THE EFFECT OF SHEAR ON THE PROPAGATION OF ELASTIC SURFACE-WAVES

The propagation of surface waves on a half-space of a pre-stressed inc ompressible elastic material is discussed. In contrast to previous stu dies, in which the pre-stress is associated with a pure homogeneous st rain with one principal axis normal to the surface of the half-space, this paper examines the influence of an underlying deformation which c orresponds to a homogeneous simple shear, so that no principal axis of the deformation is along the surface normal. For a particular class o f strain-energy functions an explicit secular equation for the wavespe ed is obtained and then analysed to provide necessary and sufficient c onditions for the existence and uniqueness of surface waves and quasi- static deformations. Numerical calculations are used to illustrate the dependence of the results on the amount of shear and on the hydrostat ic stress.