Effect of Fiber Angle on Out-of-plane and In-plane Natural Frequencies of Laminated Composite Beams

Out-of-plane and in-plane free vibrations of angle-ply and cross-ply laminated composite beams with different boundary conditions are studied. The effect of fiber angle on out-of-plane bending, torsional, in-plane bending, and axial natural frequencies are investigated separately. The beam is modeled and analyzed by the finite element method (FEM). The finite element software package ANSYS is used to perform the numerical analyses using an eight-node layered shell element. The rotary inertia and shear deformation effects are taken into account. The method of solution is validated by comparing numerical results with those available in the literature. It has been shown that, by choosing angle-ply lamination instead of cross-ply, torsional, in-plane bending and axial natural frequencies can be increased by approximately 40%.