Effects of Pore Shape Contour on Band Gaps of 2D Periodic Structures

We study contours of pore shape and investigate their effects on the band gaps of two-dimensional monolithic porous phononic metamaterials. As pore shape plays a significant role in the performance of metamaterials, previous studies considered up to 2nd coefficients of the Fourier series describing the pore shape. In our research, up to 6th shape coefficients are used to design the pore shapes to realize the changes in band gaps. We use both two-fold and four-fold symmetric unit cells in square lattices to capture the response and observe significant influences on the band gaps at different frequency levels due to the higher-order shape factors. These findings could lead us to new design of metamaterials with band gaps at desirable frequencies.