SOME OBSERVATIONS ON THE MODELING OF LAMINATED COMPOSITE BEAMS WITH GENERAL LAY-UPS

In this paper the modeling of laminated beams has been considered by a systematic reduction of the constitutive relations of the three-dimensional anisotropic body. The basic equations of the beam theory here are those of the parabolic shear deformation theory. Numerical results for natural frequencies and the Euler buckling load have been presented using the present modeling of the constitutive relations and those of the conventional type modeling. It has been observed from the numerical results that the two approaches differ little in the case of cross-ply laminates but there exists a considerable difference (by a multiple factor of 3 in some cases) in the case of angle-ply laminates. The correctness of the present modeling has been further verified by modeling the same beam as a plate. It has been concluded that one should adopt the constitutive relations as given in this paper while modeling the laminated, especially angle-ply, composite beams.