On static analysis of finite repetitive structures by discrete Fourier transform

Functional solutions for the static response of beam- and plate-like repetitive lattice structures are obtained by discrete Fourier transform. The governing equation is set up as a single operator form with the physical stiffness operator acting as a convolution sum and containing a matrix kernel, which relates to the mechanical properties of the lattice. Boundary conditions do not affect the equation form, and are taken into account at a subsequent stage of the analysis. The technique of virtual load and substructure is proposed to formally close the repetitive lattice into a cyclic structure, and to assure the equivalence of responses of the modified cyclic and original repetitive lattices. A discrete periodic Green’s function is introduced for the modified structure, and the final displacement solutions are written as convolution sums over the Green’s function and the actual external and virtual loads. Several example problems illustrate the approach