In this thesis the use of optimization process engineering problems involving eigen value solution has been addressed. Maximization of fundamental frequency and maximaization of critical buckling loads of rectangular plates are, namely, the problems considered in this study. The Finite Element Method, using thin plate elements, as well as a Rayleigh- Ritz Method, using shape- functions defined over the whole domain, have been employed to formulate the eigen value problems. The plate thickness at each point ( representing a small area ) has been considered as the disighn variable. For practical use the optimum variation of plate thickness obtained in the optimization process has been presented for variuse boundary conditions and different aspect ratios of plates.
