A Mass or Stiffness Addition Technique for Structural Parameter Updating
NG Nalitolela, JET Penny & MI Friswell (Aston University)
Modal Analysis: The International Journal of Analytical and Experimental Modal Analysis, Vol. 7, No. 3, 1992, pp. 157-168
Most methods used to update dynamic structural models use either frequency response data or both eigenvalues and mode shape data. This paper presents a technique to adjust the parameters using eigenvalues alone. Eigenvalues may be measured very accuractely whereas mode shapes often contain substantial errors. The structure and its theoretical model are perturbed by adding mass or stiffness. The measured eigenvalues before and after mass addition are used to update the parameters by sensitivity analysis. It is shown that with error-free data and a proper choice of the perturbing coordinates, exact parameters can be identified from eigenvalues alone using unconstrained optimization. Due to measurement errors and possible inaccuracies in the structure of the model matrices, the parameters of a real structure are adjusted by incorporating a constraint of minimum changes from the initial estimates using a Bayesian estimator.
This material has been published in the Modal Analysis: The International Journal of Analytical and Experimental Modal Analysis, Vol. 7, No. 3, 1992, pp. 157-168, the only definitive repository of the content that has been certified and accepted after peer review. Copyright and all rights therein are retained by Society for Experimental Mechanics. The Society for Experimental Mechanics stopped publishing Modal Analysis at the end of 1996. Sage Science Publishers, Thousand Oaks, California, purchased the rights and incorporated Modal Analysis into its existing publication, The Journal of Vibration and Control.
Society for Experimental Mechanics