A glue-free FBG sensor with temperature self-compensation and sensitivity reduction function

Abstract

The utility model relates to a kind of temperature self-compensation and reducing sensitivity function's glue-free FBG sensor, applied in sensor technical field, comprising: sensor base plate, elastomer and fiber grating;Elastomer includes rhombic elastomer and two elastic mounting parts, and rhombic elastomer is sequentially connected by four elastic strips head and tail;The four corners of rhombic elastomer are two first corners and two second corners respectively, which are oppositely arranged;Two elastic mounting parts are connected with two first corners respectively, and two elastic mounting parts are set on sensor base plate;Fiber grating is provided at two second corners.This utility model sensor base plate in the process of temperature rise elastomer L1 section expansion to both sides elongation, fiber grating is compressed, elastomer L2 section and L3 section are heated to expand inward, fiber grating is stretched, so, realize the temperature self-compensation of structure;With simple structure, compensation precision is higher, and long-term use stability is higher.

Description

Technical Field

[0001] This utility model relates to the field of sensor technology, and in particular to a glue-free FBG sensor with temperature self-compensation and desensitization functions. Background Technology

[0002] Fiber Bragg Grating (FBG) sensors are optical sensing elements that measure changes in the wavelength reflected from optical fibers. They have advantages such as simple structure, strong resistance to electromagnetic interference, high sensitivity, long-distance transmission capability, and suitability for harsh environments. They are widely used in structural health monitoring, aerospace, energy equipment, and precision manufacturing.

[0003] Existing FBG sensors typically measure strain or temperature by monitoring changes in the reflected wavelength of a grating. However, in engineering applications, the reflected wavelength of the grating is affected by both strain and temperature; temperature changes introduce additional wavelength drift, thus affecting the accuracy of strain measurement. Therefore, temperature compensation technology has become a critical issue in FBG sensor applications. Existing temperature compensation methods mainly include using the dual-grating differential method, setting a strain-free reference grating, and achieving temperature stress compensation through composite structures made of materials with different coefficients of thermal expansion. However, these methods are structurally complex, have poor compensation accuracy, and lack long-term stability.

[0004] In view of this, there is an urgent need for a glue-free FBG sensor with temperature self-compensation and desensitization functions to solve the above problems. Summary of the Invention

[0005] To help solve the problems existing in the prior art, this utility model provides a glue-free FBG sensor with temperature self-compensation and desensitization function, which adopts the following technical solution: including: sensor base plate, elastomer and fiber optic grating; The elastic body includes a rhomboid elastic body and two elastic mounting parts. The rhomboid elastic body is composed of four elastic strips connected end to end in sequence. The four corners of the rhomboid elastic body are two oppositely arranged first corners and two oppositely arranged second corners. The two elastic mounting parts are respectively connected to the two first corners and are disposed on the sensor base plate. The fiber grating is inserted at the two second corners.

[0006] The elastic mounting part is T-shaped, with one end connected to the first corner and the two ends of the elastic mounting part away from the rhomboid elastic body connected to the sensor base plate.

[0007] The sensor base plate is provided with a metal coating at the connection point with the elastic mounting part, and the sensor base plate and the elastic mounting part are welded together with metal solder.

[0008] The axis of the fiber grating coincides with one diagonal of the rhombic elastomer.

[0009] The two elastic mounting parts are arranged symmetrically about the fiber grating.

[0010] The rhombic elastomer and the fiber optic grating are encapsulated together by welding material.

[0011] The elastomer is integrally molded.

[0012] The surface of the fiber grating is coated with a high-temperature resistant layer.

[0013] The elastomer is made of Kovar alloy.

[0014] The sensor base plate is made of fiberglass.

[0015] The above-described structure of this utility model can achieve the following beneficial effects: During the heating process, the L1 segment of the elastomer in the sensor base plate expands and elongates to both sides, compressing the fiber grating. The L2 and L3 segments of the elastomer expand inward due to heat, stretching the fiber grating. Therefore, in use, temperature self-compensation of the structure can be achieved by adjusting the lengths of the L1, L2, and L3 segments and the angle between L2 and L3. It has the advantages of simple structure, high compensation accuracy, and high stability in long-term use. Under external loads, the rhomboid elastomer can distribute the external force through axial tension and compression within the structure, thereby reducing local stress concentration. Simultaneously, the deformable nature of the rhomboid angles allows the structure to absorb energy within its elastic range. Compared to rectangular or triangular structures, the rhomboid structure exhibits better buckling resistance and self-stabilizing characteristics under compressive, tensile, or torsional loads. The sensor base plate has a high coefficient of thermal expansion, while the rhomboid structure has a low coefficient of thermal expansion; temperature compensation is achieved by adjusting the angle of the rhomboid structure. The sensor base plate and the elastomer, as well as the elastomer and fiber optic grating, are fixed by welding, eliminating the hysteresis effect of adhesive in force transmission and significantly improving the sensor's testing accuracy. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This is a schematic diagram of the structure of this utility model in the self-compensation mode.

[0017] Reference numerals: 1. Sensor base plate; 2. Fiber grating; 3. Rhomboid elastomer; 4. Elastic mounting part. Detailed Implementation

[0018] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0019] It should be noted that the terms "comprising" and "having" and any variations thereof in the specification, claims and accompanying drawings of this utility model are intended to cover non-exclusive inclusion. For example, a process, method, apparatus, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such processes, methods, products or devices.

[0020] The following is in conjunction with the appendix Figure 1-2 The present invention will be described in further detail below.

[0021] Reference Figure 1-2 A glue-free FBG sensor with temperature self-compensation and desensitization functions includes: a sensor base plate 1, an elastomer, and a fiber optic grating 2. The elastomer includes a rhomboid elastomer 3 and two elastic mounting parts 4. The rhomboid elastomer 3 is composed of four elastic strips connected end to end in sequence. The four corners of the rhomboid elastomer 3 are two oppositely arranged first corners and two oppositely arranged second corners. The two elastic mounting parts 4 are respectively connected to the two first corners and are disposed on the sensor base plate 1. Fiber grating 2 is installed at the two second corners.

[0022] Based on the above structure, combined with Figure 2 As shown, during the heating process, the L1 segment of the elastomer in the sensor base plate 1 expands and elongates to both sides, compressing the fiber grating 2. The L2 and L3 segments of the elastomer expand inward due to heat, stretching the fiber grating 2. Therefore, in use, temperature self-compensation of the structure can be achieved by adjusting the lengths of the L1, L2, and L3 segments and the angle between L2 and L3. It has the advantages of simple structure, high compensation accuracy, and high stability in long-term use.

[0023] like Figure 1 and Figure 2As shown, the elastic mounting part 4 is T-shaped. One end of the elastic mounting part 4 is connected to the first corner, and the two ends of the elastic mounting part 4 away from the rhomboid elastic body 3 are connected to the sensor base plate 1. In this way, by setting the T-shaped elastic mounting part 4, one end of the elastic mounting part 4 is connected to the rhomboid elastic body 3, and the other two ends are connected to the sensor base plate 1, which improves the stability of the installation of the rhomboid elastic body 3. The position where the sensor base plate 1 is connected to the elastic mounting part 4 is provided with a metal coating. The elastic body is preferably made of Kovar alloy with a low coefficient of expansion. The sensor base plate 1 and the elastic mounting part 4 are welded together by metal solder. Specifically, it is preferred to fix them to the sensor base plate 1 by welding with solder melted at 200-300°C.

[0024] Further optimization is that, in actual use, the lengths of segments L1, L2, and L3, as well as the angle between L2 and L3, can be adjusted according to requirements to achieve temperature self-compensation of the structure. In this embodiment, the axis of the fiber optic grating 2 coincides with one diagonal of the rhombic elastic body 3, and the two elastic mounting parts 4 are symmetrically arranged with the fiber optic grating 2 as the axis, so that the elastic body compensation on both sides of the fiber optic grating 2 is balanced.

[0025] In this embodiment, the elastomer is preferably integrally formed.

[0026] Further optimization involves a high-temperature resistant coating on the surface of the fiber grating 2, suitable for use at 350°C. The fiber grating 2 is fabricated using a femtosecond point-by-point writing process and is welded and encapsulated with the rhombic elastomer 2 using solder that melts at 300-400°C. The sensor base plate 1 is fixed to the elastomer, and the elastomer is fixed to the fiber grating 2 by welding, eliminating the hysteresis effect in the force transmission process caused by using glue for fixing, and significantly improving the test accuracy of the sensor.

[0027] Further optimization involves adapting the material of the sensor base plate 1 to the application scenario. In this embodiment, the sensor base plate 1 can be made of fiberglass, which is the same material as the wind turbine blade. When applied in wind power installations and performing health checks on the blades, the deformation of both (blade and sensor base plate 1) under force is approximately the same, ensuring the accuracy of the test results.

[0028] In summary, under external loads, the rhomboid elastomer can distribute the external force through axial tension and compression within the structure, thereby reducing local stress concentration. Simultaneously, the deformable nature of the rhomboid angles allows the structure to absorb energy within its elastic range. Compared to rectangular or triangular structures, the rhomboid structure exhibits better buckling resistance and self-stabilizing characteristics under compressive, tensile, or torsional loads. The sensor base plate has a high coefficient of thermal expansion, while the rhomboid structure has a low coefficient of thermal expansion; temperature compensation is achieved by adjusting the angle of the rhomboid structure. The sensor base plate and the elastomer, as well as the elastomer and fiber optic grating, are fixed by welding, eliminating the hysteresis effect of adhesive in force transmission and significantly improving the sensor's testing accuracy. Furthermore, it features high linearity, low sensitivity, and a small temperature compensation coefficient.

[0029] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A glue-free FBG sensor with temperature self-compensation and desensitization functions, characterized in that, include: Sensor base plate (1), elastomer and fiber optic grating (2); The elastomer includes a rhomboid elastomer (3) and two elastic mounting parts (4). The rhomboid elastomer (3) is composed of four elastic strips connected end to end. The four corners of the rhomboid elastomer (3) are two oppositely arranged first corners and two oppositely arranged second corners. The two elastic mounting parts (4) are respectively connected to the two first corners and are disposed on the sensor base plate (1). The fiber grating (2) is installed at the two second corners.

2. The adhesive-free FBG sensor with temperature self-compensation and desensitization function according to claim 1, characterized in that: The elastic mounting part (4) is T-shaped. One end of the elastic mounting part (4) is connected to the first corner, and the two ends of the elastic mounting part (4) away from the rhomboid elastic body (3) are connected to the sensor base plate (1).

3. The adhesive-free FBG sensor with temperature self-compensation and desensitization function according to claim 2, characterized in that: The sensor base plate (1) is provided with a metal coating at the position where it connects with the elastic mounting part (4), and the sensor base plate (1) and the elastic mounting part (4) are welded together by metal solder.

4. The adhesive-free FBG sensor with temperature self-compensation and desensitization function according to claim 2, characterized in that: The axis of the fiber grating (2) coincides with one diagonal of the rhombic elastomer (3).

5. A glue-free FBG sensor with temperature self-compensation and desensitization functions according to claim 4, characterized in that: The two elastic mounting parts (4) are arranged symmetrically about the fiber grating (2).

6. The adhesive-free FBG sensor with temperature self-compensation and desensitization function according to claim 1, characterized in that: The rhombic elastomer (3) and the fiber optic grating (2) are encapsulated by welding material.

7. The adhesive-free FBG sensor with temperature self-compensation and desensitization function according to claim 1, characterized in that: The elastomer is integrally molded.

8. The adhesive-free FBG sensor with temperature self-compensation and desensitization function according to claim 1, characterized in that: The surface of the fiber grating (2) is provided with a high-temperature resistant coating.

9. A glue-free FBG sensor with temperature self-compensation and desensitization functions according to claim 1, characterized in that: The elastomer is made of Kovar alloy.

10. A glue-free FBG sensor with temperature self-compensation and desensitization functions according to claim 1, characterized in that: The sensor base plate (1) is made of fiberglass.

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