Sparse multi-time wavenumber analysis method based on incomplete guided wavefield data

Two-dimensional ultrasonic guided wavefield data carry rich waveguide structure information and are widely used for imaging and quantitative detection of structural damage. Focusing on the problem of high-volume data needs to be collected in the traditional damage imaging and quantitative detection method based on ultrasonic guided wavefield, this paper proposes a sparse multi-time wavenumber analysis method based on incomplete guided wavefield data. Firstly, the sparse sampling method of wavefield and the appropriate analysis dictionary are selected to construct the sensing matrix, and the compressed sensing equation is solved to reconstruct the snapshot of wavefield at multiple moments. Then, the continuous phase of the wavefield at multiple times is calculated, and the spatial phase gradient is calculated to obtain the wavenumber. After extracting the multi-time median wavenumber for each measurement point, the quantitative detection of damage is realized using the dispersion relationship between wavenumber and thickness. The method is first verified in the simulation, and then experimentally verified in an aluminum plate containing rectangular groove defects and a carbon fiber reinforced polymer plate with delamination defects. The simulation and experimental findings indicate that the proposed approach markedly decreases the quantity of measurement points while maintaining imaging quality and damage quantification accuracy.