Research and Application of Vibration and Noise Reduction Local Resonance Metamaterial Plate

Locally resonant metamaterials (LRM) with structural stop band behavior can strongly increase the performance of vibration attenuation and sound transmission in a targeted frequency range. This work proposes an LRM plate with a folded beam structure to generate excellent property. The LRM plate is formed by a periodic arrangement of folded beam resonators, the LRM plate has the characteristics of broadband, low-frequency bandgap, light-weight, easy processing and can be well integrated into structures that require vibration and noise reduction. Firstly, theoretical and numerical researches are carried out to obtain the dispersion relation and the bandgap of the folded beam LRM plate utilizing both the plane wave expansion (PWE) method and the finite element method (FEM). Additionally, the dynamic properties of the LRM plate are acquired applying FEM to evaluate its wave attenuation ability within the bandgap. Lastly, the folded beam LRM is used to address the noise issue of the refrigerator in practical engineering, and the radiated sound power level (RSPL) of a refrigerator compressor during normal operation was reduced by about 10db within the designed bandgap range.