The introduction of composite materials in aircraft structures is having a profound effect on the design process. These materials permit the designer to tailor material properties to improve structural and aerodynamic performance. In order to obtain maximum benefits, a more integrated multidisciplinary design process is required. Furthermore, because of the complexity of the combined aerodynamic/structural design process numerical optimization methods are required.

The present research is focused on a major difficulty associated with the multidisciplinary design optimization process - its enormous computational cost. We consider two approaches for reducing this computational burden: (i) development of efficient methods for cross-sensitivity calculation using perturbation methods; and (ii) the use of approximate numerical optimization procedures. Our efforts are concentrated upon combined aerodynamic-structural optimization. Results are presented for the integrated design of a sailplane wing. The impact of our computational procedures on the computational costs of integrated designs are discussed.