Abstract: A multi-mode approach for real-time inspection of structural components may be applied to rapid, wide area measurement of thickness of thick plate-like structures using full-field multi-mode response measurement and analysis. The approach may allow estimation of thickness from full-field multi-mode response to single-tone ultrasonic excitation in thick plates. The approach may utilize wavenumber information across all available wave modes in order to make wavenumber spectroscopy sensitive to changes in thickness for a broader range of nominal initial thicknesses.

Abstract: A method for extracting vibrational modes of a structure includes: receiving a plurality of video frames, each of the video frames including a plurality of pixels; decomposing each of the video frames on a plurality of spatial scales in accordance with complex steerable pyramid filters to obtain a filter response for each of the spatial scales; computing a plurality of local phases of the pixels of each frame; removing a temporal mean from each frame to obtain a plurality of factored vibration motion functions; performing principal component analysis on the factored vibration motion functions to obtain principal components; blind source separating the principal components to compute a plurality of modal coordinates; computing frequency and damping ratios in accordance with the modal coordinates; and outputting the computed frequency and damping ratios.

Abstract: A multi-mode approach for real-time inspection of structural components may be applied to rapid, wide area measurement of thickness of thick plate-like structures using full-field multi-mode response measurement and analysis. The approach may allow estimation of thickness from full-field multi-mode response to single-tone ultrasonic excitation in thick plates. The approach may utilize wavenumber information across all available wave modes in order to make wavenumber spectroscopy sensitive to changes in thickness for a broader range of nominal initial thicknesses.

Abstract: A method for extracting vibrational modes of a structure includes: receiving a plurality of video frames, each of the video frames including a plurality of pixels; decomposing each of the video frames on a plurality of spatial scales in accordance with complex steerable pyramid filters to obtain a filter response for each of the spatial scales; computing a plurality of local phases of the pixels of each frame; removing a temporal mean from each frame to obtain a plurality of factored vibration motion functions; performing principal component analysis on the factored vibration motion functions to obtain principal components; blind source separating the principal components to compute a plurality of modal coordinates; computing frequency and damping ratios in accordance with the modal coordinates; and outputting the computed frequency and damping ratios.