Conditions admitting the existence of type 3 transonic states in stable anisotropic linear elastic media (Q687287)

We examine the possible existence of type 3 states in media of isotropic, hexagonal, trigonal, tetragonal and cubic symmetry. Only stable media of hexagonal and tetragonal symmetry admit type 3 states, and our analysis fully delineates the orientations and restrictions on the elastic stiffnesses associated with the existence of these states.