LONG NONLINEAR STRAIN WAVES IN LAYERED ELASTIC HALF-SPACE

Elastic strain wave propagation in a thin non-linearly elastic layer s uperimposed on non-linearly elastic half-space is studied. Two layer-h alf-space contact models are considered. It is found that the Benjamin -One equation can be derived for description of longitudinal non-linea r strain waves, when the contact between the layer and the half-space is provided only by means of the normal stresses and displacements. Wh en the full contact problem is considered the more complicated integro -differential equation is derived. It is found that long non-linear pe riodical and solitary strain waves as well as envelope waves may exist in the first case, while only envelope wave solutions are found to th e full contact problem. Linear wave analysis shows that the Korteveg-d e Vries equation, often usable, is unlikely to be an adequate model fo r longitudinal surface strain waves. Application of the results obtain ed to experiments devoted to superconductivity threshold control in th in metal films as well as to generation of acoustic solitons in layere d half-space is discussed.