Optimal design of hybrid composite structures exploring species conservation concept in genetic search

Abstract

Aiming to solve the optimal design of hybrid composite structures an approach based on Hierarchical Genetic Algorithm (HGA) and Species Conservation Technique (SCT) is proposed addressing the optimal stacking sequence and material topology as a multimodal optimization problem. More than applying similar concepts used in Parallel Genetic Algorithm (PGA), a hierarchical relationship between sub-populations is introduced together with an evolutionary philosophy based on the species conservation concept. A cooperation between elitist evolutionary strategies based on fitness at sub-population level and the species conservation concept is implemented. Using appropriate selection criteria for migration flows and adopting an age structure in the process of deletion of individuals then equilibrium between elitism and need for species conservation is reached. Results show that the procedure for species control is effectively able to allow multiple optimal solutions and guarantees the sub-population diversity. The identification of a high quality set of solutions will provide an insight of the space design suggesting alternative and innovative solutions for robust design optimization of composite structures.