Operational Modal Analysis and Structure Health Monitoring

Modal parameters are able to characterize any structure uniquely. All the structural elements and the respective boundary conditions have a direct impact in all of the modal parameters (natural frequencies, damping ratios and mode shapes), making them suitable to detect damage along the structure. To this end, experimental identification of the modal parameters is necessary and must be conducted periodically. In the last decade, operational modal analysis has been developed to this purpose. It allows the identification of the modal parameter with the structures in operational conditions and using ambient excitation. Several improvements in the field were recently made with the computation of modal parameters uncertainties and with the automation in the identification process. Therefore, vibration-base structural health monitoring system is getting popular for critical civil structures such as bridges, high buildings and old constructions.

Keywords:Operational modal analysis; Structure health monitoring; Uncertainty quantification; Stochastic modeling; Linear time-invariant systems; Identification