CN106370726A - Damage detection system for two-dimensional composite material and detection method thereof - Google Patents

Abstract

A damage detection system for a two-dimensional composite material and a detection method thereof. The damage detection system includes a measurement apparatus for measuring modal shape of the two-dimensional composite material, a Fourier modal curvature calculation module, and a determination module. The modal shape measurement apparatus includes a force hammer, which is used for knocking measuring points that are uniformly distributed on the two-dimensional composite material at an interval h, an acceleration sensor, which is used for measuring the acceleration of the measuring points, and a modal shape measuring module. The modal shape measuring module, which is connected to the acceleration sensor, generates a modal shape (w(x, y)) on the basis of the acceleration, wherein x and y refers to plane coordinate value of the measuring point. The Fourier modal curvature calculation module calculates Fourier modal curvature through a formula. The determination module is connected to the Fourier modal curvature calculation module.

Description

A kind of damage detection system of Two-dimensional Composites and its detection method

Technical field

The invention belongs to NDT of composite field, the damage check system of more particularly to a kind of Two-dimensional Composites System and its detection method.

Background technology

Composite has a wide range of applications in wind-driven generator, aircraft blade, aero-engine, and damages occurred frequently, Therefore quick damage check is carried out to it and seem particularly significant.Traditional Dynamic Non-Destruction Measurement is all difficult to full to varying degrees The requirement of online, in place and institute's damage check versatility in the detection of sufficient engineering structure damage, such as magnetic powder inspection method can only be suitable for In the surface damage detection of ferrimagnet, fluorescent penetrating inspection method only can be suitably used for structural member surface crack detection, and need to be in spy Recognized in different photoenvironment, x-ray testing equipment is expensive, hazards of electromagnetic radiation health, and ultrasound detection is to working surface Require strict, defect is disclosed and lacks intuitive, be unsuitable for the detection of surface defect, therefore above method is all difficult to realize arbitrarily Material surface, the damage monitoring in place online of internal injury.And on the other hand, structure running exists vibration in a large number Signal, displacement, speed, acceleration, dynamic stress and strain etc., test and analysis for these signals tend not to affect To operating or the station of structure, carry out Structural Dynamicses Non-Destructive Testing hence with vibration signal and there is definite meaning.

At present, both at home and abroad the research of the kinetics Dynamic Non-Destruction Measurement of general structure is concentrated mainly on founding mathematical models, The aspects such as dynamic analyses, its implementation is predominantly made the difference with the early stage health vibration shape using current structural eigenvector and obtains vibration shape change Change, then pass through vibration shape intensity of variation and change occurs location determination crackle to occur.Due to the use of structural health data, affect The real-time of these methods and high efficiency, therefore to the Structural Dynamicses solving no reference data contrast in Practical Project no Damage in detection and seem helpless.

Patent documentation cn103592365 discloses a kind of rapid rotor crack detection method and comprises the following steps: (1) utilizes To rotor, the displacement under different rotating speeds running status carries out pointwise test to noncontacting proximity sensor, obtains the rotor position of each measuring point Move data, connect into curve, become the operation response vibration shape；(2) centered difference is carried out to operation response vibration shape d, calculate rotor Curvature mode shape w, wherein, the curvature mode shape wi of measuring point i is expressed as: wi=di+1-2di+di-1h2--- (1), wherein footmark i table Show that measuring point is numbered, h represents the physical distance between adjacent measuring point, and di represents the vibration shape amplitude of measuring point i；(3) calculate curvature mode shape Waveform dimension, forms curvature dimension curve, i.e. curvature dimension crackle indicative curve；(4) analyze curvature dimension crackle indicative curve Peak value, according to the magnitude relationship between peak-peak, minimum peak and secondary peak value, judge that rotor whether there is crackle, and Crackle is positioned.This patent carries out crack detection to rotor by the current measurement mode vibration shape, and this patent documentation is also The invention achievement of the applicant's early stage, but this patent need to improve further, and the curvature mode shape noise that this patent obtains is big, essence Exactness is also to be hoisted, needs acquisition Mode Shape and Mode Shape curvature to be optimized further, in addition, this patent cannot be to two The composite of dimension carries out accurate fault localization.

Disclosed in patent documentation cn104567762, a kind of engineering machinery arm support on-line monitoring method includes: receives arm support The tangent line of the radius of curvature of multiple discrete points and discrete point place circular arc angle with respect to the horizontal plane in each joint arm；Root Tangent line angle with respect to the horizontal plane according to the radius of curvature of the plurality of discrete point and one discrete point place circular arc The shape of monitoring arm support.This patent achieves shape that is quick and monitoring arm support in real time, but this patent cannot be carried out no in real time Damage detection it is impossible to quickly identify the damage position of composite, the composite being not suitable for on-the-spot guidance two dimension is carried out accurately Fault localization.

Patent documentation cn105424350 discloses and a kind of includes thin-walled based on the thin-wall part mould measurement system of machine vision Part, ccd industrial camera, common LED light source, vibrator, vibrator control device, Computer Image Processing device；Thin-wall part One end is fixed on the excitation head below vibrator, and the other end is in free vacant state, sets on the side surface of thin-wall part Put reflection plaster；Vibrator is suspended on fixed support, and ccd industrial camera spider is horizontally fixed on the dead ahead of device, ccd The outfan of industrial camera is connected with the input of Computer Image Processing device, the outfan of Computer Image Processing device with Vibrator control device is connected, and common LED light source is arranged on the left front of video camera；The outfan of vibrator control device and work( The input of rate amplifier is connected, and the outfan of power amplifier is connected with the excitation head of vibrator, and excitation head end is installed and added Velocity sensor, the outfan of acceleration transducer is connected with vibrator control device.This patent is followed the tracks of anti-in thin-walled beam Light pastes the displacement of characteristic point, can get the vibration information of multiple spot on thin-wall part, and the vibration information of multiple spot can be synchronized point Analysis, and then can get the vibration shape under natural frequency and natural frequency, but this patent needs to follow the tracks of reflection plaster, limits application model Enclose, and only Non-Destructive Testing be cannot be carried out by the vibration shape it is impossible to quickly identify the damage position of composite, in addition, this patent is no Method carries out accurate fault localization to two-dimentional composite.

Therefore, urgency technical issues that need to address in this area are that providing one kind to have counts variable to Two-dimensional Composites Property is little, noise immunity is strong, certainty of measurement is high, can quickly identify the damage position of composite two-dimensional structure, has computing Implementation is good, simple, the composite detection system of suitable on-the-spot guidance composite two-dimensional structure damage check.

In the background section disclosed above- mentioned information be used only for strengthening to the understanding of background of the present invention it is thus possible to The information of prior art known to a person of ordinary skill in the art in comprising not constitute home.

Content of the invention

The Non-Destructive Testing that the present invention is directed to the composite of two dimension provides a kind of detecting system, and it is by obtaining many order modes The state vibration shape, then carries out curvature estimation and Fourier transformation, optimizes Detection results, filtered detection noise, improve measurement Precision, and simple.

The purpose of the present invention is to be achieved by the following technical programs.

According to an aspect of the present invention, a kind of damage detection system of Two-dimensional Composites includes measuring elongate composite The measurement apparatus of Mode Shape, Fourier mode curvature estimation module and judge module, described Mode Shape measurement apparatus include For tapping the power hammer that the equally distributed measurement point of h is spaced on described elongate composite, the acceleration measuring described measurement point Acceleration transducer and Mode Shape measurement module, connect described acceleration transducer described Mode Shape measurement module Mode Shape is generated based on described acceleration, described Fourier mode curvature estimation module is calculated Fourier modulus by formula State curvature,Wherein,

$\frac{{\∂}^2{w}_{x,y}}{\∂x^2}=-\frac{h}{2\mathrm{\π}}\underset{k_x}{\σ}{k}_x^2{e}^{{\mathrm{ik}}_{x}x}{\hat{w}}_{k_x,y},$

$\frac{{\∂}^2{w}_{x,y}}{\∂y^2}=-\frac{h}{2\mathrm{\π}}\underset{k_y}{\σ}{k}_y^2{e}^{{\mathrm{ik}}_{y}y}{\hat{w}}_{x,k_y},$

${\hat{w}}_{k_x,y}=\underset{x}{\σ}{e}^{-{\mathrm{ik}}_{x}x}{w}_{x,y},$

${\hat{w}}_{x,k_y}=\underset{y}{\σ}{e}^{-{\mathrm{ik}}_{y}y}{w}_{x,y}---\left(f1\right),$

Wherein, h represents described measurement dot spacing, and kx, ky are expressed as the inverse of measurement point x, y-coordinate value, and e represents that nature is normal Number, w (x, y) represents measured Mode Shape, and described judge module connects described Fourier mode curvature estimation module, if Described Fourier modal curvature is more than predetermined threshold, and described judge module judges that described Fourier modal curvature is more than predetermined threshold Measurement point be damage position.

Two-dimensional Composites in the present invention are the composites of planar structure or plate shell class.

Preferably, described predetermined threshold is the given threshold value of 3 σ criterions.

Preferably, the damage detection system of described Two-dimensional Composites also includes graphics module, and described graphics module connects Described Mode Shape measurement module and drafting Mode Shape curve, described graphics module connects described Fourier mode curvature estimation Module and drafting Fourier mode curvature curve.

Described judge module is provided with 3 σ threshold filtering modules, and described Fourier mode curvature curve is via 3 σ threshold filtering moulds Graphics module is sent after block filtration treatment.

Preferably, described Mode Shape curve is 1-4 order mode state mode curve.

Preferably, described measurement point is that interval h equally distributed 8 is multiplied by n measurement point, and wherein n is the rank of Mode Shape Number.

Preferably, described Fourier mode curvature estimation module includes computing unit and Fourier transformation unit.

Preferably, described Mode Shape measurement module is model analyses equipment, and described judge module is Digital Signal Processing Device.

According to a further aspect in the invention, a kind of detection side of the damage detection system using described Two-dimensional Composites Method comprises the following steps.

In first step, described power hammer taps and is spaced the equally distributed measurement point of h, acceleration in described elongate composite Sensor measures the acceleration of described measurement point, and described Mode Shape measurement module is based on described acceleration and generates Mode Shape.

In second step, it is bent that described Fourier mode curvature estimation module is calculated Fourier mode by formula (f1) Rate,Wherein,

$\frac{{\∂}^2{w}_{x,y}}{\∂x^2}=-\frac{h}{2\mathrm{\π}}\underset{k_x}{\σ}{k}_x^2{e}^{{\mathrm{ik}}_{x}x}{\hat{w}}_{k_x,y},$

$\frac{{\∂}^2{w}_{x,y}}{\∂y^2}=-\frac{h}{2\mathrm{\π}}\underset{k_y}{\σ}{k}_y^2{e}^{{\mathrm{ik}}_{y}y}{\hat{w}}_{x,k_y},$

${\hat{w}}_{k_x,y}=\underset{x}{\σ}{e}^{-{\mathrm{ik}}_{x}x}{w}_{x,y},$

${\hat{w}}_{x,k_y}=\underset{y}{\σ}{e}^{-{\mathrm{ik}}_{y}y}{w}_{x,y}---\left(f1\right),$

Wherein, h represents described measurement dot spacing, and kx, ky are expressed as the inverse of measurement point x, y-coordinate value, and e represents that nature is normal Number, w (x, y) represents measured Mode Shape.

In third step, described judge module connects described Fourier mode curvature estimation module, if described Fourier Modal curvature be more than predetermined threshold, described judge module judges described Fourier modal curvature more than predetermined threshold measurement point as Damage position.

Described above is only the general introduction of technical solution of the present invention, and the technological means in order to make the present invention are clearer Understand, reach the degree that those skilled in the art can be practiced according to the content of description, and in order to allow the present invention Above and other objects, features and advantages can become apparent, illustrated with the specific embodiment of the present invention below Explanation.

Brief description

By detailed description, the various other advantage of the present invention and benefit in reading hereafter preferred embodiment Those of ordinary skill in the art be will be clear from understanding.Figure of description is only used for illustrating the purpose of preferred implementation, And it is not considered as limitation of the present invention.It should be evident that drawings discussed below is only some embodiments of the present invention, For those of ordinary skill in the art, on the premise of not paying creative work, can also obtain according to these accompanying drawings Other accompanying drawings.And in whole accompanying drawing, it is presented with like reference characters identical part.

In the accompanying drawings:

Fig. 1 is the structural representation of the damage detection system of Two-dimensional Composites according to an embodiment of the invention；

Fig. 2 is the structural representation of the damage detection system of Two-dimensional Composites in accordance with another embodiment of the present invention；

Fig. 3 is the schematic diagram that damages for slender type of damage of Two-dimensional Composites according to an embodiment of the invention；

Fig. 4 is the connection Fourier mode of the damage detection system of Two-dimensional Composites according to an embodiment of the invention The Fourier mode curvature curve schematic diagram that the graphics module of curvature estimation module is drawn on the material of Fig. 3；

Fig. 5 is the connection Fourier mode of the damage detection system of Two-dimensional Composites according to an embodiment of the invention The damage range schematic diagram that the graphics module of curvature estimation module is drawn based on Fig. 4；

Fig. 6 is the schematic diagram for bulky lesion for the damage of Two-dimensional Composites according to an embodiment of the invention；

Fig. 7 is the connection Fourier mode of the damage detection system of Two-dimensional Composites according to an embodiment of the invention The Fourier mode curvature curve schematic diagram that the graphics module of curvature estimation module is drawn on the material of Fig. 5；

Fig. 8 is the connection Fourier mode of the damage detection system of Two-dimensional Composites according to an embodiment of the invention The damage range schematic diagram that the graphics module of curvature estimation module is drawn based on Fig. 7；

Fig. 9 be Two-dimensional Composites according to an embodiment of the invention damage be multiple damages schematic diagram；

Figure 10 is the connection Fourier modulus of the damage detection system of Two-dimensional Composites according to an embodiment of the invention The Fourier mode curvature curve schematic diagram that the graphics module of state curvature estimation module is drawn on the material of Fig. 7；

Figure 11 is the connection Fourier modulus of the damage detection system of Two-dimensional Composites according to an embodiment of the invention The damage range schematic diagram that the graphics module of state curvature estimation module is drawn based on Figure 10；

Figure 12 is the damage check of the damage detection system of use Two-dimensional Composites according to an embodiment of the invention The step schematic diagram of method.

Below in conjunction with drawings and Examples, the present invention is further explained.

Specific embodiment

It is more fully described the specific embodiment of the present invention below with reference to accompanying drawings.Although showing the present invention's in accompanying drawing Specific embodiment is it being understood, however, that may be realized in various forms the present invention and should not being limited by embodiments set forth here System.On the contrary, these embodiments are provided to be able to be best understood from the present invention, and can be complete by the scope of the present invention Convey to those skilled in the art.

It should be noted that employing some vocabulary in the middle of description and claim to censure specific components.Ability Field technique personnel it would be appreciated that, technical staff may call same assembly with different nouns.This specification and right Require not in the way of the difference of noun is used as distinguishing assembly, but difference functionally is used as differentiation with assembly Criterion.If mentioned "comprising" in the middle of description in the whole text and claim or " inclusion " are an open language, therefore should solve It is interpreted into " comprise but be not limited to ".Description subsequent descriptions be implement the present invention better embodiment, so described description be with For the purpose of the rule of description, it is not limited to the scope of the present invention.Protection scope of the present invention is when regarding appended right Defined person is required to be defined.

For ease of the understanding to the embodiment of the present invention, do further below in conjunction with accompanying drawing taking several specific embodiments as a example Explanation, and each accompanying drawing does not constitute the restriction to the embodiment of the present invention.

Fig. 1 is the structural representation of the damage detection system of Two-dimensional Composites of one embodiment of the present of invention, this Bright embodiment will be specifically described in conjunction with Fig. 1.

As shown in figure 1, An embodiment provides a kind of damage detection system of Two-dimensional Composites, two dimension The damage detection system of composite includes measurement apparatus (1), the Fourier mode song measuring Two-dimensional Composites Mode Shape Rate computing module (2) and judge module (3), described Mode Shape measurement apparatus (1) are included for tapping described two dimension composite wood On material be spaced the equally distributed measurement point of h power hammer (4), measure described measurement point acceleration acceleration transducer (5) with And Mode Shape measurement module (6), the described Mode Shape measurement module (6) connecting described acceleration transducer (5) is based on institute State acceleration and generate Mode Shape (w (x, y)), wherein x, y represent the plane coordinate value of measurement point, described Fourier modal curvature Computing module (2) is calculated Fourier modal curvature (w " (x, y)) by formula (f1),

$w^{\′\′}(x,y)=\frac{{\∂}^{2}w(x,y)}{\∂x^2}+\frac{{\∂}^{2}w(x,y)}{\∂y^2},$

Wherein,

$\frac{{\∂}^2{w}_{x,y}}{\∂x^2}=-\frac{h}{2\mathrm{\π}}\underset{k_x}{\σ}{k}_x^2{e}^{{\mathrm{ik}}_{x}x}{\hat{w}}_{k_x,y},$

$\frac{{\∂}^2{w}_{x,y}}{\∂y^2}=-\frac{h}{2\mathrm{\π}}\underset{k_y}{\σ}{k}_y^2{e}^{{\mathrm{ik}}_{y}y}{\hat{w}}_{x,k_y},$

${\hat{w}}_{k_x,y}=\underset{x}{\σ}{e}^{-{\mathrm{ik}}_{x}x}{w}_{x,y},$

${\hat{w}}_{x,k_y}=\underset{y}{\σ}{e}^{-{\mathrm{ik}}_{y}y}{w}_{x,y}---\left(f1\right),$

Wherein, h represents described measurement dot spacing, and kx, ky are expressed as the inverse of measurement point x, y-coordinate value, and e represents that nature is normal Number, w (x, y) represents measured Mode Shape,

Described judge module (3) connects described Fourier mode curvature estimation module (2), if described Fourier mode is bent Rate (w " (x, y)) is more than predetermined threshold, and described judge module (3) judges described Fourier modal curvature (w " (x, y)) more than pre- The measurement point determining threshold value is damage position.

Two-dimensional Composites in the present invention can be the composite of plate shell class.

In one embodiment, described predetermined threshold is the given threshold value of 3 σ criterions.

In one embodiment, described measurement point is multiplied by 8 for interval h equally distributed 8 and is multiplied by n measurement point, and wherein n is The exponent number of Mode Shape.

In one embodiment, described Fourier mode curvature estimation module 2 includes computing unit and Fourier transform list Unit.

In one embodiment, described Mode Shape measurement module 6 is model analyses equipment, and described judge module 3 is number Word signal processor.

In embodiments of the present invention preferably, judge module 3 can be general processor, digital signal processor, special Integrated circuit asic, field programmable gate array fpga, analog circuit, digital circuit, and combinations thereof or other known to or after The processor of exploitation.Further, judge module 3 includes memorizer, and memorizer can be volatile memory or non-volatile Memorizer, memorizer can include one or more read only memory rom, random access memory ram, flash memory, electricity Sub- Erasable Programmable Read Only Memory EPROM eeprom or other types of memorizer.

In one embodiment, composite is elongated 24 layer gfrp composite (glass-fiber reinforced Plastic), a size of square of 250mm × 250mm.Using by 5,1 power hammer of 1 acceleration transducer 4 and such as domestic hundred million The measurement apparatus 1 measurement mode vibration shape of the Mode Shape that the Mode Shape measurement module 6 that permanent number is adopted is formed, in composite wood to be measured In material structure, the measure-point amount selection principle according to 8 × 8 × n, such as considers the first-order modal vibration shape, therefore chooses measuring point number and be 64, It is uniformly arranged some measuring points, can be with leftmost measurement point as zero, numerical value on horizontal x-axis direction for each measurement point For x value, the numerical value on vertical y-axis direction is y value, and acceleration transducer 5 position is fixed therein any one point position, And keep constant in whole measurement process.Tap using to measuring point one by one, obtain structure first-order modal vibration shape w (x, y).Described Fourier mode curvature estimation module 2 is calculated Fourier modal curvature by formula f1Wherein,

$\frac{{\∂}^2{w}_{x,y}}{\∂x^2}=-\frac{k}{2\mathrm{\π}}\underset{k_x}{\σ}{k}_x^2{e}^{{\mathrm{ik}}_{x}x}{\hat{w}}_{k_x,y},$

$\frac{{\∂}^2{w}_{x,y}}{\∂y^2}=-\frac{h}{2\mathrm{\π}}\underset{k_y}{\σ}{k}_y^2{e}^{{\mathrm{ik}}_{y}y}{\hat{w}}_{x,k_y},$

${\hat{w}}_{k_x,y}=\underset{x}{\σ}{e}^{-{\mathrm{ik}}_{x}x}{w}_{x,y},$

${\hat{w}}_{x,k_y}=\underset{y}{\σ}{e}^{-{\mathrm{ik}}_{y}y}{w}_{x,y}---\left(f1\right),$

Wherein, h represents described measurement dot spacing, and kx, ky are expressed as the inverse of measurement point x, y-coordinate value, and e represents that nature is normal Number, w (x, y) represents measured Mode Shape.

If judge module 3 judges the point having more than 3 σ method institute given threshold values, assert there is abnormal data at this, recognize It is set to damage；Otherwise, object construction is judged to health.

Fig. 2 is the structural representation of the damage detection system of Two-dimensional Composites of one embodiment of the present of invention, this Bright embodiment will be specifically described in conjunction with Fig. 2.

As shown in Fig. 2 An embodiment provides a kind of damage detection system of Two-dimensional Composites, two dimension The damage detection system of composite includes measurement apparatus 1, the Fourier modal curvature measuring elongate composite Mode Shape Computing module 2, judge module 3 and graphics module 7, described Mode Shape measurement apparatus 1 are included for tapping described elongated composite On material be spaced the equally distributed measurement point of h power hammer 4, measure described measurement point the acceleration transducer 5 of acceleration and Mode Shape measurement module 6, the described Mode Shape measurement module 6 connecting described acceleration transducer 5 is based on described acceleration Generate Mode Shape w (x, y), it is bent that described Fourier mode curvature estimation module 2 is calculated Fourier mode by formula f1 RateWherein,

$\frac{{\∂}^2{w}_{x,y}}{\∂x^2}=-\frac{h}{2\mathrm{\π}}\underset{k_x}{\σ}{k}_x^2{e}^{{\mathrm{ik}}_{x}x}{\hat{w}}_{k_x,y},$

$\frac{{\∂}^2{w}_{x,y}}{\∂y^2}=-\frac{h}{2\mathrm{\π}}\underset{k_y}{\σ}{k}_y^2{e}^{{\mathrm{ik}}_{y}y}{\hat{w}}_{x,k_y},$

${\hat{w}}_{k_x,y}=\underset{x}{\σ}{e}^{-{\mathrm{ik}}_{x}x}{w}_{x,y},$

${\hat{w}}_{x,k_y}=\underset{y}{\σ}{e}^{-{\mathrm{ik}}_{y}y}{w}_{x,y}---\left(f1\right),$

Wherein, h represents described measurement dot spacing, and kx, ky are expressed as the inverse of measurement point x, y-coordinate value, and e represents that nature is normal Number, w (x, y) represents measured Mode Shape.Described graphics module 7 connects described Mode Shape measurement module 6 and draws mould State mode curve, described graphics module 7 connects described Fourier mode curvature estimation module 2 and draws Fourier modal curvature song Line, described judge module 3 connects described Fourier mode curvature estimation module 2, if described Fourier modal curvature is more than in advance Determine threshold value, described judge module 3 judges that described Fourier modal curvature is more than the measurement point of predetermined threshold as damage position.

In one embodiment, described Mode Shape curve is 1-4 order mode state mode curve.

Described judge module 3 is provided with 3 σ threshold filtering modules, and described Fourier mode curvature curve 7 is via 3 σ threshold filtering Modular filtration sends graphics module 7 after processing.

In one embodiment, as shown in Figure 3, composite is elongated 24 layer gfrp composite, a size of 250mm × 250mm, there is elongated vertical bar at and damages in this structure at 100mm.Using by 5,1 power hammer 4 of 1 acceleration transducer And the measurement apparatus 1 measurement mode vibration shape of the Mode Shape being formed as Mode Shape measurement module 6 that domestic hundred million permanent numbers are adopted, Measure-point amount selection principle according to 8 × 8 × n on composite structure to be measured, the present embodiment adopts the first-order modal vibration shape, therefore choosing Take measuring point number to be 64, be uniformly arranged some measuring points, can be with leftmost starting point as zero, each measurement point is in horizontal x Numerical value on direction of principal axis is x value, and the numerical value on vertical y-axis direction is y value, and acceleration transducer 5 position is fixed therein Any one point position, and keep constant in whole measurement process.Tap using to measuring point one by one, obtain the one of structure Rank Mode Shape.

Described Fourier mode curvature estimation module 2 is calculated Fourier modal curvature by formula f1Wherein,

$\frac{{\∂}^2{w}_{x,y}}{\∂x^2}=-\frac{h}{2\mathrm{\π}}\underset{k_x}{\σ}{k}_x^2{e}^{{\mathrm{ik}}_{x}x}{\hat{w}}_{k_x,y},$

$\frac{{\∂}^2{w}_{x,y}}{\∂y^2}=-\frac{h}{2\mathrm{\π}}\underset{k_y}{\σ}{k}_y^2{e}^{{\mathrm{ik}}_{y}y}{\hat{w}}_{x,k_y},$

${\hat{w}}_{k_x,y}=\underset{x}{\σ}{e}^{-{\mathrm{ik}}_{x}x}{w}_{x,y},$

${\hat{w}}_{x,k_y}=\underset{y}{\σ}{e}^{-{\mathrm{ik}}_{y}y}{w}_{x,y}---\left(f1\right),$

Wherein, h represents described measurement dot spacing, and kx, ky are expressed as the inverse of measurement point x, y-coordinate value, and e represents that nature is normal Number, w (x, y) represents measured Mode Shape, obtain 1 first order mode is brought into Fourier mode curvature estimation formula f1 respectively and obtains Arrive Fourier mode curvature curve.As shown in figure 4, graphics module 7 depicts calculating based on the first-order modal vibration shape Rank Fourier mode curvature curve.If judge module 3 judges the point having more than 3 σ method institute given threshold values, assert and deposit at this In abnormal data, regard as damaging；Otherwise, object construction is judged to health.As shown in figure 5, described judge module 3 is provided with 3 σ thresholds Value filtering module, described Fourier mode curvature curve 7 sends graphics module 7 after processing via 3 σ threshold filtering modular filtration, Show in Figure 5 at substantially 100mm beyond 3 σ method institute given threshold values, that is, judge to exist at 100mm to damage.It can be seen that, this Bright identified damage position is substantially identical with actual damage position.

In another embodiment, the block degree of impairment of detection, for example, as shown in Figure 6, composite is elongated 24 layer Gfrp composite, a size of 250mm × 250mm, there is the square damage of the 50mm length of side in this structure at 50mm.Profit With by 5,1 power of 1 acceleration transducer hammer 4 and the mode that formed as Mode Shape measurement module 6 that domestic hundred million perseverance numbers are adopted The measurement apparatus 1 measurement mode vibration shape of the vibration shape, on composite structure to be measured, the measure-point amount selection according to 8 × 8 × n is former Then, the present embodiment adopts the first-order modal vibration shape, therefore chooses measuring point number and be 64, is uniformly arranged some measuring points, can be with Far Left Starting point be zero, numerical value on horizontal x-axis direction for each measurement point be x value, the numerical value on vertical y-axis direction be y Value, acceleration transducer 5 position is fixed therein any one point position, and keeps constant in whole measurement process.Make With tapping to measuring point one by one, obtain the first-order modal vibration shape of structure.

Described Fourier mode curvature estimation module 2 is calculated Fourier modal curvature by formula f1Wherein,

$\frac{{\∂}^2{w}_{x,y}}{\∂x^2}=-\frac{h}{2\mathrm{\π}}\underset{k_x}{\σ}{k}_x^2{e}^{{\mathrm{ik}}_{x}x}{\hat{w}}_{k_x,y},$

$\frac{{\∂}^2{w}_{x,y}}{\∂y^2}=-\frac{h}{2\mathrm{\π}}\underset{k_y}{\σ}{k}_y^2{e}^{{\mathrm{ik}}_{y}y}{\hat{w}}_{x,k_y},$

${\hat{w}}_{k_x,y}=\underset{x}{\σ}{e}^{-{\mathrm{ik}}_{x}x}{w}_{x,y},$

${\hat{w}}_{x,k_y}=\underset{y}{\σ}{e}^{-{\mathrm{ik}}_{y}y}{w}_{x,y}---\left(f1\right),$

Wherein, h represents described measurement dot spacing, and kx, ky are expressed as the inverse of measurement point x, y-coordinate value, and e represents that nature is normal Number, w (x, y) represents measured Mode Shape, obtain 1 first order mode is brought into Fourier mode curvature estimation formula f1 respectively and obtains Arrive Fourier mode curvature curve.As shown in fig. 7, graphics module 7 depicts calculating based on the first-order modal vibration shape Rank Fourier mode curvature curve.If judge module 3 judges the point having more than 3 σ method institute given threshold values, assert and deposit at this In abnormal data, regard as damaging；Otherwise, object construction is judged to health.As shown in figure 8, described judge module 3 is provided with 3 σ thresholds Value filtering module, described Fourier mode curvature curve 7 sends graphics module 7 after processing via 3 σ threshold filtering modular filtration, Show in fig. 8 at x direction and the substantially 50mm in y direction beyond 3 σ method institute given threshold values, that is, judge to exist at 50mm to damage Wound.It can be seen that, the damage position that the present invention is identified is substantially identical with actual damage position.

In another embodiment, there are multiple degree of impairments in detection, for example, as shown in Figure 9, composite is elongated 24 Layer gfrp composite, a size of 250mm × 250mm, there is panels with multiple site damage in this structure.Using by 1 acceleration transducer 5,1 Power hammer 4 and measurement apparatus 1 measurement mode of the Mode Shape being formed as Mode Shape measurement module 6 that domestic hundred million perseverance numbers are adopted The vibration shape, the measure-point amount selection principle according to 8 × 8 × n on composite structure to be measured, the present embodiment is shaken using first-order modal Type, therefore choose measuring point number and be 64, it is uniformly arranged some measuring points, can be with leftmost starting point as zero, each measurement point Numerical value on horizontal x-axis direction is x value, and the numerical value on vertical y-axis direction is y value, and acceleration transducer 5 position is fixed Any one point position wherein, and keep constant in whole measurement process.Tap using to measuring point one by one, tied The first-order modal vibration shape of structure.

Described Fourier mode curvature estimation module 2 is calculated Fourier modal curvature by formula f1Wherein,

$\frac{{\∂}^2{w}_{x,y}}{\∂x^2}=-\frac{h}{2\mathrm{\π}}\underset{k_x}{\σ}{k}_x^2{e}^{{\mathrm{ik}}_{x}x}{\hat{w}}_{k_x,y},$

$\frac{{\∂}^2{w}_{x,y}}{\∂y^2}=-\frac{h}{2\mathrm{\π}}\underset{k_y}{\σ}{k}_y^2{e}^{{\mathrm{ik}}_{y}y}{\hat{w}}_{x,k_y},$

${\hat{w}}_{k_x,y}=\underset{x}{\σ}{e}^{-{\mathrm{ik}}_{x}x}{w}_{x,y},$

${\hat{w}}_{x,k_y}=\underset{y}{\σ}{e}^{-{\mathrm{ik}}_{y}y}{w}_{x,y}---\left(f1\right),$

Wherein, h represents described measurement dot spacing, and kx, ky are expressed as the inverse of measurement point x, y-coordinate value, and e represents that nature is normal Number, w (x, y) represents measured Mode Shape, obtain 1 first order mode is brought into Fourier mode curvature estimation formula f1 respectively and obtains Arrive Fourier mode curvature curve.As shown in Figure 10, graphics module 7 depicts calculating based on the first-order modal vibration shape Rank Fourier mode curvature curve.If judge module 3 judges the point having more than 3 σ method institute given threshold values, assert and deposit at this In abnormal data, regard as damaging；Otherwise, object construction is judged to health.As shown in figure 11, described judge module 3 is provided with 3 σ Threshold filtering module, described Fourier mode curvature curve 7 sends graphics module after processing via 3 σ threshold filtering modular filtration 7, display 3 in fig. 11 everywhere beyond 3 σ method institute given threshold values, that is, judges to exist at 3 and damages.It can be seen that, the present invention is identified Damage position substantially identical with actual damage position.

Referring to Figure 12, the damage detection system using described Two-dimensional Composites according to an embodiment of the invention Damage detecting method comprises the following steps.

In first step s1, described power hammer 4 taps and is spaced the equally distributed measurement point of h in described elongate composite, plus Velocity sensor 5 measures the acceleration of described measurement point, and described Mode Shape measurement module 6 is based on described acceleration and generates mode Vibration shape w (x, y).

In second step s2, described Fourier mode curvature estimation module 2 is calculated Fourier mode by formula f1 Curvature,Wherein,

$\frac{{\∂}^2{w}_{x,y}}{\∂x^2}=-\frac{h}{2\mathrm{\π}}\underset{k_x}{\σ}{k}_x^2{e}^{{\mathrm{ik}}_{x}x}{\hat{w}}_{k_x,y},$

$\frac{{\∂}^2{w}_{x,y}}{\∂y^2}=-\frac{h}{2\mathrm{\π}}\underset{k_y}{\σ}{k}_y^2{e}^{{\mathrm{ik}}_{y}y}{\hat{w}}_{x,k_y},$

${\hat{w}}_{k_x,y}=\underset{x}{\σ}{e}^{-{\mathrm{ik}}_{x}x}{w}_{x,y},$

${\hat{w}}_{x,k_y}=\underset{y}{\σ}{e}^{-{\mathrm{ik}}_{y}y}{w}_{x,y}---\left(f1\right),$

Wherein, h represents described measurement dot spacing, and kx, ky are expressed as the inverse of measurement point x, y-coordinate value, and e represents that nature is normal Number, w (x, y) represents measured Mode Shape；

In third step s3, described judge module 3 connects described Fourier mode curvature estimation module 2, if described Fu Vertical leaf modal curvature w " (x, y) is more than predetermined threshold, and described judge module 3 judges described Fourier modal curvature w " (x, y) big In predetermined threshold measurement point be damage position.

In one embodiment, described predetermined threshold is the given threshold value of 3 σ criterions.

In one embodiment, in the second step, graphics module 7 connects described Mode Shape measurement module 6 and draws Mode Shape curve, described graphics module 7 connects described Fourier mode curvature estimation module 2 and draws Fourier modal curvature Curve.

Although being described to embodiment of the present invention above in association with accompanying drawing, the invention is not limited in above-mentioned Specific embodiments and applications field, above-mentioned specific embodiments are only schematic, guiding, rather than restricted 's.Those of ordinary skill in the art is under the enlightenment of this specification with the scope protected without departing from the claims in the present invention In the case of, the form of many kinds can also be made, these belong to the row of present invention protection.

Claims (10)

1. a kind of damage detection system of Two-dimensional Composites, it includes measuring the measurement apparatus of Two-dimensional Composites Mode Shape (1), Fourier mode curvature estimation module (2) and judge module (3) it is characterised in that: described Mode Shape measurement apparatus (1) Including for tapping power hammer (4) that the equally distributed measurement point of h is spaced on described Two-dimensional Composites, measuring described measurement point The acceleration transducer (5) of acceleration and Mode Shape measurement module (6), connect the described of described acceleration transducer (5) Mode Shape measurement module (6) is based on described acceleration and generates Mode Shape (w (x, y)), and wherein x, y represent the plane of measurement point Coordinate figure, described Fourier mode curvature estimation module (2) by formula (f1) be calculated Fourier modal curvature (w " (x, Y)),Wherein,

$\frac{{\∂}^2{w}_{x,y}}{\∂x^2}=-\frac{h}{2\mathrm{\π}}\underset{k_x}{\σ}{k}_x^2{e}^{{\mathrm{ik}}_{x}x}{\hat{w}}_{k_x,y},$

$\frac{{\∂}^2{w}_{x,y}}{\∂y^2}=-\frac{h}{2\mathrm{\π}}\underset{k_y}{\σ}{k}_y^2{e}^{{\mathrm{ik}}_{y}y}{\hat{w}}_{x,k_y},$

${\hat{w}}_{k_x,y}=\underset{x}{\σ}{e}^{-{\mathrm{ik}}_{x}x}{w}_{x,y},$

${\hat{w}}_{x,k_y}=\underset{y}{\σ}{e}^{-{\mathrm{ik}}_{y}y}{w}_{x,y}---\left(f1\right),$

Wherein, h represents described measurement dot spacing, and kx, ky are expressed as the inverse of measurement point x, y-coordinate value, and e represents natural constant, w (x, y) represents measured Mode Shape,

Described judge module (3) connects described Fourier mode curvature estimation module (2), if described Fourier modal curvature (w " (x, y)) is more than predetermined threshold, and described judge module (3) judges described Fourier modal curvature (w " (x, y)) more than predetermined The measurement point of threshold value is damage position.

2. Two-dimensional Composites according to claim 1 damage detection system it is characterised in that: preferably, described pre- Determining threshold value is the given threshold value of 3 σ criterions.

3. Two-dimensional Composites according to claim 1 damage detection system it is characterised in that: described two dimension composite wood The damage detection system of material also includes graphics module (7), and described graphics module (7) connects described Mode Shape measurement module (6) And draw Mode Shape curve, described graphics module (7) connects described Fourier mode curvature estimation module (2) and draws Fourier Leaf modal curvature curve.

4. Two-dimensional Composites according to claim 3 damage detection system it is characterised in that: described Mode Shape is bent Line is 1-4 order mode state mode curve.

5. Two-dimensional Composites according to claim 1 damage detection system it is characterised in that: between described measurement point is It is multiplied by 8 every h equally distributed 8 and is multiplied by n measurement point, wherein n is the exponent number of Mode Shape.

6. Two-dimensional Composites according to claim 1 damage detection system it is characterised in that: described Fourier mode Curvature estimation module (2) includes computing unit and Fourier transformation unit, and described Mode Shape measurement module (6) is model analyses Equipment, described judge module (3) is digital signal processor.

7. Two-dimensional Composites according to claim 3 damage detection system it is characterised in that: described judge module (3) it is provided with 3 σ threshold filtering modules, described Fourier mode curvature curve (7) is sent out after processing via 3 σ threshold filtering modular filtration Send graphics module (7).

8. a kind of detection side using the damage detection system of Two-dimensional Composites according to any one of claim 1-7 Method, it comprises the following steps:

In first step (s1), described power hammer (4) taps and is spaced the equally distributed measurement point of h in described elongate composite, plus Velocity sensor (5) measures the acceleration of described measurement point, and described Mode Shape measurement module (6) is based on described acceleration and generates Mode Shape (w (x, y)),

In second step (s2), described Fourier mode curvature estimation module (2) is calculated Fourier modulus by formula (f1) State curvature,Wherein,

$\frac{{\∂}^2{w}_{x,y}}{\∂x^2}=-\frac{k}{2\mathrm{\π}}\underset{k_x}{\σ}{k}_x^2{e}^{{\mathrm{ik}}_{x}x}{\hat{w}}_{k_x,y},$

$\frac{{\∂}^2{w}_{x,y}}{\∂y^2}=-\frac{h}{2\mathrm{\π}}\underset{k_y}{\σ}{k}_y^2{e}^{{\mathrm{ik}}_{y}y}{\hat{w}}_{x,k_y},$

${\hat{w}}_{k_x,y}=\underset{x}{\σ}{e}^{-{\mathrm{ik}}_{x}x}{w}_{x,y},$

${\hat{w}}_{x,k_y}=\underset{y}{\σ}{e}^{-{\mathrm{ik}}_{y}y}{w}_{x,y}---\left(f1\right),$

Wherein, h represents described measurement dot spacing, and kx, ky are expressed as the inverse of measurement point x, y-coordinate value, and e represents natural constant, w (x, y) represents measured Mode Shape；

In third step (s3), described judge module (3) connects described Fourier mode curvature estimation module (2), if described Fourier modal curvature (w " (x, y)) is more than predetermined threshold, described judge module (3) judge described Fourier modal curvature (w " (x, y)) more than predetermined threshold measurement point be damage position.

9. detection method according to claim 8 it is characterised in that: described predetermined threshold be the given threshold of 3 σ criterions Value.

10. detection method according to claim 8 it is characterised in that: graphics module (7) connects the measurement of described Mode Shape Module (6) and draw Mode Shape curve, described graphics module (7) connect described Fourier mode curvature estimation module (2) and Draw Fourier mode curvature curve.