| 摘要 |
PURPOSE:To correctly measure the conditions of cracks by taking into consideration the temperaure dependency of the velocity of propagation of ultrasonic waves and compensating the temperature variation of cracked parts. CONSTITUTION:When an actuator A is operated, a crack C propagate into the interior of a crack test piece 1 from a cut 1a. A trigger signal provided by a synchronizing signal circuit 12 causes the oscillator 2 of a vibrator 4 to emit an ultrasonic wave at a predetermined angle. The ultrasonic wave is reflected by one end C1 of the crack C, then is received by a receiver 3, and then applied to a CPU16 through a high speed response type head amplifier 9, a waveform shaping circuit 10 and a ratch circuit 11. A signal provided by a temperature sensor 19 is applied to an interface 21 for the temperature compensation of a signal corresponding to a velocity of propagation of ultrasonic wave from ROM20. The time of propagation of the ultrasonic wave, the temperature-compensated velocity of propagation and the position of the end C1 of the crack C can correctly be measured by means of the CPU16. |
