Abstract: A method for manufacturing a soundproofing assembly involving providing a first panel of honeycomb structure, fastening an intermediate plate against a second face of the first panel, adhesive-coating a layer of adhesive on the intermediate plate, providing a second panel of honeycomb structure, bonding the first face of the second panel to the layer of adhesive, and perforating the intermediate plate and the layer of adhesive through the cells of the first panel or the cells of the second panel at the bonding zone of the second panel. Such a method makes it possible to save time by dispensing with additional preparation steps.

Abstract: An acoustic panel comprising a cellular structure, such as a honeycomb structure, having cells that open at least onto a first frontal face of the structure. The panel comprises a capsular skin which is fastened to the first frontal face of the cellular structure next to a plurality of cells. The capsular skin including a continuous layer of material, in one piece, forming capsules that extend into the cellular structure. At least one channel is provided at the apex of each capsule for the passage of acoustic waves. Such a panel effectively attenuates the noise of aircraft engines, in particular, the low frequencies. It is extremely easy to manufacture industrially, the capsular skin being able to be obtained by molding with polymerization in situ, the polymerizable material then adhering to the cellular structure while it polymerizes.

Abstract: An acoustic panel (1) includes a plate (2) made of an acoustic absorbing material (3), as well as a resistive skin (4) and a backing skin (6) arranged respectively on both sides of the plate (2), the acoustic panel (1) including acoustic elements (8) able to carry out an acoustic absorption, each of them being arranged in a housing (7) provided in the plate (2) with an opening (9) in front of the resistive skin (4). The combination of the plate (2) and the acoustic elements (8) allows to combine the sound attenuation properties of these two types of elements and to increase the frequency range of sounds that can be attenuated by the acoustic panel (1), without increasing the dimension.

Abstract: A cellular sound insulation structure and associated aircraft, a cell of which is provided with a diaphragm which includes a membrane having at least one orifice passing through a thickness of the membrane, and at least one tube surmounting the orifice and extending from a face of the membrane into one compartment of the cell, the tube comprising a free end, forming an acoustic outlet, which is positioned at a distance (p) from the base cross section of the cell. Also, a method for manufacturing such a cellular sound insulation structure, as well as to a tool for inserting a diaphragm into a cell. Such a cellular structure makes it possible to treat a wider acoustic frequency spectrum, and its acoustic dimensioning as well as its manufacture are simplified.

Abstract: A method for producing an alveolar soundproofing structure in which a portion of a membrane of a diaphragm including an acoustic outlet is inserted into a hole of a perforated membrane which covers a cell of the alveolar structure, and the diaphragm is pressed into the cell with the perforated membrane becoming deformed and is fixed at that location. It also relates to the alveolar structure. Such a method enables different types of diaphragms to be inserted into different configurations of cells and enables the diaphragm to be fixed therein, in accordance with the sound frequencies to be processed.

Abstract: A method for manufacturing an acoustic absorption structure including an acoustically resistive layer, a cellular structure, a reflective layer and a plurality of acoustic elements positioned in cavities produced in the cellular structure. This method comprises steps of depositing fiber plies on a contact surface of the cellular structure, fitting a flexible jacket which covers a stack composed of the acoustically resistive layer, the cellular structure and the fiber plies, which is tightly linked with the deposition surface all around the stack, consolidating the fiber plies to form the reflective layer and the fixing thereof on the cellular structure, with a caul plate being inserted between the fiber plies and the flexible jacket during the consolidation step.

Abstract: An assembly constituting an acoustically absorbent material and including a first panel, a second panel pierced with holes, an intermediate panel pierced with through-holes and arranged between the first panel and the second panel, a first structure between the first panel and the intermediate panel and including first cages, a second structure between the second panel and the intermediate panel and including second cages, and for each through-hole of the intermediate panel, a tube opening out at the two ends thereof, where one of the ends of the tube is fixed to the intermediate panel at the through-hole, and where the other end of the tube is accommodated inside a first cage. Such an assembly makes it possible to obtain broad-band attenuation and is easy to manufacture.

Abstract: A method for manufacturing a porous layer of an acoustic attenuation structure, porous layer of an acoustic attenuation structure thus obtained and acoustic attenuation structure comprising the porous layer. A method for manufacturing a porous layer of an acoustic attenuation structure includes a first step of production of a solid layer including at least one structural frame embedded in a resin matrix and having first and second reinforcing strips arranged so as to delimit zones without reinforcing strips and a second step of production of through-holes in the zones without reinforcing strips of the solid layer using a laser beam.

Abstract: A method for producing an acoustically resistive structure includes the steps of creating, consolidating and cutting a first layer of reinforcing fibres embedded in a first thermoplastic resin having a first melting point so as to obtain an interlayer, a step of laying a second layer of reinforcing fibres against a first face of the interlayer, a second consolidation step of consolidating the second layer of reinforcing fibres embedded in a second thermoplastic resin having a second consolidation temperature lower than the first melting point of the first resin so as to obtain a non-perforated external layer bound to the interlayer, a step of perforating the external layer and a step of laying an internal layer on a second face of the interlayer. An acoustically resistive structure obtained from the method as well as a sound-absorption panel including such an acoustically resistive structure are also described.

Abstract: A method for manufacturing a sound absorption structure comprising a cellular panel, a porous layer positioned on a cellular panel first face, a reflective layer positioned on a cellular panel second face and a plurality of acoustic elements positioned in the cellular panel. The method comprises the steps of producing, for each acoustic element, a recess in the cellular panel opening out onto the first and second faces of the cellular panel, inserting the acoustic elements into their recesses, laying an anchoring layer on the second cellular panel face, curing or polymerization at a first pressure to connect each acoustic element to the cellular panel and/or to the anchoring layer, putting in place the porous layer and the reflective layer, and curing or polymerization at a second pressure to connect the porous layer and the reflective layer to the cellular panel.

Abstract: An acoustic absorption structure comprising a plurality of resonators. Each resonator comprises a first chamber which has a first mouthpiece delimited by an edge pressed against an inner surface of a porous zone of a skin so that the first chamber and the skin delimit a first cavity, a second chamber, in which is positioned the first chamber, which delimits, with the first chamber, a second cavity, at least one acoustic orifice passing through the first chamber, at least one drainage orifice passing through the first chamber and at least one drainage hole passing the second chamber, each drainage orifice and each drainage hole being configured to limit an accumulation of fluid in the resonator. Also, an aircraft propulsive assembly or an aircraft comprising the acoustic absorption structure are provided.

Abstract: An assembly forming an acoustic insulator having a first sheet, a pierced second sheet, and a plurality of first and second structures. Each first structure comprises a first and a second strip, wherein each is shaped to form half of the wall of a cage and wherein, for two successive halves, each strip comprises a facet of a joining wall. Each second structure is made up of a first and a second strip, wherein each is shaped to form half of the wall of a cone, wherein. For each strip, at least one of the wall halves of each cone is pierced. For two successive halves, each strip comprises one facet of the connecting wall. Each cone is located in a cell and each connecting wall is located between the two facets of a joining wall, and, between two adjacent first structures, a second structure is likewise fitted.

Abstract: A process for manufacturing an acoustic panel including at least one acoustically resistive layer, at least one cellular structure and a reflective wall. The process includes steps of depositing the parts of the acoustic panel made of thermosetting composite, depositing a film made of thermoplastic resin that is miscible with the thermosetting composite at the polymerization temperature of the thermosetting composite, polymerizing the parts of the acoustic panel made of thermosetting composite, and depositing and consolidating at least one layer made of thermoplastic composite against the film made of thermoplastic resin in order to form the reflective wall.

Abstract: An acoustic panel for an aircraft nacelle includes a cellular layer configured to trap noise, a backplate fixed to one surface of the cellular layer and a facesheet fixed to another, opposite, surface of the cellular layer. The facesheet includes a layer of a preimpregnated woven material containing weft yarns spaced apart from one another and warp yarns spaced apart from one another so that the facesheet exhibits openings between the yarns.

Abstract: An acoustic panel (1) includes a plate (2) made of an acoustic absorbing material (3), as well as a resistive skin (4) and a backing skin (6) arranged respectively on both sides of the plate (2), the acoustic panel (1) including acoustic elements (8) able to carry out an acoustic absorption, each of them being arranged in a housing (7) provided in the plate (2) with an opening (9) in front of the resistive skin (4). The combination of the plate (2) and the acoustic elements (8) allows to combine the sound attenuation properties of these two types of elements and to increase the frequency range of sounds that can be attenuated by the acoustic panel (1), without increasing the dimension.

Abstract: A method for obtaining a porous acoustic layer, comprising a step of deposition of a plurality of fiber wicks arranged in at least two secant directions, the width, the orientation and/or the spacing of the fiber wicks being determined as a function of the open surface ratio desired for each zone of the porous acoustic layer. A porous acoustic layer obtained according to the method, as well as an acoustic panel comprising at least one porous layer, are also disclosed.

Abstract: A structure made of composite material for a propulsive aircraft assembly includes at least one thermal zone designed to receive electrical energy. Each thermal zone includes at least one resistive skin having an inner film produced in a thermoplastic material made conductive by the inclusion of carbon nanotubes, such that each resistive skin is designed to dissipate, by Joule effect, at least a portion of the electrical energy received by the thermal zone, an intermediate ply produced in a satin fabric impregnated with a thermoplastic material, and an outer film produced in a thermoplastic material.

Abstract: A process for manufacturing an acoustic panel including at least one acoustically resistive layer, at least one cellular structure and a reflective wall. The process includes steps of depositing the parts of the acoustic panel made of thermosetting composite, depositing a film made of thermoplastic resin that is miscible with the thermosetting composite at the polymerization temperature of the thermosetting composite, polymerizing the parts of the acoustic panel made of thermosetting composite, and depositing and consolidating at least one layer made of thermoplastic composite against the film made of thermoplastic resin in order to form the reflective wall.

Abstract: An acoustic panel for an aircraft nacelle includes a cellular layer configured to trap noise, a backplate fixed to one surface of the cellular layer and a facesheet fixed to another, opposite, surface of the cellular layer. The facesheet includes a layer of a preimpregnated woven material containing weft yarns spaced apart from one another and warp yarns spaced apart from one another so that the facesheet exhibits openings between the yarns.