INTERFACIAL AND SURFACE-WAVES IN PRE-STRAINED ISOTROPIC ELASTIC MEDIA

Necessary and sufficient conditions for the existence of a small-ampli tude wave on the plane interface between two isotropic elastic bodies are derived and discussed. The bodies are assumed to have received hom ogeneous triaxial strains on common axes, one of which is normal to th e interface, before being rigidly bonded. They are composed of differe nt restricted Hadamard or neo-Hookean materials (respectively compress ible and incompressible), or incompressible isotropic elastic material s without restriction on the strain energy. In the latter case the wav e is required to travel along a principal axis of stretch. It is prove d that an interfacial wave is unique whenever it exists. Parallel resu lts for surface waves are obtained by releasing the bond, removing one constituent and taking the boundary of the remaining body to be free of incremental traction.