| 摘要 |
PURPOSE:To enable a crack progress length in depth direction to be measured easily and accurately by allowing an ultrasonic sensor to contact a sample and detecting a crack progress length in depth direction of a surface crack according to reflection of ultrasonic wave. CONSTITUTION:A fatigue crack 3 is formed by forming a discharge-machining part 2 at a surface crack sample 1, both edges of the sample 1 are held by a pin 4, and then a load 6 is applied to a tool 5. Then, two ultrasonic sensors 7 are allowed to contact both side surfaces of center of the sample 1, a reflection wave of ultrasonic wave is detected by the crack 3, and then the signal is A/D converted 9 and is output to a computer 10 with a maximum peak of a reflection wave which is detected by a peak detector 8 as a tip in depth direction of the crack 3. The computer 10 instantly calculates the fatigue crack progress characteristics based on the input data and then performs image processing 11 of the crack 3 within the sample 1 for observation on a TV 12, thus enabling a proper measurement to be made and at the same time an amount of work to be reduced and cost to be reduced. |
