Development of MRE-based metamaterial with adjustable frequency bandgap for seismic vibration isolation

A seismic isolation system is an engineering method to prevent structures from the undesirable vibrations of earthquake. It involves using isolators, dampers, and bearings to decouple the superstructure from the ground during seismic waves by reducing the forces and accelerations transferred to the structure. The goal of this research is to investigate the tunable MRE-based metamaterial foundation for seismic vibration isolation. Meta- materials with adaptive and variable frequency band gaps are preferred because earthquakes have a wide range of frequencies. By varying the magnetic field intensity, a magnetorheological elastomer (MRE)-based metamaterial foundation can modify its Young's modulus and stiffness. The frequency band gap or frequency range of the MRE-based metamaterial foundation can be shifted by tunable material properties. Under the effect of a magnetic field, a uniaxial compression test was conducted to evaluate the Young's modulus of three types of MRE samples. Following the compression test, a series of numerical simulations in ABAQUS were carried out using a two-story framed building with RC and MRE-based metamaterial foundation. Three earthquake excitations are used: Bishop, Oroville, and Imperial Valley. The experimental results suggest that the magnetic field influences the MRE's Young's modulus. Similarly, numerical simulation studies indicate that the magnetic field influences the frequency band gap of the MRE-based metamaterial foundation. The FRF results of conventional RC foundation and MRE-based foundation are compared, highlighting the efficiency of MRE-based foundation in vibration control by reducing the seismic vibration of a structure by 68.5 %.