SYSTEM FOR DETECTING DEFECT IN PLATE BY USING LASER-GENERATED FOCUSED LAMB WAVE CAPABLE OF GENERATING ULTRASONIC WAVES

摘要

PURPOSE: A system for detecting a defect in a plate by using a laser-generated focused lamb wave is provided to generate ultrasonic waves having superior intensity under low laser energy density. CONSTITUTION: A system for detecting a defect in a plate by using a laser-generated focused lamb wave includes a pulse laser generating device(10) for generating a laser beam. An expander(20) expands width of the laser beam generated from the pulse laser generating device(10) in order to prevent a surface of a sample from being damaged by irradiating the laser beam with an excessive energy into a unit area of the sample. A sectional shape of the width of the laser beam expanded by the beam expander(20) is changed to a circular shape by a circular-shape slit(30).