OPTIMUM DESIGN OF STRUCTURES WITH BOTH NATURAL FREQUENCY AND FREQUENCY-RESPONSE CONSTRAINTS

An efficient method is developed to compute the sensitivities of eigenvalues, eigenvectors and frequency responses in a reduced approximate model. The reanalyses of a modified structure for those dynamic responses are also derived in the approximate model. An optimization process utilizing the efficiently calculated sensitivities and reanalyses of the modified structure is formed. The difficulties of finding eigenvector sensitivities for repeated modes have also been addressed and averted in the approximate model. Two numerical examples show satisfactory outcomes by using this proposed approach.