetorheological shear thickening fluid (MRSTF) and proposes a phenomenological theory-based constitutive model. Multiple samples with varying mass fractions and particle sizes were prepared. Then, the rheological properties were experimentally studied, including the effects of silicon particle size and concentration, carbonyl iron powder concentration and magnetic field on rheological properties. Next, the sedimentation stability experiment was also carried out by the static observation method. Finally, based on phenomenological theory, a constitutive model called the M-S model was derived through geometric transformation of shear stress curves. The results show that there is an inhibitory relationship between magnetorheological and shear thickening effect, and the correlation between composition and rheological properties was established, which can provide guidance for preparation of MRSTF with required properties. It also shows that the MRSTF under specific preparation scheme could effectively avoid sedimentation, and its performance is clearly superior to traditional materials in terms of sedimentation resistance and damping adjustment. The accuracy and universality of the proposed model are fully verified by fitting shear stress curves and calculating the goodness of fit values. All these investigations can offer an effective guidance for further study of MRSTF in controllable damping equipment development.