Axisymmetric Wave Propagation in Functionally Grade Cylinder with Isotropic Concentric Layers

Abstract—: The axisymmetric wave propagation is investigated in coaxially layered isotropic functionally graded cylinders with different mass and stiffness properties of the layers. Exact solutions of the governing equations of the wave propagation in the cylinders exist only for isotropic, transversely isotropic and piezoelectric transversely isotropic cylinders. In the case of the functionally graded cylinders exact solutions are not known. The authors developed a method of exact solution of the problem, which is based on matching of continuity and boundary conditions on junctions of the layers. The continuity and boundary conditions are formulated in terms of exact solutions for displacements and stresses in the layers obtained in Bessel functions. The spectral diagrams of the dispersion curves of frequencies versus wave numbers are plotted for both propagating and evanescent waves and graphs of the phase and group velocities are obtained from these diagrams.