On the stability of surface acoustic pulse trains in coated elastic media

Coating a planar surface of a homogeneous elastic halfspace by a thin film gives rise to dispersion of Rayleigh waves that, together with the second-o rder nonlinearity of the substrate or surface nonlinearities, leads to the existence of surface acoustic solitary pulses. Their shapes are computed an d their stability with respect to small changes of their initial conditions and partly to collisions with each other is analyzed numerically. The exis tence of gap solitary waves in the case of a periodically structured film i s demonstrated, and periodic solitary pulse train solutions on a small osci llatory background are found. Their stability is investigated by means of a Floquet analysis. (C) 2001 Elsevier Science B.V. All rights reserved.