Fundamental Frequency Optimization of Angle-Ply Laminated Plates Using Elitist-Genetic Algorithm and Finite Strip Method

In the present paper, fundamental frequency optimization of symmetrically angle-ply laminated composite plates is studied using the combination of Elitist-Genetic algorithm (EGA) and finite strip method (FSM). The design variables are the number of layers, the fiber orientation angles, edge conditions and plate length/width ratios. The classical laminated plate theory (CLPT) is used to calculate the natural frequencies of laminated rectangular plates. To improve the speed of the optimization process, the elitist strategy is used in the Genetic algorithm. In the E-GA, the fittest individuals in the generation survive and are automatically reinserted in the next generation, right before the next selection process takes place and the fitness function is computed with a semi-analytical finite strip model developed originally on the basis of full energy method. In addition, from the computational economy point of view, combination of E-GA and FSM provides a much higher convergence and reduced the CPU time. To check the validity, the obtained results are also compared with some other stacking sequences.