Defect two-dimensional morphology imaging detection method based on multi-mode acoustic beam synthetic aperture focusing

Abstract

The invention discloses a defect two-dimensional morphology imaging detection method based on multi-mode acoustic beam synthetic aperture focusing, belonging to the technical field of nondestructive testing. According to the method, a phased array ultrasonic detector, a phased array ultrasonic probe and a phased array ultrasonic detection system of an oblique wedge block are adopted; and signal acquisition of a detected test block is performed by the electronic scanning function of the phased array ultrasonic detector to obtain A-scanning signal of each aperture of the phased array ultrasonic probe. According to different mode conversion types of excitation acoustic beam of each aperture on the interface between the wedge block and test block, at the bottom of the test block and on the defect surface, proper multi-mode acoustic beam is selected from 8 acoustic beam transmission modes. Based on SAFT imaging principle and Fermat's theorem, the transmission delay of the multi-mode acoustic beam of each aperture is calculated, and amplitudes are overlapped to obtain a reconstructed SAFT image, thus realizing complete representation of defect two-dimensional morphology features. The invention can realize correct recognition of volume type and area type defects so as to realize accurate quantification of defect length, depth and orientation, and has relatively high engineering application value.

Description

Technical field [0001] The invention relates to a defect two-dimensional shape imaging detection method based on multi-mode acoustic beam synthetic aperture focusing, which belongs to the technical field of nondestructive detection. Background technique [0002] The qualitative, quantitative, positioning and orientation of defects are the research work that NDT always pays attention to. Ultrasonic detection technology is widely used in defect detection because of its high detection sensitivity and intuitive display of detection results. However, conventional ultrasound uses the echo amplitude and phase characteristics in the A-scan signal for defect detection, and it is difficult to determine the nature of the defect; conventional phased array ultrasound technology can achieve defect imaging detection, but only the part of the defect morphology is presented The characteristics may cause misjudgment of the nature of the defect, deviation of the quantitative and positioning result...

AI Technical Summary

Problems solved by technology

[0004] The present invention provides a defect two-dimensional shape imaging detection method based on multi-mode acoustic beam synthetic aperture focusing. The array electronic scanning function and the inclined wedge are used to collect A-scan signals containing multi-mode conversion information such as defect surface reflection waves. According to Fermat's theorem and SAFT imaging principle, the A-scan signals are time-delayed and amplitude-superimposed, and then can be obtained. SAFT image that fully characterizes the two-dimensional morphology of defects

Images