The minimum-weight design of compressively loaded composite plates
and composite stiffened panels under constrained Postbuckling strength is addressed
herein. A nonlinear finite element code, COSAP (COmposite Structural Analysis
Program) was applied to analyze the buckling and postbuckling behaviour. As an
optimization technique, a modified Genetic Algorithm was used to find the optimum
points. The parallel computing scheme was implemented with MPI (Message Passing
Interface) library and realized in a parallel-computing supercomputer and a pc cluster.
The optimal design was performed with two chosen examples: a composite plate and a
composite stiffened panel. The design variables were the number of plies and the ply
angle in each ply. In case of the stiffened panels, the size and the location of the
stiffeners were also considered as the design variables. The objective function was
defined as the product of the nondimensional weight and the strength. The optimization
results showed better performances than conventional designs.