Free Vibration of Composite Beams Using a Refined Shear Flexible Beam Element

A finite element model based on a higher-order shear deformation theory is developed to study the free vibration characteristics of laminated composite beams. The Poisson effect, which is often neglected in one-dimensional laminated beam analysis, is incorporated in the formulation of the beam constitutive equation. Also, the effects of in-plane inertia and rotary inertia are considered in the formulation of the mass matrix. Numerical results for symmetrically laminated composite beams are obtained as special cases and are compared with other exact solutions available in the literature. A variety of parametric studies are conducted to demonstrate the influence of beam geometry, Poisson effect, ply orientation, number of layers and boundary conditions on the frequencies and mode shapes of generally layered composite beams