New theories for symmetric/unsymmetric composite and sandwich beams with C⁰ finite elements

Abstract

In this paper, a new set of higher order theories for the analysis of composite and sandwich beams by using C⁰ finite elements is presented. These theories incorporate the more realistic non-linear variation of displacements through the beam thickness, thus eliminating the use of shear correction coefficients. Discrete Lagrangian four-noded cubic element models having five, six and seven degrees of freedom per node are used. The computer program developed incorporates the realistic prediction of interlaminar stresses from equilibrium equations. By comparing the results obtained with the elasticity solution and the classical plate theory, it is shown that the present higher order theories give a much better approximation to the behaviour of thick to thin laminated composite beams. Numerical results for unsymmetric sandwich beams are also presented for future reference.