Optimum Design of Laminated Composite Structures

Because of their superior mechanical properties compared to single phase materials, laminated fibrous composite materials are finding a wide range of applications in structural design, especially for lightweight structures that have stringent stiffness and strength requirements. Designing with laminated composites, on the other hand, has become a challenge for the designer because of a wide range of parameters that can be varied, and because the complex behavior and multiple failure modes of these structures require sophisticated analysis techniques. Finding an efficient composite structural design that meets the requirements of a certain application can be achieved not only by sizing the cross-sectional areas and member thicknesses, but also by global or local tailoring of the material properties through selective use of orientation, number, and stacking sequence of laminae that make up the composite laminate. The increased number of design variables is both a blessing and a curse for the designer, in that he has more control to fine-tune his structure to meet design requirements, but only if he can figure out how to select those design variables. The possibility of achieving an efficient design that is safe against multiple failure mechanisms, coupled with the difficulty in selecting the values of a large set of design variables makes structural optimization an obvious tool for the design of laminated composite structures.