阅读说明：本技术 一种多单元耦合式微穿孔板低频宽带吸声结构及其设计方法 (A kind of multiple-unit manifold type microperforated panel broad band low frequency sound absorption structure and its design method ) 是由 吴九汇 刘崇锐 于 2019-08-20 设计创作，主要内容包括：本发明一种多单元耦合式微穿孔板低频宽带吸声结构及其设计方法,所述结构包括并列连续设置的多个吸声单元,吸声单元包括微穿孔板和背腔；背腔的前端开口,设置微穿孔板,后端封闭设置形成空腔；所有吸声单元的微穿孔板共面设置,所有吸声单元的一阶峰值和至少一个吸声单元的至少一个高阶峰值均匀连续分布,在中低频范围内形成一个连续的多峰值吸声宽带。通过设置多个不同的吸声单元,在组成多个峰值带宽的同时,加入了其中部分吸声单元的高阶峰值进行连续吸声,获得不同频率的吸声峰值；并且通过空间折叠,在不增加结构厚度的前提下,对每个单元可以提供的多个峰值进行利用,峰值带宽更宽,在有限的尺寸范围内,实现对带宽的拓展和组合。(A kind of multiple-unit manifold type microperforated panel broad band low frequency sound absorption structure of the present invention and its design method, the structure include the multiple sound absorption units being continuously arranged side by side, and sound absorption unit includes microperforated panel and back chamber；The front opening of chamber is carried on the back, microperforated panel is set, back-end closure is arranged to form cavity；The microperforated panel of all sound absorption units is coplanar with, at least one high-order peak value uniformly continuous distribution of the single order peak value and at least one sound absorption unit of all units that absorb sound forms a continuous multi-peak sound absorption broadband in middle low-frequency range.By the way that multiple and different sound absorption units is arranged, while forming multiple peak bandwidths, the high-order peak value that joined part of sound absorption unit is continuously absorbed sound, and obtains the sound absorption peak value of different frequency；And multiple peak values that each unit can provide are utilized under the premise of not increasing structural thickness by space folding, peak bandwidth is wider, in limited size range, realizes the expansion and combination to bandwidth.)

1. a kind of multiple-unit manifold type microperforated panel broad band low frequency sound absorption structure, which is characterized in that including what is be continuously arranged side by side Multiple sound absorption units, the sound absorption unit include microperforated panel (10) and back chamber (11)；

The front opening of the back chamber (11) is arranged microperforated panel (10), and back-end closure is arranged to form cavity；

The microperforated panel (10) of all sound absorption units is coplanar with, and the single order peak value of all sound absorption units and at least one sound absorption are single At least one high-order peak value uniformly continuous distribution of member forms a continuous multi-peak sound absorption broadband in middle low-frequency range.

2. a kind of multiple-unit manifold type microperforated panel broad band low frequency sound absorption structure according to claim 1, which is characterized in that The biggish sound absorption unit back chamber of thickness carries out space folding in adjacent sound absorption unit, and rear end bending extends to the lesser suction of thickness Below sound unit.

3. a kind of multiple-unit manifold type microperforated panel broad band low frequency sound absorption structure according to claim 1, which is characterized in that Perforation on the microperforated panel (10) is uniformly distributed.

4. a kind of multiple-unit manifold type microperforated panel broad band low frequency sound absorption structure according to claim 1 or 3, feature exist In the shape of, the microperforated panel (10) perforation be round, rectangular, triangle or ellipse, penetration hole diameter for 0.5mm~ 1mm, the punching rate of perforation are 1%~15%, microperforated panel 10 with a thickness of 0.5mm~2mm；When perforation is non-circular, directly Diameter refers to the circumscribed circle diameter of perforation.

5. a kind of multiple-unit manifold type microperforated panel broad band low frequency sound absorption structure according to claim 1, which is characterized in that 4-12 sound absorption unit being continuously arranged side by side.

6. a kind of multiple-unit manifold type microperforated panel broad band low frequency sound absorption structure according to claim 1, which is characterized in that The section for carrying on the back chamber (11) is shape changeable, circle or irregular closed curve, and back chamber (11) sectional area for the unit that absorbs sound is 100mm² ~1 × 10⁴mm²。

7. a kind of multiple-unit manifold type microperforated panel broad band low frequency sound absorption structure according to claim 1, which is characterized in that It further include the structural framing (9) intersected to form by unit interval plate (12), for opening each sound absorption cell isolation；Structural framing (9) it is provided with closed shell, one end that shell corresponds to microperforated panel (10) is provided with one-to-one with microperforated panel (10) Opening.

8. a kind of multiple-unit manifold type microperforated panel broad band low frequency sound absorption structure according to claim 1, which is characterized in that Structural framing (9) and microperforated panel (11) use metal, rigid plastics and resin, are processed by 3D printing or mold.

9. a kind of design of the multiple-unit manifold type microperforated panel broad band low frequency sound absorption structure as described in claim 1-8 any one Method, which is characterized in that

Step 1, model is arranged；

It is each sound absorption unit of sound absorption structure is equivalent at mass-spring system, wherein equivalent mass derives from microperforated panel (10) the air quality in perforation, equivalent damping derive from the damping of perforated wall, and equivalent spring rigidity is the intracavitary portion of back Air rigidity；By adjusting the structural parameters of different sound absorption units, the sound absorption peak value of different frequency is obtained；The structure ginseng Number includes the parameter of microperforated panel (10) and the parameter of back chamber (11)；The parameter of microperforated panel (10) includes the diameter of perforation, depth Punching rate on degree and microperforated panel (10)；The parameter for carrying on the back chamber (11) includes the back chamber determined by two parameters of sectional area and depth Volume；

Step 2, absorption peak quantity determines；

According to all sound absorption peaks of the m unit that absorbs sound in target frequency bands (f_A~f_B) domestic demand continuous uniform distribution requirement, obtain peak It is worth quantity n=(f_A-f_B)/Δ B, wherein Δ B is peak bandwidth；

Step 3, absorptive unit structural parameters determine；

First, the structural parameters of a sound absorption unit are determined, so that its single order crest frequency is f_AAnd it is corresponding high in target frequency bands Then rank crest frequency designs other units, according to the quantity s of high-order peak values all in target frequency bands, obtain sound absorption unit Quantity m=n-s；

Second, in the identical situation of holding unit sectional area, the back chamber depth for successively obtaining sound absorption unit i is as follows,

Wherein, the value range of i is 1 to m, and s ' is the high-order number of peaks that existing unit provides, and range arrives s, l for 0₁It is first The back chamber thickness of sound absorption unit, l_iFor the back chamber thickness of the i-th sound absorption unit；High-order peak value is successively mentioned by determining sound absorption unit For；

Step 4, the space folding arrangement of absorptive unit；

The absorptive unit continuous and parallel determined is arranged, it, will be in adjacent sound absorption unit in the design thickness of sound absorption structure The biggish sound absorption unit back chamber of thickness carries out space folding, and rear end bending extends to below the lesser sound absorption unit of thickness.

10. the design method of multiple-unit manifold type microperforated panel broad band low frequency sound absorption structure according to claim 9, feature It is,

The single order crest frequency of sound absorption unit is related with the hole dimension of microperforated panel (10) and back chamber (11) size, penetration hole diameter Smaller, equivalent mass is bigger, and crest frequency is lower；Penetration depth is bigger, i.e. the thickness of microperforated panel is bigger, and crest frequency is got over It is low；The punching rate of perforation is smaller, and crest frequency is lower；Cavity volume is bigger, and equivalent stiffness is smaller, and sound absorption peak value is moved to low frequency It is dynamic；

The peak bandwidth of sound absorption unit is mainly related with hole dimension and the sound absorption quantity m of unit, and penetration hole diameter is smaller, damping effect Fruit is more obvious, and peak bandwidth is wider；Penetration depth is bigger, and peak bandwidth is wider；Absorb sound element number it is more, peak bandwidth by It is decrescence small.

Technical field

The present invention relates to low frequency vibration damping noise reduction field, specially a kind of multiple-unit manifold type microperforated panel broad band low frequency sound absorption Structure and its design method.

Background technique

Noise pollution has become one of four big pollutions of the world today at present, and very big harm is caused to human health, People's daily life quality is seriously affected, wherein maximum with the harm that low-frequency noise (200Hz~1500Hz) is generated.And it passes The sound-absorbing material (such as microperforated panel and porous material) of system is lower to the dissipation efficiency of low-frequency sound wave, and Yao Shixian fully absorbs low Frequency sound wave, structural thickness size is very huge (20cm or more), can not carry out engineer application.Therefore, a kind of small size is designed The sound absorption structure of (10cm or less) effectively absorbs low-frequency sound wave and is of great significance.

In recent years, the fast development of acoustic metamaterial is solves the problems, such as that low-frequency noise provides new approach, wherein space Folded form Meta Materials cause the concern of researcher by excellent low frequency characteristic.Space folding type Meta Materials are a kind of resonance Type Meta Materials add the modes such as partition, the folding so that propagation path bends, to reduce propagation by carrying on the back intracavitary portion at it The sectional area in path increases its path length, drops low back chamber equivalent spring rigidity, may finally carry on the back chamber volume guaranteeing structure In the case where product, so that sound absorption peak value is significantly mobile to low frequency.But due to the limitation of resonance characteristics, peak bandwidth compared with It is narrow, it is unable to satisfy the demand of broadband sound absorption.Realize that the broadband most effective method of sound absorption is exactly to introduce multiple sound absorption units at present, after And obtain the continuous sound absorption broadband being made of multiple peak values.But element number is limited by structure average impedance, Zhi Neng Value in a certain range, number of peaks and wide band sound absorption can be also limited, still can not very good solution limit size range in Broad band low frequency absorb sound problem.

Summary of the invention

Aiming at the problems existing in the prior art, the present invention provides a kind of multiple-unit manifold type microperforated panel broad band low frequency suction Acoustic form and its design method, which has a compact structure and a reasonable design, wide band sound absorption is big, and broadband is continuous, meets sound absorption demand.

The present invention is to be achieved through the following technical solutions:

A kind of multiple-unit manifold type microperforated panel broad band low frequency sound absorption structure, including the multiple sound absorption lists being continuously arranged side by side Member, the sound absorption unit include microperforated panel and back chamber；

The front opening of the back chamber, is arranged microperforated panel, back-end closure is arranged to form cavity；

The microperforated panel of all sound absorption units is coplanar with, and the single order peak value of all sound absorption units and at least one sound absorption are single At least one high-order peak value uniformly continuous distribution of member forms a continuous multi-peak sound absorption broadband in middle low-frequency range.

Preferably, the biggish sound absorption unit back chamber of thickness carries out space folding in adjacent sound absorption unit, and rear end bending is prolonged It extends to below the lesser sound absorption unit of thickness.

Preferably, the perforation on the microperforated panel is uniformly distributed.

Further, the shape of microperforated panel perforation is round, rectangular, triangle or ellipse, and penetration hole diameter is 0.5mm~1mm, the punching rate of perforation are 1%~15%, microperforated panel 10 with a thickness of 0.5mm~2mm；When perforation is non-circular When shape, diameter refers to the circumscribed circle diameter of perforation.

Preferably, 4-12 sound absorption unit being continuously arranged side by side.

Preferably, the section for carrying on the back chamber is shape changeable, circle or irregular closed curve, and the back chamber sectional area for the unit that absorbs sound is 100mm²~1 × 10⁴mm²。

It preferably, further include the structural framing intersected to form by unit interval plate, for opening each sound absorption cell isolation； Structural framing is provided with closed shell, and one end that shell corresponds to microperforated panel is provided with opens correspondingly with microperforated panel Mouthful.

Preferably, structural framing and microperforated panel use metal, rigid plastics and resin, are processed by 3D printing or mold It is made.

A kind of design method of multiple-unit manifold type microperforated panel broad band low frequency sound absorption structure described in any one as above, packet It includes,

Step 1, model is arranged；

It is each sound absorption unit of sound absorption structure is equivalent at mass-spring system, wherein equivalent mass derives from micropunch Air quality in the perforation of plate, equivalent damping derive from the damping of perforated wall, and equivalent spring rigidity is the intracavitary portion of back Air rigidity；By adjusting the structural parameters of different sound absorption units, the sound absorption peak value of different frequency is obtained；The structural parameters The parameter of parameter and back chamber including microperforated panel；The parameter of microperforated panel includes on diameter, depth and the microperforated panel of perforation Punching rate；The parameter for carrying on the back chamber includes the back chamber volume determined by two parameters of sectional area and depth；

Step 2, absorption peak quantity determines；

According to all sound absorption peaks of the m unit that absorbs sound in target frequency bands (f_A~f_B) domestic demand continuous uniform distribution requirement, obtain To number of peaks n=(f_A-f_B)/Δ B, wherein Δ B is peak bandwidth；

Step 3, absorptive unit structural parameters determine；

First, the structural parameters of a sound absorption unit are determined, so that its single order crest frequency is f_AAnd phase in target frequency bands The high-order crest frequency answered, then designs other units, according to the quantity s of high-order peak values all in target frequency bands, is absorbed sound The quantity m=n-s of unit；

Second, in the identical situation of holding unit sectional area, the back chamber depth for successively obtaining sound absorption unit i is as follows,

Wherein, the value range of i is 1 to m, and s ' is the high-order number of peaks that existing unit provides, and range arrives s, l for 0₁For The back chamber thickness of first sound absorption unit, l_iFor the back chamber thickness of the i-th sound absorption unit；High-order peak value is successively by determining sound absorption unit It provides.

Step 4, the space folding arrangement of absorptive unit；

The absorptive unit continuous and parallel determined is arranged, in the design thickness of sound absorption structure, by adjacent sound absorption list The biggish sound absorption unit back chamber of thickness carries out space folding in member, and rear end bending extends to below the lesser sound absorption unit of thickness.

Preferably, absorb sound unit single order crest frequency and the hole dimension of microperforated panel and back chamber size it is related, perforation Diameter is smaller, and equivalent mass is bigger, and crest frequency is lower；Penetration depth is bigger, i.e. the thickness of microperforated panel is bigger, peak value frequency Rate is lower；The punching rate of perforation is smaller, and crest frequency is lower；Cavity volume is bigger, and equivalent stiffness is smaller, and sound absorption peak value is to low frequency It is mobile；

The peak bandwidth of sound absorption unit is mainly related with hole dimension and the sound absorption quantity m of unit, and penetration hole diameter is smaller, resistance Buddhist nun's effect is more obvious, and peak bandwidth is wider；Penetration depth is bigger, and peak bandwidth is wider；The element number that absorbs sound is more, peak strip Width is gradually reduced.

Compared with prior art, the invention has the following beneficial technical effects:

Sound absorption structure provided by the invention is forming multiple peak bandwidths by the way that multiple and different sound absorption units is arranged Meanwhile the high-order peak value that joined part of sound absorption unit is continuously absorbed sound, and obtains the sound absorption peak value of different frequency, finally Realize continuous sound sucting band；And each unit can be mentioned under the premise of not increasing structural thickness by space folding The multiple peak values supplied are utilized, and peak bandwidth is wider, structure wide band sound absorption is further increased, thus in limited size range It is interior, it realizes expansion and combination to bandwidth, is of great significance for the engineer application of structure.

Detailed description of the invention

Fig. 1 is the structural schematic diagram of sound absorption structure described in present example 1.

Fig. 2 is the front side schematic diagram of sound absorption structure internal structure described in present example 1.

Fig. 3 is the back side schematic diagram of sound absorption structure internal structure described in present example 1.

Fig. 4 is the Y-axis negative direction cross-sectional view of sound absorption structure internal structure described in present example 1.

Fig. 5 is that acoustic absorptivity is tested in the experiment of sound absorption structure described in present example 1.

Fig. 6 is the schematic diagram of internal structure of sound absorption structure described in present example 2.

In figure: the 1~8: the first to the 8th sound absorption unit, 9: structural framing, 10: microperforated panel, 11: back chamber, 12: between unit Partition.

Specific embodiment

Below with reference to specific embodiment, the present invention is described in further detail, it is described be explanation of the invention and It is not to limit.

The present invention problem narrow for low frequency range noise Absorber Bandwidth in air, it is special by the wideband using microperforated panel Property and space folding profile material low frequency characteristic devise the small size multiple-unit coupling broad band low frequency sound absorption structure comprising 4-12 sound absorption unit being continuously arranged side by side, the sound absorption unit are made of microperforated panel 10 and back chamber 11, microperforated panel 10 are arranged in the open end of back chamber 11, and the microperforated panel 10 of all sound absorption units is coplanar with；By adjusting 10 He of microperforated panel The parameter of chamber 11 is carried on the back, each unit has multiple sound absorption peaks, and compared to Helmholtz resonator structure, the band of peak value Width is wider；Wherein, the parameter of microperforated panel 10 includes the punching rate on diameter, depth and the microperforated panel 10 of perforation；Carry on the back chamber 11 Parameter include carry on the back chamber 11 volume, determined by two parameters of sectional area and depth.On this basis, multiple stringent by designing Coupling unit, so that the single order peak value of sound absorption unit and high-order peak value uniformly continuous as far as possible are distributed, thus in middle low-frequency range It is interior to form a continuous multi-peak sound absorption broadband, increase number of peaks and overall wide band sound absorption.It, will simultaneously in structure design The back chamber of the biggish sound absorption unit of thickness carries out space folding, that is, its rear end is extended under the lesser sound absorption unit of thickness Side, makes full use of structure space, reduces the general thickness of structure.Finally, by strictly adjusting parameter and the peak value position of each unit It sets, when structural thickness is 6cm, continuous sound absorption can be realized within the scope of 550Hz-2500Hz, and its average sound absorption coefficient is up to 90% or more.

There is equally distributed perforation, the section for carrying on the back chamber can be square, rectangle, circle on the microperforated panel 10 Shape, triangle and other shapes etc..

The sound absorption structure further includes the structural framing 9 formed by unit interval plate 12, is used for each sound absorption unit Keep apart, avoids the generation of acoustic power flow phenomenon；Frame is processed using modes such as 3D printing or molds, and structural framing 9 is arranged There is closed shell, one end that shell corresponds to microperforated panel 10 is provided with to be open correspondingly with microperforated panel 10.

Each sound absorption unit of sound absorption structure of the present invention can be equivalent at mass-spring system, and wherein equivalent mass derives from Air quality in the perforation of microperforated panel 10, equivalent damping derives from the damping of perforated wall, and equivalent spring rigidity is Carry on the back the air rigidity in intracavitary portion；By the structural parameters for adjusting different sound absorption units, so that it may obtain the sound absorption peak of different frequency Value, finally realizes continuous sound sucting band.

Absorb sound unit single order peak value and high-order peak value be as caused by the first order resonant and high order resonance mode of system, The relationship of crest frequency can be f with approximate representation_p=(2p-1) × f₁, p is the order of peak value；It can be seen that sound absorption unit single order Crest frequency is lower, and corresponding high-order crest frequency is lower.

All sound absorption peaks of m sound absorption unit are in target frequency bands (f_A~f_B) distribution of domestic demand continuous uniform, number of peaks n= (f_A-f_B)/Δ B, wherein Δ B is peak bandwidth；The structural parameters for determining a sound absorption unit, so that its single order crest frequency is f_AAnd corresponding high-order crest frequency in target frequency bands, other units are then designed, according to high-order peak values all in target frequency bands Quantity s, that is, can determine sound absorption unit quantity, i.e. m=n-s；Back chamber thickness l is the most straight of adjusting sound absorption unit crest frequency The parameter connect, in the identical situation of holding unit sectional area, absorb sound unit i back chamber depth its can be by formulaWherein s ' is the high-order number of peaks that existing unit provides, l₁For the back of the first sound absorption unit Chamber thickness, l_iFor the back chamber thickness of the i-th sound absorption unit；Side positioned opposite between the sound absorption peak value of sound absorption unit and the unit that absorbs sound Formula is unrelated, and each unit that absorbs sound can be with a line or plurality of rows, as long as close continuous arrangement.Sound absorption unit in this method is suitable Sequence and final no corresponding relationship that puts in order, when determination sequence for the unit that absorbs sound, are determined according to sound absorption peak value, and first really The thickness of fixed sound absorption unit is maximum, is then sequentially reduced according to determining sequence thickness；Absorb sound unit when putting in order according to Thickness cooperation determines.

The single order crest frequency of sound absorption unit is mainly related with the hole dimension of microperforated panel 10 and back 11 size of chamber, perforation Diameter is smaller, and equivalent mass is bigger, and crest frequency is lower；Penetration depth is bigger, i.e. the thickness of microperforated panel is bigger, peak value frequency Rate is lower；The punching rate of perforation is smaller, and crest frequency is lower；Cavity volume is bigger, and equivalent stiffness is smaller, and sound absorption peak value is to low frequency It is mobile.

The peak bandwidth of sound absorption unit is mainly related with hole dimension and the sound absorption quantity m of unit, and penetration hole diameter is smaller, resistance Buddhist nun's effect is more obvious, and peak bandwidth is wider；Penetration depth is bigger, and peak bandwidth is wider；The element number that absorbs sound is more, peak strip Width is gradually reduced.

The perforation of the microperforated panel 10 of sound absorption unit should be uniformly distributed, and shape can round, rectangular, triangle or ellipse Shape etc., when perforation is non-circular, diameter refers to the circumscribed circle diameter of perforation, that is, the maximum width perforated, the number of perforation Amount is more than or equal to 1；Penetration hole diameter suggestion be 0.5mm~1mm, it should be noted that when hole diameter is too small (be less than 0.5mm) When, not only difficulty of processing increases, but also is unfavorable for engineer application due to easily blocking, when hole diameter is too big (being greater than 1mm) When, peak bandwidth can reduce, and high-order sound absorption peak value can decline even disappearance；Punching rate of perforating can be 1%~15%；For Guarantee structural strength, it can be 0.5mm~2mm that plate thickness, which is not easy too thin,.

11 sectional area of back chamber of sound absorption unit can be 10mm × 10mm~100mm × 100mm, when sectional area is too small (small In 10mm × 10mm) when, the damping carried on the back on 11 wall surface of chamber can destroy structure sound absorbing performance and have an impact, and cannot reach expected effect Fruit；The back chamber 11 of each unit can have different sectional areas；Back chamber 11 can have different shapes, such as square, square Shape, circle and other shapes etc.；Structure design when, the back chamber 11 of larger thickness is folded, rear end extend to thickness compared with Small 11 lower section of back chamber, to make full use of structure space, minimizes structure general thickness.

Partition 12 between each unit constitutes structural framing 9, should have certain rigidity, avoids generating acoustic power flow Effect impacts the target peak frequency of unit.Structural framing 9 and 11 material of microperforated panel can mould for metal, hard Material and resin etc..

Sound absorption structure provided by the invention has compared with traditional structure or material to have an enormous advantage, when its with a thickness of When (direction z in Fig. 1) 6cm, there can be up to 90% or more consecutive mean within the scope of middle low frequency 550Hz-2500Hz Acoustic absorptivity.The suggestion value range of element number m is 4~12, when element number is greater than 12, will lead to the suction of each unit Vocal cords width narrows, and is unfavorable for the formation in broadband；And element number less than 4 when, overall sound sucting band is relatively narrow or frequency band among There is low ebb, satisfied continuous wide band can not be obtained.

Example 1

Sound absorption structure is made of 8 units, and the back chamber sectional dimension of each unit is 10mm × 10mm, the thickness of microperforated panel Degree is 1mm, and for partition 12 with a thickness of 2mm, other parameters are as shown in table 1 in structural framing 9.In order to reduce structural thickness, chamber will be carried on the back Thicker the second sound absorption unit 2, third sound absorption unit the 3, the 7th sound absorption unit 7 and the 8th sound absorption unit 8 carries out at space folding Second sound absorption unit 2 is extended to the lower section of the first sound absorption unit 1 by reason respectively, and third sound absorption unit 3 is extended to the 4th sound absorption 8th sound absorption unit 8 is extended to the lower section of the 6th sound absorption unit 6 by the lower section of unit 4, and the 7th sound absorption unit 7 is successively extended To the lower section of the 8th sound absorption unit the 8, the 6th sound absorption unit 6 and the 5th sound absorption unit 5.The structure uses 3D printing integration system Make, material is photosensitive resin or toughened resin etc..

Each sound absorption unit design parameter of table 1.

Note: d is the penetration hole diameter of microperforated panel, and φ is the punching rate of perforation, and l is the depth for carrying on the back chamber.

As shown in figure 5, for the actual measurement acoustic absorptivity in the preferred embodiment of the invention.It can be seen that the structure is in frequency range 550Hz~2500Hz obtains the broadband that a continuous almost Perfect absorbs.The sound sucting band is made of 10 sound absorption peak values, Wherein there are two the second order peak values that peak value is the 7th sound absorption unit 7 and third sound absorption unit 3, it can be seen that the presence of second order peak value Fabric bandwidths are increased 25% or so.In fact, there is also the high-order peak values of other units at higher frequency, only by In the discreteness of its frequency, high-order peak value cannot be continuously distributed in high-frequency range, therefore can not form continuous broadband.It can be with Certainly, if the quantity of adding unit, more peak values can be introduced, then the range in broadband can widen, and can cover More high-orders sound absorption peak values.

Example 2

Sound absorption structure is made of 5 sound absorption units in the present invention preferred embodiment, and all units are arranged to a column.Equally, In order to save space, the thicker unit of chamber will be carried on the back and folded, extended to below relatively thin unit.Sound absorption unit d is extended to Absorb sound unit e lower section, by absorb sound unit b successively extend to sound absorption unit c and absorb sound unit d lower section, will sound absorption unit a according to The secondary lower section for extending to sound absorption unit b, sound absorption unit c, sound absorption unit d and the unit e that absorbs sound.

Above-described specific embodiment has carried out further detailed description to the purpose of the present invention, technical solution, But simultaneously the scope of protection of the present invention is not limited, and all within the spirits and principles of the present invention, any modification for being made equally is replaced It changes, improve, should all be included in the protection scope of the present invention.