Session: P1L

cylinders utilising elastic materials of cylindrical anisotropy. The formulation is based on linear three dimensional elasticity using an analytic form for the displacement field. A similar formulation has been used in the study of waves in plates and more recently, by the authors, in homogeneous cylinders. We have now developed the necessary formulas to apply it to cylinders in which the inhomogeneity in the elastic moduli and density is a function of the radial coordinate giving rise to functionally graded material (FGM) cylinders. The method incorporates the stress-free boundary conditions directly in the equations of motion by assuming position-dependent elastic constants and mass density. The problem is then reduced, as done for homogeneous structures, to a tractable eigenvalue problem allowing the dispersion curves and associated profiles to be easily calculated. All the conceptual and computational advantages obtained for plates are kept in the extension for cylindrical structures. Thanks to a developed software capable of dealing with a variety of inhomogeneous cylinders in an efficient and accurate manner, the technique is applied to analyse several inhomogeneous cylinders made up of a mixture of ceramic and metal and results are compared with those published earlier. The agreement is very good for both thin and thick cylinders which clearly illustrates the effectiveness of using the presented method to numerically model guided waves in inhomogeneous cylinders. Although results are shown only for isotropic materials, the method can deal with materials of cylindrical anisotropy but such results for FGM cylinders were not available in literature for comparison. To the authors’ knowledge, it is the first attempt to model guided waves in anisotropic inhomogeneous cylinder. Potential applications are in thermal-protection systems where the gradient law is chosen so as to better tailor the thermomechanical characteristics but also in acoustic fibers where the gradient law is chosen to confine the energy in the core of the fiber.