THE EFFECTS OF TRANSVERSE SHEARING AND ANISOTROPY ON VIBRATION FREQUENCIES OF LAMINATED CYLINDERS

Natural vibration frequencies of orthotropic and anisotropic simply supported circular cylinders are predicted by using a higher order transverse shear deformation theory. A comparison of natural vibration frequencies of laminated cylinders predicted by first order transverse shear deformation theory and the higher order theory indicates that an additional allowance for transverse shear deformation has a negligible effect on the predicted natural vibration frequencies associated with long wavelengths, but significantly reduces the natural vibration frequencies associated with short wavelengths. A parametric study of the effects of ply orientation on the natural vibration frequencies of laminated cylinders indicates that while stacking sequence affects natural vibration frequencies, cylinder geometry and mode shape are more important in accurately predicting transverse shear deformation effects. Transverse shearing effects are less important in predicting natural vibration frequencies associated with long wavelengths than in predicting axial compressive buckling loads. The effects of anisotropy are more important than the effects of transverse shear deformation for most strongly anisotropic laminated cylinders in predicting natural vibration frequencies. However, transverse shear deformation effects are important in predicting natural vibration frequencies associated with short wavelengths of thick-walled laminated cylinders. Neglecting either anisotropic effects or transverse-shear deformation effects leads to non-conservative errors in predicted natural vibration frequencies. © 1990.