Abstract: A sandwich panel for an aircraft turbojet nacelle includes an outer skin in contact with an air flow, an inner skin opposed to the outer skin, and an intermediate system comprising partitions connecting the inner and outer skins so as to form cells, the inner skin of at least one cell having at least one corrugation configured to allow the materials making up the sandwich panel to deform in the event of thermal variation.

Abstract: An acoustic panel with a cellular core includes cells that are provided with one or more obstacles, each of the obstacles extending transversely in relation to the main axis of the associated cell so as to increase the length of the path (F) that sound waves travel through the cell. Methods enabling the production of such a panel implements steps of cutting, folding and bonding that are suitable for creating cells provided with such obstacles.

Abstract: An rear fairing for a pylon supporting an aircraft turbojet engine forms an aerodynamic surface covering the base of the pylon. The rear fairing is elongated in a longitudinal direction and includes a floor arranged opposite the hot gases exiting the turbojet engine and side walls constituting aerodynamic surfaces. The floor and the side walls include ceramic matrix composite materials made from preforms formed by layers of superimposed warp and weft yarns, the preforms have interlayer weaving yarns connecting the layers to one another.

Abstract: A structure for the nacelle of an aircraft propulsion unit includes a first skin and stiffeners arranged to hold acoustic treatment modules against the first skin. Each acoustic treatment module includes a honeycomb core and a second skin, such that the honeycomb core is sandwiched between the first skin and the second skin. Such a structure allows the structural reinforcement function provided by the stiffeners to be separated from the acoustic treatment function performed by the acoustic treatment modules which are simply bearing on the first skin.

Abstract: A thrust reverser cascade for an aircraft nacelle includes a plurality of blades having a first and a second surface, the blades being connected to members connected to attachment flanges for attaching the thrust reverser cascade to the nacelle. At least one of the surfaces of the blades is covered with at least one layer of fibers, each layer including a plurality of fiber pieces which are pre-impregnated with resin. The fiber pieces are superimposed on one another, positioned parallel to the aerodynamic surface of the blade and oriented in different directions.

Abstract: A method of manufacturing a preform including a core and a sole includes contour weaving the preform on a lap roller having a groove or an outgrowth allowing shape weaving of the core and the sole of the preform. At least one portion of the core and at least one portion of the sole include weft yarns which cross each other on common warp yarns.

Abstract: A method for manufacturing a fibrous tubular structure including lobes, in which fibers are draped/deposited on a mandrel having a shape corresponding to that of the fibrous structure, includes draping/deposition carried out such that at least one group of fibers has a same orientation with respect to the axis (A) of said fibrous structure, then, the fibers having been draped over an angular sector less than the total periphery of the mandrel, one of the ends of the fibrous structure is separated from the mandrel in order to allow the continuation of the draping on the same mandrel.

Abstract: Tooling for manufacture of an apertured element made of a composite material includes first and second sole plates and tooling elements. Each sole plate is configured to be placed on either side of the apertured element to be manufactured. The tooling elements are placed between the first and second sole plates. The tooling elements include at least one core and peripheral bars. The core is configured to delimit a cell of the apertured element to be manufactured. The core is movable in translation along the first and second sole plates. The peripheral bars are placed on a periphery of the core and configured to delimit the apertured element to be manufactured. At least one peripheral bar is movable in translation along the first and second sole plates.

Abstract: The present disclosure relates to a cell structure for an acoustic attenuation device for a nacelle of an aircraft propulsion assembly. This cell structure includes lateral partitions forming channels that each extend between a first end and a second end and skin elements arranged so that each channel is at least partly closed at the first end thereof by at least one skin element. Each skin element is connected to a respective lateral partition and can move relative to the other lateral partitions. A continuous skin can be assembled on this cell structure so as to at least partly close the channels at the second end thereof and to thus form an acoustic attenuation device.

Abstract: An acoustic attenuation panel includes a cellular structure including a plurality of acoustic cells separated from one another by peripheral partitions, a perforated acoustic structure, the perforated acoustic structure and the cellular structure being formed in one piece in a first material, and a porous acoustic layer formed of a second material and fastened to a surface of the perforated acoustic structure by entangling the first material and the second material.

Abstract: An acoustic attenuation panel includes a perforated acoustic wall, a first honeycomb structure coupled to the perforated acoustic wall and including a plurality of acoustic cells defined by peripheral partitions, a second honeycomb structure including a plurality of acoustic cells defined by peripheral partitions, and a septum which includes a plurality of macro-perforations and is positioned between the first honeycomb structure and the second honeycomb structure. Each acoustic cell of the first honeycomb structure and each acoustic cell of the at least second honeycomb structure are arranged opposite a single perforation of the septum.

Abstract: An air intake of a turbojet engine nacelle includes an annular structure including an outer fairing defining an aerodynamic outer surface and an inner fairing defining an aerodynamic inner surface. The outer and inner fairings are connected upstream by an air intake lip forming a leading edge. The inner fairing includes an outer skin fixed to the air intake lip by an upstream fixation flange, and the outer skin is configured to be fixed to an outer fan casing by a downstream fixation flange. The air intake includes at least one independent acoustic panel attached to the outer skin and which includes a perforated acoustic skin and a cellular core.

Abstract: A tubular structure having lobes is produced as a single piece over at least two lobes. Circumferential fibres of the structure have a constant orientation with respect to the longitudinal axis (A) of the structure in any plane (P) transverse to the longitudinal axis. The structure is obtained by weaving or by filament winding.

Abstract: A method for manufacturing a sound attenuating panel uses an alveolar-core structure including a first edge and a second edge separated by alveolar cells, the alveolar cells including walls extending from the first and second edges and defining a primary conduit for the circulation of a sound wave that is to be attenuated. The method includes covering the first edge or the second edge of the alveolar-core structure with a compartmentation wall; deforming the compartmentation wall to define at least one secondary conduit for the circulation of a sound wave that is to be attenuated, the secondary conduit extending at least partially within said primary conduit; and creating an opening in the compartmentation wall to permit communication between the primary and secondary conduits.

Abstract: A sandwich panel for an aircraft turbojet nacelle includes an outer skin in contact with an air flow, an inner skin opposed to the outer skin, and an intermediate system comprising partitions connecting the inner and outer skins so as to form cells, the inner skin of at least one cell having at least one corrugation configured to allow the materials making up the sandwich panel to deform in the event of thermal variation.

Abstract: A part for an aircraft turbojet engine nacelle is made of a composite material and includes at least one outer face (S1), a fibrous preform including fiber locks and having a surface(s) delimiting depressions between fiber locks, a covering material which at least partially covers the surface(s) of the fibrous preform and in particular the depressions, and a matrix which binds entirely the covering material and the fibrous preform. The covering material is a fibrous mat and the outer face (S1) is smooth. A method for manufacturing such a part includes manufacturing the fibrous preform, providing a fibrous mat, depositing the fibrous preform and fibrous mat in a mold, dispersing the matrix between the fibers of the preform and mat and consolidating the fibrous preform and mat.

Abstract: A process for manufacturing a composite part includes arranging a fibrous preform in a mold including an impregnation chamber which includes in its lower part a filter by making a first face of the preform rest on the filter, the impregnation chamber being closed by a flexible membrane placed opposite a second face of the preform, the membrane separating the impregnation chamber from a compaction chamber. The process further includes injecting a compression fluid into the compaction chamber so as to apply a first pressure on the membrane and injecting a slurry including ceramic particles into the impregnation chamber with a second pressure while maintaining the injection of the compression fluid, the second injection pressure of the slurry being lower than the first pressure on the membrane.

Abstract: A method of fabricating a composite part, includes forming a fiber preform for the part that is to be obtained by depositing a plurality of fiber structures impregnated with a thermoplastic polymer onto a surface, with deposition being performed by automated fiber placement; eliminating the thermoplastic polymer present in the preform by dissolution with a solvent; and injecting a liquid impregnation composition into the pores of the fiber preform after eliminating the thermoplastic polymer in order to form a matrix in the pores of the fiber preform.

Abstract: An installation for depositing a shaped filled roving intended to be used to manufacture a composite-material component, includes a device for feeding a fibrous roving impregnated with a composition including a binder and ceramic or carbon fillers, a die for shaping and draining the binder defined by at least one porous surface, the die having an evolving section between an inlet section and an outlet section, the inlet section being larger than the outlet section, a support in communication with the die outlet on which the shaped roving is to be deposited, and a first conveying device configured to convey the roving from the feed device through the die and to the support.

Abstract: A method for producing an acoustic attenuation panel from a composite material with a ceramic oxide matrix is provided that includes draping a plurality of plies having fibrous reinforcements including fibers of ceramic material in a mold to define a first skin, depositing blocks made of fugitive material on the first skin such that a space between two blocks is defined, and draping a second plurality of plies on a surface formed by the blocks such that a second skin is defined. Rounded corners of the blocks define radii for connecting the first and second skins with walls of a honeycomb core of the acoustic panel. The method further includes using a liquid medium to infiltrate the skins and spaces with a precursor of a ceramic phase, removing the liquid medium by evaporation or polymerization, and sintering to consolidate the ceramic oxide material and removal the fugitive material.