Forward models for surface wave prediction of material property profiles

Forward and inverse problems are intertwined. In order to qualitatively assess the existence of an inverse solution to the prediction of material property profiles we examine three forward problem approaches. These approaches are described and applied to two model material systems, a hardened steel gradient and a nickel copper nickel sandwich. The results suggest that a simple rule of mixture model should not be overlooked for material systems whose acoustic property profiles are monotonically slowly varying. More difficult profiles can be handled by the Thomson-Haskell matrix method