STRUCTURAL OPTIMIZATION WITH STRESS AND AEROELASTIC CONSTRAINTS USING EXPANDABLE MODAL BASIS

Recent developments of the modal-based aeroelastic optimization approach facilitated efficient treatment of static-aeroelastic and stress constraints. The reduced-size models use low-frequency normal modes of the baseline structure as fixed generalized coordinated throughout the optimization process. The modal approach is extended in this paper to allow the expansion of the modal basis by adding static modes generated in previous design steps. Being based on modal perturbations stored in the modal data base before the optimization process starts, the basis expansion is efficient and it convergences faster to the optimal design. Numerical examples with realistic fighter-aircraft models demonstrate practical applications with CPU speed-up factors of about 10, compared to the regular discrete-coordinate approach, with negligible loss of accuracy.