Stacking sequence of a laminated cylindrical shell is optimized based on natural frequency. In the optimization problem, it is desired to have the maximum possible natural frequency. Laminated thickness is fixed and orientations are changed in a set of angles. A laminated cylindrical shell is considered anisotropic with finite length and simply supported edges. Free-vibration analysis is based on fully three-dimensional elasticity equations. The highly coupled partial differential equations are reduced to ordinary differential equations with variable coefficients by means of trigonometric function expansion in the axial dimension. The resulting differential equations are solved exactly. In this solution, the continuity conditions between any two layers are satisfied. A genetic algorithm is devised for designing composite laminates composed of only one material. The genetic algorithm procedure, referred to as GA-I, will be used for maximization of the lowest natural frequency of a laminated cylindrical shell with strength and ply contiguity constraints. Results are presented for stacking sequence optimization of three- and five-layer cylindrical shells.
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