Frequency optimization of laminated composite spherical shells

This paper deals with frequency optimization of symmetrically laminated angle-ply spherical shells. 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 and nine-node isoparametric finite element model are used for the finite element solution of the laminates. The modified feasible direction (MFD) method is used for the optimization routine. For this purpose, a program based on FORTRAN is used. Finally, the numerical analysis is carried out to investigate the effects of geometrical parameters and boundary conditions on the optimal designs, and the results are compared