A set of scaled mode shapes is a complete representation ofrnthe linear dynamic properties of a structure. They can bernused for a variety of different analyses, including structuralrnmodifications, forced response simulations, excitation forcerncalculations from measured responses, and FRF synthesisrnfor comparison with experimental data.rnWhen mode shapes are obtained exp erimentally from operatingrndata, they are not properly scaled to preserve the massrn& elastic properties of the structure. By operating data, wernmean that only structural responses were measured. Excitationrnforces were not measured.rnIn this paper, we review the traditional methods for scalingrnexperimental mode shapes using FRFs, and also introducerntwo new methods that don't require FRF measurement. Thernnew methods combine a search algorithm with the SDMrn(Structural Dynamics Modification or eigenvalue modification)rnalgorithm to perform a series of structural modificationsrnuntil proper scaling of the mode shapes is achieved.rnDetails of the methods and examples of their use are included.
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