Eddy radar defect detecting, quantifying and imaging method and system

Abstract

The invention discloses an eddy radar defect detecting, quantifying and imaging method and system. According to the method, excitation signals in different modes such as pulse, sine, frequency modulation and phase modulation are adopted to excite a signal driving eddy sensor, and eddy can be sensed in a detected object. An output signal of the eddy sensor is taken as a time domain response signal, and the time domain response signal of an area free from defects is taken as a reference signal. A cross-correlation algorithm is applied to the time domain response signal and the reference signal, so that a cross-correlation amplitude value and phase can be obtained. Characteristic values for defect detection can be extracted from the cross-correlation amplitude value and the phase; through standard test piece experiment, a quantitative corresponding relationship of the characteristic value and the depth can be established, and quantification of the defect depth can be achieved; the cross-correlation amplitude value and the phase of each detection point on a scanning route can be displayed, and B-scanning imaging can be achieved; a scanning mechanism is adopted to detect one area, and the characteristic values are adopted for C-scanning imaging. The method and the system have the advantages of high signal to noise ratio, accurate depth quantification, good interference resistance, and the like, and can be applied to the field of nondestructive detection.

Description

technical field [0001] The invention belongs to the technical fields of equipment nondestructive testing, material characterization evaluation, structural health monitoring, product quality control and the like, in particular to an eddy current electromagnetic nondestructive testing method and system. Background technique [0002] With the development of modern science and industrial technology, non-destructive testing technology has become a necessary means to ensure product quality and equipment operation safety. At present, the representative non-destructive testing technologies mainly include radiographic testing, ultrasonic testing, penetrant testing, magnetic particle testing, Eddy Current Testing (ECT), as well as the rapidly developing thermal imaging testing, dislocation speckle interference and other technologies. [0003] Eddy current testing technology is a non-destructive testing method based on the principle of electromagnetic induction, which is suitable for c...

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Problems solved by technology

[0007] The current eddy current testing technology also has some deficiencies, mainly in: 1) The signal-to-noise ratio of the signal is low due to the influence of electromagnetic field attenuation and noise interference; 2) The quantitative accuracy of the depth of internal defects is not high, and it is difficult to judge the distance between defects 3) The C-scan imaging mainly relies on the time-domain eigenvalue and the position of the detection point, and the anti-interference is poor

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