THE USAGE OF STANDARD FINITE-ELEMENT CODES FOR COMPUTATION OF DISPERSION-RELATIONS IN MATERIALS WITH PERIODIC MICROSTRUCTURE

A method with which standard finite element programs can be used to co mpute dispersion relations in periodic composites is proposed. The met hod is applied to two composite microstructures: a two-phase laminate and a fiber composite. The dispersion relations computed for the lamin ate are compared with a known analytical solution and the agreement is very good. The dispersion relations computed for the fibrous composit e are compared with an existing approximate model and experimental res ults from the literature. The agreement between the approximate model, the experiments, and the computations is very good in the wave guide case and satisfactory for the wave reflect case. (C) 1997 Acoustical S ociety of America. [S0001-4966(97)04310-5] PACS numbers: 43.20.Jr, 43. 20.Gp, 43.20.Mv, 43.35.Cg [JEG].