Investigation of the Effect of Geodesic and Semi-geodesic Winding on the Vibration Characteristics of Variable Stiffness Filament Wound Shells of Revolution

Abstract

Vibration characteristics of variable stiffness filament wound composite shells of revolution are investigated utilizing a numerical integration based solution method that is developed. Filaments are assumed to be placed along the geodesic and semi-geodesic fiber paths on the surface of the shell of revolution resulting in the variation of the stiffness coefficients and the thickness of the shell wall along the axis of the composite shell of revolution with general meridional curvature. For geodesic and semi-geodesic winding, relations giving the meridional variation of the winding angle and thickness are derived for truncated conical and spherical shells of revolution which are studied as the sample shell geometries. The effect of constant preset friction, applied during the winding process, on the stiffness and vibration characteristics of filament wound composite shells of revolution is studied in depth. In the most general case, multi-segment numerical integration technique is extended to the solution of the free vibration problem of composite shells of revolution which are wound along the semi-geodesic fiber paths counting on the preset friction used during the winding process. The effect of initial winding angle and the starting edge of the winding operation on the variation of the thickness, stiffness coefficients and free vibration characteristics of filament wound shells of revolution are investigated. Case studies are also performed on the comparison of the frequencies calculated by incorporating the actual variation of the winding angle and thickness, and the frequencies calculated based on constant winding angle and thickness which are taken as average and mid meridian values.

Non-Geodesic Trajectories for Filament Wound Composite Truncated Conical Domes

“…Filament wound conical shells are being widely used in the aerospace and commercial industries, such as pressure vessels, pipes, nozzles, and lattice structures. In the past decades, the design and analysis for filament-wound conical shells have been developed in a variety of facets [1][2][3]. However, previous work concentrated mostly on the use of geodesics as winding trajectories; the design freedom of this class of fiber patterns is severely limited because once the initial conditions of fiber position and orientation have been fixed, the entire fiber trajectory and winding parameters are solely determined [4,5].…”