title: Circumferential and longitudinal defect detection using T(0,1) mode excited by thickness shear mode piezoelectric elements.
abstract: Different kinds of defects, such as corrosions, notches and cracks etc, exist in pipes. Mode choice is important since unfortunately not all ultrasonic guided wave modes are suitable for these kinds of defect detection. T(0,1) mode which is non-dispersive is the lowest and fastest torsional mode and most suitable for defect detection in pipes. Two completely different artificial defects including longitudinal and circumferential defects are processed successively in a 4-m-long, 60-mm-OD, 3.5-mm-wall steel pipe. T(0,1) mode at 45 kHz is excited to detect these defects using thickness shear mode piezoelectric elements. Experimental results show that two kinds of defects are detectable using T(0,1) mode. Comparing with longitudinal modes, torsional modes are dominant in pipe inspection for their sensitivities to different kinds of defects.
authors.affiliation: Modern Measurement and Control Technique Lab, College of Mechanical Engineering and Applied Electronics Technology, Beijing University of Technology, Ping Le Yuan 100, Chaoyang District, Beijing 100022, China. LZHBULL@emails.bjut.edu.cn
authors.forename: Zenghua
authors.initials: Z
authors.lastname: Liu
authors.forename: Cunfu
authors.initials: C
authors.lastname: He
authors.forename: Bin
authors.initials: B
authors.lastname: Wu
authors.forename: Xiuyan
authors.initials: X
authors.lastname: Wang
authors.forename: Shiming
authors.initials: S
authors.lastname: Yang