This paper proposes a double-vibrator three-component pillared phononic crystal plate and theoretically studies the properties of vibration band gaps of this plate. The band structures and the displacement fields of the eigenmodes are calculated by the finite element method. Comparing the transmission power spectrums of the vibrations in the plate, the flexural vibration gap is proved more useful than the longitudinal vibration gap. The influence of the lattice constant, the height, and diameter of the pillars on the flexural vibration gaps are investigated. A supercell composed of the uni-vibrator and the double-vibrator unit cells is also investigated, and the analysis shows that the starting frequencies of the gaps in this supercell structure depend on the features of its pillars. This research can be used in the low frequency vibration insulation of plate structures.

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Lamb wave band gaps in a double-sided phononic plateUsing the finite element method, we theoretically study the vibration properties of a phononic crystal plate composed of a square array of composite cylindrical pillars on both sides of a thin homogeneous plate. The dispersion relations, the displacement fields of the eigenmodes, and the power transmission spectra are given to estimate the starting and cutoff frequency of the flexural vibration band gaps. We investigate the evolution of the flexural vibration band gaps in the doubleside phononic crystal plate, with the height and diameter of the pillars on both sides arranged from a symmetrical distribution to an asymmetrical distribution. Numerical results show that the enlargement of the bandwidth of flexural vibration band gaps in both symmetrical and asymmetrical double-side phononic crystal plates depends strongly on the rise of the cutoff frequency of the gaps. The two pillars with an asymmetrical heights or diameters divide the first flexural vibration band gap into two gaps. These propagation properties of flexural vibration in the double-side plate can be utilized to design low-frequency vibration insulation and band-pass filters. V C 2015 AIP Publishing LLC. [http://dx.