A fiber blank with at least one fiber having alternating knitted breaks

Abstract

The invention relates to a fibre blank (100) produced by braiding and comprising at least one first break (110) separating a first braided portion (101) and a second braided portion (102) in the blank (100), the fibre blank (100) being characterised in that it has an alternating change between a first braiding plane and a different second braiding plane.

Description

Technical Field

[0001] This invention relates to a fiber preform having at least one break. For example, this invention relates to a fiber preform for forming fiber reinforcements for turbine components, and particularly to inter-blade platforms or turbine ring sectors. Background Technology

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

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

[0004] In particular, it is known to produce fiber preforms for components by three-dimensional weaving on a jacquard loom, the preforms being then shaped to obtain fiber preforms of the components to be produced, which are then densified by a matrix.

[0005] It is known that breaks are created during the weaving of fiber preforms. Such breaks allow for the separation of two parts of the fiber preform, for example, by unfolding a portion of the preform. However, composite parts that include the unfolded portion through the break have weak areas consisting of no fibers and only the matrix, and undesirable tensions may exist within the fibers.

[0006] For example, to produce components that include a base from which "legs" extend, such as an inter-blade platform or a π-shaped turbine ring sector, a flat fiber preform is woven according to a conventional weaving scheme, leaving breaks. These breaks allow the portions of the preform used to form the legs to be unfolded to obtain a fiber preform of the component to be produced.

[0007] However, it can be observed that in parts obtained by this method, the connecting edge between the base and the leg is essentially made of the matrix and is not properly reinforced with fibers, such as... Figure 1 As shown in region Z1. Furthermore, the ends of the legs have unequal fiber lengths; some fibers extend beyond the end of the leg, while a portion of the end of the leg is not adequately reinforced by fibers, and some fibers do not reach the end of the leg, such as... Figure 1As shown in region Z2. Finally, the operation of unfolding the leg portion can generate excessive stress on the stressed fibers near the connection between the base and the leg. To overcome these problems, the yarns can be crossed at the bottom of the break during the weaving of the fabric. Such a solution is specifically proposed in document WO2013 / 088040. Therefore, crossing the yarns in the region near the bottom of the break allows them to be reinforced, thus facilitating the unfolding of the leg portion. In addition, these yarn crossings allow for increased expansion of the fiber fabric at the connection between the base and the leg portion, which allows the connection between the base and the leg to be completely filled with fibers.

[0008] However, repeated bending of the fibers (especially at the two joints) can generate undesirable stresses in the fibers of the final components belonging to both the first and second legs. Summary of the Invention

[0009] Therefore, the main objective of this invention is to overcome the aforementioned disadvantages by ensuring the ease of forming the fiber preform while limiting the stress generated in the fibers of the final part.

[0010] To this end, the present invention provides a fiber preform produced in single piece by three-dimensional weaving between multiple warp yarns extending in a longitudinal direction and multiple weft yarns extending in a transverse direction. The fiber preform includes at least one first break extending in the longitudinal direction, the first break extending from a first longitudinal edge of the fiber preform and separating a first woven portion and a second woven portion within the fiber preform. The fiber preform also includes a main woven portion without a break and located in the longitudinal direction within the extensions of the first and second woven portions. The fiber preform is characterized in that it has a first weaving plane and a second weaving plane different from the first weaving plane. In the first weaving plane, at least a portion of the warp yarns of the first and second woven portions cross in the main woven portion in an intersection region adjacent to the first break. In the second weaving plane, the warp yarns of the first and second woven portions do not cross in the region adjacent to the first break. Furthermore, the fiber preform has an alternation between the first and second weaving planes in the transverse direction.

[0011] Therefore, the fiber preform according to the invention is particularly easy to form into fiber preforms of the parts to be produced, while limiting the stress generated in the fibers.

[0012] In practice, the crossing of the yarns in the first and second braided sections within the main braided section makes the first braided section more flexible than the second, and vice versa, because the change in the warp yarn trajectory is less abrupt and better conforms to the natural stiffness of the fiber. Furthermore, these yarn crossings allow for increased yarn expansion in the main braided section, which allows for more satisfactory fiber reinforcement in the main braided section of the final component.

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

[0014] Therefore, in the second weaving plane, the warp yarns of the first weaving portion extend in the first part of the region adjacent to the first break in the main weaving portion, and the warp yarns of the second weaving portion extend in the second part of the region adjacent to the first break in the main weaving portion. The first part and the second part of the region adjacent to the first break in the main weaving portion are different.

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

[0016] This ensures a particularly high fiber abundance in the main weave section and a relatively smooth path for all warp yarns in the final section. Furthermore, by interlacing all warp yarns, the path length of each warp yarn is very similar, which allows for consistent yarn lengths at the ends of the first and second sections in the final section.

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

[0018] Therefore, this limits the risk of yarn damage during weaving by reducing the contact points between fibers. Furthermore, it ensures that the warp yarns undergo a limited number of bends to limit the tension generated in the fibers of the final part. Optimal warp bending is achieved by crossing the warp yarns only once, thus striking a trade-off between ease of shaping the fabric and limiting stress in the fibers of the final part.

[0019] According to another specific embodiment of the present invention, the first knitting plane includes a plurality of continuous weft yarn rows T in the main knitting section. 5n Where n is between 1 and N, the weft yarn column T 51It is the weft yarn column adjacent to the first break, N corresponds to the number of warp yarns in the first knitting section that intersect with the warp yarns of the second knitting section, so that in the weft yarn column T 5n In the process, the n warp yarns of the first weaving section intersect with the n warp yarns of the second weaving section.

[0020] According to another specific embodiment of the invention, the fiber preform includes a second break portion extending from a second longitudinal edge of the fiber preform and separating a third braided portion and a fourth braided portion in the fiber preform. The main braided portion is located between the first braided portion and the second braided portion on one hand, and between the third braided portion and the fourth braided portion on the other hand. In the second braiding plane, at least a portion of the warp yarns of the third braided portion and the fourth braided portion cross in the main braided portion in an intersection region adjacent to the second break portion.

[0021] This particular embodiment allows for the production of a fiber preform for unfolding to form a fiber preform having a base from which two legs extend. Therefore, the crossing of the yarns in the third and fourth braided sections within the main braided section makes the third braided section easier to bend relative to the fourth braided section, and vice versa, to form one of the two legs. The alternating transformation of the two braided planes allows for maintaining the ease of forming the fiber preform and satisfactory fiber reinforcement at the junction of the legs and base of the final part, thanks to the alternating crossing of the warp yarns.

[0022] Preferably, in the second weaving plane, all warp yarns of the third and fourth weaving sections cross in the main weaving section. Therefore, the path lengths of each warp yarn are very similar, which allows for consistent yarn lengths at the ends of the legs in the final part.

[0023] Preferably, in the second weaving plane, the warp yarns of the third and fourth weaving sections cross at most once in the main weaving section. In practice, it is desirable to avoid the same fiber simultaneously existing in the first and second legs in the final part, thus avoiding at least two significant bends and resulting in a significant difference in fiber length at the ends of the legs.

[0024] According to another specific embodiment of the invention, the second weaving plane includes a plurality of continuous weft yarn rows T in the main weaving section. 6n Where n is between 1 and N, the weft yarn column T 61 It is the weft yarn column adjacent to the second break, N corresponds to the number of warp yarns in the third knitting section that intersect with the warp yarns of the fourth knitting section, so that in the weft yarn column T 6n In the process, the n warp yarns of the third weaving section intersect with the n warp yarns of the fourth weaving section.

[0025] This ensures regular fiber crossing in the cross regions to maximize expansion while limiting contact points between fibers that would generate friction and undesirable hardening of the blank.

[0026] According to another specific embodiment of the invention, the fiber preform is used to form a fiber reinforcement for a π-shaped turbine ring sector. The fiber preform can also be used to form a fiber reinforcement for a blade having one or more integrated platforms formed by a break in the circumference, or a fiber reinforcement for an aero-engine distributor.

[0027] According to a specific embodiment of the present invention, in the first weaving plane, each warp yarn of the first weaving portion that intersects with the warp yarns of the second weaving portion intersects with all the warp yarns of the second weaving portion that intersect with the warp yarns of the first weaving portion.

[0028] Conversely, in the first weaving plane, each warp yarn of the second weaving section that intersects with the warp yarns of the first weaving section can intersect with all the warp yarns of the first weaving section that intersect with the warp yarns of the second weaving section.

[0029] According to a specific embodiment of the invention, in the first weaving plane, each warp yarn of the first weaving portion intersects with all the warp yarns of the second weaving portion. Conversely, in the first weaving plane, each warp yarn of the second weaving portion may intersect with all the warp yarns of the first weaving portion.

[0030] The present invention also relates to a method for manufacturing fiber preforms for composite material components, the method comprising the following steps:

[0031] - Producing the fiber preform according to the present invention

[0032] - The fiber preform is shaped to obtain the fiber preform, the shaping comprising at least unfolding a first woven portion or a second woven portion.

[0033] When the fiber preform includes the two disconnected portions as described above, the forming of the fiber preform may include unfolding a third or fourth braided portion.

[0034] Furthermore, the present invention relates to a method for manufacturing composite material parts, the method comprising the following steps:

[0035] -The method for manufacturing fiber preforms according to the present invention produces fiber preforms, and

[0036] - Densify the fiber preform through a matrix to obtain a composite component.

[0037] Preferably, the manufactured component is a CMC type ceramic matrix composite component or an OMC type organic matrix composite component.

[0038] Finally, the present invention relates to the use of the method for manufacturing composite material components 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 material components in the manufacture of blades or distributors having one or more integrated platforms. Attached Figure Description

[0039] Figure 1 It is a schematic diagram of a component obtained according to existing technical methods, showing the structure of fibers in the matrix.

[0040] Figure 2 This is a schematic illustration of the fiber preform according to the present invention.

[0041] Figure 3 yes Figure 2 A schematic cross-sectional view of the fiber preform, showing the first weaving plane.

[0042] Figure 4 yes Figure 2 A schematic cross-sectional view of the fiber preform, showing the second weaving plane.

[0043] Figure 5 Through forming Figure 2 A schematic diagram of a fiber preform obtained from fiber blanks.

[0044] Figure 6 yes Figure 5 A schematic cross-sectional view of a fiber preform in a rigid tool.

[0045] Figure 7 yes Figure 5 A schematic cross-sectional view of a fiber preform in a tool that includes a flexible membrane.

[0046] Figure 8 Through Figure 5 A schematic diagram of a component obtained by densifying a fiber preform.

[0047] Figure 9 This is a schematic diagram of a component obtained according to the method of the present invention, showing the structure of fibers in the matrix. Detailed Implementation

[0048] Figures 2 to 4 An example of a fiber preform 100 according to the present invention is shown schematically.

[0049] Fiber preform 100 is produced by three-dimensional weaving between multiple warp and weft layers. Here, "three-dimensional weaving" or "3D weaving" refers to a weaving method in which at least some warp yarns combine with weft yarns on multiple weft layers. Reversal of roles between warp and weft yarns is possible.

[0050] The fiber prefabricated material can, for example, have: multi-satin weave (i.e., a fabric obtained by three-dimensional weaving using multiple weft layers), where the basic weave of each layer is equivalent to a conventional satin weave, but with certain weave points that bind the weft layers together. The fiber prefabricated material can also, for example, have: interlocking weave (i.e., a fabric obtained by three-dimensional weaving), where each warp layer combines multiple weft layers with all yarns of the same warp column having the same movement in the weave plane. Other three-dimensional weaving methods are conceivable, such as weaves with multiple plain weaves. Different multi-layer weaving methods that can be used to form the fiber prefabricated material are described in WO 2006 / 136755.

[0051] The fiber preform 100 is preferably produced using a jacquard loom. Such a loom is described, for example, in document FR 3 047 744 A1.

[0052] Fiber preform 100 along the longitudinal direction D in the warp direction L It extends between the first longitudinal edge 100a and the second longitudinal edge 100b. The fiber preform 100 extends in the weft direction along the transverse direction D. T It extends between the first transverse edge 100c and the second transverse edge 100d. The fiber preform 100 has a thickness perpendicular to the longitudinal direction D. L and horizontal direction D T thickness direction D E It extends between the first surface 100e and the second surface 100f.

[0053] Fiber preform 100 includes: in the longitudinal direction D L and horizontal direction D T At least one first break portion 110 and at least one second break portion 120 extending upwards. Preferably, the first break portion 110 and the second break portion 120 are located in the thickness direction D. E On the same vertical plane.

[0054] The first break section 110 is along the longitudinal direction D L The first break 110 extends from the first longitudinal edge 100a of the fiber preform 100 to the bottom 110a of the first break portion 110. The first break portion 110 is open at the first longitudinal edge 100a, meaning it opens at the first longitudinal edge 100a of the fiber preform 100. The first break portion 110 extends along the transverse direction D. TIt extends between the first lateral edge 100c and the second lateral edge 100d. Preferably, the first break portion 110 is open at the first lateral edge 100c and the second lateral edge 100d, that is, the first break portion 110 is open at the first lateral edge 100c and the second lateral edge 100d.

[0055] The second disconnection 120 is along the longitudinal direction D L The second break 120 extends from the second longitudinal edge 100b of the fiber preform 100 to the bottom 120b of the second break 120. The second break 120 is open at the second longitudinal edge 100b, meaning it opens at the second longitudinal edge 100b of the fiber preform 100. The second break 120 extends along the transverse direction D. T It extends between the first lateral edge 100c and the second lateral edge 100d. Preferably, the second break portion 120 is open on the first lateral edge 100c and the second lateral edge 100d, that is, the second break portion 120 is open on the first lateral edge 100c and the second lateral edge 100d.

[0056] The first break portion 110 and the second break portion 120 are along the longitudinal direction D L The sum of the lengths is less than 100 D of the fiber preform along the longitudinal direction. L The total length. Therefore, the fiber preform 100 includes a main braided portion 105, which does not include any breaks. The main braided portion 105 of the fiber preform 100 is along the longitudinal direction D. L It extends between the bottom 110a of the first break 110 and the bottom 120b of the second break 120. The main braided portion 105 of the fiber preform 100 extends along the transverse direction D. T It extends between the first transverse edge 100c and the second transverse edge 100d of the fiber preform 100. The main braided portion 105 of the fiber preform 100 extends along the thickness direction D. E It extends between the first surface 100e and the second surface 100f of the fiber preform 100.

[0057] The first break portion 110 separates the first braided portion 101 and the second braided portion 102 of the fiber preform 100. Therefore, the first braided portion 101 of the fiber preform 100 is separated along the longitudinal direction D. L It extends between the first longitudinal edge 100a of the fiber preform 100 and the main braided portion 105. The first braided portion 101 of the fiber preform 100 extends along the thickness direction D. E It extends between the first surface 100e and the first break 110 of the fiber preform 100. Similarly, the second braided portion 102 of the fiber preform 100 extends along the longitudinal direction D. LThe second braided portion 102 of the fiber preform 100 extends between the first longitudinal edge 100a and the main braided portion 105. E It extends between the second surface 100f of the fiber preform 100 and the first break portion 110. Preferably, the first braided portion 101 and the second braided portion 102 of the fiber preform 100 are along the transverse direction D. T It extends between the first transverse edge 100c and the second transverse edge 100d of the fiber preform 100. Preferably, the first braided portion 101 and the second braided portion 102 are joined to each other only through the main braided portion 105.

[0058] The second break 120 separates the third braided portion 103 and the fourth braided portion 104 of the fiber preform 100. Therefore, the third braided portion 103 of the fiber preform 100 extends along the longitudinal direction D... L The third braided portion 103 of the fiber preform 100 extends between the second longitudinal edge 100b and the main braided portion 105. The third braided portion 103 of the fiber preform 100 extends along the thickness direction D. E It extends between the first surface 100e and the second break 120 of the fiber preform 100. Similarly, the fourth braided portion 104 of the fiber preform 100 extends along the longitudinal direction D. L It extends between the second longitudinal edge 100b of the fiber preform 100 and the main braided portion 105. The fourth braided portion 104 of the fiber preform 100 extends along the thickness direction D. E Extending between the second surface 100f and the second break portion 120 of the fiber preform 100. Preferably, the third braided portion 103 and the fourth braided portion 104 of the fiber preform 100 are along the transverse direction D. T It extends between the first transverse edge 100c and the second transverse edge 100d of the fiber preform 100. Preferably, the third braided portion 103 and the fourth braided portion 104 are joined to each other only through the main braided portion 105.

[0059] Fiber preform 100 along the transverse direction D T This includes the alternating transformation between the first and second weaving planes. Figure 3 The first weave plane is schematically shown in the diagram. Figure 4 The second weave plane is schematically shown. The first and second weave planes are different. Figure 3 The first weave plane and Figure 4 The second weave plane corresponds to Figure 2 The fiber preform 100 shown has a transverse direction D T A cross-section of a vertical plane, schematically showing the weaving between warp and weft yarns and the crossings between warp yarns. Figure 3 and Figure 4The weaving plane shown is a schematic diagram, therefore the number of warp and weft yarns represented is lower than the actual number of warp and weft yarns.

[0060] exist Figure 3 In the first weaving plane of the fiber preform 100 shown, the first warp yarn c 11 c 12 c 13 c 14 The weft yarns t1 of the first braided portion 101 of the fiber preform 100 are joined together, while the second warp yarns c 15 c 16 c 17 c 18 The weft yarns t2 of the second braided portion 102 of the fiber preform 100 are joined together. Then, the first warp yarn and the second warp yarn c... 11 c 12 c 13 c 14 c 15 c 16 c 17 c 18 Combine the weft yarns t5 and t6 of the main knitting section 105.

[0061] exist Figure 3 In the example of the first weave plane shown, all the first warp yarns c from the first weave section 101 11 c 12 c 13 c 14 With all the second warp yarns c from the second weaving section 102 15 c 16 c 17 c 18 Crossing. Therefore, all first or second warp yarns have a track length similar to that of the other first or second warp yarns, which allows for more regular filling of the ends of the legs of the final part with fibers. Of course, if only the first warp yarns c from the first weave section 101... 11 c 12 c 13 c 14 A portion of the second warp yarn c from the second weaving section 102 15 c 16 c 17 c 18 Cross, or if only the second warp c from the second weave section 102 15 c 16 c 17 c 18 A portion of the first warp yarn c from the first weaving section 101 11 c12 c 13 c 14 If there is any overlap, it is clearly not outside the scope of this invention.

[0062] The first warp c from the first weaving section 101 11 c 12 c 13 c 14 and the second warp c from the second weaving section 102 15 c 16 c 17 c 18 The weft yarns cross in the first crossing region 105a of the main knitting section 105. The first crossing region 105a at least partially includes multiple weft yarn rows T. 51 T 52 ... T 57 Each weft row includes the first warp yarn c from the first weaving section 101. 11 c 12 c 13 c 14 and the second warp c from the second weaving section 102 15 c 16 c 17 c 18 At least one intersection between them. Specifically, the first intersection region 105a is along the longitudinal direction D. L In the weft yarn T 51 (On the one hand) and weft yarn T 57 (On the other hand) extending between, weft yarn T 51 Including at least one cross closest to the first break 110 (i.e., closest to the bottom 110a of the first break 110), weft yarn row T 57 This includes at least one intersection closest to the second break 120 (i.e., closest to the bottom 120b of the second break 120, and therefore furthest from the first break 110). The first intersection region 105a does not include: the weft yarn column T located at the first break 110 and closest to the first break 110. 51 Between, including all or part of at least one intersecting weft yarn column, and the first intersecting region 105a does not include: the weft yarn column T located at the second break 120 and the closest to the second break 120. 57 All or part of the weft yarns between, including at least one intersecting weft yarn column.

[0063] Preferably, the first cross region 105a is limited to a reduced area of ​​the main knitting portion 105, in which each weft yarn column T 51 To T 57 Includes: the first warp c from the first weaving section 101 11c 12 c 13 c 14 and the second warp c from the second weaving section 102 15 c 16 c 17 c 18 At least one intersection between them. Therefore, each weft yarn column T is at least partially present in the first intersection region 105a. 51 To T 57 Includes: the first warp c from the first weaving section 101 11 c 12 c 13 c 14 and the second warp c from the second weaving section 102 15 c 16 c 17 c 18 At least one intersection between them.

[0064] exist Figure 3 In the example of the first knitting plane shown, the first cross region 105a of the main knitting portion 105 is adjacent to the first break portion 110, that is, adjacent to the bottom 110a of the first break portion 110. Specifically, this means that the end weft yarn column T of the main knitting portion 105 closest to the first break portion 110 (i.e., closest to the bottom 110a of the first break portion 110) 51 Including the first warp c from the first weaving section 101 11 c 12 c 13 c 14 and the second warp c from the second weaving section 102 15 c 16 c 17 c 18 At least one intersection between them. Preferably, the weft yarn column T present in the main knitting section 105 closest to the second break 120 (i.e., closest to the bottom 120b of the second break 120). 61 To T 67 The first warp c does not have a first weave section 101 11 c 12 c 13 c 14 and the second warp c from the second weaving section 102 15 c 16 c 17 c 18 The intersection between them.

[0065] Preferably, such as Figure 3 As shown, with the second warp c 15 c16 c 17 c 18 Each first warp c crosses 11 c 12 c 13 c 14 All with each second warp c 15 c 16 c 17 c 18 Cross once. Conversely, with the first warp c 11 c 12 c 13 c 14 Each second warp c crosses 15 c 16 c 17 c 18 All with each first warp c 11 c 12 c 13 c 14 Cross once.

[0066] Preferably, such as Figure 3 As shown, the first warp yarn c from the first weaving section 101 11 c 12 c 13 c 14 With the second warp c from the second weaving section 102 15 c 16 c 17 c 18 The crossing is carried out regularly in the first weft yarn plane in the following manner: first, the warp yarns closest to the first break 110 are crossed, and then the warp yarns further and further away from the first break 110 are gradually crossed. Therefore, in the first weft yarn column T, which belongs to the first crossing region 105a and is closest to the first break 110, 51 In the middle, a single warp c from the first warp of the first part 101 14 With the second warp c from the second weaving section 102 15 Crossover: The first warp c closest to the first break 110 14 The second warp c closest to the first break 110 15 Crossing. In the second weft yarn column T, which belongs to the first crossing region 105a and is closest to the first break 110, ... 52 In the middle, only two warp threads c from the first part 101 are present. 14 c 13 With only two second warp yarns c from the second weaving section 102 15 c 16 Crossover: First warp c 14With the second warp c 16 Crossed, and the first warp c 13 With the second warp c 15 Crossing. In the third weft yarn row T, which belongs to the first crossing region 105a and is closest to the first break 110. 53 In the middle, only three of the first warp threads c from the first part 101 14 c 13 c 12 With only three second warp yarns from the second weaving section 102 15 c 16 c 17 Crossover: First warp c 14 With the second warp c 17 Cross, first warp c 13 With the second warp c 16 Crossed, and the first warp c 12 With the second warp c 15 cross.

[0067] Typically, T 5n This represents the nth weft yarn column closest to the first break 110 in the main knitting section 105, where n is between 1 and N (inclusive), and N is the number of yarns that intersects with the second yarn c in the first cross region 105a. 15 c 16 c 17 c 18 The first intersecting yarn c 11 c 12 c 13 c 14 The quantity or N is in the first intersection region 105a with the first yarn c 11 c 12 c 13 c 14 The second cross yarn c 15 c 16 c 17 c 18 The quantity. In Figure 3 In the example shown, the quantity N is 4. Therefore, in each column T 5n In this process, n first warp yarns from the first weaving section 101 intersect with n second warp yarns from the second weaving section 102. Figure 3 In the example shown, for n=N, in the fourth column T 54 In the middle, there are 4 second warp yarns c from the second weaving section 102. 15 c 16 c 17 c 18 The four first warp yarns c from the first weaving section 101 cross each other. 11c 12 c 13 c 14 .

[0068] In addition, in each column T 5n In the middle, the first warp yarn c 1N-i With the second warp c 1N+n-i Cross, where i lies between 0 and n-1 (inclusive). Therefore, in Figure 3 In the example shown, in column T 52 In the middle, that is, n=2, the increment i=0 clearly indicates the first warp c 14-0 (i.e., c) 14 ) and the second warp c 14+2-0 (i.e., c) 16 The intersection and the increment i=1 clearly indicate the first warp c 14-1 (i.e., c) 13 ) and the second warp c 14+2-1 (i.e., c) 15 )cross.

[0069] Once the weft yarn T is reached 5N (exist Figure 3 The middle corresponds to column T 54 The number of yarn crossings in each weft row decreases regularly until the end of the first crossing region 105a, which is furthest from the first break 110. 5N+m This represents the (N+m)th weft yarn column in the main knitting section 105 closest to the first break 110, where m is between 1 and N-1 (inclusive), and N is the number of yarns in the first cross region 105a that intersects with the second yarn c. 15 c 16 c 17 c 18 The first intersecting yarn c 11 c 12 c 13 c 14 The quantity or N is in the first intersection region 105a with the first yarn c 11 c 12 c 13 c 14 The second cross yarn c 15 c 16 c 17 c 18 The quantity. Therefore, in each column T 5N+m In this process, Nm first warp yarns from the first weaving section intersect with Nm second warp yarns from the second weaving section. Figure 3 In the example shown, for m=2, in column T 56 In the middle, there are two second warp yarns c from the second weaving section 102.17 c 18 The two first warp yarns c from the first weaving section 101 cross each other. 11 c 12 .

[0070] Preferably, in the first weaving plane, the second warp yarn c from the second weaving section 102 has already been... 15 c 16 c 17 c 18 The first warp c from the first weave section 101 crosses over. 11 c 12 c 13 c 14 The weft yarns t4 of the fourth braided portion 104 of the fiber preform 100 are joined together, while the weft yarns t3 of the third braided portion 103 of the fiber preform 100 are not joined together, in order to restrict these already crossed first warp yarns c. 11 c 12 c 13 c 14 The curvature. For the same reason, preferably, it has been connected with the first warp yarn c from the first weaving section 101. 11 c 12 c 13 c 14 The second warp c from the second weave section 102 crosses over. 15 c 16 c 17 c 18 The weft yarns t3 of the third braided portion 103 of the fiber preform 100 are combined together, while the weft yarns t4 of the fourth braided portion 104 of the fiber preform 100 are not combined.

[0071] exist Figure 4 In the second weaving plane of the fiber preform 100 shown, the third warp yarn c 21 c 22 c 23 c 24 The weft yarns t3 of the third weaving section 103 of the fiber preform 100 are combined together, and the fourth warp yarn c 25 c 26 c 27 c 28 The weft yarns t4 of the fourth weaving section 104 of the fiber preform 100 are combined. Then, the third warp yarn and the fourth warp yarn c 21 c 22 c 23 c 24 c 25 c 26 c 27 c28 Combine the weft yarns t5 and t6 of the main knitting section 105.

[0072] exist Figure 4 In the example of the second weave plane shown, all the third warp yarns c from the third weave section 103 21 c 22 c 23 c 24 With all the fourth warp yarns c from the fourth weaving section 104 25 c 26 c 27 c 28 Crossing. Therefore, all third or fourth warp yarns have a track length similar to that of the other third or fourth warp yarns, which allows for more regular filling of the ends of the legs of the final part with fibers. Of course, if only the third warp yarns c from the third weave section 103... 21 c 22 c 23 c 24 A portion of the fourth warp yarn c from the fourth weaving section 104 25 c 26 c 27 c 28 Cross, or if only the fourth warp c from the fourth weave section 104 25 c 26 c 27 c 28 A portion of the third warp yarn c from the third weaving section 103 21 c 22 c 23 c 24 If there is any overlap, it is clearly not outside the scope of this invention.

[0073] The third warp c from the third weaving section 103 21 c 22 c 23 c 24 and the fourth warp c from the fourth weaving section 104 25 c 26 c 27 c 28 The crosses occur in the second cross region 105b of the main knitting section 105. The second cross region 105b at least partially comprises multiple weft yarn rows T. 61 T 62 ... T 67 Each weft yarn column includes: the third warp yarn c from the third weaving section 103. 21 c 22 c 23 c24 and the fourth warp c from the fourth weaving section 104 25 c 26 c 27 c 28 At least one intersection between them. In particular, the second intersection region 105b is along the longitudinal direction D. L In the weft yarn T 61 (On the one hand) and weft yarn T 67 (On the other hand) extending between, weft yarn T 61 Includes: at least one cross closest to the second break 120 (i.e., the bottom 120b closest to the second break 120), and weft yarn column T 67 Includes at least one intersection closest to the first break 110 (i.e., closest to the bottom 110a of the first break 110, and therefore furthest from the second break 120). The second intersection region 105b does not include: the weft yarn column T located at the second break 120 and closest to the second break 120. 61 The second crossing region 105b does not include: the weft yarn column T located at the first break 110 and the weft yarn column T closest to the first break 110. 67 All or part of the weft yarns between, including at least one intersecting weft yarn column.

[0074] Preferably, the second cross region 105b is limited to a reduced area of ​​the main knitting portion 105, in which each weft yarn column T 61 To T 67 Includes: the third warp yarn c from the third weaving section 103 21 c 22 c 23 c 24 and the fourth warp c from the fourth weaving section 104 25 c 26 c 27 c 28 At least one intersection between them. Therefore, each weft yarn column T is at least partially present in the second intersection region 105b. 61 To T 67 Includes: the third warp yarn c from the third weaving section 103 21 c 22 c 23 c 24 and the fourth warp c from the fourth weaving section 104 25 c 26 c 27 c 28 At least one intersection between them.

[0075] exist Figure 4In the example of the second knitting plane shown, the second cross region 105b of the main knitting portion 105 is adjacent to the second break portion 120, that is, adjacent to the bottom 120b of the second break portion 120. Specifically, this means that the end weft yarn column T of the main knitting portion 105 closest to the second break portion 120 (i.e., closest to the bottom 120b of the second break portion 120) 61 Includes: the third warp yarn c from the third weaving section 103 21 c 22 c 23 c 24 and the fourth warp c from the fourth weaving section 104 25 c 26 c 27 c 28 At least one intersection between them. Preferably, the weft yarn column T, which is located in the main knitting section 105 and is closest to the first break 110 (i.e., the bottom 110a of the first break 110), is... 51 To T 57 It does not have a third warp c from the third weaving section 103 21 c 22 c 23 c 24 and the fourth warp c from the fourth weaving section 104 25 c 26 c 27 c 28 The intersection between them.

[0076] Preferably, such as Figure 4 As shown, with the fourth warp c 25 c 26 c 27 c 28 Each third warp c crosses 21 c 22 c 23 c 24 All with each fourth warp c 25 c 26 c 27 c 28 Cross once. Conversely, with the third warp c 21 c 22 c 23 c 24 Each fourth warp c crosses 25 c 26 c 27 c 28 All with each third warp c 21 c 22 c 23 c 24 Cross once.

[0077] Preferably, such as Figure 4 As shown, the third warp yarn c from the third weaving section 103 21 c 22 c 23 c 24 With the fourth warp c from the fourth weaving section 104 25 c 26 c 27 c 28 The crossing is carried out regularly in the second weft plane in the following manner: first, the warp yarns closest to the second break 120 are crossed, and then the warp yarns further and further away from the second break 120 are gradually crossed. Therefore, in the first weft yarn column T, which belongs to the second crossing region 105b and is closest to the second break 120... 61 In the middle, a single warp yarn c comes from the third warp yarn of the third part 103. 24 With the single fourth warp yarn c from the fourth weaving section 104 25 Crossover: The third warp c closest to the second break 120 24 The fourth warp c closest to the second break 120 25 Crossing. In the second weft yarn column T, which belongs to the second crossing region 105b and is closest to the second break 120,... 62 In the middle, only two of the third warp yarns c from the third part 103 are present. 24 c 23 With only two fourth warp yarns c from the fourth weaving section 104 25 c 26 Crossover: Third warp c 24 With the fourth warp c 26 Crossed, while the third warp c 23 With the fourth warp c 25 Crossing. In the third weft yarn row T, which belongs to the second crossing region 105b and is closest to the second break 120. 63 In the middle, only three of the third warp yarns c from the third part 103 are present. 24 c 23 c 22 With only three fourth warp yarns from the fourth weaving section 104 c 25 c 26 c 27 Crossover: Third warp c 24 With the fourth warp c 27 Cross, third warp c 23 With the fourth warp c 26 Crossed, while the third warp c 22 With the fourth warp c 25 cross.

[0078] Typically, T6n This represents the nth weft yarn column closest to the second break 120 in the main knitting section 105, where n is between 1 and N (inclusive), and N is the yarn column closest to the fourth yarn c in the second cross region 105b. 25 c 26 c 27 c 28 The third cross yarn c 21 c 22 c 23 c 24 The quantity or N is in the second cross region 105b with the third yarn c 21 c 22 c 23 c 24 The fourth cross yarn c 25 c 26 c 27 c 28 The quantity. In Figure 4 In the example shown, the quantity N is 4. Therefore, in each column T 6n In this process, n warp yarns from the third weaving section 103 intersect with n warp yarns from the fourth weaving section 104. Figure 4 In the example shown, for n=N, in the fourth column T 64 In the middle, there are 4 fourth warp yarns c from the fourth weaving section 104. 25 c 26 c 27 c 28 The four first warp yarns c from the third weave section 103 are crossed. 21 c 22 c 23 c 24 .

[0079] In addition, in each column T 6n In the middle, the third warp yarn c 2N-i With the fourth warp c 2N+n-i Cross, where i lies between 0 and n-1 (inclusive). Therefore, in Figure 4 In the example shown, in column T 62 In the middle, that is, n=2, the increment i=0 clearly indicates the third warp c 24-0 (i.e., c) 24 ) and the fourth warp c 24+2-0 (i.e., c) 26 The intersection and the increment i=1 clearly indicate the third warp c 24-1 (i.e., c) 23 ) and the fourth warp c 24+2-1 (i.e., c) 25 )cross.

[0080] Once the weft yarn T is reached 6N (exist Figure 4 The middle corresponds to column T 64 The number of yarn crossings in each weft row decreases regularly until the end of the second crossing region 105b, which is furthest from the second break 120. 6N+m This represents the (N+m)th weft yarn column in the main knitting section 105 closest to the second break 120, where m is between 1 and N-1 (inclusive), and N is the number of yarns in the second cross region 105b that intersects with the fourth yarn c. 25 c 26 c 27 c 28 The third cross yarn c 21 c 22 c 23 c 24 The quantity or N is in the second cross region 105b with the third yarn c 21 c 22 c 23 c 24 The fourth cross yarn c 25 c 26 c 27 c 28 The quantity. Therefore, in each column T 6N+m In the middle, Nm third warp yarns from the third weaving section intersect with Nm fourth warp yarns from the fourth weaving section. Figure 4 In the example shown, for m=2, in column T 66 In the middle, there are two fourth warp yarns c from the fourth weaving section 104. 27 c 28 The two third warp yarns c from the third weave section 103 cross each other. 21 c 22 .

[0081] Preferably, in the second weaving plane, the fourth warp yarn c from the second weaving section 102 has already been... 25 c 26 c 27 c 28 The third warp c from the third weave section 103 crosses over. 21 c 22 c 23 c 24 The weft yarns t2 of the second braided portion 102 of the fiber preform 100 are joined together, while the weft yarns t1 of the first braided portion 101 of the fiber preform 100 are not joined together, in order to restrict these already crossed third warp yarns c. 21 c 22 c 23 c 24The curvature. For the same reason, preferably, it has been combined with the third warp yarn c from the third weaving section 103. 21 c 22 c 23 c 24 The fourth warp c from the fourth weave section 104 crosses over. 25 c 26 c 27 c 28 The weft yarns t1 of the first braided portion 101 of the fiber preform 100 are joined together, while the weft yarns t2 of the second braided portion 102 of the fiber preform 100 are not joined together.

[0082] Preferably, the first plane and the second weaving plane are along the transverse direction D T The fiber preform 100 is regularly alternating to facilitate its movement along the transverse direction D. T The future shaping of the entire width. Of course, if the first plane and the second weave plane are along the lateral direction D T Irregular alternation is clearly not outside the scope of this invention. Preferably, in the lateral direction D... T In this configuration, one first knitting plane will not immediately follow another first knitting plane. Preferably, in the lateral direction D... T In this case, one second weave plane will not immediately follow another second weave plane.

[0083] Preferably, in the first braided section 101, the second braided section 102, the third braided section 103 and the fourth braided section 104, there is no cross between the warp yarns, so as to limit the curvature and tension in the fibers belonging to the fiber preform 100.

[0084] Preferably, the fiber preform 100 according to the invention does not include layer outlets, which means that the sum of the number of warp layers in the first portion 101 and the number of warp layers in the second braiding portion 102 corresponds to the number of warp layers in the main braiding portion 105, and corresponds to the sum of the number of warp layers in the third portion 103 and the fourth portion 104.

[0085] Preferably, the fiber preform 100 corresponds to a "dry" fibrous texture, i.e., not impregnated with resin or the like. The fiber preform 100 may comprise various types of multiple yarns, particularly ceramic or carbon fiber yarns or mixtures thereof. Preferably, the fiber preform 100 may be made of silicon carbide fibers. Typically, the fiber preform 100 may also be made from fibers made of materials such as alumina, mullite, silica, aluminosilicates, borosilicates, carbon, or mixtures of several of these materials.

[0086] like Figure 5As shown, the fiber preform 100 thus obtained is then shaped to obtain a fiber preform 10 by separating the first braided portion 101 and the second braided portion 102 by a first break portion 110, and separating the third braided portion 103 and the fourth braided portion 104 by a second break portion 120. This shaping operation is greatly simplified on the one hand by the warp crossings in the main braided portion 105 near the bottoms 110a and 120b of the break portions 110 and 120, and on the other hand by alternating the positions of the crossing regions 105a or 105b of the main braided portion 105 between the first braided plane and the second braided plane.

[0087] exist Figures 5 to 9 In the example shown, it is desirable to produce a π-shaped component 1, which includes a base 2, a first leg 3, and a second leg 4 extending from the base 2. Component 1 is preferably a turbine ring sector or an inter-blade platform. If it is desired to produce another composite component from the fiber preform according to the invention, this clearly does not depart from the scope of the invention.

[0088] Therefore, in order to form the fiber preform 30 of the first leg 3 (which forms the fiber reinforcement of the first leg 3), the first braided portion 101 of the fiber preform 100 is unfolded and arranged perpendicular to the second braided portion 102 and the main braided portion 105. In order to form the fiber preform 40 of the second leg 4 (which forms the fiber reinforcement of the second leg 4), the third braided portion 103 of the fiber preform 100 is unfolded and arranged perpendicular to the fourth braided portion 104 and the main braided portion 105. Finally, the fiber preform 20 of the base 2 is formed from the second braided portion 102, the fourth braided portion 104, and the main braided portion 105 of the fiber preform 100.

[0089] Therefore, as Figure 5 The fiber preform 10 shown 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.

[0090] 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 interval between the two leg preforms 30 and 40 substantially correspond to the length and width of the base 2 of the component 1 to be obtained, the lengths of the first leg 3 and the second leg 4, and the interval between the first leg 3 and the second leg 4, respectively. Figure 8 As shown schematically in the diagram.

[0091] Once the fiber preform 10 is obtained, the fiber preform 10 is densified by a matrix to obtain a component 1 comprising a fiber reinforcement made of the fiber preform 10.

[0092] Fiber preforms can be solidified or densified in a known gaseous manner via chemical vapor infiltration (CVI) of the matrix. A fiber preform, corresponding to a fiber-reinforced 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, as well as the composition of the gas phase, are selected to allow the gas phase to diffuse within the pores of the preform, forming at least a portion of the matrix by depositing a solid material at the core of the material in contact with the fibers, resulting from the decomposition of the gas phase components or the reaction between several components. This differs from the pressure and temperature conditions of CVD ("chemical vapor deposition") methods, which only result in surface deposition of the material. A SiC matrix can be formed using methyltrichlorosilane (MTS) through the decomposition of MTS to obtain SiC.

[0093] Densification can be achieved in a known manner by combining gas and liquid pathways to facilitate implementation and limit costs and manufacturing cycles, while obtaining satisfactory properties for the intended application. In this configuration, the consolidation of the fiber preform is carried out via gas as described above, followed by impregnation of the fiber preform with, for example, a suspension or slurry containing SiC particles and an organic binder (“slurry casting”), and then infiltration with liquid silica (“melt infiltration”). Densification can be performed in a known manner via resin injection molding or “resin transfer molding” (abbreviated as “RTM”) or via suspension injection molding or “slurry transfer molding” (abbreviated as “STM”). Figure 6 In the example shown, a fiber preform 10, previously gas-bonded or unbonded, is arranged in a cavity defined by a first portion 61 and a second portion 62 of a mold 60. The cavity has the shape of the part to be manufactured, which at least substantially has the shape of the part 1 to be manufactured.

[0094] 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 60 for injecting the slurry 6 includes a filter 63 at the outlet orifice of the slurry 6 in the mold 60, thereby allowing any matrix precursor particles to be retained in the mold 60, and in the case of the slurry, impregnating the fiber preform 10 as the matrix precursor particles are deposited in the mold 60.

[0095] Densification can also be achieved via membrane injection in a known manner, such as... Figure 7 As shown. This injection molding method allows for complete control over the amount of resin or slurry injected, thereby ensuring a precise and appropriate fiber volume ratio. Consequently, the mechanical properties of parts manufactured in this way are improved, and differences between parts are reduced.

[0096] A fiber preform 10 for forming the fiber reinforcement of component 1 is arranged in mold 70. Specifically, the fiber preform 10 can be arranged directly on the lower surface of impregnation chamber 71. This lower surface of impregnation chamber 71 may include a filter ( Figure 7 (Not shown in the image).

[0097] The mold 70 includes, on one hand, an impregnation chamber 71 in which the fiber preform 10 is disposed for densification by the matrix through the injection of impregnation fluid 8, and on the other hand, a compaction chamber 72 into which compressed fluid 9 is injected to apply pressure to the fiber preform 10 during matrix densification. 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, and the compressed fluid 9 applies pressure Q to the membrane 73, causing the membrane 73 to deform and thus apply pressure to the fiber preform 10.

[0098] Preferably, such as Figure 7 As shown, the membrane adheres to the surfaces of the leg preforms 30 and 40 of the fiber preform 10 and the base preform 20 located between the leg preforms 30 and 40, while the surface of the base preform 20 opposite to the leg preforms 30 and 40 abuts against one of the walls of the impregnation chamber 71 opposite to the membrane 73. The insert 74 can be used to facilitate the impregnation of the fiber preform 10 of the component 1. Figure 7 As shown, for example, resin can be injected into impregnation chamber 71 through inlet opening, and compressed fluid 9 can be injected into compaction chamber 72 through inlet opening.

[0099] Depending on the size, thickness, and shape of the part 1 to be manufactured, different injection sequences for compressing and impregnating fluids will be preferred.

[0100] A compressed fluid (such as water) is injected into the compaction chamber to apply pressure to the flexible membrane. This pressure, in turn, applies pressure to the fiber preform, allowing the impregnating fluid to penetrate the preform.

[0101] The preform is then heat-treated while maintaining the pressure applied by the membrane to form a matrix in the pores of the fiber preform.

[0102] When the densification step is completed, composite material part 1 is obtained, such as Figure 8 and Figure 9 As shown, its fiber reinforcement is composed of fiber preform 10, and its shape generally corresponds to the part 1 to be manufactured. Trimming or light machining steps can be performed on the manufactured part to obtain the part 1 to be manufactured. Furthermore, other components can be mounted or welded to the manufactured part to obtain the part 1 to be manufactured.

[0103] The obtained component can be made of ceramic matrix composite (CMC) or organic matrix composite (OMC). Preferably, the obtained composite component is made of SiC / SiC type ceramic matrix composite (CMC).

[0104] Figure 9 The diagram illustrates the fiber distribution in the matrix of a component obtained by the method of the present invention, where the fibers cross in region Z3 and do not cross in region Z4. Figure 9 As shown in region Z5, the fibers of the obtained component 1 well fill the angle between the base 2 and the first leg 3 and the second leg 4. (Similar to...) Figure 1 As shown, the improvement is significant compared to the parts obtained using existing methods.

[0105] The phrase “located between… and…” should be understood to include the endpoints.

Claims

1. A fiber preform (100), said fiber preform being passed through a longitudinal direction (D) L ) multiple warp yarns extending and along the transverse direction (D T The fiber preform (100) is produced in a single piece by three-dimensional weaving between multiple weft yarns extending from the warp yarns along the longitudinal direction (D). L The fiber preform (100) extends between the first longitudinal edge 100a and the second longitudinal edge 100b, comprising along the longitudinal direction (D). L At least one first break (110) extending from the first longitudinal edge (100a) of the fiber preform (100) and separating the first braided portion (101) and the second braided portion (102) in the fiber preform (100), the fiber preform (100) further including a main braided portion (105) without a break and along the longitudinal direction (D L The first braided portion (101) and the second braided portion (102) are located in the extensions of the second braided portion (102). The fiber preform (100) is characterized in that it has a first weaving plane and a second weaving plane different from the first weaving plane. In the first weaving plane, at least a portion of the warp yarns of the first weaving portion (101) and the second weaving portion (102) cross in the main weaving portion (105) in a first crossing region (105a) adjacent to the first break (110). In the second weaving plane, the warp yarns of the first weaving portion (101) and the second weaving portion (102) do not cross in the region adjacent to the first break (110), and the fiber preform (100) is oriented in the transverse direction (D). T It has alternating transformations between the first weaving plane and the second weaving plane.

2. The fiber preform (100) according to claim 1, wherein, In the first weaving plane, all the warp yarns of the first weaving portion (101) and the second weaving portion (102) cross in the main weaving portion (105).

3. The fiber preform (100) according to claim 1, wherein, In the first weaving plane, all the warp yarns of the first weaving portion (101) and the second weaving portion (102) cross at most once in the main weaving portion (105).

4. The fiber preform (100) according to claim 1, wherein, The first weaving plane includes a plurality of continuous weft yarn rows T in the main weaving section (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 column T 51 It is the weft yarn column adjacent to the first break (110), N corresponds to the number of warp yarns in the first weaving section (101) that intersect with the warp yarns of the second weaving section (102), so that in the weft yarn column T 5n In the process, the n warp yarns of the first weaving section (101) intersect with the n warp yarns of the second weaving section (102).

5. The fiber preform (100) according to claim 1, wherein the fiber preform (100) includes a second break (120) extending from the second longitudinal edge (100b) of the fiber preform (100) and separating a third braided portion (103) and a fourth braided portion (104) in the fiber preform (100), wherein the main braided portion (105) is located between the first braided portion (101) and the second braided portion (102), or between the third braided portion (103) and the fourth braided portion (104), wherein at least a portion of the warp yarns of the third braided portion and the fourth braided portion cross in the main braided portion (105) in a second crossing region (105b) adjacent to the second break (120) in the second braided plane.

6. The fiber preform (100) according to claim 5, wherein, The second weaving plane includes multiple consecutive weft yarn rows T in the main weaving section (105). 6n (T) 61 ,T 62 ,T 63 ,T 64 ,T 65 ,T 66 ,T 67 ), where n is between 1 and N, and the weft yarn column T 61 It is the weft yarn column adjacent to the second break (120), N corresponds to the number of warp yarns in the third knitting section (103) that intersect with the warp yarns of the fourth knitting section (104), so that in the weft yarn column T 6n In the process, the n warp yarns of the third weaving section (103) intersect with the n warp yarns of the fourth weaving section (104).

7. The fiber preform (100) according to claim 5, wherein, The fiber preform (100) is used to form the fiber reinforcement of the π-shaped turbine ring sector.

8. The fiber preform (100) according to claim 1, wherein, In the first weaving plane, each warp of the first weaving portion (101) that intersects with the warp of the second weaving portion (102) intersects with all the warp of the second weaving portion (102) that intersect with the warp of the first weaving portion (101).

9. The fiber preform (100) according to claim 1, wherein, In the first weaving plane, each warp yarn of the first weaving section (101) intersects with all the warp yarns of the second weaving section (102).

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

11. A method for manufacturing a composite material component (1), said method Includes the following steps: The method for manufacturing fiber preforms according to claim 10 produces fiber preforms (10), and The fiber preform (10) is densified by a matrix to obtain the composite material component (1).

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

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