BEHAVIOR OF LAMB WAVES AND MULTILAYERED RAYLEIGH-WAVES IN AN ANISOTROPIC PERIODICALLY MULTILAYERED MEDIUM - APPLICATION TO THE LONG-WAVE LENGTH DOMAIN

The aim of this paper is to study the behavior of leaky Lamb waves and what we termed multilayered ed Rayleigh waves in anisotropic periodic ally multilayered media and particularly in the long wave length domai n. The multilayered medium is first studied in its whole complexity an d dispersion curves for multilayered Rayleigh modes are drawn For Carb on/Epoxy composites. The displacement vector of such a wave is studied in detail. enabling the examination of the change of the nature of a mode which is the result of a Floquet wave becoming propagative again. In the long wavelength domain, the multilayered Lamb modes are identi cal for all the multilayered media which have the same layers in a sup erlayer, irrespective of the stacking order of the layers. However, th e stacking order of the layers in a period of the multilayered medium has an importance in the validity domain of homogenisation for multila yered Rayleigh mode. When the frequency tends towards zero, the veloci ty of the multilayered Rayleigh mode tends towards the velocity of the Rayleigh wave that is propagating in the corresponding homogenised me dium. The validity domain of homogenisation therefore depends on the n ature of the studied waves.