Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
  • B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
  • B29C70/06—Fibrous reinforcements only
  • B29C70/08—Fibrous reinforcements only comprising combinations of different forms of fibrous reinforcements incorporated in matrix material, forming one or more layers, and with or without non-reinforced layers
  • B29C70/083—Combinations of continuous fibres or fibrous profiled structures oriented in one direction and reinforcements forming a two dimensional structure, e.g. mats
  • B29C70/085—Combinations of continuous fibres or fibrous profiled structures oriented in one direction and reinforcements forming a two dimensional structure, e.g. mats the structure being deformed in a three dimensional configuration
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B38/00—Ancillary operations in connection with laminating processes
  • B32B38/08—Impregnating
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
  • B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
  • B29C70/28—Shaping operations therefor
  • B29C70/40—Shaping or impregnating by compression not applied
  • B29C70/42—Shaping or impregnating by compression not applied for producing articles of definite length, i.e. discrete articles
  • B29C70/46—Shaping or impregnating by compression not applied for producing articles of definite length, i.e. discrete articles using matched moulds, e.g. for deforming sheet moulding compounds [SMC] or prepregs
  • B29C70/48—Shaping or impregnating by compression not applied for producing articles of definite length, i.e. discrete articles using matched moulds, e.g. for deforming sheet moulding compounds [SMC] or prepregs and impregnating the reinforcements in the closed mould, e.g. resin transfer moulding [RTM], e.g. by vacuum
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
  • B29L2031/00—Other particular articles
  • B29L2031/06—Rods, e.g. connecting rods, rails, stakes

Definitions

• the invention relates to a method for manufacturing a mechanical component such as an aircraft landing gear strut.
• This assembly is then installed in a mold for injecting resin into the various layers carried by the mandrel before polymerizing this resin, for example by heating, to form a rigid raw rod that can be machined at its interfaces to form screeds.
• the braiding of the reinforcing fiber layers is then ensured with a braiding installation which is represented in FIG. 1 by being marked with 1.
• This installation essentially comprises a ring 2 extending in a vertical plane, the axis of revolution AX of this ring is thus horizontal.
• This ring 2 carries a set of coils of reinforcing fibers 3, converging towards a region located on the axis AX and offset from the plane of the ring.
• the mandrel which is marked by 4 is moved along the axis AX to cross the ring 2 beyond the point of convergence of the fibers.
• the coils carried on the ring 2 by motorized mobile supports are actuated to manufacture a sock of reinforcing fibers on the outer face of this mandrel 4.
• This sock covers the. -mandrin on all his length once it has completely traversed the ring, that is to say once it is located beyond the point of convergence of the fibers.
• the reinforcing fiber layer is then cut downstream of the mandrel, and the mandrel is disassembled and then placed behind the ring, in order to cross it again for the formation of a second layer of reinforcing fibers radially superimposed on the first.
• a braided layer comprises, on the one hand, said spindle fibers 8 and 9 which are inclined for example about thirty degrees on one side and the other with respect to the axis AX, and secondly longitudinal fibers 11, parallel to the axis AX, which are held in position by the spindle fibers 8 and 9 which interlace them.
• connecting rod In such a connecting rod, it is essentially the longitudinal fibers that support the mechanical stresses occurring when the link is biased in traction-compression along the axis AX, and when it is biased in bending about any axis normal to the axis AX .
• the longitudinal fibers 11 are in fact corrugated instead of being straight, which penalizes the level of mechanical stresses they are able to support according to AX direction.
• This loss of resistance in the longitudinal direction is all the more important as the corrugation of the longitudinal fibers is high, since the tension applied to the fibers during the braiding must itself be important in order to ensure the greatest overall compactness possible.
• the object of the invention is to propose a solution to remedy this drawback.
• the subject of the invention is a method for manufacturing a mechanical member made of a composite material, such as a rod made of composite material, comprising successive operations for applying reinforcement fiber layers braided all around a mandrel and over all or part of the length of this mandrel being superimposed radially to one another, comprising between two operations of application of braided reinforcing fiber layers, a step:
• each pultruded element being oriented longitudinally and extending over at least a portion of the length of the mandrel;
• the pultruded elements constitute a set of fibers which remain substantially rectilinear after assembly with the braided layers and after injection and polymerization of the resin, which significantly increases the mechanical strength in the longitudinal direction.
• each pultruded element is of the solid rod type.
• the invention also relates to a method as defined above, in which the fixing of each pultruded element applied against the same layer of reinforcing fibers is provided with a product of glue or resin type.
• the subject of the invention is also a method as defined above, in which the fixing of each pultruded element applied against the same layer of reinforcing fibers is ensured with a link passed around the assembly formed by the mandrel with the layers. he wears and pultruded elements to fix.
• the subject of the invention is also a process as defined above, in which a plurality of pultruded elements which are regularly spaced from each other around the longitudinal direction of the mandrel are applied against the same layer of braided fibers.
• the invention also relates to a method as defined above, in which different pultruded elements are assembled by connecting them to each other by one or more transverse links to form a rack-type assembly, before setting up this system. assembly on the same layer of reinforcing fibers.
• Figure 1 is a schematic representation showing in perspective a known braiding machine with a mandrel for receiving a layer of braided fibers
• FIG. 2 is a diagrammatic cross-sectional view showing the layers constituting a connecting rod of known composite material
• Figure 3 is a schematic view showing a portion of braided reinforcing fibers shown in perspective
• Figure 4 is a schematic cross-sectional view of a cylindrical section rod body manufactured according to the method according to the invention.
• Figure 5 is a schematic cross-sectional view of an elliptical cross-section body manufactured in accordance with the method according to the invention.
• Figure 6 is a perspective view of a finished rod made of composite material manufactured with the method according to the invention.
• Figure 7 is a longitudinal sectional view of a rod made of composite material manufactured according to the method according to the invention.
• Figure 8 is a schematic view of an assembly of pultruded elements before placement and attachment to a braided layer.
• the idea underlying the invention is to use a braiding manufacturing process in which prepolymerized or polymerized rectilinear rods, formed of pultruded reinforcing fibers, are integrated by placing them longitudinally between the consecutive braided fiber layers.
• longitudinal rods are integrated into the connecting rod which are perfectly rectilinear and thereby significantly increase the mechanical strength of the connecting rod in tension-compression and bending.
• the pultruded profiles are industrially manufactured constant section composite sections in a continuous process.
• the fibers in the form of coils are unrolled continuously to be impregnated with resin before passing through a heated die polymerizing or prepolymerizing this resin, so as to continuously form a rigid section which is cut portions length desired over the production.
• pultruded profiles are in particular in the form of solid or hollow rods consisting of parallel rectilinear reinforcing fibers being agglomerated to each other by the polymerized or prepolymerized resin.
• the mechanical strength of the pultruded profiles is important along the main axis of the profile for a very competitive manufacturing cost.
• the invention thus consists in integrating pultruded elements between the braiding of reinforcing fiber layers, with an installation of the type shown in FIG. 1 in order to manufacture a connecting rod.
• a connecting rod manufactured in accordance with the invention thus comprises a mandrel 12, which here has a circular section, around which a layer of reinforcing fibers 13 is braided by passing through a braiding installation such as that of the figure 1.
• the pultruded elements 14 are placed on the layer 13, so as to extend longitudinally, that is to say parallel to the axis AX of the connecting rod, being regularly spaced from each other. others around this AX axis.
• These pultruded elements can be fixed by previously applying a product of the glue or resin type on the layer 13.
• Another solution as regards the fixing of the pultruded elements consists in surrounding the assembly with a reinforcing fiber bond, so as to grip these elements against the outer face of the layer 13.
• the following reinforcing fiber layer 16 is braided. This braiding is ensured by moving the assembly formed by the mandrel 12, the braided fiber layer 13, and the pultruded elements 14 through the ring of the braiding installation, along the axis of this ring.
• This operation has the effect of forming a layer of braided fibers which then surrounds the pultruded elements 14 by enclosing them without significantly changing their position.
• the elements 14 remain oriented longitudinally and regularly spaced from each other along the circumference of the layer 13.
• the elements 14 are then firmly gripped between the layers 14 and 16, and they are oriented longitudinally along the axis AX.
• the assembly formed by the mandrel 12, the layers 13 and 16 and the pultruded elements interposed between these layers, is installed in a mold for injecting resin through the layers of reinforcing fibers 14 and 16.
• the pultruded sections are hollow rods, their ends are closed to prevent these rods from filling with resin during the injection phase.
• a heating cycle is then triggered to polymerize this resin, to form a rigid raw link whose interfaces can then be machined by drilling to form screeds, before mounting in these holes metal rings.
• FIG. 4 shows only a set of pultruded elements 14 interposed between two braided layers 13 and 16.
• the method according to the invention makes it possible to interpose between each pair of consecutive braided layers a set of elements pultruded for a generally increase the mechanical strength in traction-compression and bending of this rod, and thereby its resistance to buckling.
• the pultruded elements 14 do not necessarily have to be distributed over the entire circumference of the braided layer which carries them, but they can advantageously be arranged only in certain zones of this circumference, without necessarily being regularly spaced from each other.
• the mandrel 12 has a section which is elliptical instead of circular, to constitute a connecting rod having increased flexural strength around the minor axis of the ellipse corresponding to its section. .
• the resistance in traction-compression is also increased in this rod.
• the first layer 13 ' is braided around the mandrel 12', as for the example of FIG. 4.
• Pultruded elements 14 ' are then placed only at the opposite ends which are furthest from this ellipse. , so as to increase the resistance to bending stress around the minor axis of this ellipse.
• next layer 16 ' is then braided, before proceeding to the establishment of other pultruded elements 17', which are also placed at the level of ends of this ellipse that are furthest apart from each other.
• a new braided layer 18 ' is then applied before proceeding with the resin injection in the assembly and its polymerization.
• the pultruded elements extend essentially along the body of the connecting rod which is indicated by 21 in FIG. 6 where this connecting rod is shown in its finished state.
• This body 21 corresponds to the central region of the connecting rod 19, which is a wall of regulated type, this body 21 having for example a constant section.
• the pultruded elements can marry substantially curved shapes, because their rigidity is relatively important allows them to marry these forms while curving as little as possible.
• these pultruded elements can be placed on curved shapes and their rigidity ensures that they adopt shapes that are not curved enough to offer high mechanical strength.
• the pultruded elements marked here by 14 are arranged radially in the form of three layers, but they do not cover a priori the ends 22 and 23 of the connecting rod 21, that is to say the interfaces of this rod, because these ends have highly scalable unregulated sections not suitable for the application of rectilinear elements.
• the pultruded elements 14 are radially distributed over three layers each interposed between two braided layers, but these elements are integrated into the connecting rod while extending only between the ends 22 and 23 of this connecting rod .
• the pultruded elements can be applied and held one by one on the braided layer which makes them carry. But advantageously, the pultruded elements 14, 14 ', 14'',17' can be prepared prior to their application to form a rack type assembly shown schematically in FIG. 8.
• the pultruded elements are for example arranged flat parallel to each other being spaced regularly from each other, and they are secured to each other by means of several pairs of reinforcing fibers 24 regularly spaced from each other along these elements.
• Each pair 24 then comprises two fibers generally oriented in a direction perpendicular to the general direction of the pultruded elements, and these two fibers are interwoven around each pultruded element, which makes it possible to secure these elements to each other while keeping them parallel and spaced two by two from a predetermined distance.
• the establishment of the elements pultruded on a layer of braided fibers consists of grasping the rack thus formed, to apply it to the outer face of the layer in question, and to stick to it, or to surround the whole with one or more circumferential reinforcing fiber bonds.
• the rod manufactured according to the method according to the invention comprises two interfaces, which are here two screeds. But the invention applies equally well to other types of rods such as landing gears that have an interface at each of their ends and a third interface located between these ends.
• the example of the figures illustrates the implementation of the invention for the manufacture of a rod of composite material. But the invention applies to the manufacture of other types of mechanical members, as for example the manufacture of carbon blades of an aircraft propeller, or the manufacture of a carbon mast intended to equip a sailboat.
• the blades of a propeller as well as the mast of a sailboat are subject to mechanical stresses oriented mainly according to their main direction, that is to say the direction of pultruded elements that are integrated, so that the method according to the invention then offers a significant increase in the mechanical strength for this type of mechanical member.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Composite Materials (AREA)
• Mechanical Engineering (AREA)
• Moulding By Coating Moulds (AREA)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

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• 2010
  • 2010-03-26 FR FR1052230A patent/FR2957844B1/fr active Active
• 2011
  • 2011-03-24 EP EP11711283A patent/EP2552676A1/fr not_active Withdrawn
  • 2011-03-24 WO PCT/EP2011/001479 patent/WO2011116967A1/fr active Application Filing
  • 2011-03-24 CA CA2794411A patent/CA2794411A1/fr not_active Abandoned
  • 2011-03-24 CN CN2011800162509A patent/CN102844171A/zh active Pending
  • 2011-03-24 BR BR112012024389A patent/BR112012024389A2/pt not_active IP Right Cessation
  • 2011-03-24 RU RU2012144846/05A patent/RU2012144846A/ru not_active Application Discontinuation
  • 2011-03-24 JP JP2013501670A patent/JP2013523488A/ja active Pending
  • 2011-03-24 US US13/637,264 patent/US20130105079A1/en not_active Abandoned

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