MULTIPLEXED OPTICAL FIBER CRACK SENSOR

• Main Author: JOHNSTON, ROBERT T
• Format: Patent
• Language: English; French; German
• Published: 18.12.2013
• Subjects: BLASTING; ENGINE PLANTS IN GENERAL; HEATING; INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIRCHEMICAL OR PHYSICAL PROPERTIES; LIGHTING; MACHINES OR ENGINES IN GENERAL; MEASURING; MECHANICAL ENGINEERING; NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAMTURBINES; PHYSICS; STEAM ENGINES; TESTING; TESTING STATIC OR DYNAMIC BALANCE OF MACHINES ORSTRUCTURES; TESTING STRUCTURES OR APPARATUS NOT OTHERWISE PROVIDED FOR; WEAPONS

An optical fiber crack detector that includes a plurality of FBG sensors positioned within one or more fibers that are operable to reflect a defined wavelength of an optical input beam. The crack detector includes a light source for generating the optical input beam that propagates down the optical fiber and interacts with the FBG sensors. A wavelength of the optical beam that is reflected by the FBG sensors is detected, and if a crack in the component damages the fiber between an FBG sensor and the detector circuit, where one or more of the reflected signals are not received, the detector knows that a crack has occurred. By strategically placing a plurality of the FBG sensors along the fiber, a crack that damages the fiber in multiple locations between multiple FBG sensors, or in multiple fibers, can provide an indication of the length of the crack.