An investigation of Lamb wave with quantitative laser ultrasound visualization system

This study employs an experimental measurement called quantitative laser ultrasound visualization system (QLUVS) for investigating the propagating behavior and dispersion behavior of Lamb wave. The QLUVS uses a pulsed laser generate acoustic waves which are then detected with a piezoelectric longitudinal transducer. By utilizing the generating laser to scanning together with the aid of reciprocal theorem, dynamic behaviors of Lamb wave modes propagating behavior can be reconstructed. Through image reconstruction, the Lamb wave propagating phenomenon encountering the different material, like as isotropic, anisotropic or coated/non-coated material can be showed obviously. Further, the dispersion spectra can be extracted in whole region by utilizing QLUVS and 2-D FFT analysis method.