Free Vibration for Twisted Thin Conical Shell Panels

A numerical method for analyzing free vibrations of twisted thin conical shell panels is presented based on the Rayleight-Ritz procedure. To this end, exact strain-displacement relationships are derived by employing the thin shell theory and the principle of virtual work for free vibrations is formulated. Algebraic polynomials are used as assumed displacement functions in the analysis. Frequency parameters are analyzed for typical conical shell panels and effects of variation of the curvature of the shell and of pretwist on them are discussed. Resonance frequencies and modes of vibration obtained experimentally are compared with analytical ones. The agreement between them is found to be quite good.