2-D unstructured numerical simulation of acoustic Lamb and Scholte-Stonneley waves propagation. Influence of defects in plates

A numerical model for simulations of transient elastic waves in complex objects has been developed. The equations of motion are written in terms of stresses, displacements and displacement velocities for control volumes constructed about the nodes of a triangular unstructured grid. The latter conveniently supports various geometries with complex external and internal boundaries separating sub-domains of different elastic properties. Applied here to the problem of propagation of transient waves in immersed elastic plates, this method provides a new way of analyse of the mechanisms of creation and propagation of Lamb waves (A_n, S_n; 0 ⩽ n ⩽ 2) and the Scholte Stonneley surface wave (A). Influence of defects such as a soldered joint or a slit are also considered