Reinforcing fibrous texture for a composite material part

Abstract

A reinforcing fibrous texture for a composite material part. A reinforcing fibrous texture (20) for a composite material part comprises a three-dimensional or multilayer weave between layers of warp yarns (C1-C10) juxtaposed within the thickness of the fibrous texture and layers of weft yarns (T1-T10) juxtaposed within the thickness of the fibrous texture. The fibrous texture has a specific weave structure on a plurality of warp planes (CH1, CH2) and on a plurality of weft planes. The weave structure has a single weave infiltration score greater than or equal to 0.67 and a number of contact points less than 70. Figure for the abstract: Fig. 5A and 5B.

Description

Title of the invention: Reinforcing fibrous texture for a composite material part. Technical field

[0001] The invention relates to fibrous textures comprising a three-dimensional or multilayer weave used to form fibrous reinforcements in composite materials. Prior art

[0002] One application of the invention is the production of parts made of structural composite material, that is, structural parts reinforced with fibers and densified by a matrix. Composite materials make it possible to produce parts with a lower overall mass than the same parts when made of metallic material.

[0003] The invention relates more particularly to composite material parts manufactured from a fibrous reinforcement obtained at least in part by three-dimensional (3D) or multilayer weaving between a plurality of warp yarn layers and a plurality of weft yarn layers, the reinforcement being densified by chemical infiltration in the gas phase (CVI). A 3D weave may, for example, correspond to an interlock weave, while a multilayer weave may, for example, correspond to a multi-plain, multi-satin, or multi-twill weave.

[0004] Depending on the 3D or multilayer weave structure used to form the fibrous texture, the latter exhibits varying degrees of infiltration, that is, a greater or lesser capacity for the reactive gas used for CVI to penetrate the fiber. Infiltration depends in particular on the density of warp yarns passing through two or more weft layers within the thickness of the fibrous texture. Indeed, when a warp yarn connects two or more weft yarns, it creates a preferential path that facilitates the flow of gas within the fibrous texture.

[0005] Furthermore, in the case of a weave structure comprising a two-dimensional woven skin on the surface of a 3D or multilayer weave, the skin creates a densification gradient between the surface and the core of the fibrous texture with a faster densification on the surface which then blocks the surface porosity and prevents good densification at the core of the fibrous texture.

[0006] Furthermore, the number of contact points between the warp and weft yarns in a 3D or multilayer weave influences the deformability and bulk of a fibrous texture. A texture with a weave structure with many contact points is not very deformable and has little bulk, which poses problem during shaping in former, the preform does not completely fill the former's air gap.

[0007] Consequently, there is a need to define fibrous textures formed at least in part by three-dimensional or multilayer weaving that offer a good compromise between infiltration and deformation and expansion capacity. Description of the invention

[0008] To this end, the invention proposes a reinforcing fibrous texture for a part made of composite material, the fibrous texture having a three-dimensional or multi-layered weave between layers of warp yarns juxtaposed in the thickness of the fibrous texture and layers of weft yarns juxtaposed in the thickness of the fibrous texture, the fibrous texture further comprising on one of its external surfaces a skin having a two-dimensional weave and covering the three-dimensional or multi-layered weave, the fibrous texture having a weave structure determined on a plurality of warp planes and on a plurality of weft planes, characterized in that the weave structure has a complex weave infiltration score greater than or equal to 0.67 and a number of contact points less than 70,The complex weave infiltration score of the fibrous texture corresponds to the ratio between a number of actual crossing points of interest between warp and weft yarns of the skin of the fibrous texture and a maximum number of theoretical crossing points on said skin, each actual crossing point of interest corresponding to a change in relative position in the direction of the thickness of the fibrous texture of a warp yarn of the skin relative to a weft yarn between two successive warp planes, said warp yarn of the skin being located above a warp yarn of a layer of warp yarns underlying the warp yarn layer of the skin linking at least two layers of weft yarns in the thickness of the fibrous texture,the number of contact points corresponding to the sum of warp contact point values ​​per centimeter determined for each warp contact point and weft contact point values ​​per centimeter determined for each weft contact point, a warp contact point, respectively a weft contact point, corresponding to a change in relative position in the thickness direction of the fibrous texture of a warp yarn, respectively a weft yarn, in a warp plane, respectively in a weft plane, of the weave structure of the fibrous texture. ,

[0009] The fibrous texture according to the invention, comprising on the surface a 2D skin and at its core a 3D or multilayer woven structure, thus presents a good compromise between:

[0010] - infiltrability, that is to say the capacity of the fibrous texture to infiltrate the gas A reagent used for CVI, which improves core CVI densification, and

[0011] - capacity for deformation and expansion in order to facilitate the shaping of the fibrous texture.

[0012] According to a particular aspect of the fibrous texture of the invention, the complex armor infiltration score Sm corresponds to the following formula: ç - pcl^ptr , telqueP^iJ)^

[0013] where Pch is the number of warp planes, PTr is the number of frame planes, / z is a function for identifying real crossing points of interest, i is the current warp plane, j is the current frame plane

[0014] According to another particular aspect of the fibrous texture of the invention, the number of contact points N corresponds to the following formula: N = Nch xC x +Ntr x D x \PtrxCch) IPchxCtr)

[0015] With: N: Total number of contact points

[0016] Nch: Number of contact points in the chain per plane (counted according to the principle above)

[0017] Ntr: Number of contact points in the Frame per plane (counted according to the principle above)

[0018] C = Count (number of warp threads per cm)

[0019] D = Weft thread count (Number of weft threads per cm)

[0020] Pch = Number of shots in Chain Ptr = Number of Frame planes Cch = Number of Channel layers Ctr = Number of frame layers.

[0021] The invention also relates to a reinforcing fibrous texture for a composite material part, the fibrous texture comprising a three-dimensional or multi-layered weave between layers of warp yarns juxtaposed within the thickness of the fibrous texture and layers of weft yarns juxtaposed within the thickness of the fibrous texture, the three-dimensional or multi-layered weave being present on external surfaces of the fibrous texture, the fibrous texture having a specific weave structure on a plurality of warp planes and on a plurality of weft planes, characterized in that the weave structure has a simple weave infiltration score greater than or equal to 0.67 and a number of contact points less than 70, the simple weave infiltration score of the fibrous texture corresponding to the ratio between a number of actual crossing points between warp yarns of the layer of warp yarn present on an external surface of the fibrous texture and weft yarns of layers of weft yarns and a maximum number of theoretical crossing points on the external surface of the fibrous texture, each actual crossing point corresponding to a change in relative position in the direction of the thickness of the fibrous texture of a warp yarn with respect to a weft yarn between two successive warp planes, the number of contact points corresponding to the sum of warp contact point values ​​per centimeter determined for each warp contact point and weft contact point values ​​per centimeter determined for each weft contact point, a warp contact point, respectively a weft contact point, corresponding to a change in relative position in the direction of the thickness of the fibrous texture of a warp yarn, respectively of a weft yarn, in a warp plane,respectively in a weft plane, of the weave structure of the fibrous texture.

[0022] The fibrous texture according to the invention, formed by a 3D or multilayer weave, thus presents a good compromise between:

[0023] - infiltrability, that is to say the ability of the fibrous texture to infiltrate the gas reagent used for CVI, which improves core CVI densification, and

[0024] - deformation and bulking capacity to facilitate shaping of the fibrous texture.

[0025] According to a particular aspect of the fibrous texture of the invention, the simple armor infiltration score Si corresponds to the following formula: Ai- pc^ptr

[0026] where Pa is the number of chain plans P Tr is the number of frame planes / is a function for identifying real intersection points i is the current chain plan j is the current frame plan

[0027] According to another particular aspect of the fibrous texture of the invention, the number of contact points N corresponds to the following formula: N = Nch x C x (ptr x Cch^ + Ntr x D x ^pch x ctr^

[0028] With: N: Total number of contact points

[0029] Nch: Number of contact points in the chain per plane (counted according to the principle above)

[0030] Ntr: Number of contact points in the Frame per plane (counted according to the principle above)

[0031] C = Count (number of warp threads per cm)

[0032] D = Weft thread count (Number of weft threads per cm)

[0033] Pch = Number of shots in Chain

[0034] Ptr = Number of frames in frame

[0035] Cch = Number of Chain Layers Ctr = Number of frame layers.

[0036] The invention also relates to a composite material part having a reinforcing fibrous texture according to the invention, densified by a matrix at least partially formed by chemical vapor deposition. The reinforcing fibrous texture may, in particular, comprise ceramic or carbon fibers. Brief description of the drawings

[0037] [Fig. 1A-1R] Figures IA to IR illustrate successive planes of a woven fabric of fibrous texture with three-dimensional core weave and two-dimensional skin weave,

[0038] [Fig.2] Fig.2 illustrates a grid of one of the external surfaces of a texture fibrous material having the weave structure of figures IA to IR used for calculating an infiltration score according to the invention,

[0039] [Fig.3] Fig.3 illustrates four theoretical intersection points of a cell of the grid of Fig.2

[0040] [Fig.4] Figure 4 illustrates an example of assigning values ​​to contact points in a 3D woven fibrous texture according to the invention,

[0041] [Fig. 5A-5F] Figures 5A to 5F illustrate successive planes of a woven fabric with a fibrous texture and three-dimensional weave according to an embodiment of the invention,

[0042] [Fig. 6A-6L] Figures 6A to 6L illustrate successive planes of a woven fabric with a fibrous texture, featuring a three-dimensional core weave and a two-dimensional skin weave, according to one embodiment of the invention.

[0043] [Fig. 7A-7H] Figures 7A to 5H illustrate successive planes of a weaving armor of a fibrous texture with three-dimensional weaving according to an embodiment of the invention. Description of the implementation methods

[0044] The invention relates to the definition of fibrous textures having a three-dimensional (3D) or multilayer weave structure between a plurality of warp yarn layers and a plurality of weft yarn layers, intended to form a fibrous reinforcement for a composite material part, the fibrous texture being at least partially consolidated or densified by chemical infiltration in gaseous mode (CVI). The fibrous texture is intended to form the fibrous reinforcement of a composite material part. composite, in particular but not exclusively, a part made of ceramic matrix composite (CMC) material, that is to say, comprising a fibrous reinforcement, for example, of carbon or ceramic fibers densified by a matrix at least partially made of ceramic.

[0045] By "three-dimensional weaving" or "3D weaving", we mean here a weaving method in which at least some of the warp yarns link weft yarns over several weft layers such as for example an "interlock weave" in which each warp layer links several weft layers with all the yarns in the same warp column having the same movement in the plane of the weave.

[0046] The term "multilayer weave" here refers to a 3D weave with several weft layers, the basic weave of each layer being equivalent to a conventional 2D fabric weave, such as plain weave, satin weave, or twill weave, but with certain points of the weave that bind the weft layers together. Known examples of multilayer weave weaves are multiplain weave, multisatin weave, and multitwill weave.

[0047] A 3D or multilayer weave structure defines how the warp yarns interlace with the weft yarns and vice versa, according to an elementary pattern for each plane of the weave structure. The weave pattern is defined on a plurality of warp cross-section planes, also called warp planes, which show the path of the warp yarns relative to the weft yarns (represented in cross-section) through the thickness of a fibrous texture for a given column of warp yarns, i.e., the path of one warp yarn for each layer of warp yarns, as well as on a plurality of weft cross-section planes, also called weft planes, which show the path of the weft yarns relative to the warp yarns (represented in cross-section) through the thickness of a fibrous texture for a given column of weft yarns, i.e., the path of one weft yarn for each layer of weft yarns.The warp and weft planes are repeated in order throughout the weaving of the fibrous texture. Figure 2 shows an example of a multilayer weave whose representative pattern is defined on eight warp planes.

[0048] CVI treatment is a well-known process for densifying porous preforms to produce parts made of CMC composite material. The preform(s) to be densified are placed in a reaction chamber of a CVI installation where they are heated. A reactive gas containing one or more gaseous precursors of the matrix material is introduced into the reaction chamber. The temperature and pressure in the installation are adjusted to allow the reactive gas to diffuse within the porosity of the preforms and form a deposit of the matrix material by decomposition of one or more components of the reactive gas or by reaction between several components, these components forming the matrix precursor. Such a process is described, in particular, in US patent 9,845,534.

[0049] According to the invention, a weave of a fibrous texture having a good compromise between infiltration and deformation and bulking capacity has an infiltration score of simple or complex weave greater than or equal to 0.67 and a number of contact points less than 80, more preferably less than 70.

[0050] Calculating an infiltration score for a fibrous texture allows for the determination of a representative value of its potential for infiltration by the gas(s) used for CVI. As described in detail below, a "simple weave infiltration score" allows for the determination of a representative value of the infiltration potential of a 3D or multilayer weave when it is present on the external surfaces of the fibrous texture, i.e., directly accessible to the reactive gas of the CVI. A "complex weave infiltration score" allows for the determination of a representative value of the infiltration potential of a weave comprising an inner part or core formed by a 3D or multilayer weave and an outer part or skin having a two-dimensional weave and covering the 3D or multilayer weave.

[0051] As explained below, the "simple weave infiltration score" corresponds to the ratio between a number of actual crossing points between warp yarns of the warp yarn layer present on an external surface of the fibrous texture and weft yarns of weft yarn layers and a maximum number of theoretical crossing points on the external surface of the fibrous texture, while the "complex weave infiltration score" corresponds to the ratio between a number of actual crossing points near an underlying deep bond, called "crossing points of interest", between warp yarns and weft yarns of the skin of the fibrous texture and a maximum number of theoretical crossing points on said skin.

[0052] An example of calculating an infiltration score for a fibrous texture illustrated in Figures IA to IR is now described. Figures IA to IR represent eighteen successive warp planes CH1 to CH18 of a weave structure of a fibrous texture 10 obtained by 3D core weaving 12 and two-dimensional skin weaving 14, 16. The representative pattern of the weave of the fibrous texture 10 is defined on eighteen warp and weft planes. The fibrous structure 10 comprises five layers of warp yarns Ci to C5 and five layers of weft yarns Ti to T5.

[0053] The calculation of the infiltration score begins by dividing one of the external surfaces of the fibrous texture 10, here the surface of the fibrous texture 10 comprising the skin 16, into a plurality of square cells as shown in [Fig. 2]. Each square cell corresponds to an intersection between a warp plane CH1 to CH18 and a weft plane TRI to TRI8. The square cells of the grid represent the behavior of the warp yarn Cii to Ci18 of the warp yarn layer Ci of the skin 16 respectively on the eighteen warp planes CH1 to CH18 and weft planes TRI to TR18. For example, the warp yarn Cn visible on the warp plane CH1 of [Fig. 1A] is represented in [Fig. 2] in the left column from bottom to top of the figure, and so on for warp yarns Ci2 to Ci18 from left to right in [Fig. 2]. The black squares represent warp yarns visible on the surface of the fibrous texture, while the white squares represent weft yarns visible on the surface of the fibrous texture.

[0054] In the following explanation of the calculation of the infiltration score, we generalize by denoting PCh as the number of warp planes, and Ptr as the number of weft planes. We also denote Cch as the number of warp layers, and Ctr as the number of weft layers. In the example in Figures IA to IR, Cch = Ctr.

[0055] Noting ' the current warp plane, and j the current weft plane, and y)the position of warp thread k, defined by the number of frames locally above the thread k (wire 1 being the surface wire), the value of cell c(i, j) is obtained by the formula next: C (iJ) = for 1 < i < PCh and for 1 < i < PTr

[0056] The cells in black in figure 2 therefore correspond to the cells (i, j) for which C (i, j) = 0, and the cells in white therefore correspond to the cells (i-, j) for which C (i. j) = 1.

[0057] For example, the value of cells C(i, j) in the left column on [Fig.2] of From bottom to top, C(l,l) = 1 (weft yarn above warp yarn Cn), C(l,2) = 1 (thread C(l, 3) = 1 (weft yarn above warp yarn Cn), C(l, 4) = 0 (weft yarn below warp yarn Cn), C(l, 5) = 0 (weft yarn below warp yarn Cn), C(l, 6) = 0 (weft yarn below warp yarn Cn), C(l, 7) = 1 (weft yarn above warp yarn Cn), C(l, 8) = 1 (weft yarn above warp yarn Cn), C(l, 9) = 1 (weft yarn above warp yarn Cn), C(l, 10) = 0 (weft yarn below warp yarn Cn), C(l, 11) = 0 (weft yarn below warp yarn Cn), C(l, 12) = 0 (weft yarn below warp yarn Cn) of warp yarn Cn2), C(l, 13) = 1 (weft yarn above warp yarn Ci n), C(l, 14) = 1 (weft yarn above warp yarn Ci i4), C(l, 15) = 1 (weft yarn above warp yarn Ci i5), C(l, 16) = 0 (weft yarn below warp yarn Ci i6), C(l, 17) = 0 (weft yarn below warp yarn Ci i7) C(l,18) = 0 (weft yarn below warp yarn Ci [8). ,

[0058] Each square cell has four vertices, each corresponding to a theoretical crossing point between a warp yarn and a weft yarn.

[0059] Figure 3 illustrates the four theoretical intersection points of a square cell C(i, j). For a given cell C(i, j), the theoretical intersection points between A warp thread and a weft thread are identified at the vertices of the square cells. as indicated below, with the following boundary assumptions:

[0060] Point [-j, j +j) = Point (Pch + j, j+j), pourl <j<Ptr Point j-j) = Point (Pch + j, j-j), pour \<j<Ptr Point (i + ^, -^) = Point (i + j, Ptr+j), forl <i<PCh Point (i-^, -5) = Point (i-j Ptr+^), pour\<i<PCh Cell (-1, j) = Cell (PCh, j), for 1 < j <Ptr Cell (i, -1) = Cell (i, Ptr), for 0 < i < PCh

[0061] It is thus possible to determine the maximum number of theoretical crossing points on the external surface of the fibrous texture.

[0062] The function f defined below allows us to isolate the actual crossing points, represented by Pi and P2 in Figure 2, from among all the theoretical crossing points on a given cell (i, j):

[0063] For 1 < i < PCh -1 and 1 < j < PTr 100641 rti 1 = J \l~2'J ~ 2 ) ~ J \l+2'J ~ 2 ) ~ \ „ . l 0 otherwise

[0065] The actual warp and frame crossing points are those for which the function f equals 1.

[0066] Each actual crossing point corresponds to a change in relative position in the direction of the thickness of the fibrous texture of a warp yarn with respect to a weft yarn between two successive warp planes

[0067] In the case of a 3D or multilayer weave armor present directly on the external surfaces of the fibrous texture, i.e. without a two-dimensional skin on its surface, all the real isolated crossing points on the surface of the fibrous texture are added together as described above, and then the number of real crossing points found is divided by the maximum number of theoretical crossing points on the external surface of the fibrous texture to calculate a simple armor infiltration score.

[0068] The "simple armor" infiltration score, denoted Sq, can be calculated using the following formula:

[0069] '

[0070] where P a is the number of chain plans P Tr is the number of frame planes / is a function for identifying real crossing points i is the current chain plane j is the current frame plan

[0071] By way of example, if we consider that [Fig.2] represents the surface of a fibrous texture without the two-dimensional skin, namely that the warp yarns present in the first layer of warp yarns already make deep bonds, the simple infiltration score would be 216 / 324 = 0.67.

[0072] In the case of a weave comprising an inner part or core formed by a 3D or multilayer weave and an outer part or skin having a two-dimensional weave and covering the 3D or multilayer weave, as shown in Figures IA to IR and 2, the cells where a deep bonding point exists are first identified. A deep bonding point corresponds to a warp yarn from a layer of warp yarns underlying the warp yarn layer of the skin that binds at least two layers of weft yarns within the thickness of the fibrous texture. The cells where a deep bonding point exists are represented with a point Lpa or Lpd in [Fig. 2], Lpa corresponding to an upward deep bonding point and Lpd corresponding to a downward deep bonding point.To do this, simply look at the behavior of the warp yarn C2i to C21 8 (figures IA to IR), warp plane by warp plane, and identify the positions where two or more weft layers are linked.

[0073] The cells (i, j) for which there is a depth link point are identified by the values ​​+1 or -1 in the output of the following function:

[0074] 0" l <P2(i,j) <2' isip2(i,.n>2 -Isi P2(i, j) <1 ,

[0075] Cells (i, j) for which g(L j ) = 1 are identified by a point Lpd (downward linkage) (Figure 2). Cells (i, j) for which g(i, j) = -1 are identified by a point Lpa (upward linkage) ([Fig.2]).

[0076] Once this identification has been carried out, the function defined below makes it possible to distinguish, among the real crossing points, the real crossing points of interest represented by Pi on the [Fig.2].

[0077] For the <i<PC / » et 1< j <PTrh xmin( J)\ + \g(i-U j) ] + \g(ù j-1 ) | + |#(i- IJ-1)|, 1)

[0078] The actual crossing points of interest are those that are close to a deep binding of a warp yarn in the fibrous texture. In other words, each actual crossing point of interest Pi corresponds to a change in relative position in the thickness direction of the fibrous texture of a skin warp yarn with respect to a weft yarn between two successive warp planes, the considered skin warp yarn being located above a warp yarn of a layer of warp yarns underlying it. the warp yarn layer of the skin binding at least two layers of weft yarns within the thickness of the fibrous texture

[0079] The actual crossing points of interest between the warp and weft yarns of the skin are those for which the function h equals 1 (h=0 for the others). This can be determined by examining the four cells adjacent to each of these points.

[0080] The "multilayer infiltration" score, denoted Sm, can be calculated using the formula next: , if 3 (i, j) such that P}(i, j) otherwise

[0081] where P ch is the number of chain planes P Tr is the number of frame planes h is a function for identifying real crossing points of interest, i is the current warp plane, j is the current frame plane

[0082] The infiltration score of the weave structure shown in Figures IA to IR is 0.22, obtained on the basis of the number of Pi points present in [Fig. 2] divided by the maximum number of theoretical crossing points on the external surface of the fibrous texture, i.e., 72 / 324. The fibrous texture having the weave structure defined in Figures IA to IR has an unsatisfactory infiltration score because it is less than 0.67.

[0083] Calculating the number of contact points between warp and weft yarns allows us to evaluate the deformation (flexibility) and bulking capacity of a fibrous texture.

[0084] The calculation of the number of contact points for the warp yarns of the fibrous texture begins by calculating, for each warp yarn in the warp yarn layers of the fibrous texture, a warp contact point value. A contact point corresponds to a change in relative position in the direction of the thickness of the fibrous texture of a warp yarn in a warp plane of the weave of the fibrous texture. The value of a warp contact point is determined based on the number of weft yarn layers traversed by a given warp yarn corresponding to a depth of the bonding point in the weft yarn layer(s), the calculation being repeated for each warp weave plane. As illustrated in the example in [Fig. 4], the warp yarn Ca has two contact points. A value of 1 is assigned to the first contact point of the warp yarn Ca on the left in [Fig. 4].4] since the warp yarn Ca passes through a layer of weft yarns Ta here. A value of 2 is assigned to the second point of contact of the warp yarn Ca on the right in [Fig. 4] since the warp yarn Ca passes through two layers of weft yarns Ta and Tb here. Similarly, the warp yarn Cb has two points of contact to which a value of is assigned. A value of 1 is assigned to the first point of contact of the warp yarn Cb on the left in [Fig. 4] since the yarn Cb passes through one layer of weft yarns Tb, and a value of 2 is assigned to the second point of contact of the warp yarn Cb on the right in [Fig. 4] since the yarn Cb passes through two layers of weft yarns Tb and Te. The warp yarn Ca has two points of contact. A value of 1 is assigned to each of the two points of contact of the warp yarn Ce since the yarn Ce passes through a single layer of weft yarns Te twice.

[0085] More generally, when a warp yarn passes through n layers of weft yarns, this corresponds to a point of contact to which the value n is assigned.

[0086] A value is assigned to all identified contact points for warp yarns of all warp yarn layers, i.e. for each warp yarn present in each warp plane of the weave of the fibrous texture.

[0087] The calculation of the number of contact points then involves calculating a value for warp contact points per centimeter. For this purpose, the weft yarn count, corresponding to the number of weft yarns per centimeter, also called "weft count per centimeter," is calculated to obtain a figure for the number of contact points per centimeter. To manage the weft counts, an average contact weighting is calculated for a layer and multiplied by the number of yarns per cm in each direction.

[0088] The steps described above are also carried out for the weft yarns of the fibrous texture, namely:

[0089] - Calculation for each weft yarn of the weft yarn layers of the fibrous texture of a value of contact points in the weft (a contact point corresponds to a change in relative position in the direction of the thickness of the fibrous texture of a weft yarn in a weft plane of the weave of the fibrous texture) according to the method described above for warp yarns,

[0090] - calculation of a value of contact points in the grid per centimeter, the texture of the warp threads, corresponding to the number of warp threads per centimeter also called "count per centimeter", in order to obtain a figure of the number of contact points per centimeter.

[0091] The warp and weft contact point values ​​per centimeter previously calculated are then added together to obtain a number of contact points in the fibrous texture.

[0092] The calculation of the number of contact points in a fibrous texture can be obtained using the following formula:

[0093] , y = Nch xcx (PtrxCcfl) +^trxDx ipchxCtr)

[0094] With:

[0095] N: Total number of contact points

[0096] Nch: Number of contact points in the chain per plane (counted according to the principle above)

[0097] Ntr: Number of contact points in the Frame per plane (counted according to the principle above)

[0098] C = Count (number of warp threads per cm)

[0099] D = Weft thread count (Number of weft threads per cm)

[0100] P ch = Number of shots in Chain

[0101] Ptr = Number of frames in frame

[0102] Cch = Number of Chain Layers

[0103] Ctr = Number of frame layers

[0104] Based on this calculation formula, it is therefore possible to count the number of contact points on new armors, and thus to estimate their behavior in terms of bulking and deformability relative to each other.

[0105] The number of contact points calculated for the fibrous texture having the weave structure defined in figures IA to IR is 65, which is satisfactory because it is less than 80.

[0106] Thus, the weave structure defined in figures IA to IR is not retained to produce a fibrous texture according to the invention because of an infiltrability score of less than 0.67 which does not allow to ensure good chemical infiltration in gas phase at core resulting in excessively large matrix deposition gradients between the external surface and the core of the texture.

[0107] The table below presents the infiltration scores and the number of contact points calculated according to the methods detailed above for known 3D interlock armor, with and without 2D skin, and known multilayer multi-canvas, multi-satin and multi-twill armor: Armor Type | Infiltration Score | Number of Contact Points | Multi-fabric 0.4 (Sm) 152 | Multi-satin 0.19 (Sm) 34 | Interlock 0.5 (S) 90 | Interlock + surface skin 0.25 (Sm) 90 | Multi-twill 0.67 (Sm) 115

[0108] It is observed that each of the known armors listed above has at least an infiltration score of less than 0.67 or a number of contact points greater than 80. In other words, none of the known 3D or multi-layered armors satisfies the compromise between infiltration and deformation and expansion capacity defined by the present invention.

[0109] Examples of weaving reinforcements for fibrous textures of composite material parts are now presented which satisfy the compromise between infiltration and deformation and bulking capacity defined by the present invention, namely reinforcements having an infiltration score greater than or equal to 0.67 and a number of contact points less than 80, more preferably less than 70.

[0110] Figures 5A to 5F represent six successive warp planes CH1 to CH6 of a woven fibrous texture 20 obtained by three-dimensional weaving, present on external surfaces 20a and 20b of the fibrous texture. The representative pattern of the weave of the fibrous texture 10 is defined on six warp and weft planes. The fibrous structure 20 comprises ten layers of warp yarns Ci to C10 and ten layers of weft yarns Ti to Ti0.

[0111] The weave structure defined in Figures 5A to 5F consists of a 3D weave present directly on the external surfaces of the fibrous texture, i.e., with, for example, the warp yarns Cn to Ci6 of the first layer of warp yarns Ci which already bind at least two layers of weft yarns to the external surface 20a of the fibrous texture 20. As explained above, the infiltration score of the fibrous texture 20 therefore corresponds to the simple weave infiltration score calculated with the following formula: [0H2] ' $1 - PchxPtr

[0113] The fibrous texture 20 has an infiltration score of 0.67, which is equivalent to the infiltration score of a multi-twill armor. However, the fibrous texture 20 has a contact point count of 63, which is significantly lower than the 115 contact points of the multi-twill armor and, more importantly, lower than the maximum contact point count of 80 defined in the present invention.

[0114] Figures 6A to 6L represent twelve successive warp planes CH1 to CH12 of a woven structure of a fibrous texture 30 obtained by 3D core weaving 32 and two-dimensional skin weaving 34, 36. The representative pattern of the weave of the fibrous texture 30 is defined on twelve warp and weft planes. The fibrous structure 30 comprises ten layers of warp yarns Ci to C10 and ten layers of weft yarns Ti to Ti0

[0115] As explained above, the infiltration score of the fibrous texture 30 therefore corresponds to the multilayer infiltration score Sm calculated with the following formula: [0H6] , Sm = , if 3 (i, j) such that P^iJ) >2, [Sl otherwise

[0117] The fibrous texture 30 has an infiltration score of 0.33 and a number of contact points equal to 77. The weave structure of the fibrous texture 30 therefore meets the conditions to offer a good compromise according to the invention between infiltration and deformation and expansion capacity.

[0118] Figures 7A to 7H represent eight successive warp planes CH1 to CH8 of a weave structure of a fibrous texture 40 obtained by three-dimensional weaving, present on external surfaces 40a and 40b of the fibrous texture. The representative pattern of the weave of the fibrous texture 40 is defined on eight warp and weft planes. The fibrous structure 40 comprises ten layers of warp yarns Ci to C10 and eleven layers of weft yarns Ti to Tib

[0119] The weave structure defined in Figures 7A to 7H consists of a 3D weave present directly on the external surfaces of the fibrous texture, i.e., with, for example, the warp yarns Cn to Ci8 of the first layer of warp yarns Ci which already bind at least two layers of weft yarns to the external surface 40a of the fibrous texture 40. As explained above, the infiltration score of the fibrous texture 40 therefore corresponds to the simple weave infiltration score calculated with the following formula:

[0120] $1 “Pc^tr

[0121] The fibrous texture 40 has an infiltration score of 0.5. Furthermore, the fibrous texture 40 has a number of contact points less than 80, corresponding to the maximum number of contact points defined in the present invention. The weave structure of the fibrous texture 40 therefore meets the conditions for offering a good compromise according to the invention between infiltration and deformation and bulking capacity.

[0122] The chemical nature of the fibers is chosen according to the intended application. Thus, in the case of a part made of thermostructural composite material reinforced with refractory fibers, a fibrous structure with carbon fibers and / or ceramic fibers, for example silicon carbide (SiC), can be used, the fibrous texture being densified by a matrix at least partially formed by chemical vapor phase infiltration.

Claims

Demands

1. A fibrous reinforcement texture (30) for a composite material part, the fibrous texture having a three-dimensional or multilayer weave (32) between layers of warp yarns (Ci, Cio) juxtaposed in the thickness of the fibrous texture and layers of weft yarns (TrT10) juxtaposed in the thickness of the fibrous texture (30), the fibrous texture further comprising on one of its external surfaces a skin (36) having a two-dimensional weave and covering the three-dimensional or multilayer weave, the fibrous texture having a weave structure determined on a plurality of warp planes (CH1-CH12) and on a plurality of weft planes, characterized in that the weave structure has a complex weave infiltration score greater than or equal to 0.67 and a number of contact points less than 70,the complex weave infiltrability score of the fibrous texture corresponding to the ratio between a number of actual crossing points of interest (Pi) between warp and weft yarns of the skin (36) of the fibrous texture (30) and a maximum number of theoretical crossing points on said skin, each actual crossing point of interest (PJ) corresponding to a change in relative position in the direction of the thickness of the fibrous texture of a warp yarn of the skin relative to a weft yarn between two successive warp planes, said warp yarn of the skin being located above a warp yarn of a layer of warp yarns underlying the warp yarn layer of the skin linking at least two layers of weft yarns in the thickness of the fibrous texture,the number of contact points corresponding to the sum of warp contact point values ​​per centimeter determined for each warp contact point and weft contact point values ​​per centimeter determined for each weft contact point, a warp contact point, respectively a weft contact point, corresponding to a change in relative position in the thickness direction of the fibrous texture of a warp yarn, respectively a weft yarn, in a warp plane, respectively in a weft plane, of the weave structure of the fibrous texture.

2. Texture according to claim 1, wherein the complex armor infiltration score Sm corresponds to the following formula: ^n- P(^ptr , such that P^iJ)>2' where P ch is the number of warp planes, P Tr is the number of frame planes, h is a function identifying real crossing points of interest, i is the current warp plane, and j is the current frame plane

3. Texture according to claim 1 or 2, wherein the number of contact points N corresponds to the following formula: N - Nch x C x + Ntr x D x (p, > \Ptr x Cch) [Pch x Ctr) Where: N: Total number of contact points Nch: Number of warp contact points per plane Ntr: Number of weft contact points per plane C = Count (number of warp threads per cm) D = Weft (number of weft threads per cm) Pch = Number of warp planes Ptr = Number of weft planes Cch = Number of warp layers Ctr = Number of weft layers

4. A fibrous reinforcement texture (20) for a composite material part, the fibrous texture comprising a three-dimensional or multilayer weave between layers of warp yarns (Ci-Ci0) juxtaposed in the thickness of the fibrous texture and layers of weft yarns (TrTio) juxtaposed in the thickness of the fibrous texture, the three-dimensional or multilayer weave being present on external surfaces (20a, 20b) of the fibrous texture (20), the fibrous texture having a determined weave structure on a plurality of warp planes (CHrCH6) and on a plurality of weft planes, characterized in that the weave structure has a single weave infiltration score greater than or equal to 0.67 and a number of contact points less than 70,the simple weave infiltration score of the fibrous texture corresponding to the ratio between a number of actual crossing points (Pb P2) between warp yarns of the warp yarn layer present on an external surface (20a) of the fibrous texture (20) and weft yarns of weft yarn layers, and a maximum number of theoretical crossing points on the external surface of the fibrous texture, each actual crossing point (Pi, P2) corresponding to a change in relative position in the direction of the thickness of the fibrous texture of a warp yarn relative to a weft yarn between two successive warp planes, the number of contact points corresponding to the sum of warp contact point values ​​per centimeter determined for each warp contact point and weft contact point values ​​per centimeter determined for each weft contact point, a warp contact point, respectively a weft contact point, corresponding to a change in relative position in the direction of the thickness of the fibrous texture of a warp yarn, respectively a weft yarn, in a warp plane, respectively in a weft plane, of the weave structure of the fibrous texture.

5. Texture according to claim 4, wherein the single-weave infiltration score Si corresponds to the following formula: Pc^r where Pc is the number of warp planes, Ptr is the number of weft planes, / is a function for identifying real crossover points, i is the current warp plane, and j is the current weft plane.

6. Texture according to claim 4 or 5, wherein the number of contact points N corresponds to the following formula: N - Nch xC x + Ntr x D x , „ . {rtr x Ccn) (rch x Ctr) With: N: Total number of contact points Nch: Number of warp contact points per plane Ntr: Number of weft contact points per plane C = Count (number of warp yarns per cm) D = Weft yarns (number of weft yarns per cm) Pch = Number of warp planes Ptr = Number of weft planes Cch = Number of warp layers Ctr = Number of weft layers.

7. 19 Part of composite material having a fibrous reinforcement texture according to any one of claims 1 to 6 densified by a matrix at least partially formed by chemical vapor phase infiltration.

8. Part according to claim 7, wherein the reinforcing fibrous texture comprises ceramic or carbon fibers.

Images