Using time reversal to detect pipeline cracks

The agenda for an upcoming meeting of the Acoustical Society of America includes a session on a potential new technology to detect cracks in natural gas pipelines. The meeting is scheduled for May 18-22 in Portland.

Nicholas O’Donoughue of Carnegie Mellon University is researching how to monitor buried pipelines using embedded, ultrasonic detectors according to ScienceDaily, which based its story upon material from the American Institute of Physics.

His talk is entitled “Detection of structural faults in pipelines with time reversal.”
Time reversal involves patterns created by dispersion of sound waves that can be analyzed to detect changes in a material.

O’Donoughe’s idea is to send an ultrasonic signal from one detector through the walls of the pipeline to another detector. Ideally, the signal would retrace its route and bounce back to the first detector.

He believes a crack or corrosion would keep the sound waves from retracing their path. Any structural imperfections in a pipeline are expected to disturb the forward and backward waves.

The ScienceDaily story can be found at http://www.sciencedaily.com/releases/2009/04/090426094559.htm