Frequency analysis of a heterogeneous perforated panel using a super-element formulation

Heterogeneous perforated panels represent a wide class of structural elements with holes where perforations and matrix are of dissimilar materials e.g. metallic member of a perforated hybrid joint with resin-fillings. There is a variety of objectives for introducing holes e.g. weight saving or mechanical interlock. Where there is a regular pattern to the arrangement of holes the perforated element can be assimilated to a lattice. In the present study, numerical analysis has been conducted on investigating the shock frequency filtering phenomenon encountered in two-dimensional (2D) lattice structures. A super-element of the primitive cell (unit cell) of the lattice has been formulated and applied in conjunction with the Floquet–Bloch's principle to study the shock response characteristics. Plane wave propagation is investigated by constructing the first Brillouin zone of the primitive cell in associated Fourier space (k-space). The frequency characteristics are presented in the band structure diagram. The study emphasizes the existence of frequency pass and stop bands and the extent of this phenomenon. The frequency filtering effects of the heterogeneous perforated 2D lattice has shown its potential value to improve the structural performance of perforated hybrid joints subjected to dynamic loads.