CN104267104B - Method for detecting shock-absorption and noise-reduction performance of car damping material - Google Patents
Method for detecting shock-absorption and noise-reduction performance of car damping material Download PDFInfo
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- CN104267104B CN104267104B CN201410490780.2A CN201410490780A CN104267104B CN 104267104 B CN104267104 B CN 104267104B CN 201410490780 A CN201410490780 A CN 201410490780A CN 104267104 B CN104267104 B CN 104267104B
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Abstract
The invention discloses a method for detecting shock-absorption and noise-reduction performance of a car damping material. The method comprises detection on two aspects, i.e. the detection of a damping material on the aspect of the feeling of passengers for the vibration noise in the process of simulating the real driving process, and the detection of the damping material on the aspect of reducing the vibration of the overall structure of a car body and the bias of resonant frequency. By adopting a novel method for detecting the shock-absorption and noise-reduction performance of the damping material which is reasonably combined with the car body of a specific car, the shock-absorption performance index of the damping material applied to the car can be simply and intuitively expressed, the complicated modeling work can be omitted, the detection work is relatively simplified, the result is intuitive and dependable, and the application prospect is remarkable.
Description
Technical field
The invention belongs to damping material detection field, it is related specifically to a kind of car damping material vibration and noise reducing performance detection
Method.
Background technology
Using damping material, vibration and noise reducing process is carried out to automobile, be quite ripe technology.We are in research vapour
During car vibration and noise, generally adopt nvh index.Nvh is exactly noise (noise), vibration (vibration) and sound vibration roughness
(harshness) abbreviation of English word.Because this three typically occur in automobile vibration field simultaneously and also close not
Can divide, so usually triplicity is studied together.Wherein, sound vibration roughness is otherwise known as uneven pliable, is to shaking
The description of dynamic and noise qualities is human body to the subjective sensation of noise and vibration it is impossible to directly be measured with objective measurement method.
Automobile vibrates in the process of moving mainly to be had with the source of noise: the vibration noise that (1) electromotor causes；(2) with
The vibration noise that air relative flow causes；(3) vibration noise that tire scrape along the ground causes；(4) vehicle body drive system gear
Vibration noise produced by engagement；(5) Uneven road and vibration of causing etc..
Can reach the purpose of vibration and noise reducing using damping material.The application of car damping material, mainly for certain vibration
Noise source is targetedly processed from dissimilar damping material it is therefore intended that reducing vibration and noise amplitude, improves
Automobile driver and crew's comfort level, skew vehicle body ad hoc structure resonant frequency point, the structural abrasion of minimizing etc..
Damping material is also referred to as visco-elastic damping material, and its main component is macromolecular material.When damping material is subject to
After force-extension or compression excitation, viscous-elastic behaviour in itself that had due to material, produced response will be more delayed than encouraging.Will be stagnant
Effect afterwards is quantified as angle of lag, and its size just can show that the damping capacity of this material.Body structure framework toast viscous
Knot damping material, the energy of the body vibrations that can dissipate, thus reach the purpose of vibration damping.This method is not changing vehicle body acoustically radiating
In the case of penetrating feature, but can effectively control the extent of vibration of vehicle body, so that noise reduces.
Improve constantly with social progress and living standard, the requirement more and more higher to comfort level by bus for the people.The opposing party
Face, domestic automobile development of manufacturing is rapid, and it is increasingly competitive, and each automobile manufacturing company is numerous and confused to be increased to raising automotive quality
The research of aspect, and nvh has become as the most important technical specification weighing automotive quality.But due in Automobile Design manufacture
Technical elements domestic automobile manufacturing enterprise basis is weaker, in Automobile Design early stage, is difficult to the car of impact car load nvh quality
All key elements such as body structure, chassis vibration damping and power assembly all consider to put in place, therefore always manufacture produce finished car sample car it
Carry out the rectification of car load nvh by applying the means such as damping material more afterwards.So damping material is more next in the application of automobile industry
More paid attention to by producer.
But car damping materials industry has variety of problems, existing evaluation car damping materials'use vibration and noise reducing
Performance indications meet with a variety of puzzlements in actual applications, less adapt to industry development require.Need badly and seek a kind of new energy
For concrete vehicle damping material vibration and noise reducing performance representation and the detection mode supporting with it to adapt to new demand
Situation, this for car damping material select application and on concrete vehicle body damping material configure occupation mode process modification
All important by playing the role of.
Have car damping material property describing mode and concrete vehicle body damping material collocation method at present in dynamic excitation
In the case of identical, the damped coefficient of damping material is bigger, and structural vibration is weaker, noise is lower.In vehicle vibration damping noise reduction engineering
In, the existing selection mode for car damping material, the performance indications of Primary Reference are the energy resistances of damping material structure
Buddhist nun's coefficient.
In actual test, engineering is typically first pasted on the substrate of certain material damping material baking, then right
Structural test piece integrally enters row energization (power or sound) so as to produce corresponding response, because the damping system of response characteristic and material
Number has close contact, is processed by the data and waveform to response and encouraging and is analyzed it becomes possible to determine this knot
The integral damping coefficient of structure.The energy damping coefficient being namely based on certain material structure being tested out by such method.
The domestic existing damping material collocation method for body structure, a part of fund is enriched, technological reserve is more
Producer targetedly configures damping material setting up on the basis of body in white mode carries out model analyses.But due to domestic in correlation
Start late in field, the reason such as technology is less perfect, is commonly present that modeling is inaccurate, model and actual quite different problem, then
When driving a vehicle with the body mode toasted after stickup damping material, reality plus body in white mode, body mode etc. exists more very much not
With practical situation and estimated inconsistent problem often in the application for damping material.Another part producer is to damping
The application of material still relies heavily on original experience, configures according to original similar vehicle damping material on new model
Experience uses damping material, is then passed through simple test, takes advantage of human feeling to arrive the vibration position larger with noise ratio in examination and strengthens
Damping material configures.
But in actual applications, due to the complexity of body structure and environment, when selecting damped products, usually
Even if occurring selecting material performance index to be that structural energy damped coefficient ratio is larger, but the effect of vibration and noise reduction of reality being not to the utmost such as
The situation of people's will.
Xu Fengchen, Li Honglin, Liu Fu. brief talk the method for testing [j] of automobile damping material damped coefficient. automobile technology with
Material, three kinds of method of testings that 2008, the 08:63-67. document are provided, are all bond material structure measurement damped coefficients, then
Apply on integral body, how a pilot process, result can have certain error.
Content of the invention
The invention aims to overcoming the deficiencies in the prior art, provide a kind of car damping material damping noise reduction performance
Detection method, this method avoids the superior and actually used not good blind spot of independent damping property, its vibration and noise reducing performance number
According to intuitively credible, and using relatively easy, the selection to car damping material and vehicle body damping material collocation method improve and have
Important effect.
To achieve these goals, the present invention is achieved by the following technical solutions:
A kind of car damping material damping noise reduction method for testing performance, including the detection of two aspects:
(1) damping material is to the detection taking out the impression aspect to vibration noise for the personnel on car in the actual driving conditions of simulation
This detection comprises the following steps:
A. actuating vehicle under the specified conditions, using the electromotor of described vehicle as primary oscillation source；
B. at seat bottom, rear, the left and right position of described vehicle, armrest with above steering wheel, the vapour that contacts of foot
In-car wall bottom surface arranges acceleration transducer；Along automobile center line human ear height (i.e. chassis counts 1.1m～1.3m), often arrange
Seat arranges a sound pressure sensor, and the signal of acceleration transducer and sound pressure sensor is turned by external a/d by lead-out wire
Parallel operation Real-time Collection current signal, single-chip microcomputer carries out data storage, until stopping sampling, institute when specified requirementss sections of road finishes
Stating data is amplitude and frequency；
C. do not pasted the survey of damping material, former car damping material, experiment damping material respectively to b step according to a of (1)
Amount contrast experiment, its Central Plains car damping material is the damping material bonding method before certain vehicle is improved, and specifically includes damping material
Paste position is distributed, uses damping material species and paste thickness, and experiment damping material adopts different from former car damping material,
Change the distribution of damping material paste position and paste thickness；
D. the data gathering switchs to frequency domain by Fourier transformation and is analyzed, and Data collecting conversion uses in quick Fu
, there is the fixing cycle in leaf transformation: the signal being gathered is periodic signal, acquired signal is with the cycle as substrate, and real
Signal be by this basic cycle produce endless time-domain signal combination；The data length setting time-domain signal is as n, sequence
For x (n), then its Fourier coefficient x (k) can be expressed as follows:Wherein, 0≤k≤n-1, makes wn
=e-2jπ/n, therefore above formula becomesWhen the multiple that the length of time-domain signal is 2, then above formula is expressed as very
Several with even item and, be expressed as follows:Be can be seen that by this formula
Two multinomials on the right of equal sign are decomposed, and continue as procedure described above, accomplish always to only require secondary list
Till the root 1, -1 of position, a recursive resolve scheme is set up by this process；Using wn=e-2jπ/nSymmetryAnd periodicallyIt can be found that the order of x (k) and x (n) is binary number group index after abbreviation
Bit reversal, that is, after the binary numeral of each array indexing of x (n) is write out, the reversion of its order can be obtained x
The corresponding array indexing value of (k), find from the amplitude-versus-frequency curve of vibration signal Oscillation Amplitude maximum waveform (0.5hz～
50hz scope), the amplitude-versus-frequency curve of noise signal finds its second-order resonance frequency waveform (20hz～5000hz scope),
By the resonant frequency size when it resonates for the body structure test specimen and corresponding bandwidth, to determine the damped coefficient of corresponding test specimen
Method be referred to as half-power bandwidth method in engineering, formula is as follows:In formula, fhWhen representing that frequency raises,
Amplitude compares frequency during the little 3db of peak value；flWhen representing that frequency reduces, amplitude compares frequency during the little 3db of peak value；δ f represents
Half-power bandwidth；fnRepresent n-th waveform resonant frequency；Can get sound and the vibration of approximate vehicle body body material structure
Correlation energy damped coefficient η1；
(2) damping material vibrates to vehicle body overall structure minimizing and the detection of resonance point skew aspect
A. automobile body-in-white and multiple vibrator are combined, vibrator provides constant vibration source；
B. in the middle part of the vehicle body main member of described automobile, acceleration transducer is set with resonance position to be offset, is used for
Test this component resonant frequency, and resonance position to be offset according to concrete vehicle, body accessories how many, configured using damping material
Method is different and different；The data variation of acceleration sensor passes through signal lead-out wire by external a/d transducer Real-time Collection electricity
Stream signal, single-chip microcomputer carries out data storage, until the standard sample time terminates to stop sampling, described data is amplitude and frequency；
Described resonance position, different because vehicle structure is different with material, it is distributed in the resonance point of the specific position of automobile, through ability
The normal experiment in domain can determine that position, and resonance significantly place is possible to automotive material and mechanism be caused damage, to noise
Resonance can be empathized, and human body is damaged.
C. damping material, former car damping material, experiment damping material condition are not pasted according to a of (2) respectively to b step
Under multiple spot frequency sweep resonance laboratory and random white noise resonance laboratory successively, the data of collection switchs to frequency domain by Fourier transformation
It is analyzed, the concrete steps of conversion are identical with formula (1) c again.Frequency range to be analyzed is 0～2000hz, main point
Analysis target is resonance point, and that is, the frequency of the one or several point of amplitude highest, can get the vibration of body in white body material structure
Correlation energy damped coefficient η2；
η1And η2Bigger, illustrate that applied damping material vibration and noise reducing performance on certain component of vehicle body is better, for car
The contribution of body structure Global Macros is stronger.The vibration amplitude feelings in 0.5hz～50hz for the Main Basiss frequency range of passenger's impression
Condition, in this frequency range, amplitude is bigger, and the vibration that passenger experiences is more violent；In the same manner, the noise Main Basiss of passenger's impression
Amplitude situation in 20hz～5000hz for the frequency range, amplitude is bigger, and noise is more ear-piercing, and energy damping coefficient η1And η2More
Greatly, show that vibration that passenger experiences and noise are weaker, the configuration mode in this position for this damping material is closer to optimum；
The present invention is tested with former car damping material and experiment damping material, illustrates present invention may apply to multiple types
The damping material of type.
The condition specified described in (1) a above, be electromotor be in idling, acceleration and basic, normal, high at the uniform velocity in the case of.
The above idling is 700r/min, and described acceleration is 700r/min-2500r/min, described low is at the uniform velocity
1400r/min, described at the uniform velocity be 2000r/min, described height at the uniform velocity be 2500r/min.
The above vehicle body main member includes: hood, front mudguard, cowl upper, front panel, covering for roofs,
Front pillar, roof side rail, top cover side plate, rear deck panel, rear pillar, squab panel, rear fender, center pillar, car door, lower-edge beam, base plate, front
Beater or beat-up, front longitudinal, front beam, front valance panel, radiator frame, hood front end panel.
The experiment condition of the above multiple spot frequency sweep resonance laboratory successively is: its experiment condition is: experiment place: half noise reduction
Room；Experimental subject: body in white；Experiment condition: vehicle body hangs, and is placed in the geometrically symmetric point of body-in-white structure using vibrator, specifically
Position is that the former tire location of vehicle body places 4 vibrators, and setting vibrator frequency is that frequency sweep excites successively.
The experiment condition of the above random white noise resonance laboratory is: its experiment condition is: experiment place: half noise reduction
Room；Experimental subject: body in white；Experiment condition: hang, the geometrically symmetric point of body-in-white structure, particular location are placed in using vibrator
Place 4 vibrators for the former tire location of vehicle body, setting vibrator frequency excites for same frequency white noise.
Experiment damping material used by the present invention, is application number: the automobile-used siloxanes damped elasticity of 201310077414.x
Body formula is it may be assumed that polysiloxanes matrix resin 100 weight portion；The oligomeric polyester polyhydric alcohol 10-20 weight of number-average molecular weight 100-150
Amount part, organobentonite 1-5 weight portion, silicone oil 50-60 weight portion, silicon dioxide powder 20-30 weight portion, glass microballoon 20-30
Weight portion, antioxidant 2-3 weight portion, oligomeric polyester polyhydric alcohol and bentonite weight are than for 4-6: 1.Silicon dioxide powder
Account for the 15-20% of composition total weight number with the parts by weight sum of glass microballoon.The granularity of silicon dioxide powder is that 50-80 is micro-
Rice.Glass microballoon is hollow granularity 50-100 micron.Glass microballoon is hollow granularity 50-100 micron.
Compared with prior art, the invention has the beneficial effects as follows: damping material integrally measures directly in conjunction with concrete car body, goes
Except damping property measurement lose contact with reality car body the drawbacks of, obtained damping property more can reflect actually used feelings
Condition.
The present invention is directed to concrete vehicle, and the new method organically combining detection damping material vibration and noise reducing performance with vehicle body can letter
Damping property index in single visual representations car damping materials application, bypassing Complex Modeling work makes detection work relatively easy
Change, its visual result is credible simultaneously, has suitable application prospect.
Brief description
Fig. 1 is vehicle body main member structural representation of the present invention；
Fig. 2 is body in white of the present invention and vibrator combining structure schematic diagram.
Reference: 1- hood, 2- front mudguard, 3- cowl upper, 4- front panel, 5- covering for roofs, 6- front pillar,
7- roof side rail, 8- top cover side plate, 9- rear deck panel, 10- rear pillar, 11- squab panel, 12- rear fender, 13- center pillar, 14- car
Door, 15- lower-edge beam, 16- base plate, 17- wing, 18- front longitudinal, 19- front beam, 20- front valance panel, 21- radiator frame,
22- hood front end panel, 23- body in white, 24- acceleration sensor, 25- vibrator.
Specific embodiment
With reference to embodiment, the present invention is described in further detail, but embodiments of the present invention are not limited to
The scope that embodiment represents.
Embodiment 1:
From certain brand automobile, damp composite material 1 carries out vibration and noise reducing performance detection, and damp composite material 1 is application
Number: embodiment 1 product of 201310077414.x, in the reactor of 2.5l, add 600 grams of polysiloxanes matrix resins, such as
Polydimethylsiloxane etc., by 6 grams of organobentonite, 60 grams of the oligomeric polyester polyhydric alcohol of number-average molecular weight 100,300 grams of silicone oil,
With 12 grams of antioxidant after 120 grams of particle diameter 50 hum silicon dioxide silica flour and particle diameter 120 grams of mix homogeneously of 50 urn glass microballon
Add together in reactor, stirring, mixing speed is 120raund/min, temperature programming simultaneously, programming rate is 5 DEG C/min,
It is incubated 1h after being warming up to 90 DEG C, mediate 30-90min extruding pelletization at 120 DEG C.Gained elastomer is at 25 DEG C and 60 DEG C
Vibration damping be 17 and 22,25 DEG C after sample aging 3 months at vibration damping reduce 4.
(1) damping material is to the detection taking out the impression aspect to vibration noise for the personnel on car in the actual driving conditions of simulation
This detection comprises the following steps:
A. actuating vehicle under the specified conditions, using the electromotor of vehicle as primary oscillation source；The condition specified, for sending out
Motivation be in idling (700r/min), accelerate (700r/min- > 2500r/min) and low (1400r/min), in (2000r/
Min), high (2500r/min) at the uniform velocity in the case of.
B. at seat bottom, rear, the left and right position of vehicle, armrest with above steering wheel, in the automobile that contacts of foot
Wall bottom surface arranges acceleration transducer；Along automobile center line human ear height (i.e. 1.2m), often one acoustic pressure sensing of row's seat setting
The signal of device, acceleration transducer and sound pressure sensor passes through lead-out wire by external a/d transducer Real-time Collection current signal,
Single-chip microcomputer carries out data storage, until stopping sampling when specified requirementss sections of road finishes, data is amplitude and frequency；Specified bar
The section of part is straight cement flooring, and long 1000 meters, ground is gentle.
C. damping material, former car damping material (damping material thickness are not pasted according to a of (1) respectively to b step
3.5mm, paste position: immediately below automobile engine operator seat, bonding area: 14*45mm, sampled point is just to paste damping material
Middle), experiment damping material (damping material thickness 5mm, paste position: immediately below automobile engine operator seat, bonding area:
14*45mm, sampled point be paste damping material middle) measurement contrast experiment
The data collecting is as shown in table 1:
Table 1
The data of collection switchs to frequency domain by Fourier transformation and is analyzed, and Data collecting conversion uses fast Fourier
Conversion: the signal being gathered is periodic signal, there is the fixing cycle, acquired signal is with the cycle as substrate, and real
Signal is the combination of the time-domain signal being produced endless by this basic cycle；Set the data length of time-domain signal as n, sequence is
X (n), then its Fourier coefficient x (k) can be expressed as follows:Wherein, 0≤k≤n-1, makes wn=
e-2jπ/n, therefore above formula becomesWhen the multiple that the length of time-domain signal is 2, then above formula is represented by
Odd term and even item and, be expressed as follows:Can be seen by this formula
Go out, two multinomials on the right of equal sign will be decomposed, and continue as procedure described above, accomplish to only require secondary always
Unit root 1, till -1, sets up a recursive resolve scheme by this process；Using wn=e-2jπ/nSymmetryAnd periodicallyIt can be found that the order of x (k) and x (n) is binary number group index after abbreviation
Bit reversal, that is, after the binary numeral of each array indexing of x (n) is write out, the reversion of its order can be obtained x
The corresponding array indexing value of (k)；Find from the amplitude-versus-frequency curve of vibration signal Oscillation Amplitude maximum waveform, 0.5hz～
In the range of 50hz；Find its second-order resonance frequency waveform in the amplitude-versus-frequency curve of noise signal, in 20hz～5000hz model
In enclosing, by the resonant frequency size when it resonates for the body structure test specimen and corresponding bandwidth, to determine the resistance of corresponding test specimen
The method of Buddhist nun's coefficient is referred to as half-power bandwidth method in engineering, can get the energy damping coefficient η 1 of body material structure,In formula, fhWhen representing that frequency raises, amplitude compares frequency during the little 3db of peak value；flRepresent that frequency reduces
When, amplitude compares frequency during the little 3db of peak value；δ f represents half-power bandwidth；fnRepresent n-th waveform resonant frequency；By
This vibration of body material structure that can get the actual vehicle body of each condition lower aprons and sound correlation energy damped coefficient η1.Result
As shown in table 2:
Table 2
| Calculate data | Do not paste damping material | Former car damping material experiment | Experiment damping material |
| fhSound | \ | 23.0hz | 19.3hz |
| flSound | \ | 35.6hz | 34.7hz |
| fnSound | 28.08hz | 27.9hz | 28.08hz |
| fhShake | \ | 135.7hz | 124.9hz |
| flShake | \ | 212.3hz | 217.4hz |
| fnShake | 169.3hz | 169.1hz | 169.1hz |
| η1 | Can not survey, minimum | 0.45 | 0.55 |
By table 2 it is recognised that this brand automobile, driving a vehicle under condition of similarity with actual, in automobile engine operator seat seat
Thicken damping material stickup thickness immediately below chair and can reduce vibration and noise to a certain extent, this is that original damping material is joined
Put a kind of of method and optimize direction.
(2) damping material is to the detection taking out the impression aspect to vibration noise for the personnel on car in the actual driving conditions of simulation
This detection comprises the following steps:
A. automobile body-in-white and multiple vibrator are combined, vibrator provides constant vibration source；
B. (whole critical pieces have) and resonance position (resonance part to be offset in the middle part of the vehicle body main member of automobile
Position is tried to achieve by test) setting acceleration transducer, for testing this component resonant frequency, and resonance position to be offset is according to tool
Body vehicle, body accessories are how many, different using damping material collocation method difference；The data variation of acceleration sensor passes through letter
, by external a/d transducer Real-time Collection current signal, single-chip microcomputer carries out data storage for number lead-out wire, until the standard sample time
(60s) terminate to stop sampling, described data is amplitude and frequency；
C. according to (2) a to b step do not pasted respectively damping material, former car damping material (damping material thickness 5mm,
Paste position: immediately below car steering position, bonding area: 14*45mm, sampled point be paste damping material middle), experiment resistance
Under the conditions of damping material (damping material thickness 5mm, paste position: immediately below car steering position, original position 5cm to the left, sticking veneer
Long-pending: 14*45mm, sampled point is to paste damping material middle) multiple spot successively frequency sweep resonance laboratory (swept-frequency signal is standard sine
Signal, vibrator electric current 2.0a, test under the conditions of voltage 4.1v) and random white noise resonance laboratory, the data of collection is by Fu
In leaf transformation switch to frequency domain and be analyzed again, the concrete steps of conversion are identical with formula (1) d.Frequency range to be analyzed is 0
～2000hz, Main Analysis target is resonance point, i.e. the frequency of the one or several point of amplitude highest.
The data collecting is as shown in table 3:
Table 3
The data of collection switchs to frequency domain by Fourier transformation and is analyzed, and Data collecting conversion uses fast Fourier
Conversion: the signal being gathered is periodic signal, there is the fixing cycle, acquired signal is with the cycle as substrate, and real
Signal is the combination of the time-domain signal being produced endless by this basic cycle；Set the data length of time-domain signal as n, sequence is
X (n), then its Fourier coefficient x (k) can be expressed as follows:Wherein, 0≤k≤n-1, makes wn=
e-2jπ/n, therefore above formula becomesWhen the multiple that the length of time-domain signal is 2, then above formula is expressed as odd number
With even item and, be expressed as follows:Be can be seen that by this formula will
Two multinomials on the right of equal sign are decomposed, and continues as procedure described above, accomplish always to only require secondary unit
Root 1, till -1, sets up a recursive resolve scheme by this process；Using wn=e-2jπ/nSymmetry
And periodicallyIt can be found that the order of x (k) and x (n) is the bit reversal of binary number group index, also after abbreviation
Be the binary numeral of each array indexing of x (n) is write out after, the reversion of its order can be obtained the corresponding array of x (k)
Index value；From the amplitude-versus-frequency curve of vibration signalLook forTo Oscillation Amplitude maximum waveform, in the range of 0.5hz～50hz；?
Its second-order resonance frequency waveform is found, in the range of 20hz～5000hz, by vehicle body in the amplitude-versus-frequency curve of noise signal
The resonant frequency size when it resonates for the structural test piece and corresponding bandwidth, to determine that the method for the damped coefficient of corresponding test specimen exists
It is referred to as half-power bandwidth method in engineering,In formula, fhWhen representing that frequency raises, amplitude compares the little 3db of peak value
When frequency；flWhen representing that frequency reduces, amplitude compares frequency during the little 3db of peak value；δ f represents half-power bandwidth；fnRepresent the
N waveform resonant frequency；The vibration correlation energy damping system of body in white body material structure under the conditions of thus can get respectively
Number η2.Result is as shown in table 4:
Table 4
| Calculate data | Do not paste damping material | Former car damping material experiment | Experiment damping material |
| fh | \ | 134.2hz | 116.5hz |
| fl | \ | 227.3hz | 214.6hz |
| fn | 169.1hz | 169.0hz | 169.4hz |
| η2 | Can not survey | 0.55 | 0.58 |
By table 4 interpretation, under body-in-white structure test case, immediately below vehicle body operator seat, damp material
Material paste position left shift certain position is had based on the vibrational energy damped coefficient of vehicle body with noise, raising for reducing vibration
Part helps.
Test: the inventive method and original method record the contrast of damping material damped coefficient
Subjects: damp composite material 1, damp composite material 2
Damp composite material 1 is application number mentioned above: embodiment 1 product of 201310077414.x；
Damp composite material 2 is embodiment 2 product of application number: 201310077414.x, that is, in the reactor of 2.5l
Add 600 grams of polysiloxanes matrix resins, such as polydimethylsiloxane etc., by 20 grams of organobentonite, number-average molecular weight 100
80 grams of oligomeric polyester polyhydric alcohol, 330 grams of silicone oil, 150 grams of particle diameter 70 hum silicon dioxide silica flour and particle diameter 75 urn glass microballon
Add together with 15 grams of antioxidant in reactor after 150 grams of mix homogeneously, stirring, mixing speed is 120raund/min, with
When temperature programming, programming rate be 5 DEG C/min, after being warming up to 90 DEG C be incubated 1h, at 120 DEG C mediate 30-90min extrusion make
Grain.Vibration damping at 25 DEG C and 60 DEG C for the gained elastomer be 18 and 24,25 DEG C after sample aging 3 months at vibration damping subtract
Little by 5.
Original method: Xu Fengchen, Li Honglin, Liu Fu. brief talk the method for testing [j] of automobile damping material damped coefficient.
Automobile Technology and Material, 2008,08:63-67. according to the document cantilever method, bond material structure measurement damped coefficient.
Experimental condition of the present invention: test site: semi-anechoic room, standard body in white, test is carried out at twice, respectively two kinds
Damping material same thickness (0.45mm), is pasted onto vehicle body same location (immediately below this brand automobile second row left side seat),
Same (the 80cm of bonding area2), excitation is similarly standard sine wave vibrational excitation, frequency 80hz, and sampled point is to paste damping material
Material middle.
Obtained by computing, result is as shown in table 5:
Table 5
| Composite damping material 1 | Composite damping material 2 | |
| Original method records damped coefficient | 0.3 | 0.5 |
| New method records damped coefficient | η2=0.35 | η2=0.45 |
By table 5 experimental design it is clear that the damping material vibration and noise reducing performance obtained by the inventive method is more directly perceived
Credible.From result of the test it is recognised that serviceability immediately below the seat of the vehicle body second row left side for the composite damping material 1 is low
Estimate (new method test result and original method test result compare), and composite 2 is overestimated in its serviceability of this position.
Measurement result of the present invention is more intuitively credible, is the angle based on application.The damped coefficient of former method measurement is based on tool
Body material structure, is to record on concrete material (such as with vehicle body a part material identical steel plate model), and newly proposes
Measuring method be then directly to test on vehicle body, so the conclusion drawing to compare former method naturally more intuitively credible.
There is certain deviation in actual applications in the damped coefficient measured by former method, because recording resistance in small pieces of material
Buddhist nun's coefficient, reapplies on integral body, how a pilot process, certainly exists error, new method is from practical application angle
Omit pilot process, obtain is inevitable in actual use more intuitively credible based on vehicle body concrete position damped coefficient.
In practical application angle, the inventive method is advantageously.
Claims (6)
1. a kind of car damping material vibration and noise reducing method for testing performance is it is characterised in that include the detection of two aspects:
(1) damping material to simulate the detection that the impression aspect to vibration noise for the personnel is taken out in actual driving conditions on car this
Detection comprises the following steps:
A. actuating vehicle under the specified conditions, using the electromotor of described vehicle as primary oscillation source；
B. at seat bottom, rear, the left and right position of described vehicle, armrest with above steering wheel, in the automobile that contacts of foot
Wall bottom surface arranges acceleration transducer；Along automobile center line human ear height, often one sound pressure sensor of row's seat setting, acceleration
The signal of sensor and sound pressure sensor passes through lead-out wire by external a/d transducer Real-time Collection current signal, and single-chip microcomputer enters
Row data storage, until stopping sampling when specified requirementss sections of road finishes, described data is amplitude and frequency；
C. according to (1) a to b step do not pasted respectively damping material, former car damping material, experiment damping material measurement right
Ratio experiment, its Central Plains car damping material is the damping material bonding method before certain vehicle is improved, including damping material paste position
It is distributed, uses damping material species and paste thickness, experiment damping material adopts different from former car damping material, and change damps
The distribution of material paste position and stickup thickness；
The data of collection switchs to frequency domain by Fourier transformation and is analyzed, and Data collecting conversion is become using fast Fourier
Change: the signal being gathered is periodic signal, there is the fixing cycle, acquired signal is with the cycle as substrate, and real letter
Number it is the combination of the time-domain signal being produced endless by this basic cycle；Set the data length of time-domain signal as n, sequence is x
(n), then its Fourier coefficient x (k) can be expressed as follows:Wherein, 0≤k≤n-1, makes wn=e-2jπ/n, therefore above formula becomesWhen the multiple that the length of time-domain signal is 2, then above formula is expressed as odd number
With even item and, be expressed as follows:Be can be seen that by this formula will
Two multinomials on the right of equal sign are decomposed, and continues as procedure described above, accomplish always to only require secondary unit
Root 1, till -1, sets up a recursive resolve scheme by this process；Using wn=e-2jπ/nSymmetry
And periodicallyIt can be found that the order of x (k) and x (n) is the bit reversal of binary number group index, also after abbreviation
Be the binary numeral of each array indexing of x (n) is write out after, the reversion of its order can be obtained the corresponding array of x (k)
Index value；Oscillation Amplitude maximum waveform is found from the amplitude-versus-frequency curve of vibration signal, in the range of 0.5hz～50hz；?
Its second-order resonance frequency waveform is found, in the range of 20hz～5000hz, by vehicle body in the amplitude-versus-frequency curve of noise signal
The resonant frequency size when it resonates for the structural test piece and corresponding bandwidth, to determine that the method for the damped coefficient of corresponding test specimen exists
Half-power bandwidth method is referred to as on engineering, formula is as follows:In formula, fhWhen representing that frequency raises, amplitude is compared
Frequency during the little 3db of peak value；flWhen representing that frequency reduces, amplitude compares frequency during the little 3db of peak value；δ f represents half power bandwidth
Wide；fnRepresent n-th waveform resonant frequency；Can get the approximately sound of actual vehicle body body material structure related with vibration
Energy damping coefficient η1；
(2) damping material vibrates to vehicle body overall structure reduction and the detection of resonant frequency shift aspect:
A. automobile body-in-white and multiple vibrator are combined, vibrator provides constant vibration source；
B. place acceleration transducer in the vehicle body main member horizontal middle of described automobile and resonance position to be offset, be used for
Test this component resonant frequency, the data variation of acceleration sensor is adopted by external a/d transducer in real time by signal lead-out wire
Colleeting comb signal, single-chip microcomputer carries out data storage, until stopping after the standard for manual sampling period, described data is amplitude and frequency；
C. under the conditions of not pasted damping material, former car damping material respectively, tested damping material to b step according to a of (2)
Multiple spot frequency sweep resonance laboratory and random white noise resonance laboratory successively, its Central Plains car damping material is the damping before certain vehicle is improved
Material bonding method, including the distribution of damping material paste position, using damping material species and stickup thickness, tests damping material
Adopt different from former car damping material, change the distribution of damping material paste position and paste thickness；The data of collection passes through Fu
In leaf transformation switch to frequency domain and be analyzed again, the concrete steps of conversion are identical with step (1) c；Frequency range to be analyzed be 0～
2000hz, Main Analysis target is resonance point, and that is, the frequency of the one or several point of amplitude highest, can get body in white vehicle body material
The vibration correlation energy damped coefficient η of material structure2；
η1And η2Bigger, illustrate that applied damping material vibration and noise reducing performance on certain component of vehicle body is better, for vehicle body knot
The contribution of structure Global Macros is stronger.
2. a kind of car damping material vibration and noise reducing method for testing performance according to claim 1 it is characterised in that: (1) a
In the condition specified, be electromotor be in idling, acceleration and basic, normal, high at the uniform velocity in the case of.
3. a kind of car damping material vibration and noise reducing method for testing performance according to claim 2 it is characterised in that: described
Idling be 700r/min, described acceleration be 700r/min-2500r/min, described low at the uniform velocity be 1400r/min, described at the uniform velocity
For 2000r/min, described height is at the uniform velocity 2500r/min.
4. a kind of car damping material vibration and noise reducing method for testing performance according to claim 1 it is characterised in that: described
Vehicle body main member includes: hood, front mudguard, cowl upper, front panel, covering for roofs, front pillar, roof side rail, top cover
Side plate, rear deck panel, rear pillar, squab panel, rear fender, center pillar, car door, lower-edge beam, base plate, wing, front longitudinal, front
Crossbeam, front valance panel, radiator frame and hood front end panel.
5. a kind of car damping material vibration and noise reducing method for testing performance according to claim 1 it is characterised in that: described
Multiple spot frequency sweep resonance laboratory successively, its experiment condition is: experiment place: semi-anechoic room；Experimental subject: body in white；Experiment condition:
Vehicle body hangs, and is placed in the geometrically symmetric point of body-in-white structure using vibrator, and particular location is that vehicle body former tire location placement 4 swashs
Shake device, and setting vibrator frequency is that frequency sweep excites successively, and 4 vibrator simultaneous shot signals are tested.
6. a kind of car damping material vibration and noise reducing method for testing performance according to claim 1 it is characterised in that: described
Random white noise resonance laboratory, its experiment condition is: experiment place: semi-anechoic room；Experimental subject: body in white；Experiment condition: outstanding
Hang, the geometrically symmetric point of body-in-white structure be placed in using vibrator, particular location is that the former tire location of vehicle body places 4 vibrators,
Setting vibrator frequency excites for same frequency white noise, and 4 vibrator simultaneous shot signals are tested.
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| CN104596718A (en) * | 2015-02-28 | 2015-05-06 | 重庆长安汽车股份有限公司 | Demonstration method for acoustic radiation phenomenon of vehicle stamping part |
| CN104792877B (en) * | 2015-04-03 | 2017-05-17 | 浙江大学 | Method for measuring decoupling performance of underwater decoupling and vibration reducing material |
| US10328944B2 (en) * | 2017-04-04 | 2019-06-25 | Ford Global Technologies, Llc | Systems and methods for active engine mount diagnostics |
| CN107607333B (en) * | 2017-09-22 | 2019-11-08 | 太原科技大学 | A kind of vehicle damping material vibration damping test method |
| CN109827728B (en) * | 2019-03-06 | 2020-10-09 | 北京市劳动保护科学研究所 | Damping structure noise reduction performance test support, test device and method |
| WO2021077449A1 (en) * | 2019-10-24 | 2021-04-29 | 东北大学 | Integrated tester for shock absorption, noise reduction and impact resistance of composite materials and test method |
| CN113408043B (en) * | 2020-03-17 | 2024-04-05 | 宇通客车股份有限公司 | Whole vehicle tire matching method and device |
| CN112697369A (en) * | 2020-12-29 | 2021-04-23 | 贵州联洪合成材料有限公司 | Method for testing and evaluating vibration attenuation effect of damping fin on body-in-white |
| CN112687150B (en) * | 2021-01-27 | 2022-10-21 | 中国人民警察大学 | Fire-fighting forcible entry training module for car |
| CN112668208B (en) * | 2021-01-29 | 2024-02-23 | 中国汽车工程研究院股份有限公司 | White car body damping pad arrangement simulation method and simulation device |
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