Dissertation

Efficient optimization of laminated composites

Bloomfield, Mark William

2010

Overview

Currently, there are few computationally efficient optimization tools that provide detailed structural analysis for multi-part laminated composite structures. A two-level optimization approach is detailed and used to determine the stacking sequences of composite plates of minimum mass. At the first level, lamination parameters and plate thickness are used to minimize the structural mass subject to buckling, strength (allowable laminate strain) and lamination parameter (feasible region) constraints. A general method is presented to determine the set of constraints on the feasible region of lamination parameters for any finite set of ply orientations. The output of the first level is the minimum thickness. At the second level, ply orientations and a discrete optimizer are used to determine a laminate stacking sequence of that thickness which satisfies the set of design constraints. Formally, this is a constraint satisfaction problem. To solve the second level problem, a number of metaheuristic techniques are considered including an ant colony and particle swarm approach. Motivated by the analysis, three new solutions to the second level are presented. Additionally, using an expanded set of ply orientations (and a multi-level approach) it is demonstrated that mass savings can be achieved. Furthermore, the presented algorithms lead to efficiency savings in comparison with methods detailed in the literature. Consequently, this thesis presents an efficient and reliable approach to laminated composite optimization.

• Publisher: ProQuest Dissertations & Theses
• Subject: Aerospace engineering