FINITE-ELEMENT MODEL UPDATING USING FREQUENCY-RESPONSE FUNCTION DATA .1. THEORY AND INITIAL INVESTIGATION

This work outlines the basic formulation for the frequency response function based updating method and discusses several possible solution strategies. Using simulated experimental data, systematic studies are conducted in the case of a simple beam structure to investigate the uniqueness of the updated model, the effectiveness of the technique in the case of noisy and incomplete experimental data, the importance of excitation direction and the implications of co-ordinate mismatch. Numerical aspects such as stability and convergence are also studied in some detail. Finally, the basic algorithm is extended to deal with complex FRF data and the updating of a proportional damping matrix is attempted using experimentally-measured FRF data. A number of difficulties are identified and possible remedies are suggested.