Non-linear elastic wave propagation in a planar waveguide

Full text: A theoretical model for finite amplitude guided wave propagation in weakly non-linear planar layered structures has been developed, based on a partial plane wave approach, in which the non-linearity is treated as a first-order perturbation. This model reveals many interesting features of the physics of the wave propagation and harmonic generation, and has been used to guide the experimental work. Measurements on an aluminium alloy sheet show the generation of harmonics of the propagating wave. At certain points in the Lamb wave spectrum, 'resonant' harmonics that grow in amplitude as they propagate down the plate have been observed