A laser ultrasonic excitation and detection system and method for realizing ultrasonic fast scanning and fixed-point focusing

Abstract

The invention discloses a laser ultrasonic excitation and detection system and method for realizing ultrasonic fast scanning and fixed-point focusing. The system includes a laser generator, a laser transmission device, a precision moving device, a laser ultrasonic signal detection device and a control module, and a laser generator The emitted laser light is irradiated on the surface of the tested sample through the laser transmission device, and the laser ultrasonic signal detection device detects the ultrasonic signal inside the tested sample, and transmits it to the control module for analysis, processing and display, and determines the initial feature position of the test, and the control module feedbacks the control Precisely move the device to adjust the distance between the optical fibers at the output end of the laser transmission device to obtain clear features of the inspected features. The present invention realizes the steering and fixed-point focusing of the laser ultrasonic signal enhancement direction by controlling the distance between the optical fibers of the optical fiber array, so as to realize the rapid scanning of the tested sample and obtain the further shape characteristics of the tested features, and significantly improve the detection efficiency and flaw detection accuracy.

Description

technical field [0001] The invention belongs to the field of non-destructive testing, and relates to a laser ultrasonic excitation and detection system and method for realizing ultrasonic fast scanning and fixed-point focusing. Background technique [0002] Laser ultrasound is a non-contact, high-precision, non-destructive new ultrasonic testing technology. It uses laser pulses to excite ultrasonic waves in the workpiece to be detected, and uses laser beams to detect the propagation of ultrasonic waves to obtain workpiece information, such as workpiece thickness, internal and surface characteristics, material parameters, etc. It has broad application prospects in material inspection feature detection, processing inspection, and equipment monitoring in harsh environments such as high temperature, corrosion, and radiation. [0003] Compared with other non-destructive testing technologies, laser ultrasonic testing technology has the advantages of low cost, easy operation, and ...

AI Technical Summary

Problems solved by technology

However, the existing laser ultrasonic excitation and detection methods generally use a single point source or a line source to irradiate the sample to be tested, which is limited by the energy and repetition rate of the pulsed laser, the excitation effect and signal intensity, and the detection rate are limited, which is not conducive to the detection of samples. For the detection of internal features to be inspected, it is necessary to enhance the intensity of ultrasonic waves through the method of phased array laser excitation to realize the detection of internal features to be inspected

However, most of the existing array laser methods cannot realize the rapid steering and fixed-point focusing of the ultrasonic signal enhancement direction, and its efficiency is low and the accuracy is not high.

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