2019 年 30 巻 1_2 号 p. 6-10
Laser light probing method is introduced in the ultrasonic measurement system to detect and identify the position of residual stress. Acryl sample having 1.5mm slit and compression or tension stress is used to demonstrate the usefulness of the method. The laser light via the APD sensor and vector signal analyzer（VSA）analyzed fundamental and second harmonic component including in the ultrasonic wave detected by the APD. Second harmonic component increases around the residual stress and rapid variation area of stress is revealed. Possibility of novel evaluation of the residual stress by the laser light probing method is also demonstrated.