Classifications

• • D—TEXTILES; PAPER
  • D03—WEAVING
  • D03D—WOVEN FABRICS; METHODS OF WEAVING; LOOMS
  • D03D19/00—Gauze or leno-woven fabrics
• • D—TEXTILES; PAPER
  • D03—WEAVING
  • D03D—WOVEN FABRICS; METHODS OF WEAVING; LOOMS
  • D03D15/00—Woven fabrics characterised by the material, structure or properties of the fibres, filaments, yarns, threads or other warp or weft elements used
  • D03D15/40—Woven fabrics characterised by the material, structure or properties of the fibres, filaments, yarns, threads or other warp or weft elements used characterised by the structure of the yarns or threads
  • D03D15/43—Woven fabrics characterised by the material, structure or properties of the fibres, filaments, yarns, threads or other warp or weft elements used characterised by the structure of the yarns or threads with differing diameters
• • D—TEXTILES; PAPER
  • D10—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
  • D10B—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
  • D10B2401/00—Physical properties
  • D10B2401/06—Load-responsive characteristics
  • D10B2401/063—Load-responsive characteristics high strength
• • D—TEXTILES; PAPER
  • D10—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
  • D10B—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
  • D10B2505/00—Industrial
  • D10B2505/02—Reinforcing materials; Prepregs

Definitions

• the invention relates to the field of the textile industry, and more particularly to textiles used as reinforcement for composite materials. It is more specifically a complex formed by a stack of reinforcing layers for impregnation with a polymeric resin, and in particular thermosetting resin. It relates more specifically to a configuration of this type of complex allowing one of its layers to provide both a mechanical strengthening function, and drainage of the impregnating resin for closed molds.
• the manufacture of composite materials from fibrous reinforcements can be achieved by infusion techniques, whereby the resin is introduced into a mold at particular points, and moves within or around the fibrous layers. towards suction points.
• the infusion process is based on three fundamental physical principles which are the pressure difference, the viscosity of the resin and the permeability. Indeed, the migration of the resin through the textile structure (impregnation) can not take place if the permeability is not sufficient and if the pressure in the mold is constant.
• the permeability of a reinforcement represents its ability to be traversed by a fluid, in this case the resin. At the microscopic scale, it is related to the microporosity of the locks (assembly of fibers). On the mesoscopic scale, it is linked to the spaces separating the constituent locks from the weaving of the reinforcement. At the macroscopic scale, it depends on the weaving of the reinforcement. Permeability is expressed in m 2 .
• Classical roving fabrics (twill, cloth, standard gauze, etc.) or Non Crimp Fabrics (NCF) used in the infusion process have a permeability of the order of 10 ⁇ 10 to 10 ⁇ n m 2 for the glass. This permeability is generally not sufficient to ensure the correct filling of the piece which is often large.
• two types of infusion can be used for monolithic structures. It is thus possible to carry out an infusion with external drainage. In this case, the resin flows with a draining fabric, highly permeable, placed above the stack of preformed fibers.
• the external draining is then removed from the room using a tear-off fabric.
• the major disadvantage of this method is the large number of waste (tearing tissue, external draining net) and the time of setting up consumables.
• the infusion process with internal drainage is also known.
• the draining fabric is positioned inside the textile structure. It is a very porous layer allowing a good flow of the resin through the preform. In general, it is a Continuous Filament Mat or a synthetic net that will stay in the room.
• the major disadvantage of this type of product is the impact on the mechanical properties due to the increase of the resin content in the final laminate.
• the fibrous webs are composed of unidirectional structures comprising son of high strength and high tenacity. Each of these plies is deformed so that the weft yarns have an inclination that is not perpendicular to the warp direction. Several of these plies are associated, combining different inclinations of the reinforcing son.
• This assembly is performed without insertion of core layers facilitating creep. It is the inclination of the different threads of the superposed sheets, which allows the creep of the resin.
• This solution if it has the advantage of not including fibrous materials other than those of the reinforcing layers, however has the disadvantage of a relatively low permeability to the resin in the warp direction.
• the invention therefore proposes to provide a solution which has both good longitudinal permeability to the resin for easy impregnation during infusion process, combined with high mechanical performance for the composite obtained.
• the invention relates to a reinforcing textile structure for composite materials, intended to form an intermediate layer to be integrated into a textile complex formed of a stack of textile layers for impregnation with a polymeric resin.
• a set of weft threads A set of weft threads
• the invention consists in producing an intermediate layer which has good mechanical properties, because it is made from high-tenacity yarns, and which has good resin permeability in the warp direction and / or frame.
• This layer thus acts as a "structural internal draining", thus combining the advantages in terms of permeability of a synthetic internal draining and the mechanical characteristics close to a standard reinforcement.
• the configuration of the gauze pitch with two son of different nature makes some of these son, namely high-tenacity son, have a limited or no filling, and define between them channels in which the resin can easily move.
• the low clogging of the high-tenacity warp yarns is all the more important as the tension difference between the two types of warp yarns is important. It is also to a lesser extent a function of the difference of title between these two types of son. This makes it possible to work with voltage differences on the two types of warp yarns, so that the yarn of lower title supports the largest embossing.
• the yarns of the second type may be of different natures, namely either synthetic organic yarns, or even high-tenacity yarns similar to the main threads.
• the entire characteristic layer can thus be made based on high-tenacity yarns, which may be advantageous for certain properties of compatibility, or heat resistance, although the yarn of the second type does not does not participate in the mechanical strength of the product.
• the reinforcement is substantially balanced. This makes it possible to create channels not only in the warp direction, but also in the weft direction, thus with a large permeability in both directions.
• the permeability needs to be high in only one direction, namely the warp direction, lower-order weft threads can be used.
• the influence of the binding yarns can be all the more reduced if the mass density of the warp yarns of the first type is greater by more than eight or at least three or four times that of the warp threads of the second type.
• the creep capacity of the resin can be modulated according to the width of the channels defined between the main threads.
• these channels between son are of the order of magnitude of the width of a wire.
• the pitch between the warp (and weft) can be between two and three times the width of one of these son.
• the size of the channels between the warp threads of higher strength can advantageously be between 0.5 and 3 mm for good permeability in the warp direction. Indeed, below 0.5 mm the gap is not sufficient to let the resin and above 3 mm, there is a phenomenon of reinforcements nesting during the evacuation. It can thus be seen that textile structures placed on either side of the draining fabric can plug the channels with the application of vacuum and drop the permeability of the product.
• This intermediate layer may be associated with one or more additional layers to increase creep capacity.
• these additional layers are made from high-tenacity yarns and identical to that of the reinforcing layers of the complex.
• It may for example be a veil, or a mat of glass fibers, which by its volume facilitates the passage of the resin during molding, and improves the draining effect of the characteristic intermediate layer, without adding of synthetic material.
• the use of a glass mat also improves the isotropy of the complex, by attenuating the anisotropy induced by the directions of the reinforcing son of the structural draining layer.
• this additional layer may itself be composed of a stack of elementary layers if necessary.
• Such an intermediate layer has properties of high permeability at least in one direction, combined with high mechanical properties.
• Figure 1 is a top view of a textile structure forming the draining intermediate layer of a complex according to the invention.
• Figures 2 and 3 are views in section respectively according to the plans ⁇ - ⁇ and III-
• FIG. 4 is a sectional view of a complex according to the invention, including the intermediate layer of FIG. Way of realizing the invention
• the draining and structuring intermediate layer as illustrated in FIG. 1 comprises weft yarns 2 and warp yarns 3, 4.
• the weft yarns 2 are arranged in parallel, and have virtually zero packing.
• the warp threads 3, 4 are associated in pairs.
• the weaving is performed using a weave no gauze between the two warp threads 4 and 3 on the one hand, and the weft thread 2 on the other hand.
• the two warp threads 3,4 intersect around the weft.
• the main warp threads 3 are all arranged on the same side of the sheet of weft threads 2, and the warp threads 4 of the second type, that is to say, of the title weaker, pass from one side to another of the structure, with a large emleidage.
• weft yarn 2 1,200 tex glass yarn, with a basis weight of 468 g / m 2 ;
• warp 3 of the first type 1,200 tex glass yarn, with a mass per unit area of 438 g / m 2 ;
• warp 4 of the second type polyester thread of 28 tex, with a weight per unit area of 16 g / m 2 ;
• Weft frame 2 glass fiber 600 tex, with a basis weight of 240 g / m 2 ;
• First type 3 warp 600tex glass fiber with a basis weight of 240 g / m 2 ;
• Second type 4 warp 28 tex polyester yarn with a basis weight of 20 g / m 2 ;
• Frame 2 glass fiber 600 tex, with a basis weight of 276 g / m 2 ;
• First type 3 glass fiber of 1200 tex with a weight per unit area of 280 g / m 2 ;
• Second type 4 28 tex polyester yarn with a weight per unit area of 8 g / m 2
• the woven glass wires 2 are finer, but are arranged with a smaller pitch, so as to form a spacing of the order of one millimeter, corresponding to the width of a weft yarn.
• Frame 2 glass fiber 600 tex with a basis weight of 276 g / m 2 ;
• first type 3 warp yarn 600 tex glass yarn with a weight per unit area of 240 g / m 2;
• Permeability is a physical characteristic that represents the ease with which a material allows the transfer of fluid through a connected network.
• Darcy's Law makes it possible to connect a flow rate to a pressure gradient applied to the fluid by virtue of a characteristic parameter of the medium traversed, namely the permeability k.
• the permeability can be measured along 3 axes.
• the permeability indicated in the table above corresponds to the permeability measured in the plane of the reinforcement, in the warp direction.
• the draining properties of this characteristic layer can be expressed in complexes used to make composite parts.
• Such complexes include a plurality of backing layers chosen for their mechanical properties.
• the draining layer 1 can be integrated within a stack of several reinforcing layers 11-16 made by weaving warp 20 and weft 21 yarns, and whose number and orientations are determined according to the overall mechanical properties sought for the final composite part.
• the reinforcing structure according to the invention makes it possible to combine both structural reinforcement properties with good permeability thus making it possible to obtain a draining structural reinforcement.

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• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Woven Fabrics (AREA)
• Reinforced Plastic Materials (AREA)

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Publications (1)

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Citations (6)

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• 2014
  • 2014-03-04 FR FR1451734A patent/FR3018285B1/fr active Active
• 2015
  • 2015-03-04 ES ES15714561T patent/ES2895103T3/es active Active
  • 2015-03-04 CN CN201580021207.XA patent/CN106460259A/zh active Pending
  • 2015-03-04 WO PCT/FR2015/050520 patent/WO2015132526A1/fr active Application Filing
  • 2015-03-04 US US15/123,129 patent/US20170067191A1/en not_active Abandoned
  • 2015-03-04 PL PL15714561T patent/PL3114262T3/pl unknown
  • 2015-03-04 KR KR1020167027109A patent/KR20160130259A/ko unknown
  • 2015-03-04 PT PT15714561T patent/PT3114262T/pt unknown
  • 2015-03-04 MA MA039491A patent/MA39491A/fr unknown
  • 2015-03-04 EP EP15714561.6A patent/EP3114262B1/fr active Active

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