Multifunctional metamaterials for simultaneous sound absorption and flexural vibration isolation

• A metamaterial plate that can simultaneously absorb sound and isolate flexural vibration is proposed. • The frequency of the sound absorption peak and flexural wave bandgap can be tuned as desired. • The numerical and experimental demonstration for the sound absorption and flexural vibration isolation . Controlling the noise and vibration simultaneously in some engineering scenes is extremely essential to eliminate harmful effects on the humans and equipments. To overcome this challenge, a multifunctional metamaterial plate with both airborne sound absorbtion and flexural vibration isolation simultaneously is investigated theoretically, numerically, and experimentally. The plate consists of a host plate and a Helmholtz resonator, where Helmholtz resonance is used to absorb sound waves and its external solid domain plays as role of a local resonator to isolate the flexural vibrations. The theoretical models were established to characterize the mechanism of the sound absorption and vibration isolation . The experimental results demonstrated that the proposed metamaterial plate can achieve perfect sound absorption at 649 Hz and a flexural wave band gap at 289–470 Hz. Besides, although the sound absorption and vibration isolation functions are integrated in the same component, our theory identifies several critical geometrical parameters which can manipulate the absorption peak and the flexural wave bandgap, allowing us to design its frequency of multiple functions as desired. This work provides a promising solution for noise and vibration reduction in engineering.