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 for manufacturing a preform has a non-developable end shape having, about a longitudinal axis (A), an end overall radius of curvature (R2), and, in at least a longitudinal section, curved segments forming bending radii linking straight segments. The method includes a step of depositing successive layers giving the preform an initial substantially rotational shape having, about the longitudinal axis (A), an initial overall radius of curvature, then a step of deploying the preform by increasing the initial overall radius of curvature until the end overall radius of curvature is reached (R2), in order to close the bending radii of the curved segments.

Abstract: The present disclosure concerns a porous body made of a ceramic-matrix composite material for an acoustic attenuation panel and a method of manufacturing the porous body. The porous body includes a plurality of interwoven ceramic fibers, a metal oxide matrix, and a plurality of channels interwoven with the ceramic fibers and interconnected together. The channels define at least one cavity. In one form, at least one channel is wrapped around a ceramic fiber. In another form, at least one ceramic fiber and at least one channel are twisted together. In yet another form, at least one channel is wrapped around a ceramic fiber and twisted with the ceramic fiber. The present disclosure also concerns an acoustic attenuation panel including the porous body and an aircraft propulsion unit having such a panel.

Abstract: The present disclosure particularly relates to an acoustic attenuation structure for a propulsion assembly of an aircraft. The acoustic attenuation structure includes an acoustically reflective wall and a sandwich panel. The sandwich panel includes a honeycomb structure surrounded by two acoustically porous skins, a rear skin and a skin. The acoustically reflective wall and the sandwich panel are arranged in such a way as to be separated by a layer of air.

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: 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 panel for a nacelle of an aircraft propulsion assembly includes two skins and a cell structure provided with transverse partitions defining cells. The cell structure includes folds with at least one central part forming at least one part of at least one transverse partition and at least one peripheral part extending along at least one of the skins. A nacelle with such a panel is provided, as well as a method for manufacturing such a panel.

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: The present disclosure concerns a preform for a curved composite stiffener for an axisymmetric part such as a shroud, including at least one web and at least one flange curved about an axis of revolution of the preform and defining a substantially “T” or an “I” shaped section. In one form, the preform includes a web and a flange, wherein the web includes a plurality of warp yarns circumferentially oriented relative to the axis of revolution of the preform, and a plurality of weft yarns oriented radially relative to said axis, and the flange includes a plurality of warp yarns circumferentially oriented relative to the axis of revolution of the preform, and a plurality of weft yarns substantially parallel to said axis.

Abstract: The present disclosure provides a method for manufacturing a preform made of reinforcement fibers woven in a longitudinal direction. The preform is impregnated with resin in order to form an elongated element having a variable transverse cross-section. In one form, the method includes the step of simultaneously including a reduction (or increase) in width and an increase (or reduction) in height. The variable cross-section includes, along the length thereof, a consistent number (c) of continuous warp threads arranged in layers. The method for reducing width includes carrying out a change in weave, adding additional weft threads, and simultaneously drawing the teeth of the longitudinal beater reed closer together so as to increase the number of layers.

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: 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: 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: A method for manufacturing a preform has a non-developable end shape having, about a longitudinal axis (A), an end overall radius of curvature (R2), and, in at least a longitudinal section, curved segments forming bending radii linking straight segments. The method includes a step of depositing successive layers giving the preform an initial substantially rotational shape having, about the longitudinal axis (A), an initial overall radius of curvature, then a step of deploying the preform by increasing the initial overall radius of curvature until the end overall radius of curvature is reached (R2), in order to close the bending radii of the curved segments.

Abstract: The disclosure relates to a shape-woven preform which has an omega-shaped cross-section including a core and a sole. At least one part of the core and at least one part of the sole have weft yarns in common with one another.

Abstract: A method for manufacturing a preform has a non-developable end shape having, about a longitudinal axis (A), an end overall radius of curvature (R2), and, in at least a longitudinal section, curved segments forming bending radii linking straight segments. The method includes a step of depositing successive layers giving the preform an initial substantially rotational shape having, about the longitudinal axis (A), an initial overall radius of curvature, then a step of deploying the preform by increasing the initial overall radius of curvature until the end overall radius of curvature is reached (R2), in order to close the bending radii of the curved segments.

Abstract: A material of pre-impregnated woven fibers for a part is in the form of a fibrous mat having at least one layer of several pieces of fibrous fabric pre-impregnated with resin. At least one portion of the fabric has a low-shrinkage contexture. The pieces of fabric are positioned parallel with the plane (X, Y) of the fibrous mat and orientated in different directions in the plane (X, Y).

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 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: 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.