Composite laminate stiffnesses and their sensitivities.

Abstract

The great number of possible stacking order to from laminates suggests to apply optimization, more frequently than usual, in the design of structures madeof composite materials. One of the columns upon which optimization of structures is built is the mathematical search procedures for locating a minimum ( or maximum ) of a constrained function. Efficient algorithms will require the evaluation of derivatives of the object function as well as of the constraints. In that context the sensitivities of laminate stiffness matrices may be required. In order to meet such a requirement the derivatives with respect to both ply thicknesses and ply angles, of laminate stiffnesses, including transverse shear stiffness, will be presented in this report.