Dept. of Mech., Mater., and Aerospace Eng., Illinois Inst. of Technol., Chicago, IL 60616
Dimitrios A. Sotiropoulos
Tech. Univ. of Crete, Chania 73100, Greece
Reflection of elastic waves from the free surface of orthotropic incompressible materials is examined under plane strain conditions in a material symmetry plane. Use of the physically allowable energy flux vectors in conjunction with the propagation condition and the generalized Snell's law, yields formulas for the range of existence of the different types of reflected waves with respect to the two elastic parameters: the material orientation of the free surface and the angle of incidence. It is the consideration of the energy flux vectors that, in general, introduces the second elastic parameter and enlarges the range for the existence of either two homogeneous shear plane waves or one homogeneous and one supersonic surface wave. In the special case of transverse isotropy, the above formalas yield a homogeneous shear wave and a surface wave which diminishes when the angle of incidence is 45(degrees), the wave-number vector coincides with the energy flux vector, and there enters only one elastic parameter.