CN102680263B - Combined parameter monitoring system - Google Patents
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- CN102680263B CN102680263B CN201210156240.1A CN201210156240A CN102680263B CN 102680263 B CN102680263 B CN 102680263B CN 201210156240 A CN201210156240 A CN 201210156240A CN 102680263 B CN102680263 B CN 102680263B
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Abstract
The invention discloses a combined parameter monitoring system, and relates to the technical field of nondestructive examination. A light beam emitted by a tunable light source is transmitted to a combined parameter sensing unit through an optical fiber isolator; a characteristic bragg wavelength in the combined parameter sensing unit is modulated according to change of external temperature and strain; the light intensity of incident light is modulated according to the condition of a sound emission signal at a measured position, so that a modulated light signal can be acquired; the combined parameter modulation unit demodulates the modulated characteristic bragg wavelength and acquires an external temperature condition and an external strain condition; the modulated light signal is demodulated, so that the intensity and the frequency of the sound emission signal can be obtained; and an upper machine can be used for analyzing the external temperature condition, the external strain condition and the intensity and the frequency of the sound emission signal so as to acquire a structure completeness condition of a monitored object. The system is favorable for distributed detection; according to a verification experiment, the electromagnetic interference resistance is high, and the remote distance transmission is realized; and the system is suitable for being used for monitoring an embedded structure and evaluating the completeness.
Description
Technical field
The present invention relates to technical field of nondestructive testing, relate to the aspect such as Fibre Optical Sensor and acoustic emission detection, particularly relate to a kind of complex parameter monitoring system.
Background technology
In order to prevent the generation of disaster, all parts used all need carry out inspection and suitably safeguard, especially the key structure place of critical component or parts, such as: the perishable places such as the crucial forced position such as the crane span structure rocker bearing of large bridge and crude oil storage tank tank bottom, by checking its integrality and structural health, guarantee the normal operation of measurand.How to carry out monitoring structural health conditions better own through becoming a current important research direction.There is multiple method at present for people's selective recognition structural damage and defect, except traditional visual examination, the development comprising the non-destructive Detection Techniques of multiple lossless detection technology is subject to people's attention day by day, such as: ultrasonic scanning, Magnetic Flux Leakage Inspecting, eddy-current technique, radiological survey X and conventional piezoelectric formula acoustic emission detection technology.In this several nondestructiving detecting means mentioned, except acoustic emission detection method, all the other technology all belong to off-line checking method, all require that checked object is out of service when Detection task carries out, and sense cycle is long and cost is higher.Acoustic emission testing technology evaluates material property or structural intergrity by the stress wave acoustic emission signal accepting to produce because of the quick release of the strain such as crack propagation and plastic yield in material structure, this technology is as a kind of on-line checkingi means, be the new development of sensor measuring technology, have larger application advantage relative to all the other several offline inspection technology.But acoustic emission testing technology also has weak point, such as: calibrate AE sensor is based on piezoelectric effect, its principle of work is the transmission of electric charge, this causes calibrate AE sensor antijamming capability under electromagnetic environment not strong, be difficult to obtain practical application under strong electromagnetic environment, in addition, in large scale structure monitoring and integrity assessment, longer signal cable often causes the decay of signal and introduces noise, adopt coaxial shielded cable can reduce the introducing of noise, but the recovery operation that lays reaching hundreds of meters of cables is also a larger burden to Site Detection personnel.
Optical fiber sensing technology take light wave as carrier, optical fiber is medium, perception also transmits extraneous measured signal, it is the New Sensing Technology developed rapidly along with the development of Fibre Optical Communication Technology, there is the unique advantage that other carriers a series of and medium are difficult to compare, such as: small and light, electromagnetism interference and radiation resistance are good, be particularly suitable for using under the rugged surroundings such as strong electromagnetic, inflammable, explosive and narrow space, optical fiber is a kind of excellent low loss line simultaneously, is applicable to remote recording and the transmission of signal.
1) Chinese patent CN1818625A, publication date on August 16th, 2006, disclosed a kind of fiber grating acoustic emission and temperature sensor, describe a kind of application idea of the novel sensor based on fiber grating.
2) Chinese patent CN102313779A, publication date on January 11st, 2012, disclosed a kind of acoustic emission signal sensor-based system based on Fiber Bragg Grating FBG proposes the building of sensor-based system based on this thinking in more detail.
3) Chinese patent CN101813238A, a kind of Sagnac/Mach-Zehnder interferometer Distributed optical fiber sensor system and time domain positioning method thereof disclosed in 25 days Augusts in 2010 of publication date.
Inventor is realizing in process of the present invention, finds at least there is following shortcoming and defect in prior art:
1st) and 2) two fiber-optic grating sensors described by patent all require that demodulating system has higher frequency, demodulation frequency, but found by relevant practice, current technical merit is difficult to ensure that the grating sensor required hundreds of kHz that normally work even go up the frequency, demodulation frequency of million Hz, although this fiber-optic grating sensor possible in theory is difficult to realization.
3rd) patent only can realize the sensing to disturbance, and cannot by realizing the integrity analysis to measurand to the composite measurement of the external parameter such as temperature, strain.
Summary of the invention
The invention provides a kind of complex parameter monitoring system, the present invention is by realizing the integrity analysis to measurand to the composite measurement of the external parameter such as temperature, strain, described below:
A kind of complex parameter monitoring system, described complex parameter monitoring system comprises: tunable optical source, fibre optic isolater, complex parameter sensing unit, complex parameter demodulating unit and host computer,
The light beam that described tunable optical source sends transfers to described complex parameter sensing unit through described fibre optic isolater, is modulated the feature bragg wavelength in described complex parameter sensing unit by the change of ambient temperature and strain; The light intensity of acoustic emission signal situation to incident light according to measured place is modulated, and obtains the rear light signal of modulation; Described complex parameter demodulating unit carries out demodulation by the feature bragg wavelength after modulation, obtains ambient temperature situation and strain conditions; Demodulation is carried out to light signal after described modulation, obtains power and the frequency of acoustic emission signal; By described host computer, the power of described ambient temperature situation, described strain conditions, described acoustic emission signal and frequency are analyzed, obtain testee structural intergrity situation.
Fiber connection is passed through between described complex parameter sensing unit and described complex parameter demodulating unit.
Described optical fiber is specially: SMF-28 type single-mode fiber.
When the described complex parameter demodulating unit in described complex parameter monitoring system is reflection-type demodulating unit, described complex parameter monitoring system comprises: described tunable optical source, described fibre optic isolater, described host computer,
Wherein, described complex parameter sensing unit comprises: optical fiber circulator, Bragg grating sensing unit and Mach-Zehnder interfere type voice sending sensor unit, and described complex parameter demodulating unit comprises: reflection-type Bragg grating wavelength demodulating unit and Mach-Zehnder acoustic emission light intensity demodulating unit;
The light beam that described tunable optical source sends is through described fibre optic isolater, described Bragg grating sensing unit is arrived according to the port order of described optical fiber circulator, the feature bragg wavelength of described Bragg grating sensing unit conducts to described reflection-type Bragg grating wavelength demodulating unit by described optical fiber circulator, obtains described ambient temperature situation and described strain conditions by the change of feature bragg wavelength described in demodulation; Described ambient temperature situation and described strain conditions are transferred to described host computer by described reflection-type Bragg grating wavelength demodulating unit; All the other spectrum through described Bragg grating sensing unit provide incident light for described Mach-Zehnder interfere type voice sending sensor unit, acoustic emission signal modulates described incident light, change the light intensity of described incident light, described Mach-Zehnder acoustic emission light intensity demodulating unit obtains light intensity signal, described light intensity signal is converted to electric signal, and by described electric signal transmission to host computer; Described host computer is analyzed the power of described ambient temperature situation, described strain conditions, described acoustic emission signal and frequency, obtains described testee structural intergrity situation.
Described optical fiber circulator is specially: insertion loss≤0.7dB, return loss >=60dB.
When the described complex parameter demodulating unit in described complex parameter monitoring system is transmission-type demodulating unit, described complex parameter monitoring system comprises: described tunable optical source, described fibre optic isolater, described host computer,
Wherein, described complex parameter sensing unit comprises: Bragg grating sensing unit and Mach-Zehnder interfere type voice sending sensor unit, and described complex parameter demodulating unit comprises: transmission-type Bragg grating wavelength demodulating unit and Mach-Zehnder acoustic emission light intensity demodulating unit;
The light beam that described tunable optical source sends directly arrives described Bragg grating sensing unit after described fibre optic isolater, the feature bragg wavelength of described Bragg grating sensing unit to described transmission-type Bragg grating wavelength demodulating unit, obtains described ambient temperature situation and described strain conditions by feature bragg wavelength described in demodulation by described Mach-Zehnder interfere type voice sending sensor cell conducts; Described ambient temperature situation and described strain conditions are transferred to described host computer by described transmission-type Bragg grating wavelength demodulating unit; All the other spectrum through described Bragg grating sensing unit provide incident light for described Mach-Zehnder interfere type voice sending sensor unit, change the light intensity of described incident light, described Mach-Zehnder acoustic emission light intensity demodulating unit obtains light intensity signal, described light intensity signal is converted to electric signal, and by described electric signal transmission to described host computer; Described host computer is analyzed the power of described ambient temperature situation, described strain conditions, described acoustic emission signal and frequency, obtains described testee structural intergrity situation.
When the described complex parameter demodulating unit in described complex parameter monitoring system is transmission-type demodulating unit, described complex parameter monitoring system comprises: described tunable optical source, described fibre optic isolater, described host computer,
Wherein, described complex parameter sensing unit comprises: Bragg grating sensing unit, Mach-Zehnder interfere type voice sending sensor unit and coupling mechanism, and described complex parameter demodulating unit comprises: transmission-type Bragg grating wavelength demodulating unit and Mach-Zehnder acoustic emission light intensity demodulating unit;
The light beam that described tunable optical source sends directly is divided into first via light beam and the second road light beam after described fibre optic isolater and described coupling mechanism; Described first via light beam arrives described Bragg grating sensing unit, the feature bragg wavelength of described Bragg grating sensing unit conducts to described transmission-type Bragg grating wavelength demodulating unit, obtains described ambient temperature situation and described strain conditions by the change of demodulation feature bragg wavelength; Described ambient temperature situation and described strain conditions are transferred to described host computer by described transmission-type Bragg grating wavelength demodulating unit; Described second road light beam provides incident light for described Mach-Zehnder interfere type voice sending sensor unit, change the light intensity of described incident light, described Mach-Zehnder acoustic emission light intensity demodulating unit obtains light intensity signal, described light intensity signal is converted to electric signal, and by described electric signal transmission to described host computer; Described host computer is analyzed the power of described ambient temperature situation, described strain conditions, described acoustic emission signal and frequency, obtains described testee structural intergrity situation.
When the described complex parameter demodulating unit in described complex parameter monitoring system is transmission-type demodulating unit, described complex parameter monitoring system comprises: described tunable optical source, described fibre optic isolater, described host computer,
Wherein, described complex parameter sensing unit comprises: Bragg grating sensing unit, Mach-Zehnder interfere type voice sending sensor unit and coupling mechanism, and described complex parameter demodulating unit comprises: transmission-type Bragg grating wavelength demodulating unit and Mach-Zehnder acoustic emission light intensity demodulating unit;
The light beam that described tunable optical source sends is divided into the 3rd road light beam and the 4th road light beam after described fibre optic isolater, described Bragg grating sensing unit and described coupling mechanism, feature bragg wavelength in described 3rd road light beam to described transmission-type Bragg grating wavelength demodulating unit, obtains ambient temperature situation and strain conditions by the change of demodulation feature bragg wavelength by described coupler transfer; Described ambient temperature situation and described strain conditions are transferred to described host computer by described transmission-type Bragg grating wavelength demodulating unit; Described 4th road light beam provides incident light for described Mach-Zehnder interfere type voice sending sensor unit, change the light intensity of described incident light, described Mach-Zehnder acoustic emission light intensity demodulating unit obtains light intensity signal, described light intensity signal is converted to electric signal, and by described electric signal transmission to described host computer; Described host computer is analyzed the power of described ambient temperature situation, described strain conditions, described acoustic emission signal and frequency, obtains described testee structural intergrity situation.
Described Mach-Zehnder acoustic emission light intensity demodulating unit specifically comprises: photodetector and data collecting card,
Described photodetector obtains described light intensity signal, and described light intensity signal is converted to described electric signal, and by described data collecting card by described electric signal transmission extremely described host computer.
Described coupling mechanism is specially: 1 × 2 type coupling mechanism.
The beneficial effect of technical scheme provided by the invention is:
The invention provides a kind of complex parameter monitoring system, the acoustic emission signal of the coupling unit after this system adopts Mach-Zehnder interfere type voice sending sensor unit inspection and testee to fit, is suitable for damascene structures monitoring and integrity assessment; This Mach-Zehnder interfere type voice sending sensor unit be connected in series with optical fiber Bragg grating sensor or and connect, be easy to realize Distributed Detection; Verify by experiment, the anti-electromagnetic interference capability of native system is strong, achieves long-distance transmissions.
Accompanying drawing explanation
Fig. 1 is the structural representation of a kind of complex parameter monitoring system provided by the invention;
The structural representation that Fig. 2 is the complex parameter demodulating unit in a kind of complex parameter monitoring system provided by the invention when being reflection-type demodulating unit;
The structural representation that Fig. 3 is the complex parameter demodulating unit of a kind of complex parameter monitoring system provided by the invention when being transmission-type demodulating unit;
Another structural representation that Fig. 4 is the complex parameter demodulating unit of a kind of complex parameter monitoring system provided by the invention when being transmission-type demodulating unit;
Another structural representation that Fig. 5 is the complex parameter demodulating unit of a kind of complex parameter monitoring system provided by the invention when being transmission-type demodulating unit;
Fig. 6 is the annexation schematic diagram between Mach-Zehnder acoustic emission light intensity demodulating unit provided by the invention and host computer;
Fig. 7 is typical burst acoustic emission signal oscillogram provided by the invention;
Fig. 8 is surveyed acoustic emission waveform figure by strong electromagnetic interference environment provided by the invention presses down electric-type calibrate AE sensor;
Fig. 9 is surveyed acoustic emission waveform figure by the moral interfere type voice sending sensor unit of Mach under strong electromagnetic interference environment provided by the invention-once.In accompanying drawing, the list of parts representated by each label is as follows:
1: tunable optical source; 2: fibre optic isolater;
3: complex parameter sensing unit; 4: complex parameter demodulating unit;
5: host computer; 31: optical fiber circulator;
32: Bragg grating sensing unit; 34: coupling mechanism
41: reflection-type Bragg grating wavelength demodulating unit; 421: photodetector;
42: Mach-Zehnder acoustic emission light intensity demodulating unit; 422: data collecting card;
43: transmission-type Bragg grating wavelength demodulating unit;
33: Mach-Zehnder interfere type voice sending sensor unit.
Embodiment
For making the object, technical solutions and advantages of the present invention clearly, below in conjunction with accompanying drawing, embodiment of the present invention is described further in detail.
In order to realize the integrity assessment to measurand, embodiments provide a kind of complex parameter monitoring system, see Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5 and Fig. 6, described below:
A kind of complex parameter monitoring system that the embodiment of the present invention provides designs based on Fibre Optical Sensor principle, when the key position of key structure or parts is subject to certain stress, a large amount of acoustic emission signals and certain strain will inevitably be produced, native system monitors temperature, the parameter such as strain and acoustic emission signal at measured place simultaneously, assessed by the duty comprehensively analyzing parameters current to key position, native system is the combination of conventional piezoelectric formula acoustic emission and optical fiber sensing technology, measures while can realizing multiple important parameter.
A kind of complex parameter monitoring system, see Fig. 1, comprising: tunable optical source 1, fibre optic isolater 2, complex parameter sensing unit 3, complex parameter demodulating unit 4 and host computer 5,
The light beam that tunable optical source 1 sends transfers to complex parameter sensing unit 3 through fibre optic isolater 2, is modulated the feature bragg wavelength in complex parameter sensing unit 3 by the change of ambient temperature and strain; The light intensity of acoustic emission signal situation to incident light according to measured place is modulated, and obtains the rear light signal of modulation; Complex parameter demodulating unit 4 carries out demodulation by the feature bragg wavelength after modulation, obtains ambient temperature situation and strain conditions; Demodulation is carried out to light signal after modulation, obtains power and the frequency of acoustic emission signal; By host computer 5 to external world the power of temperature regime, strain conditions, acoustic emission signal and frequency analyze, obtain testee structural intergrity situation.
Wherein, the change of ambient temperature and strain specifically comprises: the rising of ambient temperature or reduction; Strain is tensile strain or compressive strain.
Wherein, the host computer 5 to external world power of temperature regime, strain conditions, acoustic emission signal and frequency is analyzed, obtain testee structural intergrity situation specifically to comprise: preset reasonable temperature parameter, with strain relevant feature bragg wavelength, the amplitude of acoustic emission signal and frequency parameter, host computer 5 to external world temperature regime and reasonable temperature parameter is analyzed; Strain conditions and the feature bragg wavelength relevant with strain are analyzed; The power of acoustic emission signal and the amplitude of acoustic emission signal are analyzed; The frequency of acoustic emission signal and frequency parameter are analyzed, obtains testee structural intergrity situation.
Wherein, measured place is specially: complex parameter sensing unit 3 is by the coupling unit of construction adhesive and testee.
Wherein, construction adhesive is generally: thermosetting epoxy resin, such as: butylphenol, acrylic acid gather phthalimide, fourth eyeball phenolics or fragrant adoption phthalein amine and is pasted onto in testee structure, there is good coupling effect between such complex parameter sensing unit 3 and acoustic emission signal, good acoustic emission signal sensing effect can be realized.
Wherein, eliminated the spectrum being reflected back tunable optical source 1 by fibre optic isolater 2, improve the stability of light source output spectrum.
Further, in order to meet the needs of remote recording, between complex parameter sensing unit 3 and complex parameter demodulating unit 4, Fiber connection is passed through.Wherein, the length of optical fiber sets according to the needs in practical application, and during specific implementation, the embodiment of the present invention does not limit this.
According to the difference of on-the-spot light path condition and Bragg grating wavelength demodulating unit 4, the embodiment of the present invention proposes the complex parameter monitoring system of several different structure, specifically can select according to different optical fiber structures and condition the embodiment scheme that is applicable to when implementing.
Further, in order to ensure the reliability of Signal transmissions, for the wavelength of optical signal scope of native system, optical fiber in the embodiment of the present invention is preferably: SMF-28 type single-mode fiber, this type optical fiber has low dispersion, highly reliable, the feature such as low-loss and high power capacity, can meet the requirement of native system preferably.
Embodiment 1
When the complex parameter demodulating unit 4 in complex parameter monitoring system is reflection-type demodulating unit, see Fig. 2, this complex parameter monitoring system comprises: tunable optical source 1, fibre optic isolater 2, host computer 5, wherein, complex parameter sensing unit 3 comprises: optical fiber circulator 31, Bragg grating sensing unit 32 and Mach-Zehnder interfere type voice sending sensor unit 33, and complex parameter demodulating unit 4 comprises: reflection-type Bragg grating wavelength demodulating unit 41 and Mach-Zehnder acoustic emission light intensity demodulating unit 42;
The light beam that tunable optical source 1 sends is through fibre optic isolater 2, Bragg grating sensing unit 32 is arrived according to the port order of optical fiber circulator 31, the feature bragg wavelength of Bragg grating sensing unit 32 conducts to reflection-type Bragg grating wavelength demodulating unit 41 by optical fiber circulator 31, obtains ambient temperature situation and strain conditions by the change of demodulation feature bragg wavelength; Ambient temperature situation and strain conditions are transferred to host computer 5 by reflection-type Bragg grating wavelength demodulating unit 41; All the other spectrum through Bragg grating sensing unit 32 provide incident light for Mach-Zehnder interfere type voice sending sensor unit 33, acoustic emission signal modulating the incident light, change the light intensity of incident light, Mach-Zehnder acoustic emission light intensity demodulating unit 42 obtains light intensity signal, light intensity signal is converted to electric signal, and by electric signal transmission to host computer 5; The host computer 5 to external world power of temperature regime, strain conditions, acoustic emission signal and frequency is analyzed, and obtains testee structural intergrity situation.
Wherein, optical fiber circulator 31 is non-reciprocal device of a kind of multiport input and output, and its effect is that light signal can only be transmitted along the port order of regulation, and this characteristics of non-reciprocity utilizes the Faraday effect of magneto-optic memory technique to realize.
Further, in order to better feature bragg wavelength be conducted to reflection-type Bragg grating wavelength demodulating unit 41 by optical fiber circulator 31, optical fiber circulator 31 in the embodiment of the present invention is preferably: insertion loss≤0.7dB, return loss >=60dB, this optical fiber circulator 31 has the feature such as high-isolation, low insertion loss.
Embodiment 2
When the complex parameter demodulating unit 4 in complex parameter monitoring system is transmission-type demodulating unit, see Fig. 3, this complex parameter monitoring system comprises: tunable optical source 1, fibre optic isolater 2, host computer 5, wherein, complex parameter sensing unit 3 comprises: Bragg grating sensing unit 32 and Mach-Zehnder interfere type voice sending sensor unit 33, and complex parameter demodulating unit 4 comprises: transmission-type Bragg grating wavelength demodulating unit 43 and Mach-Zehnder acoustic emission light intensity demodulating unit 42;
The light beam that tunable optical source 1 sends directly arrives Bragg grating sensing unit 32 after fibre optic isolater 2, the feature bragg wavelength of this Bragg grating sensing unit 32 conducts to transmission-type Bragg grating wavelength demodulating unit 43 by Mach-Zehnder interfere type voice sending sensor unit 33, obtains ambient temperature situation and strain conditions by demodulation feature bragg wavelength; Ambient temperature situation and strain conditions are transferred to host computer 5 by transmission-type Bragg grating wavelength demodulating unit 43; All the other spectrum through Bragg grating sensing unit 32 provide incident light for Mach-Zehnder interfere type voice sending sensor unit 33, change the light intensity of incident light, Mach-Zehnder acoustic emission light intensity demodulating unit 42 obtains light intensity signal, light intensity signal is converted to electric signal, and by electric signal transmission to host computer 5; The host computer 5 to external world power of temperature regime, strain conditions, acoustic emission signal and frequency is analyzed, and obtains testee structural intergrity situation.
Embodiment 3
When the complex parameter demodulating unit 4 in complex parameter monitoring system is transmission-type demodulating unit, see Fig. 4, this complex parameter monitoring system comprises: tunable optical source 1, fibre optic isolater 2, host computer 5, wherein, complex parameter sensing unit 3 comprises: Bragg grating sensing unit 32, Mach-Zehnder interfere type voice sending sensor unit 33 and coupling mechanism 34, and complex parameter demodulating unit 4 comprises: transmission-type Bragg grating wavelength demodulating unit 43 and Mach-Zehnder acoustic emission light intensity demodulating unit 42;
The light beam that tunable optical source 1 sends directly is divided into first via light beam and the second road light beam after fibre optic isolater 2 and coupling mechanism 34; First via light beam arrives Bragg grating sensing unit 32, the feature bragg wavelength of this Bragg grating sensing unit 32 conducts to transmission-type Bragg grating wavelength demodulating unit 43, obtains ambient temperature situation and strain conditions by the change of demodulation feature bragg wavelength; Ambient temperature situation and strain conditions are transferred to host computer 5 by transmission-type Bragg grating wavelength demodulating unit 43; Second road light beam provides incident light for Mach-Zehnder interfere type voice sending sensor unit 33, change the light intensity of incident light, Mach-Zehnder acoustic emission light intensity demodulating unit 42 obtains light intensity signal, and light intensity signal is converted to electric signal, and by electric signal transmission to host computer 5; The host computer 5 to external world power of temperature regime, strain conditions, acoustic emission signal and frequency is analyzed, and obtains testee structural intergrity situation.
Embodiment 4
When the complex parameter demodulating unit 4 in complex parameter monitoring system is transmission-type demodulating unit, see Fig. 5, this complex parameter monitoring system comprises: tunable optical source 1, fibre optic isolater 2, host computer 5, wherein, complex parameter sensing unit 3 comprises: Bragg grating sensing unit 32, Mach-Zehnder interfere type voice sending sensor unit 33 and coupling mechanism 34, and complex parameter demodulating unit 4 comprises: transmission-type Bragg grating wavelength demodulating unit 43 and Mach-Zehnder acoustic emission light intensity demodulating unit 42;
The light beam that tunable optical source 1 sends is divided into the 3rd road light beam and the 4th road light beam after fibre optic isolater 2, Bragg grating sensing unit 32 and coupling mechanism 34, feature bragg wavelength in 3rd road light beam transfers to transmission-type Bragg grating wavelength demodulating unit 43 by coupling mechanism 34, obtains ambient temperature situation and strain conditions by the change of demodulation feature bragg wavelength; Ambient temperature situation and strain conditions are transferred to host computer 5 by transmission-type Bragg grating wavelength demodulating unit 43; 4th road light beam provides incident light for Mach-Zehnder interfere type voice sending sensor unit 33, change the light intensity of incident light, Mach-Zehnder acoustic emission light intensity demodulating unit 42 obtains light intensity signal, and light intensity signal is converted to electric signal, and by electric signal transmission to host computer 5; The host computer 5 to external world power of temperature regime, strain conditions, acoustic emission signal and frequency is analyzed, and obtains testee structural intergrity situation.
Wherein, see Fig. 6, the Mach-Zehnder acoustic emission light intensity demodulating unit 42 in embodiment 1,2,3 and 4 specifically comprises: photodetector 421 and data collecting card 422,
Photodetector 421 obtains light intensity signal, and light intensity signal is converted to electric signal, and passes through data collecting card 422 by electric signal transmission to host computer 5.
Further, in order to better meet the needs of incident optical power, the coupling mechanism 34 in embodiment 3 and 4 is preferably 1 × 2 type coupling mechanism, and the emergent light of tunable optical source 1 is divided into two-way light according to the power ratio of 50:50 after 1 × 2 type coupling mechanism.
Grating itself adopts Ultra-Violet Laser phase mask technique to make, centre wavelength 1550nm, grating length is less than 14mm, FWHM(light beam pulse halfwidth degree) be less than 0.3nm, reflectivity is greater than 80%, grating temperature and the coefficient of strain: conversion coefficient 10pm/ DEG C, conversion coefficient 1.2pm/ μ ε, raster center wavelength measurement environment: constant temperature workshop 20 DEG C.Because temperature and stress all can cause the change of feature bragg wavelength, therefore can select the compensation schemes of Bragg grating sensing unit 32 to obtain strain detecting result more accurately according to testing requirement when reality uses, or strain and temperature biparameter value are measured simultaneously.
Bragg grating sensing unit 32 adopts Wavelength demodulation mode, inherently eliminates the interference that light intensity fluctuation causes, and antijamming capability is strong, can realize distant signal transmission.And all belong to tempolabile signal due to temperature and strain, therefore require also not high to the frequency, demodulation frequency of Bragg grating sensing unit 32, can realize completely in actual applications.
Because Bragg grating sensing unit 32 and Mach-Zehnder interfere type voice sending sensor unit 33 are respectively based on wavelength-modulated and the intensity modulated of light signal, therefore two sensing units can not conflict mutually, measure while can realizing ambient temperature situation, strain conditions, the power of acoustic emission signal and frequency.
The effect of tunable optical source 1 is for the normal work of system provides reliable and stable spectrum, the spectrum of the tunable optical source 1 selected can cover the wavelength variation range of Bragg grating sensing unit 32, measure the temperature of key position and the changing condition of strain better, can ensure that again spectrum is in a narrower frequency band range, is conducive to the normal work of Mach-Zehnder interfere type voice sending sensor unit 33.
Mach-Zehnder acoustic emission light intensity demodulating unit 42 small volume, sensitivity is very high, and the acoustic emission signal be particularly suitable in less spatial dimension detects.The detection wavelength coverage of photodetector 421 is 800 ~ 1700nm, and maximum peak power is 70mW, and minimum rise time and fall time are 100 psecs.
The feasibility of a kind of complex parameter monitoring system that the embodiment of the present invention provides is verified below with a concrete test, first build Hsu-Nielsen to break plumbous standard test system, and place two electromagnetic ovens and the switch controlling electromagnetic oven to simulate strong electromagnetic interference environment.As everyone knows, see Fig. 7, Hsu-Nielsen break plumbous standard test produce acoustic emission signal type be burst acoustic emission signal.Disconnected plumbous experiment is carried out under strong electromagnetic interference environment, obtain the sensing effect of piezoelectric type calibrate AE sensor and Mach-Zehnder interfere type voice sending sensor unit 33 respectively as shown in FIG. 8 and 9, by known with the typical burst acoustic emission signal comparison of wave shape shown in Fig. 7, strong electromagnetic environment considerably increases the ground unrest of piezoelectric type calibrate AE sensor, and the severe jamming actual sensing effect of signal; And the acoustic emission signal signal to noise ratio (S/N ratio) that Mach-Zehnder interfere type voice sending sensor unit 33 obtains is better, and meet typical burst acoustic emission signal waveform.This test illustrates that the antijamming capability based on Mach-Zehnder interfere type voice sending sensor unit 33 pairs of strong electromagnetic environment of Fibre Optical Sensor mechanism is comparatively strong, greatly can expand the range of application of acoustic emission.
In sum, embodiments provide a kind of complex parameter monitoring system, the acoustic emission signal of the coupling unit after this system adopts Mach-Zehnder interfere type voice sending sensor unit inspection and testee to fit, is suitable for damascene structures monitoring and integrity assessment; This Mach-Zehnder interfere type voice sending sensor unit be connected in series with optical fiber Bragg grating sensor or and connect, be easy to realize Distributed Detection; Verify by experiment, the anti-electromagnetic interference capability of native system is strong, achieves long-distance transmissions.
It will be appreciated by those skilled in the art that accompanying drawing is the schematic diagram of a preferred embodiment, the invention described above embodiment sequence number, just to describing, does not represent the quality of embodiment.
The foregoing is only preferred embodiment of the present invention, not in order to limit the present invention, within the spirit and principles in the present invention all, any amendment done, equivalent replacement, improvement etc., all should be included within protection scope of the present invention.
Claims (9)
1. a complex parameter monitoring system, described complex parameter monitoring system comprises: tunable optical source, fibre optic isolater, complex parameter sensing unit, complex parameter demodulating unit and host computer,
The light beam that described tunable optical source sends transfers to described complex parameter sensing unit through described fibre optic isolater, is modulated the feature bragg wavelength in described complex parameter sensing unit by the change of ambient temperature and strain; The light intensity of acoustic emission signal situation to incident light according to measured place is modulated, and obtains the rear light signal of modulation; Described complex parameter demodulating unit carries out demodulation by the feature bragg wavelength after modulation, obtains ambient temperature situation and strain conditions; Demodulation is carried out to light signal after described modulation, obtains power and the frequency of acoustic emission signal; By described host computer, the power of described ambient temperature situation, described strain conditions, described acoustic emission signal and frequency are analyzed, obtain testee structural intergrity situation, it is characterized in that,
When the described complex parameter demodulating unit in described complex parameter monitoring system is reflection-type demodulating unit, described complex parameter monitoring system comprises: described tunable optical source, described fibre optic isolater, described host computer,
Wherein, described complex parameter sensing unit comprises: optical fiber circulator, Bragg grating sensing unit and Mach-Zehnder interfere type voice sending sensor unit, and described complex parameter demodulating unit comprises: reflection-type Bragg grating wavelength demodulating unit and Mach-Zehnder acoustic emission light intensity demodulating unit;
The light beam that described tunable optical source sends is through described fibre optic isolater, described Bragg grating sensing unit is arrived according to the port order of described optical fiber circulator, the feature bragg wavelength of described Bragg grating sensing unit conducts to described reflection-type Bragg grating wavelength demodulating unit by described optical fiber circulator, obtains described ambient temperature situation and described strain conditions by the change of feature bragg wavelength described in demodulation; Described ambient temperature situation and described strain conditions are transferred to described host computer by described reflection-type Bragg grating wavelength demodulating unit; All the other spectrum through described Bragg grating sensing unit provide incident light for described Mach-Zehnder interfere type voice sending sensor unit, acoustic emission signal modulates described incident light, change the light intensity of described incident light, described Mach-Zehnder acoustic emission light intensity demodulating unit obtains light intensity signal, described light intensity signal is converted to electric signal, and by described electric signal transmission to host computer; Described host computer is analyzed the power of described ambient temperature situation, described strain conditions, described acoustic emission signal and frequency, obtains described testee structural intergrity situation.
2. a kind of complex parameter monitoring system according to claim 1, it is characterized in that, described optical fiber circulator is specially: insertion loss≤0.7dB, return loss >=60dB.
3. a complex parameter monitoring system, described complex parameter monitoring system comprises: tunable optical source, fibre optic isolater, complex parameter sensing unit, complex parameter demodulating unit and host computer,
The light beam that described tunable optical source sends transfers to described complex parameter sensing unit through described fibre optic isolater, is modulated the feature bragg wavelength in described complex parameter sensing unit by the change of ambient temperature and strain; The light intensity of acoustic emission signal situation to incident light according to measured place is modulated, and obtains the rear light signal of modulation; Described complex parameter demodulating unit carries out demodulation by the feature bragg wavelength after modulation, obtains ambient temperature situation and strain conditions; Demodulation is carried out to light signal after described modulation, obtains power and the frequency of acoustic emission signal; By described host computer, the power of described ambient temperature situation, described strain conditions, described acoustic emission signal and frequency are analyzed, obtain testee structural intergrity situation, it is characterized in that,
When the described complex parameter demodulating unit in described complex parameter monitoring system is transmission-type demodulating unit, described complex parameter monitoring system comprises: described tunable optical source, described fibre optic isolater, described host computer,
Wherein, described complex parameter sensing unit comprises: Bragg grating sensing unit and Mach-Zehnder interfere type voice sending sensor unit, and described complex parameter demodulating unit comprises: transmission-type Bragg grating wavelength demodulating unit and Mach-Zehnder acoustic emission light intensity demodulating unit;
The light beam that described tunable optical source sends directly arrives described Bragg grating sensing unit after described fibre optic isolater, the feature bragg wavelength of described Bragg grating sensing unit to described transmission-type Bragg grating wavelength demodulating unit, obtains described ambient temperature situation and described strain conditions by feature bragg wavelength described in demodulation by described Mach-Zehnder interfere type voice sending sensor cell conducts; Described ambient temperature situation and described strain conditions are transferred to described host computer by described transmission-type Bragg grating wavelength demodulating unit; All the other spectrum through described Bragg grating sensing unit provide incident light for described Mach-Zehnder interfere type voice sending sensor unit, change the light intensity of described incident light, described Mach-Zehnder acoustic emission light intensity demodulating unit obtains light intensity signal, described light intensity signal is converted to electric signal, and by described electric signal transmission to described host computer; Described host computer is analyzed the power of described ambient temperature situation, described strain conditions, described acoustic emission signal and frequency, obtains described testee structural intergrity situation.
4. a complex parameter monitoring system, described complex parameter monitoring system comprises: tunable optical source, fibre optic isolater, complex parameter sensing unit, complex parameter demodulating unit and host computer,
The light beam that described tunable optical source sends transfers to described complex parameter sensing unit through described fibre optic isolater, is modulated the feature bragg wavelength in described complex parameter sensing unit by the change of ambient temperature and strain; The light intensity of acoustic emission signal situation to incident light according to measured place is modulated, and obtains the rear light signal of modulation; Described complex parameter demodulating unit carries out demodulation by the feature bragg wavelength after modulation, obtains ambient temperature situation and strain conditions; Demodulation is carried out to light signal after described modulation, obtains power and the frequency of acoustic emission signal; By described host computer, the power of described ambient temperature situation, described strain conditions, described acoustic emission signal and frequency are analyzed, obtain testee structural intergrity situation, it is characterized in that,
When the described complex parameter demodulating unit in described complex parameter monitoring system is transmission-type demodulating unit, described complex parameter monitoring system comprises: described tunable optical source, described fibre optic isolater, described host computer,
Wherein, described complex parameter sensing unit comprises: Bragg grating sensing unit, Mach-Zehnder interfere type voice sending sensor unit and coupling mechanism, and described complex parameter demodulating unit comprises: transmission-type Bragg grating wavelength demodulating unit and Mach-Zehnder acoustic emission light intensity demodulating unit;
The light beam that described tunable optical source sends directly is divided into first via light beam and the second road light beam after described fibre optic isolater and described coupling mechanism; Described first via light beam arrives described Bragg grating sensing unit, the feature bragg wavelength of described Bragg grating sensing unit conducts to described transmission-type Bragg grating wavelength demodulating unit, obtains described ambient temperature situation and described strain conditions by the change of demodulation feature bragg wavelength; Described ambient temperature situation and described strain conditions are transferred to described host computer by described transmission-type Bragg grating wavelength demodulating unit; Described second road light beam provides incident light for described Mach-Zehnder interfere type voice sending sensor unit, change the light intensity of described incident light, described Mach-Zehnder acoustic emission light intensity demodulating unit obtains light intensity signal, described light intensity signal is converted to electric signal, and by described electric signal transmission to described host computer; Described host computer is analyzed the power of described ambient temperature situation, described strain conditions, described acoustic emission signal and frequency, obtains described testee structural intergrity situation.
5. a complex parameter monitoring system, described complex parameter monitoring system comprises: tunable optical source, fibre optic isolater, complex parameter sensing unit, complex parameter demodulating unit and host computer,
The light beam that described tunable optical source sends transfers to described complex parameter sensing unit through described fibre optic isolater, is modulated the feature bragg wavelength in described complex parameter sensing unit by the change of ambient temperature and strain; The light intensity of acoustic emission signal situation to incident light according to measured place is modulated, and obtains the rear light signal of modulation; Described complex parameter demodulating unit carries out demodulation by the feature bragg wavelength after modulation, obtains ambient temperature situation and strain conditions; Demodulation is carried out to light signal after described modulation, obtains power and the frequency of acoustic emission signal; By described host computer, the power of described ambient temperature situation, described strain conditions, described acoustic emission signal and frequency are analyzed, obtain testee structural intergrity situation, it is characterized in that,
When the described complex parameter demodulating unit in described complex parameter monitoring system is transmission-type demodulating unit, described complex parameter monitoring system comprises: described tunable optical source, described fibre optic isolater, described host computer,
Wherein, described complex parameter sensing unit comprises: Bragg grating sensing unit, Mach-Zehnder interfere type voice sending sensor unit and coupling mechanism, and described complex parameter demodulating unit comprises: transmission-type Bragg grating wavelength demodulating unit and Mach-Zehnder acoustic emission light intensity demodulating unit;
The light beam that described tunable optical source sends is divided into the 3rd road light beam and the 4th road light beam after described fibre optic isolater, described Bragg grating sensing unit and described coupling mechanism, feature bragg wavelength in described 3rd road light beam to described transmission-type Bragg grating wavelength demodulating unit, obtains ambient temperature situation and strain conditions by the change of demodulation feature bragg wavelength by described coupler transfer; Described ambient temperature situation and described strain conditions are transferred to described host computer by described transmission-type Bragg grating wavelength demodulating unit; Described 4th road light beam provides incident light for described Mach-Zehnder interfere type voice sending sensor unit, change the light intensity of described incident light, described Mach-Zehnder acoustic emission light intensity demodulating unit obtains light intensity signal, described light intensity signal is converted to electric signal, and by described electric signal transmission to described host computer; Described host computer is analyzed the power of described ambient temperature situation, described strain conditions, described acoustic emission signal and frequency, obtains described testee structural intergrity situation.
6. a kind of complex parameter monitoring system according to claim 1 or 3 or 4 or 5, is characterized in that, pass through Fiber connection between described complex parameter sensing unit and described complex parameter demodulating unit.
7. a kind of complex parameter monitoring system according to claim 6, it is characterized in that, described optical fiber is specially: SMF-28 type single-mode fiber.
8. a kind of complex parameter monitoring system according to claim 1 or 3 or 4 or 5, is characterized in that, described Mach-Zehnder acoustic emission light intensity demodulating unit specifically comprises: photodetector and data collecting card,
Described photodetector obtains described light intensity signal, and described light intensity signal is converted to described electric signal, and by described data collecting card by described electric signal transmission extremely described host computer.
9. a kind of complex parameter monitoring system according to claim 4 or 5, it is characterized in that, described coupling mechanism is specially: 1 × 2 type coupling mechanism.
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