Experimental investigation of defect imaging using a phased array probe with a stacked plate buffer

The authors have previously validated defect imaging using stacked plate buffer and a phased array probe by numerical simulations. This study experimentally verifies the feasibility of this approach. A stacked plate buffer created by considering the dispersion of the S0 mode of Lamb waves was used for the first experiments, which showed that high intensity spurious areas appeared and defect images were blurred. Numerical analysis of the propagation of S0 modes in the plate revealed that trailing waves cause the high intensity spurious areas. Theoretical and numerical analyses indicated that the trailing waves can be removed by increasing the width of the plate. Finally, experiments using wider plates verified that a phased array probe with a stacked plate buffer can eliminate the high intensity spurious areas and clarify the defect images.