OPTICAL FIBER ACOUSTIC EMISSION METHOD FOR DETERMINING PLASTIC DEFORMATIONS OF LARGE ENGINEERING STRUCTURES

摘要

FIELD: physics.SUBSTANCE: signal of acoustic emission (AE) is generated by a brittle hardening glue, and is recorded using a multimode fibre optic distributed sensor. The glue is applied to an optical fibre, which serves as a distributed sensing element (DSE), when it is mounted on an engineering structure. After hardening, the glue becomes brittle and not only fixes optical fibre on the object, but also generates the AE signal when it is cracking, in case of plastic deformation of the controlled object (engineering structure). This method has a very high sensitivity, since the AE signal appears in the immediate vicinity of the sensor (DSE). Therefore, an acoustic-emission wave, which is practically not weakened, is almost completely transformed into an optical wave, and then into an electrical signal. The distributed sensor (DSE) glued to the engineering structure registers any plastic deformation, which leads to cracking of the brittle layer - hardened glue applied directly to fibre optics, for its entire length.EFFECT: increasing the sensitivity while reducing hardware costs, expanding the frequency spectrum of recorded signals, the ability to detect areas at an early stage, on which the destruction of the controlled object can occur, the ability to continuous remote monitoring.1 dwg