Surface Effects in Elastic Surface Waves

Abstract

Surface or interface waves are often studied by simply matching two half media. Surface effects may involve changes in inertial (mass) or elastic properties. These are here treated as additional boundary conditions which modify the matching equations. The treatment includes extra surface forces in all possible directions, is based on the Surface Green function matching (SGFM) method and is developed in a way which applies equally to solids and to viscous fluids. Several problems concerning surfaces, interfaces and planar defects are discussed, as well as open questions concerning the connection between lattice dynamics models and their elastic limit. The formal analysis is extended to the case of layered media and the limit of infinitesimally small thickness of a layer is explicitly obtained and used to corroborate the above results.