CN112595253A - Surface strain dynamic optical fiber grating detection device - Google Patents
Surface strain dynamic optical fiber grating detection device Download PDFInfo
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- CN112595253A CN112595253A CN202011247152.3A CN202011247152A CN112595253A CN 112595253 A CN112595253 A CN 112595253A CN 202011247152 A CN202011247152 A CN 202011247152A CN 112595253 A CN112595253 A CN 112595253A
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- 238000001514 detection method Methods 0.000 title claims abstract description 54
- 239000013307 optical fiber Substances 0.000 title claims description 11
- 230000003287 optical effect Effects 0.000 claims abstract description 29
- 239000000835 fiber Substances 0.000 claims abstract description 9
- 238000000034 method Methods 0.000 description 9
- 238000001914 filtration Methods 0.000 description 4
- 230000005540 biological transmission Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 230000007613 environmental effect Effects 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 230000002159 abnormal effect Effects 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 238000003745 diagnosis Methods 0.000 description 2
- 230000036541 health Effects 0.000 description 2
- 238000012544 monitoring process Methods 0.000 description 2
- 230000008859 change Effects 0.000 description 1
- 238000005253 cladding Methods 0.000 description 1
- 239000000306 component Substances 0.000 description 1
- 239000008358 core component Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 230000003628 erosive effect Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 238000010248 power generation Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 230000008054 signal transmission Effects 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 230000007847 structural defect Effects 0.000 description 1
- 238000002604 ultrasonography Methods 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/16—Measuring arrangements characterised by the use of optical techniques for measuring the deformation in a solid, e.g. optical strain gauge
- G01B11/165—Measuring arrangements characterised by the use of optical techniques for measuring the deformation in a solid, e.g. optical strain gauge by means of a grating deformed by the object
Abstract
The invention relates to the technical field of surface strain detection, in particular to a surface strain dynamic fiber grating detection device which comprises a light source, an isolator, a trunk circulator, a filter grating, an optical splitter, surface stress detection units and an upper computer. The invention has reasonable and compact structure and convenient use, and can protect the light source and prevent the light wave from back-emitting to the light source by arranging the isolator which is a one-way channel device; by arranging the filter grating, the broadband light emitted by the light source is filtered and reflected back to the narrow-band light with a specific central wavelength range; through setting up the detection grating, realize taking place deformation, the detection when producing little meeting an emergency to the blade surface, have quick, accurate and sensitive characteristics.
Description
Technical Field
The invention relates to the technical field of surface strain detection, in particular to a surface strain dynamic fiber grating detection device.
Background
The wind driven generator is a large device which integrates the technologies in the fields of traditional machinery, modern electronics and the like and converts wind energy into electric energy. The vigorous development of wind power generation relieves the pressure caused by energy crisis and environmental pollution, and promotes the sustainable development and environmental protection of the earth. As a device for developing and utilizing renewable energy, the related technologies from the structural design to the monitoring of structural health have been paid more and more attention by countries and regions.
Wind power equipment is mostly built at places with abundant wind power resources, such as seasides, fields, mountains and the like, and the abundant wind power resources also correspond to complex and severe natural environments. The blades, as a core component of wind power plants, are manufactured at a cost of about 20% of the total wind power plant, and the size of the blades is being increased to maximize the use of wind energy. Therefore, the blade is often subjected to various bad abnormal loads such as bird strike, flying stones, hail, wind erosion and the like in the service process under the severe working environment, so that damage and faults frequently occur. The related technology aiming at monitoring the health state of the leaf is the research focus of a plurality of scholars and researchers at home and abroad at present.
The traditional blade detection method mainly comprises the step of collecting vibration signals of the blades through a vibration sensor so as to identify and judge the working states of the blades. Abnormal vibration states are identified to predict whether damage has occurred to the structure of the blade.
At present, besides the traditional detection method, a plurality of novel wind turbine blade detection methods exist. Such as ultrasound, image recognition, noise analysis, etc. The above methods are indirect detection methods that reflect structural defects by detecting changes in other environmental parameters caused by deformation. However, the indirect detection method is subject to a plurality of external interference factors, and is not sensitive to the early damage signal characteristics before the blade is defective, so that the detection effect of the method is not ideal. Some sensing methods use sensors that change the configuration of the blade more or less, which also affects the useful life of the blade.
Disclosure of Invention
The invention provides a surface strain dynamic fiber grating detection device, overcomes the defects of the prior art, and can effectively solve the problem that the conventional blade detection method cannot be completed timely and accurately.
The technical scheme of the invention is realized by the following measures: a surface strain dynamic fiber grating detection device comprises a light source, an isolator, a trunk circulator, a filter grating, an optical splitter, surface stress detection units and an upper computer, wherein the light source is connected with the isolator; the surface stress detection unit comprises a branch circulator, a detection grating, a photoelectric converter, a demodulator and an amplifier, wherein the optical splitter is respectively connected with the branch circulator, the branch circulator is respectively connected with the detection grating and the photoelectric converter, the photoelectric converter is connected with the demodulator, the demodulator is connected with the amplifier, and the amplifier is connected with an upper computer.
The following is further optimization or/and improvement of the technical scheme of the invention:
the wind power generator can further comprise a wind power generator, the wind power generator comprises blades, and each blade is provided with at least two detection gratings.
The optical fiber circulator also comprises an optical slip ring, a smooth ring is arranged on a rotating shaft of the blade, and the optical fiber between the branch circulator and the detection grating is wired through the optical slip ring.
The invention has reasonable and compact structure and convenient use, and can protect the light source and prevent the light wave from back-emitting to the light source by arranging the isolator which is a one-way channel device; by arranging the filter grating, the broadband light emitted by the light source is filtered and reflected back to the narrow-band light with a specific central wavelength range; through setting up the detection grating, realize taking place deformation, the detection when producing little meeting an emergency to the blade surface, have quick, accurate and sensitive characteristics.
Drawings
Fig. 1 is a schematic perspective view of a preferred embodiment of the present invention.
Fig. 2 is a block circuit diagram of fig. 1.
The codes in the figures are respectively: 1 is a detection grating, 2 is a blade, 3 is a rotating shaft, and 4 is an optical slip ring.
Detailed Description
The present invention is not limited by the following examples, and specific embodiments may be determined according to the technical solutions and practical situations of the present invention.
In the present invention, for convenience of description, the description of the relative positional relationship of the components is described according to the layout pattern of fig. 1 of the specification, such as: the positional relationship of front, rear, upper, lower, left, right, etc. is determined in accordance with the layout direction of the drawings of the specification.
The invention is further described with reference to the following examples and figures:
as shown in fig. 1 and 2, the surface strain dynamic fiber grating detection device comprises a light source, an isolator, a trunk circulator, a filter grating, an optical splitter, surface stress detection units and an upper computer, wherein the light source is connected with the isolator, the isolator is connected with the trunk circulator, the trunk circulator is respectively connected with the filter grating and the optical splitter, and the optical splitter is respectively connected with at least two surface stress detection units; the surface stress detection unit comprises a branch circulator, a detection grating 1, a photoelectric converter, a demodulator and an amplifier, wherein the optical splitter is respectively connected with the branch circulator, the branch circulator is respectively connected with the detection grating 1 and the photoelectric converter, the photoelectric converter is connected with the demodulator, the demodulator is connected with the amplifier, and the amplifier is connected with an upper computer. In the using process, a plurality of detection gratings 1 are arranged on blades 2 of a wind driven generator, optical signals are emitted from a light source and conducted by optical fibers, and are transmitted to an upper computer through an isolator, a trunk circulator, a filter grating, a trunk circulator, an optical splitter, a branch circulator, the detection gratings 1, the branch circulator, a photoelectric converter, a demodulator and an amplifier in sequence, so that the surface strain of the blades 2 is detected, and corresponding fault prediction and diagnosis are made; the isolator is a one-way channel device, so that the light source can be protected, and light waves are prevented from being reflected back to the light source; by arranging the filter grating, the broadband light emitted by the light source is filtered and reflected back to the narrow-band light with a specific central wavelength range for subsequent detection (the filtering mode is an edge filtering method); by arranging the trunk circulator which is a unidirectional sequential loop device and is provided with three ports, signals are input from the first port and can only be output from the second port, and signals input from the second port and can only be output from the third port, so that optical signals filtered by the filter grating are transmitted to the optical splitter; by arranging the optical splitter, equally dividing the optical signals after equal filtering into multiple paths of branch lights, so that all the branch lights and the optical signals after filtering by the filter grating have the same characteristics of central wavelength and the like; by arranging the detection grating 1, the detection grating has a reflection effect on light with a specific central wavelength, the wavelength of the reflected light changes along with the micro-change of the grating structure, and when a certain position on the surface of the blade 2 deforms and generates micro-strain, the nearby grating structure is immediately influenced, so that the central wavelength of the reflected light is influenced; by arranging the branch circulators which are unidirectional sequential circulation devices, three ports are arranged on the branch circulators, signals are input from the first port and can only be output from the second port, and signals input from the second port and can only be output from the third port, so that optical signals reflected by the detection grating 1 are transmitted to the photoelectric converter; the photoelectric converter, the demodulator, the amplifier and the upper computer are used for converting the optical signal into an electric signal, demodulating and amplifying the electric signal, and transmitting relevant parameter characteristics of the processed electric signal, such as voltage amplitude, time domain, frequency spectrum and the like, into the upper computer in a digital signal form for final analysis. The light source is known in the art and may be an ASE light source, as desired.
The method adopted by the invention is mainly based on the use of Fiber Bragg Gratings (FBGs), compared with various traditional indirect detection methods, the FBG detection method directly detects the strain on the surface of the blade, the blade is tightly adhered to the FBG sensing unit through adhesion, the strain and the same value transmission are realized, and because the reflection wavelength of the FBG is very sensitive to tiny deformation, the FBG sensing unit can also generate corresponding feedback to the early damage signal characteristics of the blade, and the method has the advantages of rapidness, more accuracy and real-time sensitivity; the invention mainly uses the optical signal as the information carrier for transmission, has the characteristics of stable optical signal transmission, strong anti-electromagnetic interference and no influence by external sound and vibration factors, has extremely high signal-to-noise ratio, and can maintain the original characteristics of the measured strain signal to the maximum extent; the FBG sensing unit provided by the invention has a simple structure, the diameter of the optical fiber channel containing the cladding is only about 0.21mm, the diameter of the bare fiber core is less than 0.2mm, the length of the grating area is about 2mm, and the FBG sensing unit is attached to the surface of the blade without any influence on the structural performance of the blade relative to the large-scale size of tens of meters or even tens of meters of the blade, so that the real nondestructive detection is realized; the invention has the characteristics of convenient operation, high automation degree and strong reusability, and can detect the surface strain of the blade and simultaneously realize the detection of other physical quantities such as environmental temperature and the like.
The surface strain dynamic fiber grating detection device can be further optimized or/and improved according to actual needs:
as shown in the attached drawings 1 and 2, the wind driven generator further comprises blades 2, and each blade 2 is provided with at least two detection gratings 1. In use, the arrangement enables the surface strain of the blade 2 to be detected and corresponding fault prediction and diagnosis to be made.
As shown in the attached figures 1 and 2, the optical fiber circulator also comprises an optical slip ring 4, a smooth ring 4 is arranged on a rotating shaft 3 of the blade 2, and the optical fiber between the branch circulator and the detection grating 1 is wired through the optical slip ring 4. In the use process, the smooth ring 4 is a sliding ring mechanism with an optical channel similar to a bearing, the stator part of the smooth ring 4 is provided with a plurality of optical fiber channels, when the smooth ring works, the stator part of the smooth ring 4 is fixed, and the rotor part of the smooth ring 4 and the rotating shaft 3 of the blade 2 do concentric rotation movement with the same rotating speed, so that the problems of optical fiber short circuit, mixed exchange, winding and the like are avoided, and the lossless transmission of optical signals is realized. The smooth ring 4 is known in the art and may operate in a similar manner to an electrical slip ring, as desired.
The above technical features constitute the best embodiment of the present invention, which has strong adaptability and best implementation effect, and unnecessary technical features can be increased or decreased according to actual needs to meet the requirements of different situations.
Claims (3)
1. A surface strain dynamic fiber grating detection device is characterized by comprising a light source, an isolator, a trunk circulator, a filter grating, an optical splitter, surface stress detection units and an upper computer, wherein the light source is connected with the isolator; the surface stress detection unit comprises a branch circulator, a detection grating, a photoelectric converter, a demodulator and an amplifier, wherein the optical splitter is respectively connected with the branch circulator, the branch circulator is respectively connected with the detection grating and the photoelectric converter, the photoelectric converter is connected with the demodulator, the demodulator is connected with the amplifier, and the amplifier is connected with an upper computer.
2. The device according to claim 1, further comprising a wind power generator, wherein the wind power generator comprises blades, and each blade is provided with at least two detection gratings.
3. The surface strain dynamic fiber grating detection device of claim 2, further comprising an optical slip ring, wherein a smooth ring is disposed on the rotating shaft of the blade, and the optical fiber between the branch circulator and the detection grating is wired through the optical slip ring.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202011247152.3A CN112595253A (en) | 2020-11-10 | 2020-11-10 | Surface strain dynamic optical fiber grating detection device |
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| CN202011247152.3A CN112595253A (en) | 2020-11-10 | 2020-11-10 | Surface strain dynamic optical fiber grating detection device |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102519384A (en) * | 2011-12-28 | 2012-06-27 | 烟台睿创微纳技术有限公司 | Device for detecting blade strain on line based on optical fiber grating |
| CN103954227A (en) * | 2014-04-25 | 2014-07-30 | 西南交通大学 | High-sensitivity real-time blade deflection monitoring scheme based on temperature matching |
| CN104215191A (en) * | 2013-05-30 | 2014-12-17 | 成都阜特科技股份有限公司 | Optical fiber grating sensor packaging method |
| CN204359277U (en) * | 2015-01-14 | 2015-05-27 | 华北电力大学（保定） | A kind of turbine blade dynamic strain measurement system |
| CN106471340A (en) * | 2014-04-02 | 2017-03-01 | 克罗马森西有限公司 | For the device from multiple fiber sensor measuring optical signals |
-
2020
- 2020-11-10 CN CN202011247152.3A patent/CN112595253A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102519384A (en) * | 2011-12-28 | 2012-06-27 | 烟台睿创微纳技术有限公司 | Device for detecting blade strain on line based on optical fiber grating |
| CN104215191A (en) * | 2013-05-30 | 2014-12-17 | 成都阜特科技股份有限公司 | Optical fiber grating sensor packaging method |
| CN106471340A (en) * | 2014-04-02 | 2017-03-01 | 克罗马森西有限公司 | For the device from multiple fiber sensor measuring optical signals |
| CN103954227A (en) * | 2014-04-25 | 2014-07-30 | 西南交通大学 | High-sensitivity real-time blade deflection monitoring scheme based on temperature matching |
| CN204359277U (en) * | 2015-01-14 | 2015-05-27 | 华北电力大学（保定） | A kind of turbine blade dynamic strain measurement system |
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