Abstract
This paper discusses the modal decomposition of the Operating Deflection Shapes (ODSs).The ODSs offer an important contribution in the understanding of the dynamic behavior of a system under operation.The modal decomposition can express each ODS as a linear combination of modes, and have been usually done in a least squares sense.However, there are scarcely modal vectors which cross at right angles, and consequently the result obtained from the ordinary method give obscure interpretation.Therefore we propose that the modal decomposition based on the General Definition of Projectors (GDOP) is most suitable for the detailed description of the modal decomposition.Moreover, we present a new model correlation technique based on the GDOP to verify the modal vectors, because the accuracy of the modal vectors is important in the modal decomposition.These approaches are demostrated using numerically simulated FRFs and modal vectors.As a result, it was shown that these approaches give good clearer results compared to the ordinary modal decomposition method.
