Fibrous blank having at least one break with alternating weaving

Abstract

The invention relates to a fibrous blank (100) produced by weaving and comprising at least one first break (110) separating a first woven part and a second woven part (101, 102) in the blank (100), the fibrous blank (100) being characterized in that it has an alternating transformation between a first weaving plane and a different second weaving plane.

Description

Field of the Invention

[0001] The present invention relates to a fibrous blank having at least one break. For example, the present invention relates to a fibrous blank for forming a fiber reinforcement of a turbine component, and particularly to an interblade platform or a turbine ring sector. Background Art

[0002] In order to obtain lightweight turbine components with excellent thermomechanical properties, components made of composite materials are produced in a known manner, i.e., components comprising a fiber reinforcement densified by a matrix. The use of composite materials helps to optimize the performance of the turbine, particularly by reducing the overall mass of the turbine, which helps to reduce fuel consumption and thus significantly reduce pollutant emissions.

[0003] Furthermore, ceramic matrix composites can withstand temperatures from 600°C to 1400°C. Due to their better high-temperature tolerance, ceramic matrix composites require less cooling. Since this cooling typically comes from the suction of the compressor, which affects the efficiency of the turbine, the composite materials can further improve the engine efficiency and further reduce fuel consumption.

[0004] In particular, it is known to produce fibrous blanks of components by three-dimensional weaving on a jacquard-type loom, the blanks being subsequently shaped to obtain a fiber preform of the component to be produced, which preform will be densified by a matrix.

[0005] It is known to produce breaks when weaving fibrous blanks. Such breaks allow, for example, separating two parts of the fibrous blank by unfolding a part of the fibrous blank. However, a composite component comprising a part unfolded through a break has a weak area that is free of fibers and consists only of the matrix, and there may be unwanted tensions in the fibers.

[0006] For example, in order to produce a component comprising a base (from which "legs" extend), such as an interblade platform or a π-shaped turbine ring sector, a flat fibrous blank is woven according to a conventional weaving scheme, leaving breaks. These breaks allow unfolding the parts in the blank for forming the legs to obtain a fiber preform of the component to be produced.

[0007] However, it can be found that: in the components obtained by this method, the connecting edge between the base and the legs is made substantially of the matrix and is not properly reinforced by fibers, as Figure 1 shown in region Z1. Furthermore, the ends of the legs have unequal fiber lengths, some fibers extending beyond the ends of the legs, while a part of the ends of the legs is not properly reinforced by fibers, and some fibers do not reach the ends of the legs, as Figure 1As shown in the middle region Z2. Finally, the operation of unfolding the leg portion generates excessive stress on the load-bearing fibers near the connection between the base and the leg. To overcome these problems, the yarns can be crossed at the bottom of the disconnection portion during the weaving of the blank. Such a solution is specifically proposed in document WO2013 / 088040. Thus, crossing the yarns in the region adjacent to the bottom of the disconnection portion allows them to be reinforced, facilitating the unfolding of the leg portion. In addition, the crossing of these yarns allows an increase in the swelling of the fibrous blank at the connection between the base portion and the leg portion, which allows the connection between the base and the leg to be completely filled with fibers.

[0008] However, multiple bendings of the fibers (especially at the two connections) generate undesirable stresses in the fibers of the final part belonging to both the first leg and the second leg. Summary of the Invention

[0009] Therefore, the main object of the present invention is to overcome the above-mentioned drawbacks by ensuring the easy shaping of the fibrous blank while limiting the stresses generated in the fibers of the final part.

[0010] To this end, the present invention provides a fibrous blank which is produced in one piece by three-dimensional weaving between a plurality of warp yarns extending in the longitudinal direction and a plurality of weft yarns extending in the transverse direction. The fibrous blank includes at least one first disconnection portion extending in the longitudinal direction, the first disconnection portion extending from the first longitudinal edge of the fibrous blank and separating a first woven portion and a second woven portion in the fibrous blank. The fibrous blank further includes a main woven portion which has no disconnection portion and is located in the extension of the first woven portion and the second woven portion in the longitudinal direction. The fibrous blank is characterized in that the fibrous blank has a first weaving plane and a second weaving plane different from the first weaving plane. In the first weaving plane, at least a part of the warp yarns of the first woven portion and the second woven portion cross in a crossing region adjacent to the first disconnection portion in the main woven portion. In the second weaving plane, the warp yarns of the first woven portion and the second woven portion do not cross in the region adjacent to the first disconnection portion, and the fibrous blank has an alternating transformation between the first weaving plane and the second weaving plane in the transverse direction.

[0011] Thus, the fibrous blank according to the present invention is particularly easy to shape to obtain a fiber preform of the part to be produced while limiting the stresses generated in the fibers.

[0012] In fact, the crossing of the yarns of the first knitting part and the second knitting part in the main knitting part makes the first knitting part bend easily relative to the second knitting part, and vice versa, because the change in the trajectory of the warp yarns is not too sudden and is more in line with the natural stiffness of the fibers. In addition, these yarn crossings allow an increase in the expansion of the yarns in the main knitting part, which allows for a more satisfactory fiber reinforcement in the main knitting part of the final component.

[0013] The alternating transformation of the two knitting planes allows for the easy shaping of the fiber blank and a satisfactory fiber reinforcement at the connection between the first part and the second part and the main part. By alternating the knitting planes, the friction between the yarns during knitting is limited by reducing the contact points. The congestion of the yarns within the fiber blank is also limited, as is the rigidity of the blank, which further facilitates its shaping.

[0014] Thus, in the second knitting plane, the warp yarns of the first knitting part extend in a first part of the region of the main knitting part adjacent to the first break, and the warp yarns of the second knitting part extend in a second part of the region of the main knitting part adjacent to the first break, and the first part and the second part of the region of the main knitting part adjacent to the first break are different.

[0015] According to a specific embodiment of the invention, all the warp yarns of the first knitting part and the second knitting part cross in the first knitting plane in the main knitting part.

[0016] This ensures a particularly high fiber abundance in the main knitting part and a relatively smooth trajectory of all the warp yarns in the final component. In addition, by crossing all the warp yarns, the path lengths of each warp yarn are very similar, which allows for a consistent yarn length at the ends of the first part and the second part in the final component.

[0017] According to another specific embodiment of the invention, in the first knitting plane, the warp yarns of the first knitting part and the second knitting part cross at most once in the main knitting part.

[0018] Therefore, this limits the risk of yarn damage during knitting by reducing the contact points between the fibers. In addition, it ensures that the warp yarns undergo a limited number of bends to limit the tension generated in the fibers of the final component. By crossing the warp yarns only once, an optimal bending of the warp yarns is achieved, thus achieving a compromise between the easy shaping of the blank and the limitation of the stress in the fibers of the final component.

[0019] According to another specific embodiment of the invention, the first knitting plane includes a plurality of consecutive weft yarn rows T 5n in the main knitting part, where n is between 1 and N, and the weft yarn row T 51is a weft yarn row adjacent to the first disconnection portion, and N corresponds to the number of warp yarns of the first knitting portion that cross the warp yarns of the second knitting portion, so that in the weft yarn row T 5n n warp yarns of the first knitting portion cross n warp yarns of the second knitting portion.

[0020] According to another specific embodiment of the present invention, the fiber blank includes a second disconnection portion that extends from a second longitudinal edge of the fiber blank and separates a third knitting portion and a fourth knitting portion in the fiber blank. The main knitting portion is located between the first knitting portion and the second knitting portion on the one hand, and between the third knitting portion and the fourth knitting portion on the other hand. In the second knitting plane, at least a part of the warp yarns of the third knitting portion and the fourth knitting portion cross in the main knitting portion in a crossing area adjacent to the second disconnection portion.

[0021] This specific embodiment allows the production of a fiber blank that is intended to be unfolded to form a fiber preform having a base from which two legs extend. Thus, the crossing of the yarns of the third knitting portion and the fourth knitting portion in the main knitting portion makes it easy for the third knitting portion to bend relative to the fourth knitting portion, and vice versa, to form one of the two legs. The alternating change of the two knitting planes allows maintaining the easy formability of the fiber blank and a satisfactory fiber reinforcement at the connection between the legs and the base of the final component, thanks to the alternating crossing between the warp yarns.

[0022] Preferably, in the second knitting plane, all the warp yarns of the third knitting portion and the fourth knitting portion cross in the main knitting portion. Thus, the path lengths of each warp yarn are very similar, which allows for a consistent yarn length at the ends of the legs in the final component.

[0023] Preferably, in the second knitting plane, the warp yarns of the third knitting portion and the fourth knitting portion cross at most once in the main knitting portion. In fact, it is desired to avoid having the same fiber present in both the first leg and the second leg in the final component, thus undergoing at least two significant bends and creating a significant difference in fiber length at the ends of the legs.

[0024] According to another specific embodiment of the present invention, the second knitting plane includes a plurality of consecutive weft yarn rows T 6n in the main knitting portion, where n is between 1 and N, and the weft yarn row T 61 is a weft yarn row adjacent to the second disconnection portion, and N corresponds to the number of warp yarns of the third knitting portion that cross the warp yarns of the fourth knitting portion, so that in the weft yarn row T 6n n warp yarns of the third knitting portion cross n warp yarns of the fourth knitting portion.

[0025] This ensures a regular crossing of the fibers in the cross-over area to maximize dilation while limiting the contact points between the fibers, which generate friction and an undesirable hardening of the blank.

[0026] According to another specific embodiment of the invention, the fibrous blank is used to form a fiber reinforcement of a π-shaped turbine ring sector. The fibrous blank can also be used to form a fiber reinforcement of a blade having one or more integral platforms formed by disconnection portions, or a fiber reinforcement of an aircraft engine distributor.

[0027] According to a specific embodiment of the invention, in the first weaving plane, each warp thread of the first weaving portion that crosses the warp threads of the second weaving portion crosses all the warp threads of the second weaving portion that cross the warp threads of the first weaving portion.

[0028] Conversely, in the first weaving plane, each warp thread of the second weaving portion that crosses the warp threads of the first weaving portion can cross all the warp threads of the first weaving portion that cross the warp threads of the second weaving portion.

[0029] According to a specific embodiment of the invention, in the first weaving plane, each warp thread of the first weaving portion crosses all the warp threads of the second weaving portion. Conversely, in the first weaving plane, each warp thread of the second weaving portion can cross all the warp threads of the first weaving portion.

[0030] The invention also relates to a method for manufacturing a fibrous preform for a composite part, the method comprising the following steps: - Producing a fibrous blank according to the invention, - Shaping the fibrous blank to obtain the fibrous preform, the shaping comprising at least unfolding the first weaving portion or the second weaving portion.

[0031] In the case where the fibrous blank comprises two disconnection portions as described above, the shaping of the fibrous blank can comprise: unfolding the third weaving portion or the fourth weaving portion.

[0032] Furthermore, the invention relates to a method for manufacturing a composite part, the method comprising the following steps: - Producing a fibrous preform by the method for manufacturing a fibrous preform according to the invention, and - Densifying the fibrous preform with a matrix to obtain a composite part.

[0033] Preferably, the produced part is a ceramic matrix composite part of the CMC type or an organic matrix composite part of the OMC type.

[0034] Finally, the present invention relates to the use of the method for manufacturing composite parts according to the present invention in the manufacture of turbine ring sectors. The present invention may also relate to the use of the method for manufacturing composite parts in the manufacture of blades or distributors having one or more integral platforms. Description of the Drawings

[0035] Figure 1 is a schematic view of a part obtained by a prior art method, showing the organization of fibers in the matrix.

[0036] Figure 2 is a schematic illustration of a fiber blank according to the present invention.

[0037] Figure 3 is Figure 2 a schematic cross-sectional view of the fiber blank of

[0038] Figure 4 is Figure 2 a schematic cross-sectional view of the fiber blank of

[0039] Figure 5 is a schematic view of a fiber preform obtained by shaping the fiber blank of Figure 2

[0040] Figure 6 is Figure 5 a schematic cross-sectional view of the fiber preform of

[0041] Figure 7 is Figure 5 a schematic cross-sectional view of the fiber preform of

[0042] Figure 8 is obtained by Figure 5 densification of the fiber preform of

[0043] Figure 9 a schematic view of a part obtained by the method according to the present invention, showing the organization of fibers in the matrix. Detailed Description

[0044] Figures 2 to 4 An example of a fiber blank 100 according to the present invention is schematically shown.

[0045] The fiber blank 100 is produced by three-dimensional weaving between a plurality of warp layers and a plurality of weft layers. Here, "three-dimensional weaving" or "3D weaving" refers to a weaving method by which at least some warp yarns bind the weft yarns on a plurality of weft layers. A role reversal between the warp and weft yarns is possible.

[0046] The fibrous preform can for example have: a multi - satin weave (i.e., a fabric obtained by three - dimensional weaving using multiple weft yarn layers), where the basic weave of each layer is equivalent to a conventional satin weave, but has certain weaving points that bind the weft yarn layers together. The fibrous preform can also for example have: an interlock weave (i.e., a fabric obtained by three - dimensional weaving), where each warp yarn layer binds multiple weft yarn layers of all the yarns of the same warp yarn column having the same movement in the weaving plane. Other three - dimensional weaving methods are conceivable, such as a weave having a multi - plain weave. Different multi - layer weaving methods that can be used to form the fibrous preform are described in WO 2006 / 136755.

[0047] The fibrous preform 100 is preferably produced using a jacquard - type loom. Such a loom is described for example in the document FR 3 047 744 A1.

[0048] The fibrous preform 100 extends in the longitudinal direction D along the warp direction L between a first longitudinal edge 100a and a second longitudinal edge 100b. The fibrous preform 100 extends in the transverse direction D along the weft direction T between a first transverse edge 100c and a second transverse edge 100d. The fibrous preform 100 extends in thickness along a thickness direction D perpendicular to the longitudinal direction D L and the transverse direction D T between a first surface 100e and a second surface 100f. E

[0049] The fibrous preform 100 includes at least one first break 110 and at least one second break 120 extending in the longitudinal direction D L and the transverse direction D T Preferably, the first break 110 and the second break 120 are located in the same plane perpendicular to the thickness direction D E

[0050] The first break 110 extends in the longitudinal direction D L from the first longitudinal edge 100a of the fibrous preform 100 to the bottom 110a of the break. The first break 110 is open at the first longitudinal edge 100a, i.e., the first break 110 opens at the first longitudinal edge 100a of the fibrous preform 100. The first break 110 extends in the transverse direction D T between the first transverse edge 100c and the second transverse edge 100d. Preferably, the first break 110 is open at the first transverse edge 100c and the second transverse edge 100d, i.e., the first break 110 opens at the first transverse edge 100c and the second transverse edge 100d.

[0051] The second break 120 extends in the longitudinal direction DL extends from the second longitudinal edge 100b of the fibrous blank 100 to the bottom 120b of the cut. The second cut 120 is open on the second longitudinal edge 100b, that is, the second cut 120 opens on the second longitudinal edge 100b of the fibrous blank 100. The second cut 120 extends in the transverse direction D T between the first transverse edge 100c and the second transverse edge 100d. Preferably, the second cut 120 is open on the first transverse edge 100c and the second transverse edge 100d, that is, the second cut 120 opens on the first transverse edge 100c and the second transverse edge 100d.

[0052] The sum of the lengths of the first cut 110 and the second cut 120 in the longitudinal direction D L is less than the total length of the fibrous blank 100 in the longitudinal direction D L Therefore, the fibrous blank 100 includes a main woven part 105, and the main woven part 105 does not include any cuts. The main woven part 105 of the fibrous blank 100 extends in the longitudinal direction D L between the bottom 110a of the first cut 110 and the bottom 120b of the second cut 120. The main woven part 105 of the fibrous blank 100 extends in the transverse direction D T between the first transverse edge 100c and the second transverse edge 100d of the fibrous blank 100. The main woven part 105 of the fibrous blank 100 extends in the thickness direction D E between the first surface 100e and the second surface 100f of the fibrous blank 100.

[0053] The first cut 110 separates the first woven part 101 and the second woven part 102 of the fibrous blank 100. Therefore, the first woven part 101 of the fibrous blank 100 extends in the longitudinal direction D L between the first longitudinal edge 100a and the main woven part 105 of the fibrous blank 100. The first woven part 101 of the fibrous blank 100 extends in the thickness direction D E between the first surface 100e and the first cut 110 of the fibrous blank 100. Similarly, the second woven part 102 of the fibrous blank 100 extends in the longitudinal direction D L between the first longitudinal edge 100a and the main woven part 105 of the fibrous blank 100. The second woven part 102 of the fibrous blank 100 extends in the thickness direction D E between the second surface 100f and the first cut 110 of the fibrous blank 100. Preferably, the first woven part 101 and the second woven part 102 of the fibrous blank 100 extend in the transverse direction D Textends between the first lateral edge 100c and the second lateral edge 100d of the fibrous blank 100. Preferably, the first braided portion 101 and the second braided portion 102 are joined to each other only by the main braided portion 105.

[0054] The second disconnection portion 120 separates the third braided portion 103 and the fourth braided portion 104 of the fibrous blank 100. Thus, the third braided portion 103 of the fibrous blank 100 extends in the longitudinal direction D L extends between the second longitudinal edge 100b of the fibrous blank 100 and the main braided portion 105. The third braided portion 103 of the fibrous blank 100 extends in the thickness direction D E extends between the first surface 100e of the fibrous blank 100 and the second disconnection portion 120. Similarly, the fourth braided portion 104 of the fibrous blank 100 extends in the longitudinal direction D L extends between the second longitudinal edge 100b of the fibrous blank 100 and the main braided portion 105. The fourth braided portion 104 of the fibrous blank 100 extends in the thickness direction D E extends between the second surface 100f of the fibrous blank 100 and the second disconnection portion 120. Preferably, the third braided portion 103 and the fourth braided portion 104 of the fibrous blank 100 extend in the lateral direction D T extends between the first lateral edge 100c and the second lateral edge 100d of the fibrous blank 100. Preferably, the third braided portion 103 and the fourth braided portion 104 are joined to each other only by the main braided portion 105.

[0055] The fibrous blank 100 extends in the lateral direction D T includes an alternating transformation between a first braided plane and a second braided plane, Figure 3 in which the first braided plane is schematically shown, Figure 4 in which the second braided plane is schematically shown. The first braided plane and the second braided plane are different. Figure 3 the first braided plane of Figure 4 and the second braided plane of Figure 2 correspond to the cross-section of the fibrous blank 100 shown along a plane perpendicular to the lateral direction D T and schematically represent the braiding between the warp threads and the weft threads and the crossing between the warp threads. Figure 3 and Figure 4 the braided planes shown in are schematic diagrams, so the number of warp threads and the number of weft threads represented are lower than the actual number of warp threads and the actual number of weft threads.

[0056] In Figure 3 the first braided plane of the fibrous blank 100 shown, the first warp thread c 11 、c 12 、c 13 、c14 The weft yarns t1 of the first woven portion 101 of the fibrous blank 100 are joined together, while the second warp yarns c 15 、c 16 、c 17 、c 18 The weft yarns t2 of the second woven portion 102 of the fibrous blank 100 are joined together. Then, the first warp yarn and the second warp yarns c 11 、c 12 、c 13 、c 14 、c 15 、c 16 、c 17 、c 18 The weft yarns t5 and t6 of the main woven portion 105 are joined together.

[0057] In Figure 3 the example of the first woven plane shown, all the first warp yarns c from the first woven portion 101 11 、c 12 、c 13 、c 14 cross with all the second warp yarns c from the second woven portion 102 15 、c 16 、c 17 、c 18 Cross. Thus, all the first warp yarns or the second warp yarns have a trajectory with a length similar to that of the other first warp yarns or the second warp yarns, which allows the legs of the final component to be filled more regularly with the fibers. Of course, if only a part of the first warp yarns c from the first woven portion 101 11 、c 12 、c 13 、c 14 cross with the second warp yarns c from the second woven portion 102 15 、c 16 、c 17 、c 18 cross, or if only a part of the second warp yarns c from the second woven portion 102 15 、c 16 、c 17 、c 18 cross with the first warp yarns c from the first woven portion 101 11 、c 12 、c 13 、c 14 cross, it is obvious that the scope of the present invention is not departed from either.

[0058] The first warp yarns c from the first woven portion 101 11 、c 12 、c 13 、c14 and the second warp yarn c from the second knitting part 102 15 、c 16 、c 17 、c 18 cross in the first crossing area 105a of the main knitting part 105. The first crossing area 105a at least partially includes a plurality of weft yarn rows T 51 、T 52 、…、T 57 , each weft yarn row includes the first warp yarn c from the first knitting part 101 11 、c 12 、c 13 、c 14 and the second warp yarn c from the second knitting part 102 15 、c 16 、c 17 、c 18 and at least one crossing between them. In particular, the first crossing area 105a extends in the longitudinal direction D L between the weft yarn row T 51 (on one hand) and the weft yarn row T 57 (on the other hand), the weft yarn row T 51 includes at least one crossing closest to the first disconnection part 110 (i.e., closest to the bottom 110a of the disconnection part 110), and the weft yarn row T 57 includes at least one crossing closest to the second disconnection part 120 (i.e., closest to the bottom 120b of the disconnection part 120 and thus farthest from the first disconnection part 110). The first crossing area 105a does not include: all or part of the weft yarn row including at least one crossing located between the first disconnection part 110 and the weft yarn row T closest to the first disconnection part 110 51 , and the first crossing area 105a does not include: all or part of the weft yarn row including at least one crossing located between the second disconnection part 120 and the weft yarn row T closest to the second disconnection part 120 57 .

[0059] Preferably, the first crossing area 105a is limited to a reduced area of the main knitting part 105, in which each weft yarn row T 51 to T 57 includes: the first warp yarn c from the first knitting part 101 11 、c 12 、c 13 、c 14 and the second warp yarn c from the second knitting part 102 15 、c 16 、c 17 、c 18At least one crossover therebetween. Thus, each weft yarn row T that is at least partially present in the first crossover region 105a 51 to T 57 includes: the first warp yarns c 11 、c 12 、c 13 、c 14 from the first knitting part 101 and the second warp yarns c 15 、c 16 、c 17 、c 18 therebetween.

[0060] In Figure 3 the example of the first knitting plane shown, the first crossover region 105a of the main knitting part 105 is adjacent to the first break 110, i.e., adjacent to the bottom 110a of the break 110. In particular, this means that: the end weft yarn row T 51 of the main knitting part 105 that is closest to the first break 110 (i.e., closest to the bottom 110a of the break 110) includes the first warp yarns c 11 、c 12 、c 13 、c 14 from the first knitting part 101 and the second warp yarns c 15 、c 16 、c 17 、c 18 therebetween. Preferably, the weft yarn rows T 61 to T 67 that are present in the main knitting part 105 and are closest to the second break 120 (i.e., closest to the bottom 120b of the second break 120) do not have the first warp yarns c 11 、c 12 、c 13 、c 14 from the first knitting part 101 and the second warp yarns c 15 、c 16 、c 17 、c 18 therebetween.

[0061] Preferably, as Figure 3 shown, each first warp yarn c 15 、c 16 、c 17 、c 18 that crosses the second warp yarns c 11 、c 12 、c 13 、c 14 is crossed by each second warp yarn c15 , c 16 , c 17 , c 18 crosses once. On the contrary, each second warp yarn c 11 , c 12 , c 13 , c 14 crossed with the first warp yarn c 15 , c 16 , c 17 , c 18 crosses each first warp yarn c 11 , c 12 , c 13 , c 14 once.

[0062] Preferably, as Figure 3 shown, the first warp yarns c 11 , c 12 , c 13 , c 14 from the first knitting part 101 and the second warp yarns c 15 , c 16 , c 17 , c 18 from the second knitting part 102 are regularly crossed in the first knitting plane as follows: first cross the warp yarn closest to the first disconnection part 110, and then gradually cross the warp yarns farther and farther away from the first disconnection part 110. Therefore, in the first weft yarn row T 51 closest to the first disconnection part 110 and belonging to the first crossing area 105a, a single first warp yarn c 14 from the first part 101 crosses with a single second warp yarn c 15 from the second knitting part 102: the first warp yarn c 14 closest to the first disconnection part 110 crosses with the second warp yarn c 15 closest to the first disconnection part 110. In the second weft yarn row T 52 closest to the first disconnection part 110 and belonging to the first crossing area 105a, only two first warp yarns c 14 , c 13 from the first part 101 cross with only two second warp yarns c 15 , c 16 from the second knitting part 102: the first warp yarn c 14 crosses with the second warp yarn c 16 , and the first warp yarn c 13 crosses with the second warp yarn c 15 . In the third weft yarn row T 53Among them, only three first warp yarns c from the first part 101 14 , c 13 , c 12 cross with only three second warp yarns c from the second knitting part 102 15 , c 16 , c 17 : The first warp yarn c 14 crosses with the second warp yarn c 17 , the first warp yarn c 13 crosses with the second warp yarn c 16 , and the first warp yarn c 12 crosses with the second warp yarn c 15 .

[0063] Generally, T 5n represents the nth weft yarn row closest to the first break 110 in the main part 105, where n is between 1 and N (including the end values), and N is the number of the first yarns c 15 , c 16 , c 17 , c 18 crossing with the second yarns c 11 , c 12 , c 13 , c 14 in the first crossing area 105a, or N is the number of the second yarns c 11 , c 12 , c 13 , c 14 crossing with the first yarns c 15 , c 16 , c 17 , c 18 in the first crossing area 105a. In the example shown in Figure 3 , the value of the quantity N is 4. Therefore, in each row T 5n , n first warp yarns from the first knitting part 101 cross with n second warp yarns from the second knitting part 102. In the example shown in Figure 3 , for n = N, in the fourth row T 54 , there are 4 first warp yarns c 15 , c 16 , c 17 , c 18 from the first knitting part 101 crossing with 4 second warp yarns c 11 , c 12 , c 13 , c 14 .

[0064] In addition, in each row T 5n among them, the first warp yarn c1N-i crosses the second warp yarn c 1N+n-i where i is between 0 and n - 1 (including the end values). Thus, in the Figure 3 example shown, in column T 52 , i.e., n = 2, the increment i = 0 clearly shows that the first warp yarn c 14-0 (i.e., c 14 ) crosses the second warp yarn c 14+2-0 (i.e., c 16 ), and the increment i = 1 clearly shows that the first warp yarn c 14-1 (i.e., c 13 ) crosses the second warp yarn c 14+2-1 (i.e., c 15 ).

[0065] Once the weft yarn column T 5N (corresponding to column T Figure 3 in 54 ) is reached, the number of yarn crossings in each weft yarn column regularly decreases until the end of the first crossing region 105a farthest from the first disconnection portion 110. T 5N+m represents the (N + m)-th weft yarn column closest to the first disconnection portion 110 in the main portion 105, where m is between 1 and N - 1 (including the end values), and N is the number of the first yarns c 15 , c 16 , c 17 , c 18 that cross the second yarn c 11 , c 12 , c 13 , c 14 in the first crossing region 105a or N is the number of the second yarns c 11 , c 12 , c 13 , c 14 that cross the first yarns c 15 , c 16 , c 17 , c 18 in the first crossing region 105a. Thus, in each column T 5N+m , N - m first warp yarns from the first knitting portion cross N - m second warp yarns from the second knitting portion. In the Figure 3 example shown, for m = 2, in column T 56 , there are 2 first warp yarns c 17 , c 18 from the first knitting portion 101 that cross 2 second warp yarns c 11 , c 12 from the second knitting portion 102.

[0066] Preferably, in the first weaving plane, the first warp yarns c 15 、c 16 、c 17 、c 18 from the first weaving part 101 that have crossed with the second warp yarns c 11 、c 12 、c 13 、c 14 from the second weaving part 102 bind the weft yarn t4 of the fourth weaving part 104 of the fiber blank 100 together, and do not bind the weft yarn t3 of the third weaving part 103 of the fiber blank 100, so as to limit the curvature of these first warp yarns c 11 、c 12 、c 13 、c 14 that have crossed. For the same reason, preferably, the second warp yarns c 11 、c 12 、c 13 、c 14 from the second weaving part 102 that have crossed with the first warp yarns c 15 、c 16 、c 17 、c 18 from the first weaving part 101 bind the weft yarn t3 of the third weaving part 103 of the fiber blank 100 together, and do not bind the weft yarn t4 of the fourth weaving part 104 of the fiber blank 100.

[0067] In Figure 4 the second weaving plane of the fiber blank 100 shown, the third warp yarns c 21 、c 22 、c 23 、c 24 bind the weft yarn t3 of the third weaving part 103 of the fiber blank 100 together, and the fourth warp yarns c 25 、c 26 、c 27 、c 28 bind the weft yarn t4 of the fourth weaving part 104 of the fiber blank 100 together. Then, the third warp yarns and the fourth warp yarns c 21 、c 22 、c 23 、c 24 、c 25 、c 26 、c 27 、c 28 bind the weft yarns t5 and t6 of the main weaving part 105 together.

[0068] In Figure 4 the example of the second weaving plane shown, all the third warp yarns c from the third weaving part 10321 and c 22 and c 23 and c 24 cross with all the fourth warp yarns c 25 and c 26 and c 27 and c 28 from the fourth knitting section 104. Thus, all the third or fourth warp yarns have a trajectory with a length similar to that of the other third or fourth warp yarns, which allows the ends of the legs of the final component to be filled more regularly with fibers. Of course, if only a part of the third warp yarns c 21 and c 22 and c 23 and c 24 from the third knitting section 103 cross with the fourth warp yarns c 25 and c 26 and c 27 and c 28 from the fourth knitting section 104, or if only a part of the fourth warp yarns c 25 and c 26 and c 27 and c 28 from the fourth knitting section 104 cross with the third warp yarns c 21 and c 22 and c 23 and c 24 from the third knitting section 103, it is obvious that it does not depart from the scope of the present invention either.

[0069] The third warp yarns c 21 and c 22 and c 23 and c 24 from the third knitting section 103 and the fourth warp yarns c 25 and c 26 and c 27 and c 28 from the fourth knitting section 104 cross in the second crossing area 105b of the main knitting section 105. The second crossing area 105b at least partially includes a plurality of weft yarn rows T 61 and T 62 and … and T 67 , and each weft yarn row includes: the third warp yarns c 21 and c 22 and c 23 and c 24 from the third knitting section 103 and the fourth warp yarns c 25 and c 26 and c 27 and c 28at least one crossing between. In particular, the second crossing region 105b extends along the longitudinal direction D L in the weft yarn row T 61 (on the one hand) and the weft yarn row T 67 (on the other hand), and the weft yarn row T 61 includes: at least one crossing closest to the second disconnection portion 120 (i.e., closest to the bottom 120b of the disconnection portion 120), and the weft yarn row T 67 includes: at least one crossing closest to the first disconnection portion 110 (i.e., closest to the bottom 110a of the disconnection portion 110 and thus farthest from the second disconnection portion 120). The second crossing region 105b does not include: all or part of the weft yarn row including at least one crossing between the second disconnection portion 120 and the weft yarn row closest to the second disconnection portion 120, and the second crossing region 105b does not include: all or part of the weft yarn row including at least one crossing between the first disconnection portion 110 and the weft yarn row closest to the first disconnection portion 110 61 67

[0070] Preferably, the second crossing region 105b is limited to a reduced region of the main knitting portion 105, in which each weft yarn row T 61 to T 67 includes: at least one crossing between the third warp yarn c 21 、c 22 、c 23 、c 24 from the third knitting portion 103 and the fourth warp yarn c 25 、c 26 、c 27 、c 28 from the fourth knitting portion 104. Therefore, each weft yarn row T 61 to T 67 at least partially present in the second crossing region 105b includes: at least one crossing between the third warp yarn c 21 、c 22 、c 23 、c 24 from the third knitting portion 103 and the fourth warp yarn c 25 、c 26 、c 27 、c 28 from the fourth knitting portion 104

[0071] at Figure 4 ​​In the example of the second knitting plane shown, the second crossing area 105b of the main knitting part 105 is adjacent to the second disconnecting part 120, that is, adjacent to the bottom 120b of the disconnecting part 120. In particular, this means that the end weft yarn row T of the main knitting part 105 that is closest to the second disconnecting part 120 (i.e., closest to the bottom 120b of the disconnecting part 120) 61 includes: the third warp yarn c from the third knitting part 103 21 、c 22 、c 23 、c 24 and the fourth warp yarn c from the fourth knitting part 104 25 、c 26 、c 27 、c 28 There is at least one crossing between them. Preferably, the weft yarn rows T 51 to T 57 in the main knitting part 105 that are closest to the first disconnecting part 110 (i.e., the bottom 110a of the first disconnecting part 110) 21 、c 22 、c 23 、c 24 and the fourth warp yarn c from the fourth knitting part 104 25 、c 26 、c 27 、c 28 do not have crossings between them.

[0072] Preferably, as Figure 4 shown, each third warp yarn c 25 、c 26 、c 27 、c 28 that crosses the fourth warp yarn c 21 、c 22 、c 23 、c 24 crosses each fourth warp yarn c 25 、c 26 、c 27 、c 28 once. On the contrary, each fourth warp yarn c 21 、c 22 、c 23 、c 24 that crosses the third warp yarn c 25 、c 26 、c 27 、c 28 crosses each third warp yarn c 21 、c 22 、c 23 、c 24 once.

[0073] Preferably, as Figure 4 shown, the third warp yarns c 21 , c 22 , c 23 , c 24 from the third knitting part 103 and the fourth warp yarns c 25 , c 26 , c 27 , c 28 from the fourth knitting part 104 cross regularly in the second knitting plane as follows: first cross the warp yarns closest to the second disconnection part 120, and then gradually cross the warp yarns that are farther and farther away from the second disconnection part 120. Therefore, in the first weft yarn row T 61 closest to the second disconnection part 120 and belonging to the second crossing area 105b, a single third warp yarn c 24 from the third part 103 crosses with a single fourth warp yarn c 25 from the fourth knitting part 104: the third warp yarn c 24 closest to the second disconnection part 120 crosses with the fourth warp yarn c 25 closest to the second disconnection part 120. In the second weft yarn row T 62 closest to the second disconnection part 120 and belonging to the second crossing area 105b, only two third warp yarns c 24 , c 23 from the third part 103 cross with only two fourth warp yarns c 25 , c 26 from the fourth knitting part 104: the third warp yarn c 24 crosses with the fourth warp yarn c 26 , while the third warp yarn c 23 crosses with the fourth warp yarn c 25 . In the third weft yarn row T 63 closest to the second disconnection part 120 and belonging to the second crossing area 105b, only three third warp yarns c 24 , c 23 , c 22 from the third part 103 cross with only three fourth warp yarns c 25 , c 26 , c 27 from the fourth knitting part 104: the third warp yarn c 24 crosses with the fourth warp yarn c 27 , the third warp yarn c 23 crosses with the fourth warp yarn c 26 , and the third warp yarn c 22 crosses with the fourth warp yarn c 25 .

[0074] Generally, T6n Represents the nth weft yarn row closest to the second disconnection part 120 in the main part 105, where n is between 1 and N (including the end values), and N is the number of the third yarn c 25 、c 26 、c 27 、c 28 crossing the fourth yarn c 21 、c 22 、c 23 、c 24 in the second crossing area 105b, or N is the number of the fourth yarn c 21 、c 22 、c 23 、c 24 crossing the third yarn c 25 、c 26 、c 27 、c 28 in the second crossing area 105b. In the example shown in Figure 4 , the value of the number N is 4. Therefore, in each column T 6n , n warp yarns from the third knitting part 103 cross n warp yarns from the fourth knitting part 104. In the example shown in Figure 4 , for n = N, in the fourth column T 64 , there are 4 first warp yarns c 25 、c 26 、c 27 、c 28 from the third knitting part 103 crossing the 4 fourth warp yarns c 21 、c 22 、c 23 、c 24 from the fourth knitting part 104.

[0075] In addition, in each column T 6n , the third warp yarn c 2N-i crosses the fourth warp yarn c 2N+n-i , where i is between 0 and n - 1 (including the end values). Therefore, in the example shown in Figure 4 , in the column T 62 , that is, n = 2, the increment i = 0 clearly shows that the third warp yarn c 24-0 (i.e., c 24 ) crosses the fourth warp yarn c 24+2-0 (i.e., c 26 ), and the increment i = 1 clearly shows that the third warp yarn c 24-1 (i.e., c 23 ) crosses the fourth warp yarn c 24+2-1 (i.e., c 25 ).

[0076] Once weft row T is reached 6N (exist Figure 4 Corresponding to column T 64 ), the number of yarn crossings in each weft yarn row decreases regularly until the end of the second crossing area 105b farthest from the second breaking portion 120. 6N+m represents the (N+m)th weft yarn row closest to the second break 120 in the main portion 105, where m is between 1 and N-1 (including the end values), and N is the number of weft yarns intersecting with the fourth yarn c in the second crossing region 105b. 25 、c 26 、c 27 、c 28 Crossed third yarn c 21 、c 22 、c 23 、c 24 The number or N is the number of yarns c in the second crossing region 105b. 21 、c 22 、c 23 、c 24 Crossed fourth yarn c 25 、c 26 、c 27 、c 28 Therefore, in each column T 6N+m In the case of Nm third warp yarns from the third weaving portion, Nm fourth warp yarns from the fourth weaving portion are crossed. Figure 4 In the example shown, for m=2, in column T 66 There are two fourth warp yarns c from the fourth weaving portion 104. 27 、c 28 The two third warp yarns c from the third weaving portion 103 are crossed 21 、c 22 .

[0077] Preferably, in the second weaving plane, the fourth warp yarn c from the fourth weaving portion 102 has been 25 、c 26 、c 27 、c 28 The crossed third warp yarns c from the third weaving portion 103 21 、c 22 、c 23 、c 24 The weft yarns t2 of the second woven portion 102 of the fiber blank 100 are combined together, and the weft yarns t1 of the first woven portion 101 of the fiber blank 100 are not combined to limit the third warp yarns c that have crossed. 21 、c 22 、c 23 、c 24The curvature. For the same reason, preferably, the third warp yarns c from the third weaving section 103 21 、c 22 、c 23 、c 24 that have crossed with the fourth warp yarns c from the fourth weaving section 104 25 、c 26 、c 27 、c 28 bind together the weft yarns t1 of the first weaving section 101 of the fiber blank 100 and do not bind the weft yarns t2 of the second weaving section 102 of the fiber blank 100.

[0078] Preferably, the first plane and the second weaving plane regularly and alternately change along the transverse direction D T to facilitate the future shaping of the entire width of the fiber blank 100 along the transverse direction D T Of course, if the first plane and the second weaving plane irregularly and alternately change along the transverse direction D T it is obvious that it also does not depart from the scope of the present invention. Preferably, in the transverse direction D T one first weaving plane does not immediately follow another first weaving plane. Preferably, in the transverse direction D T one second weaving plane does not immediately follow another second weaving plane.

[0079] Preferably, in the first weaving section 101, the second weaving section 102, the third weaving section 103 and the fourth weaving section 104, there is no crossing between the warp yarns to limit the curvature and tension in the fibers belonging to the fiber blank 100.

[0080] Preferably, the fiber blank 100 according to the present invention does not include a layer outlet, which means that the sum of the number of warp yarn layers in the first part 101 and the number of warp yarn layers in the second part 102 corresponds to the number of warp yarn layers in the main part 105 and corresponds to the sum of the number of warp yarn layers in the third part 103 and the number of warp yarn layers in the fourth part 104.

[0081] Preferably, the fiber blank 100 corresponds to a "dry" fiber texture, i.e., not impregnated with resin or the like. The fiber blank 100 may include various types of multiple yarns, especially ceramic or carbon fiber yarns or mixtures of these yarns. Preferably, the fiber blank 100 may be made of silicon carbide fibers. Generally, the fiber blank 100 may also be manufactured from fibers made of the following materials: alumina, mullite, silica, aluminosilicate, borosilicate, carbon or mixtures of several of these materials.

[0082] As Figure 5As shown, the fiber blank 100 thus obtained is then shaped to obtain a fiber preform 10 in the following manner: the first braided part 101 and the second braided part 102 are separated by a first disconnection part 110, and the third braided part 103 and the fourth braided part 104 are separated by a second disconnection part 120. This shaping operation is greatly simplified on the one hand by the warp cross in the main braided part 105 near the bottoms 110a and 120b of the disconnection parts 110 and 120, and on the other hand by the alternating transformation of the position of the cross region 105a or 105b of the main braided part 105 between a first braiding plane and a second braiding plane.

[0083] In Figures 5 to 9 the example shown, it is desired to produce a π-shaped part 1, which includes a base 2, and a first leg 3 and a second leg 4 extending from the base 2. The part 1 is preferably a turbine ring sector or an interblade platform. If it is desired to produce another composite part from the fiber blank according to the present invention, it is clearly also not outside the scope of the present invention.

[0084] Therefore, in order to form the fiber preform 30 of the first leg 3 (which is used to form the fiber reinforcement of the first leg 3), the first braided part 101 of the fiber blank 100 is unfolded to arrange it perpendicular to the second braided part 102 and the main braided part 105. In order to form the fiber preform 40 of the second leg 4 (which is used to form the fiber reinforcement of the second leg 4), the third braided part 103 of the fiber blank 100 is unfolded to arrange it perpendicular to the fourth braided part 104 and the main braided part 105. Finally, the fiber preform 20 of the base 2 is formed by the second braided part 102, the fourth braided part 104 and the main braided part 105 of the fiber blank 100.

[0085] Therefore, as Figure 5 shown, the fiber preform 10 includes: a base preform 20, a first leg preform 30 extending from the base preform 20, and a second leg preform 40 extending from the base preform 20.

[0086] Preferably, the length and width of the base preform 20 of the fiber preform 10, the lengths of the leg preforms 30 and 40, and the spacing between the two leg preforms 30 and 40 basically correspond respectively to the length and width of the base 2 of the part 1 to be obtained, the lengths of the legs 3 and 4, and the spacing between the two legs 3 and 4, as Figure 8 schematically shown in.

[0087] Once the fiber preform 10 is obtained, the preform 10 is densified by a matrix to obtain the part 1 including the fiber reinforcement constituted by the preform 10.

[0088] The fiber preform can be consolidated or densified by chemical vapor infiltration (referred to as "CVI") of the matrix in a known gas manner. The fiber preform corresponding to the fiber reinforcement of the part to be produced is placed in a furnace, and a reactive gas phase is introduced into the furnace. The pressure and temperature present in the furnace and the composition of the gas phase are selected so as to allow the gas phase to diffuse within the pores of the preform to form at least a part of the matrix by depositing a solid material resulting from the decomposition of the components of the gas phase or the reaction between several components at the core of the material in contact with the fibers, which is different from the pressure and temperature conditions of the CVD method ("chemical vapor deposition") that only causes deposition on the surface of the material. The formation of a SiC matrix can be achieved by using methyltrichlorosilane (MTS) and obtaining SiC by decomposition of MTS.

[0089] Densification using a combination of gas and liquid paths can be carried out in a known manner to facilitate implementation and limit costs and manufacturing cycles while obtaining satisfactory properties for the intended use. In this configuration, the consolidation of the fiber preform is carried out by gas as described above, and then the fiber preform is impregnated with a suspension or slurry (referred to as "slurry casting") containing, for example, SiC particles and an organic binder, and subsequently infiltrated with liquid silicon ("melt infiltration"). Densification can be carried out in a known manner by resin injection molding or "resin transfer molding" (abbreviated as "RTM") or by suspension injection molding or "slurry transfer molding" (abbreviated as "STM"). As Figure 6 shown in the example, the fiber preform 10, previously consolidated or unconsolidated by gas, is disposed in a cavity defined by a first part 61 and a second part 62 of a mold 60. The cavity has the shape of the part to be manufactured, which at least roughly has the shape of the part 1 to be manufactured.

[0090] Conventionally, a slurry 6 or resin loaded with matrix precursor particles is injected into the cavity receiving the fiber preform 10 to pass through the fiber preform 10 by applying a pressure gradient P. The mold 6 for injecting the slurry 6 includes a filter 63 at the outlet hole of the slurry 6 in the mold 60, thereby allowing any matrix precursor particles to be retained in the mold 60 and impregnating the fiber preform 10 as the matrix precursor particles are deposited in the mold 60 in the case of the slurry.

[0091] Densification can also be achieved in a known manner by membrane injection, as Figure 7 shown. This injection mode allows full control of the amount of resin or slurry injected, thus ensuring an accurate and appropriate fiber volume ratio. Therefore, the mechanical properties of the parts manufactured in this way are improved, and the differences between parts are reduced.

[0092] The fiber preform 10 for forming the fiber reinforcement of the part 1 is arranged in the mold 70. In particular, the fiber preform 10 can be arranged directly on the lower surface of the impregnation chamber 71. This lower surface of the impregnation chamber 71 can include a filter ( Figure 7 not shown in

[0093] The mold 70 includes on the one hand an impregnation chamber 71 in which the fiber preform 10 is arranged to be densified by a matrix by injecting an impregnation fluid 8, and the mold 70 includes on the other hand a compaction chamber 72 into which a compression fluid 9 is injected to apply pressure to the fiber preform 10 during its densification by the matrix. The impregnation chamber 71 and the compaction chamber 72 are separated by a flexible membrane 73. The membrane 73 allows pressure to be applied to the fiber preform 10 mounted in the impregnation chamber 71. The compression fluid 9 applies a pressure Q to the membrane 73, and the membrane 73 deforms and thus in turn applies pressure to the fiber preform 10.

[0094] Preferably, as Figure 7 shown, the membrane fits against the surfaces of the leg preforms 30 and 40 of the fiber preform 10 and of the base preform 20 located between the leg preforms 30 and 40, while the surface of the base preform 20 opposite the leg preforms 30 and 40 abuts against one of the walls of the impregnation chamber 71 opposite the membrane 73. An insert 74 can be used to facilitate the impregnation of the fiber preform 10 of the part 1. As Figure 7 shown, for example, the resin 8 can be injected into the impregnation chamber 71 through an inlet opening, and the compression liquid 9 can be injected into the compaction chamber 72 through an inlet opening.

[0095] Depending on the dimensions, thickness and shape of the part 1 to be manufactured, different injection sequences for the compression and impregnation fluids will be preferred.

[0096] A compression fluid (such as water) is injected into the compaction chamber to apply pressure to the flexible membrane. Thus, the flexible membrane applies pressure to the fiber preform, allowing the impregnation fluid to penetrate into the preform.

[0097] Then, while maintaining the pressure applied by the membrane, the preform is heat-treated to form a matrix in the pores of the fiber preform.

[0098] When the densification step is completed, a composite part 1 is obtained, as Figure 8 and Figure 9 shown, whose fiber reinforcement is constituted by the fiber preform 10 and whose shape generally corresponds to the part 1 to be manufactured. Trimming or light machining steps can be carried out on the produced part to obtain the part 1 to be produced. In addition, other elements can be mounted or welded to the produced part to obtain the part 1 to be produced.

[0099] The obtained component can be a component made of ceramic matrix composite (CMC) or organic matrix composite (OMC). Preferably, the obtained composite component is a component made of ceramic matrix composite (CMC) of SiC / SiC type.

[0100] Figure 9 Figure showing the fiber distribution in the matrix in the component obtained by the method of the present invention, where the fibers cross in region Z3 and do not cross in region Z4. As Figure 9 shown in region Z5 in, the fibers of the obtained component 1 well fill the angle between the base 2 and the legs 3 and 4. As compared with the component obtained by the prior art method as Figure 1 shown, the improvement is significant.

[0101] The expression "between... and..." should be understood to include the end values.

Claims

1. A fiber blank (100), which is produced in one piece by three-dimensional weaving between a plurality of warp yarns extending along a longitudinal direction (D L ), and a plurality of weft yarns (t1, t2, t3, t4, t5, t6) extending along a transverse direction (D T ). The fiber blank (100) includes at least one first disconnection portion (110, 120) extending along the longitudinal direction (D L ). The first disconnection portion (110) extends from a first longitudinal edge (100a) of the fiber blank (100) and separates a first woven portion and a second woven portion (101, 102) in the fiber blank (100). The fiber blank (100) further includes a main woven portion (105) that has no disconnection portion and is located in the extensions of the first woven portion and the second woven portion (101, 102) along the longitudinal direction (D L ). The fiber blank (100) is characterized in that the fiber blank has a first weaving plane and a second weaving plane different from the first weaving plane. In the first weaving plane, at least a part of the warp yarns (c 11 , c 12 , c 13 , c 14 , c 15 , c 16 , c 17 , c 18 ), of the first weaving part and the second weaving part (101, 102), cross in a crossing area (105a) adjacent to the first disconnection part (110) in the main weaving part (105). In the second weaving plane, the warp yarns (c 11 , c 12 , c 13 , c 14 , c 15 , c 16 , c 17 , c 18 ) of the first weaving part and the second weaving part (101, 102) do not cross in an area adjacent to the first disconnection part (110), and the fiber blank (100) has an alternating transformation between the first weaving plane and the second weaving plane along the transverse direction (D T ).

2. The fibrous blank (100) according to claim 1, wherein, In the first knitting plane, all the warp threads (c 11 , c 12 , c 13 , c 14 , c 15 , c 16 , c 17 , c 18 ) of the first knitting part and the second knitting part (101, 102) cross in the main knitting part (105).

3. The fibrous blank (100) according to claim 1 or 2, wherein, In the first knitting plane, the warp yarns (c 11 , c 12 , c 13 , c 14 , c 15 , c 16 , c 17 , c 18 ) of the first knitting part and the second knitting part (101, 102) cross at most once in the main knitting part (105).

4. The fibrous blank (100) according to any one of claims 1 to 3, wherein, The first knitting plane includes a plurality of consecutive weft yarn rows T in the main knitting part (105). 5n (T 51 , T 52 , T 53 , T 54 , T 55 , T 56 , T 57 ), where n is between 1 and N, and the weft yarn row T 51 is the weft yarn row adjacent to the first disconnection part (110), and N corresponds to the number of warp yarns (c 15 , c 16 , c 17 , c 18 ) of the first knitting part (101) that cross the warp yarns (c 11 , c 12 , c 13 , c 14 ) of the second knitting part (102), so that in the weft yarn row T 5n , n warp yarns (c 11 , c 12 , c 13 , c 14 ) of the first knitting part (101) cross n warp yarns (c 15 , c 16 , c 17 , c 18 ) of the second knitting part (102).

5. The fibrous blank (100) according to any one of claims 1 to 4, the fibrous blank (100) comprising a second disconnection portion (120) extending from a second longitudinal edge (100b) of the fibrous blank (100) and separating a third woven portion and a fourth woven portion (103, 104) in the fibrous blank (100), the main woven portion (105) being located between the first woven portion and the second woven portion (101, 102), or between the third woven portion and the fourth woven portion (103, 104), in the second weaving plane, at least a portion of the warp yarns (c 21 , c 22 , c 23 , c 24 , c 25 , c 26 , c 27 , c 28 ), c of the third woven portion and the fourth woven portion cross in the main woven portion (105) in a crossing region (105b) adjacent to the second disconnection portion (120).

6. The fibrous blank (100) according to claim 5, wherein, The second knitting plane includes a plurality of consecutive weft yarn rows T in the main knitting part (105). 6n (T 61 , T 62 , T 63 , T 64 , T 65 , T 66 , T 67 ), where n is between 1 and N. The weft yarn row T 61 is the weft yarn row adjacent to the second disconnection part (120). N corresponds to the number of warp yarns (c 25 , c 26 , c 27 , c 28 ) of the third knitting part (103) that cross the warp yarns (c 21 , c 22 , c 23 , c 24 ) of the fourth knitting part (104). Thus, in the weft yarn row T 6n , n warp yarns (c 21 , c 22 , c 23 , c 24 ) of the third knitting part (103) cross n warp yarns (c 25 , c 26 , c 27 , c 28 ) of the fourth knitting part (104).

7. The fibrous blank (100) according to claim 5 or 6, wherein, The fiber blank (100) is used to form a fiber reinforcement for a π-shaped turbine ring sector.

8. The fibrous blank (100) according to any one of claims 1 to 7, wherein, In the first braiding plane, each warp yarn of the first braiding part (101) that crosses the warp yarns of the second braiding part (102) crosses all the warp yarns of the second braiding part (102) that cross the warp yarns of the first braiding part (101).

9. The fibrous blank (100) according to any one of claims 1 to 8, wherein, In the first braiding plane, each warp yarn of the first braiding part (101) crosses all the warp yarns of the second braiding part (102).

10. A method for manufacturing a fiber preform (10) for a composite component, the method comprising the following steps: Producing a fiber blank (100) according to any one of claims 1 to 9, Shaping the fiber blank (100) to obtain the fiber preform (10), the shaping at least including unfolding the first braiding part (101) or the second braiding part.

11. A method for manufacturing a composite material part (1), the method Comprising the following steps: Producing a fiber preform (10) by the method for manufacturing a fiber preform according to claim 10, and Densifying the fiber preform (10) with a matrix to obtain the composite component (1).

12. Use of the method according to claim 11 in the manufacture of a turbine ring sector.

Images