Adjustable acoustic component for assembly with a multicellular body

Abstract

The invention relates to an acoustic component (120) intended to be assembled with a multicellular body (130), the acoustic component (120) comprising a plurality of hollow acoustic elements (121) having a shape that narrows gradually between a base (121a) and an apex (121b), the bases (121a) of the hollow acoustic elements (121) being connected to one another by bridges (122), the acoustic component (120) being characterized in that the bridges (122) have at least one undulation.

Description

Description Title of the invention: Adjustable acoustic component for assembly with a multicellular body Technical Field

[0001] The present invention relates to the general field of acoustic attenuation structures. More particularly, it relates to acoustic attenuation structures used to reduce noise produced in aircraft engines, such as gas turbines or exhaust systems. Previous technique

[0002] Acoustic attenuation panels typically consist of a surface plate or skin with acoustic permeability to the sound waves to be attenuated, and a solid, reflective plate or skin known as the "closing plate," with a multicellular body sandwiched between these two surfaces. The multicellular body is generally composed of a series of partitions, for example, in a honeycomb pattern, delimiting a plurality of cells. As is well known, such panels form Helmholtz resonators that attenuate sound waves within a specific frequency range, with the height of the cavities allowing selection of the target frequency band. Acoustic attenuation panels of this type are described in US patent 5,912,442 and GB patent 2,314,526. Therefore, the lower the frequency bands to be attenuated, the greater the height of the cavities will need to be.

[0003] These acoustic attenuation panels, limited to simple cell shapes such as NIDA-type honeycomb cells, are not suitable for absorbing very low frequencies due to the required cavity height and resulting bulk. This is particularly true for acoustic attenuation panels used in high-bypass turbojet engines, where the frequencies to be absorbed are between 200 Hz and 400 Hz and where space is limited.

[0004] One solution for handling low frequencies without using an excessively thick multicellular body is to place hollow acoustic elements, such as open truncated cones, within the cells of the multicellular body, as described in document FR 3 082 987. The hollow acoustic elements are typically connected to each other to form a single-piece acoustic component. Such an acoustic component is described, for example, in documents WO 2023 / 089267 A1 and WO 2023 / 052707 A1.

[0005] To manufacture such an acoustic panel, it is therefore necessary to assemble an acoustic component formed by hollow acoustic elements with a multicellular body, so that the hollow acoustic elements are arranged in the cells of the multicellular body.

[0006] However, assembling the acoustic component with the multicellular body can be tricky, and hollow acoustic elements can be difficult to position correctly in the cells of the multicellular body.

[0007] Furthermore, acoustic damping panels can be subject to some humidity. Acoustic components such as those described in documents WO 2023 / 089267 Al and WO 2023 / 052707 Al are not well optimized for fluid evacuation and drainage. Description of the invention

[0008] The present invention aims to overcome the aforementioned drawbacks by providing a solution for easily assembling the acoustic component with the multicellular body. Furthermore, the present invention improves fluid drainage within the acoustic attenuation panel.

[0009] To this end, the invention proposes an acoustic component comprising a plurality of hollow acoustic elements having a shape that gradually narrows between a base and a top, the bases of the hollow acoustic elements being connected to each other by bridges, the acoustic component being characterized in that the bridges have at least one undulation.

[0010] Thus, the undulation(s) of the bridge give it a certain deformability, which allows the distance between the hollow acoustic elements to be adapted. The assembly of the acoustic component with a multi-cell body is thus facilitated, even when assembling with a curved multi-cell body. Furthermore, the connection of the acoustic elements by bridges ensures a non-zero distance between the hollow acoustic elements and the partitions of the multi-cell body. This facilitates the drainage of fluids that could accumulate between the hollow acoustic elements and the partitions of the multi-cell body.

[0011] Each bridge extends between two bases along an extension direction, the undulation extending along the extension direction.

[0012] The acoustic component is intended to be assembled with a multicellular body.

[0013] According to a particular embodiment of the invention, the undulation is formed by at least one fold extending perpendicularly to the direction of extension of the bridge.

[0014] In particular, the invention relates to an acoustic component comprising a plurality of hollow acoustic elements having a shape that gradually narrows between a base and a top, the bases of the hollow acoustic elements being connected to each other by bridges, each bridge extending between two bases along an extension direction, the acoustic component being characterized in that the bridges have at least one fold extending perpendicularly to the extension direction of the bridge.

[0015] According to a first particular embodiment of the invention, at least a portion of the bridges comprises a single fold separating two lateral portions of the bridge, the lateral portions of the bridge extending from the bases to the tops of the hollow acoustic elements.

[0016] This bridge configuration is particularly easy to manufacture and implement.

[0017] According to a second particular embodiment of the invention, at least a portion of the bridges comprises exactly two folds, the first fold separating a first lateral portion of the bridge from a bottom portion of the bridge and the second fold separating a second lateral portion of the bridge from the bottom portion, the lateral portions of bridge extending from the bases to the tops of the hollow acoustic elements.

[0018] This configuration allows for a base portion that provides more stable contact with the multicellular body during assembly.

[0019] According to a third particular embodiment of the invention, at least a portion of the bridges comprises exactly three folds, the first fold separating a first lateral portion of the bridge from a first central portion of the bridge, the second fold separating a second lateral portion of the bridge from a second central portion of the bridge and the third fold separating the first central portion of the bridge from the second central portion of the bridge, the lateral portions of the bridge extending from the bases to the tops of the hollow acoustic elements and the central portions of the bridge extending from the first and second folds to the bases of the hollow acoustic elements.

[0020] This configuration can make it possible to avoid making upper notches on the multicellular body to allow the cooperation of the bridges with the partitions of the multicellular body.

[0021] According to a first variant of the invention, part of the bridges extends along the same first principal direction of the acoustic component and the other part of the bridges extends along a second principal direction of the acoustic component intersecting the first principal direction.

[0022] This results in a good compromise between a flexible and deformable acoustic component thanks to a reduced number of bridges, while retaining a sufficient number of bridges to obtain a robust acoustic component with good cohesion.

[0023] According to a second variant of the invention, all the bridges extend along the same main direction of the acoustic component.

[0024] Such an acoustic component thus takes the form of a strip of acoustic elements arranged in a line, which exhibits excellent deformability and adaptation.

[0025] According to a particular aspect of the invention, two adjacent bases are connected at most by a bridge.

[0026] Thus, the acoustic component exhibits excellent deformability and high adaptability.

[0027] According to another particular aspect of the invention, two adjacent connected bases are linked by a plurality of bridges extending along the same principal direction.

[0028] Thus, the robustness and cohesion of the acoustic component are improved.

[0029] Furthermore, the invention proposes an acoustic panel comprising at least one acoustic component as described above and a multicellular body comprising a plurality of partitions delimiting cells, the hollow acoustic elements of the acoustic component being arranged in the cells of the multicellular body so that the bridges are in contact with the partitions of the multicellular body and the bases of the hollow acoustic elements are spaced away from the partitions of the multicellular body.

[0030] In the first embodiment of the invention, the single fold of the bridges can be in contact with the partitions of the multicellular body.

[0031] In the second embodiment of the invention, the bottom portion of the bridges can be in contact with the partitions of the multicellular body.

[0032] In the third embodiment of the invention, the third fold of the bridges can be in contact with the partitions of the multicellular body. Brief description of the drawings

[0033] [Fig. 1] Figure 1 is a schematic perspective view of an acoustic component comprising bridges according to a first embodiment of the invention assembled with a multicellular body.

[0034] [Fig. 2] Figure 2 is a schematic cross-sectional view of the acoustic component and multicellular body of Figure 1.

[0035] [Fig. 3] Figure 3 is a schematic cross-sectional view of an acoustic component comprising bridges according to a second embodiment of the invention assembled with a multicellular body.

[0036] [Fig. 4] Figure 4 is a schematic cross-sectional view of an acoustic component comprising bridges according to a third embodiment of the invention assembled with a multicellular body.

[0037] [Fig. 5] Figure 5 is a schematic top view of the acoustic component and multicellular body of Figures 1 and 2 according to a first variant of the invention.

[0038] [Fig. 6] Figure 6 is a schematic top view of several acoustic components and a multicellular body according to a second embodiment of the invention.

[0039] [Fig. 7] Figure 7 is a schematic top view of several acoustic components and a multicellular body according to an alternative to the second variant of the invention. Description of the implementation methods

[0040] The present invention relates to an acoustic component comprising a plurality of hollow acoustic elements, each having a shape that gradually narrows between a base and an apex. The bases of the hollow acoustic elements are connected to each other by bridges. According to the invention, the bridges have at least one undulation.

[0041] The bridges can have different specific shapes, according to several embodiments of the invention.

[0042] Figures 1 and 2 illustrate an acoustic component 120 comprising bridges 122 according to a first embodiment of the invention. The acoustic component 120 comprises a plurality of hollow acoustic elements 121, each having a shape that gradually narrows from a base 121a to a top 121b. The hollow acoustic elements 121 extend between the base 121a and the top 121b along a vertical direction DH. The hollow acoustic elements 121 are perforated at their top 121b.

[0043] Figures 1 and 2 illustrate the acoustic component 120 assembled with a multicellular body 130. The multicellular body 130 comprises a plurality of partitions 131 that form a network of ribs, thus delimiting cells 132. Each partition 131 extends between an upper edge 131a and a lower edge 131b. The upper edges 131a of the partitions 131 define a first assembly face 130a of the multicellular body 130. The lower edges 131b of the partitions 131 define a second assembly face 130b of the multicellular body 130. Thus, the cells 132 extend from the first assembly face 130a to the second assembly face 130b of the multicellular body. 130. The cells 132 accommodate the hollow acoustic elements 121. Typically, each cell 132 accommodates a single hollow acoustic element 121. The perforations at the apexes 121b of the acoustic elements 121 allow sound waves to penetrate to the bottom of the cell 132. The acoustic component 120 is configured to be assembled with the multicellular body 130, so as to form a plurality of complete acoustic cells, each formed by a cell 132 of the multicellular body 130 assembled with an acoustic element 121.

[0044] In this first embodiment of the invention, the partitions 131 have upper notches 133 on the upper edges 131a of the partitions 131. The upper notches 133 can be formed by a base and two side walls. The upper notches 133 can have a "U" shape.

[0045] The partitions 131 may have lower notches 134 formed at the lower edges 131b of the partitions 131. These lower notches 134 facilitate the evacuation of fluids.

[0046] Each bridge 122 connects the base 121a of a first hollow acoustic element 121 at the base 121a of a second hollow acoustic element 121. Each bridge 122 connects the base 121a of a first hollow acoustic element 121 to the base 121a of a second hollow acoustic element 121 along a proper extension direction DEI.

[0047] In this first embodiment of the invention, the bridges 122 comprise a single fold 123. The fold 123 extends perpendicularly to the direction of height DH. The fold 123 extends perpendicularly to the extension direction DEI of the bridge 122. The bridges 122 are formed by a first lateral portion 122a and a second lateral portion 122b separated by the fold 123. The lateral portions 122a and 122b extend from the bases 121a of the hollow acoustic elements 121 to the fold 123. Thus, the bridges 122 according to the first embodiment of the invention have a "V" shape. The lateral portions 122a and 122b extend from the bases 121a of the hollow acoustic elements 121 towards the apexes 121b of the hollow acoustic elements 121. In particular, the first lateral portion 122a extends from the base 121a of the first hollow acoustic element 121 connected by the bridge 122 and the second lateral portion 122b extends from the base 121a of the second hollow acoustic element 121 connected by the bridge 122.

[0048] Preferably, the bridges 122 are located between the surface comprising the bases 121a of the hollow acoustic elements 121 and the surface comprising the vertices 121b of the hollow acoustic elements 121. Thus, the bridges 122 project towards the vertices 121b of the hollow acoustic elements 121 and not project away from the vertices 121b of the hollow acoustic elements 121.

[0049] Preferably, the bridges 122 have symmetry with respect to a plane including the fold 123. Thus, the first lateral portion 122a and the second lateral portion 122b have the same length.

[0050] The lateral portions 122a and 122b and the fold 123 thus form a wave. The fold 123 allows the angle between the first lateral portion 122a and the second lateral portion 122b to be varied. Therefore, the length of the bridge 122 along its extension direction DEI can be adjusted. Consequently, the distance between the two hollow acoustic elements 121 connected by the bridge 122 can be adjusted to facilitate the assembly of the acoustic component 120 with the multicellular body 130.

[0051] When the acoustic component 120 is assembled in the multicellular body 130, the bridges 122 cooperate with the upper notches 133 of the partitions 131. The fold 123 is in contact with the upper notches 133. In particular, the fold 123 is in contact with the bottom of the upper notches 133.

[0052] The hollow acoustic elements 121 are not in contact with the multicellular body 130. Thus, the bases 121a of the hollow acoustic elements 121 are maintained at a non-zero distance from the partitions 131 of the multicellular body 130. The apexes 121b of the hollow acoustic elements 121 are maintained at a non-zero distance from the partitions 131 of the multicellular body 130. The acoustic component 120 is connected to the multicellular body 130 only by the bridges 122. Consequently, fluid drainage is facilitated.

[0053] Figure 3 illustrates an acoustic component 220 comprising bridges 222 according to a second embodiment of the invention. The acoustic component 220 comprises a plurality of hollow acoustic elements 221, each having a shape that gradually narrows from a base 221a to a top 221b. The hollow acoustic elements 221 extend between the base 221a and the top 221b along a height direction DH.

[0054] Figure 3 illustrates the acoustic component 220 assembled with the multicellular body 130 as described in the first embodiment.

[0055] Each bridge 222 connects the base 221a of a first hollow acoustic element 221 at the base 221a of a second hollow acoustic element 221. Each bridge 222 connects the base 221a of a first hollow acoustic element 221 to the base 221a of a second hollow acoustic element 221 along a proper extension direction DEI.

[0056] In this second embodiment of the invention, the bridges 222 comprise a first fold 223a and a second fold 223b. The folds 223a and 223b extend perpendicularly to the vertical direction DH. The folds 223a and 223b extend perpendicularly to the horizontal direction DEI of the bridge 222. The bridges 222 are formed by a first lateral portion 222a, a second lateral portion 222b, and a bottom portion 222c. The lateral portions 222a and 222b extend from the bases 221a of the hollow acoustic elements 221 to the bottom portion 222c. The first lateral portion 222a is separated from the bottom portion 222c by the first fold 223a. The second lateral portion 222b is separated from the bottom portion 222c by the second fold 223b. The lateral portions 222a and 222b extend from the bases 221a of the hollow acoustic elements 221 in direction of the apexes 221b of the hollow acoustic elements 221. In particular, the first lateral portion 222a extends from the base 221a of the first hollow acoustic element 221 connected by the bridge 222, and the second lateral portion 222b extends from the base 221a of the second hollow acoustic element 221 connected by the bridge 222. The bottom portion 222c extends perpendicularly to the height direction DH. Thus, the bridges 222 according to the second embodiment of the invention have a "U" shape.

[0057] Preferably, the bridges 222 are located between the surface comprising the bases 221a of the hollow acoustic elements 221 and the surface comprising the vertices 221b of the hollow acoustic elements 221. Thus, the bridges 222 project towards the vertices 221b of the hollow acoustic elements 221 and not project away from the vertices 221b of the hollow acoustic elements 221.

[0058] Preferably, the 222 brackets have symmetry with respect to a plane perpendicular to the bottom portion 222c. Thus, the first lateral portion 222a and the second lateral portion 222b have the same length and the same angle with the bottom portion 222c.

[0059] The lateral portions 222a and 222b, the bottom portion 222c, and the folds 123a and 123b thus form a wave. The folds 123a and 123b allow the angle between the first lateral portion 222a and the second lateral portion 222b to be varied. Therefore, the length of the bridge 222 along its extension direction DEI can be adjusted. Consequently, the distance between the two hollow acoustic elements 221 connected by the bridge 222 can be adjusted to facilitate the assembly of the acoustic component 220 with the multicellular body 130.

[0060] When the acoustic component 220 is assembled in the multicellular body 130, the bridges 222 cooperate with the upper notches 133 of the partitions 131. The bottom portion 222c is in contact with the upper notches 133. In particular, the bottom portion 222c is in contact with the bottom of the upper notches 133. The assembly between the acoustic component 220 and the multicellular body 130 is thus improved compared to the first embodiment of the invention.

[0061] The hollow acoustic elements 221 are not in contact with the multicellular body 130. Thus, the bases 221a of the hollow acoustic elements 221 are maintained at a non-zero distance from the partitions 131 of the multicellular body 130. The apexes 221b of the hollow acoustic elements 221 are maintained at a non-zero distance from the partitions 131 of the multicellular body 130. The acoustic component 220 is connected to the multicellular body 130 only by the bridges 222. Consequently, fluid drainage is facilitated.

[0062] Figure 4 illustrates an acoustic component 320 comprising bridges 322 according to a third embodiment of the invention. The acoustic component 320 comprises a plurality of hollow acoustic elements 321, each having a shape that gradually narrows from a base 321a to a top 321b. The hollow acoustic elements 321 extend between the base 321a and the top 321b along a height direction DH.

[0063] Figure 4 illustrates the acoustic component 320 assembled with a multicellular body 330. The multicellular body 330 comprises a plurality of partitions 331 which form a network of ribs, thus delimiting cells 332. The partitions 331 each extend between an upper edge 331a and a lower edge 331b. The upper edges 331a of the partitions 331 define a first assembly face 330a of the multicellular body 330. The lower edges 331b of the partitions 331 define a second assembly face 330b of the multicellular body 330. Thus, the cells 132 extend from the first assembly face 330a to the second assembly face 130b of the multicellular body 330. The cells 332 accommodate the hollow acoustic elements 321. Typically, each cell 332 accommodates a single hollow acoustic element 321.

[0064] In this third embodiment of the invention, the partitions 331 are preferably without upper notches on the upper edges 331a of the partitions 331. However, it does not depart from the scope of the third embodiment if the partitions 331 have upper notches.

[0065] The partitions 331 may have lower notches 334 formed at the lower edges 331b of the partitions 331. These lower notches 334 facilitate the evacuation of fluids.

[0066] Each bridge 322 connects the base 321a of a first hollow acoustic element 321 at the base 321a of a second hollow acoustic element 321. Each bridge 322 connects the base 321a of a first hollow acoustic element 321 to the base 321a of a second hollow acoustic element 321 along a proper extension direction DEI.

[0067] In this third embodiment of the invention, the bridges 322 comprise a first fold 323a, a second fold 323b, and a central fold 323c. The folds 323a, 323b, and 323c extend perpendicularly to the height direction DH. The folds 323a, 323b, and 323c extend perpendicularly to the extension direction DEI of the bridge 322. The bridges 322 are formed by a first lateral portion 322a, a second lateral portion 322b, a first central portion 322c, and a second central portion 322d. The lateral portions 322a and 322b extend from the bases 321a of the hollow acoustic elements 321 towards the apexes 321b of the hollow acoustic elements 321. In particular, the first lateral portion 322a extends from the base 321a of the first hollow acoustic element 321 connected by the bridge 322 and the second lateral portion 322b extends from the base 321a of the second hollow acoustic element 321 connected by the bridge 322.The central portions 322c and 322d extend from the ends of the lateral portions 322a and 322b to the central fold 323c. The first lateral portion 322a is separated from the first central portion 322c by the first fold 323a. The second lateral portion 322b is separated from the second central portion 322d by the second fold 323b. Thus, the bridges 322 according to the third embodiment of the invention have a "W" shape.

[0068] The central fold 323c of the brackets 322 can be level with the bases 321a of the hollow acoustic elements 321. In this configuration, the presence of upper notches on the upper edges 331a of the partitions 331 is not necessary. If the central fold 232c of the brackets 322 is recessed relative to the bases 321a of the hollow acoustic elements 321, the presence of upper notches on the upper edges 331a of the partitions 331 is preferable.

[0069] Preferably, the bridges 322 are present between the surface comprising the bases 321a of the hollow acoustic elements 321 and the surface comprising the vertices 321b of the hollow acoustic elements 321.

[0070] Preferably, the 322 bridges exhibit symmetry with respect to a plane including the central fold 323c.

[0071] The lateral portions 322a and 322b, the central portions 322c and 322d, and the folds 323a, 323b, and 323c thus form a wave. The first fold 323a allows variation of the angle between the first lateral portion 322a and the first central portion 322c; the second fold 323b allows variation of the angle between the second lateral portion 322b and the second central portion 322d; and the central fold 323c allows variation of the angle between the first central portion 322c and the second central portion 322d. Therefore, the length of the bridge 322 along its extension direction DEI can be adjusted. Consequently, the distance between the two hollow acoustic elements 321 connected by the bridge 322 can be adjusted to facilitate the assembly of the acoustic component 320 with the multicellular body 330.

[0072] When the acoustic component 320 is assembled in the multicellular body 330, the bridges 322 cooperate with the partitions 331. The central fold 323c is in contact with the partitions 331. The third embodiment of the invention can eliminate the need for upper notches on the partitions 331. If the partitions 331 have upper notches, the central fold 323c can be in contact with the bottom of the upper notches.

[0073] The hollow acoustic elements 321 are not in contact with the multicellular body 330. Thus, the bases 321a of the hollow acoustic elements 321 are maintained at a non-zero distance from the partitions 331 of the multicellular body 330. The apexes 321b of the hollow acoustic elements 321 are maintained at a non-zero distance from the partitions 331 of the multicellular body 330. The acoustic component 320 is connected to the multicellular body 330 only by the bridges 322. Consequently, fluid drainage is facilitated.

[0074] Other embodiments are of course conceivable within the scope of the present invention. In particular, one does not depart from the scope of the invention If the bridges comprise more than three folds or more than two central portions. For example, it does not depart from the scope of the invention if the bridges each comprise several successive modules from among the "U", "V" or "W" modules. For example, a bridge may comprise, in order according to its direction of extension, a "V" section, a "U" section and a "V" section.

[0075] A single acoustic component may comprise only one type of bridge. Of course, the invention remains within the scope of practice if the acoustic component comprises several types of bridges. For example, a single acoustic panel may comprise both bridges according to the first embodiment and bridges according to the third embodiment.

[0076] To facilitate the assembly of the acoustic component with the multicellular body, different configurations are possible for the positioning of the bridges.

[0077] According to a first variant illustrated in figures 1, 2 and 5, one part 1221 of the bridges 122 extends along a first principal direction Di of the acoustic component 120 and the other part 1222 of the bridges 122 extends along a second principal direction D2 of the acoustic component 120. Thus, the proper extension direction DEI of one part 1221 of the bridges 122 coincides with the first principal direction Di of the acoustic component 120 and the proper extension direction DE2 of the other part 1222 of the bridges 122 coincides with the second principal direction D2 of the acoustic component 120.

[0078] Preferably, the angle between the first principal direction Di and the second principal direction D2 of the acoustic component 120 is 60°. Such a value is particularly advantageous when the cells 132 have a hexagonal cross-section and / or when the bases 121a of the hollow acoustic elements 121 are hexagonal in shape.

[0079] This first variant is a compromise which allows a reduced number of bridges to improve the deformability of the acoustic component, but sufficient to ensure satisfactory cohesion of the acoustic component.

[0080] In the example illustrated in Figures 1, 2, and 5, the hollow acoustic elements 121 are connected to each other hollow acoustic elements 121 by four bridges. In particular, the hollow acoustic elements 121 are connected to each other hollow acoustic elements 121 by two opposing bridges 122 extending along the first principal direction Di and by two opposing bridges 122 extending along the second principal direction D2.

[0081] Of course, we do not deviate from this first variant if the number of bridges is increased. Such an increase in the number of bridges allows for greater cohesion of the acoustic component. For example, the hollow acoustic elements 121 can be connected to other hollow acoustic elements 121 by two or three pairs of opposing bridges 122 extending along the first principal direction Di and by two or three pairs of opposing bridges 122 extending along the second principal direction D2.

[0082] According to a second variant illustrated in figures 6 and 7, all the bridges 422, 522 of the acoustic component 420, 520 extend along a first principal direction Di of the acoustic component 420, 520. Thus, the extension direction DEI of the bridges 422, 522 coincides with the first principal direction Di of the acoustic component 420, 520.

[0083] In this second variant, the acoustic components 420a, 420b, 420c, 520a, 520b, 520c are arranged as a strip of hollow acoustic elements 421, 521 in a line. Thus, the second variant allows for excellent deformability of the acoustic component 420a, 420b, 420c, 520a, 520b, 520c.

[0084] Figure 6 illustrates a plurality of acoustic components 420a, 420b, 420c arranged in a multicellular body 430 such as those described previously, comprising partitions with upper edges 431a. In the example shown in Figure 6, the multicellular body 430 includes upper notches 433 such as those described previously. The acoustic components 420a, 420b, 420c comprise hollow acoustic elements 421 having a shape that gradually narrows between a base 421a and an apex 421b. The hollow acoustic elements 421 are connected to other hollow acoustic elements 421 by a single pair of opposite 422 bridges extending along the first principal direction Di.

[0085] To improve the cohesion of the acoustic components in this second variant, the number of bridges can be increased. For example, Figure 7 illustrates a plurality of acoustic components 520a, 520b, 520c arranged in a multicellular body 530 such as those described previously, comprising partitions with upper edges 531a. In the example shown in Figure 7, the multicellular body 530 includes upper notches 533 such as those described previously. The acoustic components 520a, 520b, 520c comprise hollow acoustic elements 521 having a shape that gradually narrows between a base 521a and an apex 521b. The hollow acoustic elements 521 are connected to other hollow acoustic elements 221 by several pairs of opposing bridges 522 extending along the first principal direction Di.

[0086] In the examples illustrated in Figures 5 to 7, the bridges 122, 422, and 522 are bridges according to the first embodiment of the invention. Of course, the use of other types of bridges, for example bridges according to the second or third embodiment of the invention, does not depart from the scope of the invention.

[0087] In all embodiments and variants of the invention, the heights of the cells of the multicellular body are chosen so as to obtain treatment of the frequencies of interest according to the use which will be made of the acoustic panel.

[0088] In the examples illustrated in Figures 1 to 7, the cells of the multicellular body have a hexagonal cross-section. Of course, it remains within the scope of the invention if the cells of the multicellular body have a square, rectangular, round, or other cross-section.

[0089] The multicellular body can be made of polymer, composite, or metallic material, either by additive manufacturing or conventional methods. The multicellular body can also be made using well-known methods from thermoplastic material by injection molding or stamping. The thermoplastic material can be charged with short fibers or with long fibers. The multicellular body may not be charged.

[0090] In the examples illustrated in Figures 1 to 7, the hollow acoustic elements have a pyramidal shape. However, it does not depart from the scope of the invention if the hollow acoustic elements have, for example, a conical, spiral, or funnel shape. In the examples illustrated in Figures 1 to 7, the hollow acoustic elements exhibit symmetry. However, it does not depart from the scope of the invention if the hollow acoustic elements are asymmetrical.

[0091] In the examples illustrated in Figures 1 to 7, the bases of the hollow acoustic elements have a hexagonal shape. Of course, it remains within the scope of the invention if the bases of the hollow acoustic elements have a different shape, for example, a circular, square, or rectangular shape. In the examples illustrated in Figures 1 to 7, the vertices of the hollow acoustic elements have a hexagonal shape. Of course, it remains within the scope of the invention if the vertices of the hollow acoustic elements have a different shape, for example, a circular, square, or rectangular shape.

[0092] Hollow acoustic elements can have a wall thickness ranging from 0.25 mm to 2 mm. Preferably, hollow acoustic elements 121 have a thickness of less than 1 mm, for example, less than or equal to 0.5 mm, for example, between 0.3 mm and 0.5 mm. Such a reduced thickness allows, in particular, for significant flexibility in the acoustic component, which facilitates its shaping and assembly against an acoustic skin. This thickness also reduces the mass of the acoustic component, and thus the overall mass of the acoustic panel of which it will be a part.

[0093] Preferably, the base of the hollow acoustic elements is contained within a circle with a diameter between 8 mm and 25 mm. For example, the base of the hollow acoustic elements is contained within a circle with a diameter of 20 mm. Preferably, the apex of the hollow acoustic elements is contained within a circle with a diameter between 1 mm and 10 mm. For example, the apex of the hollow acoustic elements is contained within a circle with a diameter of 5 mm.

[0094] Preferably, the height H 120 of the hollow acoustic elements is between 5 mm and 100 mm, and preferably between 5 mm and 50 mm. For example, the height of the hollow acoustic elements is 20 mm. The height of the hollow acoustic elements is less than the height of the cells in the multicellular body.

[0095] The acoustic component(s) can be produced by additive manufacturing, injection molding or stamping.

[0096] The first assembly face of the multicellular body is designed to be in contact with an acoustic skin. The acoustic skin's function is to allow the sound waves to be attenuated to pass through to the cells of the multicellular body. To this end, the acoustic skin comprises, as is well known, a plurality of perforations. Preferably, each cell of the multicellular body associated with a hollow acoustic element of the acoustic component corresponds to a plurality of perforations in the acoustic skin. The perforations can have a diameter between 2 mm and 5 mm. The acoustic skin can have a thickness between 1 mm and 5 mm, for example, 2 mm.

[0097] Acoustic skins can be manufactured using well-known methods such as stamping, automated fiber placement (AFP), or automated tape laying (ATL). Other processes, such as manual laying, can also be used to create acoustic skins.

[0098] The acoustic membrane of the opening can be made of a thermoplastic material, for example, a thermoplastic matrix composite material containing fibers. The fibers can be carbon, glass, or aramid. The acoustic membrane of the opening may also be made without fibers. The thermoplastic matrix can be made, for example, of polyaryletherketone (PAEK), polyetherketoneketone (PEKK), polyetherimide (PEI), polyphenylene sulfide (PPS), polyethersulfone (PESU), or polycarbonate (PC). The acoustic membrane of the opening can also be made of a thermosetting material, for example, a composite material comprising fibers and a thermosetting matrix.

[0099] The second assembly face of the multicellular body is intended to be in contact with a closure skin or wall. The closure skin can be produced using well-known methods such as stamping, automated fiber placement (AFP), or automated tape laying (ATL). Other processes can also be used to manufacture the closure skin. For example, the closure skin can be pre-cured and then bonded to the multicellular body. If the closure skin is made of a thermosetting material, it can be formed and cured directly onto the multicellular body.

[0100] The closing skin can be made of thermoplastic or thermosetting material. It can be made of a composite material containing fibers, for example, a composite material based on carbon fibers impregnated with a thermoplastic or thermosetting resin. Alternatively, the closing skin may not contain fibers. It can also be made of a thermoplastic material, for example, a thermoplastic matrix composite material containing fibers. The fibers can be carbon, glass, or aramid. The thermoplastic matrix can be made, for example, of polyaryletherketone (PAEK), polyetherketoneketone (PEKK), polyetherimide (PEI), polyphenylene sulfide (PPS), polyethersulfone (PESU), or polycarbonate (PC).

[0101] The acoustic skin can be assembled to the multicellular body by bonding, welding, or a combination of both. The acoustic component(s) can be assembled to the multicellular body by bonding, welding, or a combination of both.

[0102] The closure skin can be assembled to the multicellular body by gluing, by welding, or simultaneously by gluing and welding.

[0103] This results in an acoustic panel comprising the acoustic skin, the acoustic component(s), the multicellular body and possibly the closing skin.

[0104] Acoustic panels can be used, for example, for sound attenuation in an aircraft nacelle or engine, for a turbine platform, or for an aircraft sleeve. Acoustic panels can also be used for sound attenuation in a ventilation and / or air conditioning system.

[0105] The expression "between ... and ..." should be understood as including the boundaries.

Claims

Demands

1. Acoustic component (120) comprising a plurality of hollow acoustic elements (121) having a shape that gradually narrows between a base (121a) and a top (121b), the bases (121a) of the hollow acoustic elements (121) being connected to each other by bridges (122), the acoustic component (120) being characterized in that the bridges (122) have at least one undulation.

2. Acoustic component (120) according to claim 1, wherein each bridge (122) extends between two bases (121a) along an extension direction (DEI), the undulation being formed by at least one fold (123, 223a, 223b, 323a, 323b, 323c) extending perpendicularly to the extension direction (DEI) of the bridge (122).

3. Acoustic component (120) according to claim 1 or 2, wherein at least a portion of the bridges (122) comprises a single fold (123) separating two lateral bridge portions (122a, 122b), the lateral bridge portions (122a, 122b) extending from the bases (121a) to the tops (121b) of the hollow acoustic elements (121).

4. Acoustic component (220) according to any one of claims 1 to 3, wherein at least a portion of the bridges (222) comprises exactly two folds (223a, 223b), the first fold (223a) separating a first lateral portion of the bridge (222a) from a bottom portion of the bridge (222c) and the second fold (223b) separating a second lateral portion of the bridge (222b) from the bottom portion (222c), the lateral portions of the bridge (222a, 222b) extending from the bases (221a) to the tops (221b) of the hollow acoustic elements (221).

5. Acoustic component (320) according to any one of claims 1 to 4, wherein at least a portion of the bridges (322) comprises exactly three folds (323a, 323b, 323c), the first fold (323a) separating a first lateral portion of the bridge (322a) from a first central portion of the bridge (322c), the second fold (323b) separating a second lateral portion of the bridge (322b) of a second central portion of the bridge (322d) and the third fold (323c) separating the first central portion of the bridge (322c) from the second central portion of the bridge (322d), the lateral portions of the bridge (322a, 322b) extending from the bases (321a) to the tops (321b) of the hollow acoustic elements (321) and the central portions of the bridge (322c, 322d) extending from the first and second folds (323a, 323b) to the bases (321a) of the hollow acoustic elements (321).

6. Acoustic component (420; 520) according to any one of claims 1 to 5, wherein all the bridges (422; 522) extend along the same principal direction (Di) of the acoustic component (420; 520).

7. Acoustic component (120) according to any one of claims 1 to 5, wherein one part (1221) of the bridges (122) extends along the same first principal direction (Di) of the acoustic component (120) and the other part (1222) of the bridges (122) extends along a second principal direction (D2) of the acoustic component (120) intersecting the first principal direction (Di).

8. Acoustic component (120; 420) according to any one of claims 1 to 7, wherein two adjacent bases (121a; 421a) are connected at most by a bridge (122; 422).

9. Acoustic component (520) according to any one of claims 1 to 7, wherein two adjacent connected bases (521a) are connected by a plurality of bridges (522) extending along the same principal direction (Di).

10. Acoustic panel comprising at least one acoustic component (120) according to any one of claims 1 to 9 and a multicellular body (130) comprising a plurality of partitions (131) delimiting cells (132), the hollow acoustic elements (121) of the acoustic component (120) being arranged in the cells (132) of the multicellular body (130) such that the bridges (122) are in contact with the partitions (131) of the multicellular body (130) and that the bases (121a) of the hollow acoustic elements (121) are spaced from the partitions (131) of the multicellular body (130).

11. Acoustic panel according to claim 9 related to claim 3, wherein the single fold (123) of the bridges (122) is in contact with the partitions (131) of the multicellular body (130).

12. Acoustic panel according to claim 9 related to claim 4, wherein the bottom portion (222c) of the bridges (222) is in contact with the partitions (131) of the multicellular body (130).

13. Acoustic panel according to claim 9 related to claim 5, wherein the third fold (323c) of the bridges (322) is in contact with the partitions (331) of the multicellular body (330).

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