Modal analysis of the thin-walled composite spoke of an umbrella-type deployable space antenna

The paper presents the solution of the problem of free vibrations of the composite spoke of a large-scale umbrella-type deployable space antenna. The spoke is modeled as the thin-walled orthotropic composite cantilever rod of circular cross section. The motion equations incorporate the effects of transverse shear strain and inertia of rotation of the rod’s cross section. The analytical solution is obtained and parametric analysis performed for various angles of the reinforcement orientation and length-to-diameter ratios. Using this solution, the optimum parameters of the composite spoke design are determined subject to constraints imposed on the natural frequencies.