AN ALGORITHM FOR SOLVING THE SYSTEM-LEVEL PROBLEM IN MULTILEVEL OPTIMIZATION

A multilevel optimization approach applicable to nonhierarchic coupled systems is presented. The approach includes a general treatment of de sign (or behaviour) constraints and coupling constraints at the discip line level through the use of norms. Three different types of norms ar e examined - the max norm, the Kriesselmeier-Steinhauser (KS) norm, an d the l(p) norm. The max norm is recommended. The approach is demonstr ated on a class of hub frame structures that simulate multidisciplinar y systems. The max norm is shown to produce system-level constraint fu nctions which are nonsmooth. A cutting-plane algorithm is presented, w hich adequately deals with the resulting corners in the constraint fun ctions. The algorithm is tested on hub frames with an increasing numbe r of members (which simulate disciplines), and the results are summari zed.