NONLINEAR DARK SOLITARY SH WAVES IN A HETEROGENEOUS LAYER

. In this study, we consider the nonlinear propagation of shear horizontal (SH) waves in a layer of finite thickness. The materials of the layer are assumed to be heterogeneous, isotropic, and generalized neo-Hookean. We assume that heterogeneity varies only with the thickness and we choose hyperbolic functions for heterogeneity type. We also assume that the traction is free on the upper surface of the layer. Furthermore, the lower boundary is rigidly fixed. Using a perturbation method and keeping the balance of the nonlinearity and the dispersion in the analysis, we show that the self-modulation of nonlinear SH waves can be given by the nonlinear Schr¨odinger (NLS) equation. Using well known solutions of NLS equation, we find that the dark solitary SH waves can exist depending on the nonlinear constitution of the layer. Consequently, the effects of the heterogeneity and the nonlinearity on the deformation field are considered for these waves.