EP2936140A1 - Reconfigurable device for checking a composite structure using ultrasound - Google Patents

Reconfigurable device for checking a composite structure using ultrasound

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Publication number
EP2936140A1
EP2936140A1 EP13811547.2A EP13811547A EP2936140A1 EP 2936140 A1 EP2936140 A1 EP 2936140A1 EP 13811547 A EP13811547 A EP 13811547A EP 2936140 A1 EP2936140 A1 EP 2936140A1
Authority
EP
European Patent Office
Prior art keywords
layer
film
electrode
piezoelectric material
face
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Withdrawn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
EP13811547.2A
Other languages
German (de)
French (fr)
Inventor
Stéphane AUFFRAY
Hubert Voillaume
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.)
Airbus SAS
Original Assignee
European Aeronautic Defence and Space Company EADS France
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 European Aeronautic Defence and Space Company EADS France filed Critical European Aeronautic Defence and Space Company EADS France
Publication of EP2936140A1 publication Critical patent/EP2936140A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
    • G01N29/22—Details, e.g. general constructional or apparatus details
    • G01N29/223—Supports, positioning or alignment in fixed situation
    • 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
    • B29C70/44—Shaping or impregnating by compression not applied for producing articles of definite length, i.e. discrete articles using isostatic pressure, e.g. pressure difference-moulding, vacuum bag-moulding, autoclave-moulding or expanding rubber-moulding
    • 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
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
    • G01N29/22—Details, e.g. general constructional or apparatus details
    • G01N29/24—Probes
    • G01N29/2437—Piezoelectric probes
    • G01N29/245—Ceramic probes, e.g. lead zirconate titanate [PZT] probes
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2291/00—Indexing codes associated with group G01N29/00
    • G01N2291/02—Indexing codes associated with the analysed material
    • G01N2291/023—Solids
    • G01N2291/0231—Composite or layered materials
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2291/00—Indexing codes associated with group G01N29/00
    • G01N2291/02—Indexing codes associated with the analysed material
    • G01N2291/025—Change of phase or condition
    • G01N2291/0251—Solidification, icing, curing composites, polymerisation
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2291/00—Indexing codes associated with group G01N29/00
    • G01N2291/04—Wave modes and trajectories
    • G01N2291/044—Internal reflections (echoes), e.g. on walls or defects
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2291/00—Indexing codes associated with group G01N29/00
    • G01N2291/10—Number of transducers
    • G01N2291/106—Number of transducers one or more transducer arrays

Definitions

  • the invention relates to the general field of instrumentation means for monitoring the manufacturing quality of composite material structures throughout the manufacturing process. It relates in particular to the means implementing sensors, transducers, ultrasound to perform this monitoring.
  • these means are generally integrated with the manufacturing tools themselves so that the transducers used generally occupy fixed, predetermined positions with respect to the surface of the structure being manufactured.
  • These sensors are permanently placed on the tools and molds used for manufacturing. They are generally glued on the elements of these tools in contact with the structure during manufacture or, alternatively, inserted in these same elements which have then undergone machining allowing them to integrate these sensors.
  • LRI latitude and low-latency
  • An object of the invention is to propose a solution for having a measuring means comprising a plurality of ultrasonic sensors, intended to perform ultrasonic measurements on composite material parts throughout the manufacturing process of these parts, the ultrasonic sensors being positioned at the surface of the analyzed part, this means making it possible to simply and inexpensively carry out measurements with different sensor arrangements.
  • Another object of the invention is to propose an ultrasonic measurement means which, while cooperating with the manufacturing means of the composite material parts which it is desired to control throughout the manufacturing process, is distinct from these means. .
  • an object of the invention is to find a solution to have an instrumentation easily reconfigurable and editable to optimize the ultrasonic measurements themselves to optimize the manufacturing process.
  • the subject of the invention is a device for controlling a composite material structure during its manufacture, said structure being produced in a space limited by the internal face of a first form and by the internal face of a second form, said device comprising a plurality of ultrasonic sensors arranged in the vicinity of the structure so that each ultrasonic sensor can emit an ultrasonic wave inside the structure and pick up the echo returned by this structure.
  • the device comprises a layer of piezoelectric material whose inner face is disposed on the outer face of the second form and a film of flexible electrical insulating material arranged to be pressed against the outer face of the layer of piezoelectric material.
  • Said film of flexible material comprises on its face in contact with the layer of piezoelectric material a plurality of electrodes, each electrode can be excited separately by a control signal transmitted by a conductor.
  • the conductive surface of each of the electrodes is arranged to be in contact with the surface of the layer of piezoelectric material so that each electrode forms with the zone of the layer of piezoelectric material, opposite which it is placed, a sensor separate ultrasound.
  • the device according to the invention may furthermore have additional characteristics.
  • the layer of piezoelectric material is directly formed on the outer face of the second form by implementing a sol-gel type process.
  • the electrical insulating film of flexible material is made of a polyimide-type polymer material.
  • the electrodes are formed by conductive pads disposed on the surface, on the face of said film in contact with the layer of piezoelectric material, each electrode being electrically powered by a conductive element constituted by a conductive track disposed either on the opposite side of the film is in the thickness of the film.
  • the conductive tracks supplying the different electrodes are provided at their end with a connector for applying an excitation voltage to each electrode.
  • each electrode is constituted by a single conductive pad whose dimensions are defined so that the ultrasonic sensor formed by this electrode and the layer of piezoelectric material emits a substantially flat ultrasound wave.
  • each electrode is constituted by a conductive pad formed of a plurality of elementary pellets whose dimensions are defined so that the ultrasonic sensor formed by an elementary pellet and the layer of material piezoelectric emits a substantially spherical or cylindrical ultrasonic wave; the elementary pellets being configured so that they can be ordered separately.
  • the elementary pellets are arranged relative to each other so that they can be excited so as to constitute a single ultrasonic sensor.
  • the excitation voltage is applied between said electrode and a common ground constituted by the second form.
  • the layer of piezoelectric material deposited on the outer face of the second form has a thickness e 2 of the order of several tens of microns.
  • the film of flexible material has a thickness ⁇ of the order of a few hundred microns.
  • the invention also relates to a tool for manufacturing a composite material structure implementing the LRI method, said tooling comprising a first element, or mold, and a second element, or "caul plate” vis-à-vis screw of the first element, the realized structure being placed between the inner faces of these two elements.
  • the tooling comprises an ultrasound control device according to the invention, the layer of piezoelectric material is formed on the outer face of the "flat caul", the film of flexible material is in turn pressed against said layer.
  • FIG. 2 is a schematic illustration of an ultrasonic testing device for the manufacture of a composite structure according to the invention, in the context of a manufacturing process LRI;
  • FIG. 3 is a partial schematic view of a tool for manufacturing an LRI process structure incorporating the device according to the invention
  • FIG. 4 a schematic illustration of an embodiment of the device according to the invention.
  • FIG. 5 an illustration of the operating principle of the device in the embodiment of FIG. 4;
  • FIG. 6, a schematic illustration of another embodiment of the device according to the invention
  • FIG. 7, an illustration of the principle of operation of the device in the embodiment of FIG. 6.
  • the device according to the invention is presented in the following description through its application in the context of a tool for manufacturing structures made of composite material implementing the LRI process (acronym for the name Anglo-Saxon "Liquid Resin Injection”).
  • LRI process acronym for the name Anglo-Saxon "Liquid Resin Injection”
  • the device according to the invention can be implemented and integrated into any type of tool for manufacturing structures in composite material, provided that these tools comprise the elements with which the device according to the invention cooperates.
  • FIG. 1 very schematically shows a device for ultrasonic testing of the manufacture of a composite structure according to the prior art, as part of a tool for manufacturing structures made of composite material implementing the LRI process.
  • this manufacturing tool comprises in particular an element 12, called mold, in which is injected the resin constituting the composite material structure 1 1 to be manufactured and an element 13 called “caul plate” or “cover plate ", which ensures the calibration in thickness and flatness of the structure 1 1 to be injected, arranged so that the structure being manufactured is placed between the mold 12 and the" caul plate "13.
  • This tooling also comprises at least one membrane 14, a flexible wall, arranged to delimit, with the mold 12, a space 15 surrounding both the structure 1 1 and the "caul plate” 13.
  • This membrane 14 is moreover configured so that it is possible to evacuate in the space 15 so that, the membrane enclosing the "flat caul” 13 and the structure 1 1, they are pressed against each other and against the mold 12.
  • the ultrasound control device integrated into this manufacturing tool is constituted by a number of ultrasonic sensors 16 arranged on the "flat caul", the active surface of the sensors 16 being placed on the surface of the "flat caul", opposite the surface of the structure 1 1, so as to propagate an ultrasonic wave through it.
  • the number and arrangement of the sensors 16 are a function of the dimensions of the structure 1 1 made and the distribution of the areas of the structure 1 1 that it is desired to analyze. Thus, if it is desired, for example, to analyze the structure 11 made uniformly, the ultrasonic sensors 16 are arranged in a regular manner facing the surface of the structure 11.
  • the sensors 16 are generally integrated directly in the "flat caul" 13, as illustrated in FIG.
  • This type of assembly makes it possible, because of the entrenchment of the sensors 16 in the "flat caul" 13, to ensure the correct positioning of the active faces of the sensors 16 vis-à-vis the surface of the structure 1 1 in the course of manufacture, and to simplify the maintenance in place of these sensors.
  • the ultrasonic sensors 16 used may each consist of a single element configured to transmit or receive an ultrasonic wave or a transmitter element 16 and of a receiver element 16r.
  • the sensors 16 are implanted in the only "flat caul” 13, while in the second case, illustrated in FIG. 1, the emitter element 16e is implanted in the "flat caul” 13 and the receiving element 16r in the mold 12, the active face of the receiving elements 16r then being directed towards the surface of the structure 1 1.
  • such implantation of sensors inside the manufacturing tool has the main advantage of making the installation of these sensors simple and permanent. Thus if one wishes to manufacture a series of identical structures 1 1, it is not necessary to deposit the sensors 16 to extract a structure at the end. of manufacture as it is not necessary to proceed to a new assembly of the sensors to start the manufacture of the following structure.
  • FIG. 2 presents a general schematic view of the ultrasound control device according to the invention, presented in a hardware configuration similar to that of the device of FIG. 1, known from the prior art.
  • the configuration presented here which corresponds to a reflection analysis, can easily be adapted to a transmission analysis.
  • the device according to the invention comprises two distinct cooperating elements, a piezoelectric ceramic layer 22 and a film of flexible material 21.
  • the piezoelectric ceramic layer 22 is a thin layer disposed on the outer face of the "flat caul” 13, that is to say the face opposite to the face in contact with the surface of the structure 1 1, which covers the entire the "caul plate”, or at least the entire surface of the "caul plate” located opposite the structure 1 1 to control.
  • the layer 22 of piezoelectric ceramic is made by a sol-gel type process, from a substrate deposited in the liquid or viscous phase on the outer surface of the "flat caul” , by "piezospray” technique for example, and hardened.
  • any method known to those skilled in the art for depositing on the surface of the "flat caul” a thin layer of piezoelectric material may alternatively be used to make the layer 22.
  • the film 21 of flexible material is, for its part, configured to be pressed against the outer surface of the piezoelectric ceramic layer 22, ie the face opposite to the face in contact with the surface of the flat caul "13.
  • this film As shown in the detailed view of FIG. 3, this film
  • the film 21 comprises a plurality of electrodes 31 of small thickness, arranged on the surface.
  • the face 33 of said film 21 which carries the electrodes 31 is intended to be pressed against the outer face of the layer 22 of piezoelectric material.
  • the film 21 further comprises a set of electrical conductors 32, which open out of the film by appropriate connectors and which make it possible to apply an electrical signal to each of the electrodes 31.
  • the film 21 may be made of any suitable flexible electrical insulating material, in particular having the required temperature and pressure resistance characteristics, the temperature and pressure conditions being those imposed by the manufacturing method of the structure 1 1.
  • the film 21 is a film of polymeric material of the polyimide group, for example a Kapton® film.
  • electrodes 31 and the conductors 32 are preferably made, in the manner of a printed circuit, in the form of pellets and tracks of conductive material, pellets and metal tracks for example.
  • the pellets forming the electrodes 31 are deposited on the surface, on those of the faces of the flexible film 21 intended to be put in contact with the layer 22 of piezoelectric material.
  • the conductive tracks 32 are implanted on the other side or, as illustrated in FIG. 3, in the thickness of the film, so as not to come into contact with the layer of piezoelectric material 22.
  • the electrodes-conductive tracks assembly is also realized and integrated into the flexible film by any method of producing flexible printed circuit boards, known to those skilled in the art.
  • the layer 22 of piezoelectric material deposited on the "flat caul" has a thickness e 2 of the order of a few tens of microns, typically of the order of 70 ⁇ , while the film 21 of flexible material has a thickness ⁇ of the order of a few hundred microns, typically of the order of 200 ⁇ .
  • the electrodes 31 and the conductive tracks 32 implanted on the film 21 have a thickness of about ten microns to several tens of microns. It should also be noted that the thickness and the nature of the film of piezoelectric material determines the resonance frequency of the layer 22.
  • the assembly consisting of the layer of piezoelectric material deposited on the caul plate "and the electrodes 31 disposed on the surface of the film of flexible material 21 form a plurality of ultrasonic sensors disposed on the surface of the" caul plate "facing the structure 1 1 to be analyzed, the distribution of ultrasonic sensors thus formed being simply defined by the arrangement of the electrodes on the surface of the flexible film.
  • each of the electrodes When excited by a signal, an electrical voltage, each of the electrodes forms, with the zone of the layer of piezoelectric material situated between it and the surface of the "flat caul", a piezoelectric transducer capable of emitting a wave ultrasound through the structure 1 1 and capture the echo produced by crossing this signal through the structure 1 1.
  • a set of ultrasonic sensors whose operation is identical, in principle, to that of the individual sensors 16 shown in FIG.
  • keeping the film 21 in contact with the piezoelectric layer 22 can advantageously be realized, incidentally, by the depression introduced into the space 15 delimited by the membrane 14 which contains the structure 1 1 during manufacture, and the "flat caul" 13 on which is deposited the layer of piezoelectric material 22 and the flexible film 21 on which the electrodes 31 are arranged.
  • the structure described in the foregoing text advantageously makes it possible to produce a device comprising a plurality of ultrasonic sensors, acoustic transducers, having functionalities similar to that of the ultrasonic sensors generally used, while at the same time having a greater ease of installation and use. 'use.
  • the sensors are integrated into the structure of the "flat caul” 13 and possibly of the mold 12.
  • the modification of the number and distribution of the sensors on the surface of the part to be controlled requires modifying or replacing the "caul plate" 13 and possibly the mold 12 so as to accommodate the sensors according to the new desired arrangement.
  • the layer of piezoelectric material deposited on the surface of the "flat caul” is a uniform layer and where the arrangement of the sensors is defined simply by the arrangement of the pellets conductive forming the electrodes 31 on the surface of the flexible film 21, change the arrangement and the number of sensors advantageously becomes simple and requires only the replacement of the flexible film 21.
  • This provides a control device easily reconfigurable simply by replacing or repositioning the flexible film 21, replacing the existing flexible film with another film having a different electrode arrangement with a cost advantageously less than the costs generated by the modification or replacing the "flat caul" 13 and possibly the mold 12.
  • FIGS. 4 to 7 show another advantage that the use of the device according to the invention has, which advantage is due to the variety of sensor configurations that can be implemented because of the structure itself of the device according to the invention.
  • each sensor of the device according to the invention consists of the corresponding electrode disposed on the flexible film 21 and the area of the layer 22 of piezoelectric material situated opposite this electrode.
  • the characteristics of each of the sensors of the device according to the invention can be defined separately by simply playing on the shape of the electrodes 31 disposed on the flexible film 21, each electrode being able to have a shape and dimensions of its own.
  • FIG. 4 shows a general plane view of a first type of electrode that can be implemented by the device according to the invention.
  • FIG 4 it is an electrode consisting of a single conductive pad 41 whose dimensions, length and width or diameter according to the shape of the electrode, are defined to emit in the Structure 1 1 analyzed a substantially flat wave having, for the acoustic frequency emitted, sufficient power to traverse the structure, while maintaining a sufficient analysis resolution.
  • the frequency determined by the characteristics of the piezoelectric coating for example, pellets having the shape of 5 mm squares will be chosen.
  • Such a pellet is excited by the application of a suitable voltage via a conductive track 42 externally connected to a voltage generator, a track which travels for example in the thickness of the film 21.
  • the device according to the invention then behaves, as illustrated in FIG. 5, in a manner similar to known ultrasonic testing devices comprising unitary sensors integrated into the manufacturing tool, while nevertheless retaining its advantageous features in terms of implementation and interchangeability.
  • Figure 6 shows a general view of a second type of electrode 61 that can be implemented by the device according to the invention in a more sophisticated embodiment.
  • the electrode shown in FIG. 6 consists of a plurality of elementary electrodes 62 grouped together for form an assembly having a particular arrangement, a matrix arrangement for example in the case of Figure 6.
  • each of the elementary electrodes 62 is configured so as to be able to excite independently by the application of a suitable voltage via a conductive track 63 connected externally to a voltage generator.
  • each elementary electrode produces, when excited, a substantially spherical or cylindrical wave. In this way, depending on the voltage applied to each of the elementary electrodes and the respective excitation instants of the different electrodes, it is possible to emit a sound wave having particular characteristics.
  • Each electrode 61 of the device then makes it possible advantageously to constitute a multi-element ultrasonic sensor whose acoustic characteristics in terms of precision and resolution can be substantially different from that of a traditional acoustic sensor such as those which equip the devices. known test.
  • FIG. 7 shows, by way of example, a particular application for which the elementary electrodes 62 forming the same electrode 61 are excited so as to each emit an elementary acoustic wave propagating through the structure 11.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Composite Materials (AREA)
  • Mechanical Engineering (AREA)
  • Immunology (AREA)
  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Pathology (AREA)
  • Ceramic Engineering (AREA)
  • Ultra Sonic Daignosis Equipment (AREA)
  • Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
  • Transducers For Ultrasonic Waves (AREA)

Abstract

The invention concerns an ultrasound device for checking the quality of a composite material structure (11) during the production cycle. The device is intended to be incorporated in production tooling, of the type enabling the LRI process to be performed, in which the composite material structure is placed between two moulds during the production cycle. To that end, it comprises a layer of piezoelectric material (22) deposited on the face of one (13) of the moulds, opposite the face which is in contact with the structure (1), and a film (21) of flexible material which is electrically insulating and one face of which is placed against the outer face of the layer (22). This face of the film further comprises conductive pads (31) which are thus placed in contact with the piezoelectric material, it being possible for each pad to be energized by electric voltage applied by means of a conductive strip (32). Each pad (31) forms an independent ultrasonic transducer with the region of the layer (22) opposite which it is placed.

Description

Dispositif reconfigurable de contrôle d'une structure composite par ultrasons DOMAINE DE L INVENTION  Reconfigurable Device for Controlling an Ultrasonic Composite Structure FIELD OF THE INVENTION
L'invention se rapporte au domaine général des moyens d'instrumentation pour le suivi de la qualité de fabrication de structures en matériau composite tout au long du processus de fabrication. Elle se rapporte en particulier aux moyens mettant en œuvre des capteurs, des transducteurs, ultrasonores pour réaliser ce suivi. The invention relates to the general field of instrumentation means for monitoring the manufacturing quality of composite material structures throughout the manufacturing process. It relates in particular to the means implementing sensors, transducers, ultrasound to perform this monitoring.
CONTEXTE DE L'INVENTION - ART ANTERIEUR Pour contrôler la qualité de fabrication de structures en matériau composite, au cours du processus même de fabrication, il est connu d'utiliser des moyens de mesures mettant en œuvre des transducteurs ultrasonores dont le rôle est d'émettre une onde ultrasonore au travers de la structure en cours de fabrication et de capter l'onde ayant traversé cette structure, ces transducteurs fonctionnant de manière connue en transmission ou en réflexion. Le suivi de processus de fabrication par ultrason est ainsi généralement réalisé au moyen de capteurs ultrasonores, des transducteurs piézoélectriques, qui supportent les températures de cuisson appliquées au cours de ce processus. BACKGROUND OF THE INVENTION - PRIOR ART In order to control the manufacturing quality of structures made of composite material, during the actual manufacturing process, it is known to use measuring means using ultrasonic transducers whose role is to to emit an ultrasonic wave through the structure during manufacture and to pick up the wave that has passed through this structure, these transducers operating in a known manner in transmission or in reflection. Ultrasonic manufacturing process monitoring is thus generally carried out by means of ultrasonic sensors, piezoelectric transducers, which support the baking temperatures applied during this process.
Cependant, ces moyens sont généralement intégrés aux outillages de fabrication eux-mêmes de sorte que les transducteurs utilisés occupent généralement des positions fixes, prédéterminées, par rapport à la surface de la structure en cours de fabrication. Ces capteurs sont disposés à demeure sur les outillages et moules utilisés pour la fabrication. Ils sont généralement collés sur les éléments de ces outillages en contact avec la structure en cours de fabrication ou, alternativement, insérés dans ces mêmes éléments qui ont alors subi un usinage leur permettant d'intégrer ces capteurs. Or, notamment lors des phases de mises au point des procédés pour réaliser ces structures en matériau composite, en particulier dans le cas de procédés de fabrication mettant en œuvre la technique LRI (acronyme de la dénomination anglo-saxonne "Liquid Resin Injection"), l'usage de l'instrumentation ultrasonore apporte une aide précieuse. Cette aide est néanmoins à l'heure actuelle limitée par le fait que l'on utilise des capteurs ultrasonores dont la position au sein de l'outillage ne peut être facilement modifiée, une telle modification entraînant nécessairement une modification des moyens de fabrication eux-mêmes. However, these means are generally integrated with the manufacturing tools themselves so that the transducers used generally occupy fixed, predetermined positions with respect to the surface of the structure being manufactured. These sensors are permanently placed on the tools and molds used for manufacturing. They are generally glued on the elements of these tools in contact with the structure during manufacture or, alternatively, inserted in these same elements which have then undergone machining allowing them to integrate these sensors. However, especially during the development phases of the processes for producing these composite material structures, in particular in the case of manufacturing processes using the LRI technique (acronym for the English name "Liquid Resin Injection"), the use of ultrasonic instrumentation provides valuable assistance. However, this aid is currently limited by the fact that ultrasonic sensors are used whose position within the tool can not be easily modified, such a modification necessarily entailing a modification of the manufacturing means themselves. .
Cependant, il apparaît particulièrement avantageux de pouvoir, si besoin est, observer plus précisément une zone de la structure à réaliser plutôt qu'une autre, en augmentant par exemple le nombre de voies de mesure au niveau cette zone d'intérêt et ce, le temps nécessaire à cette observation, puis de pouvoir revenir à une configuration de capteurs plus standard, dans laquelle les capteurs sont par exemple répartis uniformément en regard de la structure en cours de fabrication. Pour autant, une telle possibilité n'est réellement avantageuse que si la reconfiguration de la répartition des capteurs n'est ni longue à mettre en œuvre, ni coûteuse en termes de moyens matériels ou de processus de fabrication, ce qui n'est pas le cas avec les dispositifs de mesures ultrasonores actuellement utilisés. PRESENTA TION DE L INVENTION  However, it appears particularly advantageous to be able, if necessary, to observe more precisely one area of the structure to be achieved rather than another, for example by increasing the number of measurement channels at this area of interest and this, the time necessary for this observation, then to be able to return to a configuration of more standard sensors, in which the sensors are for example evenly distributed with respect to the structure being manufactured. However, such a possibility is really advantageous only if the reconfiguration of the distribution of the sensors is neither long to implement nor expensive in terms of material resources or manufacturing process, which is not the case with the ultrasonic measuring devices currently used. PRESENTA TION OF THE INVENTION
Un but de l'invention est de proposer une solution pour disposer d'un moyen de mesure comportant une pluralité de capteurs ultrasonores, destiné à réaliser des mesures par ultrasons sur des pièces en matériau composite tout au long du processus de fabrication de ces pièces, les capteurs ultrasonores étant positionnés au niveau de la surface de la pièce analysée, ce moyen permettant de réaliser de manière simple et peu coûteuse des mesures avec différents arrangements de capteurs. An object of the invention is to propose a solution for having a measuring means comprising a plurality of ultrasonic sensors, intended to perform ultrasonic measurements on composite material parts throughout the manufacturing process of these parts, the ultrasonic sensors being positioned at the surface of the analyzed part, this means making it possible to simply and inexpensively carry out measurements with different sensor arrangements.
Un autre but de l'invention est de proposer un moyen de mesure par ultrasons qui, tout en coopérant avec les moyens de fabrication des pièces en matériau composite que l'on souhaite contrôler tout au long du processus de fabrication, soit distinct de ces moyens.  Another object of the invention is to propose an ultrasonic measurement means which, while cooperating with the manufacturing means of the composite material parts which it is desired to control throughout the manufacturing process, is distinct from these means. .
Autrement dit, un but de l'invention consiste à trouver une solution pour disposer d'une instrumentation facilement reconfigurable et modifiable de façon à optimiser les mesures ultrasonores elles-mêmes destinées à optimiser le procédé de fabrication. In other words, an object of the invention is to find a solution to have an instrumentation easily reconfigurable and editable to optimize the ultrasonic measurements themselves to optimize the manufacturing process.
A cet effet l'invention a pour objet un dispositif de contrôle d'une structure en matériau composite au cours de sa fabrication, ladite structure étant réalisée dans un espace limité par la face interne d'une première forme et par la face interne d'une seconde forme, ledit dispositif comportant une pluralité de capteurs ultrasonores disposés au voisinage de la structure de façon à ce que chaque capteur ultrasonore puisse émettre une onde ultrasonore à l'intérieur de la structure et capter l'écho renvoyé par cette structure. Le dispositif comporte une couche de matériau piézoélectrique dont la face interne est disposée sur la face externe de la seconde forme et un film en matériau souple isolant électrique agencé de façon à être plaqué contre la face externe de la couche de matériau piézoélectrique. Ledit film en matériau souple comporte sur sa face en contact avec la couche de matériau piézoélectrique une pluralité d'électrodes, chaque électrode pouvant être excitées de manière séparée par un signal de commande transmis par un conducteur. La surface conductrice de chacune des électrodes est agencée de façon à être en contact avec la surface de la couche de matériau piézoélectrique de sorte que chaque électrode forme avec la zone de la couche de matériau piézoélectrique, en regard de laquelle elle est placée, un capteur ultrasonore distinct. To this end, the subject of the invention is a device for controlling a composite material structure during its manufacture, said structure being produced in a space limited by the internal face of a first form and by the internal face of a second form, said device comprising a plurality of ultrasonic sensors arranged in the vicinity of the structure so that each ultrasonic sensor can emit an ultrasonic wave inside the structure and pick up the echo returned by this structure. The device comprises a layer of piezoelectric material whose inner face is disposed on the outer face of the second form and a film of flexible electrical insulating material arranged to be pressed against the outer face of the layer of piezoelectric material. Said film of flexible material comprises on its face in contact with the layer of piezoelectric material a plurality of electrodes, each electrode can be excited separately by a control signal transmitted by a conductor. The conductive surface of each of the electrodes is arranged to be in contact with the surface of the layer of piezoelectric material so that each electrode forms with the zone of the layer of piezoelectric material, opposite which it is placed, a sensor separate ultrasound.
Selon diverses dispositions ou propriétés, éventuellement utilisées en conjonction le dispositif selon l'invention peut en outre présenter des caractéristiques additionnelles. According to various arrangements or properties, possibly used in conjunction, the device according to the invention may furthermore have additional characteristics.
Ainsi, selon un mode de réalisation, la couche de matériau piézoélectrique est directement formée sur la face externe de la seconde forme par mise en œuvre d'un procédé de type sol-gel. Thus, according to one embodiment, the layer of piezoelectric material is directly formed on the outer face of the second form by implementing a sol-gel type process.
Selon un autre mode de réalisation, le film isolant électrique en matériau souple est réalisé dans un matériau polymère de type polyimide. Selon un autre mode de réalisation, les électrodes sont formées par des pastilles conductrices disposées en surface, sur la face dudit film en contact avec la couche de matériau piézoélectrique, chaque électrode étant alimentée électriquement par un élément conducteur constitué par une piste conductrice disposée soit sur la face opposée du film soit dans l'épaisseur du film. According to another embodiment, the electrical insulating film of flexible material is made of a polyimide-type polymer material. According to another embodiment, the electrodes are formed by conductive pads disposed on the surface, on the face of said film in contact with the layer of piezoelectric material, each electrode being electrically powered by a conductive element constituted by a conductive track disposed either on the opposite side of the film is in the thickness of the film.
Selon une variante de réalisation du mode précédent, les pistes conductrices alimentant les différentes électrodes sont pourvues à leur extrémité d'une connectique permettant d'appliquer une tension d'excitation à chaque électrode. According to an alternative embodiment of the previous mode, the conductive tracks supplying the different electrodes are provided at their end with a connector for applying an excitation voltage to each electrode.
Selon un autre mode de réalisation, chaque électrode est constituée par une pastille conductrice unique dont les dimensions sont définies de façon à ce que le capteur ultrasonore formé par cette électrode et la couche de matériau piézoélectrique émette une onde ultrasonore sensiblement plane. According to another embodiment, each electrode is constituted by a single conductive pad whose dimensions are defined so that the ultrasonic sensor formed by this electrode and the layer of piezoelectric material emits a substantially flat ultrasound wave.
Selon un autre mode de réalisation, alternatif du précédent, chaque électrode est constituée par une pastille conductrice formée d'une pluralité de pastilles élémentaires dont les dimensions sont définies de façon à ce que le capteur ultrasonore formé par une pastille élémentaire et la couche de matériau piézoélectrique émette une onde ultrasonore sensiblement sphérique ou cylindrique; les pastilles élémentaires étant configurées de façon à pouvoir être commandées séparément. According to another alternative embodiment of the above, each electrode is constituted by a conductive pad formed of a plurality of elementary pellets whose dimensions are defined so that the ultrasonic sensor formed by an elementary pellet and the layer of material piezoelectric emits a substantially spherical or cylindrical ultrasonic wave; the elementary pellets being configured so that they can be ordered separately.
Selon une variante de réalisation du mode précédent, les pastilles élémentaires sont agencées les unes par rapport aux autres de telle façon qu'elles puissent être excitées de façon à constituer un seul capteur ultrasonore. According to an alternative embodiment of the previous mode, the elementary pellets are arranged relative to each other so that they can be excited so as to constitute a single ultrasonic sensor.
Selon un autre mode de réalisation, pour chaque électrode, la tension d'excitation est appliquée entre ladite électrode et une masse commune constituée par la seconde forme. Selon un autre mode de réalisation, la couche de matériau piézoélectrique déposée sur la face externe de la seconde forme présente une épaisseur e2 de l'ordre de plusieurs dizaines de microns. Selon un autre mode de réalisation, le film en matériau souple présente une épaisseur βι de l'ordre de quelques centaines de microns. According to another embodiment, for each electrode, the excitation voltage is applied between said electrode and a common ground constituted by the second form. According to another embodiment, the layer of piezoelectric material deposited on the outer face of the second form has a thickness e 2 of the order of several tens of microns. According to another embodiment, the film of flexible material has a thickness βι of the order of a few hundred microns.
L'invention a également pour objet un outillage de fabrication d'une structure en matériau composite mettant en œuvre le procédé LRI, ledit outillage comportant un premier élément, ou moule, et un second élément, ou "caul plate" en vis-à-vis du premier élément, la structure réalisée étant placée entre les faces internes de ces deux éléments. L'outillage comporte un dispositif de contrôle par ultrasons selon l'invention dont la couche de matériau piézoélectrique est formée sur la face externe de la "caul plate", le film en matériau souple étant quant à lui plaqué contre ladite couche. The invention also relates to a tool for manufacturing a composite material structure implementing the LRI method, said tooling comprising a first element, or mold, and a second element, or "caul plate" vis-à-vis screw of the first element, the realized structure being placed between the inner faces of these two elements. The tooling comprises an ultrasound control device according to the invention, the layer of piezoelectric material is formed on the outer face of the "flat caul", the film of flexible material is in turn pressed against said layer.
DESCRIPTION DES FIGURES DESCRIPTION OF THE FIGURES
Les caractéristiques et avantages de l'invention seront mieux appréciés grâce à la description qui suit, description qui s'appuie sur les figures annexées qui présentent: The characteristics and advantages of the invention will be better appreciated thanks to the following description, which is based on the appended figures which show:
- la figurel , une illustration schématique d'un dispositif de contrôle par ultrasons de la fabrication d'une structure composite selon l'art antérieur, dans le cadre d'une fabrication par procédé LRI ; - The figure, a schematic illustration of an ultrasonic testing device of the manufacture of a composite structure according to the prior art, in the context of a process manufacturing LRI;
- la figure 2, une illustration schématique d'un dispositif de contrôle par ultrasons de la fabrication d'une structure composite selon l'invention, dans le cadre d'une fabrication par procédé LRI ;  - Figure 2 is a schematic illustration of an ultrasonic testing device for the manufacture of a composite structure according to the invention, in the context of a manufacturing process LRI;
- la figure 3, une vue schématique partielle d'un outillage de fabrication d'une structure par procédé LRI intégrant le dispositif selon l'invention;  FIG. 3 is a partial schematic view of a tool for manufacturing an LRI process structure incorporating the device according to the invention;
- la figure 4, une illustration schématique d'une forme de réalisation du dispositif selon l'invention;  FIG. 4, a schematic illustration of an embodiment of the device according to the invention;
- la figure 5, une illustration du principe de fonctionnement du dispositif dans la forme de réalisation de la figure 4;  FIG. 5, an illustration of the operating principle of the device in the embodiment of FIG. 4;
- la figure 6, une illustration schématique d'une autre forme de réalisation du dispositif selon l'invention; - la figure 7, une illustration du principe de fonctionnement du dispositif dans la forme de réalisation de la figure 6. FIG. 6, a schematic illustration of another embodiment of the device according to the invention; FIG. 7, an illustration of the principle of operation of the device in the embodiment of FIG. 6.
DESCRIPTION DETAILLEE DETAILED DESCRIPTION
Pour des raisons de clarté, le dispositif selon l'invention est présenté dans la suite de la description au travers de son application dans le cadre d'un outillage de fabrication de structures en matériau composite mettant en œuvre le procédé LRI (acronyme de la dénomination anglo-saxonne "Liquid Resin Injection"). Cet exemple de mise en œuvre n'est bien entendu nullement limitatif de la portée ou de l'objet de l'invention, le dispositif selon l'invention pouvant être mis en œuvre et intégrés à tout type d'outillage de fabrication de structures en matériau composite, pour autant que ces outillages comportent les éléments avec lesquels le dispositif selon l'invention coopère. For the sake of clarity, the device according to the invention is presented in the following description through its application in the context of a tool for manufacturing structures made of composite material implementing the LRI process (acronym for the name Anglo-Saxon "Liquid Resin Injection"). This example of implementation is of course in no way limiting the scope or object of the invention, the device according to the invention can be implemented and integrated into any type of tool for manufacturing structures in composite material, provided that these tools comprise the elements with which the device according to the invention cooperates.
La figure 1 présente de manière très schématique un dispositif de contrôle par ultrasons de la fabrication d'une structure composite selon l'art antérieur, dans le cadre d'un outillage de fabrication de structures en matériau composite mettant en œuvre le procédé LRI. FIG. 1 very schematically shows a device for ultrasonic testing of the manufacture of a composite structure according to the prior art, as part of a tool for manufacturing structures made of composite material implementing the LRI process.
De manière connue, cet outillage de fabrication comporte en particulier un élément 12, appelé moule, dans lequel est injectée la résine constituant la structure en matériau composite 1 1 à fabriquer ainsi qu'un élément 13 appelé "caul plate" ou "plaque de couverture", qui assure la calibration en épaisseur et en planéité de la structure 1 1 à injecter, agencés de telle sorte que la structure en cours de fabrication se trouve placée entre le moule 12 et la "caul plate" 13.  In known manner, this manufacturing tool comprises in particular an element 12, called mold, in which is injected the resin constituting the composite material structure 1 1 to be manufactured and an element 13 called "caul plate" or "cover plate ", which ensures the calibration in thickness and flatness of the structure 1 1 to be injected, arranged so that the structure being manufactured is placed between the mold 12 and the" caul plate "13.
Cet outillage comporte également au moins une membrane 14, une paroi souple, agencée de façon à délimiter, avec le moule 12, un espace 15 entourant à la fois la structure 1 1 et la "caul plate" 13. Cette membrane 14 est par ailleurs configurée de manière à ce que l'on puisse faire le vide dans l'espace 15 de sorte que, la membrane enserrant la "caul plate" 13 et la structure 1 1 , celles-ci soient plaquées l'une contre l'autre et contre le moule 12. Le dispositif de contrôle par ultrasons intégré à cet outillage de fabrication est constitué par un certain nombre de capteurs ultrasonores 16 disposés sur la "caul plate", la surface active des capteurs 16 étant placée en surface de la "caul plate", en regard de la surface de la structure 1 1 , de façon à pouvoir propager une onde ultrasonore au travers de celle-ci. This tooling also comprises at least one membrane 14, a flexible wall, arranged to delimit, with the mold 12, a space 15 surrounding both the structure 1 1 and the "caul plate" 13. This membrane 14 is moreover configured so that it is possible to evacuate in the space 15 so that, the membrane enclosing the "flat caul" 13 and the structure 1 1, they are pressed against each other and against the mold 12. The ultrasound control device integrated into this manufacturing tool is constituted by a number of ultrasonic sensors 16 arranged on the "flat caul", the active surface of the sensors 16 being placed on the surface of the "flat caul", opposite the surface of the structure 1 1, so as to propagate an ultrasonic wave through it.
Le nombre et la disposition des capteurs 16 sont fonction des dimensions de la structure 1 1 réalisée ainsi que de la répartition des zones de la structure 1 1 que l'on souhaite analyser. Ainsi si l'on souhaite, par exemple, analyser de manière uniforme la structure 1 1 réalisée, les capteurs ultrasonores 16 sont disposés de manière régulière en regard de la surface de la structure 1 1 .  The number and arrangement of the sensors 16 are a function of the dimensions of the structure 1 1 made and the distribution of the areas of the structure 1 1 that it is desired to analyze. Thus, if it is desired, for example, to analyze the structure 11 made uniformly, the ultrasonic sensors 16 are arranged in a regular manner facing the surface of the structure 11.
Afin de s'assurer d'un positionnement et d'une orientation corrects des capteurs16 vis-à-vis de la structure 1 1 à réaliser, et ce tout au long du cycle de fabrication de cette structure, on intègre généralement les capteurs 16 directement dans la "caul plate" 13, comme illustré par la figure 1 . Ce type de montage permet en effet, du fait de l'enchâssement des capteurs 16 dans la "caul plate" 13, de s'assurer du positionnement correct des faces actives des capteurs 16 vis-à-vis de la surface de la structure 1 1 en cours de fabrication, et de simplifier le maintien en place de ces capteurs.  In order to ensure correct positioning and orientation of the sensors 16 with respect to the structure 1 1 to be produced, and this throughout the manufacturing cycle of this structure, the sensors 16 are generally integrated directly in the "flat caul" 13, as illustrated in FIG. This type of assembly makes it possible, because of the entrenchment of the sensors 16 in the "flat caul" 13, to ensure the correct positioning of the active faces of the sensors 16 vis-à-vis the surface of the structure 1 1 in the course of manufacture, and to simplify the maintenance in place of these sensors.
Selon le type d'analyse par ultrasons effectuée, analyse en transmission ou analyse en réflexion, les capteurs ultrasonores 16 utilisés, peuvent être constitués chacun d'un seul élément configuré pour émettre ou recevoir une onde ultrasonore ou bien d'un élément émetteur 16e et d'un élément récepteur 16r. Dans le premier cas les capteurs 16 sont implantés dans la seule "caul plate" 13, tandis que dans le second cas, illustré par la figure 1 , l'élément émetteur 16e est implanté dans la "caul plate" 13 et l'élément récepteur 16r dans le moule 12, la face active des éléments récepteurs 16r étant alors dirigée vers la surface de la structure 1 1 . Comme cela a été dit précédemment une telle implantation de capteurs à l'intérieur de l'outillage de fabrication, présente pour principal avantage de rendre la mise en place de ces capteurs simple et permanente. Ainsi si l'on souhaite fabriquer une série de structures 1 1 identiques, il n'est pas nécessaire de déposer les capteurs 16 pour extraire une structure en fin de fabrication de même qu'il n'est pas nécessaire de procéder à un nouveau montage des capteurs pour lancer la fabrication de la structure suivante. Depending on the type of ultrasonic analysis performed, transmission analysis or reflection analysis, the ultrasonic sensors 16 used may each consist of a single element configured to transmit or receive an ultrasonic wave or a transmitter element 16 and of a receiver element 16r. In the first case the sensors 16 are implanted in the only "flat caul" 13, while in the second case, illustrated in FIG. 1, the emitter element 16e is implanted in the "flat caul" 13 and the receiving element 16r in the mold 12, the active face of the receiving elements 16r then being directed towards the surface of the structure 1 1. As previously mentioned, such implantation of sensors inside the manufacturing tool has the main advantage of making the installation of these sensors simple and permanent. Thus if one wishes to manufacture a series of identical structures 1 1, it is not necessary to deposit the sensors 16 to extract a structure at the end. of manufacture as it is not necessary to proceed to a new assembly of the sensors to start the manufacture of the following structure.
En revanche une telle implantation présente l'inconvénient majeur de particulariser la "caul plate" 13 et éventuellement le moule 12, le moule et la "caul plate" étant alors adaptés à un test particulier et à une disposition, une répartition particulière, figée, des capteurs 16 en regard de la surface de la structure 1 1 à contrôler.  On the other hand, such an implantation has the major disadvantage of particularizing the "flat caul" 13 and possibly the mold 12, the mold and the "flat caul" being then adapted to a particular test and a disposition, a particular, fixed distribution, sensors 16 facing the surface of the structure 1 1 to be controlled.
Par suite si l'on souhaite pour diverses raisons procéder à un arrangement différent des capteurs 16 il est nécessaire de modifier la "caul plate" 13 et éventuellement le moule 12, ce qui constitue une opération coûteuse et nécessite de consacrer du temps au démontage et au remontage de ces éléments, ce qui est préjudiciable en termes de cadence de fabrication. La figure 2 présente une vue schématique générale du dispositif de contrôle par ultrasons selon l'invention, présenté dans une configuration matérielle semblable à celle du dispositif de la figure 1 , connu de l'art antérieur. La configuration présentée ici, qui correspond à une analyse en réflexion, peut aisément être adaptée à une analyse en transmission.  As a result if it is desired for various reasons to make a different arrangement of the sensors 16 it is necessary to modify the "caul plate" 13 and possibly the mold 12, which is an expensive operation and requires time to disassemble and the reassembly of these elements, which is detrimental in terms of production rate. FIG. 2 presents a general schematic view of the ultrasound control device according to the invention, presented in a hardware configuration similar to that of the device of FIG. 1, known from the prior art. The configuration presented here, which corresponds to a reflection analysis, can easily be adapted to a transmission analysis.
Comme l'illustre la figure 2, le dispositif selon l'invention comporte deux éléments distincts qui coopèrent, une couche de céramique piézoélectrique 22 et un film en matériau souple 21 .  As illustrated in FIG. 2, the device according to the invention comprises two distinct cooperating elements, a piezoelectric ceramic layer 22 and a film of flexible material 21.
La couche de céramique piézoélectrique 22, est une couche mince disposée sur la face externe de la "caul plate" 13, c'est à dire la face opposée à la face en contact avec la surface de la structure 1 1 , qui couvre la totalité de la "caul plate", ou tout au moins la totalité de la surface de la "caul plate" située en regard de la structure 1 1 à contrôler. The piezoelectric ceramic layer 22, is a thin layer disposed on the outer face of the "flat caul" 13, that is to say the face opposite to the face in contact with the surface of the structure 1 1, which covers the entire the "caul plate", or at least the entire surface of the "caul plate" located opposite the structure 1 1 to control.
Selon un mode de réalisation préféré de l'invention, la couche 22 de céramique piézoélectrique est réalisée par un procédé de type sol-gel, à partir d'un substrat déposé en phase liquide ou visqueuse sur la surface externe de la "caul plate", par technique "piezospray" par exemple, et durci.  According to a preferred embodiment of the invention, the layer 22 of piezoelectric ceramic is made by a sol-gel type process, from a substrate deposited in the liquid or viscous phase on the outer surface of the "flat caul" , by "piezospray" technique for example, and hardened.
Cependant tout procédé connu de l'homme du métier permettant de déposer à la surface de la "caul plate" une couche mince de matériau piézoélectrique peut alternativement être utilisé pour réaliser la couche 22. Le film 21 en matériau souple, est quant à lui configuré de façon à être plaqué contre la surface externe de la couche 22 de céramique piézoélectrique, c'est à dire la face opposée à la face en contact avec la surface de la "caul plate" 13. However, any method known to those skilled in the art for depositing on the surface of the "flat caul" a thin layer of piezoelectric material may alternatively be used to make the layer 22. The film 21 of flexible material is, for its part, configured to be pressed against the outer surface of the piezoelectric ceramic layer 22, ie the face opposite to the face in contact with the surface of the flat caul "13.
Selon l'invention, comme l'illustre la vue détaillée de la figure 3, ce film According to the invention, as shown in the detailed view of FIG. 3, this film
21 comporte une pluralité d'électrodes 31 de faible épaisseur, disposées en surface. La face 33 dudit film 21 qui porte les électrodes 31 est destinée à être plaquée contre la face externe de la couche 22 de matériau piézoélectrique. Le film 21 comporte encore un ensemble de conducteurs électriques 32, qui débouchent à l'extérieur du film par une connectique appropriée et qui permettent d'appliquer un signal électrique à chacune des électrodes 31 . 21 comprises a plurality of electrodes 31 of small thickness, arranged on the surface. The face 33 of said film 21 which carries the electrodes 31 is intended to be pressed against the outer face of the layer 22 of piezoelectric material. The film 21 further comprises a set of electrical conductors 32, which open out of the film by appropriate connectors and which make it possible to apply an electrical signal to each of the electrodes 31.
Selon l'invention également, le film 21 peut être réalisé dans tout matériau isolant électrique souple approprié, présentant notamment les caractéristiques de tenue en température et en pression requises, les conditions de température et de pression étant celles imposées par le procédé de fabrication de la structure 1 1 . Préférentiellement le film 21 est un film de matériau polymère du groupe des polyimides, par exemple un film de Kapton®.  According to the invention also, the film 21 may be made of any suitable flexible electrical insulating material, in particular having the required temperature and pressure resistance characteristics, the temperature and pressure conditions being those imposed by the manufacturing method of the structure 1 1. Preferably, the film 21 is a film of polymeric material of the polyimide group, for example a Kapton® film.
En ce qui concerne les électrodes 31 et les conducteurs 32, ceux-ci sont préférentiellement réalisés, à la façon d'un circuit imprimé, sous forme de pastilles et de pistes en matériau conducteur, des pastilles et des pistes métalliques par exemple.  As regards the electrodes 31 and the conductors 32, these are preferably made, in the manner of a printed circuit, in the form of pellets and tracks of conductive material, pellets and metal tracks for example.
Comme l'illustre la figure 3, les pastilles formant les électrodes 31 sont déposées en surface, sur celles des faces du film souple 21 destinée à être mise en contact avec la couche 22 de matériau piézoélectrique. Les pistes conductrices 32, quant à elles, sont implantées sur l'autre face ou encore, comme illustré par la figure 3, dans l'épaisseur du film, de façon à ne pas entrer en contact avec la couche de matériau piézoélectrique 22.  As illustrated in FIG. 3, the pellets forming the electrodes 31 are deposited on the surface, on those of the faces of the flexible film 21 intended to be put in contact with the layer 22 of piezoelectric material. The conductive tracks 32, for their part, are implanted on the other side or, as illustrated in FIG. 3, in the thickness of the film, so as not to come into contact with the layer of piezoelectric material 22.
L'ensemble électrodes-pistes conductrices est par ailleurs réalisé et intégré au film souple par toute méthode de réalisation de circuits imprimés souples appropriée, connue de l'homme du métier.  The electrodes-conductive tracks assembly is also realized and integrated into the flexible film by any method of producing flexible printed circuit boards, known to those skilled in the art.
D'un point de vu dimensionnel, la couche 22 de matériau piézoélectrique déposée sur la "caul plate" présente une épaisseur e2 de l'ordre de quelques dizaines de microns, typiquement de l'ordre de 70μιτι, tandis que le film 21 en matériau souple présente une épaisseur βι de l'ordre de quelques centaines de microns, typiquement de l'ordre de 200μιτι. Les électrodes 31 et les pistes conductrices 32 implantées sur le film 21 ont quant à elles une épaisseur de l'ordre de la dizaine de micron à quelques dizaines de microns. Il est à noter par ailleurs que l'épaisseur et la nature du film de matériau piézoélectrique détermine la fréquence de résonnance de la couche 22. D'un point de vue fonctionnel, l'ensemble constitué par la couche de matériau piézoélectrique déposée sur la "caul plate" et les électrodes 31 disposées à la surface du film en matériau souple 21 forment une pluralité de capteurs ultrasonores disposés à la surface de la "caul plate" en regard de la structure 1 1 à analyser, la répartition des capteurs ultrasonores ainsi formés étant simplement définie par la disposition des électrodes à la surface du film souple. From a dimensional point of view, the layer 22 of piezoelectric material deposited on the "flat caul" has a thickness e 2 of the order of a few tens of microns, typically of the order of 70μιτι, while the film 21 of flexible material has a thickness βι of the order of a few hundred microns, typically of the order of 200μιτι. The electrodes 31 and the conductive tracks 32 implanted on the film 21 have a thickness of about ten microns to several tens of microns. It should also be noted that the thickness and the nature of the film of piezoelectric material determines the resonance frequency of the layer 22. From a functional point of view, the assembly consisting of the layer of piezoelectric material deposited on the caul plate "and the electrodes 31 disposed on the surface of the film of flexible material 21 form a plurality of ultrasonic sensors disposed on the surface of the" caul plate "facing the structure 1 1 to be analyzed, the distribution of ultrasonic sensors thus formed being simply defined by the arrangement of the electrodes on the surface of the flexible film.
Lorsqu'elle est excitée par un signal, une tension, électrique, chacune des électrodes forme, avec la zone de la couche de matériau piézoélectrique située entre elle et la surface de la "caul plate", un transducteur piézoélectrique capable d'émettre une onde ultrasonore au travers de la structure 1 1 et de capter l'écho produit par la traversée de ce signal au travers de la structure 1 1 . On réalise ainsi, avantageusement, un ensemble de capteurs ultrasonores dont le fonctionnement est identique, dans son principe, à celui des capteurs individuels 16 présentés sur la figure 1 .  When excited by a signal, an electrical voltage, each of the electrodes forms, with the zone of the layer of piezoelectric material situated between it and the surface of the "flat caul", a piezoelectric transducer capable of emitting a wave ultrasound through the structure 1 1 and capture the echo produced by crossing this signal through the structure 1 1. Thus, advantageously, a set of ultrasonic sensors whose operation is identical, in principle, to that of the individual sensors 16 shown in FIG.
Il est à noter que, pour assurer un bon fonctionnement des capteurs ultrasonores ainsi réalisés, il est nécessaire d'assurer le contact le meilleur possible entre les électrodes 31 d'une part et la surface de la couche 22 de matériau piézoélectrique d'autre part. Ce contact est assuré en plaquant la face de ce film souple qui porte ces électrodes sur la surface de la couche 22 par tout moyen approprié, adapté au fonctionnement de l'outillage de fabrication auquel le dispositif de contrôle par ultrason selon l'invention est intégré. Dans le cadre d'un outillage de fabrication mettant en œuvre un procédé de type LRI, tel que celui schématisé dans les figures 2 et 3, le maintien en contact du film 21 avec la couche piézoélectrique 22 peut avantageusement être réalisé, de façon incidente, par la dépression introduite dans l'espace 15 délimité par la membrane 14 qui renferme la structure 1 1 en cours de fabrication, ainsi que la "caul plate" 13 sur laquelle est déposée la couche de matériau piézoélectrique 22 et le film souple 21 sur lequel sont disposées les électrodes 31 . It should be noted that, to ensure proper operation of the ultrasonic sensors thus produced, it is necessary to ensure the best possible contact between the electrodes 31 on the one hand and the surface of the layer 22 of piezoelectric material on the other hand . This contact is provided by plating the face of this flexible film which carries these electrodes on the surface of the layer 22 by any appropriate means, adapted to the operation of the manufacturing tooling to which the ultrasonic control device according to the invention is integrated . In the context of a manufacturing tool implementing an LRI type process, such as that shown diagrammatically in FIGS. 2 and 3, keeping the film 21 in contact with the piezoelectric layer 22 can advantageously be realized, incidentally, by the depression introduced into the space 15 delimited by the membrane 14 which contains the structure 1 1 during manufacture, and the "flat caul" 13 on which is deposited the layer of piezoelectric material 22 and the flexible film 21 on which the electrodes 31 are arranged.
La structure décrite dans le texte qui précède permet avantageusement de réaliser un dispositif comportant une pluralité de capteurs ultrasonores, de transducteurs acoustiques, ayant des fonctionnalités similaires à celle des capteurs ultrasonores généralement utilisés, tout en présentant une plus grande facilité de mise en place et d'utilisation. En effet, dans les dispositifs connus généralement utilisés, les capteurs sont intégrés à la structure même de la "caul plate" 13 et éventuellement du moule 12. Par suite, la modification du nombre et de la répartition des capteurs à la surface de la pièce à contrôler nécessite de modifier ou de remplacer la "caul plate" 13 et éventuellement le moule 12 de façon à y loger les capteurs selon le nouvel agencement souhaité. The structure described in the foregoing text advantageously makes it possible to produce a device comprising a plurality of ultrasonic sensors, acoustic transducers, having functionalities similar to that of the ultrasonic sensors generally used, while at the same time having a greater ease of installation and use. 'use. Indeed, in the generally known known devices, the sensors are integrated into the structure of the "flat caul" 13 and possibly of the mold 12. As a result, the modification of the number and distribution of the sensors on the surface of the part to be controlled requires modifying or replacing the "caul plate" 13 and possibly the mold 12 so as to accommodate the sensors according to the new desired arrangement.
Or, dans le cas du dispositif selon l'invention, dans la mesure où la couche de matériau piézoélectrique déposée à la surface de la "caul plate" est une couche uniforme et où la disposition des capteurs est définie simplement par l'arrangement des pastilles conductrices formant les électrodes 31 à la surface du film souple 21 , changer la disposition et le nombre des capteurs devient avantageusement simple et ne nécessite que le remplacement du film souple 21 . On dispose ainsi d'un dispositif de contrôle aisément reconfigurable par simple remplacement ou repositionnement du film souple 21 , le remplacement du film souple existant par un autre film présentant un arrangement d'électrodes différent présentant un coût avantageusement inférieur aux coûts engendrés par la modification ou le remplacement de la "caul plate" 13 et éventuellement du moule 12.  However, in the case of the device according to the invention, insofar as the layer of piezoelectric material deposited on the surface of the "flat caul" is a uniform layer and where the arrangement of the sensors is defined simply by the arrangement of the pellets conductive forming the electrodes 31 on the surface of the flexible film 21, change the arrangement and the number of sensors advantageously becomes simple and requires only the replacement of the flexible film 21. This provides a control device easily reconfigurable simply by replacing or repositioning the flexible film 21, replacing the existing flexible film with another film having a different electrode arrangement with a cost advantageously less than the costs generated by the modification or replacing the "flat caul" 13 and possibly the mold 12.
Les figures 4 à 7 permettent de mettre en évidence un autre avantage que présente l'utilisation du dispositif selon l'invention, avantage qui tient à la variété de configurations de capteurs qu'il est possible de mettre en œuvre du fait de la structure même du dispositif selon l'invention. Comme il a été dit précédemment, chaque capteur du dispositif selon l'invention est constitué par l'électrode correspondante disposée sur le film souple 21 et par la zone de la couche 22 de matériau piézoélectrique située en regard de cette électrode. De la sorte les caractéristiques de chacun des capteurs du dispositif selon l'invention peuvent être définies séparément en jouant simplement sur la forme des électrodes 31 disposées sur le film souple 21 , chaque électrode pouvant avoir une forme et des dimensions propres. FIGS. 4 to 7 show another advantage that the use of the device according to the invention has, which advantage is due to the variety of sensor configurations that can be implemented because of the structure itself of the device according to the invention. As has been said above, each sensor of the device according to the invention consists of the corresponding electrode disposed on the flexible film 21 and the area of the layer 22 of piezoelectric material situated opposite this electrode. In this way the characteristics of each of the sensors of the device according to the invention can be defined separately by simply playing on the shape of the electrodes 31 disposed on the flexible film 21, each electrode being able to have a shape and dimensions of its own.
La figure 4 présente une vue générale plane d'un premier type d'électrode pouvant être mis en œuvre par le dispositif selon l'invention.  FIG. 4 shows a general plane view of a first type of electrode that can be implemented by the device according to the invention.
Dans le cas de la figure 4, il s'agit d'une électrode constituée d'une unique pastille conductrice 41 dont les dimensions, longueur et largeur ou bien diamètre selon la forme de l'électrode, sont définies de façon à émettre dans la structure 1 1 analysée une onde sensiblement plane ayant, pour la fréquence acoustique émise, une puissance suffisante pour traverser la structure, tout en conservant une résolution d'analyse suffisante. Ainsi, pour une fréquence acoustique de 5MHz, fréquence déterminée par les caractéristiques du revêtement piézoélectrique, on choisira par exemple des pastilles ayant la forme de carrés de 5mm de côté.  In the case of Figure 4, it is an electrode consisting of a single conductive pad 41 whose dimensions, length and width or diameter according to the shape of the electrode, are defined to emit in the Structure 1 1 analyzed a substantially flat wave having, for the acoustic frequency emitted, sufficient power to traverse the structure, while maintaining a sufficient analysis resolution. Thus, for an acoustic frequency of 5 MHz, the frequency determined by the characteristics of the piezoelectric coating, for example, pellets having the shape of 5 mm squares will be chosen.
Une telle pastille est excitée par l'application d'une tension appropriée par l'intermédiaire d'une piste conductrice 42 reliée extérieurement à un générateur de tension, piste qui chemine par exemple dans l'épaisseur du film 21 .  Such a pellet is excited by the application of a suitable voltage via a conductive track 42 externally connected to a voltage generator, a track which travels for example in the thickness of the film 21.
Equipé avec de telles pastilles, le dispositif selon l'invention se comporte alors, comme l'illustre la figure 5, de façon semblable aux dispositifs de contrôle par ultrasons connus comportant des capteurs unitaires intégrés à l'outillage de fabrication, tout en conservant cependant ses caractéristiques avantageuses en termes de mise en place et d'interchangeabilité.  Equipped with such pellets, the device according to the invention then behaves, as illustrated in FIG. 5, in a manner similar to known ultrasonic testing devices comprising unitary sensors integrated into the manufacturing tool, while nevertheless retaining its advantageous features in terms of implementation and interchangeability.
La figure 6 présente une vue générale d'un second type d'électrode 61 pouvant être mis en œuvre par le dispositif selon l'invention dans une forme de réalisation plus sophistiquée. L'électrode présentée sous la figure 6 consiste en une pluralité d'électrodes 62 élémentaires regroupées pour former un ensemble présentant un arrangement particulier, un arrangement matriciel par exemple dans le cas de la figure 6. Figure 6 shows a general view of a second type of electrode 61 that can be implemented by the device according to the invention in a more sophisticated embodiment. The electrode shown in FIG. 6 consists of a plurality of elementary electrodes 62 grouped together for form an assembly having a particular arrangement, a matrix arrangement for example in the case of Figure 6.
Dans cet exemple de mise en œuvre, chacune des électrodes élémentaires 62 est configurée de façon à pouvoir exciter de manière indépendante par l'application d'une tension appropriée par l'intermédiaire d'une piste conductrice 63 reliée extérieurement à un générateur de tension.  In this exemplary implementation, each of the elementary electrodes 62 is configured so as to be able to excite independently by the application of a suitable voltage via a conductive track 63 connected externally to a voltage generator.
Les dimensions et la forme des électrodes élémentaires 62 sont définies de telle façon que chaque électrode élémentaire produise, lorsqu'elle est excitée, une onde sensiblement sphérique ou cylindrique. De la sorte, en fonction de la tension appliquée à chacune des électrodes élémentaires et des instants respectifs d'excitation des différentes électrodes, il est possible d'émettre une onde sonore présentant des caractéristiques particulières. The dimensions and the shape of the elementary electrodes 62 are defined in such a way that each elementary electrode produces, when excited, a substantially spherical or cylindrical wave. In this way, depending on the voltage applied to each of the elementary electrodes and the respective excitation instants of the different electrodes, it is possible to emit a sound wave having particular characteristics.
Chaque électrode 61 du dispositif permet alors de constituer, de manière avantageusement simple, un capteur ultrasonore multiéléments dont les caractéristiques acoustiques en termes de précision et de résolution, peuvent être sensiblement différentes de celle d'un capteur acoustique traditionnel tel que ceux qui équipent les dispositifs de test connus. Each electrode 61 of the device then makes it possible advantageously to constitute a multi-element ultrasonic sensor whose acoustic characteristics in terms of precision and resolution can be substantially different from that of a traditional acoustic sensor such as those which equip the devices. known test.
L'illustration de la figure 7 présente, à titre d'exemple, une application particulière pour laquelle les électrodes élémentaires 62 formant une même électrode 61 sont excitées de façon à émettre chacune une onde acoustique élémentaire se propageant à travers la structure 1 1 .  The illustration of FIG. 7 shows, by way of example, a particular application for which the elementary electrodes 62 forming the same electrode 61 are excited so as to each emit an elementary acoustic wave propagating through the structure 11.

Claims

REVENDICATIONS
1 . Dispositif de contrôle d'une structure en matériau composite (1 1 ) au cours de sa fabrication, ladite structure étant réalisée dans un espace (15) limité par la face interne d'une première forme (12) et par la face interne d'une seconde forme (13), ledit dispositif formant une pluralité de capteurs ultrasonores disposés au voisinage de la structure, chaque capteur ultrasonore émettant une onde ultrasonore à l'intérieur de la structure (1 1 ) et captant l'écho renvoyé par cette structure, caractérisé en ce qu'il comporte une couche (22) de matériau piézoélectrique dont la face interne est placée sur la face externe de la seconde forme (13) et un film (21 ) en matériau souple isolant électrique agencé de façon à être plaqué contre la face externe de la couche (22) de matériau piézoélectrique, ledit film (21 ) en matériau souple comportant sur sa face en contact avec la couche (22) de matériau piézoélectrique une pluralité d'électrodes (31 ), chaque électrode (31 ) pouvant être excitées manière séparée par un signal de commande transmis par un conducteur (32), la surface conductrice de chacune des électrodes (31 ) étant agencée de façon à être en contact avec la surface de la couche (22) de matériau piézoélectrique de sorte que chaque électrode (31 ) forme avec la zone de la couche de matériau piézoélectrique, en regard de laquelle elle est placée, un capteur ultrasonore distinct. 1. Device for controlling a composite material structure (1 1) during its manufacture, said structure being produced in a space (15) limited by the internal face of a first form (12) and by the internal face of a second form (13), said device forming a plurality of ultrasonic sensors arranged in the vicinity of the structure, each ultrasonic sensor emitting an ultrasonic wave inside the structure (1 1) and capturing the echo returned by this structure, characterized in that it comprises a layer (22) of piezoelectric material whose inner face is placed on the outer face of the second form (13) and a film (21) of flexible electrical insulating material arranged to be pressed against the outer face of the layer (22) of piezoelectric material, said film (21) of flexible material having on its face in contact with the layer (22) of piezoelectric material a plurality of electrodes (31), each the electrode (31) being separately energizable by a control signal transmitted by a conductor (32), the conductive surface of each of the electrodes (31) being arranged to contact the surface of the layer (22) of piezoelectric material so that each electrode (31) forms with the zone of the layer of piezoelectric material, opposite which it is placed, a separate ultrasonic sensor.
2. Dispositif selon la revendication 1 , caractérisé en ce que, la couche (22) de matériau piézoélectrique étant réalisée par mise en œuvre d'un procédé de type sol-gel, elle est directement formée sur la face externe de la seconde forme (13). 2. Device according to claim 1, characterized in that, the layer (22) of piezoelectric material being produced by implementation of a sol-gel type process, it is directly formed on the outer face of the second form ( 13).
3. Dispositif selon l'une des revendications 1 ou 2, caractérisé en ce que le film (21 ) isolant électrique en matériau souple est réalisé dans un matériau polymère de type polyimide. 3. Device according to one of claims 1 or 2, characterized in that the film (21) insulating electrical flexible material is made of a polyimide polymer material.
4. Dispositif selon l'une des revendications 1 à 3, caractérisé en ce que les électrodes (31 ) sont formées par des pastilles conductrices disposées en surface, sur la face dudit film (21 ) en contact avec la couche (22) de matériau piézoélectrique, chaque électrode (31 ) étant alimentée électriquement par un élément conducteur (32) constitué par une piste conductrice disposée soit sur la face opposée du film (21 ) soit dans l'épaisseur du film. 4. Device according to one of claims 1 to 3, characterized in that the electrodes (31) are formed by conductive pads disposed on the surface, on the face of said film (21) in contact with the layer (22) of piezoelectric material, each electrode (31) being electrically powered by a conductive element (32) constituted by a conductive track arranged on the opposite face of the film (21) is in the thickness of the film.
5. Dispositif selon la revendication 4, caractérisé en ce que les pistes conductrices (32) alimentant les différentes électrodes (31 ) sont pourvues à leur extrémité d'une connectique permettant d'appliquer une tension d'excitation à chaque électrode. 5. Device according to claim 4, characterized in that the conductive tracks (32) feeding the various electrodes (31) are provided at their end with a connector for applying an excitation voltage to each electrode.
6. Dispositif selon l'une quelconque des revendications précédentes, caractérisé en ce que chaque électrode (41 ) est constituée par une pastille conductrice unique dont les dimensions sont définies de façon à ce que le capteur ultrasonore formé par cette électrode et la couche de matériau piézoélectrique émette une onde ultrasonore sensiblement plane. 6. Device according to any one of the preceding claims, characterized in that each electrode (41) is constituted by a single conductive pad whose dimensions are defined so that the ultrasonic sensor formed by this electrode and the material layer. piezoelectric emits a substantially plane ultrasound wave.
7. Dispositif selon l'une quelconque des revendications 1 à 5, caractérisé en ce que chaque électrode (61 ) est constituée par une pastille conductrice formée d'une pluralité de pastilles élémentaires (62) dont les dimensions sont définies de façon à ce que le capteur ultrasonore formé par une pastille élémentaire (62) et la couche (22) de matériau piézoélectrique émette une onde ultrasonore sensiblement sphérique ou cylindrique; les pastilles élémentaires (62) étant configurées de façon à pouvoir être commandées séparément. 7. Device according to any one of claims 1 to 5, characterized in that each electrode (61) is constituted by a conductive pad formed of a plurality of elementary pellets (62) whose dimensions are defined so that the ultrasonic sensor formed by an elementary chip (62) and the layer (22) of piezoelectric material emits a substantially spherical or cylindrical ultrasonic wave; the elementary pads (62) being configured to be separately controllable.
8. Dispositif selon la revendication 7, caractérisé en ce que les pastilles élémentaires (62) sont agencées les unes par rapport aux autres de telle façon qu'elles puissent être excitées de façon à constituer un seul capteur ultrasonore. 8. Device according to claim 7, characterized in that the elementary pellets (62) are arranged relative to each other so that they can be excited so as to constitute a single ultrasonic sensor.
9. Dispositif selon l'une quelconque des revendications précédentes, caractérisé en ce que, la seconde forme (13) constituant une masse commune, chaque électrode est configurée de façon à pouvoir être excitée par une tension d'excitation appliquée entre ladite électrode (31 ) et la masse commune. 9. Device according to any one of the preceding claims, characterized in that, the second form (13) constituting a common ground, each electrode is configured so that it can be excited by an excitation voltage applied between said electrode (31) and the common ground.
10. Dispositif selon l'une quelconque des revendications précédentes caractérisé en ce que la couche (22) de matériau piézoélectrique déposée sur la face externe de la seconde forme (13) présente une épaisseur e2 de l'ordre de plusieurs dizaines de microns. 10. Device according to any one of the preceding claims characterized in that the layer (22) of piezoelectric material deposited on the outer face of the second form (13) has a thickness e 2 of the order of several tens of microns.
1 1 . Dispositif selon l'une quelconque des revendications précédentes caractérisé en ce que le film (21 ) en matériau souple présente une épaisseur βι de l'ordre de quelques centaines de microns. 1 1. Device according to any one of the preceding claims, characterized in that the film (21) of flexible material has a thickness βι of the order of a few hundred microns.
12. Outillage de fabrication de structure (1 1 ) en matériau composite mettant en œuvre le procédé LRI, ledit outillage comportant un premier élément (12), ou moule, et un second élément (13), ou "caul plate" en vis-à-vis du premier élément, la structure (1 1 ) réalisée étant placée entre les faces internes de ces deux éléments, caractérisé en ce qu'il comporte un dispositif de contrôle par ultrasons selon l'une quelconque des revendications 1 à 1 1 , la couche (22) de matériau piézoélectrique étant formée sur la face externe de la "caul plate" (13), le film (21 ) en matériau souple étant plaqué contre ladite couche (22). 12. A tool for manufacturing a structure (1 1) made of composite material implementing the LRI process, said tooling comprising a first element (12), or mold, and a second element (13), or "flat caul" in with respect to the first element, the structure (1 1) produced being placed between the inner faces of these two elements, characterized in that it comprises an ultrasonic control device according to any one of claims 1 to 1 1, the layer (22) of piezoelectric material being formed on the outer face of the "flat caul" (13), the film (21) of flexible material being pressed against said layer (22).
EP13811547.2A 2012-12-21 2013-12-20 Reconfigurable device for checking a composite structure using ultrasound Withdrawn EP2936140A1 (en)

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