Probe and ultrasonic scanning method for detecting inner cavity of whole structure of composite material

Abstract

The invention belongs to nondestructive detection technologies of structures of composite material, and the like, and relates to a probe and an ultrasonic scanning method for detecting an inner cavity of a whole structure of the composite material. The probe comprises an acoustic unit and a scanner, wherein the acoustic unit is positioned in coaxial cylindrical through-holes in middle positions of an upper clamping block and a lower clamping block in the scanner and keeps being in clearance fit with the coaxial cylindrical through-holes. The ultrasonic scanning method comprises the steps that the acoustical unit is placed on the upper clamping block in the scanner and connected with an external ultrasonic detection instrument; a water supply hose is connected with an external water supply loop; water enters from a straight hole of the lower clamping block, is conveyed to a circular groove and then flows along a fine slit between a coupling cavity jacket and the wall of the inner hole of the lower clamping block to the surface of a detected closed vertical wall, so as to form an acoustic wave coupling water film on the surface of the vertical wall; and ultrasonic waves are vertically transmitted to and received by the vertical wall of the closed inner cavity of the detected whole structure through the acoustic unit. By using the ultrasonic scanning method, the ultrasonic scanning stability of the vertical wall of the closed inner cavity is greatly improved and the reliability of a detection result is remarkably increased.

Description

technical field [0001] The invention belongs to the non-destructive testing technology of structures such as composite materials, and relates to a probe and an ultrasonic scanning method for detecting the inner cavity of a composite material integral structure. Background technique [0002] The overall structure of composite materials is an important engineering structure designed and adopted in the fields of aviation, aerospace, civil aviation, electronics, weapons, ships, electric power, etc., and is usually designed with internal cavity or internal hole structure characteristics. Since such structures are usually load-bearing structures, 100% non-destructive testing is required in engineering. However, due to the closedness and inaccessibility of the inner cavity of this kind of integral structure, it is usually difficult to realize non-destructive testing for it. [0003] At present, the ultrasonic method is mainly used to realize the non-destructive inspection of the i...

AI Technical Summary

Problems solved by technology

[0004] At present, the ultrasonic probes that can be used in the inner cavity of the overall structure such as composite materials have the following outstanding shortcomings: (a) the blind area of ​​the surface detection is large, usually above 0.8-1mm; (b) the quality of the acoustic signal from the ultrasonic probe is not high, and the signal is regular Not clear, affecting defect discrimination and qualitative analysis; (3) low resolution

[0005] (1) For composite materials and other integral structures with closed inner cavities, the manual ultrasonic scanning detection method is mainly used at present. The ultrasonic probe is rigidly connected through the mechanical connecting rod, and the mechanical connecting rod is manually operated to realize the detection of the ultrasonic probe on the part to be tested. For scanning, the probe is coupled with the surface of the detected part by rigid contact, and its outstanding shortcomings are: (a) Due to the complexity of the overall cavity structure and surface curvature changes such as composite materials, it is difficult to achieve alignment of the probe through an external rigid connecting rod. control and ensure a stable acoustic coupling between it and the surface of the detected part, resulting in severe instability of the transducer’s transmitted / received signal, which directly affects the reliability of the detection results; (b) during the scanning process, through the external Rigid connecting rods, it is difficult to ensure that the attitude and position of the probe can be tracked stably with the surface of the closed inner cavity to be tested, thus affecting the reliability of ultrasonic testing results

[0006] (2) For the short-stroke inner cavity with large internal space and rules, there are currently special detection devices designed to perform ultrasonic automatic detection on the regular parts of the overall structure inner cavity. Acoustic coupling, the technical cost is expensive, for most of the overall structure, due to accessibility, site, environmental conditions and other reasons, it is impossible to automatically scan and detect the closed cavity of the engineering structure

Images