Optical fiber corrosion sensor based on surface plasma resonance technology

Abstract

The invention belongs to the field of structural health monitoring, and discloses an optical fiber corrosion sensor based on a surface plasma resonance technology. The optical fiber corrosion sensor comprises a multimode optical fiber, a single-mode optical fiber, wherein the multimode optical fiber comprises a fiber core, a cladding and a coating layer; and the single-mode optical fiber comprisesa fiber core, a cladding, a silver thin film and an iron thin film. The optical fiber corrosion sensor realizes corrosion monitoring of a reinforcing steel bar based on a plasma resonance technology.The refractive index of media around the single-mode optical fiber can be changed after the iron thin film with the main components similar to those of the steel bar is corroded, plasmas between thesilver thin film and the iron thin film of the single-mode optical fiber are highly sensitive to changes of the refractive index of the media around the single-mode optical fiber, and the corrosion condition of the reinforcing steel bar is indirectly monitored by monitoring the external refractive index of the single-mode optical fiber. The optical fiber corrosion sensor is simple in structure, low in manufacturing cost, high in sensitivity and high in measurement precision, can effectively realize nondestructive, real-time and accurate measurement of the corrosion condition of the reinforcingsteel bar in the reinforced concrete structure, has a wide application prospect in the field of steel corrosion monitoring, and is suitable for popularization.

Description

technical field [0001] The invention relates to an optical fiber corrosion sensor based on surface plasmon resonance technology, which belongs to the field of structural health monitoring, and is especially used for corrosion monitoring of steel bars in reinforced concrete structures. Background technique [0002] Reinforced concrete structures combine the advantages of high tensile strength of steel bars and high compressive strength of concrete, and are currently the most widely used structural forms in civil engineering. However, the corrosion of steel bars is the most difficult problem faced by reinforced concrete structures. Corrosion of steel bars can not only weaken its own cross-sectional area and reduce the bearing capacity of steel bars, but also reduce the binding force of concrete and affect the cooperative performance of the two. In addition, the volume expansion of steel bars after corrosion causes cracking or even falling off of the concrete, which ultimately...

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Problems solved by technology

These methods are difficult to achieve direct contact with steel bars, and there are great uncertainties in the measurement results, and it is impossible to accurately and real-time monitor the corrosion state of steel bars

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