VIBRATION AND BUCKLING OF MULTILAYERED COMPOSITE BEAMS ACCORDING TO HIGHER ORDER DEFORMATION THEORIES

Natural frequencies and buckling stresses of laminated composite beams are analyzed by taking into account the complete effects of transverse shear and normal stresses and rotatory inertia. By using the method of power series expansion of displacement components, a set of fundamental dynamic equations of a one-dimensional higher order theory for laminated composite beams subjected to axial stress is derived through Hamiltonʹs principle. Several sets of truncated approximate theories are applied to solve the eigenvalue problems of a simply supported laminated composite beam. In order to ensure the accuracy of the present theory, convergence properties of the first seven natural frequencies are examined in detail. Numerical results are compared with those of the published existing theories and FEM solutions. The modal displacement and stress distributions in the depth direction are obtained and plotted in figures. The present global higher order approximate theories can predict the natural frequencies, buckling stresses and interlaminar stresses of multilayered composite beams as accurately as three-dimensional elasticity solutions.