Reinforcing fiber texture for a composite material part

Abstract

Reinforcing fiber texture for a composite material part A reinforcing fiber texture (20) for a composite material part comprises a three-dimensional or multi-layer weave between layers of warp threads (C1-C10) juxtaposed in the thickness of the fiber texture and layers of weft threads (T1-T10) juxtaposed in the thickness of the fiber texture. The fiber texture having a weave pattern determined on a plurality of warp planes (CH1, CH2) and on a plurality of weft planes. The weave pattern has a single weave infiltrability 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 fiber texture for a composite material part Technical field

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

[0002] A field of application of the invention is the production of parts made of structural composite material, i.e. structural parts with fiber reinforcement and densified by a matrix. Composite materials make it possible to produce parts having a lower overall mass than these same parts when they are 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 multi-layer weaving between a plurality of layers of warp threads and a plurality of layers of weft threads, the reinforcement being densified by chemical gas infiltration (CVI). A 3D weave may for example correspond to an interlock weave weave while a multi-layer weave may for example correspond to a multi-plain, multi-satin or multi-twill weave weave.

[0004] Depending on the 3D or multi-layer weaving pattern used to form the fiber texture, the latter has a more or less good infiltrability, i.e. a capacity for infiltration by the reactive gas used for the CVI. The infiltrability depends in particular on the density of the warp threads passing through two or more weft layers in the thickness of the fiber texture. Indeed, when a warp thread binds two or more layers of weft threads, it creates a preferential path which facilitates the circulation of the gas in the fiber texture.

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

[0006] Furthermore, the number of contact points between the warp threads and the weft threads in a 3D or multi-layer weave influences the deformability and the swell of a fiber texture. A texture having a weave with many contact points is not very deformable and not very swell, which poses problem during shaping in the conformer, the preform then not completely filling the air gap of the conformer.

[0007] There is therefore a need to define fibrous textures formed at least in part by three-dimensional or multi-layer weaving having a good compromise between infiltrability and capacity for deformation and expansion. Presentation of the invention

[0008] For this purpose, the invention proposes a reinforcing fibrous texture for a composite material part, the fibrous texture having a three-dimensional or multi-layer weave between layers of warp threads juxtaposed in the thickness of the fibrous texture and layers of weft threads 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-layer weave, the fibrous texture having a weave pattern determined on a plurality of warp planes and on a plurality of weft planes, characterized in that the weave pattern has a complex weave infiltrability 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 between warp threads and weft threads 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 thread of the skin with respect to a weft thread between two successive warp planes, said warp thread of the skin being located above a warp thread of a layer of warp threads underlying the layer of warp thread of the skin linking at least two layers of weft threads 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 direction of the thickness of the fiber texture of a warp thread, respectively of a weft thread, in a warp plane, respectively in a weft plane, of the weaving weave of the fiber texture.

[0009] The fibrous texture according to the invention comprising a 2D skin on the surface and a 3D or multi-layer weave at the core thus presents a good compromise between:

[0010] - infiltrability, i.e. the capacity of infiltration of the fibrous texture by the gas reagent used for CVI, which helps improve densification by CVI at the core, 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 infiltrability score Sm corresponds to the following formula: ç - pcl^ptr , suchP^iJ)^

[0013] where P ch is the number of warp planes P Tr is the number of weft planes / z is a function for identifying real crossing points of interest i is the current warp plane j is the current weft 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 Chain per plane (counted according to the principle above)

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

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

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

[0020] Pch = Number of plans 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-layer weave between layers of warp threads juxtaposed in the thickness of the fibrous texture and layers of weft threads juxtaposed in the thickness of the fibrous texture, the three-dimensional or multi-layer weave being present on external surfaces of the fibrous texture, the fibrous texture having a weave pattern determined on a plurality of warp planes and on a plurality of weft planes, characterized in that the weave pattern has a single weave infiltrability score greater than or equal to 0.67 and a number of contact points less than 70, the single weave infiltrability score of the fibrous texture corresponding to the ratio between a number of actual crossing points between warp threads of the layer of warp yarn present on an outer surface of the fiber texture and weft yarns of layers of weft yarns and a maximum number of theoretical crossing points on the outer surface of the fiber texture, each actual crossing point corresponding to a change in relative position in the direction of the thickness of the fiber 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 fiber texture of a warp yarn, respectively a weft yarn, in a warp plane,respectively in a weft plane, of the weaving armor of the fibrous texture.,

[0022] The fibrous texture according to the invention formed by 3D or multi-layer weaving thus presents a good compromise between:

[0023] - infiltrability, i.e. the capacity of gas to infiltrate the fibrous texture reagent used for CVI, which makes it possible to improve densification by CVI at the core, and

[0024] - deformation and expansion capacity in order to facilitate the shaping of the fibrous texture.

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

[0026] where P a is the number of chain planes P Tr is the number of raster planes / is a function for identifying real crossing points i is the current chain plan j is the current raster plane

[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 Chain per plane (counted according to the principle above)

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

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

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

[0033] Pch = Number of plans in Chain

[0034] Ptr = Number of frames in frame

[0035] Cch = Number of layers of Chains Ctr = Number of frame layers.

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

[0037] [Fig. 1A-1R] Figures 1A to 1R illustrate successive planes of a weave armor of a fibrous texture with three-dimensional weave at the core and two-dimensional weave at the skin,

[0038] [Fig.2] [Fig.2] illustrates a grid of one of the external surfaces of a texture fibrous having the weaving armor of figures IA to IR used for the calculation of an infiltrability score in accordance with the invention,

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

[0040] [Fig.4] [Fig.4] illustrates an example of assigning touchpoint values in a 3D woven fibrous texture in accordance with the invention,

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

[0042] [Fig. 6A-6L] Figures 6A to 6L illustrate successive planes of a weave armor of a fibrous texture with three-dimensional weaving at the core and two-dimensional weaving at the skin in accordance with an 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 embodiments

[0044] The invention applies to the definition of fibrous textures having a three-dimensional (3D) or multi-layer weaving pattern between a plurality of layers of warp threads and a plurality of layers of weft threads and intended to form a fibrous reinforcement of a part made of composite material, the fibrous texture being at least partially consolidated or densified by chemical gas infiltration (CVI). The fibrous texture is intended to form the fibrous reinforcement of a part made of composite material composite, in particular but not exclusively, a part made of ceramic matrix composite (CMC) material, i.e. comprising a fibrous reinforcement, for example made of carbon or ceramic fibers, densified by a matrix at least partially made of ceramic.

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

[0046] By "multi-layer weave" is meant here a 3D weave with several weft layers whose basic weave of each layer is equivalent to a conventional 2D fabric weave, such as a plain, satin or twill weave, but with certain points of the weave which bind the weft layers together. Known examples of multi-layer weave weaves are multi-plain, multi-satin and multi-twill weaves.

[0047] A 3D or multi-layer weave defines the way in which the warp threads intertwine with the weft threads and vice versa according to an elementary pattern for each plane of the weave. The pattern of the weave is defined on a plurality of warp sectional planes, also called warp planes, which show the path of the warp threads relative to the weft threads (represented in section) in the thickness of a fiber texture for a given column of warp threads, i.e. the path of one warp thread for each layer of warp threads, as well as on a plurality of weft sectional planes, also called weft planes, which show the path of the weft threads relative to the warp threads (represented in section) in the thickness of a fiber texture for a given column of weft threads, i.e. the path of one weft thread for each layer of weft threads.The warp and weft cross-sectional planes are repeated in order throughout the weaving of the fiber texture. [Fig.2] shows an example of a multi-layer 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 from 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 material constituting the matrix 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 material constituting the matrix by decomposition of one or more constituents of the reactive gas or by reaction between several constituents, these constituents forming the precursor of the matrix. Such a process is described in particular in US patent 9,845,534.

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

[0050] Calculating an infiltrability score for a fiber texture makes it possible to determine a value representative of its infiltration potential by the gas(es) used for the CVI. As described below in detail, a “simple weave infiltrability” score makes it possible to determine a value representative of the infiltration potential of a 3D or multi-layer weave weave when the latter is present on the external surfaces of the fiber texture, i.e. directly accessible by the reactive gas of the CVI. A “complex weave infiltrability” score makes it possible to determine a value representative of the infiltration potential of a weave weave comprising an internal part or core formed by a 3D or multi-layer weave and an external part or skin having a two-dimensional weave and covering the 3D or multi-layer weave.

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

[0052] An example of calculating an infiltrability score of a fibrous texture illustrated in Figures 1A to 1R is now described. Figures 1A to 1R represent eighteen successive warp planes CH1 to CH18 of a weave of a fibrous texture 10 obtained by 3D weaving with core 12 and two-dimensional weaving with skin 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 infiltrability score begins by squaring 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 corresponding to an intersection between a warp plane CH1 to CH 18 and a weft plane TRI to TRI8. The square cells of the grid represent the behavior of the warp yarn Cii to Ci 18 of the layer of warp yarns Ci of the skin 16 respectively on the eighteen warp planes CH1 to CH 18 and weft TRI to TR18. For example, the warp yarn Cn visible on the warp plane CH1 of [Fig.lA] is represented in [Fig.2] in the left column from bottom to top of the figure and so on for the warp yarns Ci2 to Ci 18 from left to right in [Fig.2]. The square cells in black represent warp yarns visible on the surface of the fiber texture while the square cells in white represent weft yarns visible on the surface of the fiber texture.

[0054] In the following explanation of the calculation of the infiltrability score, we generalize by noting PCh the number of warp planes, and Ptr that of weft. We also note Cch the number of layers in warp, and Ctr that in weft. In the example of figures 1A to IR, Cch = Ctr.

[0055] Noting ' the current warp plane, and j the current weft plane, and y) the position of the warp thread k, defined by the number of wefts 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 in [Fig.2] of bottom up is C(l,l) = 1 (weft yarn above warp yarn Cn), C(l,2) = 1 (yarn above the warp thread Ci2), C(l, 3) = 1 (weft thread above the warp thread Cn), C(l, 4) = 0 (weft thread below the warp thread Ci 4), C(l, 5) = 0 (weft thread below the warp thread Ci5), C(l, 6) = 0 (weft thread below the warp thread Ci6), C(l, 7) = 1 (weft thread above the warp thread Cn), C(l, 8) = 1 (weft thread above the warp thread Ci 8), C(l, 9) = 1 (weft thread above the warp thread Ci 9), C(l, 10) = 0 (weft thread below the warp thread Ci i0), C(l, 11) = 0 (weft thread below the warp thread Ci n), C(l, 12) = 0 (weft thread weft below the warp thread Cn2), C(l, 13) = 1 (weft thread above the warp thread Ci n), C(l, 14) = 1 (weft thread above the warp thread Ci i4), C(l, 15) = 1 (weft thread above the warp thread Ci i5), C(l, 16) = 0 (weft thread below the warp thread Ci i6), C( 1, 17) = 0 (weft thread below the warp thread Ci i7) C(l,18) = 0 (weft thread below warp thread Ci [8). ,

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

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

[0060] Point [-j, j +j) = Point (Pch + j, j+j), for l <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 makes it possible to isolate the real crossing points, represented by Pi and P2 in Figure 2, 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 real warp-weft crossing points are those for which the function f is equal to 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 thread relative to a weft thread between two successive warp planes.

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

[0068] The “simple armor” infiltrability score, noted Sq, can be calculated with the following formula:

[0069] '

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

[0071] For example, if we consider that [Fig.2] represents the surface of a fibrous texture without the two-dimensional skin, namely that the warp threads present in the first layer of warp threads already provide deep bonds, the simple weave infiltrability 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 multi-layer weave and an outer part or skin having a two-dimensional weave and covering the 3D or multi-layer weave as is the case in Figures 1A to 1R and 2, the cells where a deep binding point exists are first identified. A deep binding point corresponds to a warp yarn of a layer of warp yarns underlying the warp yarn layer of the skin which binds at least two layers of weft yarns in the thickness of the fiber texture. The cells where a deep binding point exists are represented with a point Lpa or Lpd in [Fig.2], Lpa corresponding to an ascending deep binding point and Lpd corresponding to a descending deep binding point.To do this, simply look, warp plane by warp plane, at the behavior of the warp yarn C2i to C21 8 (figures IA to IR), and identify the positions where two or more layers of weft are linked.

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

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

[0075] The cells (i, j) for which g(L j ) = 1 are identified by a point Lpd (downward link) (figure 2). The cells (i, j) for which g(i, j) = -1 are identified by a point Lpa (upward link) ([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 in [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 which are close to a deep binding of a warp thread in the fibrous texture. In other words, each actual crossing point of interest Pi corresponds to a change in relative position in the direction of the thickness of the fibrous texture of a warp thread of the skin with respect to a weft thread between two successive warp planes, the warp thread considered of the skin being located above a warp thread of a layer of warp threads underlying the warp yarn layer of the skin binding at least two layers of weft yarns in the thickness of the fibrous texture

[0079] The real crossing points of interest between warp and weft threads of the skin are those for which the function h is equal to 1 (h=0 for the others). To do this, it is sufficient to examine the four cells adjacent to each of these points.

[0080] The “multi-layer infiltrability” score, noted Sm, can be calculated with the formula next: , if 3 (ï, j) such that P}(i, j) otherwise

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

[0082] The infiltrability score of the weave armor shown in Figures 1A to 1R is equal to 0.22, obtained on the basis of the number of points Pi present in [Fig.2] divided by the maximum number of theoretical crossing points on the external surface of the fiber texture, i.e. 72 / 324. The fiber texture having the weave armor defined in Figures 1A to 1R has an unsatisfactory infiltration score because it is less than 0.67.

[0083] Calculating the number of contact points between warp threads and weft threads makes it possible to evaluate the deformation (flexibility) and expansion capacity of a fibrous texture.

[0084] The calculation of the number of contact points for the warp yarns of the fiber texture begins with the calculation for each warp yarn of the layers of warp yarns of the fiber texture of a value of warp contact points. A contact point corresponds to a change in relative position in the direction of the thickness of the fiber texture of a warp yarn in a warp plane of the weave of the fiber texture. The value of a warp contact point is determined according to the number of layers of weft yarns crossed by a warp yarn considered corresponding to a depth of the binding point in the layer(s) of weft yarns, the calculation being repeated for each warp weave plane. As illustrated in the example of [Fig. 4], the warp yarn Ca has two contact points. A value equal to 1 is assigned to the first contact point of the warp yarn Ca on the left in [Fig.4] since the yarn Ca here passes through a layer of weft yarns Ta. We assign a value equal to 2 to the second point of contact of the warp yarn Ca on the right in [Fig.4] since the yarn Ca here passes through two layers of weft yarns Ta and Tb. Similarly, the warp yarn Cb has two points of contact to which we assign . respectively a value equal to 1 (first point of contact of the warp thread Cb on the left in [Fig.4]) since the thread Cb here passes through a layer of weft threads Tb and a value equal to 2 (second point of contact of the warp thread Cb on the right in [Fig.4]) since the thread Cb here passes through two layers of weft threads Tb and Te. the warp thread Ca has two points of contact. A value equal to 1 is assigned to each of the two points of contact of the warp thread Ce since the thread Ce here passes twice through a single layer of weft threads Te.

[0085] More generally, when a warp thread crosses n layers of weft threads, this corresponds to a contact point to which the value n is assigned.

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

[0087] Calculating the number of contact points then includes calculating a value of warp contact points per centimeter. For this purpose, the texture of the weft threads, corresponding to the number of weft threads per centimeter, also called "picking per centimeter", is calculated in order to obtain a figure for the number of contact points per centimeter. To manage the textures, an average weighting of the contact on a layer is calculated and multiplied by the number of threads per cm in each direction.

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

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

[0090] - calculation of a value of contact points in weft 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 for the number of contact points per centimeter.

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

[0092] The calculation of the number of contact points in a fibrous texture can be obtained with 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 Chain per plane (counted according to the principle above)

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

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

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

[0100] P ch = Number of plans in Chain

[0101] Ptr = Number of frames in frame

[0102] Cch = Number of layers of Chains

[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 expansion and deformability relative to each other.

[0105] The number of contact points calculated for the fiber texture having the weave pattern defined in Figures 1A to 1R is 65, which is satisfactory because it is less than 80.

[0106] Thus, the weaving armor defined in figures 1A to 1R is not retained to produce a fiber texture according to the invention due to an infiltrability score of less than 0.67 which does not ensure good chemical infiltration in the gas phase at the core, resulting in excessively high matrix deposition gradients between the external surface and the core of the texture.

[0107] The table below shows the infiltrability scores and the number of contact points calculated using the methods detailed above for known 3D interlock weaves, with and without 2D skin, and known multi-layer multi-plain, multi-satin and multi-twill weaves: Armor Type Infiltration Score Number of Contact Points Multi-canvas 0.4 (Sm) 152 Multi-satin 0.19 (S m) 34 Interlock 0.5 (S ;) 90 Interlock + Surface Skin 0.25 (Sm) 90 Multi-twill 0.67 (Sm) 115

[0108] It is found that each of the known armors listed above has at least one infiltrability score lower than 0.67 or a number of contact points higher than 80. In other words, none of the known 3D or multi-layer armors satisfies the compromise between infiltrability and capacity for deformation and expansion defined by the present invention.

[0109] We now present examples of weaving armors for fiber textures for reinforcing composite material parts which satisfy the compromise between infiltrability and deformation and expansion capacity defined by the present invention, namely armors having an armor infiltrability 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 weave of a 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 Cio and ten layers of weft yarns Ti to Ti0.

[0111] The weaving armor defined in Figures 5A to 5F consists of a 3D weave present directly on the external surfaces of the fiber texture, that is to say with for example the warp threads Cn to Ci6 of the first layer of warp threads Ci which already deeply binds at least two layers of weft threads to the external surface 20a of the fiber texture 20. As explained above, the infiltrability score of the fiber texture 20 therefore corresponds to the simple weave infiltrability score calculated with the following formula: [0H2] ' $1 - PchxPtr

[0113] The fibrous texture 20 has an infiltrability score of 0.67 which is equivalent to the infiltrability score of a multi-twill weave. On the other hand, the fibrous texture 20 has a number of contact points equal to 63, much lower than the number of contact points equal to 115 for the multi-twill weave and especially lower than 80 corresponding to the maximum number of contact points defined in the present invention.

[0114] Figures 6A to 6L represent twelve successive warp planes CH1 to CH12 of a weave of a fibrous texture 30 obtained by 3D weaving with core 32 and two-dimensional weaving in skin 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 Cio and ten layers of weft yarns Ti to Ti0

[0115] As explained above, the infiltrability score of the fibrous texture 30 therefore corresponds to the multi-layer infiltrability 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 infiltrability score of 0.33 and a number of contact points equal to 77. The weaving armor of the fibrous texture 30 therefore meets the conditions for proposing a good compromise according to the invention between infiltrability and capacity for deformation and expansion.

[0118] Figures 7A to 7H represent eight successive warp planes CH1 to CH8 of a weave 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 Cio and eleven layers of weft yarns Ti to Ti b

[0119] The weaving pattern defined in Figures 7A to 7H consists of a 3D weave present directly on the external surfaces of the fiber texture, that is to say with for example the warp threads Cn to Ci8 of the first layer of warp threads Ci which already deeply binds at least two layers of weft threads to the external surface 40a of the fiber texture 40. As explained above, the infiltrability score of the fiber texture 40 therefore corresponds to the simple weave infiltrability score calculated with the following formula:

[0120] $1 “ Pc^tr

[0121] The fibrous texture 40 has an infiltrability score of 0.5. The fibrous texture 40 also has a number of contact points equal to or less than 80, corresponding to the maximum number of contact points defined in the present invention. The weaving armor of the fibrous texture 40 therefore meets the conditions for providing a good compromise according to the invention between infiltrability and capacity for deformation and expansion.

[0122] The chemical nature of the threads 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), may be used, the fibrous texture being densified by a matrix at least partially formed by chemical vapor infiltration.

Claims

Claims

1. Reinforcing fibrous texture (30) for a composite material part, the fibrous texture having a three-dimensional or multi-layer weave (32) between layers of warp threads (Ci, Cio) juxtaposed in the thickness of the fibrous texture and layers of weft threads (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 multi-layer weave, the fibrous texture having a weave pattern determined on a plurality of warp planes (CH 1-CH 12) and on a plurality of weft planes, characterized in that the weave pattern has a complex weave infiltrability 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 real crossing points of interest (Pi) between warp threads and weft threads of the skin (36) of the fibrous texture (30) and a maximum number of theoretical crossing points on said skin, each real 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 thread of the skin with respect to a weft thread between two successive warp planes, said warp thread of the skin being located above a warp thread of a layer of warp threads underlying the layer of warp thread of the skin linking at least two layers of weft threads 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 direction of the thickness of the fiber texture of a warp thread, respectively of a weft thread, in a warp plane, respectively in a weft plane, of the weaving weave of the fiber texture.,

2. Texture according to claim 1, wherein the complex armor infiltrability 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 weft planes h is a function for identifying real crossing points of interest i is the current warp plane j is the current weft plane

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

4. Reinforcing fibrous texture (20) for a composite material part, the fibrous texture comprising a three-dimensional or multi-layer weave between layers of warp threads (Ci-Ci0) juxtaposed in the thickness of the fibrous texture and layers of weft threads (TrTio) juxtaposed in the thickness of the fibrous texture, the three-dimensional or multi-layer weave being present on external surfaces (20a, 20b) of the fibrous texture (20), the fibrous texture having a weave pattern determined on a plurality of warp planes (CHrCH6) and on a plurality of weft planes, characterized in that the weave pattern has a single weave infiltrability score greater than or equal to 0.67 and a number of contact points less than 70,the simple weave infiltrability score of the fibrous texture corresponding to the ratio between a number of real crossing points (Pb P2) between warp threads of the warp thread layer present on an external surface (20a) of the fibrous texture (20) and weft threads of weft thread layers, and a maximum number of theoretical crossing points on the outer surface of the fiber texture, each actual crossing point (Pi, P2) corresponding to a change in relative position in the direction of the thickness of the fiber texture of a warp thread relative to a weft thread 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 fiber texture of a warp thread, respectively a weft thread, in a warp plane, respectively in a weft plane, of the weave of the fiber texture.

5. Texture according to claim 4, wherein the single armor infiltrability score Si corresponds to the following formula: Pc^r where P ch is the number of warp planes P Tr is the number of weft planes / is a function of identifying real crossing points i is the current warp plane j is the current weft plane

6. Texture according to claim 4 or 5, in which 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 contact points in Warp per plane Ntr: Number of contact points in Weft per plane C = Count (number of warp threads per cm) D = Duitage (Number of weft threads per cm) Pch = Number of planes in Warp Ptr = Number of planes in Weft Cch = Number of layers of Warps Ctr = Number of layers of wefts.

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

8. A part according to claim 7, wherein the reinforcing fibrous texture comprises ceramic or carbon threads.

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