CN210833433U - Reinforcing steel bar long-term corrosion monitoring sensor based on Fabry-Perot optical fiber array - Google Patents
Reinforcing steel bar long-term corrosion monitoring sensor based on Fabry-Perot optical fiber array Download PDFInfo
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- CN210833433U CN210833433U CN201922289441.9U CN201922289441U CN210833433U CN 210833433 U CN210833433 U CN 210833433U CN 201922289441 U CN201922289441 U CN 201922289441U CN 210833433 U CN210833433 U CN 210833433U
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Abstract
The utility model provides a reinforcing bar long-term corrosion monitoring sensor based on fabry-perot fiber array belongs to structure health monitoring technical field. The sensor for monitoring long-term corrosion of the steel bar based on the Fabry-Perot optical fiber array comprises a single-mode optical fiber, a steel pocket cover, epoxy resin and a protective hose. The device is based on Fresnel reflection theory and has the steel pocket lid the same with the reinforcing bar composition, through the monitoring of the change in proper order of the optic fibre reflection signal that the steel pocket lid of a plurality of different top end face thicknesses wraps up in the Fabry-Perot optic fibre sensing array, realizes by the harmless, long-term, quantitative monitoring of measuring reinforcing bar corrosion thickness along with the change in time to carry out early warning to the reinforcing bar corrosion state, ensure the safety of major engineering structure. The utility model discloses the cost of manufacture is low, simple structure, and the suitability is strong, has wide application prospect.
Description
Technical Field
The utility model relates to a reinforcing bar long-term corrosion monitoring sensor based on fabry-perot fiber array for concrete structure belongs to structure health monitoring technical field, especially a reinforcing bar long-term corrosion monitoring sensor based on fabry-perot fiber array.
Background
The concrete structure combines the characteristics of high tensile strength of the steel bar and high compressive strength of the concrete, and is the most common and wide-range structural form applied in the civil engineering industry at present. A great deal of facts at home and abroad show that the concrete structure has to be stopped to use, overhauled or dismantled for reconstruction due to the corrosion and the damage of the steel bars, and even a catastrophic accident that the structure collapses suddenly is caused, so that huge economic loss is caused, and a great deal of waste of resource and energy and a great deal of emission of construction waste are caused. The corrosion of the steel bar can be called as the 'concrete durability crisis', and becomes a big disease of civil engineering. Therefore, the steel bar corrosion condition of the structure must be effectively monitored, and the durability of the structure must be accurately judged, so that the safety of important structures is guaranteed, and the rapid and healthy development of national economy is promoted.
Currently, methods for monitoring steel corrosion in concrete structures can be broadly classified into electrochemical methods and non-electrochemical methods. The electrochemical method comprises a half-cell potential method, a linear polarization method, an alternating current impedance method, an electrochemical noise method and the like, and the non-electrochemical method comprises an appearance inspection method, a weight loss method, an ultrasonic method, a core drilling method, an eddy current method, an acoustic emission method and the like. However, these conventional methods have the disadvantages of difficult access to the steel bar to be tested, destructive monitoring to the whole structure, and inability to perform real-time monitoring for a long time. At present, electrochemical corrosion monitoring methods are mainly adopted in engineering, but the electrochemical monitoring is easily interfered by humidity, temperature, external electric fields and the like in the environment.
The optical fiber has the advantages of small diameter, light weight, strong electromagnetic interference resistance, corrosion resistance, high temperature resistance, integration of information sensing and transmission, easiness in integration in a concrete structure body and the like, so that the optical fiber hopefully overcomes the defects of the traditional electric signal probe and has remarkable superiority in monitoring the corrosion of the concrete reinforcement.
Therefore, it is necessary to provide a long-term, real-time and nondestructive optical fiber sensor from a new technical perspective for monitoring the corrosion condition of the reinforcement in the concrete structure, thereby providing an important guarantee for the safe service of the concrete structure.
SUMMERY OF THE UTILITY MODEL
The not enough to prior art, the utility model aims to solve the technical problem that a long-term corrosion monitoring sensor of reinforcing bar based on fabry-perot fiber array is provided, its purpose realizes the long-term real-time quantitative monitoring to reinforcing bar local corrosion degree, realizes the early warning to the structure corrosion situation.
The technical scheme of the utility model:
a steel bar long-term corrosion monitoring sensor based on a Fabry-Perot optical fiber array comprises a single-mode optical fiber 1, a steel pocket cover 2, epoxy resin 3 and a protective hose 4;
the single-mode optical fiber 1 is inserted into the steel pocket cover 2, and the single-mode optical fiber 1 is completely sealed and fixed at the opening of the steel pocket cover 2 by epoxy resin 3;
the single-mode optical fiber 1, the steel pocket cover 2 and the epoxy resin 3 form a Fabry-Perot optical fiber sensing unit, and a plurality of Fabry-Perot optical fiber sensing units are assembled into a Fabry-Perot optical fiber sensing array;
the rest parts of all the single-mode optical fibers 1 which are not inserted into the steel pocket cover 2 are nested and protected by a protective hose 4;
the Fabry-Perot optical fiber sensing units and the protective hoses 4 are fixedly bonded together by epoxy resin 3.
The end face of the single-mode optical fiber 1 is cut and leveled, and the integrity of the end face is ensured as much as possible;
the steel pocket cover 2 is made of common steel bars, the steel pocket cover 2 is hollow, and the inner diameter of the steel pocket cover 2 is larger than the diameter of the single-mode optical fiber 1;
the height of the steel pocket cover 2 is adjusted according to the steel bar to be measured;
the thicknesses of the top end surfaces of a plurality of steel pocket covers 2 in the Fabry-Perot optical fiber sensing array are changed in a step mode, and the specific thickness of the top end surface of each steel pocket cover 2 is adjusted according to the sensitivity of the sensor;
the number of the Fabry-Perot optical fiber sensing units in the Fabry-Perot optical fiber sensing array can be determined according to the diameter of the steel bar to be measured.
The utility model discloses the theory of operation:
the utility model discloses a monitoring method is based on the reflection principle of light, according to the fresnel reflection theory, when light from a medium (former medium) transmit with the boundary surface of another kind of medium, because the refracting index of two kinds of media is different, partly light will be reflected back to former medium, and its reflectivity is for
Wherein R is the total reflectance, RsIs the reflectivity of the s component of the input light, RpAs the reflectivity of the p-component of the input light, n1Is the refractive index of the core of the optical fiber, n2Is the ambient refractive index, θ, outside the fiber endiIs the angle of the input light. Return loss (Return loss) can be expressed as
Return Loss(dB)＝-Clog(1-R)(2)
Where C is a constant, depending on the interface type.
When the fiber ends were wrapped with a steel pocket cover, the environmental medium was initially air (refractive index n)2) As shown in fig. 5 (a). The corrosion product or corrosion medium (refractive index n ') as the corrosion proceeds'2) Penetrating the steel pocket cover top face and contaminating the fiber ends, as shown in fig. 5 (b). According to the formula (1) and the formula (2), the refractive index of the environment outside the end of the optical fiber is from n2Become n'2Resulting in a change in the optical reflection signal.
The utility model discloses a have step nature change between the top end face thickness of a plurality of steel pocket lids, what a plurality of steel pocket lidsThe thickness of the top end face is c1、c2、c3、……、cn(c1<c2<c3<……<cn) Minimum tip face thickness c after corrosion begins1The steel pocket cover is first corroded and penetrated by the top end face, the optical fiber wrapped by the steel pocket cover collects a variable light reflection signal, and the thickness c of the top end face is increased along with the corrosion2、c3、……、cnThe top end face of the steel pocket cover is corroded and penetrated in turn, and the reflected signal of the corresponding wrapped optical fiber is changed in turn. Therefore, the change of the corrosion thickness along with the time can be obtained by monitoring the sequential change of optical fiber reflection signals wrapped by a plurality of steel pocket covers with different top end surface thicknesses in the Fabry-Perot optical fiber sensing array.
Therefore, will the utility model discloses steel bar long-term corrosion monitoring sensor based on fabry-perot fiber array arranges around the steel bar in concrete structure, because the pocket lid of steel is formed by the preparation of the steel bar of the same kind of being surveyed, the composition of the pocket lid of steel promptly is the same with being surveyed the steel bar completely, so, the quantitative monitoring of being surveyed the steel bar corrosion thickness and changing along with time also by the successive change monitoring of a plurality of optic fibre reflection signal in the fabry-perot fiber array and realize.
The utility model has the advantages that:
(1) the utility model discloses be suitable for conceal the position and the position that the people can't see and contact, can bury concrete structure inside, direct contact reinforcing bar arranges, implements direct monitoring to the reinforcing bar.
(2) The utility model discloses a monitoring successively changes of a plurality of optic fibre reflection signal in the Fabry-Perot fiber array, realizes the long-term quantitative monitoring to the corrosion of steel bar thickness, and then realizes the early warning of structure corrosion state.
(3) The utility model discloses can be in real time, online, the steel bar corrosion situation of lossless monitoring structure to implement better management and maintenance to the engineering structure.
(4) The utility model discloses small and exquisite light, anti-interference, strong durability, monitoring process does not need complicated test equipment, and sensitivity is high, the stable performance.
(5) The utility model discloses compare in optical fiber sensor of the same kind, easy preparation, low price, the manufacturing process need not carry out the optical fiber splice, guarantees that the optical fiber performance is more reliable.
(6) The utility model relates to a rationally, simple structure, the suitability is strong, has wide application prospect.
Drawings
FIG. 1 is a schematic structural diagram of a steel bar long-term corrosion monitoring sensor based on a Fabry-Perot fiber array;
FIG. 2 is a sectional view of the A-A section of the steel bar long-term corrosion monitoring sensor based on the Fabry-Perot fiber array of the present invention;
FIG. 3 is a B-B cross section sectional view of the steel bar long-term corrosion monitoring sensor based on the Fabry-Perot fiber array of the present invention;
fig. 4 is a schematic layout diagram of the long-term steel bar corrosion monitoring sensor based on the fabry-perot fiber array applied to the monitoring of the actual concrete structure steel bars;
fig. 5 is a schematic view of the working principle of the present invention, (a) before the top end surface of the steel pocket cover is corroded, and (b) after the top end surface of the steel pocket cover is corroded.
In the figure: 1, a single mode optical fiber; 2, a steel pocket cover; 3, epoxy resin; 4, protecting the hose; 5, a reinforcing steel bar long-term corrosion monitoring sensor based on a Fabry-Perot optical fiber array; 6, reinforcing steel bars; 7, mortar; 8, air; 9 inputting light; 10 corrosion products.
Detailed Description
In order to make the objects, features and advantages of the present invention more obvious and understandable, the drawings in the embodiments of the present invention are combined below to clearly and completely describe the technical solutions in the embodiments of the present invention, and obviously, the embodiments described below are only some embodiments of the present invention, but not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.
As shown in fig. 1 to 3, the utility model provides a reinforcing bar long-term corrosion monitoring sensor based on Fabry-Perot fiber array, which comprises a single mode fiber 1, a steel pocket cover 2, an epoxy resin 3 and a protection hose 4;
the single-mode optical fiber 1 is inserted into the steel pocket cover 2, and the single-mode optical fiber 1 is completely sealed and fixed at the opening of the steel pocket cover 2 by epoxy resin 3;
the single-mode optical fiber 1, the steel pocket cover 2 and the epoxy resin 3 form a Fabry-Perot optical fiber sensing unit, and a plurality of Fabry-Perot optical fiber sensing units are assembled into a Fabry-Perot optical fiber sensing array;
the rest parts of all the single-mode optical fibers 1 which are not inserted into the steel pocket cover 2 are nested and protected by a protective hose 4;
the Fabry-Perot optical fiber sensing units and the protective hoses 4 are bonded and fixed together by epoxy resin 3;
the end face of the single-mode optical fiber 1 is cut and leveled, and the integrity of the end face is ensured as much as possible;
the steel pocket cover 2 is made of common steel bars, the steel pocket cover 2 is hollow, and the inner diameter of the steel pocket cover 2 is larger than the diameter of the single-mode optical fiber 1;
the height of the steel pocket cover 2 is adjusted according to the steel bar to be measured;
the thicknesses of the top end surfaces of a plurality of steel pocket covers 2 in the Fabry-Perot optical fiber sensing array are changed in a step mode, and the specific thickness of the top end surface of each steel pocket cover 2 is adjusted according to the sensitivity of the sensor;
the number of the Fabry-Perot optical fiber sensing units in the Fabry-Perot optical fiber sensing array can be determined according to the diameter of the steel bar to be measured.
The above embodiments are only used to illustrate the technical solution of the present invention, and not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present invention in its corresponding aspects.
Claims (8)
1. A steel bar long-term corrosion monitoring sensor based on a Fabry-Perot optical fiber array is characterized by comprising a single-mode optical fiber (1), a steel pocket cover (2), epoxy resin (3) and a protective hose (4);
the single-mode optical fiber (1) is inserted into the steel pocket cover (2), and the single-mode optical fiber (1) is completely sealed and fixed at the opening of the steel pocket cover (2) by epoxy resin (3);
the single-mode optical fiber (1), the steel pocket cover (2) and the epoxy resin (3) form a Fabry-Perot optical fiber sensing unit, and a plurality of Fabry-Perot optical fiber sensing units are assembled into a Fabry-Perot optical fiber sensing array;
the rest parts of all the single-mode optical fibers (1) which are not inserted into the steel pocket cover (2) are nested and protected by a protective hose (4);
the Fabry-Perot optical fiber sensing units and the protective hoses (4) are bonded and fixed together by epoxy resin (3).
2. The sensor for monitoring long-term corrosion of the steel bar based on the Fabry-Perot optical fiber array according to claim 1, wherein the end face of the single-mode optical fiber (1) is cut and flattened, and the integrity of the end face is ensured as much as possible.
3. The sensor for monitoring long-term corrosion of the steel bar based on the Fabry-Perot optical fiber array according to claim 1 or 2, characterized in that the steel pocket cover (2) is made of steel bar, the steel pocket cover (2) is hollow inside, and the inner diameter of the steel pocket cover (2) is larger than the diameter of the single-mode optical fiber (1); the height of the steel pocket cover (2) is adjusted according to the steel bar to be measured.
4. The reinforcement long-term corrosion monitoring sensor based on the Fabry-Perot optical fiber array is characterized in that the thicknesses of the top end surfaces of a plurality of steel pocket covers (2) in the Fabry-Perot optical fiber sensing array are changed in a step mode, and the specific thickness of the top end surface of each steel pocket cover (2) is adjusted according to the sensitivity of the sensor.
5. The sensor for monitoring long-term corrosion of the steel bar based on the Fabry-Perot optical fiber array according to claim 3, wherein the thicknesses of the top end surfaces of a plurality of steel pocket covers (2) in the Fabry-Perot optical fiber sensing array are changed in a step mode, and the specific thickness of the top end surface of each steel pocket cover (2) is adjusted according to the sensitivity of the sensor.
6. The sensor for monitoring long-term corrosion of the steel bar based on the Fabry-Perot optical fiber array according to claim 1, 2 or 5, wherein the number of Fabry-Perot optical fiber sensing units in the Fabry-Perot optical fiber sensing array is determined according to the diameter of the steel bar to be measured.
7. The sensor for monitoring long-term corrosion of steel bars based on the Fabry-Perot optical fiber array according to claim 3, wherein the number of Fabry-Perot optical fiber sensing units in the Fabry-Perot optical fiber sensing array is determined according to the diameter of the steel bars to be measured.
8. The sensor for monitoring long-term corrosion of steel bars based on the Fabry-Perot optical fiber array according to claim 4, wherein the number of Fabry-Perot optical fiber sensing units in the Fabry-Perot optical fiber sensing array is determined according to the diameter of the steel bars to be measured.
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| CN201922289441.9U CN210833433U (en) | 2019-12-19 | 2019-12-19 | Reinforcing steel bar long-term corrosion monitoring sensor based on Fabry-Perot optical fiber array |
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| CN110849278A (en) * | 2019-12-19 | 2020-02-28 | 大连理工大学 | Reinforcing steel bar long-term corrosion monitoring sensor based on Fabry-Perot optical fiber array |
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| CN110849278A (en) * | 2019-12-19 | 2020-02-28 | 大连理工大学 | Reinforcing steel bar long-term corrosion monitoring sensor based on Fabry-Perot optical fiber array |
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