A utilitarian preparation method of magneto-rheological elastomers based on modified equivalent stiffness model

Abstract

Magnetorheological elastomers (MREs) are promising smart materials for structural vibration reduction applications due to their variable stiffness with applied magnetic fields. However, when preparing specific MREs for different vibration reduction applications, numerous preparation and testing experiments are generally used to obtain the qualitative relationship between the equivalent stiffness of MREs and the matrix modulus, the volume fraction and size of the magnetic particles, then repeated experiments are performed to finally prepare MREs that have target stiffness, which is time-consuming and inefficient. In this paper, based on the linear elasticity theory, Hooke’s law and chain-like microscopic mechanism, the analytical relationship between the equivalent stiffness of MREs and the matrix modulus, the volume fraction and size of magnetic particles is derived, thus establishing the modified equivalent stiffness model of MREs used for preparation. On this basis, the key preparation parameters, namely the matrix modulus, volume fraction and particle size of magnetic particles, can be directly calculated according to the target stiffness of MREs used in the specific applications, so as to prepare the corresponding samples. Taking the vibration reduction of large power equipment namely enclosed isolated-phased busbar (EIPB) as an example, and based on the calculated parameters, the MRE samples are prepared and tested by mechanical experiments. The results show that when the applied magnetic field strength changes from 0 to 200 mT, the equivalent stiffness of MREs increases from 167 to 312 kN/m, and the relative error is less than 5% when the applied magnetic field strength is above 50 mT. The experimental results show that the proposed equivalent stiffness model has high accuracy, and the preparation method based on the equivalent stiffness model is more practical and can improve the preparation efficiency of specific MREs. The most important contribution of this paper is the utilitarian preparation method, focusing on a theoretical material preparation method. This work has important practical values in the preparation method of MREs for specific applications.