CN104848980A - Bridge stay cable force online detection method and system based on fiber sensing - Google Patents
Bridge stay cable force online detection method and system based on fiber sensing Download PDFInfo
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Abstract
The invention provides a bridge stay cable force online detection method and system based on fiber sensing. The system comprises a fiber grating vibration sensor group, a fiber grating vibration demodulation instrument and a stay cable vibration signal processing unit. The fiber grating vibration sensor group comprises a plurality of fiber grating vibration sensors connected in series with the same fiber, each fiber grating vibration sensor is designed based on a cantilever structure and a double-raster coupling method, and chirp rasters are used to replace Bragg rasters, such that the detection scope of the sensors is enlarged, the stability and the anti-interference capability of the sensors are improved, and at the same time, the manufacturing difficulty of the sensors is reduced. The fiber grating vibration demodulation instrument is based on an edge filtering demodulation principle and employs a wavelength division multiplexing technology to realize distributed measurement of a stay cable force, and multiple fiber grating vibration sensors can be multiplexed in one fiber signal, such that the detection capability of the system is improved, the distributed measurement of the stay cable force is made possible, and a more reliable technical means is provided for online detection of a wide-span bridge stay cable.
Description
Technical field
The invention belongs to optical fiber sensing detection technology field, be specifically related to a kind of bridge cable Suo Li online test method based on Fibre Optical Sensor and system.
Background technology
Drag-line is the important primary structure member of rope class (suspension cable, suspension cable etc.) bridge, and its stress evaluates one of bridge structure safe whether important indicator.Therefore, the Suo Li detection method, particularly online test method of research drag-line, significant to the health status evaluating bridge.
At present, the Suo Li detection method of suspension cable has multiple, as around-France in oil pressure gauge method, magnetic flux method, dynamometry, frequency method etc.But for built bridge, frequency method is almost unique selection.So-called frequency method is exactly carried out the method for its Suo Li of indirect calculation by the natural frequency of vibration transducer measurement drag-line.The feature of frequency method is convenience, flexibly, cost is low, precision is good, can be used for on-line measurement.The key of frequency method is the selection of pick-up unit and the recognition methods of drag-line natural frequency.
The conventional monitoring device based on piezoelectric type vibro-pickup, export weak electric signal, direct transmission range is no more than hundreds of rice, and is afraid of moist, is easily disturbed, can not in long-term work under physical environment, generally only for periodic detection.In addition, cable tension test software supporting with it, can not realize, to the automatic retrieval of inhaul cable vibration characteristic frequency, can not realizing automatic measurement.
In recent years, along with the development of optical fiber sensing technology, the seminar at my place has carried out the research of the bridge cable force on-line monitoring system based on optical fiber grating sensing, achieve some achievements, as 2006 " Wuhan University of Technology's journal " the 28th article " novel fiber grating vibration transducer test stay cable force " of volume the 8th phase.But while these achievements of summary, also find following deficiency:
(1) less stable of Fibre Optical Sensor.Main cause is that the reflectance spectrum of sensing element FBG adopted is narrower, and by the impact of mounting process and variation of ambient temperature, the probability that double grating coupling lost efficacy is large, and the design of assembly structure is also one of reason causing sensor failure in addition.
(2) spot measurement, the multiplexing capacity of system is poor, is difficult to form extensive sensing network, can not realize distributed measurement.
(3) reliability of recognition methods is poor.The method of identification of current employing mainly identifies the first natural frequency of drag-line, and identify that difficulty is very large like this, reliability is very poor.Reason be (as) natural frequency of some long rope is very low, even exceed the low-frequency cutoff scope of sensor, identification will be failed.
For above-mentioned Problems existing, up to the present yet there are no the relevant report of solution.
Summary of the invention
The technical problem to be solved in the present invention is: provide a kind of bridge cable Suo Li online test method based on Fibre Optical Sensor and system, the on-line checkingi for Longspan Bridge drag-line provides more reliable technological means.
The present invention for solving the problems of the technologies described above taked technical scheme is: a kind of bridge cable Suo Li on-line detecting system based on Fibre Optical Sensor, comprise the optical fiber raster vibration sensor group connected successively, optical fiber raster vibration (FBG) demodulator and inhaul cable vibration signal processing unit, it is characterized in that: described optical fiber raster vibration sensor group comprises series connection several optical fiber raster vibration sensors over the same fiber, each optical fiber raster vibration sensor comprises the semi-girder be arranged on bridge cable, the end of semi-girder is connected with mass, the upper and lower surface of semi-girder is arranged with a pair chirp grating, 2 chirp gratings are positioned on an optical fiber, described optical fiber raster vibration (FBG) demodulator comprises wideband light source, coupling mechanism, wavelength division multiplexer and photodetector array, the light of wideband light source enters optical fiber raster vibration sensor group through coupling mechanism, the light signal that optical fiber raster vibration sensor group returns enters wavelength division multiplexer through photo-coupler, and light signal is converted to electric signal by photodetector array and inputs to described inhaul cable vibration signal processing unit again by the output terminal of wavelength division multiplexer,
Described wavelength division multiplexer comprises an input end and n output terminal, export the light that n is positioned at different-waveband, band of light is wider than the maximum bandwidth of optical fiber raster vibration sensor group reflectance spectrum, each output terminal connects a photodetector, the photodetector array described in n photodetector is formed.
By said system, described chirp grating all adopts 2 modes of pasting to be arranged on the upper and lower surface of semi-girder, and Shi Hanzhang, wavelength variable quantity controls within the scope of 1 ± 0.1nm.
By said system, the three dB bandwidth of 2 chirp gratings in same optical fiber raster vibration sensor is 2nm, and the central wavelength difference under original state is less than 0.5nm, and the difference of temperature control coefficient is less than 2pm/ DEG C.
Utilize the online test method that the bridge cable Suo Li on-line detecting system based on Fibre Optical Sensor realizes, it is characterized in that: the vibratory response being obtained drag-line by the optical fiber raster vibration sensor group that bridge cable is installed, analyze the rumble spectrum of drag-line, identify the fundamental vibration frequency of drag-line, calculate the Suo Li of drag-line according to the relation of Suo Li and fundamental frequency.
As stated above, identify that the method for the fundamental vibration frequency of drag-line is: the fundamental vibration frequency asking for drag-line according to the frequency statistics value of two rank adjacent spectral peaks any in drag-line frequency spectrum.
Beneficial effect of the present invention is: adopt chirp grating to replace Bragg grating, expand the sensing range of sensor, improve stability and the antijamming capability of sensor, reduce the manufacture difficulty of sensor simultaneously; Optical fiber raster vibration (FBG) demodulator designs based on edge filter demodulation demodulation principle, and adopt wavelength-division multiplex technique to realize the distributed measurement of Cable power, making in a road fiber-optic signal can multiplexing multiple optical fiber raster vibration sensor, not only increase the detectability of system, also make the distributed measurement of Cable power become possibility, the on-line checkingi for Longspan Bridge drag-line provides more reliable technological means; Adopt filter method, reduce frequency identification interval, improve the accuracy identified; Adopt the frequency statistics value at spectrum peak, arbitrary neighborhood two rank to obtain the fundamental frequency of inhaul cable vibration, reduce the identification difficulty of guy cable vibrating base frequency.
Accompanying drawing explanation
Fig. 1 is the system architecture schematic diagram of one embodiment of the invention.
Fig. 2 is the structural representation of fiber-optic grating sensor.
Fig. 3 is optical fiber raster vibration sensor fundamental diagram.
Fig. 4 is the structural representation of optical fiber raster vibration (FBG) demodulator.
In figure: 1-optical fiber, 2-first chirp grating, 3-second chirp grating, 4-mass, 5-semi-girder.
Embodiment
Below in conjunction with instantiation and accompanying drawing, the present invention will be further described.
A kind of bridge cable Suo Li on-line detecting system based on Fibre Optical Sensor, as shown in Figure 1, comprise the optical fiber raster vibration sensor group, optical fiber raster vibration (FBG) demodulator and the inhaul cable vibration signal processing unit that connect successively, preferably can also increase the alarm unit be connected with inhaul cable vibration signal processing unit, analyze and judge drag-line state whether safety.Described optical fiber raster vibration sensor group comprises series connection several optical fiber raster vibration sensors over the same fiber, each optical fiber raster vibration sensor as shown in Figure 2, comprise the semi-girder 5 (single cantilever beam structure) be arranged on bridge cable, the end of semi-girder 5 is connected with mass 4, the upper and lower surface of semi-girder 5 is arranged with a pair chirp grating, be respectively the first chirp grating 2 and the second chirp grating 3,2 chirp gratings are positioned on an optical fiber 1.Described optical fiber raster vibration (FBG) demodulator as shown in Figure 4, comprise wideband light source, coupling mechanism, wavelength division multiplexer and photodetector array, the light of wideband light source enters optical fiber raster vibration sensor group through coupling mechanism, the light signal that optical fiber raster vibration sensor group returns enters wavelength division multiplexer through photo-coupler, and light signal is converted to electric signal by photodetector array and inputs to described inhaul cable vibration signal processing unit again by the output terminal of wavelength division multiplexer; Described wavelength division multiplexer comprises an input end and n output terminal, export the light that n is positioned at different-waveband, band of light is wider than the maximum bandwidth of optical fiber raster vibration sensor group reflectance spectrum, each output terminal connects a photodetector, the photodetector array described in n photodetector is formed.
Described chirp grating all adopts 2 modes of pasting (namely only pasting the two ends of grating) to be arranged on the upper and lower surface of semi-girder, and Shi Hanzhang when pasting, wavelength variable quantity controls within the scope of 1 ± 0.1nm.
The three dB bandwidth of 2 chirp gratings in same optical fiber raster vibration sensor is 2nm, and the central wavelength difference under original state is less than 0.5nm, and the difference of temperature control coefficient is less than 2pm/ DEG C.
The principle of work of optical fiber raster vibration sensor, as shown in Figure 3.When fiber grating is in original state (state when not vibrating), the state of the reflectance spectrum of double grating is as shown in the picture left above, and the output signal that now sensor is corresponding, as shown in the figure of lower-left, is a horizontal linear.After sensor does sinusoidal vibration, under the inertia effect of mass, semi-girder deforms, produce periodic strain, thus the reflectance spectrum of double grating also generating period move, as shown in top right plot, the output signal that now sensor is corresponding, as shown in bottom-right graph, is a sinusoidal waveform.The output signal of sensor has reproduced the vibrational state of sensor.
As Fig. 4, in optical fiber raster vibration (FBG) demodulator, add 1 × 8 type wavelength division multiplexer, its effect is that the optical fiber raster vibration sensor of 8 different-wavebands is multiplexed into a passage road optical fiber entering into (FBG) demodulator, after wavelength division multiplexer, the reflected signal of 8 sensors is separated, from 8 different port injections, then converts corresponding electric signal to through photodetector.
Wave band shared by above-mentioned optical fiber raster vibration sensor and the interval between sensor wave band are all corresponding with the index of correlation of wavelength division multiplexer.
Utilize the online test method that the above-mentioned bridge cable Suo Li on-line detecting system based on Fibre Optical Sensor realizes, the vibratory response of drag-line is obtained by the optical fiber raster vibration sensor group that bridge cable is installed, analyze the rumble spectrum of drag-line, identify the fundamental vibration frequency of drag-line, calculate the Suo Li of drag-line according to the relation of Suo Li and fundamental frequency.
Identify that the method for the fundamental vibration frequency of drag-line is specially: the fundamental vibration frequency asking for drag-line according to the frequency statistics value of two rank adjacent spectral peaks any in drag-line frequency spectrum.
The method mainly comprises following three steps: (1) obtains the rumble spectrum of drag-line: in the present embodiment, system acquisition set of frequency is 20Hz, carries out a fft analysis to the time course data of every 10 seconds, obtains the rumble spectrum of drag-line; (2) drag-line fundamental frequency signal identification: according to the design rope force value of drag-line, the base frequency range of estimation drag-line, then bandpass filtering is carried out to inhaul cable vibration frequency spectrum, reduce frequency identification interval, the frequency that each rank peak value is corresponding is read, if there are any three rank side frequencies to meet formula f from filtered signal
i+1-f
i=f
i-f
i-1=f
0, then difference f
0for the fundamental vibration frequency of drag-line; (3) Suo Li of drag-line calculates: according to formula T=4ml
2f
0 2, calculate the Suo Li T of drag-line, in formula, m is the line density of drag-line, and l is the effective length of drag-line.
Evaluating the link of drag-line state, not with the Suo Lizuo in drag-line a certain moment for evaluation index, and using the Cable power variation tendency in one period of division of day and night as Appreciation gist.
Above embodiment is only for illustration of design philosophy of the present invention and feature, and its object is to enable those skilled in the art understand content of the present invention and implement according to this, protection scope of the present invention is not limited to above-described embodiment.So all equivalent variations of doing according to disclosed principle, mentality of designing or modification, all within protection scope of the present invention.
Claims (5)
1. the bridge cable Suo Li on-line detecting system based on Fibre Optical Sensor, comprise the optical fiber raster vibration sensor group connected successively, optical fiber raster vibration (FBG) demodulator and inhaul cable vibration signal processing unit, it is characterized in that: described optical fiber raster vibration sensor group comprises series connection several optical fiber raster vibration sensors over the same fiber, each optical fiber raster vibration sensor comprises the semi-girder be arranged on bridge cable, the end of semi-girder is connected with mass, the upper and lower surface of semi-girder is arranged with a pair chirp grating, 2 chirp gratings are positioned on an optical fiber, described optical fiber raster vibration (FBG) demodulator comprises wideband light source, coupling mechanism, wavelength division multiplexer and photodetector array, the light of wideband light source enters optical fiber raster vibration sensor group through coupling mechanism, the light signal that optical fiber raster vibration sensor group returns enters wavelength division multiplexer through photo-coupler, and light signal is converted to electric signal by photodetector array and inputs to described inhaul cable vibration signal processing unit again by the output terminal of wavelength division multiplexer,
Described wavelength division multiplexer comprises an input end and n output terminal, export the light that n is positioned at different-waveband, band of light is wider than the maximum bandwidth of optical fiber raster vibration sensor group reflectance spectrum, each output terminal connects a photodetector, the photodetector array described in n photodetector is formed.
2. the bridge cable Suo Li on-line detecting system based on Fibre Optical Sensor according to claim 1, it is characterized in that: described chirp grating all adopts 2 modes of pasting to be arranged on the upper and lower surface of semi-girder, and Shi Hanzhang, wavelength variable quantity controls within the scope of 1 ± 0.1nm.
3. the bridge cable Suo Li on-line detecting system based on Fibre Optical Sensor according to claim 1, it is characterized in that: the three dB bandwidth of 2 chirp gratings in same optical fiber raster vibration sensor is 2nm, central wavelength difference under original state is less than 0.5nm, and the difference of temperature control coefficient is less than 2pm/ ° of C.
4. utilize the online test method that the bridge cable Suo Li on-line detecting system based on Fibre Optical Sensor described in claim 1 realizes, it is characterized in that: the vibratory response being obtained drag-line by the optical fiber raster vibration sensor group that bridge cable is installed, analyze the rumble spectrum of drag-line, identify the fundamental vibration frequency of drag-line, calculate the Suo Li of drag-line according to the relation of Suo Li and fundamental frequency.
5. online test method according to claim 4, is characterized in that: identify that the method for the fundamental vibration frequency of drag-line is: the fundamental vibration frequency asking for drag-line according to the frequency statistics value of two rank adjacent spectral peaks any in drag-line frequency spectrum.
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Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105954791A (en) * | 2016-06-01 | 2016-09-21 | 长江大学 | Vibration ground wave fiber sensing detection system for prevention of burglary and excavation of underground historical relics |
| CN108318158A (en) * | 2017-01-18 | 2018-07-24 | 上银科技股份有限公司 | The method for detecting the linear slide rail precompressed value variation of toolroom machine |
| CN108563111A (en) * | 2018-03-28 | 2018-09-21 | 大连理工大学 | Wireless distributed control system and method are vibrated for three layers of chain structure |
| CN108613763A (en) * | 2018-05-11 | 2018-10-02 | 上海市建筑科学研究院 | Fiber Bragg grating type drag-line cable force monitoring sensor based on frequency method and method for sensing |
| CN109334715A (en) * | 2018-10-24 | 2019-02-15 | 西南交通大学 | A kind of optical fiber orbit occupancy monitoring system and method based on vibration measurement |
| CN109827697A (en) * | 2019-03-19 | 2019-05-31 | 东南大学 | Suspension cable time-varying Suo Li recognition methods based on local mean value mode decomposition |
| CN111238710A (en) * | 2020-01-13 | 2020-06-05 | 武汉理工大学 | Bridge cable force state monitoring device and monitoring method based on weak grating array |
| CN111735532A (en) * | 2020-06-24 | 2020-10-02 | 淮阴工学院 | Bridge resonance testing device and method |
| CN113624267A (en) * | 2021-07-21 | 2021-11-09 | 浙江理工大学 | Fiber grating center wavelength demodulation system and demodulation instrument based on edge filtering |
| CN113720435A (en) * | 2021-09-09 | 2021-11-30 | 长沙深之瞳信息科技有限公司 | Indoor text security fiber sensing system and monitoring method |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6212306B1 (en) * | 1999-10-07 | 2001-04-03 | David J. F. Cooper | Method and device for time domain demultiplexing of serial fiber Bragg grating sensor arrays |
| CN202403851U (en) * | 2011-12-28 | 2012-08-29 | 昆明理工大学 | Fiber Bragg grating load cell of anchor cable frame composite structure |
| CN104215321A (en) * | 2014-09-22 | 2014-12-17 | 西安工程大学 | Circuit breaker vibration monitor system and method based on optical fiber sensors |
| CN104848927A (en) * | 2015-05-21 | 2015-08-19 | 武汉理工大学 | Vibration detection system based on chirped grating sensing and wavelength division multiplexing technology |
-
2015
- 2015-06-08 CN CN201510308842.8A patent/CN104848980B/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6212306B1 (en) * | 1999-10-07 | 2001-04-03 | David J. F. Cooper | Method and device for time domain demultiplexing of serial fiber Bragg grating sensor arrays |
| CN202403851U (en) * | 2011-12-28 | 2012-08-29 | 昆明理工大学 | Fiber Bragg grating load cell of anchor cable frame composite structure |
| CN104215321A (en) * | 2014-09-22 | 2014-12-17 | 西安工程大学 | Circuit breaker vibration monitor system and method based on optical fiber sensors |
| CN104848927A (en) * | 2015-05-21 | 2015-08-19 | 武汉理工大学 | Vibration detection system based on chirped grating sensing and wavelength division multiplexing technology |
Non-Patent Citations (3)
| Title |
|---|
| 刘胜春等: "基于光纤光栅传感测试技术的桥梁健康监测系统", 《工程论坛》 * |
| 刘胜春等: "新型光纤光栅振动传感器测试斜拉索索力", 《武汉理工大学学报》 * |
| 南秋明等: "啁啾光纤光栅的传感性能及测量方法研究", 《功能材料》 * |
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105954791A (en) * | 2016-06-01 | 2016-09-21 | 长江大学 | Vibration ground wave fiber sensing detection system for prevention of burglary and excavation of underground historical relics |
| CN108318158A (en) * | 2017-01-18 | 2018-07-24 | 上银科技股份有限公司 | The method for detecting the linear slide rail precompressed value variation of toolroom machine |
| CN108563111A (en) * | 2018-03-28 | 2018-09-21 | 大连理工大学 | Wireless distributed control system and method are vibrated for three layers of chain structure |
| CN108613763A (en) * | 2018-05-11 | 2018-10-02 | 上海市建筑科学研究院 | Fiber Bragg grating type drag-line cable force monitoring sensor based on frequency method and method for sensing |
| CN108613763B (en) * | 2018-05-11 | 2023-11-03 | 上海市建筑科学研究院 | Fiber bragg grating type inhaul cable force monitoring sensor and sensing method based on frequency method |
| CN109334715A (en) * | 2018-10-24 | 2019-02-15 | 西南交通大学 | A kind of optical fiber orbit occupancy monitoring system and method based on vibration measurement |
| CN109827697A (en) * | 2019-03-19 | 2019-05-31 | 东南大学 | Suspension cable time-varying Suo Li recognition methods based on local mean value mode decomposition |
| CN111238710A (en) * | 2020-01-13 | 2020-06-05 | 武汉理工大学 | Bridge cable force state monitoring device and monitoring method based on weak grating array |
| CN111735532A (en) * | 2020-06-24 | 2020-10-02 | 淮阴工学院 | Bridge resonance testing device and method |
| CN113624267A (en) * | 2021-07-21 | 2021-11-09 | 浙江理工大学 | Fiber grating center wavelength demodulation system and demodulation instrument based on edge filtering |
| CN113624267B (en) * | 2021-07-21 | 2024-05-03 | 浙江理工大学 | Fiber bragg grating center wavelength demodulation system and demodulator based on edge filtering |
| CN113720435A (en) * | 2021-09-09 | 2021-11-30 | 长沙深之瞳信息科技有限公司 | Indoor text security fiber sensing system and monitoring method |
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