An approach to the dynamics of modular repetitive structures

The dynamics of modular structures is approached in this paper by means of the discrete Fourier transform. This method, applied to a structure with N bays and ring type boundary conditions, leads to N uncoupled systems of the size of a single bay. For other boundary conditions, it leads to a “spectrally resolved” eigenproblem, that is a form whose dominant terms in each field of frequency are evidenced. Approximate reduced models in narrow frequency fields can therefore be generated by using the “spectral condensation” technique. The method can be applied with general boundary conditions, but the present paper deals mostly with the “clamped edges” boundary condition and shows that numerical advantages can be obtained, particularly for the large space structures.