Substructure damage identification based on response reconstruction in frequency domain and model updating

A substructural damage identification approach based on dynamic response reconstruction in frequency domain is proposed with numerical and experimental verifications. The response reconstruction is based on transforming the measured responses into responses at other locations with the transmissibility matrix. Damage identification is conducted by minimizing the difference between a measured response vector and the reconstructed response vector. Measured acceleration responses from the damaged substructure and the finite element model of the intact substructure only are required in the identification algorithm. A dynamic response sensitivity-based method is used for the damage identification. Numerical studies on a seven-storey plane frame structure are conducted to validate the correctness and effectiveness of the proposed approach. The simulated damage can be identified efficiently with 10% noise effect in the measurements and random initial model errors in the finite element model of the structure. Experimental studies on a steel plane frame structure in the laboratory are performed to further verify the response reconstruction in frequency domain and the proposed substructural damage identification approach. The locations of the introduced damage are detected accurately and the stiffness reductions in the damaged elements of the target substructure are identified close to the theoretical values.