When detecting near-surface defects of the workpiece,it is difficult to accurately read the propagation time difference between the direct wave and the diffracted longitudinal wave at the end of the defect due to their aliasing effect during ultrasonic TOFD inspection,thus restricts defect positioning.The mode-converted wave method proposed in this paper is based on the TOFD B-scan image,and uses the diffracted shear wave with longer propagation time for separation from the direct wave and achieve near-surface defect quantification.This study carries out inspection on aluminium alloy plate with the thickness of 20mm and 10mm,and the inspection results are in good consistent with the simulation results,with the quantitative error of the defect depth less than 3.3%,which verifies effectiveness of the proposed method.
关键词
超声检测/衍射时差法/盲区/模式转换波/定量检测
Key words
Ultrasonic inspection/diffraction time difference method/blind zone/mode-converted wave/quantitative detection
维普
万方数据