EXPLORATION OF SUBSTITUTION OF REPEATED MODE SUBSPACES FOR CLOSELY SPACED MODE SUBSPACES

A new quantitative concept is introduced in this paper, which may be u sed to facilitate the measurement of the controllability of a subspace similar to subspace controllability degree. Then the concrete form of the subspace controllability degree of a flexible structure is derive d, and the errors of subspace controllability degree and dynamical res ponse caused by the substitution of a repeated mode subspace for a clo sely spaced mode subspace are discussed. All the results show that thi s substitution is rational under some conditions.