BLADE OF A STATIC BLADE OF A TURBOMACHINE

Abstract

The invention relates to a blade (13) of a static blade (11) of a turbomachine, the blade (13) comprising a blade root (21) and a blade tip, the blade (13) comprising a structure made of composite material comprising a fiber reinforcement (35) obtained by three-dimensional weaving and a matrix (37) in which the fiber reinforcement (35) is embedded, the fiber reinforcement (35) comprising strands (39) forming warp threads and weft threads of the three-dimensional weaving, the fiber reinforcement (35) further comprising unidirectional detection fibers (41) formed of an electrically conductive material. The invention also relates to a static blade (11) comprising at least one such blade (13), a turbomachine comprising at least one such static blade (11), and an aircraft comprising at least one such turbomachine. Figure for abstract: Fig. 4

Description

Title of the invention: BLADE OF A STATIC BLADE OF A TURBOMACHINE Technical field

[0001] The present application relates to the field of turbomachines. The present application relates in particular to a blade of a static blade of a turbomachine, in particular a variable-pitch blade of a static blade of a turbomachine, a static blade of a turbomachine, in particular an unducted rectifier of a turbomachine, comprising at least one such blade, a turbomachine comprising at least one such static blade, as well as an aircraft comprising at least one such turbomachine. The invention applies in particular to the unducted rectifier of a turbomachine. STATE OF THE ART

[0002] Turbomachines comprising at least one unducted propeller are known by the English terms “open rotor”, “propfan” or “unducted fan”. Such turbomachines may comprise two unducted and counter-rotating propellers (known by the English acronym CROR for “Contra-Rotating Open Rotor”) or a single unducted propeller (known by the English term “unducted single fan”) and a rectifier formed by a static vane whose blades are known by the English acronym OGV for “Outlet Guide Vane”, which is arranged downstream of the unducted propeller. Such a rectifier has the function of straightening the aerodynamic flow at the outlet of the propeller of the turbomachine. The propellers may be placed at the rear of the gas generator (or engine) so as to be of the pusher type or at the front of the gas generator so as to be of the tractor type.These turbomachines are turboprops that differ from turbojets by the use of a propeller outside the nacelle (unducted) instead of an internal fan. This makes it possible to increase the bypass ratio significantly without being penalized by the mass of the casings or nacelles intended to surround the blades of the propeller or fan.

[0003] The vanes of the rectifier are generally installed on a casing which carries the separation nozzle of the primary flow and the secondary flow circulating respectively in a primary vein and around the inlet casing. Unlike the upstream propeller of a USF type turbomachine, the vanes of the rectifier are fixed in rotation relative to the axis of rotation of the upstream propeller.

[0004] The blades of the static blading are advantageously variable pitch. For this purpose, each stator blade is pivotally mounted along an axis, each blade root being connected to a pitch change system mounted in the turbomachine. The blades with variable timing can thus be pivoted during the operation of the turbomachine. The integration zone of the blade root and the blade pivot is an area heavily constrained by the presence of numerous pieces of equipment around them.

[0005] Furthermore, in such turbomachines where a weight saving is sought, the variable-pitch blades are preferably made of a composite material comprising a fiber reinforcement embedded in an organic matrix. Thus, in recent turbomachines, large-dimension blades are increasingly frequently made of organic matrix composite materials, because these materials allow a significant weight saving with equivalent mechanical properties, or a mechanical gain for an equivalent weight, or both a weight saving and a mechanical gain. The blades of such blades are for example made by laminating two-dimensional fiber reinforcements subsequently densified by resin, or more recently by three-dimensional weaving of a single preform which will be subsequently densified.

[0006] In the context of the design and manufacture of composite material blades, it is necessary to take into account the ingestion resistance of the blade. For bird risk, certification requirements vary depending on the size of the turbomachine and in particular the diameter of the fan or propeller. These requirements impose impact conditions, i.e. a projectile mass representing a bird impacting the blade, at a certain speed, corresponding to the forward speed of the aircraft at the time of impact. It is possible in certain cases to admit a limited level of damage, which allows the aircraft either to continue its mission or flight without problem, or to land on the tarmac and be repaired. In all cases, the safety of passengers, flight crews and the populations overflown must be guaranteed. Thus, these requirements are, certainly restrictive, but absolutely essential.

[0007] In the case of admissible damage, this must be identifiable with certainty during a ground control inspection. The damage can be located either in the aerodynamic part (in the area of the vein), or at the level of the attachment (under the vein). The part under the vein is masked by a platform which reconstitutes the vein to improve the aerodynamics of the turbomachine, this part of the blading is therefore not visible without disassembly.

[0008] On conventional shrouded architectures, the design of current rotating blades does not allow any damage at the blade root before the blade breaks. The breakage thus occurs primarily in the visible aerodynamic part of the blade, which solves the problem of controlling damage to the blade.

[0009] However, a blade, rotating (fan blade, propeller) or static (OGV), in its design, can present both a naturally high resistance in its blade-forming part, due to the aerodynamic volume, manufacturing tolerances (minimum thickness) and the properties of the materials used, and a naturally low resistance in its blade root part, which is located under the vein and is therefore not visible unless disassembly is carried out. The low resistance of the blade root part results, for example, from the shape imposed by external needs (such as assembly and disassembly constraints, an external interface constraint), by the available space (generating an integration constraint), and by the dimensions and properties of the materials used (manufacturing constraints).

[0010] In this case, the critical zone, i.e. the zone in which damage can occur, for example during ingestion, is located outside the aerodynamic vein, and is thus located in an area that is not visible unless disassembly is carried out. However, such disassembly is not easy and cannot therefore be carried out regularly, for example during ground control inspection operations. Furthermore, checking for possible damage requires long and tedious non-destructive testing, such as tomography, radiography, or ultrasonic testing. Presentation of the invention

[0011] An aim of the present application is to remedy the aforementioned drawbacks, by proposing a blade of a static blade of a turbomachine, aimed at making it possible to simply detect damage during ingestion.

[0012] To this end, the invention proposes, according to a first aspect, a blade of a static blade of a turbomachine, the blade comprising a blade root and a blade tip, the blade comprising a structure made of composite material comprising a fibrous reinforcement obtained by three-dimensional weaving and a matrix in which the fibrous reinforcement is embedded, the fibrous reinforcement comprising strands forming warp threads and weft threads of the three-dimensional weaving, the fibrous reinforcement further comprising unidirectional detection fibers formed from an electrically conductive material.

[0013] Thus, thanks to the introduction of unidirectional detection fibers formed from an electrically conductive material, it is easier and faster to detect damage to the blade, or even to the static blading, in a non-visible area, more precisely under the vein. Such damage occurs for example during ingestion with an energy level that can cause damage to the static blading in the non-visible area, more precisely under the vein. For example, an area of the blade under the vein has been identified that is subject to compressive stresses, which is small and isolated, and thus very difficult to access and the damage of which is difficult to measure. The unidirectional detection fibers are thus particularly sized for this case of high-energy ingestion. The fact that the unidirectional detection fibers are formed from an electrically conductive material trically conductive also makes it possible to easily detect damage without having to disassemble the blade from the static blading following ingestion. Indeed, when an ingestion occurs with an energy level that can cause damage to the static blading under the vein, the unidirectional detection fibers are also stressed. Due to their mechanical properties, which are different from those of the strands of the three-dimensional weave, damage to the unidirectional detection fibers can occur at a predetermined energy level, which is, for example, chosen so that beyond this predetermined energy level, damage to the static blading under the vein is possible.The detection of a difference in electrical conductivity between an initial state without damage to the unidirectional detection fibers and a state following ingestion having caused damage to the unidirectional detection fibers is then possible, which allows us to conclude that there may be damage to the static vane under the vein. Thus, damage that may occur at the core, between two interfaces or at a location that is not visible under the wing can be detected via the difference in electrical conductivity. Otherwise, such damage requires a CDN passage (tomography, radiography, ultrasonic testing, etc.).

[0014] According to a second aspect, the invention proposes a static blading of a turbomachine comprising at least one blade conforming to the first aspect.

[0015] According to a third aspect, the invention proposes a turbomachine comprising a static blading according to the second aspect.

[0016] According to a fourth aspect, the invention proposes an aircraft comprising at least one turbomachine in accordance with the third aspect.

[0017] The invention is advantageously and optionally supplemented by the following characteristics, taken alone or in any of their technically possible combinations:

[0018] - The blade is a variable pitch blade.

[0019] - The strands are woven with the unidirectional detection fibers. Thus, the fa The construction is simplified. In fact, the unidirectional detection fibers are therefore co-woven at the same time as the strands to form the fiber reinforcement. Unidirectional detection fibers are thus introduced during weaving into an area which, during an impact resulting for example from ingestion, is located between a low-stress area and a high-stress area likely to suffer damage that is difficult to detect, for example under the vein.

[0020] - The unidirectional detection fibers are encapsulated in the strands, of preferably in the strands closest to an external surface of the blade.

[0021] - The unidirectional detection fibers are embedded in the most strands close to an external surface of the blade.

[0022] - The unidirectional detection fibers are maintained at each of their ex terminated by the strands. Thus, the implementation of unidirectional detection fibers is simplified and the risk of damage to the unidirectional detection fibers is reduced.

[0023] - The unidirectional detection fibers are continuous.

[0024] - Unidirectional sensing fibers are frangible. Thus, damage unidirectional sensing fibers intervene before damage to other blade components occurs.

[0025] - The unidirectional sensing fibers are configured to break at shock reaction. Thus, damage to unidirectional sensing fibers occurs at an energy level resulting from a shock, for example from ingestion.

[0026] - The unidirectional sensing fibers extend in the direction of the foot from blade to blade tip. Thus, the unidirectional detection fibers are oriented in the main direction of blade deformation during ingestion.

[0027] - Unidirectional detection fibers have an electrical conductivity su higher than that of the strands and that of the matrix. Thus, the detection of a difference in electrical conductivity, between an initial state without damage to the unidirectional detection fibers and a state following ingestion having caused damage to the unidirectional detection fibers, is facilitated.

[0028] - The unidirectional detection fibers are arranged parallel to each other others.

[0029] - The unidirectional detection fibers are arranged on the periphery of the reinforcement fibrous, preferably only on the periphery of the fibrous reinforcement. Thus, the influence of the unidirectional detection fibers on the strength of the blade is limited. Indeed, the impact is thus minimal on the definition of the blade, in particular when the unidirectional detection fibers are made of a material that allows them to withstand loads equivalent to those of the strands.

[0030] - The unidirectional detection fibers are flush with an external surface of the blade, also called dawn skin. Thus, detection is facilitated, since it is easier to measure the conductivity of unidirectional detection fibers.

[0031] - The unidirectional detection fibers are present at an external surface of dawn. Thus, detection is facilitated, since it is easier to measure the conductivity of unidirectional detection fibers.

[0032] - The external surface is delimited in the vein. Thus, detection is facilitated, from makes it easier to measure the conductivity of unidirectional sensing fibers in the vein, which is an easily accessible area.

[0033] - The unidirectional detection fibers are made of graphite. The use of graphite is particularly advantageous, because graphite is an anisotropic material with good electrical conductivity. It is therefore easier to check for breaks in unidirectional detection fibers, and therefore damage to areas of interest on the blade. Furthermore, graphite is a material that allows unidirectional detection fibers to hold loads equivalent to those of strands.

[0034] - Each unidirectional sensing fiber is integrally formed into a single piece, preferably in a single piece of graphite.

[0035] - The unidirectional detection fibers are arranged between 40% and 60% of the blade chord C. The blade chord C extends from the leading edge of the blade to the trailing edge of the blade. This area is particularly stressed during an impact on the blade, particularly during ingestion. Thus, arranging the unidirectional detection fibers in this area makes it possible to carry out detection simply, while avoiding areas that can be highly stressed during normal operation of the blade, such as the leading edge of the blade.

[0036] - The unidirectional detection fibers are arranged at least 5% of the height h of the blade, preferably between 6% and 10% of the height h of the blade. The height h of the blade extends from the blade root to the blade tip. The height h is measured radially along a radial axis Z extending radially relative to an axis of rotation X of the propeller rotor (respectively, of the fan). Indeed, this area is particularly stressed during an impact on the blade, in particular during ingestion. Thus, arranging the unidirectional detection fibers in this area makes it possible to carry out detection simply, while avoiding areas that may be deformed during normal operation of the blade, such as for example the blade tip. In addition, the area located below 5% of the height h of the blade is not accessible, being located under the vein, and therefore under a vein panel or an aerodynamic platform.

[0037] - The blade root comprises a first portion of the fiber reinforcement, the unidi fibers detection fibers being arranged in the first portion, preferably only in the first portion. This area is stressed during an impact on the blade, in particular during ingestion. Thus, arranging the unidirectional detection fibers in this area makes it possible to carry out detection simply, while avoiding areas which could be deformed during normal operation of the blade, such as for example the blade tip.

[0038] - The blade tip comprises a second portion of the fiber reinforcement.

[0039] - The fiber reinforcement is formed from a single-piece fiber preform obtained by three-dimensional or multi-layer weaving with evolving thickness. Thus, manufacturing is simplified.

[0040] - The strands comprise fibers chosen from the group of carbon fibers, glass fibers, aramid fibers and basalt fibers.

[0041] - The matrix is polymeric, preferably epoxy, bismaleimide or polyimide.

[0042] - The blade extends longitudinally from the blade root towards the blade tip.

[0043] - The static vane is an unshrouded rectifier.

[0044] - The static blading comprises a casing.

[0045] - The static blading casing comprises at least one vein panel. Thus, the aerodynamics of the static blade are improved.

[0046] - The blade foot is fixed on a clip.

[0047] - The blade root and the attachment are pivotally mounted around an axis of the blade.

[0048] - The blade extends through a vein of the static blading.

[0049] - The blade comprises a blade profile between the blade root and the blade tip, the blade profile extending into the vein.

[0050] - The blade profile extends to the tip of the blade.

[0051] - The blade has an intrados face and an extrados face extending between an edge leading edge and a trailing edge.

[0052] - The unidirectional detection fibers are flush with the intrados face or the face extrados, preferably the extrados face. This makes detection easier, since it is easier to measure the conductivity of the unidirectional detection fibers on the intrados face or on the extrados face, which are easily accessible areas.

[0053] - The turbomachine further comprises a ducted fan or a non-ducted propeller shrouded, a compression section and a turbine section, the static blading being at least one of the following bladings: a shrouded fan stator, an unshrouded propeller stator, a compression section stator, a turbine section distributor.

[0054] According to a fifth aspect, the invention also proposes a method for detecting damage in a blade according to the first aspect, comprising the following steps: - measurement of a current value of conductivity of unidirectional detection fibers, - comparison of the current value with a reference value, - when the comparison result exceeds a predetermined threshold, determination that damage to the blade has occurred.

[0055] Thus, the detection of damage is carried out in a particularly simple manner using unidirectional detection fibers.

[0056] The invention is advantageously and optionally supplemented by the following characteristics, taken alone or in any of their technically possible combinations:

[0057] - The reference value is the reference value of conductivity of unidirectional fibers detection capabilities in an initial state in which the blade does not show any damage. Thus, the reference value is reliable.

[0058] - The step of measuring the current value is preceded by a step of measuring the reference value. Thus, the reference value is obtained in a simple and reliable manner.

[0059] - The step of measuring the current value is carried out by a resistive sensor. Such Resistive sensors are used, for example, for health monitoring. For example, live monitoring is possible using such a resistive sensor.

[0060] - The step of measuring the reference value is carried out by the resistive sensor.

[0061] - The comparison step is carried out by an operating unit connected to the sensor resistive.

[0062] - The operating unit is configured to be carried on board the aircraft. Thus, live monitoring of the aircraft is possible using such an operating unit, for example during a flight phase of the aircraft.

[0063] - The resistive sensor is configured to be on board the aircraft, preferably on the dawn. Thus, live monitoring of the aircraft is possible using such a resistive sensor, for example during a flight phase of the aircraft.

[0064] - The step of measuring the current value, and preferably the step of measuring the reference value, is carried out on the ground by a user. Thus, the mass of the aircraft is limited while allowing the measurement(s) necessary to detect possible damage to be carried out simply. DESCRIPTION OF THE FIGURES

[0065] Other characteristics, aims and advantages of the invention will emerge from the detailed description below, which is purely illustrative and non-limiting, and which must be read in conjunction with the appended drawings, given as non-limiting examples and in which: - [Fig.l] is a schematic view of an example of an aircraft comprising at least one turbomachine according to one embodiment; - [Fig.2] is a schematic perspective view of an example of a USF type turbomachine comprising a single unducted propeller and a fixed blade, for example an unducted rectifier, comprising at least one blade according to one embodiment; - [Fig.3] is a schematic view, in axial and partial section of an example of a USF type turbomachine comprising a single unducted propeller and a fixed blade, for example an unducted rectifier, comprising at least one blade conforming to a embodiment; - [Fig.4] is a schematic perspective and partial view of a static blading comprising a blade according to one embodiment; - [Fig.5] represents two schematic perspective and opposite views of a blade according to an embodiment, which also represent the stresses undergone by the blade during ingestion; - [Fig.6] illustrates the main steps of a method for detecting damage in a blade according to one embodiment.

[0066] Throughout the figures, similar elements are designated by identical references. DETAILED DESCRIPTION

[0067] [Fig.l] represents an aircraft 100 comprising at least one turbomachine 1, in this example two turbomachines 1. Each turbomachine 1 can be mounted on the aircraft 100 via a pylon.

[0068] As shown in [Fig. 2], the at least one turbomachine 1 conventionally comprises at least one fan or at least one propeller 3, a compression section 5, a combustion chamber 7, a turbine section 9 downstream of the combustion chamber 7, and an exhaust casing. Furthermore, the at least one turbomachine 1 comprises at least one static (i.e. non-rotating) vane 11, whether it is a static vane 11 for stowing a fan or a propeller 3, a static vane 11 for stowing the compression section 5, or a static vane 11 for distributing the turbine section 9.

[0069] By way of example, as shown in [Fig.2] and in [Fig.3], the turbomachine 1 is a USF type turboprop comprising an unducted propeller 3, in which case the static blading 11 is an unducted rectifier and extends downstream of the propeller 3. In another example, the turbomachine 1 may be a turbojet comprising a ducted fan, in which case the static blading 11 corresponds to a ducted rectifier extending downstream of the fan.

[0070] In the present application, upstream and downstream are defined relative to the direction of flow of the gases through the static blading 11. The axis of rotation of the rotor of the propeller 3 (respectively, of the fan) is called the X axis. The axial direction corresponds to the direction of the X axis. A radial direction corresponds to a Y axis, and is a direction orthogonal to this X axis and passing through the X axis. Furthermore, the circumferential (or tangential) direction corresponds to a direction orthogonal to the X axis and not passing through the X axis.

[0071] The static blading 11 thus comprises at least one blade 13. The static blading 11 also comprises a casing 15 mounted fixedly relative to a casing 17 of the turbine bomachine 1. It is therefore non-rotating. Each blade 13 of the static blading 11 extends substantially radially relative to the X axis.

[0072] A blade 13 is thus defined relative to the axis X of the rotor associated with the static blading 2 (whether it is the axis of rotation of the fan or of the propeller 3 for a fan rectifier, the axis of rotation of the rotor of the compressor for a compression section rectifier 5 or even the axis of rotation of the rotor of the turbine for a turbine section distributor 9 on which it is intended to be mounted.

[0073] The blade 13 has an aerodynamic profile and is placed in an air flow when the turbomachine 1 is in operation. Thus, the blade 13 extends through a vein of the static blading 11, also called an aerodynamic vein.

[0074] The casing 15 of the static blading 11 carries at least one vein panel 18, which is shown in [Fig. 2]. The vein panel 18 is arranged around a blade 13, and thus separates the vein from a sub-vein area, which is not visible unless disassembly is carried out. In order to delimit the vein, the vein panel 18 extends tangentially.

[0075] Advantageously, the blade 13 has variable pitch. The blade 13 is thus pivotally mounted about an axis Y on the static blade 11. The static blade 11 thus comprises an actuating mechanism 19 making it possible to modify the pitch angle of the blade 13 of the static blade 11 in order to adapt the performance of the turbomachine 1 to the different flight phases.

[0076] As shown in [Fig.4], the blade 13 comprises a blade root 21. A line V schematically represents the separation between the vein and the sub-vein zone.

[0077] The blade root 21 is fixed on a fastener 23. The blade root 21 and the fastener 23 are configured to be pivotally mounted around an axis Y of the blade 13. Thus, the blade root 21 and the fastener 23 are pivotally mounted around the axis Y of the blade 13.

[0078] The blade 13 extends longitudinally from the blade root 21 towards a blade tip 25, along the Y axis.

[0079] The Y axis is a radial axis of the static blade 11. In other words, the Y axis extends radially relative to the X axis.

[0080] [Fig. 5] schematically represents two opposite views of the blade 13, which also represent the stresses undergone by the blade during ingestion. For example, a zone Z of the blade 13 under the vein undergoing compressive stresses has been identified, which is small and isolated, and thus very difficult to access and the damage of which is difficult to measure.

[0081] The blade 13 thus comprises a blade profile 26 between the blade root 21 and the blade tip 25. The blade profile 26 advantageously extends to the blade tip 25. Thus, the blade 13 has an intrados face 27 and an extrados face 29 extending between a leading edge 31 and a trailing edge 33.

[0082] As shown in [Fig.4], the blade 13 comprises a structure made of composite material comprising a fibrous reinforcement 35 obtained by three-dimensional weaving and a matrix 37 in which the fibrous reinforcement 35 is embedded.

[0083] Preferably, the matrix 37 is polymeric, preferably epoxy, bismaleimide or polyimide.

[0084] The fibrous reinforcement 35 conventionally comprises strands 39 forming warp threads and weft threads of the three-dimensional weaving. An example of a strand 39 forming a warp thread is shown in [Fig. 4], the other strands forming the warp threads and the weft threads being omitted in order to simplify the reading of [Fig. 4].

[0085] Advantageously, the strands 39 comprise fibers chosen from the group of carbon fibers, glass fibers, aramid fibers and basalt fibers.

[0086] The fiber reinforcement 35 is shaped from a three-dimensional woven fiber preform, before resin injection or densification by the matrix 37 and possible machining, in order to obtain a blade 13 made of composite material in accordance with the invention. By three-dimensional weaving, it will be understood that the warp threads follow sinuous paths in order to link together weft threads belonging to different layers of weft threads except for delinks, it being noted that a three-dimensional weave, in particular with an interlock weave, can include 2D weaves on the surface. Different three-dimensional weave weaves can be used, such as interlock, multi-satin or multi-veil weaves, for example as described in particular in document WO 2006 / 136755 A2 or in document WO 2020 / 089345 AL

[0087] Preferably, the fibrous reinforcement 35 is formed from a single-piece fibrous preform obtained by three-dimensional or multi-layer weaving with varying thickness.

[0088] The fibrous reinforcement 35 further comprises unidirectional detection fibers 41 formed from an electrically conductive material.

[0089] The unidirectional detection fibers 41 are arranged parallel to each other. Furthermore, the unidirectional detection fibers 41 are continuous.

[0090] The unidirectional detection fibers 41 extend in the direction from the blade root 21 to the blade tip 25.

[0091] The unidirectional sensing fibers 41 are frangible. Thus, the unidirectional sensing fibers 41 are configured to break in response to a shock, for example a shock resulting from ingestion.

[0092] Advantageously, the unidirectional detection fibers 41 are made of graphite.

[0093] Advantageously, each unidirectional detection fiber 41 is integrally formed in a single piece, preferably in a single piece of graphite.

[0094] The blade root 21 comprises a first portion of the fiber reinforcement 35. The top blade 25 comprises a second portion of the fiber reinforcement 35. Advantageously, the unidirectional detection fibers 41 are arranged in the first portion of the fiber reinforcement 35, preferably only in the first portion of the fiber reinforcement 35.

[0095] Preferably, the unidirectional detection fibers 41 are arranged between 40% and 60% of the chord C of the blade 13. The chord C of the blade extends from the leading edge 31 of the blade 13 to the trailing edge 33 of the blade 13.

[0096] Preferably, the unidirectional detection fibers 41 are arranged at least 5% of the height h of the blade 13, preferably between 6% and 10% of the height h of the blade 13. The height h of the blade 13 extends from the blade root 21 to the blade tip 25. The height h is for example measured radially along the Y axis.

[0097] Advantageously, the unidirectional detection fibers 41 are arranged on the periphery of the fiber reinforcement 35, preferably only on the periphery of the fiber reinforcement 35.

[0098] Preferably, the unidirectional detection fibers 41 are present on an external surface S of the blade 13. The external surface S is delimited in the vein. Advantageously, the unidirectional detection fibers 41 are flush with the external surface S of the blade 13. For example, the unidirectional detection fibers 41 are flush with the intrados face 27 or the extrados face 29, preferably the extrados face 29, as shown in [Fig.5].

[0099] Advantageously, the strands 39 are woven with the unidirectional detection fibers 4L

[0100] Advantageously, the unidirectional detection fibers 41 are encapsulated in the strands 39, preferably in the strands 39 closest to the external surface S of the blade 13.

[0101] Preferably, the unidirectional detection fibers 41 are embedded, for example partially embedded, in the strands 39 closest to the external surface S of the blade 13.

[0102] Advantageously, the unidirectional detection fibers 41 are held at each of their ends by the strands 39.

[0103] Preferably, the unidirectional detection fibers 41 have an electrical conductivity greater than that of the strands 39 and that of the matrix 37.

[0104] [Fig.6] represents the main steps of a detection method damage in a blade, which is advantageously the blade 13 previously described.

[0105] Such a detection method comprises, for example, the following steps: - Fold measurement of a current value of conductivity of unidirectional detection fibers, - P20 comparison of the current value with a reference value, - P30 when the result of the comparison exceeds a predetermined threshold, determination that damage to the blade has occurred.

[0106] Advantageously, the reference value is the reference value of conductivity of the unidirectional detection fibers in an initial state in which the blade does not show any damage.

[0107] Preferably, step PI 1 of measuring the current value is preceded by a step P10 of measuring the reference value.

[0108] Advantageously, step P11 of measuring the current value is carried out by a resistive sensor. Preferably, the resistive sensor is configured to be on board the aircraft, preferably on the blade. Preferably, step P10 of measuring the reference value is carried out by the resistive sensor. Advantageously, step P20 of comparison is carried out by an operating unit connected to the resistive sensor. Preferably, the operating unit is configured to be on board the aircraft. Advantageously, step P30 is also carried out by the operating unit.

[0109] Alternatively, the step P1 of measuring the current value, and preferably the step P10 of measuring the reference value, is carried out on the ground by a user, for example by means of an electrical conductivity sensor, such as a resistive sensor. Advantageously, the comparison step P20 is carried out by the user. Advantageously, the step P30 is also carried out by the user.

Claims

Claims

1. Blade (13) of a static blade (11) of a turbomachine (1), the blade (13) comprising a blade root (21) and a blade tip (25), the blade (13) comprising a structure made of composite material comprising a fibrous reinforcement (35) obtained by three-dimensional weaving and a matrix (37) in which the fibrous reinforcement (35) is embedded, the fibrous reinforcement (35) comprising strands (39) forming warp threads and weft threads of the three-dimensional weaving, the blade (13) being characterized in that the fibrous reinforcement (35) further comprises unidirectional detection fibers (41) formed of an electrically conductive material.

2. A blade (13) according to claim 1, wherein the strands (39) are woven with the unidirectional sensing fibers (41).

3. A blade (13) according to claim 1 or 2, wherein the unidirectional sensing fibers (41) are frangible.

4. A blade (13) according to any one of claims 1 to 3, wherein the unidirectional sensing fibers (41) are flush with an outer surface S of the blade (13).

5. A blade (13) according to any one of claims 1 to 4, wherein the unidirectional sensing fibers (41) are made of graphite.

6. A blade (13) according to any one of claims 1 to 5, wherein the unidirectional sensing fibers (41) are arranged between 40% and 60% of the chord C of the blade (13).

7. Blade (13) according to any one of claims 1 to 6, wherein the unidirectional detection fibers (41) are arranged at least 5% of the height h of the blade (13), preferably between 6% and 10% of the height h of the blade (13).

8. Static vane (11) of a turbomachine (1) comprising at least one blade (13) according to any one of claims 1 to 7.

9. Turbomachine (1) comprising at least one static blading (11) according to claim 8.

10. Aircraft (100) comprising at least one turbomachine (1) according to claim 9.

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