| 摘要 |
PURPOSE:To make it possible to perform highly accurate measurement, by arranging an ultrasonic longitudinal wave transmitting probe and a longitudinal wave receiving probe at the close positions on both sides of the opened crack of the surface of a material, and measuring the depth of the crack based on the propagating time of the echo received from the tip of the crack. CONSTITUTION:On both sides of an opened crack 5, which is present on the surface of a material to be tested 6, ultrasonic longitudinal wave probes 1 and 2 are arranged so as to face each other. Longitudinal pulses 3 are transmitted by the longitudinal wave transmitting probe 1. Then echoes 4 are generated as if the tip of the crack 5 were a sound source. Said echoes 4 are received by the longitudinal wave probe 2. The echo is not generated at the part between the surface position 7 of the material to be tested 6 and the echo 8 from the tip of the crack because the wave is shielded by the surface of the crack. Therefore, the echo from the tip of the crack can be clearly observed. In the A scope Figure, the abscissa indicates the elapsed time, and the ordinate indicates the amplitude of the echo. |
