Detection and monitoring of axial cracks in cylindrical structures using torsional wave generated by piezoelectric macro-fiber composite
Lim, Say Ian
Soh, Chee Kiong
Date of Issue2012
Health Monitoring of Structural and Biological Systems (2012 : San Diego, USA)
School of Civil and Environmental Engineering
In cylindrical structures such as pipelines and pressure vessels, cracks are most likely to occur along the longitudinal (axial) direction and they can be fatal to the serviceability of the structures. Unfortunately, the conventional ultrasonic crack detection techniques, which usually use longitudinal wave, are not very sensitive to this type of cracks. This paper focuses on the detection and monitoring of axial cracks in cylindrical structures using torsional wave generated by piezoelectric macro-fiber composite (MFC). The first order torsional wave is a kind of non-dispersive pure shear wave which propagates at a fixed wave speed. Torsional wave is utilized in this work because, intuitively, it is more sensitive to axial cracks than the family of longitudinal waves. Numerical simulation has been performed using ANSYS to show the effectiveness of torsional wave in detecting and monitoring axial cracks. The time of flight (TOF) of the waves is used to determine the crack position, while the crack propagation is monitored by measuring the variation in the crack induced disturbances. Experiments have also been conducted to investigate the feasibility of the proposed method. MFC transducers oriented at 45° against the axis of the specimen are used to generate and receive torsional waves. The experimental results demonstrated that the crack position can be indentified and its growth can be well monitored with the presented approach using torsional wave.
© 2012 Society of Photo-Optical Instrumentation Engineers (SPIE). This paper was published in Proceedings of SPIE-Health Monitoring of Structural and Biological Systems 2012 and is made available as an electronic reprint (preprint) with permission of Society of Photo-Optical Instrumentation Engineers (SPIE). The paper can be found at the following official DOI: [http://dx.doi.org/10.1117/12.914957]. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper is prohibited and is subject to penalties under law.