Distributed measurements of strain and temperature using optical fiber: measurement of pipeline shape.
Cementys is proud to demonstrate its new distributed Strain and Temperature monitoring technologies based on Raman and Brillouin Optical Backscattered Time Domain Reflectometries.
Distributed strain and temperature allow measuring the displacement of a pipeline under flexion. To do so, Cementys needs at least 1 meter of fiber laid down either helicoidally or following 3 straight lines at 120° around the pipe. To present both methods, two 13 meters long pipelines are respectively equipped with 3 straight fibers at 120 and with a helicoidal fiber.
2 different interrogation boxes are used, measuring different physical effects: one for the Brillouin effect (sensitive to temperature and strain) and the other for the Raman effect (sensitive only to temperature). By combining information, we can deduce the variation of strain due to mechanical stresses and the absolute temperature of the pipe, with a measurement every 50cm.
The experimental measurements of the amplitude and the direction of bending deflection are done in real-time. Fiber optic is capable of long-range measurements, remote locations can be interrogated (up to 40 miles).
The SensoluxTM® cable containing 4 tight-buffered fibers (2 single-mode and 2 multimode) allows such measurements. Once attached to the pipeline with epoxy glue or equivalent adhesive, all the mechanical strains, and temperature changes are seen by the structure are fully transmitted to the optical fibers, and so detected by the interrogators.
Eventually, this instrumentation gives information on the mechanical strains all along with the structure in real-time.