High-Speed Camera Based Methods for Experimental and Operational Modal Analysis

In recent years, experimental and operational modal analysis (EMA/OMA) based on high-speed cameras research has attracted significant attention. Full-field structural identification opens new possibilities for structural health monitoring, model updating, and identification of structural parameters. Several new methods have been proposed that enable the identification of sub-pixel displacements. Recently, infrared (IR) cameras have also been used to identify strain deflection shapes. This research will present the state-of-the-art approaches for single high-speed camera-based structural identification, including the identification of 3D deflection shapes. Initially, the hybrid electromechanical accelerometer (EMA) based on simplified optical flow with a single classical accelerometer will be presented. This method identifies amplitudes of vibration at the level of 1/100,000th of a pixel. Further, frequency domain triangulation will be presented to extend the hybrid method to identification of spatial deflection shapes; the frequency domain triangulation enables to combine an arbitrary number of views significantly overdeterming the identification and therefore offering the posibility to reduce the noise. Additionally, the single pixel-based EMA where EMA is performed at the level of a single pixel and thermoelasticity-based strain operational deflection shape identification will be presented.