Ultrasonic laser excitation and detection system and method for achieving ultrasonic rapid scanning and fixed-point focusing

Abstract

The invention discloses an ultrasonic laser excitation and detection system and method for achieving ultrasonic rapid scanning and fixed-point focusing. The system includes a laser generator, a lasertransmitting device, a precise moving device, an ultrasonic laser signal detection device and a control module. A laser generated by the laser generator is emitted to the surface of a detected sampleafter passing through the laser transmission device, the ultrasonic laser signal detection device detects an ultrasonic signal in the detected sample and transmits the ultrasonic signal to a control module for analysis processing and display, an initial detected characteristic position is determined, and the control module conducts feedback control on the precise moving device to adjust the spacing between every two adjacent optical fibers at the output end of the laser transmission device so as to obtain clear appearance characteristic details of a detected characteristic. According to the system and the method, steering and fixed-point focusing of the ultrasonic laser signal in the enhancement direction are achieved by controlling the spacing between every two optical fibers of an optical fiber array, so that rapid scanning of the detected sample is achieved, the more appearance characteristic details of the detected characteristic are obtained, and the detection efficiency and the flaw detection precision are obviously improved.

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.

Images