CN105043458B - A kind of fibrous composite lightning damage on-line measuring device and method - Google Patents
A kind of fibrous composite lightning damage on-line measuring device and method Download PDFInfo
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Abstract
The invention discloses a kind of fibrous composite lightning damage on-line measuring device and method, device includes：Including double lead array optical fiber temperature grating, double lead array strain fiber grating, two fiber couplers, fiber Bragg grating (FBG) demodulator and processors, every two ends of fiber grating are as lead, (FBG) demodulator is connected by coupler, form two independent optical signals passages, after optical fiber is subjected to thunderbolt fracture, double lead fiber grating can be used as two independent single wire fiber gratings.Grating is embedded in composite inner, and temperature, the strain of composite material structural member are detected by center wavelength shift, using lightning damage detecting system software data processing, forms the distributed in three dimensions result of composite material structural member lightning damage degree, and output display.The present invention solve traditional lightning stroke process it is of short duration be difficult to catch, the damage sensor that is struck by lightning, transient electromagnetic field Interference Detection system, the problem of the on-line checking such as lightning surge damage detector.
Description
Technical field
The present invention relates to a kind of fibrous composite lightning damage on-line measuring device and method.
Background technology
Fibrous composite have high intensity, low-density, it is corrosion-resistant, antifatigue many advantages, such as, be Aero-Space preferable
Structural material, has been widely used in aerospace flight vehicle at present, especially in aircraft structure, plays extremely important work
With.For example, composite consumption alreadys exceed 50% in Boeing 787 and Air Passenger A350XWB aircrafts, major part is fine carbon among these
Dimension composite and glass fiber compound material.
According to statistics, China suffers from 1 thunderbolt for 3000 hours per airplane average flight in statistical significance, in thunderstorm
Prone areas are flown, and being subjected to lightning strike probability can improve several times.Fibrous composite replaces metal material, and intensity is improved, and quality subtracts
Gently, but electrical and thermal conductivity be not so good as metal material, after being struck by lightning be easier damage.Aircraft occurs three kinds of damages after being struck by lightning
Condition of the injury condition：Slight damage, heavier damage and major injury.Slight damage can then continue flight, be overhauled after can landing；Heavier damage
Wound needs to land immediately and repairs or make a return voyage；Major injury is likely to result in fatal crass.Aircraft be struck by lightning after fatal crass
Accident is of common occurrence.
Thunderstorm causes serious potential safety hazard to aircraft flight, but aircraft flies in the air, it is impossible to how take shelter from the thunder completely
Degree of injury after the process be struck by lightning of on-line monitoring Aircraft Composite Structure part and thunderbolt, to decide whether to return immediately
Boat maintenance, this is significant for aircraft safety and operation cost, enjoys Air Branch to pay close attention to.On-line checking composite
Lightning damage position, damaged area, lesion depths, and the residual intensity after composite material structural member is struck by lightning is assessed, it is right
Flight Safety has extremely important practical value.
Thunder and lightning is the forceful electric power magnetic phenomenon that a kind of moment (hundreds of microseconds) occurs, and electric current is huge (up to 200kA), it is difficult to do
To on-line checking.Be conventionally used to composite lightning damage detection sensor mainly has three defects when in use：(1) using biography
Used as signal, thunderbolt can produce huge transient electromagnetic field, interference signal transmission, or sensor electricity to sensor micro-current when occurring
Road can produce induced-current, or lightning current to enter sensor loop, cause whole sensor, detector circuit to be subjected to thunder and lightning
Surge is destroyed；(2) traditional sensors itself are affixed on aircraft surfaces or implantation is internal, and detection is difficult if aircraft surfaces are affixed on
Material internal is damaged, and be vulnerable to be struck by lightning directly damage, and aircaft configuration inside is embedded in advance can produce shadow to composite material strength
Ring, easily cause stress concentration；(3) almost all of sensor is directly subjected to thunderbolt and can all damage, and loses detection function.Sensing
Device is not influenceed by the transient electromagnetic field of thunder and lightning, can still be survived after running into thunderbolt, can detect that composite inner is damaged, but
Composite material structural member intensity will not be produced and significantly affected, as the important of composite material structural member lightning damage on-line checking
Precondition.
The content of the invention
The present invention is in order to solve the above problems, it is proposed that a kind of fibrous composite lightning damage on-line measuring device and side
Method, the present apparatus is sensor using double lead arrayed optical fiber grating, and the composite inner after real-time monitoring is struck by lightning is damaged
Wound, effectively solves that traditional lightning stroke process is of short duration to be difficult to catch, be struck by lightning and damage sensor, transient electromagnetic field Interference Detection system
The problem of the on-line checkings such as system, lightning surge damage detector.
To achieve these goals, the present invention is adopted the following technical scheme that：
A kind of fibrous composite lightning damage on-line measuring device, including it is double lead array optical fiber temperature grating, double
Cord array formula strain fiber grating, two fiber couplers, fiber Bragg grating (FBG) demodulator and processors, wherein：Light source is produced and swashed
Optical signal, laser signal is divided into two-way by conduction optical fiber, and the first fiber coupler and the second fiber coupler are transferred to respectively,
First fiber coupler connects double lead array optical fiber temperature grating and one end of double lead array strain fiber grating is drawn
The other end lead of line, double lead array optical fiber temperature grating and double lead array strain fiber grating connects the second optical fiber
Coupler, forms two ports for having laser light incident and reflection concurrently；Double lead array optical fiber temperature grating, double lead array
The all fiber gratings for straining fiber grating are embedded in inside composite material structural member in advance, and laser signal is mutual with fiber grating
After effect, reflection laser is again introduced into first, second fiber coupler, first, second fiber coupling by two ends lead respectively
The optical signal of device output enters fiber Bragg grating (FBG) demodulator, completes signal demodulation, fiber Bragg grating (FBG) demodulator connection processor, processor
According to the result of signal analysis fibrous composite type of impairment, degree and its distribution.
The double lead array optical fiber temperature grating is parallel with double lead array strain fiber grating, arranged adjacent,
Each temperature raster unit and double lead array in double lead array optical fiber temperature grating strain each of fiber grating
Strain raster unit is corresponded, so that optical fiber temperature constitutes one with two corresponding gratings on adjacent strain optical fiber
Double lead fiber grating pair.
The light source is the laser being built in fiber Bragg grating (FBG) demodulator, and laser produces continuous frequency modulation laser, passes through
Lead enters double lead array optical fiber temperature grating, double lead array strain fiber grating, forms the reflected signal of stabilization.
The double lead array optical fiber temperature grating, double lead array strain fiber grating are double lead structure,
I.e. each grating has two leads to be connected, and two leads can be as the signalling channel of raster unit, as long as each grating
There is a bars passage just to can be used for signal detection；Even if the grating damage fracture in lightning stroke process, as long as grating also has
Lead is connected with external detection system, it is possible to keep optical fibre channel, it is ensured that the survival of fiber grating and the transmission of detection signal.
The double lead array optical fiber temperature, double lead array strain optical fiber are all carved with cardiac wave in difference including multiple
Raster unit long, each raster unit is an independent sensor unit.
The processor, including Geometric Modeling module, fiber grating signal resolution module, damage of composite materials database and
Lightning damage inverting graphical interfaces, wherein, the Geometric Modeling module, for being modeled to composite material structural member, multiple
The accurate position for marking raster unit in condensation material geometrical model；The fiber grating signal resolution module, for analytical calculation
The wavelength signals that fiber Bragg grating (FBG) demodulator is transmitted, obtain temperature, the strain and stress of fiber composite structure part, by it
Judge type of impairment and degree of injury with the information contrast stored in damage of composite materials database；The lightning damage is anti-
Graphical interfaces is drilled, for being finally inversed by composite lightning damage distributed in three dimensions situation and exporting.
A kind of detection method based on said apparatus, comprises the following steps：
(1) before composite curing molding, as needed according to the spacing laying double lead battle array of setting in structural member
Column optical fiber temperature grating, double lead array strain fiber grating；
(2) composite material structural member curing molding, fiber-optic grating sensor is embedded in inside composite material structural member, even
Connect the first fiber coupler, the second fiber coupler, fiber Bragg grating (FBG) demodulator and processor；
(3) after light source produces laser signal, laser signal to enter the first fiber coupler, the second fiber coupler, respectively
Double lead array optical fiber temperature grating, double lead array are entered by two ends lead and strains fiber grating region, through grating
Signal after reflection returns to grating signal (FBG) demodulator through the first fiber coupler, the second fiber coupler, and optical signal is demodulated to
Data signal is processed into processor；
(4) 3-D geometric model of composite material structural member is set up by Geometric Modeling module, raster unit numbering is logical
Coordinate relationship marking is crossed on the threedimensional model of composite material structural member；Grating signal parsing module parses grating signal (FBG) demodulator
The signal that transmission comes, according to the information that double lead array optical fiber temperature grating, double lead array strain fiber grating are gathered,
Obtain composite strain, temperature and STRESS VARIATION；
(5) call composite lightning damage database, identification of damage type and judge degree of injury, acquisition raster unit
Type of impairment and degree, are passed through stop position data inversion by the type of impairment and degree of composite regional area where numbering
Onto geometrical model, the dynamic solid distribution map of composite lightning damage is obtained.
In the step (1), specific method is：Before composite curing molding, in structural member as needed according to
The n fiber grating pair of grating sensor is carved with certain spacing laying m, optical fiber is marked as 1,2,3, m, grating
Element numerals are 1,2,3, n, to above there is two fiber gratings, one is the optical fiber temperature of measurement temperature to each grating
Grating, labeled as T, another is the strain fiber grating of measuring strain, labeled as S, constitutes double arrayed optical fiber grating sensings
Device.
In the step (4), when thunderbolt energy is low, fiber grating is intact, and two ends lead collects grating sensor unit
Signal is identical, using either end signal detection, causes damage of composite materials serious to thunderbolt energy, causes fibercuts, double
Wire fiber grating becomes two single wire fiber gratings, and grating sensor still can be detected and be transmitted signal, now
The signal of two ends lead transmission is intended to detection process, and raster unit area is determined by the signal difference for contrasting two lead port transmissions
Whether damage, and determine position, the quantity in the raster unit area of damage.
In the step (5), realized to measured detection, in expression grating by the drift for measuring raster center wavelength
Cardiac wave is long, and raster center wavelength is strained and temperature-responsive with the drift of stress and temperature.
In the step (5), the temperature computation method of composite is：By measuring the optical fiber temperature light under different temperatures
The centre wavelength in the case of centre wavelength and strain optical fiber grating temperature demarcation in the case of grid demarcation, is then fitted centre wavelength
With the linear relationship of temperature, grating temperature coefficient is obtained, then obtain the temperature of composite.
In the step (5), the strain calculation method of composite is：According to the change of strain fiber bragg grating center wavelength
The fitting function difference equation that amount and optical fiber temperature grating and strain optical fiber grating temperature are demarcated, calculates the strain of composite
Amount, bonded composite modulus calculates composite stress.
Beneficial effects of the present invention are：
(1) the invention provides a kind of composite lightning damage on-line measuring device, traditional lightning stroke process is solved
It is of short duration to be difficult to catch, be struck by lightning and damage the online inspections such as sensor, transient electromagnetic field Interference Detection system, lightning surge damage detector
The problem of survey；
(2) present invention uses double lead fiber-optic grating sensor, and composite material structural member strength and stiffness are hardly produced
Raw influence, while can detect that composite inner is damaged.After being struck by lightning, double lead fiber-optic grating sensor can become two
Individual independent single wire fiber grating sensor, after composite material structural member is damaged survive fiber-optic grating sensor according to
So can be with normal work；
(3) the invention provides composite lightning damage on-line checking and the method for signal transacting, by lightning stroke process
In strain, the change detection lightning damage situation of temperature, and the type of impairment of stereoscopic display composite material structural member directly perceived and
Degree of injury is distributed.
Brief description of the drawings
Fig. 1 is the FBG detection means schematic diagrames of composite material structural member lightning damage；
Fig. 2 becomes two independent single wire fiber grating schematic diagrams after being struck by lightning for double lead fiber grating；
Fig. 3 is the schematic diagram of double lead arrayed optical fiber grating pair；
Fig. 4 is the demarcation and matched curve of the centre wavelength and temperature relation of grating；
Fig. 5 (a) is the raster center wavelength change of fiber-optic grating sensor measurement composite thunderbolt temperature-fall period；
Fig. 5 (b) is the temperature change of fiber-optic grating sensor measurement composite thunderbolt temperature-fall period.
Specific embodiment：
The invention will be further described with embodiment below in conjunction with the accompanying drawings.
A kind of composite lightning damage on-line measuring device, the device is to sense with double lead arrayed optical fiber grating
Device, monitors the change of the strain, stress and temperature of composite material structural member lightning stroke process on-line, by the computer of lightning damage
Aided detection software is processed Bragg grating signals, judges lightning damage type, calculates lightning damage degree.
Double lead arrayed optical fiber grating two double lead fiber gratings to being made up of：One optical fiber temperature grating and one
Strain fiber grating, optical fiber temperature grating is used for measurement temperature, and strain fiber grating is used for measuring strain.Two optical fiber parallels
Arrange and adjacent, drawn with double lead, constitute a double lead fiber grating pair.
It is mainly as the advantage of sensor from double lead fiber grating pair：Fiber grating uses double lead structure, meets with
After being broken by thunderbolt, 1 double lead fiber-optic grating sensor can become 2 single wire fiber grating sensors, still can be with
Play sensor effect.Fiber grating can detect strain and the temperature change of composite, and calculate the STRESS VARIATION of material,
Can be with accurate characterization composite lightning damage process by the change of strain, stress and temperature.Fiber grating diameter is only suitable
Influence is not almost produced on composite property inside the several times of carbon fiber diameter, embedment fibrous composite.Additionally, optical fiber
It is sensed signal sources that grating uses optical signal, is not disturbed by Lightning Electromagnetic Fields.
A kind of composite lightning damage on-line measuring device concrete structure mainly includes：Double lead arrayed optical fiber grating
To, fiber coupler, fiber Bragg grating (FBG) demodulator (built-in laser), computer etc..
The built-in laser of fiber Bragg grating (FBG) demodulator produces laser signal, is divided into two paths of A, B and enters by conduction optical fiber
Fiber coupler A and fiber coupler B, fiber coupler A connect the A ends lead of double lead fiber grating, and fiber coupler B connects
The B ends lead of double lead fiber grating is connect, two ports for having laser light incident and reflection concurrently are formed.Fiber grating is embedded in compound
Material internal, after laser signal and grating interact, reflection laser respectively by A, B lead be again introduced into fiber coupler A,
B, the signal for going out coupler returns to fiber Bragg grating (FBG) demodulator, and the data signal that computer can be recognized is become after optical signal demodulation,
By the working process of the computer aided detection software of lightning damage, type of impairment, degree are formed in a computer and its is divided
The result of cloth, and output display.
The built-in laser of fiber Bragg grating (FBG) demodulator can produce continuous frequency modulation laser, laser signal to enter by lead
Bragg gratings, form the reflected signal of stabilization.
To being double lead structure, i.e., each grating has two leads to be connected to double lead arrayed optical fiber grating, each light
Grid have two light paths, even if the grating damage fracture in lightning stroke process, as long as grating also has a lead and external detection system
System connection, it is possible to keep optical fibre channel, it is ensured that the survival of fiber grating and the transmission of detection signal.
Double lead arrayed optical fiber grating two double lead fiber gratings to being made up of：One optical fiber temperature grating and one
Strain fiber grating, optical fiber temperature grating is used for measurement temperature, and strain fiber grating is used for measuring strain.Two optical fiber it is parallel and
Adjacent, raster unit is corresponded, and is drawn with double lead, constitutes a double lead fiber grating pair.
Double lead arrayed optical fiber grating, the preferably cladding diameter 35-45 microns optical fiber fabrication array of even more thin footpath
Fiber grating, the grating of thinner diameter can to a greater degree reduce influence of the optical fiber embedding to composite material strength and rigidity.
Scribe the 1-20 raster unit of different centre wavelengths on every optical fiber, preferably 6-16 raster unit, each
Raster unit is an independent sensor unit, and a plurality of optical fiber for having scribed multiple gratings may make up optical fiber optical grating array.
Double lead arrayed optical fiber grating can detect strain and the temperature change of composite material structural member lightning stroke process, with reference to
Material parameter, can calculate the STRESS VARIATION of material lightning stroke process.
Coupler is fiber grating signal coupler, and the characteristic with excellent wavelength selective power and multiport is knot
Structure is compact, loss is small, polarize unrelated fiber coupler.
Fiber Bragg grating (FBG) demodulator is high-speed high frequency optic fiber grating wavelength (FBG) demodulator, the demodulation with high speed and multi-channel parallel
Scheme, realizes signal fast demodulation, meets thunderbolt detection needs.Fiber Bragg grating (FBG) demodulator is connected with computer by data wire,
The optical signal fast demodulation that grating after thunderbolt moment and thunderbolt is returned is data signal.
Computer be furnished with lightning damage inspection software, software include Geometric Modeling module, fiber grating signal resolution module,
Damage of composite materials database and lightning damage inverting graphical interfaces.By the Geometric Modeling module of software to composite structure
Part is modeled, the accurate position for marking raster unit in composite geometrical model；Signal demodulation module analytical calculation optical fiber light
The wavelength signals that grid (FBG) demodulator is transmitted, obtain temperature, the strain and stress of fiber composite structure part, then and compound
Material damage database is contrasted, for judging type of impairment and degree of injury.Composite is finally inversed by by graphical interfaces to be struck by lightning
Distributed in three dimensions situation is damaged, in graphical interfaces output.
To achieve the above object, the present invention provides the device and carries out the side of fibrous composite lightning damage on-line checking
Method, step is as follows：
(1) the optical fiber inscribing fiber grating of 35-45 microns of cladding diameter of selection even more thin footpath, every optical fiber scribes multiple
Raster unit, raster unit is marked as 1,2,3, n, lead draws from sensors A, B two ends respectively, and to grating
Temperature coefficient is demarcated.
(2) two fiber gratings are selected to set up fiber grating pairs, a fiber grating is used for measurement temperature, labeled as T, separately
One fiber grating measuring strain, labeled as S, marks the optical fiber temperature grating tiny stainless steel tube of equal overcoat of T, mouth of pipe glue envelope.
(3) before composite curing molding, light is carved with according to certain spacing laying m as needed in structural member
The fiber grating pair of gate sensor, optical fiber is marked as 1,2,3, m, each grating is to above there is an optical fiber temperature grating
With a strain fiber grating, there is n sensor unit (raster unit) on every optical fiber, constitute double array (temperature matrices T
[m × n] and strain matrix S [m × n]) fiber-optic grating sensor.
(4) protection fiber grating lead is wrapped up with plastic tape, according to technique, composite material structural member curing molding, light
Fiber grating sensor is embedded in inside composite material structural member.
(5) after composite material structural member curing molding, every A ends lead connection fiber coupling of fiber-optic grating sensor
Each corresponding ports of device A front ends, each correspondence of the B ends lead connection fiber coupler B front ends of fiber-optic grating sensor
Port, coupler back-end ports connect computer by intelligent acess fiber Bragg grating (FBG) demodulator, grating demodulation instrument by data wire.
(6) (FBG) demodulator is opened, after built-in laser produces laser signal, laser signal to enter coupler, respectively by A, B
End lead enters grating region, and coupler is returned through the signal after optical grating reflection, and grating signal (FBG) demodulator, light letter are returned through coupler
Number being demodulated to data signal enters computer disposal.
(7) the computer aided detection software analyzing and processing (FBG) demodulator signal of lightning damage, obtains lightning damage distribution, boundary
Face output display.
Raster unit increases successively from A ends lead to B ends lead successively mark 1 to n, and centre wavelength in step 1, increment
It is 4nm.
Grating in step 2 to being made up of a temperature survey grating T and a strain measurement grating S, two optical fiber light
Grid are parallel, it is ensured that the raster unit T of optical fiber temperaturekiThe S of (i-th temperature grating of kth group grating centering) and strain gratingki(the
I-th of k group gratings centering strain grating) position is corresponding, and temperature grating needs the tiny stainless steel tube of overcoat, mouth of pipe glue envelope.
Be layered on fiber grating pair sensor inside composite material structural member before composite curing molding by step 3, is
Ensure stable performance and the survival rate of grating sensor, the laying direction of optical fiber pair try one's best with close to composite fiber paving
Layer angle is identical.
In step 6, grating demodulation instrument connects computer by data wire, and computer is soft equipped with lightning damage on-line checking
Part.The software includes that Geometric Modeling module, fiber grating signal resolution module, composite lightning damage database and thunderbolt are damaged
Hinder several big modules such as inverting graphical interfaces.
In step 7, there is selectivity to the treatment of the grating signal of the lead of grating two, due to thunder energy in lightning stroke process
Difference, the lightning damage degree produced to composite is also different；Composite material structural member diverse location damages also different, thunderbolt
Point nearby damages serious, damages lighter away from lightning strike spot position.If damage of composite materials is lighter, grating is intact, optical fiber A ends and
It is identical that B ends lead collects grating sensor cell signal, can use A, B either end signal detection.When thunderbolt energy is higher
When, damage of composite materials seriously causes fibercuts, and next double lead fiber grating of such case becomes two single lead light
Fine grating, grating sensor still can be detected and be transmitted signal, and now the end signal of A, B lead two is intended to by computer
Reason.Determine whether raster unit area damages by the signal difference for contrasting A and B leads port, and determine the raster unit of damage
The position in area, quantity.
Lightning damage inspection software detection material structure damage process is as follows in step 7：
The 3-D geometric model of composite material structural member is set up by Geometric Modeling module, raster unit numbering by sitting
Mark relationship marking is on the threedimensional model of composite material structural member；The letter that the parsing (FBG) demodulator transmission of grating signal parsing module comes
Number, obtain composite strain, temperature and STRESS VARIATION, call composite lightning damage database, identification of damage type and
Judge degree of injury；The type of impairment and degree of composite regional area where raster unit numbering are obtained, type of impairment
With degree by stop position data inversion to geometrical model, obtaining the dynamic solid distribution map of composite lightning damage,
Exported by Computer display.
The step 7 Computer signal that transmits for the treatment of (FBG) demodulator simultaneously solves composite temperature, strain and stress
Principle is as follows：
Realized to measured detection, raster center wavelength X by the drift for measuring raster center wavelengthBIt is represented by：
λB=2n Λ
Wherein, λBIt is the centre wavelength of grating；Λ is screen periods；N is refractive index.
λBIt is with the drift of temperature with stress：
Wherein, Δ λBIt is fiber bragg grating center wavelength variable quantity；ε is additional strain；Pi,jIt is the photoelastic tensor system of optical fiber
Number；V is fiber optic materials Poisson's ratio；α is the thermal coefficient of expansion of fiber optic materials；Δ T is temperature variation.
Strain and temperature-responsive result, such as following formula can be derived with reference to two formula above：
In formula, KTIt is the temperature sensitive coefficient of fiber bragg grating center wavelength drift；KεIt is fiber bragg grating center wavelength drift
Gage factor.
(1) composite temperature is calculated
The temperature grating of each fiber grating centering, the stainless steel tube of overcoat has isolated foreign material and grating sensor
Ess-strain is transmitted, and external world's strain does not produce influence to raster center wavelength, the knots modification of raster center wavelength only with material
Temperature change is relevant.Temperature grating needs to demarcate temperature coefficient, by measuring the raster center wavelength under different temperatures, then
The linear relationship of fitting centre wavelength and temperature, obtains grating temperature coefficient.
In a fiber grating pair, the centre wavelength and temperature foh relation of temperature grating and strain grating after bidding is fixed
It is as follows：
λBT1=kT1T+λ10
λBT2=kT2T+λ20
In formula, λBT1It is the centre wavelength in the case of temperature optical grating calibration；λBT2In the case of being demarcated for strain grating temperature
Centre wavelength；kT1It is the temperature coefficient of temperature grating；kT2To strain the temperature coefficient of grating；T is composite temperature.
Two close fiber optics of fiber grating centering are adjacent, position correspondence, temperature grating TkiWith strain grating SkiTemperature
It is identical, then the temperature of composite is：
By above formula, the temperature change of composite is just obtained using temperature raster center wavelength.
(2) composite strain calculation
The knots modification for straining raster center wavelength is caused jointly by the strain of temperature change and composite, is expressed as：
ΔλB2=kε2ε+kT2ΔT
In formula, kε2To strain the coefficient of strain of grating；kT2To strain the temperature coefficient of grating；εεIt is answering for composite
Become；Δ T is the temperature change of composite.
The difference equation of the fitting functions that two of grating centering corresponding grating sensor cell temperatures are demarcated is：
ΔλBT1=kT1ΔT
ΔλBT2=kT2ΔT
Various with reference to more than, composite dependent variable is：
(3) composite Stress calculation
Modulus and strain according to composite, in certain temperature range, can be with direct solution composite stress：
σ=E ε
In formula, σ is composite stress；E is composite modulus.
Case study on implementation 1：
A kind of 360mm × 360mm, [45/0/-45/90]4SCarbon fibre composite slab construction part lightning damage detection dress
Put and method.With optical signal as detection signal, carrier is quartz fibre (glass fibre), diameter to optical fiber Bragg grating sensor
It is very thin, only several times of carbon fiber diameter.Optical fiber Bragg grating sensor is to detect foundation with center wavelength shift, high precision,
Can be not only used for material strain detection, it can also be used to temperature detection, be the ideal transducer of composite lightning damage detection.
Optical fiber Bragg raster is selected in the present embodiment.
Device includes (such as Fig. 1)：Double lead array optical fiber Bragg grating to, fiber coupler, fiber grating digital solution
Adjust instrument (built-in laser), computer etc..
Optical fiber Bragg raster uses double lead structure, and after being subjected to thunderbolt fracture, 1 double lead fiber-optic grating sensor can
To become 2 fiber-optic grating sensors (such as Fig. 2) of single lead, grating can also normal work, it is ensured that lightning stroke process is examined online
The sustainability of survey.
1st, according to structural member size, grating is scribed on 18 optical fiber of 40 μm of cladding diameter, 9 is scribed on every optical fiber
The raster unit of different centre wavelengths, respectively marked as 1-9, each raster unit total length is 40mm, wherein light to raster unit
Grid etching section length 10mm, grid region gradually increase from A ends at intervals of 30mm to B ends raster center wavelength, each centre wavelength
Increment is 4nm.
2nd, the temperature coefficient to every fiber grating is demarcated, and is fitted centre wavelength and temperature relation, obtains grating
Temperature coefficient.
3rd, two fiber gratings are selected to set up grating to (such as Fig. 3), wherein one covers stainless steel tube in raster unit,
And glue is sealed, 18 optical fiber constitute 9 groups of fiber grating pairs, and 1-9 is labeled as to fiber grating pair, and temperature grating marker is T, answers darkening
Grid are labeled as S.
4th, according to [45/0/-45/90]4SPly sequence lays 360mm × 360mm carbon fibre initial rinse fabrics on flat plate mold,
After the laying of sheet material the 16th (90 ° of layings) has been spread, before spreading the 17th laying (90 ° of layings), 9 groups of optical fiber of fiber grating pair
According to 90 ° of directions, equidistantly (40mm) is placed in parallel on prepreg, and optical fiber applies tension force to two ends lead A, B, then spreads
17-32 layers of carbon fibre initial rinse fabric.
5th, optical fiber two ends lead A, B packing protective layer, by composite material preformed body and mould immigration former, presses
According to the technique curing molding for making.The double arrays of 18 fiber gratings composition (temperature matrices T [9 × 9] and strain matrix S [9 ×
9]) formula sensor.
6th, the laminate demoulding after solidification and it is installed on artificial lightning damage test platform, fiber grating A, B two ends
Lead is respectively connected to coupler A, B, and coupler A, B connect grating demodulation instrument by conducting optical fiber, and grating demodulation instrument passes through RJ45
Joint twisted pair line connection computer, there is inspection software in computer, can process fiber grating data, and three-dimensional modeling, and output is aobvious
Show damage profile.
Temperature survey needs to demarcate grating temperature coefficient, and Fig. 4 is for the strain of grating and temperature relation are demarcated and are intended
Close curve.Fig. 5 is the data of grating sensor measurement composite temperature reduction process, and wherein Fig. 5 (a) is a certain raster center
Wavelength change, Fig. 5 (b) is the temperature change after conversion.
Although above-mentioned be described with reference to accompanying drawing to specific embodiment of the invention, not to present invention protection model
The limitation enclosed, one of ordinary skill in the art should be understood that on the basis of technical scheme those skilled in the art are not
Need the various modifications made by paying creative work or deformation still within protection scope of the present invention.
Claims (9)
1. a kind of fibrous composite lightning damage on-line measuring device, it is characterized in that：Including double lead array optical fiber temperature
Grating, double lead array strain fiber grating, two fiber couplers, fiber Bragg grating (FBG) demodulator and processors, wherein：Light source
Laser signal, laser signal is produced to be divided into two-way by conduction optical fiber, the first fiber coupler and the second optical fiber are transferred to respectively
Coupler, the first fiber coupler connection double lead array optical fiber temperature grating and double lead array strain fiber grating
One end lead, the other end lead connection the of double lead array optical fiber temperature grating and double lead array strain fiber grating
Two fiber couplers, form two ports for having laser light incident and reflection concurrently；
The double lead array optical fiber temperature grating, double lead array strain fiber grating are double lead structure, i.e., often
Individual grating has two leads to be connected, and two leads can be as the signalling channel of raster unit, as long as each grating has one
Bars passage just can be used for signal detection；
Double lead array optical fiber temperature grating, all fiber gratings of double lead array strain fiber grating are embedded in advance
Inside composite material structural member, after laser signal interacts with fiber grating, reflection laser passes through two ends lead again respectively
Into first, second fiber coupler, the optical signal of first, second fiber coupler output enters fiber Bragg grating (FBG) demodulator, complete
Into signal demodulation, fiber Bragg grating (FBG) demodulator connection processor, processor is according to signal analysis fibrous composite type of impairment, journey
Degree and its result of distribution.
2. a kind of fibrous composite lightning damage on-line measuring device as claimed in claim 1, it is characterized in that：Described pair is drawn
Line array type optical fiber temperature grating is parallel with double lead array strain fiber grating, arranged adjacent, double lead array temperature
Each strain raster unit that each temperature raster unit in fiber grating strains fiber grating with double lead array is one by one
Correspondence, so that optical fiber temperature constitutes a double lead fiber grating with two corresponding gratings on adjacent strain optical fiber
It is right.
3. a kind of fibrous composite lightning damage on-line measuring device as claimed in claim 1, it is characterized in that：Described pair is drawn
Line array type optical fiber temperature, double lead array strain optical fiber all include that multiple is carved with the raster unit of different centre wavelengths, often
Individual raster unit is an independent sensor unit.
4. a kind of fibrous composite lightning damage on-line measuring device as claimed in claim 1, it is characterized in that：The light source
To be built in the laser in fiber Bragg grating (FBG) demodulator, laser produces continuous frequency modulation laser, and double lead battle array is entered by lead
Column optical fiber temperature grating, double lead array strain fiber grating, form the reflected signal of stabilization.
5. a kind of fibrous composite lightning damage on-line measuring device as claimed in claim 1, it is characterized in that：The treatment
Device, including Geometric Modeling module, fiber grating signal resolution module, damage of composite materials database and lightning damage inverting figure
Interface, wherein, the Geometric Modeling module, for being modeled to composite material structural member, in composite geometrical model
The accurate position for marking raster unit；The fiber grating signal resolution module, passes for analytical calculation fiber Bragg grating (FBG) demodulator
The defeated wavelength signals for coming, obtain temperature, the strain and stress of fiber composite structure part, by itself and damage of composite materials number
Judge type of impairment and degree of injury according to the information contrast stored in storehouse；The lightning damage inverting graphical interfaces, for anti-
Performance composite lightning damage distributed in three dimensions situation is simultaneously exported.
6. a kind of detection method of the device based on as described in claim 1-5, it is characterized in that：Comprise the following steps：
(1) before composite curing molding, the spacing as needed according to setting in structural member lays double lead array
Optical fiber temperature grating, double lead array strain fiber grating；
(2) composite material structural member curing molding, fiber-optic grating sensor is embedded in inside composite material structural member, connection the
One fiber coupler, the second fiber coupler, fiber Bragg grating (FBG) demodulator and processor；
(3) after light source produces laser signal, laser signal to enter the first fiber coupler, the second fiber coupler, pass through respectively
Two ends lead enters double lead array optical fiber temperature grating, double lead array strain fiber grating region, through optical grating reflection
Signal afterwards returns to grating signal (FBG) demodulator through the first fiber coupler, the second fiber coupler, and optical signal is demodulated to numeral
Signal is processed into processor；
(4) 3-D geometric model of composite material structural member is set up by Geometric Modeling module, raster unit numbering by sitting
Mark relationship marking is on the threedimensional model of composite material structural member；The parsing grating signal (FBG) demodulator transmission of grating signal parsing module
The signal for coming, according to the information that double lead array optical fiber temperature grating, double lead array strain fiber grating are gathered, obtains
Composite strain, temperature and STRESS VARIATION；
(5) call composite lightning damage database, identification of damage type and judge degree of injury, obtain raster unit and number
The type of impairment and degree of place composite regional area, type of impairment and degree by stop position data inversion to several
On what model, the dynamic solid distribution map of composite lightning damage is obtained.
7. detection method as claimed in claim 6, it is characterized in that：In the step (1), specific method is：In composite
Before curing molding, the n fiber grating of grating sensor is carved with according to certain spacing laying m as needed in structural member
It is right, optical fiber is marked as 1,2,3, m, raster unit is marked as 1,2,3, n, each grating is to above there is two light
Fine grating, one is the optical fiber temperature grating of measurement temperature, and labeled as T, another is the strain fiber grating of measuring strain, mark
S is designated as, double array optical fiber grating sensors are constituted.
8. detection method as claimed in claim 6, it is characterized in that：In the step (4), when thunderbolt energy is low, fiber grating
Intact, the grating sensor cell signal that two ends lead is collected is identical, and lightning damage detection is carried out using either end signal,
When the energy that is struck by lightning causes damage of composite materials serious and causes fibercuts, double lead fiber grating becomes two single lead light
Fine grating, grating sensor still can be detected and be transmitted signal, and the signal of now two ends lead transmission is intended at detection
Reason, the signal difference transmitted by contrasting two leads determines whether raster unit area damages, and determines the raster unit area of damage
Position, quantity.
9. detection method as claimed in claim 6, it is characterized in that：In the step (5), by measuring raster center wavelength
Drift is realized to measured detection, according to raster center wavelength with stress and the drift relation of temperature, strained and temperature
Information.
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| CN105606275B (en) * | 2015-12-21 | 2018-01-05 | 山东大学 | The core plate on-line monitoring system and method for a kind of membrane filter plate |
| CN105571620B (en) * | 2015-12-21 | 2017-10-03 | 山东大学 | A kind of online damage detection apparatus of filter press filter board and its implementation |
| CN105387890B (en) * | 2015-12-21 | 2017-10-24 | 山东大学 | A kind of barrier film on-line condition monitoring system and method for membrane filter plate |
| US10416103B2 (en) * | 2016-05-02 | 2019-09-17 | The Boeing Company | Thermo-chromatic witness features for lightning strike indication in both metallic and composite structures |
| CN107990926B (en) * | 2017-11-23 | 2019-08-20 | 武汉理工大学 | Fiber grating based on wavelength shift locks demodulating system and method one by one |
| CN107941283B (en) * | 2017-12-22 | 2024-03-12 | 中南大学 | Multi-parameter on-line monitoring system and method for hot-press curing process of composite material |
| CN109060172B (en) * | 2018-09-11 | 2019-04-16 | 山东大学 | Sandwich component lightning damage monitoring device and method based on interplantation fiber grating |
| CN109060205A (en) * | 2018-10-31 | 2018-12-21 | 中船第九设计研究院工程有限公司 | Dock crane stress monitoring system and method based on fiber grating strain induction |
| CN109781777B (en) * | 2018-12-06 | 2020-10-27 | 西安交通大学 | Method and system for measuring and calibrating temperature characteristics of carbon fiber composite material under action of nondestructive lightning current component |
| CN109613005B (en) * | 2018-12-20 | 2022-03-22 | 武汉昊衡科技有限公司 | OFDR-based damage detection method |
| CN109916741B (en) * | 2019-01-18 | 2021-08-13 | 昆明理工大学 | Composite material impact crack detection method based on fiber grating sensing |
| CN113819851B (en) * | 2021-09-18 | 2023-06-09 | 哈尔滨工程大学 | Strain monitoring system of airborne radome based on distributed fiber bragg grating |
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