Composite Materials Research Progress

In: Composite Materials Research Progress ISBN: 1-60021-994-2
Editor: Lucas P. Durand, pp. 51-107 © 2008 Nova Science Publishers, Inc.
Chapter 2
OPTIMIZATION OF LAMINATED COMPOSITE
STRUCTURES: PROBLEMS, SOLUTION PROCEDURES
AND APPLICATIONS
Michaël Bruyneel
SAMTECH s.a., Liège Science Park
Rue des Chasseurs-ardennais 8, 4031 Angleur, Belgium
Abstract
In this chapter the optimal design of laminated composite structures is considered. A
review of the literature is proposed. It aims at giving a general overview of the problems that a
designer must face when he works with laminated composite structures and the specific
solutions that have been derived. Based on it and on the industrial needs an optimization
method specially devoted to composite structures is developed and presented. The related
solution procedure is general and reliable. It is based on fibers orientations and ply thicknesses
as design variables. It is used daily in an (European) industrial context for the design of
composite aircraft box structures located in the wings, the center wing box, and the vertical
and horizontal tail plane. This approach is based on sequential convex programming and
consists in replacing the original optimization problem by a sequence of approximated subproblems.
A very general and self adaptive approximation scheme is used. It can consider the
particular structure of the mechanical responses of composites, which can be of a different
nature when both fiber orientations and plies thickness are design variables. Several numerical
applications illustrate the efficiency of the proposed approach.
1. Introduction
According to their high stiffness and strength-to-weight ratios, composite materials are well
suited for high-tech aeronautics applications. A large amount of parameters is needed to
qualify a composite construction, e.g. the stacking sequence, the plies thickness and the fibers
orientations. It results that the use of optimization techniques is necessary, especially to tailor
the material to specific structural needs. The chapter will cover this subject and is divided in
three main parts.