Study and optimization on band gap properties of petal-type acoustic metamaterial

The paper designed a petal-shaped carve beam structure (PCBS) inspired by the petal features, and its band gap properties and elastic wave propagation behavior are explored. The influence of the resonance block radius R and beam width t on the energy band structure of the PCBS is investigated separately. The research reveals that increase of the resonant block radius R leads to a wider the second band gap and higher fractional bandwidth (FB). Increase of the beam width t leads to a higher band gap frequency. The FB reaches up to 125% after parameter optimization. Subsequently, the band gap’s formation mechanism is explored using vibration mode, and it was found that the resonant block’s local resonance is the reason for the development of the wide-frequency band gap. Finally, the properties of elastic wave transmission within the PCBS are investigated. The consequence demonstrates the PCBS has remarkable band gap properties with wide frequency band gap occurs around 2972 and 16996 Hz with widths of 4887 and 5171 Hz, respectively, accompanied by an FB reaching 90.24%. The peak attenuation within the band gap reaches 350 dB. This highlights its ability for broad-frequency wave control and offers a theoretical reference for novel vibration reduction design.