As an intelligent material, magnetorheological fluid (MRF) is used in various applications, such as vibration dampers and automotive engine mounts. In order to study the influence of MRF composition parameters on vibration transfer characteristics, this paper proposes an MRF vibration transmission equivalent model based on the analysis of the interaction between carbonyl iron particles (CIPs) and carrier liquid, calculates the vibration transfer power flow level difference (PLD) of MRF with different composition parameters, and performs experimental verification. The results show that when only the particle diameter changes, the PLD peak increases with increasing particle diameter, and the PLD peak frequency shifts to lower frequencies. When the particle volume fraction gradually increases, and the remaining parameters are kept constant, the PLD peak increases first and then decreases, and the peak frequency shifts to high frequencies. When changing only the carrier liquid viscosity, the PLD peak decreases as the viscosity increases, while the peak frequency is shifted toward the high frequency. The MRF has a maximum frequency shift of 61.6Hz when the particle diameter, particle volume fraction, and carrier liquid viscosity are 8μm, 20% and 0.3 Pa·s, respectively. It is shown that adjusting the composition parameters can change the PLD and vibration suppression band of MRF, and using this feature can help improve the broadband vibration suppression performance of MR devices and the vibration suppression efficiency under specific working conditions, further expanding the application of MRF in the field of vibration control.

In this work, the theoretical and experimental study on vibration transmission in quasi-periodic impedance layered structures built by magnetorheological (MR) fluid is conducted. Based on the MR effect of MR fluid, the quasi-periodic layered structures formed by low and high impedance layers following Fibonacci, Thue-Morse and multiperiodic sequences are constructed, respectively. These different quasi-periodic patterns can be flexibly obtained by controlling the arrangement style and magnetic field strength of electromagnets outside the MR fluid. The vibration transfer model is established based on the transfer matrix method and the trends of vibration level difference with different parameters are analyzed. Furthermore, experiments are performed to estimate the vibration transmissivity of the proposed structures. It indicates that the developed quasi-periodic impedance layered structures can exhibit greater damping effect on vibrations by appropriately increasing the magnetic field strength and thickness ratio of low to high impedance layers. Moreover, there exist quasi-periodic impedance patterns whose attenuation effect on vibration is better than that of periodic pattern in the frequency range studied in this paper (20~200Hz). This means that the introducing of the particular quasi-periodicity increases the transmission loss of vibrations in a certain frequency range. This investigation is conducive to further expand the application of MR materials and quasi-periodic structures in the field of vibration control.