Multiple flexural-wave attenuation zones of periodic slabs with cross-like holes on an arbitrary oblique lattice: Numerical and experimental investigation

The exploration for large and low frequency attenuation zones is one of the principal problems probed in phononic materials and structures. The flexural-wave attenuation zone properties of periodically perforated slabs with cross-like holes were investigated using ANSYS finite element software to obtain flexural dispersion curves conveniently and individually. The influence of geometric parameters, including hole shape and plate thickness, on attenuation zones was investigated. Unlike conventional phononic attenuation zone designs, typical cells with an arbitrary oblique lattice were examined. The dynamic responses of the finite periodic slabs using several designed cells were analysed numerically and experimentally under harmonic excitation conditions. The results showed that periodic slabs with cross-like holes on an oblique lattice can generate lower and multiple attenuation zones compared to square, circular, and diamond-shaped holes. The vibration modes at the attenuation zone edges were calculated and analysed to illustrate the zones' generation mechanism. The attenuation ranges obtained numerically were generally consistent with those of the experiment. This research showed that attenuation zones of periodically perforated slabs may have potential applications in acoustic and vibration screens.