Vibrations of Composite Noncircular Cylindrical Shells

Abstract

The free vibrational characteristics of composite noncircular cylindrical shells are investigated in this paper. The shells are composed of layered media of different material properties. The thickness of each layer is considered to be constant. First order composite shell theory, which includes the effects of shear deformation and rotary inertia, is used in the formulation. A combination of Bezier functions and beam functions is used to describe the displacement fields along the circumference and longitudinal directions, respectively, of the shell surface. The shell is modelled using a number of curved cylindrical panels. Displacement (C0 ), slope (C1 ) and curvature (C2 ) continuities between the panels are enforced by proper blending of the Bezier curves. Numerical results are included for a circular sandwich shell and a two-layer cross-ply oval cylinder that provide excellent agreement with those from the literature. The natural frequencies of clamped oval sandwich cylinders made of stiff outer layers and light middle layer are also presented.