The Boundary Between the Concepts of Material and Structure in the Plate and Shell Theories for Laminated Media

Abstract

From the viewpoint of the mechanics of heterogeneous media each ply in laminates shall be considered to be a different material.

As a result, the analysis of the laminate structures should be made following three-dimensional models of heterogeneous bodies, the internal boundary conditions being incorporated in the interfaces.

On account of the high complexity involved in such a concept, ordinarily the analysis of laminated plates and shells follows two-dimensional models. The hypotheses of the theories behind such models in general allow us to establish constitutive equations that correlate generalized stresses and strains. Hence the laminate is implicitly dealt with as a hypothetical two-dimensional material

In the present research work the general consistence of this type of theories is discussed, particular emphasis being laid on their mutual relationships and on the universality of the constants that they foresee.