The Signal Reception And Processing Of Laser Ultrasonic Detection

NDT techniques have detected assess the role which can not be ignored for fullcontinuity of the materials in industrial applications and reliable practicality. Laserultrasonic detection uses penetration ability of ultrasonic in excellent material to detectinternal defects in materials,which is one of the new techniques of NDT. It is based onthe traditional ultrasonic strong penetrating power, at the same time, application of thenon-contact optical detection,becoming the popular technology of the NDT.This paper outlined the system of laser ultrasonic detection technology in theorypart and the way to work: details of the two main parts of the mechanism of laserexcitation ultrasound in the system, analysis the working principle of each part of thesystem. Including thermoelastic effects and ablation effect,focused on the thermoelasticeffect mechanism,the approach of pulsed laser source into a line source model; then listsseveral detection methods to detect ultrasonic receiver section, including sensors andoptical receiver assay method, and summarizes the characteristics of these methods tomake comparisons.With the laser holographic detection work in laboratory,we proposes a new methoddetecting ultrasonic signal using holographic double exposure technique, prove thefeasibility of the method in theory, derives the relationship between ultrasonic vibrationsignal and the interference fringe intensity. According to the relation access the limitsensitivity of laser ultrasonic testing signal amplitude characterization,which has acertain reference value to the application of laser ultrasonic detection.According to the theory of laser holography,this paper discuss the detection of keytechnology experiment and the signal processing method of the method is discussedResearch shows that the way of laser ultrasonic detection material of flaw isfeasible and effective. Signal detection algorithms in this paper can be carried out in thelaser ultrasonic testing receiver technology,which has important application value.