ON THE OPTIMIZATION OF COMPOSITE LAMINATED PLATES

This paper deals with the optimum design of composite laminated plates . Both ply orientation angles and ply thicknesses of the composite pla te are used as design variables. The optimum design process is divided into two sublevels. In the first sublevel, the strain energy of the p late is minimized by changing the ply orientation angles while the ply thickness distributions remain unmodified. In the second sublevel, wi th the angle values obtained in the first sublevel, the optimum thickn ess distribution of each ply is obtained by minimizing the structural weight while satisfying stiffness and gauge constraints. The final opt imum design is achieved by iterating between these two sublevels. The stiffness analysis is performed by the finite element method in which a triangular element is used that is suitable for from thin to thick p lates and includes the transverse shear effects. All the derivative an alysis is performed analytically. The mathematical programming method called Constrained Variable Metric is used to solve the optimum proble m. An example is provided for a rectangular laminated plate with good results to show the effectiveness of the method.