Influence of the Plies Orientation on the Rigidity of the Laminated Composites

The overall properties of a laminated composite structure depend on design thereof, i.e., they depend on the thickness, on the orientation and the material of each ply in the stacking sequence, that is why optimization tools are used to assist decision making and designing structures with optimized properties. In this study, the design variables are only the plies orientation because the plies number, the material and the thickness are already selected. This problem will be treated as an optimization problem under constraints, whose objective function is the modulus of transverse stiffness of laminated composite to maximize, and the optimization variables are the plies orientation. The Monte Carlo method is applied as a constrained stochastic optimization, based on stratification parameters for the determination of optimal fiber orientations laminate structures to find the maximum longitudinal modulus of rigidity (Ex). Validation results of this approach have been compared with the results of Girard [4] who has used a genetic algorithm to optimize laminates by using equations of the classical theory of laminates and, by referring to the results of Luersen [3].