FR3002548A1 - METHOD FOR WEAVING A RELIEF FABRIC, WEAVING FABRIC FOR CARRYING OUT THE METHOD, AND PREFORM USING SUCH A RELIEF TISSUE - Google Patents

Abstract

The invention relates to a loom for carrying out the method of the invention and to a preform for a composite part using such a niche fabric. The method of weaving a fabric in relief in the warp direction consists in locally making a relief like a niche ( 2, 3) in the warp direction by overconsumption of weft threads by lifting warp threads at least on one side of a baseline (5; 81). Application to the production of aeronautical parts, such as nacelle elements of aircraft turbojets.

Description

The present invention relates to a method of weaving a raised fabric. It also relates to a loom for carrying out the method of the invention and a preform for composite part using such a fabric in relief. This process and this preform can be used in particular for the manufacture of fabrics for the preparation of composite materials, obtained by polymerization of resins around these fabrics. In particular, the raised fabric is a niche fabric. Such composite materials may be used in particular for the manufacture of aeronautical parts, such as nacelle elements of aircraft turbojet engines. In the state of the art, it is already known to produce niche fabrics in the direction of the weft. However, especially in the case of the two-slot fabric, it is then possible to manufacture preforms for producing rails or other elongated elements. The weaving of crenellations in the weft direction 15 has the disadvantage in particular of limiting the length of the rail made of composite material based on such a preform to the width of the loom while the length in the direction of the warp is not a priori limited. The production of elongated parts is known based on metal structures. However, particularly in the field of aviation, such parts 20 have a mass that it is now necessary to reduce and more exhibit fatigue embrittlement phenomena during their lifetime. The use of composite parts made on the basis of fabric preforms has therefore been initiated. As described above, these preforms are currently woven into the width of the loom, which reduces the possible length of parts produced. Pultrusion techniques have also been used. Pultrusion makes it possible to obtain the continuity of the wires. But the wires must remain oriented along the longitudinal axis with a low tolerance on the angle to this axis. The technique of draping and assembling preforms injected by RTM (Resin Transfer Molding) method has also been used. The directions of the son are then little constraints, but the son are not continuous in all or part of the final piece. In addition, the assembly involves stitching or sewing operations, which are additional operations to weaving. The whole becomes a complex industrial process.

The present invention provides a remedy for these disadvantages of the state of the art. Indeed, the present invention relates to a method of weaving a raised fabric. The method consists in locally producing a relief such as a slot by overconsumption of weft yarns by lifting warp yarns at least on one side of a given baseline. According to other optional features of the present invention: the method also consists of carrying out bonding and / or stripping of warp son layers to delimit at least one slot in the warp direction on said determined baseline; the method consists in providing insertion of weft threads at determined heights and lifting of at least one web of at least one warp thread determined according to the desired architecture of the fabric; the method comprises performing a packing of the weft son after said determined lifting step; the method consists in organizing at least one crowd by sequencing warp yarns on at least one web of at least one warp according to the lifting associated with a sheet of warp yarns. It also relates to a loom for implementing the method according to one of the preceding claims, of the kind comprising at least one weft packing comb and a chain son sequencing system. The loom has at least one lifting comb located in relation to the tamping comb between said tamping comb and the sequencing system so that at least one web of at least one warp is raised by at least one side of a baseline and so it causes over-consumption of weft son on a frame insertion system at heights determined by the desired architecture of the fabric. According to other optional characteristics of the loom according to the invention: the lifting comb comprises a plurality of hooks movable according to a determined law of lifting of at least one warp belonging to a web of warp son selected in function in the architecture of the fabric, the movable hooks are associated in at least one movable module integral with the tamping comb so that the lifting movement is carried out perpendicularly to the tamping movement - the sequencing system of the warp threads comprises a plurality of smooth of at least two types, each type of bar being assigned to control the crowd of a determined web of warp son according to the desired architecture of the fabric, at least some of the smooth of at least one type being controlled to produce binding and / or stripping of strings of warp threads in a defined area of the fabric architecture. It also relates to a chain-shaped netting fabric preform obtained by the method in which the slots are arranged in relief on at least one side of a baseline in the raster plane. According to other optional features of this preform: the preform is used directly or integrated to produce composite material parts comprising profiles, beams, rails, slides, stiffeners, composite panels; The preform is attached to another preform by gluing or stitching to produce a stiffener, or a composite panel; the weaving yarns are chosen from technical weaving materials including Kevlar, glass, polyester, cotton and carbon fiber. Other advantages and features of the present invention will be better understood from the description and the appended figures, in which: FIG. 1 represents in a profile view in the right-to-left frame direction, a preform of composite piece based on a niche fabric made according to the weaving method of the invention; Figure 2 is a diagram explaining an operation of the weaving process of the invention; Figure 3 shows a novel component used in a loom according to the invention, in an illustrative example; Figure 4 shows a mode of operation of the component 30 of Figure 3; Figure 5 shows another state in an operating mode of the component of Figure 3; Figure 6 shows a block diagram of a loom in one embodiment of the invention; Figure 7 shows an operating diagram of the component of Figure 3 in one embodiment of the method of the invention; and Figure 8 shows another preform obtained on a loom of the invention according to the weaving method of the invention. Figure 1 shows a preform 1 for composite part made of a netting fabric in the weft direction, produced according to the method of the invention. In the following, we call: - Crenellum, a zone of raised fabric, at least a part of which is connected to the remainder of the crenellated tissue and of which another part is loosened from the rest of the tissue so as to form a cavity or pocket in relief on the fabric, the untied portion of the fabric zone creating the crenel being of a different length from the rest of the fabric from which it is loosened to allow the relief; 15 - Baseline, in a weft plane, a fictional line on at least one side of which a crenel is raised; and - Architecture, the definition of the various areas of fabric composing the baseline and the raised parts of the fabric as a niche tissue. The drawing of FIG. 1 corresponds to a frame plane, the weft thread occupying one or more levels in this plane. Starting from the flat edge of the preform to the right 7, the weft thread passes over the top of the preform 1 to take the form of a first slot on the right, or pocket 3. Coming down from the top of the slot 3, the weft thread enters a flat interzone 6 then goes up by a slope 10, a flat 9, a downward slope 8 25 to descend on a flat left edge 4. At least two weft son are used, one to weave the layers in relief slots 2 and 3, the other for weaving the baseline 5 of the preform between the edges 4 and 7. Then advancing a weft pitch for weaving the next weft, the weaving method of the invention thus progresses in successive planes, parallel along the warp son, which are substantially aligned with the normal to the plane of the drawing. As a result, the slots 2, 3 are elongated in the warp direction, which makes it possible to obtain large lengths of slots. Of course, the weft yarns described herein are interwoven with at least one layer of warp yarns, not shown, directed normal to the plane of the drawing.

Of course, in a real product, several layers of weft yarns are added in additional layers of weft yarns to the single weft layer described in FIG. 1 and their weaving with one or more layers of warp yarns is carried out according to any desired armor.

The two slots left 2 and right 3 of Figure 1 were made of the same size in the frame plane. Of course, their sizes may be different. Likewise, the section in the raster plane may evolve differently or identically along the crenel generators along the warp yarns. One of the slots may be interrupted and its weft threads and warp yarns join the top of the plane extending beyond the baseline 5 in Figure 1. In addition, the number of slots counted in the frame direction is not limited. In particular, it should be noted that, preferably, the flat interzones, such as the flat zone 6 and the edges 4 and 7 of the preform, are made by bonding the layers of warp threads that occupy these zones. The loosening is operated only at the opening of the frame to achieve one or the other of the two slots. Only one slot can be created, or more than two slots. Similarly, it has been described a disposition of the slots on the same side, here higher, of a baseline of the preform. The weaving method and the loom of the invention make it possible to produce reliefs such as crenellations on either side of a baseline (in a weft plane) characterizing the niche tissue so to produce a raised fabric on one side or the other of this baseline.

In an embodiment that will be described below, several slots are made in each other by reserving weft son for each of them in a multilayer treatment. In one embodiment, the height of the slot as the slot 2 varies according to the frame sections along the chain. The method of the invention largely allows the realization of three-dimensional tissue architectures. To this end, the basic principle of the weaving method of the invention is to overconsumption of the weft yarn in a weft plane with respect to a baseline so as to produce fabric structures on one side. and / or the other in elevation or relief of the baseline.

As has been mentioned, the basic principle of the method of the invention for producing a relief on a fabric is completed by the implementation of the technique of binding specific warp yarns by means of a determined sequencing of warp threads so as to produce at least one slot. Thus, in a fabric structure obtained by over-consumption of weft yarn, thicknesses determined by the number of bonded layers of warp yarns are made so as to increase in a determined manner the mechanical strength of the part. In Figure 2, there is shown the principle of binding and loosening of warp son, by an exemplary embodiment. There is shown a chain plane, the chain being directed in the direction of the arrow 18. Six layers of level weft threads from the top '1' to the bottom of the '6' pattern are represented by circles such as Weft yarn 16. Five levels of warp yarns, represented by the wavy lines as the warp line 17 are shown. The warp threads, as will be recalled later, are distributed by a warp sequencing system which places them by opening a crowd to the various layers of weft threads. Raising and lowering the warp son according to the insertion of the different layers of weft yarn, the warp threads intertwine between the weft son in a given armor.

In the embodiment of Figure 2, there is illustrated the principle of binding or loosening of warp son that is used in the weaving process of the invention. A loosening plane 15 has been shown between the layers of '3' and '4' level weft wires. To make such a plan of loosening, the sequencing of the warp 19 which is planned to respect the sequencing of the other warp son, to connect the frames of the levels' 3 'and `4', is excluded temporarily, during the length of the Unwinding plane 15. Instead, the interlacing of the warp thread 15 to the single level weft thread '4' is performed along the length of the dislocation plane 15. Referring more to the right in FIG. Unbuckling plane 15 stops between levels '3' and '4'. To achieve the resumption of binding between the two layers, the sequencing of the warp thread 19 resumes the interleaving between the levels '3' and '4' according to the position 20. As a result, the upper half of the layers level layers '1' to '3' is separated from the lower half of the '4' to '6' level weft layers on either side of the loosening plane 15. It is noted that this split into two halves of the frame layers is given for illustrative purposes only. Any other proportion may be selected depending on the circumstances. Conversely, beyond the slackening plane 15, the sequencing of the warp yarns is programmed to fully bind the weft yarn layers together and the fabric is then thick. It is thus possible to vary the thicknesses at certain locations of the fabric as a function of the forces and mechanical stresses envisaged. The arrangement of the loosening of FIG. 2 - and it should be noted that the orientation of FIG. 2 is perpendicular to that of FIG. 1 - is particularly suitable for making the visible connection in the preform of FIG. 1 between the rising slope 10 and the flat interzone 6. The rising slope 10 is typically made by the upper group of the three weft son levels of '1' to '3' while the return 5 (Figure 1) of the frame cycle shown in FIG. 1 is produced by the lower group of the three levels of weft threads from '4' to '6' of the left part of FIG. 2 at the dislocation plane 15. The flat interzone 6 is made by unification or the binding of the six levels of weft yarns from '1' to '6' to the right of the plane 15 of FIG. 2. FIG. 3 shows a new component of a loom according to the invention which allows to achieve the overconsumption of weft yarns by raising warp yarns of the process weaving die of the invention. The new component consists of a warp lifting comb consisting of hooks whose direction is parallel to the teeth of the conventional tamping comb weaving looms of the state of the art. The function of the lifting comb is therefore to discard a selection of warp yarns from one side (lifting) or the other (lowering or lifting negative) from the baseline. The lifting comb is arranged in relation to the tamping comb. In an embodiment shown in FIG. 3, the lifting comb comprises at least one vertically movable module 26-30 disposed on the tamping comb 25. The lifting movement is carried out along the direction of the comb teeth 25 so as not to interfere with the warp threads passing through it. The lower end of the hooks 26 of the lifting comb is constituted by a horizontal return obtained for example by folding the vertical portion of the hook 26. The mounting of the lifting comb in relation to the tamping comb makes it possible in particular not to obstruct the gaps 35 between the teeth of the tamping comb.

The shape of the horizontal return of the hook 26 makes it possible to capture at least one determined thread of at least one set of warp threads in order to bring it to a level in the direction of the height in the drawing of FIG. 3 which corresponds to the weaving position of the fabric structure to which said at least one determined warp thread taken in the hook 26 considered must be. The mobile unit 26-30 is mounted on a body 29 common with the actual tamping comb 25. It has two slides 27 and 28 mounted on the common body 29 and has a bend 30 which is in contact with a lifting lever operated by a controlled actuator not shown. As a result, the group of hooks 26 of the mobile unit can rise to a predetermined height above a base web of warp yarns, passing through the tamping comb outside the lifting comb 2630.

In one embodiment, the mobile unit 26-30 is only associated with the tamping comb without being mechanically secured to it. However, its control is always associated with that of the tamping comb. In Figure 4, there is shown an arrangement with two warp son plies with a portion 36 of a tamping comb, which receives a first lower web 37 which passes through its teeth at the lower level from a sequencing system not shown, but placed to the right in Figure 4, while the weaving fabric is on the left in Figure 4. A second sheet of 38-40 warp is shown at the upper level which is based on the horizontal parts hooks 35 of the mobile module associated with the tamping comb 36. The second web 38-40 comprises only a portion 39 of at least one warp which is captured by the lifting comb 35, the lateral parts of the second web, comprising groups of warp son 38 and 40 are outside the lifting comb 35. This arrangement allows to reserve the lifting of the mobile module or lifting comb 36 a specific selection of warp son of a nap pe determined by the chain son sequencing system of the loom of the invention. The lifting comb accompanies the tamping comb in its course of packing the weft threads. However, since the ply 39 has been raised to a height determined by the lifting comb, the corresponding weft yarn will be simultaneously packed and lifted by the elevation of the ply 39. Due to the difference in position of at least one warp relative to the baseline, the weft yarn provided by a weft insertion system will be over-consumed, thereby making it possible to realize the principle underlying the weaving process of the invention. Several mobile modules are provided in one embodiment, distributed in the direction of the weft so as to make different warp yarn lifts depending on the weaving areas concerned in the netting fabric being woven.

The lifting direction relative to a baseline is described above, upwards. In one embodiment at least one lifting comb performs "negative" lifting by directing a web of warp yarns downward from a baseline. In one embodiment, the lifting comb comprises at least one module similar to the module 26-30 (Figure 2), but which is integral with the lower part of the tamping comb. In one embodiment, each hook of the lifting comb is controlled by its own actuator, so that the degree of lifting of the warp yarn and thus the subsequent over-consumption of weft yarn are controlled at the finest level of weaving, that of the chain step. Note that the lift height is arbitrary and only limited by the vertical extension of the loom. In Figure 5, the movable module 35 of Figure 4 is shown in a lifting state above its neutral position. The web 38 selected in the lifting comb or moving module 35 assumes a raised position 41, and then passes into the tamping comb 35, to reach the insertion point of wefts on the fabric being woven. The lifting of the mobile module 35 is thus continuously controlled during all the weaving, especially if the architecture of the programmed fabric provides for height variations of the structures in relief along the direction of the chain. The web portions 38 and 40 of the second web 38-40 (FIG. 4) are shown to escape from the hooks of the lifting comb 35. The tamping comb 36 located downstream of the lifting comb or mobile module 35 is not disturbed by him. The vertical extension of its teeth is calculated to cover the extension of the shed, on the one hand, opened by the sequencing system of the warp yarns from which the webs 37 and 38-40 originate, and on the other hand to perform the tamping. all levels of weft son even in over-consumption position because of the lifting of the lifting comb. It is noted that the crowd during the vertical lifting or lowering of the warp threads no longer exists and the weft is already inserted. In Figure 6, there is shown the block diagram of an embodiment of a loom according to the invention. From right to left, there is a warp supply system 45 programmed for the architecture and weave of the netting fabric, a warp yarn sequencing system 46 adapted to provide crowds to each web. of warp yarns intended for lifting combs arranged in order to realize the architecture of the netweave fabric, a system 47 for packing weft yarns and lifting warp yarns according to the invention, a system 48 for advance and storage of the netting fabric during weaving and a system 50 for tensioning the warp threads while respecting the programmed relief architecture of the fabric being woven. The system 50 for tensioning the warp yarns cooperates with the conventional system 48 for feeding and storing the netting fabric during weaving. The system 50 is designed to respect the raised disposition of the warp yarns when raised or lowered with the lifting comb on either side of the baseline. The drawing of Figure 6 is made with the height in the z direction and the warp direction in the x direction of the drawn mark. The direction of the frame is perpendicular to the plane of the drawing. It is limited to a fabric architecture comprising a flat-plate 64 for example deposited on a table of the loom of the invention and a raised portion 63 disposed in height above the flat portion 64 in the z direction. This is typically the fabric shown in the weft plane of Figure 1 in which the two crenels 2, 3 are in the raised portion 63 of the fabric of Figure 6. The loom of the invention, whatever or its type, comprises a sequencing system 46 in which lices are reserved either in the flat part 64 or in the raised part 63 in at least two groups of warp plies. In the example of FIG. 6, a first link carries an eyelet 51 which carries, to the drawing in its non-working position, a warp thread 52 coming from the feed system 45. Another link carries a eyelet 54 which carries, in the drawing in its non-working position, a warp thread 54 35 coming from the feed system 45. In the example of FIG. 6, the baseline is defined on the warp 52 defining the "flat" part 64 of the fabric, while the chains as the chain 54, output by the lifting as will be explained later, is reserved for the raised portion 63 of the fabric above said baseline. In one embodiment, the loom uses a frame sequencing system. In this case, the lists are then mobilized by one or more frames, and in particular by a first group of executives assigned to the "flat" part 64 of the fabric to which belongs 51, and a second group of frames assigned to the " in relief »63 of the fabric to which belongs 53.

In another embodiment, the sequencing system allows control of each warp independently, as in a Jacquard or other type of craft. In preparing the weaving or tucking, a lifting comb 56 is mounted on the upstream face of the tamping comb 55 in the form of a parallel set of moving modules similar to the movable module 26-30 (FIG. 3) or 35 (FIG. Figures 4 and 5). Each lifting comb as the lifting comb 56 has its own lifting program both in amplitude and in time so as to achieve a specific relief of the raised portion 63 as will be described later.

Once the lifting comb 56 is put in place on the tamping comb 55, the warp threads can then be assigned on the one hand to the lists of frames of the first type, such as section 51, reserved for weaving the flat part 64 then passed directly through the teeth of the tamping comb 55 to be finally attached to the tensioning system 50 in its portion prepared for the flat portion 64 of the fabric; and secondly to the lists of frames of the second type as the lice 53 reserved for weaving the raised part 63, then passed first in the hooks provided mobile modules of the lifting comb 56 and finally through the teeth of the tamping comb 55 to be finally attached to the tensioning system 50 in its portion prepared for the raised portion 63 of the fabric. Between the tamping system 47 and the feed and storage system of the woven fabric 48 is arranged the weft inserting system 61 which will allow insertion into the open crowds in the raised portion 63 and in the flat portion. 64 as many weft yarns as are provided in the weave of the intended fabric. The insertion of the weft yarn is done using traditional means including the shuttle and / or the lance. Each weft insertion means of the weft insertion system is disposed laterally on both sides of the loom and secured to a frame of the loom at a height corresponding to that of the height of the loom. insertion of the frame provided in the weft architecture. In one embodiment, the weft insertion means is mounted on a vertically displaceable carriage (along the z-axis) to correspond with the vertical position of the shed in which it is executing its weft insertion. It is also noted that the sequencing system has been programmed to produce heights and crowd openings depending on the architecture of the fabric.

One embodiment of the weaving method using the loom described with reference to FIG. 6 will be briefly described. After the step of preparing the feed system 45 (loading the warp reels) and the sequencing system 46 (selecting or creating the first and second types of rices), after the re-entering step comprising the 15 arrangement and preparation of the lifting comb 56 on the tamping comb 55), the sequencing system 46 opens at least one crowd with the first type of slats 51 and at least one crowd with the second type frames 53. The system Weft insertion 61 inserts the various weft threads provided. Then, the lifting comb 56 executes a programmed lifting movement 57 in the z-direction upwards of FIG. 6. As a result, the weft yarn concerned by the one or more warp yarns lifted by the lifting comb 56 is overconsumed by increasing its length from the insertion system 61 due to the lifting of the warp threads 54. Then, the tamping comb 55 executes the tamping movement 60 downstream of the loom and comes to the point packing the weft yarns in the open crowds of the sequenced and raised warp yarns. Then, the crowds are closed again by the sequencing system 46. The tamping comb 55 executes an upstream return 59. If necessary, the lifting comb 56 returns to the neutral position downwards 58 and the sequencing cycle can resume with if necessary, a modification of the lifting of one or other of the moving modules of the lifting comb 56. In another embodiment, the crowd is closed by sequencing before tamping. In any case, the crowd is closed by the vertical movement of the warp threads 35 which allows lifting of the weft thread.

In Figure 7, there is shown a graph explaining the adjustment of the lifting of different mobile modules of a lifting comb adapted to achieve a niche of the kind of slot 2 double niche fabric of Figure 1. A second lifting comb , not shown, but identical to that which will be described, should be arranged to the right in the weft direction on the tamping comb to achieve the second slot 3 of Figure 1. It will not be more described. The drawing is taken in the weft plane and the woven weft 66 is shown with a warp web corresponding to the flat portion 64 of the fabric on the loom of FIG. 6 as well as the weft yarn 65 woven with a sheet of warp son corresponding to the raised portion 63 of the fabric on the loom of Figure 6. The lifting comb provided for the weaving of the crenel as the slot 2 of the fabric of Figure 1, comprises five mobile modules referenced from 70 to 74. Each mobile module comprises a plurality of hooks having a vertical portion 67 and a horizontal hooking portion on which the warp thread 68 on the leftmost hook of FIG. direction of the frame 76. The other hooks are identical. The lifting comb 70-74 was set as follows. The first movable module on the left 70 comprises two hooks which fix the low position of the weft thread 65. Then, a movable module 71 comprises five hooks whose progressive lifts impose an upward slope from left to right to the weft thread 65. A mobile module 72, equipped with ten hooks, determines a flat portion of the slot. A mobile module 73 equipped with three hooks determines the downward slope from the left to the right of the slot. Finally, a mobile module 74 with three hooks determines the low position 65 of the weft thread. The lifting of each hook like the hooks of the mobile module 71 or the overall lifting of the mobile module as the module 72 is determined by a lifting vector. as the vector 75.

Thus, single-lift mobile modules or mobile modules with controlled hook lift are provided. Over-consumption of weft yarns is here carried out along the length of the two ascending and descending slopes in order to make the slot. The number of hooks per moving module or lifting comb is determined by construction. The number of lifting combs and their characteristics of dimensions, number and not of hooks, as well as their lifting are determined according to the architecture of the desired fabric. In Figure 8, there is shown a study fabric preform for demonstrating the embossing capabilities based on the slot provided by the invention. In Figure 8, around a flat 81, two raised portions were made: an upper portion 82 and a lower portion 83. The fabric preform is seen in section in the weft plane 80. The length in the String sense is not limited.

Several slots are arranged in each of the parts of the preform. The shape and the relative position of the slots with respect to each other are not limited in the invention. In particular, we note the presence of a triangular section slot 85 an inner slot 86 whose inclined portions are connected to two flat portions, the last of them forming the flat portion 84 of the "enclosing" slot of the lower portion 83 of the woven preform. At the upper part 82 of the woven preform, we note the constitution of two crenellations 87 in the shape of "w" reversed, and which originated on the flat part of another crenel.

It is found that the length of each embossed crenel above the "flat" portion 81 of the woven preform is not limited in the warp direction. As required, the slots formed on such a preform may have lengths in the warp direction that are different from each other, a slot being thus interrupted in the direction of the chain before the end of the preform. The niche fabric preforms thus designed are used to produce composite material parts, among which are: - profiles; - beams; - rails, runners, stiffeners and autoraidis panels (by a single integrated preform); preforms attached to another preform, by gluing or stitching to produce: a stiffener; o a composite panel.

The weaving threads are chosen from technical weaving materials whose mechanical properties are sufficient to hold the forces applied to a composite part. Among these materials, it is possible to select in particular Kevlar, glass, polyester, cotton and carbon fiber.

In the case of a carbon fiber, one can choose a free diameter of 3K or 48K in carbon filaments and the fiber can be twisted or not, whether or not gimped, assembled or not, twisted or not, wired or not.

Claims (13)

REVENDICATIONS1. A method of weaving a raised fabric, characterized in that it consists of locally producing a relief like a crenel (2, 3) by overconsumption of weft yarns by lifting warp yarns at least on one side of a determined baseline (5; 81). 2. A weaving method according to claim 1, characterized in that it consists in also performing a bonding and / or untieling (15) of warp son layers to delimit at least one slot (2, 3) in the warp direction in relief on said determined baseline (5; 81). 3. Method according to any one of claims 1 or 2, characterized in that it consists in providing an insertion of weft son to determined heights (75) and a lifting of at least one ply (38) of at least one warp determined according to the desired architecture of the fabric. 15 4. Method according to claim 3, characterized in that it consists in performing a packing of the weft son after said determined lifting step. 5. Method according to claim 4, characterized in that it consists in organizing at least one crowd by sequencing warp yarns on at least one web of at least one warp according to the lifting associated with a web of warp threads. 6. Loom for carrying out the method according to one of the preceding claims, of the kind comprising at least one packing comb (55) of weft yarns and a sequencing system (45) of warp yarns, characterized in that it comprises at least one lifting comb (56) situated in relation to the tamping comb (55) between said tamping comb and the sequencing system (45) so that at least one web (38) at least one warp yarn is raised from at least one side of a baseline (4, 7; 81) and thereby causes over-weft yarns to be fed to a weft insertion system. frames (61) at heights determined by the desired architecture of the fabric. A loom according to claim 6, characterized in that the lifting comb (56) has a plurality of movable hooks (35; 67) according to a given law of lifting at least one warp thread (68). belonging to a web (38) of selected warp threads depending on the architecture of the fabric. 8. Loom according to claim 7, characterized in that the movable hooks (35; 67) are associated in at least one movable module (2630) associated with and preferably integral with the tamping comb (25; 55) so that the lifting movement is carried out perpendicular to the pressing movement. 9. loom according to any one of claims 6 to 8, characterized in that the chain son sequencing system (46) comprises a plurality of smooth of at least two types (51, 53), each type of slats being assigned to control the crowd of a determined web of warp threads according to the desired architecture of the fabric, at least some of the slats of at least one type being controlled so as to produce binding and / or a loosening of layers of warp threads in a determined area of the fabric architecture. Embossed fabric preform, characterized in that the embossed fabric such as warp-knit fabric is obtained by the method of any one of claims 1 to 5 and that the reliefs such as slots (2, 3) are arranged on at least one side of a baseline (4, 7) in the weft plane. 11. Preform according to claim 10, characterized in that it is used to produce composite material parts comprising profiles, beams, rails, rails and stiffeners, integrated or reported and autoraidis panels. 12. Preform according to claim 10, characterized in that it is attached to another preform, by gluing or stitching to produce a stiffener, or a composite panel. 13. Preform according to any one of claims 10 to 12 characterized in that the weaving son are selected from technical weaving materials including Kevlar, glass, polyester, cotton, carbon fiber. 30