Structural identification using a combination of subspace analysis and block sum transformation

In this article a combination of the subspace method with the block sum tra nsformation is presented. Applying the block sum transformation a measuring window of the length T can be subdivided into intervals T* where T* is an integer part of T. The data of all subwindows are added up to only one, whi ch can then be analysed with the subspace method. Without a loss of accurac y the number of sample points can be reduced substantially and the computin g effort is minimised. Sine sweep excitation is extremely useful for the an alysis of structures with neighbouring eigenfrequencies or with high dampin g. The application of the proposed structural identification routine is num erically and experimentally validated. (C) 2001 Academic Press.