CN107818222A

CN107818222A - Heat is shaken fiber composite plate nonlinear kinetics parameter test method and system under environment

Info

Publication number: CN107818222A
Application number: CN201711057508.5A
Authority: CN
Inventors: 李晖; 许卓; 常永乐; 胡明宇; 吴怀帅; 闻邦椿
Original assignee: Northeastern University China
Current assignee: Northeastern University China
Priority date: 2017-11-01
Filing date: 2017-11-01
Publication date: 2018-03-20

Abstract

A kind of heat of the present invention is shaken fiber composite plate nonlinear kinetics parameter test method and system under environment, including：Heat is built to shake test environment, fiber composite plate is fixed on the mounting platform of vibration module by installs fixture, mounting platform is stretched into the heat insulating box of thermal environment simulation module and by soft adhesive tape sealing, laser scanning vibration measuring module is arranged above heat insulating box, the high temperature resistance optical glass of laser through heat insulating box top surface is scanned fiber composite plate during test；Each rank nonlinear natural frequency, each rank nonlinear analog-circuit vibration shape and nonlinear dampling of the composite plate under different excitation amplitudes under the hot environment that shakes of test successively.The present invention provides a kind of complete and effective method of testing and system, can accurately obtain the nonlinear kinetics parameter including nonlinear natural frequency, the nonlinear analog-circuit vibration shape and nonlinear dampling.

Description

Heat is shaken fiber composite plate nonlinear kinetics parameter test method and system under environment

Technical field

The invention belongs to vibration test technology field, specifically a kind of heat is shaken fiber composite plate nonlinear kinetics under environment Parameter test method and system.

Background technology

The specific strength of fibre reinforced composites and its structure is high, specific modulus is high, material has designability, heat endurance It is good, but also have the advantages that bearing capacity is big, in light weight, it is widely used in Aeronautics and Astronautics, auto industry, ship, sports apparatus With the key areas such as weapon industry.At present, engineering exists largely by composite plate structure part made of the type material in practice, The heat that they are generally in hundreds of degrees Celsius or even thousands of degrees Celsius is shaken under environment, such as hypersonic aircraft, aero-engine With gas turbine blades etc..In thermal force and the collective effect of dynamic load, composite and its macroscopic view knot will be not only influenceed The mechanical characteristic of component, change the modulus of elasticity of material, so as to reduce the bearing capacity of structure and strength degree, and can shadow Ring the rigidity and damping characteristic of structure.Therefore, research heat shake the dependent dynamics problem of composite plate structure under environment have it is important Engineering and academic significance.

Because fibre reinforced composites show obvious anisotropy feature, cause material that there is nonlinear structure Relation.Meanwhile its macrostructure also shows (to be referred to as frequency to rely on extraneous exciting amplitude and the damping characteristic of frequency change Property and amplitude dependencies) and nonlinear rigidity characteristic (intrinsic frequency changes also with amplitude), this is to traditional with line Property it is equivalent based on dynamic analysis and method of testing carry out very big challenge, up to the present, academic and engineering circles shake for heat Fiber composite plate nonlinear kinetics parameter testing problem under environment, a kind of complete and effective method of testing is not yet established, Lack special test system accurately to obtain including nonlinear natural frequency, the nonlinear analog-circuit vibration shape and nonlinear dampling Nonlinear kinetics parameter.

The content of the invention

The present invention provides a kind of heat and shaken fiber composite plate nonlinear kinetics parameter test method and system under environment, can be with Accurately obtain the nonlinear kinetics parameter including nonlinear natural frequency, the nonlinear analog-circuit vibration shape and nonlinear dampling.

The present invention provides a kind of heat and shaken fiber composite plate nonlinear kinetics parameter test method under environment, including following step Suddenly：

Step 1：Build heat to shake test environment, the installation that fiber composite plate is fixed on to vibration module by installs fixture is put down On platform, mounting platform is stretched into the heat insulating box of thermal environment simulation module and by soft adhesive tape sealing, by laser scanning vibration measuring Module is arranged above heat insulating box, makes laser through the high temperature resistance optical glass of heat insulating box top surface to fiber composite during test Plate is scanned；

Step 2：Test temperature is set by thermal environment simulation module, to be tested each rank intrinsic frequency of composite plate as sharp Encourage frequency and sweep check is carried out respectively under certain excitation amplitude to composite plate, shaken with obtaining composite plate in the heat of different temperatures The response curve of each rank nonlinear natural frequency under environment；

Step 3：Test temperature is set by thermal environment simulation module, each rank that the heat obtained using test is shaken under environment is non- Linear intrinsic frequency, composite plate is carried out by vibration module and determines frequency resonance excitation, and then excite it to reach resonance state, then profit The multirow or multiple row of composite plate are evenly scanned with laser spots, to obtain the often vibratory response data of row or each column, and from vibration The vibration shape is identified in response data and draws Mode Shape, it is non-thread in each rank that the heat of different temperatures is shaken under environment to obtain composite plate Property solid Mode Shape；

Step 4：Test temperature is set by thermal environment simulation module, it is non-linear solid using what is obtained in step 2 and step 3 Have the result of frequency and Mode Shape, it is determined that during test response point position, and test compound plate shakes ring in the heat of different temperatures Each rank nonlinear dampling under border.

The present invention also provides a kind of heat and shaken fiber composite plate nonlinear kinetics parameter test system under environment, including：

Enter the vibration module of row energization to composite plate using each rank intrinsic frequency of fiber composite plate as driving frequency, be used for Composite plate is scanned to obtain the laser scanning vibration measuring module of vibratory response data, to vibratory response data Reason is to test the Data Management Analysis module of nonlinear kinetics parameter, for controlling test environment temperature according to test request Thermal environment simulation module；

The thermal environment simulation module includes：Using heat insulating box made of high-temperature resistant thermal insulating material, the heat insulating box Top surface and front be provided with use observation window made of high temperature resistance optical glass, carbon fiber heating tube is installed in heat insulating box, every Both sides are provided with fan in hot tank body, and heat insulating box inner upper corner is respectively equipped with thermocouple, heat insulating box bottom opening, led to Screw is crossed with heat insulation pedestal to be connected；

The fiber composite plate is fixed on by installs fixture on the mounting platform of the vibration module, the mounting platform Stretched into by the heat insulating box bottom opening inside the heat insulating box, mounting platform and heat insulation pedestal are realized by flexible glue bar It is tightly connected；

The laser scanning vibration measuring module is arranged on the top of the heat insulating box, and the laser is through described anti-during test High Temperature Optical glass is scanned to the fiber composite plate.

The heat of the present invention is shaken fiber composite plate nonlinear kinetics parameter test method and system under environment, can accurately be obtained Take the nonlinear kinetics parameter including nonlinear natural frequency, the nonlinear analog-circuit vibration shape and nonlinear dampling.And according to Test request changes the temperature in heat insulating box to realize the nonlinear kinetics parameter testing under normal temperature environment and isoperibol.

Brief description of the drawings

Fig. 1 is that the heat of the present invention is shaken the flow chart of fiber composite plate nonlinear kinetics parameter test method under environment；

Fig. 2 is that the heat of the present invention is shaken the test flow chart of the nonlinear natural frequency of fiber composite plate under environment；

Fig. 3 is that the heat of the present invention is shaken the test flow chart of the nonlinear analog-circuit vibration shape of fiber composite plate under environment；

Fig. 4 is that the heat of the present invention is shaken the test flow chart of the nonlinear dampling of fiber composite plate under environment；

Fig. 5 is that the heat of the present invention overall structure of fiber composite plate nonlinear kinetics parameter test system under environment of shaking is shown It is intended to；

Fig. 6 is the overview of the vibration module of the specific embodiment of the invention；

Fig. 7 is the overview of the laser scanning vibration measuring module of the specific embodiment of the invention；

Fig. 8 is the overview and sectional view of the thermal environment simulation module of the specific embodiment of the invention；

Fig. 9 is the internal view of the thermal environment simulation module of the specific embodiment of the invention.

Embodiment

The heat for the present invention is shaken the flow of fiber composite plate nonlinear kinetics parameter test method under environment as shown in Figure 1 Figure, method of testing comprise the following steps：

The heat for being illustrated in figure 2 the present invention is shaken the test flow chart of the nonlinear natural frequency of fiber composite plate under environment, The method of testing of the nonlinear natural frequency of step 2 includes：

Step 2-1：By preliminary experiment, parsing or the method for finite element analysis, each rank of the preliminary tested composite plate of acquisition is intrinsic Frequency；

Step 2-2：Result based on analytical Calculation, it is determined that suitably response measuring point and feedback measuring point；

When it is implemented, the vibration of response measuring point is obtained by laser scanning vibration measuring module, the vibration for feeding back measuring point is led to Cross the acquisition of high temperature acceleration transducer.

Step 2-3：Test temperature is set by thermal environment simulation module, waits thermal environment in thermal environment simulation module to reach Stable state, from each rank intrinsic frequency obtained select first natural frequency carry out sweep check, using vibration module with The mode of basic excitation is just being swept by composite plate respectively under certain excitation amplitude and sweep velocity and the anti-frequency sweep swept is surveyed Try, and the vibratory response data of tested composite plate are gathered by the way of laser scanning, while to the vibratory response data of collection Treatment Analysis is carried out, to obtain the response curve of tested first natural frequency of the composite plate under the excitation amplitude；

When it is implemented, scanning band is set as the 75%~125% of the rank intrinsic frequency, at the same consider efficiency and Experimental precision determines suitable sweep velocity；In test process, data are carried out to tested thin plate using laser scanning vibration measuring module Collection, while finishing analysis are carried out to gathered data using Data Management Analysis module, the final tested composite plate of acquisition swashs at this Encourage the response curve of first natural frequency under amplitude.

Step 2-4：Excitation amplitude is adjusted according to order from low to high, repeats to carry out sweep check to tested composite plate, The response curve of corresponding a plurality of first natural frequency during obtaining different excitation amplitudes；Wherein, carried out in adjustment excitation amplitude In sweep check, changing rule of the first natural frequency with excitation amplitude can be obtained, if solid by recognizing the peak value of response curve There is frequency that downward trend is presented with the increase of excitation amplitude, then soft linear Stiffness is presented, can be scanned in follow-up each rank Tested in test by anti-frequency sweep；If the trend of increase is presented with the increase of excitation amplitude for intrinsic frequency, present Rigid linear Stiffness, it should be tested in follow-up each rank sweep test by just frequency sweep；

Step 2-5：According to the order of order from low to high, each rank intrinsic frequency is chosen successively and is scanned test, repeat Step 2-3 and step 2-4, until obtaining at this temperature in frequency range of interest, each rank corresponding to different excitation amplitudes is non-thread The response curve of property intrinsic frequency；

Step 2-6：The environment temperature raised successively in thermal environment simulation module treats testing temperature, repeat step 2-3 to all To step 2-5, to obtain the response curve for each rank nonlinear natural frequency that composite plate is shaken under environment in the heat of different temperatures.

The heat for being illustrated in figure 3 the present invention is shaken the test flow chart of the nonlinear analog-circuit vibration shape of fiber composite plate under environment, The method of testing of the nonlinear analog-circuit vibration shape of step 3 includes：

Step 3-1：Test temperature is set by thermal environment simulation module, waits thermal environment in thermal environment simulation module to reach Stable state：

Step 3-2：Each rank nonlinear natural frequency under the different excitation amplitudes obtained based on step 2, choose some and swash The first order nonlinear intrinsic frequency under amplitude is encouraged, composite plate is carried out by vibration module to determine frequency resonance excitation, and then excite it Reach resonance state；

Step 3-3：According to the phase of the response signal of each point in tested composite plate whether with phase or anti-phase, and then judge multiple Whether plywood if in energy sufficient resonance state if performs step 3-4 in the sufficient resonance state of energy, otherwise by Step increase excitation amplitude so that excitation performs step 3-4 again after meeting the test condition of Mode Shape；

Judge that composite plate whether in the sufficient resonance state of energy, specifically includes：

Step 3-3-1：Laser is scanned test along a fixed scanning direction under resonance excitation, to be answered The scanning response signal of plywood a line or a certain row；

Step 3-3-2：The time shaft of the scanning response signal of acquisition is divided into multiple periods, each period The response of a part of measuring point in scanning process is corresponded to respectively, with the sound of the raising, then part measuring point of division time segment number Answer response of the Step wise approximation in single measuring point；

Step 3-3-3：After the time domain vibratory response for obtaining several approximate single measuring points, FFT is carried out respectively, and Draw the amplitude-frequency response and phase-frequency response curve of these measuring points；

Step 3-3-4：Phase corresponding to peak response amplitude is extracted, and calculates the phase difference of adjacent spots, if it is close 0 ° or 180 °, then it is assumed that resonance response phenomenon is clearly；It is on the contrary, then it is assumed that the excitation energy of the excitation amplitude is not sufficient enough, It is not enough to effectively excite composite plate to reach the sufficient resonance state of energy, thus Mode Shape can not be carried out under the excitation amplitude Test.

Step 3-4：According to the scanning pattern and sweep speed of setting, the multirow of composite plate is evenly scanned using laser spots Or multiple row, the often vibratory response data of row or each column are obtained, and extract suitable vibratory response data；When it is implemented, using Laser scanning vibration measuring module scans composite plate, laser scanning vibration measuring module include laser vibration measurer and XY axles feeding guide rail, motor Deng.

The extraction criterion of vibratory response data is in step 3-4：

Step 3-4-1：Assuming that vibratory response data are obtained by row scanning pattern pattern, if often capable measuring point sum phase Together and it is p_m, it is scanning initial time t at the time of the 1st measuring point of scanning corresponds to₀, it is t at the time of completion corresponding to scanning_com, then The time difference τ of two neighboring measuring point is：

τ=t_com/(p_m-1) (1)

Often k-th of measuring point of row (k=1,2 ..., p_m) it is corresponding at the time of t_kFor：

Now, according to laser measuring point and sweep speed, time width corresponding to each scanning measuring point can be expressed as：

In formula, Δ t is time width；D is the diameter of laser measuring point, is 1mm~3mm；V is sweep speed, unit m/ s；

Vibratory response data corresponding to different measuring points are extracted in the laser scanning signal obtained from the test of every row, for k= 1, i.e. the 1st measuring point, take the t of oscillating scanning time-domain signal₀Moment is to t₀+ time Δt is the time domain waveform data of the measuring point；It is right In k=2 ..., p_m- 1, i.e. the 2nd measuring point to pth_m- 1 measuring point, take the t of oscillating scanning time-domain signal_k- 0.5 time Δt is to t_k + 0.5 time Δt is the time domain waveform data of the measuring point；For k=p_m, i.e. last measuring point takes oscillating scanning time-domain signal T_com- time Δt is to t_comMoment is the time domain waveform data of the measuring point.

The Criterion of Selecting of sweep speed is in step 3-4：

Step 3-4-2：In the research practice of composite plate Mode Shape is obtained using laser scanning vibration measuring module, find to sweep Retouch that speed is smaller, row or column spacing is smaller, then the vibration shape result obtained is more accurate, but can seriously reduce testing efficiency, in order to Scan efficiency and vibration mode test precision can be taken into account simultaneously, below by taking line-scan mode as an example, determine sweep speed v and between-line spacing Distance Y_MBetween relation, and formulate the Criterion of Selecting of rational sweep speed.

Assuming that complete the time t of certain row sweep test_comIt is represented by：

In formula, l is the length (scanning direction of corresponding line-scan mode) of length-composite plate of composite plate in the x-direction.

Assuming that with intrinsic sample frequency F_sTo carry out vibration shape sweep test, because per horizontal-scanning interval is all t_com.Cause This, the every size Q of row scan test data amount_cFor：

Q_c=F_s×t_com (5)

In line-scan mode at present, when between-line spacing distance is Y_MWhen, in order to ensure wire-frame model x and y side in Mode Shape Equal to response point interval, then the interval of loading response point also should be Y needed for wire-frame model y directions_M.Therefore, x directions are per line The points K of loading needed for frame model_xFor：

The then points K of loading needed for y directions each column wire-frame model_yFor：

Wherein, b is length of the width-composite plate of composite plate along Y-direction.

According to the time width Δ t of the selected good single measuring point of formula (3), and with intrinsic sample frequency F_sShaken to carry out mode Type sweep test, the points per loading needed for line frame model are K_x, then it is required loading data volume size Q_xFor：

Q_x=K_x×F_s×Δt (8)

Formula (6) is substituted into (8) to obtain

Because the amount of test data sum of every row is greater than equal to the sum that data volume is loaded needed for wire-frame model, can make The Criterion of Selecting of fixed following sweep speedFor

Formula (4), (5) and (6) is substituted into (10) in the lump, finally given between laser scan rate and sweep span (line-spacing) Relation：

According to the experience of wire frame modeling rendering in Mode Shape, in order to ensure the Mode Shape result of high quality, adjacent lines Spacing should be less than or 1/10th equal to composite plate length l, i.e. Y_M≤0.1l.Formula (11) can be reduced to

Formula (12) is the Criterion of Selecting of the sweep speed of laser scan rate, only whenPass through adding for scanning element Data are carried, can correctly obtain the Mode Shape of composite plate.MeanwhileValue is bigger, then can obtain more accurately mode and shake The result of type.

Step 3-5：Vibratory response data are handled, Frequency spectrum quality is preferable to obtain, and the vibration of high s/n ratio rings Answer data；

Specifically included when it is implemented, carrying out processing to vibratory response data：

Step 3-5-1：The vibratory response quality of data of sweep test acquisition is differentiated based on spectrum peak method of comparison, i.e., to shaking Dynamic response data carry out Fast Fourier Transform (FFT), and extract amplitude corresponding to each frequency content on frequency spectrum, judge harmonic frequency Whether corresponding peak value peak value corresponding with fundamental frequency meets formula below：

A_j/A₀≤ 1% (j=1,2 ...), (13)

In formula, A₀And A_jPeak value corresponding to fundamental frequency and j-th of harmonic frequency are corresponding respectively on the frequency spectrum of vibratory response data Peak value；If meeting above formula, prove that the Frequency spectrum quality of the signal is preferable, can be used to draw Mode Shape；Otherwise, should improve Test the quality of data of the Mode Shape obtained；

Step 3-5-2：Adding window and filtering process are carried out to the preferable vibratory response data of Frequency spectrum quality, obtain high s/n ratio Vibratory response data.

In order to reduce spectrum energy leakage, adding window is carried out to it, and take the higher hanning windows of amplitude accuracy of identification. In order to reject the background noise component in time-domain signal, LPF method should be used.

Step 3-6：Draw the composite plate first-order modal vibration shape；Specifically include：

Step 3-6-1：Defining transmission function expression formula is：

In formula, Z_i(ω) is the frequency domain response that the vibratory response data of the high s/n ratio of acquisition are carried out with FFT acquisition； Z_P(ω) is that the frequency domain of the response signal progress FFT acquisition at the reference point P obtained to high temperature resistant acceleration transducer rings Should；A, B, C are different point positions；

When with a certain resonant frequency ω_rWhen encouraging composite plate, it is assumed that when coupling is not present in each rank mode, transport function is near It is like formula：

In formula, φ_irAnd φ_PrIt is component value of the composite plate r ranks Mode Shape at measuring point i and P respectively；

But in engineering in fact, in order to reduce influence of the outside noise to result, transport function is typically rung by mobile The crosspower spectrum G with reference response point should be put_iP(ω) divided by reference response point auto-power spectrum G_PP(ω) is obtained, that is, obtained Final transmission function formula：

Step 3-6-2：It is according to final transmission function formula that the data of each point are unified to a time, then draw the vibration shape； According to the size of composite plate, the wire-frame model in Mode Shape is drawn first；Then, will be obtained under the first rank some excitation amplitude The amplitude of the transport function of each measuring point obtained carries out Regularization, turns to nondimensional expression formula；Finally, by regularization The amplitude of each measuring point transport function after processing, it is loaded on the coordinate value of each self-corresponding wire-frame model measuring point, simultaneously will The phase of each measuring point transport of transport function also loads in the lump, and can realize that composite plate is corresponding under some excitation amplitude The drafting of the first step mode vibration shape.

Step 3-7：Excitation amplitude is adjusted according to order from low to high, repeat step 3-2 is sequentially completed to step 3-6 The drafting of composite plate first order nonlinear Mode Shape under different excitation amplitudes；

Step 3-8：According to the order of order from low to high, the non-thread of other orders under some excitation amplitude is chosen successively Property intrinsic frequency, and by vibration module to composite plate carry out determine frequency resonance excitation, and repeat step 3-2 to step 3-7, to obtain Obtain each rank nonlinear analog-circuit vibration shape of the composite plate in different excitation amplitudes at this temperature；

Step 3-9：The environment temperature raised successively in thermal environment simulation module treats testing temperature, repeat step 3-2 to all To step 3-8, to obtain each rank nonlinear analog-circuit vibration shape that composite plate is shaken under environment in the heat of different temperatures.

Fig. 4 is that the heat of the present invention is shaken the test flow chart of the nonlinear dampling of fiber composite plate under environment, non-thread in step 4 Property damping test include：

Step 4-1：Test temperature is set by thermal environment simulation module, waits thermal environment in thermal environment simulation module to reach Stable state；

Step 4-2：Using each rank nonlinear natural frequency under the different excitation amplitudes obtained in step 3 and step 4 and The nonlinear analog-circuit vibration shape, it is determined that during test response point position, it is complicated for the node-line of fiber-reinforced composite materials structures, And local mode it is abundant the characteristics of, when actually measuring, in order to avoid response point is arranged on the node or nodel line of structure, choosing Select at least three response point and carry out vibratory response data acquisition, after comparative analysis, determine optimal response point position； Meanwhile in order to reduce the test error of damping parameter, test should select non-contacting vibration measuring mode to obtain response signal.

Step 4-3：Test temperature is set by thermal environment simulation module, waits thermal environment in thermal environment simulation module to reach Stable state；Record time domain deamplification of each rank nonlinear natural frequency under its resonance state under different excitation amplitudes；

Physical record method is as follows：

Step 4-3-1：Each rank nonlinear natural frequency under the different excitation amplitudes obtained using step 2, chooses some First order nonlinear intrinsic frequency under excitation amplitude, single order is carried out to composite plate by vibration module and determines frequency resonance excitation, and then It is excited to reach resonance state；

Step 4-3-2：Resonance state to be achieved and after a period of stabilisation, stop excitation, recording should under resonance state Time domain deamplification corresponding to the first order nonlinear intrinsic frequency of excitation amplitude；

Step 4-3-3：Excitation amplitude, repeat step 4-3-1 and step 4-3-2, note are adjusted according to order from low to high Time domain deamplification corresponding to the first order nonlinear intrinsic frequency of excitation amplitude of interest under each resonance state under record；

Step 4-3-4：According to the order of order from low to high, the nonlinear natural frequency of other orders is chosen successively, it is heavy Multiple step 4-3-1 to step 4-3-3, record each rank intrinsic frequency of interest under different excitation amplitudes under its resonance state when Domain deamplification.

Step 4-4：EMD decomposition is carried out to the time domain deamplification of each rank intrinsic frequency, background noise is excluded and other is dry The influence of factor is disturbed, while judges whether obtained deamplification is resonance decay response, and then is improved in subsequent step The precision of Hilbert conversion；

Step 4-5：The modal mass of composite plate is calculated, because in actual test, composite plate is more in one end constraint, one end Free cantilever position, below by taking cantilever composite plate as an example, provide calculate fiber reinforced compound board modal mass method.It is first First pass through two-dimension beam function method and the model function of vibration of composite plate is expressed as form：

A in formula_ijIt is the undetermined coefficient relevant with excitation amplitude, X_i(x) represent to fix along one end during x directions, one end is certainly By the i-th rank mode function of beam, Y_i(y) the jth rank mode function along beam with free ends during y directions is represented；P, q are respective mould The maximum order that state is considered, the modal mass m (x, y) of thin plate optional position, its expression formula can be obtained using the model function of vibration For：

In formula, S is the area of composite plate, and ρ is its density, and H is gauge of sheet.

Step 4-6：When carrying out Hilbert conversion to the time domain deamplification after EMD decomposition, and obtaining different excitation amplitudes Each rank nonlinear dampling, specifically include：

Step 4-6-1：The rigidity and damping parameter of fibrous composite change with the amplitude of system, thus For this attenuation process, it is believed that its rigidity and damping change with the change of die-away time, can be declined above-mentioned Subtract process with following single-degree-of-freedom equation to be described：

In formula, m=m (x, y) is the modal mass of fiber composite plate, and c (t) and k (t) then distinguish table fiber reinforced compound board Time-varying modal damping and rigidity, q (t) be the time domain deamplification under corresponding modal coordinate；

Step 4-6-2：Time domain deamplification after being decomposed to EMD carries out Hilbert conversion, and conversion expression formula is represented For：

In formula, " H " represents Hilbert conversion,It is the time domain deamplification after conversion, τ represents some of deamplification Moment；

After carrying out Hilbert conversion, the signal after conversion and original time domain deamplification can be merged, and obtain One group of new signal Analysis Q (t), its expression formula are：

New signal Analysis Q (t) envelope A (t) and instantaneous phase ψ (t) can be expressed as

Instantaneous phase ψ (t) is differentiated, then can obtain real-time frequency ω (t), i.e.,

ψ ' (t)=ω (t) (24)

Hilbert conversion is carried out to formula (19), following formula can be obtained：

When carrying out Hilbert conversion to formula (19), it is assumed that time-varying modal damping c (t) and time-varying rigidity k (t) is stable Change, i.e., in conversion process, c (t) and k (t) are constant, i.e.,

Formula (25) both ends are multiplied by into imaginary unit j to be added with formula (19), the equation of motion expressed with signal Analysis can be obtained, I.e.

, can be by the single order and second dervative of signal Analysis in formula (28) using formula (21) to formula (23)With envelope A (t) expressed with real-time frequency ω (t), i.e.,

Formula (29) and formula (30) are updated to formula (28), can be obtained after arrangement

The real and imaginary parts of formula (31) are made to be equal to zero, so that it may which obtain composite structural system has the non-thread of amplitude dependence Property rigidity and the expression formula of damping

Step 4-6-3：After each rank time domain deamplification for obtaining composite plate, Hilbert conversion process is carried out to it respectively, The envelope A (t) and real-time frequency ω (t) of each rank time domain deamplification are further obtained using formula (22) and formula (24), so After be taken to formula (33), then can obtain the time-varying damping parameter c (t) of tested composite plate；

According to above formula, it is converted as conventional damping ratios ζ (t)：

Step 4-7：The environment temperature raised successively in thermal environment simulation module treats testing temperature, repeat step 4-2 to all To step 4-6, to obtain each rank nonlinear dampling that composite plate is shaken under environment in the heat of different temperatures.

The method of the present invention applies also for testing the nonlinear kinetics parameter of fiber composite plate under isoperibol, Detailed process is as follows：

1st, nonlinear natural frequency is tested under isoperibol：On the vibration module that thermal environment simulation module is fixed to, The temperature of thermal environment simulation module is adjusted to default minimum temperature, such as 50 degree.Thermal environment in module is waited to reach stable state And continue one hour.According to each rank nonlinear natural frequency under the different excitation amplitudes under the method test thermal environment of step 2. The stable state duration length of thermal environment in thermal environment simulation module is adjusted, then is raised successively in thermal environment simulation module Environment temperature treat testing temperature to all, the method for testing of nonlinear natural frequency in repeat step 2, complete fiber composite plate and exist Nonlinear natural frequency corresponding to different excitation amplitudes under isoperibol.

2nd, the nonlinear analog-circuit vibration shape is tested under isoperibol：On the vibration module that thermal environment simulation module is fixed to, The temperature of thermal environment simulation module is adjusted to default minimum temperature, such as 50 degree.Thermal environment in module is waited to reach stable state Afterwards, and one hour is continued.Choose and test nonlinear natural frequency under thermal environment, different excitation width are tested according to the method for step 3 Each rank nonlinear analog-circuit vibration shape under degree.The stable state duration length of thermal environment in thermal environment simulation module is adjusted, The environment temperature raised successively again in thermal environment simulation module treats testing temperature to all, fiber composite plate difference in repeat step 3 The method of testing of the nonlinear analog-circuit vibration shape corresponding to excitation amplitude, complete different excitation amplitudes pair under fiber composite plate isoperibol The test for the nonlinear analog-circuit vibration shape answered.

3rd, nonlinear dampling is tested under isoperibol：On the vibration module that thermal environment simulation module is fixed to, by heat The temperature of environmental simulation module is adjusted to default minimum temperature, such as 50 degree.After thermal environment reaches stable state in wait module, and Continue one hour.According to the nonlinear natural frequency and the test result of Mode Shape under different excitation amplitudes in thermal environment, section The position that ground determines response point during test is learned, the non-linear resistance of each rank tested according still further to the method for step 4 under different excitation amplitudes Buddhist nun.The stable state duration length of thermal environment in thermal environment simulation module is adjusted, then raises thermal environment simulation mould successively Environment temperature in block treats testing temperature to all, non-linear resistance corresponding to fiber composite plate difference excitation amplitude in repeat step 4 The method of testing of Buddhist nun, complete the test of fiber composite plate nonlinear dampling corresponding to different excitation amplitudes under isoperibol.

The heat for being illustrated in figure 5 the present invention is shaken the entirety of fiber composite plate nonlinear kinetics parameter test system under environment Structural representation.Test system includes：At laser scanning vibration measuring module 3, thermal environment simulation module 4, vibration module 5 and data Manage analysis module 12.Wherein, vibration module 5, for entering row energization to composite plate as driving frequency using each rank intrinsic frequency.Swash Optical scanning vibration measuring module 3, for being scanned to composite plate to obtain vibratory response data.Data Management Analysis module 12, use In being handled vibratory response data to test nonlinear kinetics parameter.Thermal environment simulation module 4, for being wanted according to test Seek control test environment temperature.

As shown in figure 5, laser scanning vibration measuring module 3, thermal environment simulation module 4, vibration module 5 and Data Management Analysis Module 12 is arranged in integral installation bin 1, and alarm lamp 2 and temperature control and detection faces are also equipped with integral installation bin 1 Plate 6, integral installation bin 1 are provided with castor 7 to be moved easily.

As shown in fig. 6, vibration module 5 includes installs fixture 14, mounting platform 15, vibrator 17, the and of power amplifier 13 Support frame 18.Vibrator 17 is arranged in the base plane of support frame 18, and is connected with power amplifier 13, vibrator 17 Top is provided with exciting rod.Exciting rod withstands on the bottom of mounting platform 15, enters row energization to mounting platform 15 during test.Installation is flat The top of platform 15 is equipped with stuck-module by bolt.The top surface of mounting platform 15 is provided with constant worm pich hole, bottom surface corner be provided with four it is non- The circular hole of insertion can be used for limiting spring 16, and hammer vibration energy can be passed to the installation folder of composite plate in a manner of basic excitation Tool 14, feedback transducer is provided with mounting platform 15 can ensure the vibrational excitation of amplitude-controllable；The lower end of spring 16 and support Frame 18 is connected.Installs fixture 14 is bolted on mounting platform 15, by adjusting the quantity using installs fixture 14, More arbitrary boundary conditions such as unilateral, opposite side needed for test compound plate, arbitrary loading can be intended.

As shown in fig. 7, laser scanning vibration measuring module 3 includes：Connecting shaft 19, shaft coupling 20,21,45 ° of stepper motor are reflective Mirror 22, I-shaped slide unit 23, laser vibration measurer 24, vialog mounting bracket 25 and stepper motor driver.

Laser vibration measurer 24 is arranged in vialog mounting bracket 25 by bolt, while vialog mounting bracket 25 passes through Bolt is connected with I-shaped slide unit 23；I-shaped slide unit 23 is bolted on the top of the opening of integral installation cabinet 1.Vialog is pacified 45 ° of reflective mirrors 22 are provided with by fix bar on dress support 25, for adjusting optical circuit path emitted by laser vibration measurer 24.Laser Vialog 24 realizes movement by the motion of I-shaped slide unit 23, and the motion path of laser vibration measurer 24 is by two models 86HS45 stepper motor 21 controls the motion of its orthogonal direction respectively；Stepper motor 21 can be by stepper motor driver 10 and R- 10 controllers 11 control and carry out feed motion within the specific limits.

As shown in figure 5, Data Management Analysis module 12 is soft including notebook computer 9, Portable acquiring instrument 8 and vibration analysis Part, it is to carry out data collection and analysis, driver control and temperature controlled indispensable module.

As shown in figure 8, thermal environment simulation module 4 includes：Heat insulating box 26, heat insulation pedestal 27, thermocouple 28, fan 29, Carbon fiber heating tube 30 and observation window 31.The heat insulating box 26 is made of high-temperature resistant thermal insulating material, for preventing heat Loss, ensure the demand of experimental temperature.The front of heat insulating box 26 and top surface are provided with observation window 31 simultaneously, and observation window 31 is using anti- High Temperature Optical glass is made, and is easy to improve the precision of laser vibration measurer while observation.The carbon fiber heating tube 30 passes through branch Seat is arranged on inside heat insulating box 26, for producing heat after energization, provides a hot environment for the inside of heat insulating box 26, together When in the inside both sides of heat insulating box 26 be mounted with the fan 29 for accelerating thermal cycle, make the temperature in hot box 26 as far as possible equal It is even.Thermocouple 28 is distributed in the corner of the top of carbon fiber heating tube 30, and four thermocouples 28 detect environment temperature simultaneously, pass through control Device processed is compared, and determines the actual temperature in casing, and is corrected and adjusts.The bottom opening of heat insulating box 26, It is connected by screw with heat insulation pedestal 27.

Carry out heat shake test when, fiber composite plate is fixed on to the mounting platform 15 of vibration module 5 by installs fixture 14 On, mounting platform 15 is stretched into inside the heat insulating box 26 by the bottom opening of heat insulating box 26, mounting platform 15 and every Hot base 27 is realized by flexible glue bar and is tightly connected；Heat insulation pedestal 27 and the precision-fit of heat insulating box 26 and mounting platform 15, Be advantageous to prevent heat losses, play sealing function.Laser scanning vibration measuring module 3 is arranged on the top of the heat insulating box 26, Laser is scanned through the high temperature resistance optical glass to fiber composite plate during test.

Presently preferred embodiments of the present invention is the foregoing is only, the thought being not intended to limit the invention is all the present invention's Within spirit and principle, any modification, equivalent substitution and improvements made etc., it should be included in the scope of the protection.

Claims

The fiber composite plate nonlinear kinetics parameter test method under environment 1. a kind of heat is shaken, it is characterised in that including following step Suddenly：

Step 1：Build heat to shake test environment, fiber composite plate is fixed on to the mounting platform of vibration module by installs fixture On, mounting platform is stretched into the heat insulating box of thermal environment simulation module and by soft adhesive tape sealing, by laser scanning vibration measuring mould Block is arranged above heat insulating box, makes laser through the high temperature resistance optical glass of heat insulating box top surface to fiber composite plate during test It is scanned；

Step 2：Test temperature is set by thermal environment simulation module, each rank intrinsic frequency to be tested composite plate is used as excitation frequency Rate carries out sweep check respectively to composite plate under certain excitation amplitude, is shaken environment in the heat of different temperatures with obtaining composite plate Under each rank nonlinear natural frequency response curve；

Step 3：Test temperature is set by thermal environment simulation module, each rank that the heat obtained using test is shaken under environment is non-linear Intrinsic frequency, composite plate is carried out by vibration module and determines frequency resonance excitation, and then excite it to reach resonance state, recycled and swash Luminous point evenly scans the multirow or multiple row of composite plate, to obtain the often vibratory response data of row or each column, and from vibratory response The vibration shape is identified in data and draws Mode Shape, it is non-linear solid in each rank that the heat of different temperatures is shaken under environment to obtain composite plate Mode Shape；

Step 4：Test temperature is set by thermal environment simulation module, utilizes the non-linear intrinsic frequency obtained in step 2 and step 3 The result of rate and Mode Shape, it is determined that during test response point position, and test compound plate shakes under environment in the heat of different temperatures Each rank nonlinear dampling.
2. heat as claimed in claim 1 is shaken, fiber composite plate nonlinear kinetics parameter test method, its feature exist under environment In the step 2 includes：

Step 2-1：It is preliminary to obtain each rank intrinsic frequency of tested composite plate by preliminary experiment, parsing or the method for finite element analysis；

Step 2-2：Result based on analytical Calculation, it is determined that suitably response measuring point and feedback measuring point；

Step 2-3：Test temperature is set by thermal environment simulation module, waits thermal environment in thermal environment simulation module to reach stable State, first natural frequency is selected to carry out sweep check from each rank intrinsic frequency obtained, using vibration module with basis The mode of excitation is just being swept under certain excitation amplitude and sweep velocity by composite plate respectively and the anti-sweep check swept, and Gather the vibratory response data of tested composite plate by the way of laser scanning, at the same to the vibratory response data of collection at Reason analysis, to obtain the response curve of tested first natural frequency of the composite plate under the excitation amplitude；

Step 2-4：Excitation amplitude is adjusted according to order from low to high, repeats to carry out sweep check to tested composite plate, to obtain The response curve of corresponding a plurality of first natural frequency when obtaining different excitation amplitudes；Wherein, frequency sweep is carried out in adjustment excitation amplitude In test, changing rule of the first natural frequency with excitation amplitude can be obtained, if intrinsic frequency by recognizing the peak value of response curve Downward trend is presented with the increase of excitation amplitude in rate, can be surveyed in follow-up each rank sweep test by anti-frequency sweep Examination；, should be in follow-up each rank sweep test by just sweeping if the trend of increase is presented with the increase of excitation amplitude for intrinsic frequency Frequency sweep is tested；

Step 2-5：According to the order of order from low to high, each rank intrinsic frequency is chosen successively and is scanned test, repeat step 2-3 and step 2-4, until obtaining at this temperature in frequency range of interest, each rank is non-linear solid corresponding to different excitation amplitudes There is the response curve of frequency；

Step 2-6：The environment temperature raised successively in thermal environment simulation module treats testing temperature, repeat step 2-3 to step to all Rapid 2-5, to obtain the response curve for each rank nonlinear natural frequency that composite plate is shaken under environment in the heat of different temperatures.
3. heat as claimed in claim 1 is shaken, fiber composite plate nonlinear kinetics parameter test method, its feature exist under environment In the step 3 includes：

Step 3-1：Test temperature is set by thermal environment simulation module, waits thermal environment in thermal environment simulation module to reach stable State：

Step 3-2：Each rank nonlinear natural frequency under the different excitation amplitudes obtained based on step 2, choose some excitation width First order nonlinear intrinsic frequency under degree, carries out determining frequency resonance excitation, and then excite it to reach by vibration module to composite plate Resonance state；

Step 3-3：According to the phase of the response signal of each point in tested composite plate whether with phase or anti-phase, and then judge composite plate Whether in the sufficient resonance state of energy, step 3-4 is performed if in the sufficient resonance state of energy, is otherwise progressively increased Big excitation amplitude so that excitation performs step 3-4 again after meeting the test condition of Mode Shape；

Step 3-4：According to the scanning pattern and sweep speed of setting, the multirow or more of composite plate is evenly scanned using laser spots Row, the often vibratory response data of row or each column are obtained, and extract suitable vibratory response data；

Step 3-5：Vibratory response data are handled, Frequency spectrum quality is preferable to obtain, the vibratory response number of high s/n ratio According to；

Step 3-6：Draw the composite plate first-order modal vibration shape；

Step 3-7：Excitation amplitude is adjusted according to order from low to high, repeat step 3-2 is sequentially completed difference to step 3-6 The drafting of composite plate first order nonlinear Mode Shape under excitation amplitude；

Step 3-8：According to the order of order from low to high, the non-linear solid of other orders under some excitation amplitude is chosen successively There is frequency, and composite plate is carried out by vibration module and determines frequency resonance excitation, and repeat step 3-2 to step 3-7, to be somebody's turn to do At a temperature of each rank nonlinear analog-circuit vibration shape of the composite plate in different excitation amplitudes；

Step 3-9：The environment temperature raised successively in thermal environment simulation module treats testing temperature, repeat step 3-2 to step to all Rapid 3-8, to obtain each rank nonlinear analog-circuit vibration shape that composite plate is shaken under environment in the heat of different temperatures.
4. heat as claimed in claim 3 is shaken, fiber composite plate nonlinear kinetics parameter test method, its feature exist under environment In the extraction criterion of vibratory response data is in the step 3-4：

Assuming that vibratory response data are obtained by row scanning pattern pattern, if often capable measuring point sum is identical and is p_m, scanning the It is scanning initial time t at the time of 1 measuring point corresponds to₀, it is t at the time of completion corresponding to scanning_com, then two neighboring measuring point Time difference, τ was：

τ=t_com/(p_m-1) (1)

Often k-th of measuring point of row (k=1,2 ..., p_m) it is corresponding at the time of t_kFor：

<mrow> <msub> <mi>t</mi> <mi>k</mi> </msub> <mo>=</mo> <msub> <mi>t</mi> <mn>0</mn> </msub> <mo>+</mo> <mfrac> <msub> <mi>t</mi> <mrow> <mi>c</mi> <mi>o</mi> <mi>m</mi> </mrow> </msub> <mrow> <mo>(</mo> <msub> <mi>p</mi> <mi>m</mi> </msub> <mo>-</mo> <mn>1</mn> <mo>)</mo> </mrow> </mfrac> <mrow> <mo>(</mo> <mi>k</mi> <mo>-</mo> <mn>1</mn> <mo>)</mo> </mrow> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>2</mn> <mo>)</mo> </mrow> </mrow>

Now, according to laser measuring point and sweep speed, time width corresponding to each scanning measuring point can be expressed as：

<mrow> <mi>&Delta;</mi> <mi>t</mi> <mo>&le;</mo> <mfrac> <mi>d</mi> <mi>v</mi> </mfrac> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>3</mn> <mo>)</mo> </mrow> </mrow>

In formula, Δ t is time width；D is the diameter of laser measuring point, is 1mm~3mm；V is sweep speed, unit m/s；

Vibratory response data corresponding to different measuring points are extracted from the laser scanning signal that obtains of every row test, for k=1, i.e., 1st measuring point, take the t of oscillating scanning time-domain signal₀Moment is to t₀+ time Δt is the time domain waveform data of the measuring point；For k= 2,…,p_m- 1, i.e. the 2nd measuring point to pth_m- 1 measuring point, take the t of oscillating scanning time-domain signal_k- 0.5 time Δt is to t_k+0.5 Time Δt is the time domain waveform data of the measuring point；For k=p_m, i.e. last measuring point takes oscillating scanning time-domain signal t_com- time Δt is to t_comMoment is the time domain waveform data of the measuring point.
5. heat as claimed in claim 3 is shaken, fiber composite plate nonlinear kinetics parameter test method, its feature exist under environment In carrying out processing to vibratory response data in the step 3-5 and specifically include：

Step 3-5-1：The vibratory response quality of data of sweep test acquisition is differentiated based on spectrum peak method of comparison, i.e., vibration is rung Answer data to carry out Fast Fourier Transform (FFT), and extract amplitude corresponding to each frequency content on frequency spectrum, judge that harmonic frequency is corresponding Peak value peak value corresponding with fundamental frequency whether meet formula below：

A_j/A₀≤ 1% (j=1,2 ...), (13)

In formula, A₀And A_jPeak corresponding to peak value corresponding to fundamental frequency and j-th of harmonic frequency respectively on the frequency spectrum of vibratory response data Value；If meeting above formula, prove that the Frequency spectrum quality of the signal is preferable, can be used to draw Mode Shape；Otherwise, test should be improved The quality of data of the Mode Shape of acquisition；

Step 3-5-2：Adding window and filtering process are carried out to the preferable vibratory response data of Frequency spectrum quality, obtain shaking for high s/n ratio Dynamic response data.
6. heat as claimed in claim 3 is shaken, fiber composite plate nonlinear kinetics parameter test method, its feature exist under environment In the step 3-6 is specifically included：

Step 3-6-1：Defining transmission function expression formula is：

<mrow> <msub> <mi>&gamma;</mi> <mi>i</mi> </msub> <mrow> <mo>(</mo> <mi>&omega;</mi> <mo>)</mo> </mrow> <mo>=</mo> <mfrac> <mrow> <msub> <mi>Z</mi> <mi>i</mi> </msub> <mrow> <mo>(</mo> <mi>&omega;</mi> <mo>)</mo> </mrow> </mrow> <mrow> <msub> <mi>Z</mi> <mi>P</mi> </msub> <mrow> <mo>(</mo> <mi>&omega;</mi> <mo>)</mo> </mrow> </mrow> </mfrac> <mo>,</mo> <mi>i</mi> <mo>=</mo> <mi>A</mi> <mo>,</mo> <mi>B</mi> <mo>,</mo> <mi>C</mi> <mo>...</mo> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>14</mn> <mo>)</mo> </mrow> </mrow>

In formula, Z_i(ω) is the frequency domain response that the vibratory response data of the high s/n ratio of acquisition are carried out with FFT acquisition；Z_P (ω) is the frequency domain response of the response signal progress FFT acquisition at the reference point P obtained to high temperature resistant acceleration transducer； A, B, C are different point positions；

When with a certain resonant frequency ω_rWhen encouraging composite plate, it is assumed that when coupling is not present in each rank mode, transport approximation to function is public Formula is：

<mrow> <msub> <mi>&gamma;</mi> <mi>i</mi> </msub> <mrow> <mo>(</mo> <mi>&omega;</mi> <mo>)</mo> </mrow> <mo>=</mo> <mfrac> <mrow> <msub> <mi>Z</mi> <mi>i</mi> </msub> <mrow> <mo>(</mo> <mi>&omega;</mi> <mo>)</mo> </mrow> </mrow> <mrow> <msub> <mi>Z</mi> <mi>P</mi> </msub> <mrow> <mo>(</mo> <mi>&omega;</mi> <mo>)</mo> </mrow> </mrow> </mfrac> <mo>&ap;</mo> <mfrac> <msub> <mi>&phi;</mi> <mrow> <mi>i</mi> <mi>r</mi> </mrow> </msub> <msub> <mi>&phi;</mi> <mi>Pr</mi> </msub> </mfrac> <mo>,</mo> <mi>i</mi> <mo>=</mo> <mi>A</mi> <mo>,</mo> <mi>B</mi> <mo>,</mo> <mi>C</mi> <mo>...</mo> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>15</mn> <mo>)</mo> </mrow> </mrow>

In formula, φ_irAnd φ_PrIt is component value of the composite plate r ranks Mode Shape at measuring point i and P respectively；

In order to reduce influence of the outside noise to result, transport function typically passes through the mutual of mobile response point and reference response point Power spectrum G_iP(ω) divided by reference response point auto-power spectrum G_PP(ω) is obtained, that is, is obtained final transmission function formula：

<mrow> <msub> <mi>&gamma;</mi> <mi>i</mi> </msub> <mrow> <mo>(</mo> <mi>&omega;</mi> <mo>)</mo> </mrow> <mo>&ap;</mo> <mfrac> <mrow> <msub> <mi>Z</mi> <mi>i</mi> </msub> <mrow> <mo>(</mo> <mi>&omega;</mi> <mo>)</mo> </mrow> <msup> <msub> <mi>Z</mi> <mi>P</mi> </msub> <mo>*</mo> </msup> </mrow> <mrow> <msub> <mi>Z</mi> <mi>P</mi> </msub> <mrow> <mo>(</mo> <mi>&omega;</mi> <mo>)</mo> </mrow> <msup> <msub> <mi>Z</mi> <mi>P</mi> </msub> <mo>*</mo> </msup> </mrow> </mfrac> <mo>=</mo> <mfrac> <mrow> <msub> <mi>G</mi> <mrow> <mi>i</mi> <mi>P</mi> </mrow> </msub> <mrow> <mo>(</mo> <mi>&omega;</mi> <mo>)</mo> </mrow> </mrow> <mrow> <msub> <mi>G</mi> <mrow> <mi>P</mi> <mi>P</mi> </mrow> </msub> <mrow> <mo>(</mo> <mi>&omega;</mi> <mo>)</mo> </mrow> </mrow> </mfrac> <mo>,</mo> <mi>i</mi> <mo>=</mo> <mi>A</mi> <mo>,</mo> <mi>B</mi> <mo>,</mo> <mi>C</mi> <mo>...</mo> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>16</mn> <mo>)</mo> </mrow> </mrow>

Step 3-6-2：It is according to final transmission function formula that the data of each point are unified to a time, then draw the vibration shape；According to The size of composite plate, the wire-frame model in Mode Shape is drawn first；Then, will obtain under the first rank some excitation amplitude The amplitude of the transport function of each measuring point carries out Regularization, turns to nondimensional expression formula；Finally, by Regularization The amplitude of each measuring point transport function afterwards, it is loaded on the coordinate value of each self-corresponding wire-frame model measuring point, while will transmits The phase of each measuring point transport of rate function also loads in the lump, and can realize composite plate corresponding first under some excitation amplitude The drafting of rank Mode Shape.
7. heat as claimed in claim 1 is shaken, fiber composite plate nonlinear kinetics parameter test method, its feature exist under environment In the step 4 specifically includes：

Step 4-1：Test temperature is set by thermal environment simulation module, waits thermal environment in thermal environment simulation module to reach stable State；

Step 4-2：Utilize each rank nonlinear natural frequency under the different excitation amplitudes obtained in step 2 and step 3 and non-thread Property Mode Shape, it is determined that test when response point position, and select at least three response point carry out vibratory response data acquisition, warp After comparative analysis, optimal response point position is determined；

Step 4-3：Test temperature is set by thermal environment simulation module, waits thermal environment in thermal environment simulation module to reach stable State；Record time domain deamplification of each rank nonlinear natural frequency under its resonance state under different excitation amplitudes；

Step 4-4：EMD decomposition is carried out to the time domain deamplification of each rank nonlinear natural frequency, excludes background noise and other The influence of disturbing factor；

Step 4-5：The modal mass of composite plate is calculated, is first expressed as the model function of vibration of composite plate by two-dimension beam function method Following form：

<mrow> <mi>W</mi> <mrow> <mo>(</mo> <mi>x</mi> <mo>,</mo> <mi>y</mi> <mo>)</mo> </mrow> <mo>=</mo> <munderover> <mo>&Sigma;</mo> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>p</mi> </munderover> <munderover> <mo>&Sigma;</mo> <mrow> <mi>j</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>q</mi> </munderover> <msub> <mi>A</mi> <mrow> <mi>i</mi> <mi>j</mi> </mrow> </msub> <msub> <mi>X</mi> <mi>i</mi> </msub> <mrow> <mo>(</mo> <mi>x</mi> <mo>)</mo> </mrow> <msub> <mi>Y</mi> <mi>j</mi> </msub> <mrow> <mo>(</mo> <mi>y</mi> <mo>)</mo> </mrow> <mo>,</mo> <mi>i</mi> <mo>=</mo> <mn>1</mn> <mo>,</mo> <mn>2</mn> <mo>,</mo> <mn>3</mn> <mo>...</mo> <mo>,</mo> <mi>&alpha;</mi> <mo>;</mo> <mi>j</mi> <mo>=</mo> <mn>1</mn> <mo>,</mo> <mn>2</mn> <mo>,</mo> <mn>3</mn> <mo>...</mo> <mo>,</mo> <mi>&beta;</mi> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>17</mn> <mo>)</mo> </mrow> </mrow>

A in formula_ij, it is the undetermined coefficient relevant with excitation amplitude, X_i(x) represent to fix along one end during x directions, one end free beam The i-th rank mode function, Y_i(y) the jth rank mode function along beam with free ends during y directions is represented；P, q are respective mode institute The maximum order of consideration, the modal mass m (x, y) of thin plate optional position can be obtained using the model function of vibration, and its expression formula is：

<mrow> <mi>m</mi> <mrow> <mo>(</mo> <mi>x</mi> <mo>,</mo> <mi>y</mi> <mo>)</mo> </mrow> <mo>=</mo> <munder> <mrow> <mo>&Integral;</mo> <mo>&Integral;</mo> </mrow> <mi>s</mi> </munder> <msup> <mi>&rho;HW</mi> <mn>2</mn> </msup> <mrow> <mo>(</mo> <mi>x</mi> <mo>,</mo> <mi>y</mi> <mo>)</mo> </mrow> <mi>d</mi> <mi>x</mi> <mi>d</mi> <mi>y</mi> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>18</mn> <mo>)</mo> </mrow> </mrow>

In formula, S is the area of composite plate, and ρ is its density, and H is gauge of sheet；

Step 4-6：Time domain deamplification after being decomposed to EMD carries out Hilbert conversion, and obtains composite plate in different excitation width Each rank nonlinear dampling when spending；

Step 4-7：The environment temperature raised successively in thermal environment simulation module treats testing temperature, repeat step 4-2 to step to all Rapid 4-6, to obtain each rank nonlinear dampling that composite plate is shaken under environment in the heat of different temperatures.
8. heat as claimed in claim 7 is shaken, fiber composite plate nonlinear kinetics parameter test method, its feature exist under environment In, in the step 4-3 specific recording method include：

Step 4-3-1：Each rank nonlinear natural frequency under the different excitation amplitudes obtained using step 2, chooses some excitation First order nonlinear intrinsic frequency under amplitude, single order is carried out to composite plate by vibration module and determines frequency resonance excitation, and then excited It reaches resonance state；

Step 4-3-2：Resonance state to be achieved and after a period of stabilisation, stop excitation, record the excitation under resonance state Time domain deamplification corresponding to the first order nonlinear intrinsic frequency of amplitude；

Step 4-3-3：Excitation amplitude, repeat step 4-3-1 and step 4-3-2 are adjusted according to order from low to high, is recorded Time domain deamplification corresponding to the first order nonlinear intrinsic frequency of excitation amplitude of interest under each resonance state；

Step 4-3-4：According to the order of order from low to high, the nonlinear natural frequency of other orders is chosen successively, repeats to walk Rapid 4-3-1 to step 4-3-3, records time domain of each rank intrinsic frequency of interest under its resonance state under different excitation amplitudes and declines Cut signal.
9. heat as claimed in claim 7 is shaken, fiber composite plate nonlinear kinetics parameter test method, its feature exist under environment In the step 4-6 is specifically included：

Step 4-6-1：The rigidity and damping parameter of fibrous composite change with the amplitude of system, thus for This attenuation process, it is believed that its rigidity and damping change with the change of die-away time, can decay above-mentioned Journey is described with following single-degree-of-freedom equation：

<mrow> <mi>m</mi> <mover> <mi>q</mi> <mo>&CenterDot;&CenterDot;</mo> </mover> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>+</mo> <mi>c</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mover> <mi>q</mi> <mo>&CenterDot;</mo> </mover> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>+</mo> <mi>k</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mi>q</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>=</mo> <mn>0</mn> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>19</mn> <mo>)</mo> </mrow> </mrow>

In formula, m=m (x, y) is the modal mass of fiber composite plate, and c (t) and k (t) then represent the time-varying modal of composite plate respectively Damping and rigidity, q (t) are the time domain deamplification under corresponding modal coordinate；

Step 4-6-2：Time domain deamplification after being decomposed to EMD carries out Hilbert conversion, and conversion expression formula is expressed as：

<mrow> <mover> <mi>q</mi> <mo>~</mo> </mover> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>=</mo> <mi>H</mi> <mo>&lsqb;</mo> <mi>q</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>&rsqb;</mo> <mo>=</mo> <mfrac> <mn>1</mn> <mi>&pi;</mi> </mfrac> <msubsup> <mo>&Integral;</mo> <mrow> <mo>-</mo> <mi>&infin;</mi> </mrow> <mrow> <mo>+</mo> <mi>&infin;</mi> </mrow> </msubsup> <mfrac> <mrow> <mi>q</mi> <mrow> <mo>(</mo> <mi>&tau;</mi> <mo>)</mo> </mrow> </mrow> <mrow> <mi>t</mi> <mo>-</mo> <mi>&tau;</mi> </mrow> </mfrac> <mi>d</mi> <mi>&tau;</mi> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>20</mn> <mo>)</mo> </mrow> </mrow>

In formula, " H " represents Hilbert conversion,It is the time domain deamplification after conversion, when τ represents some of deamplification Carve；

After carrying out Hilbert conversion, the signal after conversion and original time domain deamplification can be merged, and obtain one group New signal Analysis Q (t), its expression formula are：

<mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>=</mo> <mi>q</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>+</mo> <mi>j</mi> <mover> <mi>q</mi> <mo>~</mo> </mover> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>21</mn> <mo>)</mo> </mrow> </mrow>

New signal Analysis Q (t) envelope A (t) and instantaneous phase ψ (t) can be expressed as

<mrow> <mi>A</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>=</mo> <msqrt> <mrow> <msup> <mi>q</mi> <mn>2</mn> </msup> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>+</mo> <msup> <mover> <mi>q</mi> <mo>~</mo> </mover> <mn>2</mn> </msup> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> </mrow> </msqrt> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>22</mn> <mo>)</mo> </mrow> </mrow>

<mrow> <mi>&psi;</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>=</mo> <mi>arctan</mi> <mo>&lsqb;</mo> <mover> <mi>q</mi> <mo>~</mo> </mover> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>/</mo> <mi>q</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>&rsqb;</mo> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>23</mn> <mo>)</mo> </mrow> </mrow>

Instantaneous phase ψ (t) is differentiated, then can obtain real-time frequency ω (t), i.e.,

ψ ' (t)=ω (t) (24)

Hilbert conversion is carried out to formula (19), following formula can be obtained：

<mrow> <mi>m</mi> <mover> <mover> <mi>q</mi> <mo>~</mo> </mover> <mo>&CenterDot;&CenterDot;</mo> </mover> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>+</mo> <mi>c</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mover> <mover> <mi>q</mi> <mo>~</mo> </mover> <mo>&CenterDot;</mo> </mover> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>+</mo> <mi>k</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mover> <mi>q</mi> <mo>~</mo> </mover> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>=</mo> <mn>0</mn> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>25</mn> <mo>)</mo> </mrow> </mrow>

When carrying out Hilbert conversion to formula (19), it is assumed that time-varying modal damping c (t) and time-varying rigidity k (t) is stable changes , i.e., in conversion process, c (t) and k (t) they are constant, i.e.,

<mrow> <mi>H</mi> <mo>&lsqb;</mo> <mi>c</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mover> <mi>q</mi> <mo>&CenterDot;</mo> </mover> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>&rsqb;</mo> <mo>=</mo> <mi>c</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mi>H</mi> <mo>&lsqb;</mo> <mover> <mi>q</mi> <mo>&CenterDot;</mo> </mover> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>&rsqb;</mo> <mo>=</mo> <mi>c</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mover> <mover> <mi>q</mi> <mo>~</mo> </mover> <mo>&CenterDot;</mo> </mover> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>26</mn> <mo>)</mo> </mrow> </mrow>

<mrow> <mi>H</mi> <mo>&lsqb;</mo> <mi>k</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mi>q</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>&rsqb;</mo> <mo>=</mo> <mi>k</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mi>H</mi> <mo>&lsqb;</mo> <mi>q</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>&rsqb;</mo> <mo>=</mo> <mi>k</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mover> <mi>q</mi> <mo>~</mo> </mover> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>27</mn> <mo>)</mo> </mrow> </mrow>

Formula (25) both ends are multiplied by into imaginary unit j to be added with formula (19), the equation of motion expressed with signal Analysis can be obtained, i.e.,

<mrow> <mi>m</mi> <mover> <mi>Q</mi> <mo>&CenterDot;&CenterDot;</mo> </mover> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>+</mo> <mi>c</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mover> <mi>Q</mi> <mo>&CenterDot;</mo> </mover> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>+</mo> <mi>k</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mi>Q</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>=</mo> <mn>0</mn> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>28</mn> <mo>)</mo> </mrow> </mrow>

, can be by the single order and second dervative of signal Analysis in formula (28) using formula (21) to formula (23)With envelope A (t) and Real-time frequency ω (t) is expressed, i.e.,

<mrow> <mover> <mi>Q</mi> <mo>&CenterDot;</mo> </mover> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>=</mo> <mi>Q</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>&lsqb;</mo> <mfrac> <mrow> <mover> <mi>A</mi> <mo>&CenterDot;</mo> </mover> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> </mrow> <mrow> <mi>A</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> </mrow> </mfrac> <mo>+</mo> <mi>j</mi> <mi>&omega;</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>&rsqb;</mo> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>29</mn> <mo>)</mo> </mrow> </mrow>

<mrow> <mover> <mi>Q</mi> <mo>&CenterDot;&CenterDot;</mo> </mover> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>=</mo> <mi>Q</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>&lsqb;</mo> <mfrac> <mrow> <mover> <mi>A</mi> <mo>&CenterDot;&CenterDot;</mo> </mover> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> </mrow> <mrow> <mi>A</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> </mrow> </mfrac> <mo>-</mo> <msup> <mi>&omega;</mi> <mn>2</mn> </msup> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>+</mo> <mn>2</mn> <mi>j</mi> <mfrac> <mrow> <mover> <mi>A</mi> <mo>&CenterDot;</mo> </mover> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mi>&omega;</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> </mrow> <mrow> <mi>A</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> </mrow> </mfrac> <mo>+</mo> <mi>j</mi> <mover> <mi>&omega;</mi> <mo>&CenterDot;</mo> </mover> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>&rsqb;</mo> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>30</mn> <mo>)</mo> </mrow> </mrow>

Formula (29) and formula (30) are updated to formula (28), can be obtained after arrangement

<mrow> <mi>m</mi> <mfrac> <mrow> <mover> <mi>A</mi> <mo>&CenterDot;&CenterDot;</mo> </mover> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> </mrow> <mrow> <mi>A</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> </mrow> </mfrac> <mo>-</mo> <msup> <mi>m&omega;</mi> <mn>2</mn> </msup> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>+</mo> <mi>k</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>+</mo> <mi>c</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mfrac> <mrow> <mover> <mi>A</mi> <mo>&CenterDot;</mo> </mover> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> </mrow> <mrow> <mi>A</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> </mrow> </mfrac> <mo>+</mo> <mi>j</mi> <mo>&lsqb;</mo> <mn>2</mn> <mi>m</mi> <mfrac> <mrow> <mover> <mi>A</mi> <mo>&CenterDot;</mo> </mover> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mi>&omega;</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> </mrow> <mrow> <mi>A</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> </mrow> </mfrac> <mo>+</mo> <mi>m</mi> <mover> <mi>&omega;</mi> <mo>&CenterDot;</mo> </mover> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>+</mo> <mi>c</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mi>&omega;</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>&rsqb;</mo> <mo>=</mo> <mn>0</mn> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>31</mn> <mo>)</mo> </mrow> </mrow>

The real and imaginary parts of formula (31) are made to be equal to zero, so that it may which obtain composite structural system has the non-linear firm of amplitude dependence Degree and the expression formula of damping

<mrow> <mi>k</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>=</mo> <mi>m</mi> <mo>&lsqb;</mo> <msup> <mi>&omega;</mi> <mn>2</mn> </msup> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>-</mo> <mfrac> <mrow> <mover> <mi>A</mi> <mo>&CenterDot;&CenterDot;</mo> </mover> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> </mrow> <mrow> <mi>A</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> </mrow> </mfrac> <mo>+</mo> <mn>2</mn> <mfrac> <mrow> <msup> <mover> <mi>A</mi> <mo>&CenterDot;</mo> </mover> <mn>2</mn> </msup> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> </mrow> <mrow> <msup> <mi>A</mi> <mn>2</mn> </msup> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> </mrow> </mfrac> <mo>+</mo> <mfrac> <mrow> <mover> <mi>&omega;</mi> <mo>&CenterDot;</mo> </mover> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> </mrow> <mrow> <mi>&omega;</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> </mrow> </mfrac> <mfrac> <mrow> <mover> <mi>A</mi> <mo>&CenterDot;</mo> </mover> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> </mrow> <mrow> <mi>A</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> </mrow> </mfrac> <mo>&rsqb;</mo> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>32</mn> <mo>)</mo> </mrow> </mrow>

<mrow> <mi>c</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>=</mo> <mo>-</mo> <mi>m</mi> <mo>&lsqb;</mo> <mn>2</mn> <mfrac> <mrow> <mover> <mi>A</mi> <mo>&CenterDot;</mo> </mover> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> </mrow> <mrow> <mi>A</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> </mrow> </mfrac> <mo>+</mo> <mfrac> <mrow> <mover> <mi>&omega;</mi> <mo>&CenterDot;</mo> </mover> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> </mrow> <mrow> <mi>&omega;</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> </mrow> </mfrac> <mo>&rsqb;</mo> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>33</mn> <mo>)</mo> </mrow> </mrow>

Step 4-6-3：After each rank time domain deamplification for obtaining composite plate, Hilbert conversion process is carried out to it respectively, enters one Step obtains the envelope A (t) and real-time frequency ω (t) of each rank time domain deamplification using formula (22) and formula (24), then will It is brought into formula (33), then can obtain the time-varying damping parameter c (t) of tested composite plate；

<mrow> <mi>&zeta;</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>=</mo> <mfrac> <mrow> <mi>c</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> </mrow> <mrow> <mn>2</mn> <mi>m</mi> <mi>&omega;</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> </mrow> </mfrac> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>34</mn> <mo>)</mo> </mrow> </mrow>

According to above formula, it is converted as conventional damping ratios ζ (t).
The fiber composite plate nonlinear kinetics parameter test system under environment 10. a kind of heat is shaken, it is characterised in that including：

Enter the vibration module of row energization to composite plate using each rank intrinsic frequency of fiber composite plate as driving frequency, for multiple Plywood is scanned to obtain the laser scanning vibration measuring module of vibratory response data, for vibratory response data are handled with The Data Management Analysis module of nonlinear kinetics parameter is tested, for controlling the hot ring of test environment temperature according to test request Border analog module；

The thermal environment simulation module includes：Using heat insulating box made of high-temperature resistant thermal insulating material, the top of the heat insulating box Face and front, which are provided with, uses observation window made of high temperature resistance optical glass, and carbon fiber heating tube, hot box are provided with heat insulating box Internal both sides are provided with fan, and heat insulating box inner upper corner is respectively equipped with thermocouple, heat insulating box bottom opening, passes through spiral shell Nail is connected with heat insulation pedestal；

The fiber composite plate is fixed on by installs fixture on the mounting platform of the vibration module, and the mounting platform passes through The heat insulating box bottom opening is stretched into inside the heat insulating box, and mounting platform and heat insulation pedestal are realized by flexible glue bar and sealed Connection；

The laser scanning vibration measuring module is arranged on the top of the heat insulating box, and the laser passes through the high temperature resistance during test Optical glass is scanned to the fiber composite plate.