Momentless Design of Composite Structures with Variable Elastic Constants

In recognizing the increasing availability of various composite materials, this paper promotes a new approach to the design of the plate and shell structures. It is based on the loading and shape require ments of the structure to determine a particular composite whose constituents and their geometric arrangements are such that a certain design criterion will be satisfied. For the preliminary study of such an approach, a momentless criterion is adopted in the present paper for the design of axisymmetrically loaded shells of revolution. To maintain the shell in a momentless state, the general equation which governs the shape, loadings and the material properties of the shell, and the displacements equations have been derived. Applications to the pressure vessels with ellipsoidal bulkheads show that composite materials with variable elastic constants will be needed for constructing a momentless vessel. Numerical examples are presented to illustrate the proposed method of approach and provide as guidelines for the development of new composites.