CN106950280A - Fibre reinforced composites parameter identification method and device based on the lossless scanning of laser - Google Patents
Fibre reinforced composites parameter identification method and device based on the lossless scanning of laser Download PDFInfo
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- CN106950280A CN106950280A CN201710155498.2A CN201710155498A CN106950280A CN 106950280 A CN106950280 A CN 106950280A CN 201710155498 A CN201710155498 A CN 201710155498A CN 106950280 A CN106950280 A CN 106950280A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/04—Analysing solids
- G01N29/045—Analysing solids by imparting shocks to the workpiece and detecting the vibrations or the acoustic waves caused by the shocks
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/36—Detecting the response signal, e.g. electronic circuits specially adapted therefor
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2291/00—Indexing codes associated with group G01N29/00
- G01N2291/02—Indexing codes associated with the analysed material
- G01N2291/023—Solids
- G01N2291/0231—Composite or layered materials
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2291/00—Indexing codes associated with group G01N29/00
- G01N2291/02—Indexing codes associated with the analysed material
- G01N2291/028—Material parameters
Abstract
The present invention discloses a kind of fibre reinforced composites parameter identification method and device based on the lossless scanning of laser, according to fiber-reinforced composite structural material parameter identification method, input first three rank intrinsic frequency, damping ratio and resonance amplitude curve, it is 10% to set identification error permissible value, just can obtain fiber longitudinal modulus of elasticity E1, fiber transverse modulus of elasticity E2, shear modulus G12, Poisson's ratio is ν21And the longitudinal fissipation factor η of fiber11, fiber lateral loss factor η22With shearing fissipation factor η12。
Description
Technical field
The present invention relates to mechanical field, specifically a kind of fibre reinforced composites parameter identification method and device.
Background technology
Structural composite material has designability, heat endurance good because of the specific strength height, specific modulus height, material of its structure,
But also have the advantages that bearing capacity is big, lightweight, it is widely used in Aeronautics and Astronautics, ship, sports apparatus, electrical equipment, doctor
The fields such as, weapon industry and chemical industry.With the continuous improvement of modern industry level, many fiber-reinforced composite thin-walled structures
Part, such as composite material blade, composite blisk and compound organic substrate, its be often operated at a high speed rotation, high temperature,
In the adverse circumstances such as etchant gas erosion, the vibrating fatigue thus brought, vibration failur problem are increasingly protruded, and prevent it from just
Often fulfil function of the people to its advance imagination.
In industrial production using fibre reinforced composites constantly, often require that has to every material property of this kind of material
Clear awareness and understanding.However, due to the anisotropy feature of composite, its fiber longitudinal modulus of elasticity is being detected,
The longitudinal fissipation factor of fiber transverse modulus of elasticity, modulus of shearing, Poisson's ratio and fiber, the fiber lateral loss factor and shearing are damaged
When consuming the material parameters such as the factor, industrially measured mostly by fatigue tester at present.This method has in all many-sides
Its limitation：In terms of cost：Need to destroy more material model, a large amount of wastes are caused in terms of manpower and materials；Measurement means
Aspect：The stretching of high intensity has particular/special requirement to the stability of instrument, while the degree of accuracy of measurement is difficult to ensure that measurement result is deposited
In larger error；Secure context：Material can be broken in measurement process, there is larger hidden danger in safety.
At present, the research to NDT of composite this aspect is not very deep, but has grinding for part correlation yet
Studying carefully has certain reference value.Patent CN201610166104.9 has invented a kind of new composite parameter identifier, leads to
The structure for changing identifier is crossed so that the parameter identified is more accurate, but its principle is still by the biography such as pressing, cutting, draw
System mode measures the parameter of composite, does not solve fundamentally to waste, the problems such as having certain potential safety hazard.Fiber is increased
The detection method of strong composite needs improvement badly, and relevant issues can be solved well using vibration and the lossless scanning technique of laser.
The content of the invention
The problem of existing for prior art, the present invention provides a kind of fiber-reinforced composite knot based on the lossless scanning of laser
Structure material parameter tester and its method of work.Concrete technical scheme is as follows：
Based on the fibre reinforced composites parameter identification method of the lossless scanning of laser, comprise the following steps：
Step 1：Vacuum casting is opened, regulation screws screw rod, composite beam test specimen to be measured is installed on into clamping device successively
Reference position；
Step 2：Screw rod is screwed by regulation, the pressure of clamping device is gradually tightened, the pressure exported according to pressure sensor
Power registration, judgement has been reached after suitable clamping dynamics, stops regulation；
Step 3：Hoistable platform is adjusted to correct position, vacuum casting is tightened；The gas in shell is discharged with air exhauster,
Manufacture vacuum environment；
Step 4：The laser spot position that laser vibration measurer is sent is moved by laser scanning vibration detecting device, is to be measured
The free end position of composite beam test specimen；Then, exciting device is opened, sine sweep exciting survey is carried out in larger frequency range
Examination, the time domain waveform data of scanning frequency excitation signal are monitored according to acceleration transducer in movable vise body, and pass through laser vibration measurer
The frequency spectrum of the vibration response signal of the free end position of composite beam test specimen to be measured is obtained, each peak is recognized by half-power bandwidth method
It is worth corresponding frequency and the frequency of half power points, and then obtains first three rank intrinsic frequency and the damping of composite beam test specimen to be measured
Than；
Step 5：The frequency for adjusting exciting device is first natural frequency, excites survey composite beam test specimen to reach that the first rank is total to
Shake state, the corresponding excitation amplitude of the first rank resonance state is determined by acceleration transducer on shaking platform；Meanwhile, open and swash
The controlling switch of optical scanning vibration detecting device, the laser spot position that laser vibration measurer is sent is moved by laser scanning vibration detecting device,
Realize to composite beam test specimen to be measured from cantilever end position to the sweep test of free end position, obtain composite beam test specimen to be measured every
The vibration response signal amplitude of individual scanning point position, and then draw out composite beam test specimen vibration amplitude under the first rank resonance state
With the change curve with its length, referred to as the first rank resonance amplitude curve, the first rank resonance amplitude curve transverse axis is length
Degree, the longitudinal axis is vibration amplitude；
Step 6：The frequency for adjusting exciting device is second-order intrinsic frequency and the 3rd rank intrinsic frequency, and peace is adopted according to step 5
With the step of, obtain second-order resonance amplitude curve and third order resonance amplitude curve；
Step 7：According to fiber-reinforced composite structural material parameter identification method, first three rank intrinsic frequency, damping ratio are inputted
With resonance amplitude curve, it is 10% to set identification error permissible value, just can obtain fiber longitudinal modulus of elasticity E1, fiber transverse direction bullet
Property modulus E2, shear modulus G12, Poisson's ratio is v21And the longitudinal fissipation factor η of fiber11, fiber lateral loss factor η22With cut
Cut fissipation factor η12。
It is mainly flat by compound workbench, lifting the present invention further discloses a kind of device for realizing methods described
Platform, clamping device, exciting device, laser scanning vibration measuring system and vacuum plant composition；Compound workbench includes the first work
Connected between platform and the second workbench, two platforms by " work " word supporting steel, lower section is supported by base；Clamping device is used to fix
And composite beam test specimen to be measured, including reference platform and its briquetting on top are monitored, the briquetting is pushed by bolt driving, will be to be measured
Composite beam test specimen is fixed；Two borehole structures are provided with reference platform, the round pressure for placement force sensor is sensed
Pad, the amount of constraints is realized according to the numerical value of pressure sensor come quantitative adjustment effect in the pressure of tested composite
Change characterization test；Exciting device is made up of vibrator and shaking platform two parts, and it is to produce exciting force and multiple to being tested that it, which is acted on,
Close the transmission vibration of beam test specimen；Vibrator is connected with signal source, produces the vibration of certain frequency, and vibration passes through shaking platform and clamping
Mechanism passes to beam test specimen to be measured；To realize the monitoring to excited vibration state, acceleration sensing is housed on clamping device top
Device, the size for measuring Oscillation Amplitude；Vibrator, which is bolted, to be fixed on the first workbench, to produce excitation
Power, and apply it on shaking platform；There are four damping for being evenly distributed on corner screw rods, damping spring below excitation platform
It can pack into damping screw rod, realization is connected with the second workbench, and the displacement on axle of spring direction can only be produced between the two；
Laser scanning vibration measuring system includes laser scanning vialog, leading screw, shaft coupling and motor；Carry laser scanning
The platform of vialog is run through by one group of leading screw, and leading screw is connected with shaft coupling, constitutes transmission mechanism；Under the power of motor,
Laser scanning vialog can realize the motion of vibration measurement with laser device horizontal direction by transmission mechanism；What laser vibration measurer was sent
Laser spot position, under certain sweep speed, is realized to composite beam test specimen to be measured from cantilever end position to free end position
Sweep test, obtains vibration response signal amplitude of the composite beam test specimen to be measured in each scanning point position, and then draw out phase
The resonance amplitude curve answered；Laser scanning vibration measuring system, which is arranged on hoistable platform, can be achieved laser scanning vialog in vertical side
The adjustment of upward position, the crane of the rise platform is fixed on the second workbench.
Vacuum plant is provided with the outside of tester, is made up of housing and baffle plate；Baffle plate is closely connected with housing, prevents sky
Gas enters；There is borehole structure on baffle plate, be connected with air pump, so that gas in withdrawing device, creates vacuum environment, reduce experiment
Error.
It is an advantage of the invention that：The invention provides a kind of fiber-reinforced composite structural material based on the lossless scanning of laser
Parameter tester.The parameter test method that vibration transmission is combined with laser displacement sensing technology is devised first, has broken tradition
The pattern measured by physical methods such as stretchings, and realize mechanical property of the disposable measurement detected materials in all directions
The target of energy, considerably reduces the workload of related work；Secondly, instrument will not be produced in the whole process of test to material
Any influence, has saved raw material, reduces economic loss, more environmental protection；In addition, outside installs setting for vaccum case additional
Meter so that test process is carried out under vacuo, it is to avoid the influence of air damping, measurement result is more accurate；Finally, this work
Product are easy to assembly and disassembly, and the quality of each part is little, can load drawing case, with preferable portability.Can be according to reality
Situation measures the parameter of composite in different location, is provided a great convenience for production measurement.
Brief description of the drawings
Fig. 1 is the front view of the fiber-reinforced composite structural material parameter tester of the specific embodiment of the invention；
Fig. 2 is the top view of the fiber-reinforced composite structural material parameter tester of the specific embodiment of the invention；
Fig. 3 is the structure letter of the fiber-reinforced composite structural material parameter tester of the specific embodiment of the invention；
Fig. 4 is the theoretical model of fiber-reinforced composite beam test specimen under Fig. 1 basic excitations；
Fig. 5 is theoretical and experiment obtains composite beam the first rank resonance amplitude curve and its error bound figure；
In figure：1- bases, the workbenches of 2- second, 3- " work " word supporting steel, the workbenches of 4- first, 5- shaking platforms,
6- damping springs, 7- baffle plates, 8- clamping devices, 9- acceleration transducers, 10- leading screws, 11- laser scanning vialogs, 12- shells
Body, 13- sliding blocks, 14- hoistable platforms, 15- beam test specimens to be measured, 16- vibrators, 17- shaft couplings, 18- motor, 19- is scalable
Platform, 20- steam vents, 21- reference platforms.
Embodiment
The present invention is illustrated below in conjunction with the accompanying drawings.
1. tester Design of Hardware Architecture
As illustrated, the present invention device mainly by compound workbench, hoistable platform, clamping device, exciting device,
Laser scanning vibration measuring system and vacuum plant composition；
Compound workbench is included between the first workbench 4 and the second workbench 2, two platforms by " work " word supporting steel 3
Connection, lower section is supported by base 1；Clamping device 8 is used to fixing and monitoring composite beam test specimen 15 to be measured, including reference platform 17 and
The briquetting 18 on its top, the briquetting is pushed by bolt driving, and composite beam test specimen to be measured is fixed；
The upper surface of reference platform 17 is provided with two borehole structures, the round pressure sensor mat for placement force sensor
Piece, the quantization of constraints is realized according to the numerical value of pressure sensor come quantitative adjustment effect in the pressure of tested composite
Characterization test.
Exciting device is made up of vibrator 16 and the two parts of shaking platform 5, and it is to produce exciting force and multiple to being tested that it, which is acted on,
Close the transmission vibration of beam test specimen；Vibrator is connected with signal source, produces the vibration of certain frequency, and vibration passes through shaking platform 5 and folder
Hold mechanism 8 and pass to beam test specimen 15 to be measured；To realize the monitoring to excited vibration state, on the top of clamping device 8 equipped with acceleration
Spend sensor 9, the size for measuring Oscillation Amplitude.Vibrator 16, which is bolted, to be fixed on the first workbench 4, is used
To produce exciting force, and apply it on shaking platform 5；There are four dampings for being evenly distributed on corner the lower section of excitation platform 5
Screw rod, damping spring 6 can be packed into damping screw rod, and realization is connected with the second workbench 2, and spring shaft can only be produced between the two
Displacement on line direction.
Laser scanning vibration measuring system includes laser scanning vialog 11, leading screw 10, shaft coupling and motor.Carry laser
The platform of scanning vialog is run through by one group of leading screw, and leading screw is connected with shaft coupling, constitutes transmission mechanism；In the power of motor
Under, laser scanning vialog can realize the motion of vibration measurement with laser device horizontal direction by transmission mechanism.Laser vibration measurer is sent out
The laser spot position gone out, under certain sweep speed, realization position from cantilever end position to free end to composite beam test specimen to be measured
The sweep test put, obtains vibration response signal amplitude of the composite beam test specimen to be measured in each scanning point position, and then draw
Go out corresponding resonance amplitude curve.Laser scanning vibration measuring system is arranged on hoistable platform 14 achievable laser scanning vialog and existed
The adjustment of position on vertical direction, the crane of the rise platform 14 is fixed on the second workbench 2, two cross-articulations
Support beam, one is fixed on workbench 2, and one connects with the axle of sliding block 13 in addition, and sliding block passes through leading screw and motor connection；
Under motor driving, leading screw band movable slider 13 slides on workbench and then drives hoistable platform to move up and down；
Vacuum plant is provided with the outside of tester, is made up of housing and baffle plate.Baffle plate can be closely connected with housing, be prevented
Air enters；There is borehole structure on baffle plate, can be connected with air pump, so that gas in withdrawing device, creates vacuum environment, reduce
Experimental error.
2. described in fiber-reinforced composite structural material parameter identification method be：
Vibratory response is solved under 2.1 fiber-reinforced composite beam test specimen inherent characteristics and basic excitation；
Composite beam test specimen is the fiber and matrix material combinations for having orthotropy feature by n-layer；Assuming that
It is secure bond between each layer, interlayer is without sliding, no relative displacement, admittedly the influence of proximity effects can not be considered；It is first
First, wherein as a reference plane, and xoy coordinate systems will be set up in face；Assuming that machine direction and the angle in global coordinate system x-axis direction
For θ, a length of a of plate, a width of b of plate, thickness of slab is h, and each layer is located at the relatively low surface h of z coordinate axlek-1With high surfaces hkBetween, every layer
Thickness all same；1 in figure represents fiber longitudinal direction, and 2 represent fiber transverse direction, and 3 represent perpendicular to the direction of 1-2 planes；
Assuming that composite beam test specimen is influenceed by basic excitation load, and the motion expression formula of the basic excitation for y (t)=
Yeiωt (1)
I represents empty unit
T represents the time
Wherein, Y is excitation amplitude, and ω is driving frequency；
Consider the influence of machine direction, the elastic modelling quantity of composite is expressed as form
Wherein,The complex modulus in parallel fibers direction and vertical fibers direction is represented respectively,1-2 is represented to put down
Complex shear modulus in face, E '1、E′2With G '12Difference complex modulus And complex shear modulusReal part；And 1 side
The Poisson's ratio for causing 1,2 directions to strain to applied stress is v12, 2 direction applied stresses cause 1,2 directions strain Poisson's ratio be
v21；
The Poisson's ratio of direction strain is v21；
Based on Classical lamination theory, the displacement field of fiber-reinforced composite beam test specimen can be written as following form
Wherein, z represents displacement in the z-axis direction；U, v, w represent the displacement at any point in plate；u0,v0,w0Represent plate
Middle face displacement；H is the thickness of composite beam test specimen；T represents the time；
Due to being Analysis of Symmetric Laminated Plates, coupling is not present in plane vibration and oscillation crosswise, therefore need to only consider the transverse direction of thin plate
Vibration, that is, ignore middle face displacement components u0And v0；It can be seen from the hypothesis of Classical lamination theory, normal strain εzWith shearing strain γyz、
γxzAll it is 0, i.e. εz=γyz=γxz=0, it can be expressed as by the strain for straining any point in the relation with displacement, plate
εxRepresent the normal strain of point in the x direction
εyRepresent the normal strain of point in y-direction
εxyRepresent shearing strain of this on x/y plane
Face bending deflection rate and twisting coefficient are represented by thin plate
kxRepresent the deflection rate of point in the x direction
kyRepresent the deflection rate of point in y-direction
kxyRepresent twisting coefficient of this on x/y plane
I.e.
εx=z κx, εy=z κy, γxy=z κxy
For orthotropic material, the strain-stress relation of material major axes orientation is
1 represents fiber longitudinal direction, and 2 represent that fiber is horizontal, and 6 represent vertical plate face direction, and Q* represents coefficient of elasticity
Wherein,
When having certain angle theta between material major axes orientation and global coordinate system, calculated with stress-strain rotation axis formula
It is as follows to strain-stress relation of the kth laminate under global coordinate system
Wherein,
Wherein, k represents the kth layer of composite beam test specimen, θkRepresent the machine direction and global coordinate system x-axis of kth laminate
Angle；
Thin plate institute's bending moment and moment of torsion are
MxRepresent the moment of flexure on x-axis direction
MyRepresent the moment of flexure on y-axis direction
MxyRepresent the moment of torsion on x/y plane
D* represents bending stiffness coefficient
Wherein,
Modeled for the ease of theory analysis, basic excitation suffered by composite beam test specimen is equivalent to carry outside uniform inertia force
Y represents the displacement amplitude of basic excitation
Then the kinetic energy of thin plate vibration can be represented with following formula
Wherein, ρ is the density of thin plate, and h is gauge of sheet；
Then the strain energy of thin plate bending storage is represented with following formula
Uniform inertia force suffered by thin plate, which does work, is
Wq=∫ ∫Rq(t)w0dxdy (13)
Assuming that the vibration displacement of thin plate oscillation crosswise can be expressed as
w0(x, y, t)=eiωtW(ξ,η) (14)
Wherein, ω is the circular frequency of thin plate vibration, W identical with driving frequencyij(ξ, η) is model function of vibration, there is following form
Wherein, aijFor undetermined coefficient, pi(ξ) (i=1 ..., M) and qj(η) (j=1 ..., N) it is a series of orthogonal
Multinomial；
A series of orthogonal polynomial is obtained by being orthogonalized processing to the polynomial function for meeting boundary condition
P1(ξ)=χ (ξ), P1(η)=κ (η)
P2(ζ)=(ζ-B2)P1(ζ)
Pk(ζ)=(ζ-Bk)Pk-1(ζ)-CkPk-2(ζ)
ζ=ξ, η, k>2 (16)
Wherein, BkAnd CkFor coefficient function, its expression formula is respectively
Wherein, W (ζ) is weight function, generally takes W (ζ)=1；And χ (ξ) and κ (η) be meet clamped, freely-supported, freely it is equilateral
The polynomial function of boundary's condition, and with following form
χ (ξ)=ξp(1-ξ)q, κ (η)=ηr(1-η)s
ξ=x/a, η=y/b (18)
Due to being cantilever, so p=2 is taken, r=0, q=0, s=0；By formula (15) substitute into formula (11),
(12) and in (13), the maximum kinetic energy T of composite beam test specimen vibration can be obtainedmax, maximum strain energy UmaxDone with uniform inertia force
Work(maximum WqmaxRespectively
Wqmax=ρ hY ω2∫∫RWdxdy (21)
The Lagrangian energy function L of definition expression formula is
L=Tmax+Wqmax-Umax (22)
By making energy function L to undetermined coefficient aijPartial derivative be equal to zero, i.e.,
M × N number of Nonhomogeneous Linear algebraic equation can be obtained, in order to solve conveniently, being written as matrix form is
(K+iC-ω2M) a=F (24)
Wherein, K, C and M are respectively structural stiffness matrix, material damping matrix and architecture quality matrix, generalized displacement vector
A=(a11,a12,…aij)T, F is exciting force vector；
For the vibration problems of composite beam test specimen, it is zero that only need to make material damping Matrix C and exciting force vector F, i.e.,
(K-ω2M) a=0 (25)
The intrinsic frequency and Mode Shape of composite beam test specimen can be tried to achieve by formula (25)；Further, it is assumed that fiber reinforcement is multiple
Close beam test specimen to be acted on by basic excitation load, and solve the expression formula of its vibratory response λ (x, y, t) under basic excitation；Consider
What it is to experiment test acquisition is the response of composite beam test specimen absolute vibration, i.e., vibratory response and basic excitation displacement including its own
Sum；Therefore, the vibratory response λ (x, y, t) of composite beam test specimen under basic excitation can be expressed as
λ (x, y, t)=y (t)+w0(x,y,t) (26)
Formula (26) is the solution expression formula for giving fiber-reinforced composite beam test specimen vibratory response under basic excitation, clear and definite
In the case of basic excitation expression formula (1) and thin plate vibration response expression formula (14), acquisition composite beam test specimen can be calculated any
The vibratory response of a bit；
2.2 obtain composite parameter based on first three rank intrinsic frequency and damping test result primary Calculation
First, the material parameter average provided with manufacturerCentered on, it is considered to Rerr=10%~20% misses
Difference, the span for providing material parameter is as follows
Suitable step-length building material parameter vector E is chosen in each value range of material parameters1,E2,G12,ν12, specifically
Expression formula is
On the basis of the theoretical intrinsic frequency with experiment is obtained respectively, relative difference on frequency letter is constructed based on least square method
Number efre：
Wherein, R is rank number of mode, Δ fiConsolidate for theoretical calculation the i-th rank intrinsic frequency obtained and the i-th rank that experiment is obtained
There is frequency-splitting,The the i-th rank intrinsic frequency obtained for experiment test；
Material parameter is iterated in the way of permutation and combination, as least square relative error function efreObtain minimum
During value, i.e., primary Calculation obtains material parameter E1,E2,G12,v12；
Then, each rank modal loss factor η can be obtained by the relation of damping ratio and fissipation factorrFor
ηr=2 ζr (30)
Wherein, ζrThe damping ratios obtained for experiment；
According to modal strain energy method, the strain energy U of fiber longitudinal direction, fiber transverse direction and shear direction1、U2And U12Respectively
The fissipation factor of modal loss factor and fiber all directions has following relation
Wherein, U is the total strain energy of composite beam test specimen；
From formula (32), as long as obtaining 3 rank damping ratios results before composite beam test specimen by testing, it is possible to preliminary
Determine the fissipation factor η of fiber longitudinal direction, fiber transverse direction and shear direction1、η2And η12；
Thus, just E can be obtained by first three rank intrinsic frequency and damping test result, primary Calculation1,E2,G12,v12η1、η2
And η12Deng 7 material parameters；
2.3 based on the lossless scanning experimental data accurate recognition composite parameter of laser
First, first three rank intrinsic frequency and damping ratio of composite beam test specimen are obtained by experiment test, and with above-mentioned intrinsic
Frequency excites composite beam test specimen to reach resonance state, then obtains first three rank of composite beam respectively by the lossless scanning experiment of laser
Resonance amplitude curve；Then, fiber longitudinal modulus of elasticity E is being primarily determined that1, fiber transverse modulus of elasticity E2, shear modulus G12、
Poisson's ratio v12, the longitudinal fissipation factor η of fiber1, fiber lateral loss factor η2With shearing fissipation factor η12On the basis of, it is considered to more
Small error range (such as 10%), with smaller step-length building material parameter vector, and to parameter in the way of permutation and combination
It is iterated, per iteration once, the corresponding resonance amplitude curve of one group of first three rank intrinsic frequency just can be obtained by theoretical calculation；
Finally, the corresponding resonance amplitude curve of first three rank intrinsic frequency and test for contrasting the acquisition of certain theoretical calculation are obtained
First three rank resonance amplitude curve deviation；Exemplified by contrasting the first rank resonance amplitude curve, the curve obtained when theoretical calculation
When in error bound curve ranges, you can it is material parameter that is accurate, now being used to think above-mentioned material parameter
As recognize the final material parameter of acquisition.
Identification flow includes：
(1) inherent characteristic and vibratory response to fiber-reinforced composite beam test specimen are solved
First, the theoretical model of fiber-reinforced composite beam test specimen is established based on Classical lamination theory, and by its material
Parameter is expressed as the form of complex modulus；Then, inherent characteristic and the basis of composite beam test specimen have been solved based on Ritz energy methods
The vibratory response of the lower composite beam test specimen of excitation；
(2) test obtains first three rank intrinsic frequency and damping ratio of composite beam test specimen
The laser spot position that laser vibration measurer is sent is moved by laser scanning vibration detecting device, composite beam to be measured is at
The free end position of test specimen；Then, exciting device is opened, sine sweep exciting test is carried out in larger frequency range, according to
Acceleration transducer monitors the time domain waveform data of scanning frequency excitation signal on shaking platform, and is obtained by the test of laser vibration measurer part
The frequency spectrum of the vibration response signal of the free end position of composite beam test specimen to be measured is obtained, each peak value is recognized by half-power bandwidth method
The frequency of corresponding frequency and half power points, and then obtain first three rank intrinsic frequency and damping ratio of composite beam test specimen to be measured；
(3) primary Calculation composite parameter
Centered on the material parameter average provided first by manufacturer, building material parameter vector, in the way of permutation and combination
Material parameter is iterated, when the phase for the i-th rank intrinsic frequency that the i-th rank intrinsic frequency that theoretical calculation is obtained is obtained with experiment
, just can primary Calculation acquisition fiber longitudinal modulus of elasticity E when taking minimum value to error function1, fiber transverse modulus of elasticity E2, cut
Shear modulu G12With Poisson's ratio v12；Then, based on modal strain energy method, 3 rank modal losses before composite beam test specimen are obtained by testing
Factor outcomes, primary Calculation fiber longitudinal direction fissipation factor η1, fiber lateral loss factor η2With shearing fissipation factor η12；
(4) tested by the lossless scanning of laser, accurate test obtains first three rank resonance amplitude curve of composite beam, regulation swashs
The frequency of vibrating device is first natural frequency, excites survey composite beam test specimen to reach the first rank resonance state, passes through shaking platform
Upper acceleration transducer determines the corresponding excitation amplitude of the first rank resonance state；Meanwhile, open the control of laser scanning vibration detecting device
System switch, the laser spot position that laser vibration measurer is sent is moved by laser scanning vibration detecting device, under certain sweep speed,
Realize to composite beam test specimen to be measured from cantilever end position to the sweep test of free end position, obtain composite beam test specimen to be measured every
The vibration response signal amplitude of individual scanning point position, and then draw out the first rank resonance amplitude curve；The step is repeated, can be according to
Secondary acquisition second-order resonance amplitude curve and third order resonance amplitude curve；
(5) accurate identification composite parameter
Centered on the material parameter tentatively obtained in step 3, it is considered to smaller error range (such as 10%), with smaller
Step-length building material parameter vector, and parameter is iterated in the way of permutation and combination, per iteration once, just can pass through reason
The corresponding resonance amplitude curve of one group of first three rank intrinsic frequency is obtained by calculating；Then, contrast before the acquisition of certain theoretical calculation
The deviation for first three rank resonance amplitude curve that the corresponding resonance amplitude curve of three rank intrinsic frequencies and test are obtained；Work as theoretical calculation
When the curve of acquisition is located in error bound curve ranges, you can it is accurate to think above-mentioned material parameter, is now used
Material parameter be identification obtain final material parameter.
Claims (3)
1. the fibre reinforced composites parameter identification method based on the lossless scanning of laser, it is characterised in that comprise the following steps：
Step 1：Vacuum casting is opened, regulation screws screw rod, composite beam test specimen to be measured is installed on to the benchmark of clamping device successively
Position；
Step 2：Screw rod is screwed by regulation, the pressure of clamping device is gradually tightened, the pressure exported according to pressure sensor shows
Number, judgement has been reached after suitable clamping dynamics, stops regulation；
Step 3：Hoistable platform is adjusted to correct position, vacuum casting is tightened；The gas in shell is discharged with air exhauster, manufacture
Vacuum environment；
Step 4：The laser spot position that laser vibration measurer is sent is moved by laser scanning vibration detecting device, is to be measured compound
The free end position of beam test specimen；Then, exciting device is opened, sine sweep exciting test, root are carried out in larger frequency range
The time domain waveform data of scanning frequency excitation signal are monitored according to acceleration transducer in movable vise body, and are treated by laser vibration measurer
The frequency spectrum of the vibration response signal of the free end position of composite beam test specimen is surveyed, each peak value correspondence is recognized by half-power bandwidth method
Frequency and half power points frequency, and then obtain first three rank intrinsic frequency and damping ratio of composite beam test specimen to be measured；
Step 5：The frequency for adjusting exciting device is first natural frequency, excites survey composite beam test specimen to reach first order resonant shape
State, the corresponding excitation amplitude of the first rank resonance state is determined by acceleration transducer on shaking platform；Meanwhile, open laser and sweep
The controlling switch of vibration detecting device is retouched, the laser spot position that laser vibration measurer is sent is moved by laser scanning vibration detecting device, is realized
To composite beam test specimen to be measured from cantilever end position to the sweep test of free end position, obtain composite beam test specimen to be measured and swept each
Retouch the vibration response signal amplitude of point position, so draw out under the first rank resonance state composite beam test specimen vibration amplitude with
The change curve of its length, referred to as the first rank resonance amplitude curve, the first rank resonance amplitude curve transverse axis are length, are indulged
Axle is vibration amplitude；
Step 6：The frequency for adjusting exciting device is second-order intrinsic frequency and the 3rd rank intrinsic frequency, and peace is used according to step 5
Step, obtains second-order resonance amplitude curve and third order resonance amplitude curve；
Step 7：According to fiber-reinforced composite structural material parameter identification method, input first three rank intrinsic frequency, damping ratio and be total to
Shake amplitude curve, and it is 10% to set identification error permissible value, just can obtain fiber longitudinal modulus of elasticity E1, fiber transverse elasticity mould
Measure E2, shear modulus G12, Poisson's ratio is ν21And the longitudinal fissipation factor η of fiber11, fiber lateral loss factor η22Damaged with shearing
Consume factor η12。
2. a kind of device for realizing claim 1 methods described, it is characterised in that：It is mainly flat by compound workbench, lifting
Platform, clamping device, exciting device, laser scanning vibration measuring system and vacuum plant composition；Compound workbench includes the first work
Connected between platform and the second workbench, two platforms by " work " word supporting steel, lower section is supported by base；Clamping device is used to fix
And composite beam test specimen to be measured, including reference platform and its briquetting on top are monitored, the briquetting is pushed by bolt driving, will be to be measured
Composite beam test specimen is fixed；Two borehole structures are provided with reference platform, the round pressure for placement force sensor is sensed
Pad, the amount of constraints is realized according to the numerical value of pressure sensor come quantitative adjustment effect in the pressure of tested composite
Change characterization test；Exciting device is made up of vibrator and shaking platform two parts, and it is to produce exciting force and multiple to being tested that it, which is acted on,
Close the transmission vibration of beam test specimen；Vibrator is connected with signal source, produces the vibration of certain frequency, and vibration passes through shaking platform and clamping
Mechanism passes to beam test specimen to be measured；To realize the monitoring to excited vibration state, acceleration sensing is housed on clamping device top
Device, the size for measuring Oscillation Amplitude；Vibrator, which is bolted, to be fixed on the first workbench, to produce excitation
Power, and apply it on shaking platform；There are four damping for being evenly distributed on corner screw rods, damping spring below excitation platform
It can pack into damping screw rod, realization is connected with the second workbench, and the displacement on axle of spring direction can only be produced between the two；
Laser scanning vibration measuring system includes laser scanning vialog, leading screw, shaft coupling and motor；Carry laser scanning vibration measuring
The platform of instrument is run through by one group of leading screw, and leading screw is connected with shaft coupling, constitutes transmission mechanism；Under the power of motor, laser
Scanning vialog can realize the motion of vibration measurement with laser device horizontal direction by transmission mechanism；The laser that laser vibration measurer is sent
Point position, under certain sweep speed, is realized to composite beam test specimen to be measured from cantilever end position to the scanning of free end position
Test, obtains vibration response signal amplitude of the composite beam test specimen to be measured in each scanning point position, and then draw out corresponding
Resonance amplitude curve；Laser scanning vibration measuring system, which is arranged on hoistable platform, can be achieved laser scanning vialog in the vertical direction
The adjustment of position, the crane of the rise platform is fixed on the second workbench.
3. device according to claim 1, it is characterised in that：Be provided with vacuum plant in the outside of tester, by housing and
Baffle plate is constituted；Baffle plate is closely connected with housing, prevents that air from entering；There is borehole structure on baffle plate, be connected with air pump, so as to take out
Go out gas in device, create vacuum environment, reduce experimental error.
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| PCT/CN2017/078513 WO2018165999A1 (en) | 2017-03-16 | 2017-03-29 | Fiber reinforced composite material parameter identifying method based on laser nondestructive scanning, and device |
| JP2019548923A JP7109798B2 (en) | 2017-03-16 | 2017-03-29 | Method and Apparatus for Nondestructive Laser Scanning Fiber Reinforced Composite Parameter Identification |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102538950A (en) * | 2010-12-23 | 2012-07-04 | 沈阳黎明航空发动机(集团)有限责任公司 | Acoustic testing method for inherent frequency of engine part |
| CN103528782A (en) * | 2013-10-23 | 2014-01-22 | 东北大学 | Thin-walled structure part vibration test device and method based on piezoelectric ceramic vibration exciter |
| CN105628496A (en) * | 2016-03-22 | 2016-06-01 | 北京航空航天大学 | Multifunctional shearing test fixture used for composite material parameter identification |
Family Cites Families (19)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0785047B2 (en) * | 1987-04-06 | 1995-09-13 | 大阪府 | Measuring method and measuring device for loss coefficient, dynamic elastic coefficient, dynamic shear elastic coefficient and dynamic Poisson's ratio of rod or plate |
| US5086775A (en) * | 1990-11-02 | 1992-02-11 | University Of Rochester | Method and apparatus for using Doppler modulation parameters for estimation of vibration amplitude |
| JPH05302880A (en) * | 1992-04-28 | 1993-11-16 | Ishikawajima Harima Heavy Ind Co Ltd | Apparatus for fatigue test |
| JPH063237A (en) * | 1992-06-24 | 1994-01-11 | Fujitsu Ltd | Measuring device for young's modulus and measuring method for young's modulus |
| US5533399A (en) * | 1992-09-30 | 1996-07-09 | Wayne State University | Method and apparatus for non-destructive measurement of elastic properties of structural materials |
| JP3308667B2 (en) * | 1993-07-16 | 2002-07-29 | 東芝タンガロイ株式会社 | Ultrasonic vibration type fatigue tester |
| JP3785785B2 (en) * | 1998-02-04 | 2006-06-14 | ソニー株式会社 | Material property measuring device |
| JP3374973B2 (en) * | 2000-11-10 | 2003-02-10 | 独立行政法人産業技術総合研究所 | Measuring method and measuring device for output pressure of constant section working body |
| US7798000B1 (en) * | 2005-10-28 | 2010-09-21 | Trustees Of Boston University | Non-destructive imaging, characterization or measurement of thin items using laser-generated lamb waves |
| DE102006013770A1 (en) | 2006-03-24 | 2007-09-27 | Occlutech Gmbh | Occlusion instrument and method for its production |
| FR2949153B1 (en) * | 2009-08-11 | 2014-11-21 | Centre Nat Rech Scient | METHOD FOR DETERMINING A PHYSICAL PARAMETER, IMAGING METHOD AND DEVICE FOR CARRYING OUT SAID METHOD. |
| JP2013203788A (en) * | 2012-03-27 | 2013-10-07 | Teijin Ltd | Vibration-damping structure |
| JP6079776B2 (en) * | 2012-06-06 | 2017-02-15 | 日本電気株式会社 | Structure analyzing apparatus and structure analyzing method |
| CN103713048A (en) * | 2013-12-10 | 2014-04-09 | 同济大学 | Ultrasonic field non-contact visualization method for nondestructive inspection and device thereof |
| CN110867469B (en) | 2014-03-17 | 2023-12-29 | 三星显示有限公司 | Organic EL display device |
| CN103940685A (en) * | 2014-04-25 | 2014-07-23 | 华侨大学 | Method for testing high-frequency fatigue characteristic of material under microscale |
| JP6413596B2 (en) * | 2014-10-10 | 2018-10-31 | 横河電機株式会社 | Resonance frequency measurement system, resonance frequency measurement method |
| CN104897268B (en) * | 2015-06-08 | 2017-12-29 | 东北大学 | High-grade, digitally controlled machine tools Mode Shape test device and method based on laser scanning |
| CN105510435A (en) * | 2015-11-27 | 2016-04-20 | 航天晨光股份有限公司 | Method for detecting defects of metal bellows based on laser vibration |
-
2017
- 2017-03-16 CN CN201710155498.2A patent/CN106950280B/en active Active
- 2017-03-29 JP JP2019548923A patent/JP7109798B2/en active Active
- 2017-03-29 WO PCT/CN2017/078513 patent/WO2018165999A1/en active Application Filing
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102538950A (en) * | 2010-12-23 | 2012-07-04 | 沈阳黎明航空发动机(集团)有限责任公司 | Acoustic testing method for inherent frequency of engine part |
| CN103528782A (en) * | 2013-10-23 | 2014-01-22 | 东北大学 | Thin-walled structure part vibration test device and method based on piezoelectric ceramic vibration exciter |
| CN105628496A (en) * | 2016-03-22 | 2016-06-01 | 北京航空航天大学 | Multifunctional shearing test fixture used for composite material parameter identification |
Non-Patent Citations (3)
| Title |
|---|
| A.A.EREMIN等: "Evaluation of effective elastic properties of layered composite fiber-reinforced plastic plates by piezoelectrically induced guided waves and laser Doppler vibrometry", 《COMPOSITE STRUCTURES》 * |
| 徐炜等: "用激光扫描测振仪测定石膏悬臂梁动弹性模量", 《河海大学学报（自然科学版）》 * |
| 薛鹏程等: "悬臂边界下纤维增强复合薄板固有频率计算机验证", 《航空动力学报》 * |
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|---|---|---|---|---|
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| JP7109798B2 (en) | 2022-08-01 |
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