阅读说明：本技术 一种低频宽带平板吸声结构 (Low-frequency broadband flat plate sound absorption structure ) 是由 解龙翔 卢明辉 黄唯纯 钟雨豪 于 2020-11-30 设计创作，主要内容包括：本发明公开了一种低频宽带平板吸声结构,包括框架、固定设于框架上下两侧的前面板和后背板、以及由框架、前面板和后背板围合而成的用于吸收低频噪声的吸声体；前面板上设有若干吸声孔,吸声孔一侧朝向声源,另一侧与吸声体相连。吸声体由若干平行设置在框架内的隔板组成,隔板的一端与框架一侧内壁固定,另一端与框架另一侧内壁间隙配合；隔板将框架内空间分隔成蛇形通道,通道上设有用于隔开的框架内壁,相邻框架内壁间的通道形成MIE型共振腔。本发明结构紧凑,质量轻,面密度小,低频吸声频带较宽,低频吸声性能良好。(The invention discloses a low-frequency broadband flat plate sound absorption structure which comprises a frame, a front panel and a rear back panel which are fixedly arranged on the upper side and the lower side of the frame, and a sound absorber which is formed by enclosing the frame, the front panel and the rear back panel and is used for absorbing low-frequency noise; the front panel is provided with a plurality of sound absorption holes, one side of each sound absorption hole faces to a sound source, and the other side of each sound absorption hole is connected with the sound absorber. The sound absorber consists of a plurality of partition plates which are arranged in the frame in parallel, one end of each partition plate is fixed with the inner wall of one side of the frame, and the other end of each partition plate is in clearance fit with the inner wall of the other side of the frame; the partition board divides the space in the frame into snake-shaped channels, the channels are provided with inner walls of the frame for separation, and the channels between the inner walls of the adjacent frames form an MIE type resonant cavity. The invention has compact structure, light weight, small surface density, wide low-frequency sound absorption frequency band and good low-frequency sound absorption performance.)

1. A low frequency broadband flat plate sound absorption structure is characterized in that: the sound absorber comprises a frame (2), a front panel (1) and a back panel (3) which are fixedly arranged on the upper side and the lower side of the frame (2), and a sound absorber (4) which is formed by enclosing the frame (2), the front panel (1) and the back panel (3) and is used for absorbing low-frequency noise; the front panel (1) is provided with a plurality of sound absorption holes (6), one side of each sound absorption hole (6) faces towards a sound source, and the other side of each sound absorption hole is connected with the sound absorber (4).

2. The low frequency broadband flat panel sound absorbing structure of claim 1, wherein: the sound absorber (4) is composed of a plurality of partition plates (41) which are arranged in parallel in the frame (2), one end of each partition plate (41) is fixed with the inner wall of one side of the frame (2), and the other end of each partition plate is in clearance fit with the inner wall of the other side of the frame (2); the space in the frame (2) is divided into a snake-shaped channel by the partition plate (41), frame inner walls (5) for separation are arranged on the channel, and an MIE-type resonant cavity (7) is formed by the channels between the adjacent frame inner walls (5).

3. The low frequency broadband flat panel sound absorbing structure of claim 2, wherein: the MIE type resonant cavity (7) is correspondingly provided with a sound absorption hole (6) connected with the MIE type resonant cavity, and the cross section of the sound absorption hole (6) is circular or quadrilateral.

4. A low frequency broadband flat panel sound absorbing structure according to claim 2 or 3, wherein: the sound absorption frequency of the MIE type resonant cavity (7) is reduced along with the increase of the distance between the inner walls (5) of the frame.

5. The low frequency broadband flat panel sound absorbing structure of claim 2, wherein: the number of the MIE type resonant cavities (7) is 3-25.

6. The low frequency broadband flat panel sound absorbing structure of claim 2, wherein: the partition plates (41) are arranged at equal intervals, and the interval between every two adjacent partition plates (41) is 4-20 mm.

7. The low frequency broadband flat panel sound absorbing structure of claim 1, wherein: the sound absorption structure is 50-300 mm in length, 50-200 mm in width and 30-250 mm in depth.

8. The low frequency broadband flat panel sound absorbing structure of claim 1, wherein: the frame (2) is connected with the front panel (1) and the back panel (3) through ultrasonic welding.

Technical Field

The invention relates to a sound absorption structure, in particular to a low-frequency broadband flat plate sound absorption structure.

Background

With the development of modern society, the quality of life is continuously improved, and environmental problems, especially noise problems, are becoming more serious. In recent years, the traffic facilities in China are gradually improved, the traffic transportation is developed at a high speed, the influence of environmental noise is gradually enlarged, the problem of traffic noise is increasingly prominent, and the treatment of noise pollution becomes a problem to be solved in a global scope. Expressway, underground railway, high-speed railway and air transportation are the marks of urban modernization, but the noise problem of modern vehicles in the process of high-speed running always influences normal work, study and rest of people. The passing noise has the characteristics of low frequency, temporality, concentration and the like, so that the passing noise is difficult to control. In view of this, it is very important to develop a low-frequency broadband flat sound absorption structure to improve the living environment and the living quality of people.

At present, the control and treatment of noise mainly adopt sound insulation barriers in China. The traditional sound insulation barrier is generally a combined structure of a double-layer steel plate and a porous sound absorption material added in the double-layer steel plate, the technical scheme has poor low-frequency sound absorption effect, and the whole sound insulation performance is general. The novel low-frequency sound absorption structure generally adopts a local resonance and porous material combined sound absorption mechanism, has a certain absorption effect on low-frequency passing noise, but has larger structure thickness, general low-frequency sound absorption performance and narrower application range. For example, chinese patent publication No. CN1512482 discloses a sound-absorbing material, a method for manufacturing the same, and an application thereof, wherein the sound-absorbing material has a wavy fold, and a convex surface of the wavy fold has a fine gap; the sound absorption principle of the technical scheme is the same as that of a micro-perforated plate, and the sound absorption performance is similar to that of the micro-perforated plate, so that the sound absorption bandwidth is narrow, and the low-frequency sound absorption performance is poor. Chinese patent publication No. CN1219989A discloses a track noise control device comprising a sound absorbing panel mounted on a rail of a track, the panel being supported on the rail by resilient members and self-supporting across a space between the rails; the technical scheme absorbs passing noise from a train through the combined action of the sound-deadening resonant cavity and the porous light building material particles, but is limited by the height of a rail, the thickness of the structure is thinner, and the volume of the sound-deadening resonant cavity is smaller, so that the low-frequency sound absorption performance is poorer. In view of this, it is very important to control and manage the environmental noise to develop a high-efficient low-frequency broadband sound absorption structure.

Disclosure of Invention

The purpose of the invention is as follows: the invention aims to provide a flat plate sound absorption structure for low-frequency broadband sound absorption.

The technical scheme is as follows: the invention relates to a low-frequency broadband flat plate sound absorption structure which comprises a frame, a front panel and a rear back panel which are fixedly arranged on the upper side and the lower side of the frame, and a sound absorber which is formed by enclosing the frame, the front panel and the rear back panel and is used for absorbing low-frequency noise; the front panel is provided with a plurality of sound absorption holes, one side of each sound absorption hole faces to a sound source, and the other side of each sound absorption hole is connected with the sound absorber.

Furthermore, the sound absorber consists of a plurality of partition plates which are arranged in parallel in the frame, one end of each partition plate is fixed with the inner wall of one side of the frame, and the other end of each partition plate is in clearance fit with the inner wall of the other side of the frame; the partition plate divides the space in the frame into snake-shaped channels, the channels are provided with frame inner walls for separation, and the channels between the adjacent frame inner walls form an MIE type resonant cavity. Meanwhile, in order to ensure the stability of the sound absorption process, each MIE type resonant cavity is correspondingly provided with a sound absorption hole connected with the MIE type resonant cavity, the number of the sound absorption holes is ensured to be matched with the number of the MIE type resonant cavities of the sound absorber, and the cross section of each sound absorption hole is circular or quadrilateral.

Further, the sound absorption frequency of the MIE-type resonance cavity is reduced with the increase of the distance between the inner walls of the frame, because the MIE-type resonance cavity is a Fabry-Perot (abbreviated as FP) like resonance structure, the sound absorption performance of the MIE-type resonance cavity is related to the cavity depth, the cavity cross-sectional shape and the cavity volume, and the design of the sound absorption coefficient and the sound absorption frequency band can be realized by adjusting the cavity volume. Generally, the number of the MIE type resonant cavities is 3 to 25, and the number of the resonant cavities is preferably 9 in consideration of the low frequency acoustic impedance matching problem.

The baffles are arranged at equal intervals, the interval between every two adjacent baffles is 4-20 mm, preferably 4mm, on the premise that the integral rigidity of the structure is guaranteed, the low-frequency sound absorption performance of the flat sound absorption structure is improved, and the low-frequency sound absorption frequency band is widened.

Further, the length of the sound absorption structure is 50-300 mm, the width of the sound absorption structure is 50-200 mm, and the depth of the sound absorption structure is 30-250 mm; the frame is connected with the front panel and the back panel through ultrasonic welding.

The working principle is as follows: when the sound waves vertically enter the front panel of the structure, a part of the sound waves are reflected due to the action of the panel, so that the transmitted sound energy is weakened, and the sound insulation performance of the flat sound absorption structure is improved; meanwhile, a part of sound waves enter the sound absorber through the sound absorption holes, when the incident wavelength is matched with the acoustic impedance of the MIE type resonant cavity, vertical resonance is generated, the sound waves oscillate in the resonant cavity, the friction resistance is overcome, the sound energy is consumed, and the purpose of sound absorption is achieved; meanwhile, sound waves are transmitted in the resonant cavity, and a part of sound energy is consumed due to the slow wave effect, so that the integral sound absorption performance of the structure is improved. Typically, a single MIE-type resonant cavity corresponds to a resonant frequency, absorbing sound waves at the resonant frequency. However, due to the adjacent coupling effect among the resonant cavities, a plurality of coupling resonant frequencies are generated, so that the sound absorption frequency range is widened, and the sound absorption performance of the whole structure is improved.

Has the advantages that: compared with the prior art, the invention has the following remarkable characteristics:

1. the invention has compact integral structure, light weight and small surface density;

2. the low-frequency sound absorption frequency band is wider, and the low-frequency sound absorption performance is good;

3. the sound absorption performance of the invention is related to the structural parameters, the sound absorption frequency band is designed by changing the structural parameters and the sound absorption coefficient is improved, so that the sound insulation performance of the low frequency is ensured to be good, and the invention can widely replace the existing low frequency sound absorption/insulation layer.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a front view of the present invention;

FIG. 3 is a top view of the present invention;

FIG. 4 is a sectional view taken along the line A-A of FIG. 2;

FIG. 5 is a sectional view taken along the line B-B of FIG. 3;

FIG. 6 is a graph of the sound absorption characteristics of the present invention;

fig. 7 is a transmission loss characteristic curve of the present invention.

Detailed Description

The invention is further illustrated by the following examples and figures.

As shown in fig. 1 to 5, the flat panel sound absorbing structure includes a front panel 1, a frame 2, a rear panel 3 and a sound absorber 4 enclosed thereby, which are joined by ultrasonic welding. The flat plate sound absorption structure has the following external dimensions: 128mm (W) X128 mm (D) X30 mm (H); the sound absorber 4 comprises 24 parallel baffles 41, the distance between every two adjacent baffles 41 is 4mm, one end of each baffle 41 is fixed to the inner wall of one side of the frame 2, the other end of each baffle 41 is in clearance fit with the inner wall of the other side of the frame 2, the size of each clearance is 6mm, the baffles 41 divide the space in the frame 2 into serpentine channels, eight frame inner walls 5 are arranged on the channels, the channels between every two adjacent frame inner walls 5 form an MIE-type resonant cavity 7, 9 MIE-type resonant cavities 7 are arranged, and the sound absorber 4 is arranged in a zigzag mode.

As shown in fig. 3, 9 long and narrow rectangular sound-absorbing holes 6 are arranged on the front panel 1, respectively corresponding to 9 MIE-type resonant cavities, and sequentially form a first sound-absorbing hole, a second sound-absorbing hole, a third sound-absorbing hole, a fourth sound-absorbing hole, a fifth sound-absorbing hole, a sixth sound-absorbing hole, a seventh sound-absorbing hole, an eighth sound-absorbing hole and a ninth sound-absorbing hole from top to bottom; the length of the MIE type resonant cavity corresponding to the first sound absorption hole is 429mm, and the noise under 200-205 Hz can be absorbed; the length of the MIE type resonant cavity corresponding to the second sound absorption hole is 408mm, and the MIE type resonant cavity can absorb noise under 210-215 Hz; the length of the MIE type resonant cavity corresponding to the third sound absorption hole is 388mm, and noise under 221-226 Hz can be absorbed; the length of the MIE type resonant cavity corresponding to the fourth sound absorption hole is 369mm, and the noise under 232-238 Hz can be absorbed; the length of the MIE type resonant cavity corresponding to the fifth sound absorption hole is 350mm, and the noise under 245-251 Hz can be absorbed; the length of the MIE type resonant cavity corresponding to the sixth sound absorption hole is 333mm, and the noise under 258-265 Hz can be absorbed; the length of the MIE type resonant cavity corresponding to the seventh sound absorption hole is 317mm, and the noise under 271-277 Hz can be absorbed; the length of the MIE type resonant cavity corresponding to the eighth sound absorption hole is 300mm, and the noise under 286-290 Hz can be absorbed; the length of the MIE type resonant cavity corresponding to the sound absorption hole No. nine is 208.5mm, and the noise under 296-300 Hz can be absorbed. Meanwhile, due to the adjacent coupling effect between adjacent resonant cavities, the sound absorption frequency range is widened to 200-300 Hz.

Referring to fig. 6 to 7, finite element simulation analysis is performed on the panel sound absorption structure to obtain the sound absorption characteristic and the transmission loss characteristic of the panel sound absorption structure. Under the condition that the total thickness of the structure is 30mm, the low-frequency sound absorption performance of the flat sound absorption structure is good, and the average sound absorption coefficient of the structure in a designed frequency band of 200-300 Hz is about 0.67; meanwhile, the sound insulation performance of the whole flat sound absorption structure is good, and the average sound insulation quantity of the structure in a designed frequency band of 200-300 Hz is about 25 dB.

The flat sound absorption structure of the embodiment is used for controlling noise in a carriage of a high-speed train, and replaces the existing low-frequency sound absorption/insulation layer with the flat sound absorption structure. The flat sound absorption structure has good low-frequency sound absorption performance, and can effectively reduce reverberation noise in a carriage of a train in the high-speed running process; meanwhile, the flat sound absorption structure has good low-frequency sound insulation performance, can effectively isolate the passing noise of a train in the high-speed running process, and improves the riding comfort of passengers.