Invariant Based Design of Laminated Composite Materials

"A strategy for the design of laminated composite materials and sandwich structures based on the invariant properties of constituent materials and invariant properties of design goals is proposed. The use of first order invariants establishes thefeasibility of designs and separates linear from nonlinear design variables. The invariant "length" of second and fourth order tensors is proposed as a suitable criterion for finding layup angles as a minimization problem. Examples of the in-planestiffness of a laminate and the bending stiffness of a sandwich panel are given for illustration.This proposal is NOT about methods of analysis. This proposal is about the DESIGN of laminated materials. The technology will be commercialized as a MathematicaTM package and as a design module in a commercial finite element program. The fundamentalbenefit is the elimination of iterative/random walk design practices with the establishment of a sound strategy."