Research on bandgap optimization of aperiodic magnetorheological elastomer metamaterial sandwich beam based on genetic algorithm

In recent years, local resonant metamaterial structures with tunable bandgap characteristics have attracted increasing interest and attention from researchers. In order to achieve the widest local resonant bandgap, an offline-online combined optimization method for the bandgap of the aperiodic magnetorheological elastomer (MRE) metamaterial sandwich beam (AMREMSB) based on a genetic algorithm and the spectral element method was proposed in this study. The offline optimization of the distributions of the coil resonator positions and the MRE stiffness values was achieved by the genetic algorithm, with the objective function of maximizing the bandwidth obtained by the spectral element method. The AMREMSB with the solved optimal position parameters was then prototyped. Furthermore, the online optimization of the bandgap was achieved by regulating the currents of the coils in real time. Theoretical, simulated, and experimental results show the same qualitative trend that the optimized AMREMSB achieves a broader bandgap than the periodic counterpart. Experimentally, bandwidth improvements of 7.7 Hz and 7.8 Hz are observed at 0.0 A and 1.0 A, respectively. These findings indicate the potential of the proposed optimization method for widening the bandgap in MRE metamaterial beams.