phonon crystals;  elastic wave band gap;  Planar wave unfolding

By discretizing the phonon crystal elements of the two-dimensional arbitrarily shaped scatterer, the numerical integration method is used to solve the integration problem in the solution of its structural function, so as to improve the existing plane wave algorithm, which can calculate the band structure of the two-dimensional arbitrary element structure square lattice phonon crystal. By comparing the band structure of phonon crystals with the regular element structure calculated by the traditional and improved plane wave algorithms in this paper, the correctness of the proposed algorithm is verified. The improved plane wave algorithm can be used to optimize the element structure of two-dimensional phonon crystals, so as to improve their bandgap characteristics.