METHOD AND DEVICE FOR MEASURING ACOUSTIC VELOCITY OF LONGITUDINAL WAVE AND TRANSVERSE WAVE IN MATERIAL BY LASER ULTRASONIC METHOD

摘要

PPROBLEM TO BE SOLVED: To reduce damage of an inspecting object by laser beam irradiation in a laser ultrasonic detector, and to measure the acoustic velocity of a longitudinal wave and transverse wave. PSOLUTION: The laser ultrasonic detector 10c includes: a laser light source 11 for generating ultrasonic wave for linearly irradiating the inspecting object with a pulse laser beam for generating ultrasonic wave to generate the ultrasonic wave; a laser light source 12 for detecting ultrasonic wave for irradiating the inspecting object with a laser beam for detecting ultrasonic wave to detect the ultrasonic wave; a diffraction grating 14 for irradiating the surface of the inspecting object with diffracted light by diffracting the pulse laser beam for generating ultrasonic wave; a calculation section 61 for asymmetrical wave frequency to calculate the frequency of asymmetrical-wave plate wave by frequency-analyzing the ultrasonic wave generated by irradiation of the diffracted light; a calculation section 62 for a longitudinal wave acoustic velocity to calculate the longitudinal wave acoustic by frequency-analyzing the ultrasonic wave generated by linear irradiation of the pulse laser beam for generating ultrasonic wave; and a calculation section 63 for transverse wave acoustic velocity to calculate the frequency of the asymmetrical-wave plate wave and the transverse wave acoustic velocity corresponding to the longitudinal wave acoustic velocity. PCOPYRIGHT: (C)2010,JPO&INPIT