INFLUENCE OF CURVATURE ON THE PROPAGATION PROPERTIES OF RAYLEIGH WAVES ON CURVED SURFACES OF ARBITRARY FORM
曲面曲率对Rayleigh波传播特性的影响

Surface waves possess the important practical property of propagating around a sufficiently smooth curved obstacle almost unhindered. This fact allows surface waves are applied to check industrial products of complicated shape while the usage of bulk waves give undesirable reflection that strongly distort the legitimate signals. Thus, the surface waves are commonly utilized to detect the surface cracks, surface hardness, thickness of the coatings and residual stress distribution etc. Meanwhile, the delay effect of surface wave propagation along curved surfaces can be applied do design delay lines in electro-acoustic devices. Properties of surface waves, mainly the Rayleigh waves, propagation along curved surfaces play important roles in seismology, acousto-electronics and other scientific fields. For the homogeneous isotropic linear elastic structures with curved surfaces of arbitrary form, the WKB method is applied to solve the motion differential equation of Rayleigh surface wave propagation along curved surfaces. Both the effects of the curvatures of curved surfaces which along and perpendicular to the propagation direction on the penetration property of waves are taken into account. The potential function solution of the wave equation obtained by our method indicate that the influence of the curvature perpendicular to the propagation direction of waves is not neglected in general case. The analytical expression of Rayleigh wave number or wave velocity vs. curvature of curved surfaces are obtained by setting the propagation properties of Rayleigh waves on plane surface as basis. Some basic characteristics of the Rayleigh surface wave propagation behavior along curved surfaces are described through theoretical analysis and numerical examples. The results obtained in our research also indicate the potential practical application of these properties in engineering.