U. Topal, Karadeniz Technical University, Trabzon, Turkey

Summary: Laminated composite structures are made up of two or more layers bonded together to achieve the best properties of the constituent layers. An advantage of laminated composite materials over conventional ones is the possibility of tailoring their properties to the specific requirements of a given application. The tailoring can be achieved by optimising the material properties with regard to design objectives. Optimum design of fiber composite plates presents one of the most interesting and yet intricate problems of structural mechanics. This is chiefly due to the increase in the number of the variables and levels of interrelation as compared to the case of isotropic materials. Recently, one of the most important reasons for using composite materials in mechanical/aerospace engineering applications is for reducing structural weight due to the high specific stiffness/strength of the composites. The current work deals with optimal design of simply supported laminated composite plate structures subject to uniform pressure loading. The composite laminate design process typically involves optimization of the laminate thickness. The structural weight is considered as the objective function (minimizing weight). Constraints are imposed on deflection design. The laminated composite plate is constructed of four layers of equal thickness. The finite element method, based on Mindlin plate and shell theory, is used the application in conjuction with the Modified Feasible Direction mathematical programming approach in order to obtain the optimal design. Numerical examples are performed for investigating the effect of different plate aspect ratios, boundary conditions, ply angles and number of plies on the results.