ASA 125th Meeting Ottawa 1993 May

4pSA3. Estimation of dynamic forces via modal decomposition of operational deflection shape measurements.

David C. Warwick

Hull Structures and Acoust. Branch, Carderock Div., Naval Surface Warfare Ctr., Bethesda, MD 20084

John J. Gilheany

Catholic Univ. of America, Washington, DC 20064

The results of modal analysis are used to derive a set of modal filters that are applied to operational deflection shape measurements to estimate modal contributions and physical forces for structures subject to multiple, correlated and uncorrelated, external excitations. Singular value decomposition is applied to measured cross spectral density functions to decompose response measurements into contributions associated with each independent external excitation. Generalized and physical forces, coherent to each independent source, are determined from estimated modal parameters. The approach is demonstrated for single and multiple, correlated and uncorrelated, external excitations.