Abstract: A stress evaluation method for evaluating stress acting on a test piece includes the steps of transmitting acoustic waves including a surface wave, a longitudinal wave, and a shear wave through the test piece; receiving the acoustic waves after they have propagated through the test piece; obtaining acoustic velocities of the surface wave at a non-loaded portion and a loaded portion of the test piece based on the received acoustic waves; evaluating a stress in a surface layer of the test piece based on a difference between the surface wave acoustic velocities at the non-loaded portion and the loaded portion and a predetermined relationship between surface wave acoustic velocities and stresses; obtaining an acoustic velocity of the longitudinal wave at the non-loaded portion based on the received acoustic waves; calculating an acoustic velocity of the shear wave at the loaded portion based on the received acoustic waves and the longitudinal wave acoustic velocity at the non-loaded portion; evaluating an interna

Abstract: A stress evaluation method for evaluating stress acting on a test piece includes the steps of transmitting acoustic waves including a surface wave, a longitudinal wave, and a shear wave through the test piece; receiving the acoustic waves after they have propagated through the test piece; obtaining acoustic velocities of the surface wave at a non-loaded portion and a loaded portion of the test piece based on the received acoustic waves; evaluating a stress in a surface layer of the test piece based on a difference between the surface wave acoustic velocities at the non-loaded portion and the loaded portion and a predetermined relationship between surface wave acoustic velocities and stresses; obtaining an acoustic velocity of the longitudinal wave at the non-loaded portion based on the received acoustic waves; calculating an acoustic velocity of the shear wave at the loaded portion based on the received acoustic waves and the longitudinal wave acoustic velocity at the non-loaded portion; evaluating an interna

Abstract: In a system for irradiating an ultrasonic beam and imaging the insides of plate-shaped and layer-shaped samples, by using the difference between the sound velocities of a liquid medium and a sample from an ultrasonic transducer to the surface of the sample, the focusing condition is arithmetically operated from the distance between the transducer and the imaging surface which is obtained from the surface echo, and a focal point is set to an arbitrary surface in the sample, thereby correcting a phenomenon such that the focal point of the ultrasonic beam focused into the sample non-linearly moves. Thus, even if the sample is distorted, curved, or inclined, the surface can be imaged at a high resolution and a finer imaging picture can be obtained.