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 com posite beams. The formulation accounts for bi-axial bending as well as torsion. The required elastic constants are derived from a two-dimens ional elasticity matrix. As many results are not available for bi-axia l bending vibration of beams, the obtained numerical results are compa red with those existing in the literature for the case of uni-axial be nding. The predominating modes for the first eight frequencies for dif ferent fibre orientations are presented. The numerical results given e xplain the effects of shear deformation on various vibrational frequen cies of angle ply laminates. The parametric study conducted brings out the influence of beam geometry and boundary conditions on natural fre quencies.