Abstract: | Using the cross-sectional area function as the design variable, we determine the optimal design of a transversally vibrating, thin, elastic beam or rotating shaft that maximizes the difference.n -.n-1 between two adjacent natural frequencies or critical whirling speeds wn and.n-1 of given order. The beams have geometrically similar cross- sections while the shafts are restricted to be circular, and a minimum constraint is prescribed for the cross-sectional area. The volume, length and boundary conditions are assumed to be given, and the beams or shafts may be equipped with given, non-structural masses or disks. |