Fiber bragg grating sensor for wind turbine generator foundation flange bolt

Abstract

The utility model discloses a fiber bragg grating sensor for a wind turbine generator foundation flange bolt, which comprises a gasket, a fiber bragg grating temperature sensor, a fiber bragg grating stress sensor, an optical fiber, an optical fiber connector and an optical fiber adapter, the fiber bragg grating temperature sensor and the fiber bragg grating stress sensor are connected and adhered to the outer circumferential surface of the gasket through optical fibers, the optical fibers are wound on the outer circumferential surface of the gasket, the two ends of the optical fibers are connected with the optical fiber adapter through the optical fiber connector, and the gasket sleeves the bolt and is located below the nut; according to the utility model, the stress connection state of the bolt in the fastening and service process can be accurately and reliably measured and monitored.

Description

Technical Field

[0001] This utility model belongs to the field of bolt structure safety detection technology, specifically relating to a fiber optic grating sensor for wind turbine foundation flange bolts. Background Technology

[0002] Bolted connections are a common connection method in modern steel structures. Due to their simple structure, high efficiency, low cost, and convenient and reliable connection, they are widely used in various fields such as machinery, bridges, and wind power generation. Most bolts require pre-tightening during installation. This operation enhances the reliability, tightness, and anti-loosening ability of the bolted connection, thereby improving the quality of the bolted connection. The quality of bolted connections directly affects the safe and reliable operation of wind power equipment. However, in reality, the quality of bolted connections is affected by operating conditions and human factors, making it difficult to guarantee that they meet operational requirements. During subsequent equipment maintenance, regular manual inspection of bolted connections is often required. However, the number of bolts used in general equipment is large, and some installation locations are difficult to access, making it difficult for inspectors to detect and promptly resolve problems with the bolted connections. Therefore, accurate and reliable measurement and monitoring of the stress state of bolted connections during tightening and service is necessary. Utility Model Content

[0003] This utility model provides a fiber optic grating sensor for wind turbine foundation flange bolts, which includes a gasket, a fiber optic grating temperature sensor, a fiber optic grating stress sensor, an optical fiber, an optical fiber connector, and an optical fiber adapter. The fiber optic grating temperature sensor and the fiber optic grating stress sensor are connected by optical fibers and adhered to the outer circumferential surface of the gasket. The optical fiber is wound around the outer circumferential surface of the gasket. The two ends of the optical fiber are connected to the optical fiber adapter through the optical fiber connector. The gasket is fitted on the bolt and located below the nut.

[0004] When a bolt is subjected to external forces (such as tension, compression, or torque), a strain field is generated inside it. The transmission of force causes stress distribution on the surface of the gasket. When the gasket is under stress, the fiber Bragg grating stress sensor deforms accordingly. Axial strain stretches or compresses the sensor, changing the grating period and causing a shift in the reflected wavelength; while transverse strain may indirectly affect the refractive index through the Poisson effect or photoelastic effect of the fiber. When the bolt loosens, the stress in the gasket changes, which is then detected by the fiber Bragg grating stress sensor.

[0005] The effect of temperature on the relevant performance parameters of fiber Bragg grating stress sensors is that changes in the temperature field will cause a thermo-optic effect in the fiber Bragg grating stress sensor. Therefore, fiber Bragg grating temperature sensors are used to compensate for temperature changes, making the fiber Bragg grating stress sensor more accurate.

[0006] Compared with traditional vibration monitoring devices, this invention has the following significant advantages:

[0007] 1. Compared with traditional fiber optic stress sensors that are attached to or embedded in bolts, it does not require disassembly of the original equipment;

[0008] 2. Simple structure, low cost, and easy to use; capable of accurate and reliable measurement and monitoring of bolt stress connection status during fastening and service;

[0009] In summary, the fiber optic grating sensor for wind turbine foundation flange bolts of this invention can effectively meet the urgent needs of modern wind power equipment for real-time monitoring of structural safety, high-reliability operation, and intelligent remote operation and maintenance. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of a fiber Bragg grating sensor structure.

[0011] Figure 2 This is a schematic diagram of a fiber optic adapter and fiber optic connector;

[0012] Figure 3 This is a schematic diagram illustrating the use of this device;

[0013] In the diagram: 1-gasket, 2-fiber Bragg grating temperature sensor, 3-fiber Bragg grating stress sensor, 4-fiber optic cable, 5-fiber optic connector, 6-fiber optic adapter, 7-bolt, 8-nut. Detailed Implementation

[0014] To better understand the structure and function of this utility model, a specific embodiment of a vibration monitoring device for a wind turbine tower is described in detail below with reference to the accompanying drawings. However, it should be understood that these embodiments are merely illustrative of preferred solutions and do not constitute a limitation on the scope of protection of this utility model.

[0015] Example 1: As Figure 1-3 As shown, the fiber optic grating sensor used for wind turbine foundation flange bolts includes a gasket 1, a fiber optic grating temperature sensor 2, a fiber optic grating stress sensor 3, an optical fiber 4, an optical fiber connector 5, and an optical fiber adapter 6. The gasket 1 is circular. The fiber optic grating temperature sensor 2 and the fiber optic grating stress sensor 3 are connected through the optical fiber 4 and are adhered to the outer circumferential surface of the gasket with an adhesive. The optical fiber 4 is wound around the outer circumferential surface of the gasket 1. The 2nd end of the optical fiber 4 is connected to the optical fiber adapter 6 through the optical fiber connector 5.

[0016] In use, the washer 1 is fitted onto the bolt 7 and located below the nut 8. When the bolt loosens, the stress on the washer 1 decreases and acts on the fiber optic grating sensor. When broadband light passes through the fiber optic grating sensor, light of a specific wavelength is reflected back, while the rest passes through the grating. The reflected wavelength is the signal of the bolt loosening. The fiber optic grating temperature sensor is used to compensate for temperature changes, making the fiber optic grating stress sensor more accurate.

Claims

1. A fiber optic grating sensor for wind turbine foundation flange bolts, characterized in that: Includes a gasket (1), a fiber optic temperature sensor (2), a fiber optic stress sensor (3), an optical fiber (4), an optical fiber connector (5), and an optical fiber adapter (6). The fiber optic temperature sensor (2) and the fiber optic stress sensor (3) are connected by the optical fiber (4) and adhered to the outer circumferential surface of the gasket. The optical fiber (4) is wound around the outer circumferential surface of the gasket (1). The two ends of the optical fiber (4) are connected to the optical fiber adapter (6) through the optical fiber connector (5).

2. The fiber optic grating sensor for wind turbine foundation flange bolts according to claim 1, characterized in that: The gasket is a round gasket.

3. The fiber optic grating sensor for wind turbine foundation flange bolts according to claim 1, characterized in that: When in use, the washer (1) is fitted onto the bolt and located below the nut.

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