HIGHER ORDER CONTINUUM MODEL FOR LAMINATED COMPOSITES

The paper deals with the laminated composites consisted of two different isotropic materials.With the displacements and their derivatives and stress vectors at the interfaces,the displacement in a layer is expanded.For such expansion the continuity conditions of displacement and stress at interfaces are satisfied automatically.By applying a variational theorem without constraint,Eider equations at interfaces are derived,from which the field equations of a higher order continuum model are obtained.Two extreme cases long wave and short wave approximations are considered.The calculated results for dispersion curve including the past band and stop band show a good agreement with the existing theory.