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Abstract:

This work deals with the problem of estimating damage accumulation due to fatigue in the entire body of a metallic structure using operational vibration measurements collected from a limited number of sensors installed on a structure. A recently proposed joint input-state estimation filter is extended to estimate the strain response time histories in the entire body of the structure using the output-only vibration measurements. The estimates hold for any excitation with arbitrary temporal variation and spatial distribution over the structure. Such predictions are then integrated with damage accumulation models, S-N fatigue curves and rainflow stress cycle counting methods to estimate fatigue damage accumulation maps covering the entire body of the structure. The method is validated using simulated vibration measurements for a laboratory steel beam, generated from impulse and stochastic excitations.