Experimental verification of the theory of multilayered Rayleigh waves

Abstract

A phenomenon which has been termed ''multilayered Rayleigh modes'' has been presented in previous papers. This study aims to prove experimentally the existence of these waves in anisotropic periodically multilayered media. These modes result from a combination of Floquet waves which propagate in a periodically multilayered medium when all the Floquet waves are inhomogeneous. The experimental verification was done using an acousto-optic technique and a measurement of the reflected field, which was obtained with a hydrophone measurement system, on a carbon/epoxy composite plate. The experimental and calculated dispersion curves of the multilayered Rayleigh modes were then drawn. The coincidence of the curves was found quite good, thus confirming our theory. However, two modes were found by the acousto-optic technique not to fit into the theory. One experimentally detected mode was found to correspond to the Lamb mode of the plate and the other was not experimentally detected by the acousto-optic technique. Measurement of the reflected field for this mode, which was obtained with a hydrophone measurement system, and its comparison with the predicted reflected field make it possible to verify the existence of the mode. The combination of both experiments permit a good coincidence to be found.

On Propagation Problems of New Surface Wave in Cubic Piezoelectromagnetics

“…Also, it was recently stated that phonon-polaritons in a form of a band-like structure can exist in piezomagnetic superlattices (PMSL) with periodically up and down polarized domain structures [41] in which the piezomagnetic coefficients are periodically modulated. Also, some theoretical approaches exist which use material constants with real and imaginary parts (complex numbers) to describe wave propagation in multi-layered structures [42]. Some works concerning the investigations of different metamaterials can be also found in Refs.…”

“…Some works concerning the investigations of different metamaterials can be also found in Refs. [43,44]. It is noted that Ref.…”

“…It is noted that Ref. [44] deals with three-dimensional bulk metamaterials. Therefore, it is thought that SH-BAWs and SH-SAWs can be investigated in bulk metamaterials.…”