title: Non-destructive evaluation of depth of surface cracks using ultrasonic frequency analysis.
abstract: Ultrasonic is one of the most common uses of a non-destructive evaluation method for crack detection and characterization. The effectiveness of the acoustic-ultrasound Structural Health Monitoring (SHM) technique for the determination of the depth of the surface crack was presented. A method for ultrasonic sizing of surface cracks combined with the time domain and frequency spectrum was adopted. The ultrasonic frequency spectrum was obtained by Fourier transform technique. A series of test specimens with various depths of surface crack ranging from 1 mm to 8 mm was fabricated. The depth of the surface crack was evaluated using the pulse-echo technique. In this work, three different longitudinal waves with frequencies of 2.25 MHz, 5 MHz and 10 MHz were employed to investigate the effect of frequency on the sizing detection of surface cracks. Reasonable accuracies were achieved with measurement errors less than 7%.
authors.affiliation: Department of Mechanical Engineering, Yuan Ze University, Chung-Li 320, Taiwan. mesch@saturn.yzu.edu.tw.
authors.forename: Shiuh-Chuan
authors.initials: SC
authors.lastname: Her
authors.affiliation: Department of Mechanical Engineering, Yuan Ze University, Chung-Li 320, Taiwan. s852723@mail.yzu.edu.tw.
authors.forename: Sheng-Tung
authors.initials: ST
authors.lastname: Lin