CN-119920227-B - Acoustic structure with low frequency and broadband noise reduction and design method of acoustic structure

CN119920227BCN 119920227 BCN119920227 BCN 119920227BCN-119920227-B

Abstract

The invention belongs to the technical field of acoustics, and discloses an acoustic structure with low frequency and broadband noise reduction and a design method of the acoustic structure, wherein the acoustic structure comprises a plurality of acoustic structural members and inserts, at least one insert is arranged in the acoustic structural members in a penetrating way, on the same embedded piece, acoustic structural parts communicated with openings at two ends of the embedded piece are arranged in pairs and form a first primitive together with the embedded piece, the acoustic structural parts which are not communicated with the embedded piece are second primitives, and the first primitive and the second primitive are arranged in parallel. Compared with the prior art, when the acoustic wave passes through the acoustic structural members arranged in pairs, the coupling resonance generated in the acoustic structural members can widen the silencing frequency band at a certain resonance frequency in a low-frequency range, the added inserts can enable the acoustic structural members to generate new silencing frequency bands, the weak coupling effect existing between the parallel elements can further widen the silencing frequency bands, and finally, the silencing and noise reducing effects of low frequency and wider band are achieved.

Inventors

WANG WENQIN
SUN XIAOFENG
YU LANG
HE XUETING
SUN XIAOLONG
ZHU LIANPING

Assignees

上海飞机制造有限公司

Dates

Publication Date: 20260508
Application Date: 20231031

Claims (5)

1. The low-frequency broadband noise reduction acoustic structure is characterized by comprising a plurality of acoustic structural members (1) and an embedded part (2), wherein a resonance cavity is formed in each of the acoustic structural members (1), at least one micropore (111) communicated with the resonance cavity is formed in each of the acoustic structural members (1), each of the embedded part (2) is of a hollow structure with two open ends, at least one embedded part (2) is arranged in each of the acoustic structural members (1) in a penetrating manner, the acoustic structural members (1) communicated with the openings at the two ends of the embedded part (2) are arranged in pairs on the same embedded part (2), a first primitive (100) is formed together with the embedded part (2), at least one acoustic structural member (1) which is not communicated with the embedded part (2) is arranged between the two acoustic structural members (1), each acoustic structural member (1) which is not communicated with the embedded part (2) is a second primitive (200), and the first primitive (200) and the second primitive (200) are arranged in parallel; The acoustic structural member (1) comprises a through hole panel (11) and a structural member body (12), wherein the structural member body (12) is a hollow shell with a single side opening, at least one connecting notch (121) matched with the shape of the embedded piece (2) is formed in the structural member body (12), the through hole panel (11) is covered at the opening of the structural member body (12) to form the resonance cavity, and the micropore (111) is formed in the through hole panel (11); the porosity of the through hole panels (11) of the two acoustic structural members (1) communicated with the two ends of the insert (2) is the same; -the acoustic structure (1) in communication with the insert (2) and the through hole panel (11) of the acoustic structure (1) not in communication with the insert (2) being different in porosity; The end of the insert (2) extends in the resonance chamber of the acoustic structure (1) in communication with the insert (2), but does not abut the inner wall of the resonance chamber; when a plurality of the inserts (2) are arranged in the acoustic structural members (1) in a penetrating way, the inserts (2) have the same or different cross-sectional shapes.
2. The low frequency, broadband noise reducing acoustic structure according to claim 1, characterized in that the cross-sectional shape of the micro-holes (111) is circular, or elliptical, or polygonal; The cross section of the resonance cavity is polygonal or circular; The longitudinal section of the insert (2) is polygonal, semicircular or semi-elliptical.
3. A method of designing an acoustic structure for designing a low frequency, broadband noise reducing acoustic structure according to any one of claims 1-2, comprising the steps of: s1, obtaining the structural sizes of a plurality of acoustic structural members (1) and the number and the diameter of micropores (111) formed in the acoustic structural members (1), and generating a structural model of the combination of the acoustic structural members (1); s2, constructing a sound absorption function of a required audio frequency section according to the structural model; S3, based on the sound absorption function, a required sound absorption spectrum is formulated according to design requirements, a dimension parameter of the embedded piece (2) meeting the sound absorption requirement is found by utilizing an optimization algorithm, the embedded piece (2) is combined with the acoustic structural member (1) in the structural model, and an integral model of the low-frequency and broadband noise reduction acoustic structure is generated; And S4, further adjusting the size parameters of the integral model, and the number and the positions of the inserts (2) so that the low-frequency and broadband noise reduction acoustic structure meets the design requirement.
4. A method of designing an acoustic structure according to claim 3 wherein in step S3, the optimization algorithm is a reinforcement learning algorithm or a genetic algorithm.
5. A method of designing an acoustic structure according to claim 3, wherein in step S4, the dimensional parameters that can be used for adjustment in the overall model include the structural dimensions of a plurality of the acoustic structural members (1), the number, diameter and arrangement of the micro-holes (111) formed in the acoustic structural members (1), and the dimensional parameters of the inserts (2).

Description

Acoustic structure with low frequency and broadband noise reduction and design method of acoustic structure Technical Field The invention relates to the technical field of acoustics, in particular to an acoustic structure with low frequency and broadband noise reduction and a design method of the acoustic structure. Background Aircraft engine noise control is critical to meeting noise compliance criteria and improving cabin comfort. For noise generated by the engine, besides active noise control and geometric shape optimization noise reduction, damping materials can be paved in an air inlet channel, a thrust reverser and a tail spray system to perform passive noise reduction. The damping material adopted at first is mainly porous sound absorption material, then is improved into an acoustic structure with single degree of freedom, and along with development of scientific technology, various aircraft manufacturers and engine suppliers sequentially develop a plurality of noise reduction structure researches, so that a net cap type acoustic structure is provided, and the aim of improving the noise elimination and reduction capacity of different noise frequency bands is achieved. However, the net cap structure in the acoustic structure has the problems of large gluing difficulty coefficient, long product development period, high cost and the like caused by repeated trial and error in industrial production, and also has the condition of large effective acoustic performance regulation difficulty caused by easy breakage, falling off and the like under the influence of the rotation vibration of the engine blade. With the use of high bypass ratio engines and the development of more severe noise airworthiness standards, the structure cannot further meet the actual requirements of the aircraft in terms of comfort, silence and the like. In order to overcome the long-standing problems, the design of the acoustic structure with the characteristics of sound absorption frequency bandwidth, multiple resonance sound absorption peaks, strong overall mechanical property and the like becomes a main development trend of the novel sound liner of the sound attenuation nacelle. Disclosure of Invention The invention aims to provide an acoustic structure with low frequency and broadband noise reduction and a design method of the acoustic structure, and aims to widen a low frequency noise elimination frequency band and maintain higher mechanical properties while enhancing the low frequency noise reduction capability. To achieve the purpose, the invention adopts the following technical scheme: In one aspect, the low-frequency and broadband noise reduction acoustic structure comprises a plurality of acoustic structural members and an embedded part, wherein a resonance cavity is formed in each of the plurality of acoustic structural members, at least one micropore communicated with the resonance cavity is formed in each of the plurality of acoustic structural members, each of the plurality of acoustic structural members is of a hollow structure with two open ends, at least one embedded part is arranged in a penetrating mode, on the same embedded part, the acoustic structural members communicated with the two open ends of the embedded part are arranged in pairs and form a first primitive together with the embedded part, at least one acoustic structural member which is not communicated with the embedded part is arranged between the two acoustic structural members communicated with the embedded part, the acoustic structural members which are not communicated with the embedded part are second primitives, and the first primitive and the second primitive are arranged in parallel. Optionally, the acoustic structure includes through-hole panel and structure body, the structure body is unilateral open hollow shell, at least one with insert appearance assorted connection breach has been seted up on the structure body, the through-hole panel lid is established the uncovered department of structure body, in order to constitute the resonance cavity, the micropore is seted up on the through-hole panel. Optionally, the porosity of the through hole panels of the two acoustic structures in communication with both ends of the insert is the same. Optionally, the acoustic structure in communication with the insert and the through-hole panel of the acoustic structure not in communication with the insert are different in porosity. Optionally, an end of the insert extends in the resonance chamber of the acoustic structure in communication with the insert, but does not abut an inner wall of the resonance chamber. Optionally, when a plurality of the inserts are provided in a plurality of the acoustic structural members, the plurality of inserts have the same or different cross-sectional shapes. Optionally, the cross-sectional shape of the micropores is circular, or elliptical, or polygonal; The cross section of the resonance cavity is polygonal or circular; the l