A generalized element for the free vibration analysis of composite beams

A general finite element based on a first-order deformation theory is developed to study the free vibration characteristics of laminated composite beams. The formulation accounts for bi-axial bending as well as torsion. The required elastic constants are derived from a two-dimensional elasticity matrix. As many results are not available for bi-axial bending vibration of beams, the obtained numerical results are compared with those existing in the literature for the case of uni-axial bending. The predominating modes for the first eight frequencies for different fibre orientations are presented. The numerical results given explain the effects of shear deformation on various vibrational frequencies of angle ply laminates. The parametric study conducted brings out the influence of beam geometry and boundary conditions on natural frequencies. © 1994.