Layup optimization of laminated composite patches considering uncertainty of material properties

The layup of the maximum strength of laminated composite patch was optimized using genetic algorithm (GA). To calculate the three dimensional stress distribution of the composite patch efficiently, a stress function-based analytic method was applied. The principle of complementary virtual work was adopted to obtain the governing equations. In the process of GA, a repair strategy was used to satisfy given constraints. Moreover, multiple elitism was implemented to find multiple global optima effectively. A convex modeling method was applied to consider the bounded uncertainty of material properties. The results of the optimization were compared with those of optimization with nominal values. Since the GA optimization combined with convex modeling can practically offer the global optima considered the uncertainty of material properties, it is promising to use the proposed method as an efficient tool for analyzing and designing such aerospace composite structural components.