Stochastic optimization of graphite-flax/epoxy hybrid laminated composite for maximum fundamental frequency and minimum cost

•Development of ecofriendly and lightweight engineering structures.•Natural fiber reinforced laminated composite design optimization.•Maximization of fundamental frequency while minimizing cost by stochastic optimization.•Interply hybrid graphite-glass/epoxy and graphite-flax/epoxy laminated composites. Ecological approach in automotive, aerospace and marine industries have stated that natural fibers (especially flax) can be used as alternative reinforcing materials to glass fibers because of their inherent good vibration and cost performances. In this regard, the present paper is an attempt to show the usage of flax fiber as an alternative to E-glass in interply hybrid composite structures in terms of fundamental frequency and cost. Stacking sequences design and optimization of laminated composites based on Differential Evolution (DE), Nelder Mead (NM) and Simulated Annealing (SA) algorithms are considered. The optimization problem is to find the number of high stiffness and less expensive laminates maximizing the fundamental frequency and minimizing the cost by multi objective optimization approach. The results show that the proposed optimum graphite-flax/epoxy interply composite structure give better than the result of graphite-glass/epoxy in terms of maximum fundamental frequency and minimum cost. It is also found that DE, NM and SA algorithms show comparable performance versus Ant Colony Optimization (ACO) for the same laminated structure design problems.