Multiscale magneto-mechanical coupling of magnetorheological elastomer isolators

Due to their variable stiffness characteristics, magnetorheological elastomers (MREs) can be applied for seismic isolators in civil infrastructure systems. The lateral stiffness variation of MRE isolators is affected by the change of MRE shear stiffness. The natural frequency of the MRE-based isolation systems is related to the lateral stiffness of the MRE isolators with the range of lateral stiffness variation of MRE isolators serving as a critical objective to determine the shift ability of natural frequencies of the isolation systems. Here we develop a multiscale computational method to determine the magneto-mechanical coupling of MRE isolators. The field-dependent stiffness variation of the isolators is achieved with the consideration of combined magnetic field and deformation. Effects of MRE microstructural feature (e.g., particle concentrations in chains and between chains) and macroscopic geometry (e.g., thicknesses of MRE laminate and steel) on the magneto-mechanical responses of the isolators are specifically investigated, so as to guide the design of MRE-based isolating structures. The magnetic field and lateral stiffness of several MREbased isolator prototypes from experiments are obtained by finite element-based shear simulation. Simulation results are quantitatively compared with experimental data, verifying and validating the accuracy and applicability of the proposed method.