Project – Guided wave technology based pipeline structural monitoring
- Project Description: this project aims to study time reversal method for detecting and localizing structural defects for natural gas pipeline using guided wave technology. This project is currently funded by the NSF Major Research Instrumentation (MRI) program. In the past, this research has been funded through a subcontract from Carnegie Mellon University (CMU) and Concurrent Technology Corporation (CTC) supported by the DOE’s National Energy Technological Lab (NETL). We collaborate with researchers from CMU.
- About Guided Wave Propagation
- Guided waves form as a result of the interaction between harmonic waves propagating in a medium and those medium’s boundaries. Guided waves that form in thin cylindrical shells, or pipes, (which will be referred to as pipe waves) share several characteristics with Lamb waves, which form in thin plates. Lamb waves are commonly used and have been widely studied. Pipe waves are characterized by an infinite number of dispersive longitudinal and torsional modes and a doubly infinite number of flexural modes. The longitudinal and torsional modes are both axisymmetric while each flexural mode exhibits an infinite number of non-axisymmetric circumferential mode orders.
- Many pulse-echo systems use reflections from defects to localize and characterize damage. However, due to the reflections of numerous dispersive modes and the mode conversions that occur at the defects, the received echoes may be difficult to interpret. Figures 1a and 1b show that a 400 kHz Gaussian pulse is significantly distorted after traveling a distance of 1.8 meters in a pipe. This unwanted clutter resulting from multi-modal and dispersive behavior is sometimes referred to as coherent (not random) noise.
To reduce coherent noise, users and developers often use narrowband, low frequency, single mode excitations to suppress unwanted modes and to reduce the influence of dispersion. Transducer geometries and designs can often be exploited for mode selectivity. Unfortunately, these solutions are suboptimal at best, and can often limit the effectiveness of guided wave propagation. - Time reversal focusing is a technique first developed by M. Fink to provide improved spatial and temporal acoustic focusing over conventional methods in inhomogeneous mediums. The process relies on the reciprocity and linearity of a medium and the principle that physical processes, when reversed in time, will result with the time-reversed initial conditions of the original process. Time reversal has been studied for applications in pulse-echo nondestructive testing and imaging, radar, and communications. It has been shown that time reversal is particularly effective in mediums with high concentrations of scatterers.
- Figure-1. (a) 400 kHz Gaussian windowed excitation, (b) Received signal, (c) Time Reversal Focused signal
- Figure-2. Decoded UWB PPM modulated signals transmitted along an experimental pipe specimen. The transmitted information bits are successfully decoded and recovered.
Selected Publications:
- Yujie Ying, Joel Harley, James H. Garrett, Jr., Yuanwei Jin, Irving J. Oppenheim, Jun Shi, and Lucio Soibelman, “Applications of machine learning in pipeline monitoring”, 2011 ASCE International Workshop on Computing in Civil Engineering (Best paper award). [ Full text]
- Y. Jin, Y. Ying, Zhao, “Time reversal data communication on steel pipes – Part II Experimental studies”, SPIE Smart Structures and Non-Destructive Testing, San Diego, CA 2011. [ Full text]
- Y. Jin, D. Zhao, Y. Ying, “Time reversal data communication on steel pipes – Part I Basic principles”, SPIE Smart Structures and Non-Destructive Testing, San Diego, CA 2011. [ Full text]
- Nicholas O’Donoughue, Joel Harley, Jose M.F. Moura, Yuanwei Jin, Irving Oppenheim, Yujie Ying,
Joe States, James Garrett, Lucio Soibelman, Single Antenna Time Reversal of Guided Waves in
Pipes, 157th Acoustical Society of America meeting, Portland, OR, May 2009 (Best Student Paper Award) - Joel Harley, Nicholas O’Donoughue, Joe States, Yujie Ying, James Garrett, Yuanwei Jin, José M.F. Moura, Irving Oppenheim, Lucio Soibelman, Focusing of Ultrasonic Waves in Cylindrical Shells using Time-Reversal, 7th International Workshop on Structural Health Monitoring 2009, Stanford, CA.
