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Abstract A new design method of light phononic crystal cladding structure is proposed based on the local resonance mechanism. With the help of the finite element method, the energy band structure and eigenmodes of a new type of phononic crystal are calculated. When the total notch degree of the cladding is fixed, the influence of the number and location of different cladding notches on the cut-off frequency of the first complete band gap is analyzed. Two new phononic crystal models, line connection and point connection, are designed to connect the cladding and the scatterer, and the first complete band gap with an initial frequency of 37.4Hz and 19.0Hz are obtained respectively. The eigenmodes of scatterers at the initial frequency of the first complete band gap are analyzed, and the generation mechanism of the very low initial frequency of the first complete band gap of the new phononic crystal is revealed. Furthermore, it is compared with the traditional method of reducing the initial frequency of the first complete band gap by increasing the mass of the scatterer. The results show that when the total notch degree of the cladding is fixed, a wider first complete band gap can be obtained by using the cladding arrangement with more notches and farther away from the connecting short plate. The proposed cladding and scatterer line connected and point connected phononic crystals not only obtain a very low first complete band gap initial frequency, but also significantly reduce the phononic crystal weight, breaking through the limitation of traditional phononic crystals to reduce the first complete band gap initial frequency by increasing the scatterer mass, It provides a reference for the research and design of light phononic crystals to obtain very low local resonant band gap initial frequency.
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Received: 14 April 2022
Published: 28 October 2022
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2022, Vol. 43 
