Aircraft Composite Skin Stacking Sequence Generation Using Genetic Algorithms

Composites structures are widely used both in military and commercial aircraft industries. Design of tapered composite skins is quite laborious and time consuming. Optimization of these composite skins is essential for realizing the full benefits offered by composites. Composite skins are optimized in two stages. In the first stage, thicknesses of various zones of composite skin along with the percentage of fiber orientations is computed using gradient based algorithms. In the second stage, the stacking sequence generation is performed mostly using knowledge based engineering approaches using rules and heuristics. The stacking sequence generation is a combinatorial problem and is quite complex. Such combinatorial problems can be solved elegantly by genetic algorithms. The available genetic algorithm based stacking sequence approaches are mostly theoretical and are demonstrated mainly as research and academic problem for laminates of constant thickness with few constraints. In this paper a genetic algorithm based approach for stacking sequence generation of tapered composite skins with multiple zones is presented. This approach is scalable and can solve large size composite skin generation problems with reasonably good number of constraints. The paper also demonstrates the usefulness of the current approach by solving few large scale stacking sequence generation problems in real life aircraft industry.