A MULTIDISCIPLINARY OPTIMIZATION USING SEMIANALYTICAL SENSITIVITY ANALYSIS PROCEDURE AND MULTILEVEL DECOMPOSITION

This paper addresses the development of a multidisciplinary optimizati on procedure using an efficient semi-analytical sensitivity analysis t echnique and multilevel decomposition for the design of aerospace vehi cles. A semi-analytical sensitivity analysis procedure is developed fo r aerodynamic design sensitivities. Accuracy and efficiency of the sen sitivity analysis procedure is established through comparison of the r esults with those obtained using a finite difference technique. The op timization problem, with the integration of aerodynamics and structure s, is decomposed into two levels. Optimization is performed for improv ed aerodynamic performance at the first level and improved structural performance at the second level. Aerodynamic analysis is performed by solving the three-dimensional parabolized Navier Stokes equations. A n onlinear programming technique and an approximate analysis procedure a re used for optimization. The procedure developed is applied to design the wing of a high speed aircraft. Results obtained show significant improvements in the wing aerodynamic and structural performance when c ompared to a reference or baseline wing configuration. The use of the semi-analytical sensitivity technique provides significant computation al savings.