1996 年 45 巻 1 号 p. 85-88
The precise sizing technique of a fatigue crack height was explained in the previous paper. The accuracy of this method is about 0.2mm, about 1/10th of that of the conventional ultrasonic testing, and it will be effective for fracture mechanics. However, the ultrasonic flaw-detector used was HITACH DT-2200 which is not commercially available. So, a request has been received to use an ultrasonic digital equipment available in the market. In the present study, such an equipment was tried and the accurate results were obtained from the original unrectified wave shape. Since it is a easy technique even for the fracture mechanic engineers, this new technique will be useful for fatigue crack growth tests.