Fundamental study on ultrasonic measurement system to detect penetration of boulders using auto-correlation analysis

Generally, in the estimation of damage and the investigation of the size of every concrete artificial structure thing, nondestructive test is used. An ultrasonic method and an elastic impact wave method are mentioned to the typical thing of a nondestructive test method. The authors have developed a new ultrasonic method by using ultrasonic wave of the chirp signal and auto-correlation analysis. In this paper, the experiment is separated Pattern 1 and Pattern 2. In Pattern 1, ultrasonic transfer characteristics were investigated for concrete blocks. It was confirmed that the frequency components of 40 ∼ 60 kHz had a good permeability with each thickness of concrete blocks. In Pattern 2, experiment of receiving the reflection wave was carried out using concrete block with width of 900 mm and ultrasonic wave of the chirp signal. Reflection wave was detected in the down chirp signal from 50 kHz to 40 kHz. And the length of concrete block was calculated using auto-correlation was set to 898.156 mm. Like this, the good result that has little error could get it using this system.