| 摘要 |
PURPOSE:To enable detection of the shape of a crack as well as the presence thereof by moving along the crack two AE signal sensors detecting an AE signal generated from the crack of a body being measured. CONSTITUTION:AE detection sensors S1 and S2 are positioned on the surface of the part of a board 10 in which no cracks are detected, the load is applied in the direction shown by arrows P and Q, and the velocity of propagation V0 is found from the difference in the time required for two sensors S1 and S2 to detect the AE signal generated by the application of the load. Next, the sensor S1 is fixed at the aforesaid position, while the sensor S2 is moved on the surface of the board 10 in the direction shown by the arrows. Since a point where a peak value is found in the result of the measurement by a time difference measuring device 5 during the movement is the position where a crack 9 is present, the depth A1 of the crack 9 is determined from the ratio of the velocity of propagation V1 at this point to the aforesaid V0. Then, the sensor S1 is moved in the direction of an arrow X to points located at prescribed intervals and the respective depth of the crack 9 at these points is determined to be A1...AN from the ratio of VN/V0 at each point. |
