Fiber grating sensor

Abstract

The utility model provides a fiber grating sensor, which belongs to the technical field of sensors and comprises a mounting element, a transition element, an adapter substitute, an elastic meter and an optical fiber. The mounting element is provided with a containing groove and a grating, and the lower side of the containing groove is close to the centroid of the mounting element; the transition element is fixedly mounted on one side of the mounting element, and a through hole is formed in the transition element; the adapter is mounted at one end, far away from the mounting element, of the transition element; a connecting hole and a lead-out hole are formed in the adapter; the elastic measuring meter is fixedly mounted on the adapter; an elastic piece and a lead are arranged on the elastic measuring piece; the optical fiber is installed in the containing groove, one end of the optical fiber is located at the end, away from the transition element, of the installation element, and the other end sequentially penetrates through the through hole and the connecting hole and penetrates out of the adapter from the leading-out hole. According to the fiber grating sensor provided by the utility model, the monitoring accuracy of the sensor is improved, and the sensor can monitor large deformation.

Description

Technical Field

[0001] The utility model belongs to the technical field of sensors, and more specifically, relates to a fiber Bragg grating sensor. Background Art

[0002] With the gradual aging of important building structures and the continuous development of structural intelligence, to ensure the structural safety and reliability and reduce engineering risks, the importance of structural health monitoring has become increasingly prominent. Fiber Bragg grating sensors have become one of the main technical means for current structural health monitoring due to their excellent characteristics. They have advantages such as good durability and anti-electromagnetic interference and have been widely used in various fields. The monitoring principle of a fiber Bragg grating strain gauge is to install it on the surface of a component. When the component is loaded, the small deformation (elongation or shortening) generated on the surface will cause the sensitive grating of the fiber Bragg grating strain gauge to deform accordingly. Then, the deformation of the component is deduced through the deformation of the grating to achieve the effect of health monitoring. Because of its advantages such as good durability, anti-electromagnetic interference, and the ability to achieve quasi-distributed monitoring, it is widely used in structural health monitoring projects. Currently, the fiber Bragg grating strain gauge adheres the optical fiber on the surface, and there is an error between the deformation of the component and the deformation of the optical fiber, resulting in low monitoring accuracy; at the same time, it is difficult for the fiber Bragg grating strain gauge to monitor large deformations. Summary of the Utility Model

[0003] The purpose of the utility model is to provide a fiber Bragg grating sensor to solve the technical problems existing in the prior art, such as the low monitoring accuracy of the fiber Bragg grating strain gauge and the difficulty in monitoring large deformations.

[0004] To achieve the above purpose, the technical solution adopted by the utility model is: providing a fiber Bragg grating sensor, including:

[0005] An installation element, having a receiving groove penetrating along the length direction at the upper end and a grating located on one side of the receiving groove; the lower side of the receiving groove is arranged near the centroid of the installation element;

[0006] A transition element, fixedly installed on one side of the installation element; a through hole corresponding to the receiving groove is provided on the transition element;

[0007] A conversion joint, installed at one end of the transition element away from the installation element; a connection hole corresponding to the through hole is provided on the conversion joint, and a lead-out hole communicating with the connection hole is provided on the outer side surface of the conversion joint;

[0008] An elastic measuring instrument, fixedly installed at one end of the conversion joint away from the transition element; the elastic measuring member has an elastic member and a lead connected to the elastic member;

[0009] An optical fiber is installed in the accommodation groove; one end of the optical fiber is located at one end of the installation element away from the transition element, and the other end passes through the through hole, the connection hole in sequence, and exits the conversion joint from the lead-out hole.

[0010] In a possible implementation manner, a connecting post is provided at the end of the installation element, and an external thread section is provided on the outer side surface of the connecting post; the accommodation groove penetrates through the connecting post; an internal thread section connected to the external thread section is provided on the inner wall of the through hole.

[0011] In a possible implementation manner, a connecting shaft is provided at one end of the transition element away from the installation element, and a through hole coaxial with the through hole is provided on the connecting shaft; an external thread section connected to the internal thread section is provided on the outer side surface of the shaft section of the connecting shaft close to the transition element, an external thread section is provided on the outer side surface of the shaft section of the connecting shaft away from the transition element, and an internal thread section connected to the shaft section of the connecting shaft away from the transition element is provided in the connection hole.

[0012] In a possible implementation manner, the connecting shaft is a stepped shaft, an external thread section is provided on the outer side surface of the shaft section of the connecting shaft away from the transition element, and an internal thread section connected to the shaft section of the connecting shaft away from the transition element is provided in the connection hole.

[0013] In a possible implementation manner, a first screw hole arranged radially is provided on the outer side surface of the shaft section of the connecting shaft away from the transition element, an installation hole corresponding to the first screw hole is provided on the outer side surface of the conversion joint; a bolt for passing through the installation hole and being threadedly connected to the first screw hole is further provided on the conversion joint.

[0014] In a possible implementation manner, a second screw hole is provided on one side of the conversion joint away from the transition element, and a screw rod threadedly connected to the second screw hole is provided at the end of the elastic measuring instrument.

[0015] In a possible implementation manner, an installation surface for fitting and installing with the outer side surface of the optical fiber is provided on the lower side of the accommodation groove, and the center line of the installation surface is collinear with the central axis of the installation element.

[0016] In a possible implementation manner, the installation element is a solid round steel, the accommodation groove extends from the outer side surface of the solid round steel radially towards the center of the solid round steel; both the transition element and the conversion joint are hollow round steels.

[0017] In a possible implementation, the elastic gauge includes a housing, and a strip-shaped installation cavity is provided inside the housing; one end of the housing is fixedly connected to the adapter, and an outlet communicating with the installation cavity is provided at the other end; the number of elastic members is two, and they are arranged at intervals in the installation cavity, and the two elastic members are arranged along the length direction of the installation cavity; one end of the lead wire is located in the installation cavity and is connected to the two elastic members, and the other end passes through the outlet and is located outside the housing.

[0018] In a possible implementation, the lead-out hole is an inclined hole, and an anti-abrasion layer is provided on the inner wall of the lead-out hole.

[0019] The beneficial effects of the fiber Bragg grating sensor provided by the present utility model are as follows: Compared with the prior art, when installing the fiber Bragg grating sensor of the present utility model, the installation element, the transition element, the adapter, and the elastic gauge are docked and installed in sequence, and the optical fiber is disposed in the receiving groove and passes through the through hole and the connection hole and exits from the lead-out hole; the optical fiber is installed in the receiving groove of the installation component, and the optical fiber is located on the bottom surface of the receiving groove, so that the optical fiber is close to the centroid of the installation component, reducing the distance between the centroid of the installation component and the optical fiber, so that when the installation component is deformed by force, the deformation of the optical fiber is relatively consistent, improving the monitoring accuracy of the sensor; and when the installation component undergoes a large deformation, the acting force generated by the deformation acts on the elastic gauge through the transition element and the adapter, and the deformation displacement is measured by means of the elastic member and the lead wire, thereby completing the monitoring of the large deformation; in this way, when the installation component is deformed by force, the deformation of the optical fiber is relatively consistent, improving the monitoring accuracy of the sensor, and also enabling the sensor to monitor large deformations. Description of the Drawings

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the following drawings are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0021] Figure 1 It is a schematic structural diagram of the installation element provided by the embodiment of the present utility model;

[0022] Figure 2 It is a schematic structural diagram of the transition element provided by the embodiment of the present utility model;

[0023] Figure 3 It is a schematic structural diagram of the adapter provided by the embodiment of the present utility model;

[0024] Figure 4The structural schematic diagram of the elastic measuring instrument provided by the embodiment of the utility model;

[0025] Figure 5 The structural schematic diagram of the fiber Bragg grating sensor provided by the embodiment of the utility model.

[0026] Among them, each reference numeral in the figure:

[0027] 1, mounting element; 11, receiving groove; 12, grating; 13, connecting column; 2, transition element; 21, through hole; 22, connecting shaft; 23, through hole; 24, first screw hole; 3, adapter; 31, connecting hole; 32, lead-out hole; 33, mounting hole; 34, bolt; 35, second screw hole; 4, elastic measuring instrument; 41, elastic member; 42, lead wire; 43, screw; 44, housing; 45, mounting cavity; 46, outlet; 5, optical fiber. Detailed implementation manners

[0028] In order to make the technical problems, technical solutions and beneficial effects to be solved by the utility model clearer, the following further details the utility model with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the utility model and are not used to limit the utility model.

[0029] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0030] It should be understood that the orientation or positional relationship indicated by the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the utility model.

[0031] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the utility model, "a plurality of" means two or more unless otherwise specifically defined.

[0032] Please refer to Figures 1 to 5, the fiber Bragg grating sensor provided by the present utility model will be described hereinafter. A fiber Bragg grating sensor includes a mounting element 1, a transition element 2, a conversion joint 3, an elastic measuring gauge 4 and an optical fiber 5; the upper end of the mounting element 1 is provided with a receiving groove 11 penetrating along the length direction and a grating 12 located on one side of the receiving groove 11; the lower side of the receiving groove 11 is arranged close to the centroid of the mounting element 1; the transition element 2 is fixedly mounted on one side of the mounting element 1; the transition element 2 is provided with a through hole 21 corresponding to the receiving groove 11; the conversion joint 3 is mounted at one end of the transition element 2 away from the mounting element 1; the conversion joint 3 is provided with a connection hole 31 corresponding to the through hole 21, and a lead-out hole 32 communicating with the connection hole 31 is arranged on the outer side surface of the conversion joint 3; the elastic measuring gauge 4 is fixedly mounted at one end of the conversion joint 3 away from the transition element 2; the elastic measuring member has an elastic member 41 and a lead 42 connected to the elastic member 41; the optical fiber 5 is mounted in the receiving groove 11; one end of the optical fiber 5 is located at one end of the mounting element 1 away from the transition element 2, and the other end passes through the through hole 21, the connection hole 31 in sequence and exits from the lead-out hole 32 of the conversion joint 3.

[0033] Compared with the prior art, when the fiber Bragg grating sensor provided by the present utility model is installed, the mounting element 1, the transition element 2, the conversion joint 3 and the elastic measuring gauge 4 are butted and installed in sequence, and the optical fiber 5 is inserted into the receiving groove 11 and passes through the through hole 21 and the connection hole 31 and exits from the lead-out hole 32; the optical fiber 5 is installed in the receiving groove 11 of the mounting component, and the optical fiber 5 is located on the bottom surface of the receiving groove 11, so that the optical fiber 5 is close to the centroid of the mounting component, reducing the distance between the centroid of the mounting component and the optical fiber 5. Therefore, when the mounting component is deformed by force, the deformation of the optical fiber 5 is relatively consistent, improving the monitoring accuracy of the sensor; and when the mounting component undergoes a large deformation, the acting force generated by the deformation acts on the elastic measuring gauge 4 through the transition element 2 and the conversion joint 3, and the deformation displacement is measured by means of the elastic member 41 and the lead 42, thereby completing the monitoring of the large deformation; in this way, when the mounting component is deformed by force, the deformation of the optical fiber 5 is relatively consistent, improving the monitoring accuracy of the sensor, and enabling the sensor to monitor large deformations.

[0034] Please refer to Figure 1 and Figure 2, as a specific embodiment of the fiber Bragg grating sensor provided by the present utility model, the end of the mounting element 1 is provided with a connecting column 13, and an external thread section is provided on the outer side surface of the connecting column 13; the receiving groove 11 penetrates through the connecting column 13; an internal thread section connected to the external thread section is provided on the inner wall of the through hole 21; when connecting the transition element 2 with the mounting element 1, the internal thread section on the inner wall of the through hole 21 in the transition element 2 is in mating connection with the external thread section on the connecting column 13, so that the mounting element 1 and the transition element 2 are firmly mounted together by means of threaded connection. At the same time, the receiving groove 11 is provided to penetrate through the connecting column 13, so that the optical fiber 5 will not be interfered or blocked by the connecting column 13, and the optical fiber 5 passes through the connecting column 13 in the receiving groove 11 and smoothly enters the through hole 21 in the transition element 2.

[0035] Please refer to Figure 2 , as a specific embodiment of the fiber Bragg grating sensor provided by the present utility model, one end of the transition element 2 away from the mounting element 1 is provided with a connecting shaft 22, and a through hole 23 coaxial with the through hole 21 is provided on the connecting shaft 22; an external thread section connected to the internal thread section is provided on the outer side surface of the shaft section of the connecting shaft 22 close to the transition element 2, an external thread section is provided on the outer side surface of the shaft section of the connecting shaft 22 away from the transition element 2, and an internal thread section connected to the shaft section of the connecting shaft 22 away from the transition element 2 is provided in the connecting hole 31; a connecting shaft 22 is provided at one end of the transition element 2 away from the mounting element 1, and an external thread section is provided on the connecting shaft 22, so the connecting shaft 22 is connected to the transition element 2 by means of threaded connection, and a part of the connecting shaft 22 enters the through hole 21, and the other part is located outside the transition element 2; when installing the conversion joint 3, the internal thread section in the connecting hole 31 is fixedly connected to a section of the connecting shaft 22 located outside the transition element 2.

[0036] Please refer to 2, as a specific embodiment of the fiber Bragg grating sensor provided by the present utility model, the connecting shaft 22 is a stepped shaft, an external thread section is provided on the outer side surface of the shaft section of the connecting shaft 22 away from the transition element 2, and an internal thread section connected to the shaft section of the connecting shaft 22 away from the transition element 2 is provided in the connecting hole 31; the connecting shaft 22 is a stepped shaft, and an external thread section is provided on the outer side surface of the stepped shaft. The stepped shaft has two shaft sections, which are respectively connected to the transition element 2 and the conversion joint 3.

[0037] Please refer to Figure 2 、 Figure 3 and Figure 5, as a specific implementation of the fiber grating sensor provided by the present utility model, a first screw hole 24 arranged radially is provided on the outer side surface of the shaft section of the connecting shaft 22 away from the transition element 2, and a mounting hole 33 corresponding to the first screw hole 24 is provided on the outer side surface of the adapter 3; a bolt 34 for passing through the mounting hole 33 and being threadedly connected to the first screw hole 24 is further provided on the adapter 3; after the adapter 3 is connected to the connecting shaft 22, the mounting hole 33 on the adapter 3 is coaxially aligned with the first screw hole 24 on the connecting shaft 22, and then the bolt 34 is used to pass through the mounting hole 33 and be threadedly connected to the first screw hole 24, thereby fixedly connecting the adapter 3 and the connecting shaft 22 together. In this way, the situation that the adapter 3 rotates excessively during the installation process can be effectively prevented, and the installation between the adapter 3 and the transition assembly is more accurate and reliable.

[0038] Please refer to Figures 3 to 5 , as a specific implementation of the fiber grating sensor provided by the present utility model, a second screw hole 35 is provided on the side of the adapter 3 away from the transition element 2, and a screw rod 43 threadedly connected to the second screw hole 35 is provided at the end of the elastic measuring instrument 4; when installing the elastic measuring instrument 4 on the adapter 3, the screw rod 43 on the outer end of the elastic measuring instrument 4 is cooperatively connected with the second screw hole 35 on the adapter 3, and the elastic measuring instrument 4 and the adapter 3 are firmly and conveniently installed together by means of threaded connection.

[0039] Please refer to Figure 1 and Figure 5 , as a specific implementation of the fiber grating sensor provided by the present utility model, a mounting surface for cooperatively installing with the outer side surface of the optical fiber 5 is provided on the lower side of the accommodating groove 11, and the center line of the mounting surface is collinear with the central axis of the mounting element 1; the outer contour of the mounting surface is adapted to the outer contour of the optical fiber 5, so after the optical fiber 5 is installed into the accommodating groove 11, it is cooperatively installed into the mounting surface, making the installation of the optical fiber 5 stable and accurate. At the same time, the central axis of the mounting surface is collinear with the central axis of the mounting assembly, so that the light installed in the mounting surface is also collinear with the axis of the mounting assembly, ensuring that the deformation size of the mounting assembly is more consistent with the deformation size of the optical fiber 5, and further making the monitoring of the sensor more accurate.

[0040] Please refer to Figures 1 to 5 , as a specific implementation of the fiber grating sensor provided by the present utility model, the mounting element 1 is a solid round steel, and the accommodating groove 11 extends radially from the outer side surface of the solid round steel towards the center of the solid round steel; both the transition element 2 and the adapter 3 are hollow round steels.

[0041] Please refer to Figure 5 and Figure 4, as a specific implementation of the fiber Bragg grating sensor provided by the present utility model, the elastic measuring gauge 4 includes a housing 44, and a long strip-shaped installation cavity 45 is provided inside the housing 44; one end of the housing 44 is fixedly connected to the conversion joint 3, and the other end is provided with an outlet 46 communicating with the installation cavity 45; the number of elastic members 41 is two, and they are arranged at intervals in the installation cavity 45, and the two elastic members 41 are arranged along the length direction of the installation cavity 45; one end of the lead wire 42 is located in the so-called installation cavity 45 and is connected to the two elastic members 41, and the other end passes through the outlet 46 and is located outside the housing 44; the housing 44 is the external structure of the elastic measuring gauge 4, and a long strip-shaped installation cavity 45 is provided inside the housing 44, and the two elastic members 41 are both installed in the installation cavity 45, and the deformation direction of the elastic member 41 is consistent with the length direction of the installation cavity 45, and the two elastic members 41 are arranged in parallel at intervals; and the lead wire 42 is installed at the position of the outlet 46 of the housing 44, one end of the lead wire 42 is connected to the two elastic members 41 at the same time, and the other end passes through the outlet 46 and is used to transmit and measure displacement. There are two elastic members 41, so that the force during the monitoring process is more uniform and the monitoring is more accurate. The elastic member 41 is a spring.

[0042] Connect the spring for measuring displacement at the conversion joint 3 and fix the lead wire. The principle of measuring displacement is as follows:

[0043]

[0044] Among them, is the measured displacement, is the spring coefficient, is the force measured by the sensor, which is calculated through the strain transfer rate or wavelength transformation. The cooperation of strain measurement and displacement measurement can not only realize data self-check, effectively identify accurate data, improve monitoring accuracy, but also reduce the sensor assembly cost and the engineering installation cost.

[0045] The calculation method of is to use the change of the central reflection wavelength of the fiber Bragg grating (hereinafter represented by

[0046]

[0047] In the formula is the axial strain of the optical fiber, and its magnitude is equal to the strain of the cubic support column;

[0048] is the central reflection wavelength of the fiber Bragg grating;

[0049] is the change of the central reflection wavelength of the fiber Bragg grating;

[0050] is called the effective elasto-optic coefficient, , 、 are elasto-optic constants, that is, the longitudinal and transverse refractive index changes caused by longitudinal strain respectively, is the Poisson's ratio.

[0051] Please refer to Figure 3 and Figure 5 , as a specific implementation manner of the fiber grating sensor provided by the present utility model, the lead-out hole 32 is an inclined hole, and an anti-abrasion layer is provided on the inner wall of the lead-out hole 32; the optical fiber can smoothly pass through the adapter 3 by means of the inclined hole; and the optical fiber 5 is protected to a certain extent by means of the anti-abrasion layer.

[0052] The above are only the preferred embodiments of the present utility model, and are not intended to limit the present utility model. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present utility model shall be included in the protection scope of the present utility model.

Claims

1. An optical fiber grating sensor, characterized in that, Comprising: An installation element, with a receiving groove penetrating along the length direction at the upper end and a grating located on one side of the receiving groove; The lower side of the receiving groove is arranged close to the centroid of the installation element; A transition element, fixedly installed on one side of the installation element; a through hole corresponding to the receiving groove is provided on the transition element; A conversion joint, installed at one end of the transition element away from the installation element; a connection hole corresponding to the through hole is provided on the conversion joint, and a lead-out hole communicating with the connection hole is provided on the outer side surface of the conversion joint; An elastic measuring instrument, fixedly installed at one end of the conversion joint away from the transition element; an elastic element and a lead wire connected to the elastic element are provided on the elastic measuring instrument; An optical fiber, installed in the receiving groove; one end of the optical fiber is located at one end of the installation element away from the transition element, and the other end sequentially passes through the through hole, the connection hole, and exits the conversion joint from the lead-out hole.

2. The fiber Bragg grating sensor according to claim 1, characterized in that, A connection post is provided at the end of the installation element, and an external thread section is provided on the outer side surface of the connection post; the receiving groove penetrates the connection post; an internal thread section connected to the external thread section is provided on the inner wall of the through hole.

3. The fiber Bragg grating sensor according to claim 2, characterized in that, A connection shaft is provided at one end of the transition element away from the installation element, and a through hole coaxially arranged with the through hole is provided on the connection shaft; an external thread section connected to the internal thread section is provided on the outer side surface of the shaft section of the connection shaft close to the transition element, an external thread section is provided on the outer side surface of the shaft section of the connection shaft away from the transition element, and an internal thread section connected to the shaft section of the connection shaft away from the transition element is provided in the connection hole.

4. The fiber Bragg grating sensor according to claim 3, wherein The connection shaft is a stepped shaft, an external thread section is provided on the outer side surface of the shaft section of the connection shaft away from the transition element, and an internal thread section connected to the shaft section of the connection shaft away from the transition element is provided in the connection hole.

5. The fiber Bragg grating sensor according to claim 3, wherein, A first screw hole arranged radially is provided on the outer side surface of the shaft section of the connection shaft away from the transition element, and a mounting hole corresponding to the first screw hole is provided on the outer side surface of the conversion joint; a bolt for passing through the mounting hole and threadedly connecting with the first screw hole is further provided on the conversion joint.

6. The fiber Bragg grating sensor according to claim 3, wherein, A second screw hole is provided on one side of the conversion joint away from the transition element, and a screw rod threadedly connected to the second screw hole is provided at the end of the elastic measuring instrument.

7. The fiber Bragg grating sensor according to claim 1, wherein An installation surface for fitting and installing with the outer side surface of the optical fiber is provided on the lower side of the receiving groove, and the center line of the installation surface is collinear with the central axis of the installation element.

8. The fiber Bragg grating sensor according to claim 6, wherein, The installation element is a solid round steel, and the receiving groove extends radially from the outer side surface of the solid round steel towards the center of the solid round steel; both the transition element and the conversion joint are hollow round steels.

9. The fiber Bragg grating sensor according to claim 1, wherein, The elastic measuring instrument includes a housing, and a long strip-shaped installation cavity is provided inside the housing; one end of the housing is fixedly connected to the conversion joint, and the other end is provided with an outlet communicating with the installation cavity; the number of the elastic members is two, and they are arranged at intervals in the installation cavity, and the two elastic members are arranged along the length direction of the installation cavity; one end of the lead wire is located in the installation cavity and is connected to the two elastic members, and the other end passes through the outlet and is located outside the housing.

10. The fiber Bragg grating sensor according to claim 1, characterized in that, The lead-out hole is an inclined hole, and an anti-wear layer is provided on the inner wall of the lead-out hole.

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