EP2771169A2 - Method for sealing a fuel tank - Google Patents

Method for sealing a fuel tank

Info

Publication number
EP2771169A2
EP2771169A2 EP12779065.7A EP12779065A EP2771169A2 EP 2771169 A2 EP2771169 A2 EP 2771169A2 EP 12779065 A EP12779065 A EP 12779065A EP 2771169 A2 EP2771169 A2 EP 2771169A2
Authority
EP
European Patent Office
Prior art keywords
protective film
film
box structure
process according
exposed
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP12779065.7A
Other languages
German (de)
French (fr)
Inventor
Mathieu Hottin
Dominique Bailly
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Daher Aerospace SAS
Original Assignee
Daher Aerospace SAS
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Daher Aerospace SAS filed Critical Daher Aerospace SAS
Priority to EP18195582.4A priority Critical patent/EP3446863B1/en
Publication of EP2771169A2 publication Critical patent/EP2771169A2/en
Withdrawn legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64D—EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENTS OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
    • B64D37/00—Arrangements in connection with fuel supply for power plant
    • B64D37/02—Tanks
    • B64D37/06—Constructional adaptations thereof
    • 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
    • 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
    • B29C70/086—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 and with one or more layers of pure plastics material, e.g. foam layers
    • 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
    • B29C70/88—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts characterised primarily by possessing specific properties, e.g. electrically conductive or locally reinforced
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
    • B60K15/00—Arrangement in connection with fuel supply of combustion engines or other fuel consuming energy converters, e.g. fuel cells; Mounting or construction of fuel tanks
    • B60K15/03—Fuel tanks
    • B60K15/03177—Fuel tanks made of non-metallic material, e.g. plastics, or of a combination of non-metallic and metallic material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64C—AEROPLANES; HELICOPTERS
    • B64C3/00—Wings
    • B64C3/34—Tanks constructed integrally with wings, e.g. for fuel or water
    • 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
    • B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/48—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor using adhesives, i.e. using supplementary joining material; solvent bonding
    • 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
    • B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/56—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor using mechanical means or mechanical connections, e.g. form-fits
    • B29C65/562—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor using mechanical means or mechanical connections, e.g. form-fits using extra joining elements, i.e. which are not integral with the parts to be joined
    • 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
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/70—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material
    • B29C66/72—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the structure of the material of the parts to be joined
    • B29C66/721—Fibre-reinforced materials
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2063/00—Use of EP, i.e. epoxy resins or derivatives thereof, as moulding material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2071/00—Use of polyethers, e.g. PEEK, i.e. polyether-etherketone or PEK, i.e. polyetherketone or derivatives thereof, as moulding material
    • 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
    • B29L2031/712—Containers; Packaging elements or accessories, Packages
    • B29L2031/7172—Fuel tanks, jerry cans
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T50/00—Aeronautics or air transport
    • Y02T50/40—Weight reduction
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T156/00—Adhesive bonding and miscellaneous chemical manufacture
    • Y10T156/10—Methods of surface bonding and/or assembly therefor
    • Y10T156/1052—Methods of surface bonding and/or assembly therefor with cutting, punching, tearing or severing
    • Y10T156/1062—Prior to assembly

Definitions

  • the invention relates to a method for sealing a fuel tank.
  • the invention is more particularly adapted to aircraft fuel tanks, formed by an assembly of elements made of a composite material with fiber reinforcement.
  • the fuel tank of an aircraft is generally placed in an empty volume of a box structure, particularly in the structure of the wings.
  • said volume must be sealed, and secondly, the materials constituting said box structure must be protected from any damage that could cause their contact with the fuel. This latter characteristic is particularly relevant in the case where the materials constituting the box structure are organic matrix composite materials, to which the fuel hydrocarbons act as solvents.
  • this protection can be obtained by inserting a bladder into the empty volume of the caisson structure used as a reservoir.
  • This solution is unfavorable for aeronautical applications because the bladder constitutes an additional mass.
  • the internal shape of the empty volume dictated essentially by structural considerations, can be complex and, both the adaptation of the shape of the bladder to this volume, as the introduction of said bladder in this volume are delicate.
  • Another solution of the prior art is to paint the structural parts defining the empty volume of the box structure with a specific primer, resistant to hydrocarbons. This technical solution imposes a painting operation in the manufacturing range and its quality of realization is dependent on the know-how of the operator.
  • the protection is achieved by applying inside the empty volume of the assembled box structure, a liquid sealant based on polythioether. This operation, usually carried out with a brush, is commonly referred to as churning, and turns out to be particularly painful.
  • WO 2007 045466 discloses a fuel tank of material organic matrix composite, as well as methods for making such a reservoir.
  • the fuel tank described in this prior art document is intended for a motorcycle or automobile and constitutes a small volume reservoir.
  • This document discloses two embodiments of such a reservoir, the first constant to mold an envelope made of a thermoplastic material on which reinforced plies are then draped.
  • the second method consists in first producing an envelope made of a laminated composite material and then covering, after firing, the inside of this envelope with a thermoplastic film by blowing or rotomolding this film inside the volume of the reservoir thus constituted.
  • the invention aims at solving the drawbacks of the prior art and for this purpose concerns a method for producing a structural element comprising a panel made of composite material with fibrous reinforcement in an organic matrix obtained by draping and baking, which panel comprises a face liable to be exposed in contact with hydrocarbons, said process comprising the steps of:
  • the protection of the exposed surface is obtained during the manufacture of the elements constituting the box structure at the stage of the elementary part and the application of this protection does not change the assembly time of the structure.
  • the parts are perfectly accessible and the protection is provided uniformly over the entire surface covered by the film.
  • the co-firing of the film and the part ensures the cohesion of the film on the protected surface.
  • the film being thin, the added mass is small.
  • the matrix consists of an epoxy thermosetting resin and the protective film consists of a polyetheretherketone polymer (PEEK) with a thickness of between 0.015 mm and 0.035 mm.
  • PEEK polyetheretherketone polymer
  • the properties of the PEEK film are not affected by the baking of the epoxy resin, said film being otherwise perfectly resistant to the hydrocarbons used as aircraft fuel, it adds only a mass of a few tens of grams per m 2 of surface on which it is applied.
  • the protective film deposited in step b) of the method which is the subject of the invention does not cover the entire face exposed to hydrocarbons.
  • the method that is the subject of the invention makes it possible to preserve areas that are not covered by the protective film, in particular for gluing or assembling with other parts.
  • step b) of the method which is the subject of the invention comprises the operations of:
  • the protective film comprises a layer of a pressure-sensitive adhesive, called PSA, on one of its faces.
  • PSA is the acronym for the English expression "Pressure Sensitive Adhesive”.
  • the protective film is deposited in several layers with overlaps of the edges of said strips.
  • the method which is the subject of the invention is suitable for covering large elementary parts while ensuring the seal between the deposited protective film strips.
  • the method which is the subject of the invention comprises, between steps b) and c), a step consisting of:
  • the invention also relates to a method for manufacturing a box structure having a volume adapted to contain fuel which method comprises the steps of:
  • step ii) of the method is carried out by riveting.
  • step ii) of the process is carried out by gluing.
  • the invention also relates to an aircraft comprising a box structure of which an empty volume is used as a fuel tank, said box structure comprising a structural element comprising a composite panel with fiber reinforcement obtained according to the method which is the subject of the invention.
  • the use of composite materials for the constitution of this box structure associated with the method of protection of these materials makes it possible to achieve a gain in mass compared to the known solutions of the prior art and to facilitate the manufacture of such a structure.
  • the aircraft object of the invention is advantageous both in terms of manufacturing cost and operating cost.
  • FIG. 1 is a partial sectional view and exploded of an embodiment of a box structure according to the invention
  • FIG. 3 shows in perspective and exploded one of the elementary parts of the box structure of Figures 1 and 2 during the production of said part elementary;
  • FIG. 4 is a flowchart showing the steps of the method according to an exemplary embodiment of the invention.
  • the box structure (100) object of the invention consists of a plurality of elementary parts (1 10, 121, 122) made of a composite material with fibrous reinforcement.
  • said composite material comprises carbon fibers in an epoxy resin matrix.
  • the elementary parts are assembled along assembly interfaces (1 12, 1 13). This assembly can be achieved by gluing or co-cooking. Alternatively or jointly, the assembly can be made by riveting. These assembly techniques are known from the prior art and are not discussed further.
  • the interior volume (150) of this box structure is likely to contain fuel.
  • this protective film consists of polyetheretherketone or PEEK.
  • Such films are, for example, marketed under the trademark APTIV® by VICTREX®.
  • mastic 2 ⁇ 2 ⁇ mastic (212, 213) ⁇ 2 ⁇ 2 ⁇ 2 ⁇ 2 ⁇ 2 ⁇ 2 ⁇ 2 ⁇ 2 ⁇ 2 ⁇ 2 ⁇ 2 ⁇ 2 ⁇ 2 ⁇ 2 ⁇ 2 ⁇ 2 ⁇ 2 ⁇ 2 ⁇ 2 ⁇ 2 ⁇ 2 ⁇ 2 ⁇ 2 ⁇ 2 ⁇ 2 ⁇ 2 ⁇ 2 ⁇ 2 ⁇ 2 ⁇ 2 ⁇ 2 ⁇ 2 ⁇ 2 ⁇ 2 ⁇ 2 ⁇ 2 ⁇ 2 ⁇ 2 ⁇ 2 ⁇ 2 ⁇ 2 ⁇ 2 ⁇ 2 ⁇ 2 ⁇ 2 ⁇ 2 ⁇ 2 ⁇ 2 ⁇ , mastic based on polythioether distributed under the name PR by the company Le Joint faci®.
  • FIG 3 according to an exemplary embodiment of an elementary part (1 10) of the box structure object of the invention, said piece is made by draping folds of prepreg fibers.
  • the draping may be partially performed around a core (310) for example around a honeycomb plate.
  • This draping can be automatic or manual.
  • the protective film is placed on the fuel-exposed area of the preform of the workpiece (1 10), for example in the form of a plurality (331, 332) of PEEK film webs.
  • Each strip (331, 332) comprises a zone of overlap with the side which is juxtaposed to it, so that the junction between two strips is sealed.
  • the protective film is here represented in a rectilinear cut.
  • the contour of the film may be more complex so as to save savings (331, 332) of a more complex form.
  • the strips (331, 332) of the protective film are, before being laid, cut to the desired contour.
  • the operation of laying protective films is performed manually. It is greatly facilitated by the fact that the elementary piece is flat, accessible from all sides during this operation.
  • the protective film can also be cut into several strips so as to facilitate handling thereof.
  • the outline of the lé to be deposited on the preform can be projected by laser on said preform according to a known method of the prior art for manual draping.
  • the protective film strips are stabilized on the structure during installation, thanks to the tackiness of the folds previously draped.
  • the protective film strips may be applied to the preform by compacting under a vacuum bag just before said preform is fired.
  • the protective film is advantageously treated on its face in contact with the resin constituting the matrix of the part, by a method to increase the wettability so as to improve the adhesion of the film to the part over its entire surface.
  • Such a treatment consists in increasing the free surface energy of the film so that it is greater than that of the liquid resin and that said resin wets the surface of the film correctly during the cooking operation.
  • this treatment carried out by plasma, UV or ozone, without this list being exhaustive, makes it possible to increase the free surface energy of the treated surface to a value between 55 and 60 Joules. m "1.
  • treatment to improve the wettability is formed on both sides of the protective film.
  • the protective film strips may be coated on all or part of their face. contact with the lamination, with a pressure-sensitive adhesive, or PSA, for example with a silicone-based adhesive, in order to facilitate their installation. So the The method of the invention is also suitable for producing parts from dry fibers, in particular by injection or infusion of resin.
  • the method of the invention comprises a first series of steps corresponding to the realization of the elementary parts.
  • a first step (410) of draping makes it possible to form the preform of the part.
  • the protective film is cut to the target contour to cover all or part of the surface of the part exposed to hydrocarbons.
  • the film strip thus cut is deposited on the preform during a step (430) of removing said strip.
  • This lé is maintained on the preform by the tackiness prepreg folds previously draped, or by the presence of a PSA-type adhesive on all or part of the surface of the web in contact with the preform.
  • the previous steps (420,430) are repeated for different threads to cover the entire hydrocarbon exposed surface of the workpiece.
  • the preform is bagged, during a bagging step (440), and the whole is compacted, during a compaction step (450) by drawing vacuum. together and bagged.
  • the preform is then directed to an autoclave for a cooking step (460).
  • the firing is carried out at a temperature T1 of the order of 180 ° C.
  • the protective film consisting of PEEK withstands perfectly this temperature T1 without undergoing degradation, that is to say without melting and without leakage of the film.
  • the cooking may be partial so as to maintain a possibility of assembly by co-cooking.
  • This assembly can be achieved by gluing, riveting or co-cooking according to methods known from the prior art.
  • step (480) of completion the tightness of the interstices between the parts thus assembled is achieved by laying cords sealing mastic.
  • the invention achieves the desired objectives, in particular it makes it possible to obtain a box structure made of a composite material with a fibrous reinforcement, said box structure comprising an empty volume capable of containing fuel, which structure is obtained economically and reproducibly, with a low added mass to obtain the seal of said empty volume and the protection of the structural materials vis-à-vis the contact with the hydrocarbons.

Abstract

The invention relates to a method for creating a structural element comprising a panel (110, 121, 122) made of a composite material having a fibrous reinforcement in an organic matrix obtained by layup and curing, which panel comprises a face liable to be exposed to contact with hydrocarbons, characterized in that it comprises the steps involving: a. laying up the plies of fibres preimpregnated with a resin that has a first curing temperature, T1, so as to obtain the desired layering effect; b. applying to the face that is exposed to the hydrocarbons a ply consisting of a thin film (130, 131, 132) of a polymer that is resistant to hydrocarbons and able to withstand the curing temperature T1, referred to as the protective film (130, 131, 132); c. curing the entire layered structure under pressure at the temperature T1.

Description

PROCÉDÉ POUR ÉTANCHER UN RÉSERVOIR DE CARBURANT  METHOD FOR TIGHTENING A FUEL TANK
L'invention concerne un procédé pour étancher un réservoir de carburant. L'invention est plus particulièrement adaptée aux réservoirs de carburant d'aéronefs, formés par un assemblage d'éléments constitués d'un matériau composite à renfort fibreux. The invention relates to a method for sealing a fuel tank. The invention is more particularly adapted to aircraft fuel tanks, formed by an assembly of elements made of a composite material with fiber reinforcement.
Le réservoir de carburant d'un aéronef est généralement placé dans un volume vide d'une structure en caisson, notamment dans la structure des voilures. Pour pouvoir contenir le carburant, ledit volume doit être étanche, et d'autre part, les matériaux constituant ladite structure caisson doivent être protégés des éventuelles dégradations que pourrait engendrer leur contact avec le carburant. Cette dernière caractéristique est particulièrement pertinente dans le cas où les matériaux constituant la structure caisson sont des matériaux composites à matrice organique, vis-à-vis desquels les hydrocarbures du carburant agissent comme des solvants.  The fuel tank of an aircraft is generally placed in an empty volume of a box structure, particularly in the structure of the wings. To be able to contain the fuel, said volume must be sealed, and secondly, the materials constituting said box structure must be protected from any damage that could cause their contact with the fuel. This latter characteristic is particularly relevant in the case where the materials constituting the box structure are organic matrix composite materials, to which the fuel hydrocarbons act as solvents.
Selon l'art antérieur cette protection peut être obtenue par l'insertion d'une vessie dans le volume vide de la structure caisson utilisée comme réservoir. Cette solution est défavorable pour les applications aéronautiques car la vessie constitue une masse supplémentaire. De plus, la forme interne du volume vide, dictée essentiellement par des considérations structurales, peut être complexe et, tant l'adaptation de la forme de la vessie à ce volume, que l'introduction de ladite vessie dans ce volume sont délicates.  According to the prior art this protection can be obtained by inserting a bladder into the empty volume of the caisson structure used as a reservoir. This solution is unfavorable for aeronautical applications because the bladder constitutes an additional mass. In addition, the internal shape of the empty volume, dictated essentially by structural considerations, can be complex and, both the adaptation of the shape of the bladder to this volume, as the introduction of said bladder in this volume are delicate.
Une autre solution de l'art antérieur consiste à peindre les pièces structurales délimitant le volume vide de la structure caisson avec un primaire spécifique, résistant aux hydrocarbures. Cette solution technique impose une opération de peinture dans la gamme de fabrication et sa qualité de réalisation est dépendante du savoir-faire de l'opérateur.  Another solution of the prior art is to paint the structural parts defining the empty volume of the box structure with a specific primer, resistant to hydrocarbons. This technical solution imposes a painting operation in the manufacturing range and its quality of realization is dependent on the know-how of the operator.
Finalement, selon une troisième solution de l'art antérieur, la protection est réalisée en appliquant à l'intérieur du volume vide de la structure caisson assemblée, un mastic liquide à base de polythioéther. Cette opération, généralement réalisée au pinceau, est couramment désignée sous le terme de barattage, et s'avère être de mise en œuvre particulièrement pénible.  Finally, according to a third solution of the prior art, the protection is achieved by applying inside the empty volume of the assembled box structure, a liquid sealant based on polythioether. This operation, usually carried out with a brush, is commonly referred to as churning, and turns out to be particularly painful.
Le document WO 2007 045466 décrit un réservoir de carburant en matériau composite à matrice organique, ainsi que des procédés de fabrication d'un tel réservoir. Le réservoir de carburant décrit dans ce document de l'art antérieur est destiné à une motocyclette ou à une automobile et constitue une réservoir de faible volume. Ce document divulgue deux mode de réalisation d'un tel réservoir, le premier constant à mouler une enveloppe constituée d'un matériau thermoplastique sur laquelle des plis renforcés sont ensuite drappés. Le second mode consiste à d'abord réaliser une enveloppe constituée d'un matériau composite stratifié puis à recouvrir, après cuisson, l'intérieur de cette enveloppe d'un film thermoplastique par soufflage ou rotomoulage de ce film à l'intérieur du volume du réservoir ainsi constitué. Ces modes de réalisation sont totalement inadapté à la réalisation d'un réservoir destiné à un aéronef. WO 2007 045466 discloses a fuel tank of material organic matrix composite, as well as methods for making such a reservoir. The fuel tank described in this prior art document is intended for a motorcycle or automobile and constitutes a small volume reservoir. This document discloses two embodiments of such a reservoir, the first constant to mold an envelope made of a thermoplastic material on which reinforced plies are then draped. The second method consists in first producing an envelope made of a laminated composite material and then covering, after firing, the inside of this envelope with a thermoplastic film by blowing or rotomolding this film inside the volume of the reservoir thus constituted. These embodiments are totally unsuitable for the production of a tank intended for an aircraft.
L'invention vise à résoudre les inconvénients de l'art antérieur et concerne à cette fin un procédé pour la réalisation d'un élément de structure comprenant un panneau en matériau composite à renfort fibreux dans une matrice organique obtenu par drapage et cuisson, lequel panneau comprend une face susceptible d'être exposée au contact avec des hydrocarbures, ledit procédé comportant les étapes consistant à :  The invention aims at solving the drawbacks of the prior art and for this purpose concerns a method for producing a structural element comprising a panel made of composite material with fibrous reinforcement in an organic matrix obtained by draping and baking, which panel comprises a face liable to be exposed in contact with hydrocarbons, said process comprising the steps of:
a. draper les plis de fibres préimprégnées d'une résine ayant une première température de cuisson, T1 , de sorte à obtenir la stratification visée ; b. déposer sur la face exposée aux hydrocarbures, un pli constitué d'un film mince d'un polymère résistant aux hydrocarbures et à la température de cuisson T1 , dit film de protection ;  at. draping the fiber plies preimpregnated with a resin having a first baking temperature, T1, so as to obtain the desired stratification; b. depositing on the side exposed to hydrocarbons, a fold consisting of a thin film of a hydrocarbon resistant polymer and the firing temperature T1, said protective film;
c. réaliser la cuisson sous pression à la température T1 de l'ensemble de la stratification.  vs. carry out pressure cooking at the temperature T1 of the entire lamination.
Ainsi, la protection de la surface exposée est obtenue lors de la fabrication des éléments constituant la structure caisson au stade de la pièce élémentaire et l'application de cette protection ne modifie par le temps d'assemblage de la structure. Lors de l'application de la protection, les pièces sont parfaitement accessibles et la protection est assurée uniformément sur toute la surface recouverte par le film. La co- cuisson du film et de la pièce assure la cohésion du film sur la surface protégée. Le film étant mince, la masse ajoutée est faible.  Thus, the protection of the exposed surface is obtained during the manufacture of the elements constituting the box structure at the stage of the elementary part and the application of this protection does not change the assembly time of the structure. When applying the protection, the parts are perfectly accessible and the protection is provided uniformly over the entire surface covered by the film. The co-firing of the film and the part ensures the cohesion of the film on the protected surface. The film being thin, the added mass is small.
L'invention peut être mise en œuvre selon les modes de réalisation avantageux exposés ci-après, lesquels peuvent être considérés individuellement ou selon toute combinaison techniquement opérante. Selon un mode de réalisation avantageux, la matrice est constituée d'une résine thermodurcissable époxyde et le film de protection est constitué d'un polymère de polyétheréthercétone (PEEK) d'une épaisseur comprise entre 0,015 mm et 0,035 mm. The invention can be implemented according to the advantageous embodiments described below, which can be considered individually or in any technically operative combination. According to an advantageous embodiment, the matrix consists of an epoxy thermosetting resin and the protective film consists of a polyetheretherketone polymer (PEEK) with a thickness of between 0.015 mm and 0.035 mm.
Ainsi, les propriété du film PEEK n'étant pas affectées par la cuisson de la résine époxyde, ledit film étant par ailleurs parfaitement résistants aux hydrocarbures utilisés comme carburant d'aéronef, il n'ajoute qu'une masse de quelques dizaines de grammes par m2 de surface sur laquelle il est appliqué. Thus, since the properties of the PEEK film are not affected by the baking of the epoxy resin, said film being otherwise perfectly resistant to the hydrocarbons used as aircraft fuel, it adds only a mass of a few tens of grams per m 2 of surface on which it is applied.
Avantageusement, le film de protection déposé à l'étape b) du procédé objet de l'invention ne couvre pas la totalité de la face exposée aux hydrocarbures. Ainsi, le procédé objet de l'invention permet de conserver des zones non couvertes par le film de protection, notamment pour le collage ou l'assemblage avec d'autres pièces.  Advantageously, the protective film deposited in step b) of the method which is the subject of the invention does not cover the entire face exposed to hydrocarbons. Thus, the method that is the subject of the invention makes it possible to preserve areas that are not covered by the protective film, in particular for gluing or assembling with other parts.
Selon ce mode de réalisation l'étape b) du procédé objet de l'invention comprend les opérations consistant à :  According to this embodiment, step b) of the method which is the subject of the invention comprises the operations of:
b.i. découper le film de protection au contour visé ; b.ii. projeter l'emplacement des zones non couvertes par le film de protection ; b.iii. déposer le film sur la stratification en dehors des zones ainsi délimitées. Avantageusement une face du film de protection est traitée pour en améliorer la mouillabilité. Ainsi, l'adhésion du film à la résine, après cuisson de celle-ci est améliorée.  bi. cut the protective film to the desired contour; b.ii. project the location of areas not covered by the protective film; b.iii. deposit the film on the stratification outside the areas thus delimited. Advantageously one side of the protective film is treated to improve wettability. Thus, the adhesion of the film to the resin after firing thereof is improved.
Avantageusement, le film de protection comprend une couche d'un adhésif sensible à la pression, dit PSA, sur l'une de ses faces. Ainsi, l'application du film sur la stratification est facilitée, particulièrement lorsque ladite stratification n'est pas pégueuse. PSA étant l'acronyme de l'expression en langue anglaise « Pressure Sensitive Adhesive ».  Advantageously, the protective film comprises a layer of a pressure-sensitive adhesive, called PSA, on one of its faces. Thus, the application of the film to the lamination is facilitated, particularly when said lamination is not tacky. PSA is the acronym for the English expression "Pressure Sensitive Adhesive".
Selon un mode de réalisation particulier, le film de protection est déposé en plusieurs lés avec des recouvrements des bords desdits lés. Ainsi le procédé objet de l'invention est adapté à la couverture de pièces élémentaires de grande dimension tout en assurant l'étanchéité entre les lés de film de protection déposés.  According to a particular embodiment, the protective film is deposited in several layers with overlaps of the edges of said strips. Thus, the method which is the subject of the invention is suitable for covering large elementary parts while ensuring the seal between the deposited protective film strips.
Avantageusement le procédé objet de l'invention comprend entre les étapes b) et c) une étape consistant à :  Advantageously, the method which is the subject of the invention comprises, between steps b) and c), a step consisting of:
d. compacter la stratification et le film sous sac à vide. Ainsi la cohésion mécanique du film avec la stratification est assurée. d. compact the lamination and the vacuum bag film. Thus the mechanical cohesion of the film with the stratification is ensured.
L'invention concerne également un procédé pour la fabrication d'une structure en caisson comportant un volume apte à contenir du carburant lequel procédé comprend les étapes consistant à :  The invention also relates to a method for manufacturing a box structure having a volume adapted to contain fuel which method comprises the steps of:
i. obtenir une pluralité de pièces constituant la structure en caisson selon un mode de réalisation du procédé précédent ;  i. obtaining a plurality of parts constituting the box structure according to an embodiment of the preceding method;
ii. assembler lesdites pièces de sorte à constituer la structure ;  ii. assembling said parts so as to constitute the structure;
iii. parfaire l'étanchéité de la structure ainsi constituée au niveau des interfaces d'assemblage.  iii. perfect the tightness of the structure thus formed at the assembly interfaces.
Ainsi, les opérations pour la protection et l'étanchéité de la structure en caisson se limitent au traitement des interfaces d'assemblage.  Thus, the operations for the protection and sealing of the box structure are limited to the processing of assembly interfaces.
Selon un mode de réalisation particulier, l'étape ii) du procédé est réalisée par rivetage.  According to a particular embodiment, step ii) of the method is carried out by riveting.
Selon un mode de réalisation alternatif, l'étape ii) du procédé est réalisée par collage.  According to an alternative embodiment, step ii) of the process is carried out by gluing.
L'invention concerne également un aéronef comprenant une structure en caisson dont un volume vide est utilisé comme réservoir à carburant, ladite structure en caisson comportant un élément structural comprenant un panneau composite à renfort fibreux obtenu selon le procédé objet de l'invention. L'utilisation des matériaux composites pour la constitution de cette structure caisson associée au mode de protection de ces matériaux permet de réaliser un gain de masse en regard des solutions connues de l'art antérieur et de faciliter la fabrication d'une telle structure. Ainsi, l'aéronef objet de l'invention est avantageux tant en termes de coût de fabrication que de coût d'exploitation.  The invention also relates to an aircraft comprising a box structure of which an empty volume is used as a fuel tank, said box structure comprising a structural element comprising a composite panel with fiber reinforcement obtained according to the method which is the subject of the invention. The use of composite materials for the constitution of this box structure associated with the method of protection of these materials makes it possible to achieve a gain in mass compared to the known solutions of the prior art and to facilitate the manufacture of such a structure. Thus, the aircraft object of the invention is advantageous both in terms of manufacturing cost and operating cost.
L'invention est exposée ci-après selon ses modes de réalisation préférés, nullement limitatifs, et en référence aux figures 1 à 4, dans les quelles :  The invention is explained below according to its preferred embodiments, in no way limiting, and with reference to FIGS. 1 to 4, in which:
- la figure 1 est une vue partielle en coupe et en éclaté d'un exemple de réalisation d'une structure en caisson selon l'invention ;  - Figure 1 is a partial sectional view and exploded of an embodiment of a box structure according to the invention;
- la figure 2 représente selon la même vue que la figure 1 , la même structure caisson après assemblage ;  - Figure 2 shows in the same view as Figure 1, the same box structure after assembly;
- la figure 3 montre en perspective et en éclaté une des pièces élémentaires de la structure caisson des figures 1 et 2 au cours de la réalisation de ladite pièce élémentaire ; - Figure 3 shows in perspective and exploded one of the elementary parts of the box structure of Figures 1 and 2 during the production of said part elementary;
- et la figure 4 est un organigramme montrant les étapes du procédé selon un exemple de réalisation de l'invention.  and FIG. 4 is a flowchart showing the steps of the method according to an exemplary embodiment of the invention.
Figure 1 , selon un exemple de réalisation, la structure en caisson (100) objet de l'invention est constituée d'une pluralité de pièces élémentaires (1 10, 121 , 122) constituées d'un matériau composite à renfort fibreux. À titre d'exemple non limitatif, ledit matériau composite comprend des fibres de carbone dans une matrice en résine époxyde. Les pièces élémentaires sont assemblées le long d'interfaces d'assemblage (1 12, 1 13). Cet assemblage peut être réalisé par collage ou par co-cuisson. Alternativement ou conjointement, l'assemblage peut être réalisé par rivetage. Ces techniques d'assemblage sont connues de l'art antérieur et ne sont pas exposées plus avant. Le volume intérieur (150) de cette structure caisson est susceptible de contenir du carburant. Afin de protéger les pièces élémentaires (121 , 122, 1 10) du contact avec ce carburant, les faces exposées de celles-ci sont couvertes par un film de protection (130, 131 , 132) posé sur lesdites faces lors de la fabrication des pièces élémentaires (1 10, 121 , 122). Selon un mode de réalisation préféré, ce film de protection est constitué de polyéthertéhercétone ou PEEK. De tels films sont, par exemple, commercialisés sous la marque APTIV® par la société VICTREX®.  Figure 1, according to an exemplary embodiment, the box structure (100) object of the invention consists of a plurality of elementary parts (1 10, 121, 122) made of a composite material with fibrous reinforcement. By way of nonlimiting example, said composite material comprises carbon fibers in an epoxy resin matrix. The elementary parts are assembled along assembly interfaces (1 12, 1 13). This assembly can be achieved by gluing or co-cooking. Alternatively or jointly, the assembly can be made by riveting. These assembly techniques are known from the prior art and are not discussed further. The interior volume (150) of this box structure is likely to contain fuel. In order to protect the elementary parts (121, 122, 1 10) from contact with this fuel, the exposed faces thereof are covered by a protective film (130, 131, 132) placed on said faces during the manufacture of elementary pieces (1 10, 121, 122). According to a preferred embodiment, this protective film consists of polyetheretherketone or PEEK. Such films are, for example, marketed under the trademark APTIV® by VICTREX®.
Figure 2, après assemblage, les interstices subsistant entre les pièces élémentaires sont comblés par des cordons de mastic (212, 213) afin de parfaire l'étanchéité de l'ensemble. Le mastic utilisé est un mastic résistant aux hydrocarbures, par exemple un mastic à base de polythioéther distribué sous la dénomination PR par la société Le Joint Français®.  2, after assembly, the interstices remaining between the elementary parts are filled by cords of mastic (212, 213) to complete the seal of the assembly. The mastic used is a hydrocarbon-resistant mastic, for example a mastic based on polythioether distributed under the name PR by the company Le Joint Français®.
Figure 3, selon un exemple de réalisation d'une pièce élémentaire (1 10) de la structure caisson objet de l'invention, ladite pièce est réalisée par drapage de plis de fibres préimprégnées. Selon un mode de réalisation particulier, le drapage peut être partiellement réalisé autour d'un noyau (310) par exemple autour d'une plaque en nid d'abeille. Ce drapage peut être automatique ou manuel. Le film protecteur est posé sur la zone exposée au carburant de la préforme de la pièce (1 10), par exemple sous la forme d'une pluralité (331 , 332) de lés de film PEEK. Chaque lé (331 , 332) comprend une zone de recouvrement avec le lé qui lui est juxtaposé, de sorte que la jonction entre deux lés soit étanche. Les zones (312, 313) formant interface avec les autres pièces élémentaires pour l'assemblage de la structure en caisson, ne sont pas couvertes par le film de protection (331 , 332). Le film de protection est ici représenté selon une découpe rectiligne. En pratique le contour du film peut être plus complexe de sorte à ménager des épargnes (331 , 332) de forme également plus complexe. Dans ce cas, les lés (331 , 332) de film de protection sont, préalablement à leur pose, découpés au contour désiré. L'opération de pose des films de protection est réalisée manuellement. Elle est grandement facilitée par le fait que la pièce élémentaire se trouve à plat, accessible de tous les côtés durant cette opération. Le film de protection peut être également découpé en plusieurs lés de sorte à faciliter la manipulation de ceux-ci. Pour assister l'opérateur durant la pose dudit film de protection, le contour du lé à déposer sur la préforme peut être projeté par laser sur ladite préforme selon une méthode connue de l'art antérieur pour le drapage manuel. Selon la dimension de la pièce élémentaire, les lés de film de protection sont stabilisés sur la structure lors de la pose, grâce à la pégosité des plis préalablement drapés. Lorsque les dimensions de la pièce sont importantes les lés de film de protection peuvent être appliqués sur la préforme par un compactage sous sac à vide juste avant la cuisson de ladite préforme. Le film protecteur est avantageusement traité sur sa face en contact avec la résine constituant la matrice de la pièce, par une méthode visant à en accroître la mouillabilité de sorte à améliorer l'adhésion du film à la pièce sur toute sa surface. Un tel traitement consiste à augmenter l'énergie libre de surface du film de sorte que celle-ci soit supérieure à celle de la résine liquide et que ladite résine mouille correctement la surface du film au cours de l'opération de cuisson. Dans le cas d'un film PEEK ce traitement, réalisé par plasma, par UV ou par ozone, sans que cette liste ne soit exhaustive, permet de faire croître l'énergie libre superficielle de la face ainsi traitée jusqu'à une valeur comprise entre 55 et 60 Joules. m"1. Dans le cas où plusieurs lés sont posés avec recouvrement des bords des lés juxtaposés, le traitement d'amélioration de la mouillabilité est réalisé sur les deux faces du film de protection. Figure 3, according to an exemplary embodiment of an elementary part (1 10) of the box structure object of the invention, said piece is made by draping folds of prepreg fibers. According to a particular embodiment, the draping may be partially performed around a core (310) for example around a honeycomb plate. This draping can be automatic or manual. The protective film is placed on the fuel-exposed area of the preform of the workpiece (1 10), for example in the form of a plurality (331, 332) of PEEK film webs. Each strip (331, 332) comprises a zone of overlap with the side which is juxtaposed to it, so that the junction between two strips is sealed. Areas (312, 313) interfacing with other rooms elements for the assembly of the box structure, are not covered by the protective film (331, 332). The protective film is here represented in a rectilinear cut. In practice the contour of the film may be more complex so as to save savings (331, 332) of a more complex form. In this case, the strips (331, 332) of the protective film are, before being laid, cut to the desired contour. The operation of laying protective films is performed manually. It is greatly facilitated by the fact that the elementary piece is flat, accessible from all sides during this operation. The protective film can also be cut into several strips so as to facilitate handling thereof. To assist the operator during the laying of said protective film, the outline of the lé to be deposited on the preform can be projected by laser on said preform according to a known method of the prior art for manual draping. Depending on the size of the elementary part, the protective film strips are stabilized on the structure during installation, thanks to the tackiness of the folds previously draped. When the dimensions of the part are important, the protective film strips may be applied to the preform by compacting under a vacuum bag just before said preform is fired. The protective film is advantageously treated on its face in contact with the resin constituting the matrix of the part, by a method to increase the wettability so as to improve the adhesion of the film to the part over its entire surface. Such a treatment consists in increasing the free surface energy of the film so that it is greater than that of the liquid resin and that said resin wets the surface of the film correctly during the cooking operation. In the case of a PEEK film, this treatment, carried out by plasma, UV or ozone, without this list being exhaustive, makes it possible to increase the free surface energy of the treated surface to a value between 55 and 60 Joules. m "1. In the case where several strips are placed with overlap of the edges of the juxtaposed, treatment to improve the wettability is formed on both sides of the protective film.
Dans le cas où les plis de fibres drapés sont faiblement préimprégnés, par exemple avec un taux de résine inférieur à 5 %, courament désignées par « fibres sèches », les lés de film de protection peuvent être enduits sur toute ou partie de leur face en contact avec la stratification, par un adhésif sensible à la pression, ou PSA, par exemple avec un adhésif à base de silicones, ceci afin de faciliter leur pose. Ainsi le procédé objet de l'invention est également adapté à la réalisation de pièces à partir de fibres sèches, notamment par injection ou infusion de résine. In the case where the folds of draped fibers are weakly pre-impregnated, for example with a resin content of less than 5%, commonly referred to as "dry fibers", the protective film strips may be coated on all or part of their face. contact with the lamination, with a pressure-sensitive adhesive, or PSA, for example with a silicone-based adhesive, in order to facilitate their installation. So the The method of the invention is also suitable for producing parts from dry fibers, in particular by injection or infusion of resin.
Figure 4, le procédé objet de l'invention comprend une première série d'étapes correspondant à la réalisation des pièces élémentaires. Ainsi, pour chaque pièce élémentaire, une première étape (410) de drapage permet de constituer la préforme de la pièce. Au cours d'une étape de préparation (420) le film de protection est découpé au contour visé pour recouvrir tout ou partie de la surface de la pièce exposée aux hydrocarbures. Le lé de film ainsi découpé est déposé sur la préforme au cours d'une étape (430) de dépose dudit lé. Ce lé est maintenu sur la préforme par la pégosité des plis préimprégnés précédemment drapés, ou par la présence d'un adhésif de type PSA sur toute ou partie de la surface du lé en contact avec la préforme. Les étapes précédentes (420, 430) sont répétées pour différents lés jusqu'à recouvrir toute la surface exposée aux hydrocarbures de la pièce . Lorsque la dite surface exposée est entièrement couverte, la préforme est ensachée, au cours d'une étape (440) d'ensachage, et l'ensemble est compacté, au cours d'une étape de compactage (450) en tirant au vide l'ensemble ainsi ensaché.  Figure 4, the method of the invention comprises a first series of steps corresponding to the realization of the elementary parts. Thus, for each elementary piece, a first step (410) of draping makes it possible to form the preform of the part. During a preparation step (420) the protective film is cut to the target contour to cover all or part of the surface of the part exposed to hydrocarbons. The film strip thus cut is deposited on the preform during a step (430) of removing said strip. This lé is maintained on the preform by the tackiness prepreg folds previously draped, or by the presence of a PSA-type adhesive on all or part of the surface of the web in contact with the preform. The previous steps (420,430) are repeated for different threads to cover the entire hydrocarbon exposed surface of the workpiece. When said exposed surface is completely covered, the preform is bagged, during a bagging step (440), and the whole is compacted, during a compaction step (450) by drawing vacuum. together and bagged.
La préforme est ensuite dirigée vers un autoclave pour une étape (460) de cuisson. Selon l'exemple de réalisation où la stratification de la préforme est constituée de fibres de carbone dans une résine époxyde, la cuisson est réalisée à une température T1 de l'ordre de 180 °C. Le film de protection constitué de PEEK résiste parfaitement à cette température T1 sans subir de dégradation, c'est à dire sans fusion et sans perte d'étanchéité du film. Selon un mode de réalisation particulier, la cuisson peut être partielle de sorte à conserver une possibilité d'assemblage par co-cuisson.  The preform is then directed to an autoclave for a cooking step (460). According to the embodiment where the lamination of the preform consists of carbon fibers in an epoxy resin, the firing is carried out at a temperature T1 of the order of 180 ° C. The protective film consisting of PEEK withstands perfectly this temperature T1 without undergoing degradation, that is to say without melting and without leakage of the film. According to a particular embodiment, the cooking may be partial so as to maintain a possibility of assembly by co-cooking.
Les pièces élémentaires étant réalisées et protégées par un film protecteur sur leurs faces exposées au carburant, celles-ci sont assemblées au cours d'une étape d'assemblage (470). Cet assemblage peut être réalisé par collage, rivetage ou co- cuisson selon des procédés connus de l'art antérieur. Au cours d'une étape (480) de parachèvement, l'étanchéité des interstices entre les pièces ainsi assemblées est réalisée par la pose de cordons de mastic d'étanchéité.  The elementary parts being made and protected by a protective film on their faces exposed to the fuel, they are assembled during an assembly step (470). This assembly can be achieved by gluing, riveting or co-cooking according to methods known from the prior art. During a step (480) of completion, the tightness of the interstices between the parts thus assembled is achieved by laying cords sealing mastic.
La description ci-avant et les exemples de réalisation montrent que l'invention atteint les objectifs visés, en particulier elle permet d'obtenir une structure caisson constituée d'un matériau composite à renfort fibreux, ladite structure caisson comportant un volume vide apte à contenir du carburant, laquelle structure est obtenue de manière économique et reproductible, avec une faible masse ajoutée pour obtenir l'étanchéité dudit volume vide et la protection des matériaux structuraux vis-à-vis du contact avec les hydrocarbures. The above description and the exemplary embodiments show that the invention achieves the desired objectives, in particular it makes it possible to obtain a box structure made of a composite material with a fibrous reinforcement, said box structure comprising an empty volume capable of containing fuel, which structure is obtained economically and reproducibly, with a low added mass to obtain the seal of said empty volume and the protection of the structural materials vis-à-vis the contact with the hydrocarbons.

Claims

REVENDICATIONS
Procédé pour la réalisation d'un élément de structure comprenant un panneau (1 10, 121 , 122) en matériau composite à renfort fibreux dans une matrice organique obtenu par drapage et cuisson, lequel panneau comprend une face susceptible d'être exposée au contact avec des hydrocarbures, caractérisé en ce qu'il comporte les étapes consistant à : a. draper (410) les plis de fibres préimprégnées d'une résine ayant une première température de cuisson, T1 , de sorte à obtenir la stratification visée ; Process for the production of a structural element comprising a panel (1, 10, 121, 122) made of composite material with fibrous reinforcement in an organic matrix obtained by draping and baking, which panel comprises a face that can be exposed to contact with hydrocarbons, characterized in that it comprises the steps of: a. draping (410) the fiber plies preimpregnated with a resin having a first baking temperature, T1, so as to obtain the desired stratification;
b. déposer (430) sur la face exposée aux hydrocarbures, un pli constitué d'un film mince (130, 131 , 132) d'un polymère résistant aux hydrocarbures et à la température de cuisson T1 , dit film de protection (130, 131 , 132); b. depositing (430) on the hydrocarbon-exposed face, a fold consisting of a thin film (130, 131, 132) of a hydrocarbon resistant polymer and the firing temperature T1, said protective film (130, 131, 132);
c. réaliser la cuisson (460) sous pression à la température T1 de l'ensemble de la stratification. vs. cooking (460) under pressure at the temperature T1 of all the lamination.
Procédé selon la revendication 1 , caractérisé en ce que la matrice est constituée d'une résine thermodurcissable époxyde et le film (130, 131 , 132) de protection est constitué d'un polymère de polyétheréthercétone (PEEK) d'une épaisseur comprise entre 0,015 mm et 0,035 mm. Process according to Claim 1, characterized in that the matrix consists of an epoxy thermosetting resin and the protective film (130, 131, 132) consists of a polyetheretherketone polymer (PEEK) with a thickness of 0.015 mm and 0.035 mm.
Procédé selon la revendication 1 , caractérisé en ce que le film de protection (130, 131 , 132) déposé à l'étape b) ne couvre pas la totalité de la face exposée aux hydrocarbures. Process according to claim 1, characterized in that the protective film (130, 131, 132) deposited in step b) does not cover the whole of the oil-exposed face.
Procédé selon la revendication 3, caractérisé en ce que l'étape b) comprend les opérations consistant à : Method according to claim 3, characterized in that step b) comprises the steps of:
b.i. découper (420) le film de protection au contour visé ; bi. cutting (420) the protective film to the target contour;
b.ii. projeter l'emplacement des zones non couvertes par le film de protection ; b.ii. project the location of areas not covered by the protective film;
b.iii. déposer (430) le film sur la stratification en dehors des zones ainsi délimitées. Procédé selon la revendication 1 , caractérisé en ce qu'une face du film de protection (130, 131 , 132, 331 , 332) est traitée pour en améliorer la mouillabilité. b.iii. deposit (430) the film on the lamination outside the zones thus delimited. Process according to claim 1, characterized in that one side of the protective film (130, 131, 132, 331, 332) is treated to improve the wettability thereof.
Procédé selon la revendication 1 , caractérisé en ce que le film de protection (130, 131 , 132, 331 , 332) comprend une couche d'un adhésif sensible à la pression, dit PSA, sur l'une de ses faces. Process according to claim 1, characterized in that the protective film (130, 131, 132, 331, 332) comprises a layer of a pressure-sensitive adhesive, called PSA, on one of its faces.
Procédé selon la revendication 1 , caractérisé en ce que le film de protection (130, 131 , 132) est déposé en plusieurs lés (331 , 332) avec des recouvrements des bords desdits lés. A method according to claim 1, characterized in that the protective film (130, 131, 132) is deposited in several strips (331, 332) with overlaps of the edges of said strips.
Procédé selon la revendication 1 , caractérisé en ce qu'il comprend entre les étapes b) et c) une étape consistant à : Process according to Claim 1, characterized in that it comprises, between steps b) and c), a step consisting of:
d. compacter (450) la stratification et le film sous sac à vide. d. compacting (450) the lamination and the vacuum bag film.
Procédé pour la fabrication d'une structure en caisson (100) comportant un volume (150) apte à contenir du carburant caractérisé en ce qu'il comprend les étapes consistant à : A method for manufacturing a box structure (100) having a volume (150) adapted to contain fuel characterized in that it comprises the steps of:
i. obtenir une pluralité de pièces constituant la structure en caisson selon le procédé de la revendication 4 ; i. obtaining a plurality of parts constituting the box structure according to the method of claim 4;
ii. assembler (470) lesdites pièces de sorte à constituer la structure ; iii. parfaire (480) l'étanchéité de la structure ainsi constituée au niveau des interfaces d'assemblage. ii. assembling (470) said parts so as to constitute the structure; iii. perfect (480) the sealing of the structure thus formed at the assembly interfaces.
Procédé selon la revendication 9, caractérisé en ce que l'étape ii) est réalisée par rivetage. Method according to claim 9, characterized in that step ii) is performed by riveting.
Procédé selon la revendication 9, caractérisé en ce que l'étape ii) est réalisée par collage. Process according to Claim 9, characterized in that step ii) is carried out by gluing.
Aéronef comprenant une structure en caisson (100) dont un volume vide (150) est utilisé comme réservoir à carburant, caractérisé en ce que ladite structure en caisson comporte un élément structural (1 10, 121 , 122) comprenant un panneau composite à renfort fibreux obtenu selon le procédé de la revendication 1 . Aircraft comprising a box structure (100) including an empty volume (150) is used as a fuel tank, characterized in that said box structure comprises a structural element (1 10, 121, 122) comprising a fibrous reinforcement composite panel obtained according to the method of claim 1.
EP12779065.7A 2011-10-28 2012-10-29 Method for sealing a fuel tank Withdrawn EP2771169A2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP18195582.4A EP3446863B1 (en) 2011-10-28 2012-10-29 Method for sealing a fuel tank

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR1159817A FR2981880B1 (en) 2011-10-28 2011-10-28 PROCESS FOR SEALING A FUEL TANK
PCT/EP2012/071383 WO2013060890A2 (en) 2011-10-28 2012-10-29 Method for sealing a fuel tank

Related Child Applications (1)

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EP18195582.4A Division EP3446863B1 (en) 2011-10-28 2012-10-29 Method for sealing a fuel tank

Publications (1)

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EP2771169A2 true EP2771169A2 (en) 2014-09-03

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EP18195582.4A Active EP3446863B1 (en) 2011-10-28 2012-10-29 Method for sealing a fuel tank
EP12779065.7A Withdrawn EP2771169A2 (en) 2011-10-28 2012-10-29 Method for sealing a fuel tank

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US (1) US9475586B2 (en)
EP (2) EP3446863B1 (en)
BR (1) BR112014010170B1 (en)
CA (1) CA2849707A1 (en)
ES (1) ES2785027T3 (en)
FR (1) FR2981880B1 (en)
WO (1) WO2013060890A2 (en)

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Also Published As

Publication number Publication date
CA2849707A1 (en) 2013-05-02
US20140239122A1 (en) 2014-08-28
WO2013060890A3 (en) 2013-08-15
EP3446863A1 (en) 2019-02-27
BR112014010170A2 (en) 2017-04-25
FR2981880B1 (en) 2014-09-19
EP3446863B1 (en) 2019-12-04
US9475586B2 (en) 2016-10-25
WO2013060890A2 (en) 2013-05-02
ES2785027T3 (en) 2020-10-05
BR112014010170B1 (en) 2020-04-07
FR2981880A1 (en) 2013-05-03

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