Scattering of Lamb waves at the edge of a semi-infinite plate embedded in water

An experimental study is presented of the scattering of Lamb waves at the end section of an elastic plane plate immersed in water. For antisymmetric modes as well as for symmetric ones, the amplitude of the radiated bulk wave in the water is recorded versus the angle of observation. In order to explain these patterns, a model is proposed that deals with the Lamb wave displacements inside the plate. The agreement between the theoretical and the experimental diagrams is quite good. The radiation pattern obtained for parameters corresponding to the crossing of two Lamb dispersion curves is also investigated.