Frequency optimization of laminated composite annular sector plates

This paper deals with frequency optimization of symmetrically laminated angle-ply annular sector plates. The design objective is the maximization of the fundamental frequency and the design variable is the fiber orientation in the layers. The first order shear deformation theory is used for the finite element solution of laminates. Nine-node Lagrangian rectangular plate element which have five degrees of freedom per node is used for the finite element solution of the laminated annular sector plates. The modified feasible direction method is used for the optimization routine. For this purpose, a program based on FORTRAN is used. The numerical analysis is carried out to investigate the effects of annularity, boundary conditions and sector angle on the optimal designs and the results are shown in tabular and graphical forms. Finally, the obtained results are compared. It can be shown that the parameters have a key role on the optimum design of laminated annular sector plates.