Low‐Frequency Bandgap Optimization and Vibration Control of a Novel Phononic Crystal Plate

Based on the principles of localized resonance and finite element analysis, this paper proposes several novel acoustic metamaterial thin plates. These structures undergo numerical analysis and optimization, with the optimized configuration achieving a minimum onset frequency of 143.2 Hz, thereby fulfilling the objective of low‐frequency vibration damping and noise reduction. By analyzing the mode shapes of the structure at different frequencies, the opening mechanism of the low‐frequency bandgap is revealed. This phenomenon primarily results from rotational resonance of the scatterers, coupled with displacement resonance and localized resonance of the elastic plate. The accuracy of the bandgap of the structure can be proven by performing a transfer characterization of the structure, which shows a minimum transmission coefficient of −177.5, corresponding to a frequency of 322 Hz. Subsequently, analyzing the displacement contour plots of the structure under different excitation frequencies provides a clear visual representation of the variations in the structure's ability to suppress elastic wave propagation. Observations from group velocity and phase velocity images reveal that frequency variations exert a significant influence on the propagation direction, propagation velocity, and energy transfer of elastic waves within the structure. The thin‐plate structure proposed in this paper holds significant practical application potential for suppressing low‐frequency noise and vibration in real‐world engineering scenarios.