Résumé
In this paper, guided ultrasonic wave propagation is analyzed in an elastic plate with sinusoidal surface corrugations. The corrugated area acts as a finite length grating which corresponds to a 1D phononic crystal (PC). The multiple-scales perturbation technique is used to derive coupled-mode equations describing the amplitudes of interacting modes. These equations are solved exactly for the two-point boundary-value problem of the PC. The study involved the coupling of the incident symmetric Lamb Wave S0 to the reflected antisymmetric Lamb wave A0. The influence of the depth of corrugation and length of the PC is studied. Theoretical results are compared with experimental measurements.