DIFFRACTION OF NORMAL-MODES IN COMPOSITE AND STEPPED ELASTIC WAVE-GUIDES

A method of calculating the diffraction of Lamb waves at the vertical junctions of elastic waveguides is proposed, the effectiveness of whic h is ensured by taking into account the nature of the singularity of t he solution at corner points. The property of the generalized orthogon ality of normal modes plays a key role. It enables the coefficients of the expansion of the wave field in the modes to be expressed in terms of the displacements and stresses along the junction line. Numerical results are presented which show how the transmission coefficients and the energy distribution depend on the height of the step and frequenc y for a stepped waveguide, attached to an undeformed substrate. (C) 19 98 Elsevier Science Ltd. All rights reserved.