Patent Application
20230366776
This application claims the benefit of the European patent application No. 22173620.0 filed on May 16, 2022, the entire disclosures of which are incorporated herein by way of reference.
The invention relates to an arrangement including a fiber-reinforced composite component or composite assembly. Further, the invention relates to an aircraft or spacecraft comprising at least one such arrangement, to a method of producing an arrangement that includes a fiber-reinforced composite component or composite assembly, and to a method of monitoring the structural integrity of a fiber-reinforced composite component or composite assembly.
Although the invention may be useful in connection with various components or component assemblies made from composite materials in many fields of technology, the invention and the underlying problem will be explained in the following in exemplary manner with reference to aircraft or spacecraft production, more particularly in connection with implementing structural joints in aircraft or spacecraft structures, but without limiting the invention to that effect.
In the context of producing aircraft structures from fiber-reinforced composite materials such as fiber-reinforced synthetic materials, several techniques of joining parts of a composite component or components forming a composite assembly to each other have already been proposed, including riveting and adhesive bonding. Welding of components comprising thermoplastic has also been proposed.
Riveting requires a step of drilling holes for rivets and a step of inserting the rivets. Also, rivets add weight to the structure and may require laminate thicknesses to be selected and designed accordingly, which also may lead to an increase in the structural weight and to an increase in cost due to higher workload and need for additional parts, compared to bonding or welding.
As a further way of implementing a structural connection, stitching of reinforcing materials, e.g., dry reinforcing fiber plies, has already been suggested. As an example, dry reinforcing fiber plies, used to form one or more composite parts, may be stacked and connected by stitching through the plies, e.g., for out-of-plane reinforcement of a composite part. Then, the dry fiber plies may be infused with resin, e.g., using VAR™ or vacuum-assisted resin transfer molding, and cured. Various stitching patterns, needle configurations and types of needle operation are conceivable. For example, a stitching head using two needles may be used. Further, for instance, one needle may be aligned vertically and the other may be angled. Alternatively, both needles may be inclined or one of the needles may operate horizontally. Typically, during stitching, loops are created that tie the composite plies together with a certain clamping action. A structural joint involving an adhesive connection via the cured matrix can be effectively strengthened in this manner. Also, another useful effect of stitching is that the manufacturing process can be supported and facilitated by fixation of a pre-form, for example of a stringer pre-form on plies that are provided to form a skin.
Based on previous work on stitched composites, this technique appears promising, also regarding the mechanical behavior of composite components or assemblies produced in this manner.
It would, however, be desirable to be able to monitor the structural integrity, or structural “health,” of a stitched component or component assembly, particularly the health or integrity of stitched seams, in a manner that is reliable and can be implemented in an economical way, in particular within complex structures including a large number of stitched connections.
In view of this background, the problem to be solved by the present invention is to provide a way of monitoring the structural integrity of a composite component or assembly including a stitched seam, which can be implemented in an economical manner.
Accordingly, an arrangement is proposed which includes:
There is further proposed an aircraft or spacecraft which comprises at least one such arrangement, wherein the composite component or composite assembly in particular forms part of an aircraft or spacecraft structure.
Still further, the invention provides a method of producing an arrangement including a fiber-reinforced composite component or composite assembly, the method comprising:
Moreover, the invention provides a method of monitoring the structural integrity of a fiber-reinforced composite component or composite assembly including a seam formed by stitching using a yarn, wherein the method comprises monitoring the structural health status of the seam, including:
An idea underlying the present invention is to implement and/or strengthen a joint by means of the seam wherein the joint is more lightweight than a riveted joint and at the same time can be monitored in an economical and effective manner. The region of the joint can be formed with reduced weight because stress concentrations tend to be comparatively small in stitched joints due to the large number of stitches, hence the material layer thicknesses may be comparatively small in the area of the joint. Use of the conductive stitching yarn as a distributed sensor advantageously makes it possible to avoid separate sensors for structural health monitoring of the seam as well as the effort and cost involved for installation and maintenance of such separate sensors, and thus may enable structural health monitoring at a large number of stitched joints in economical manner, for example throughout an entire structure such as, e.g., an aircraft structure.
Furthermore, monitoring of structural integrity or structural health using the invention makes it possible to capture, via the sensor function of the yarn, both tearing mode damage as well as rupture mode damage in the seam at the joint. The invention makes it possible to detect impairment of the integrity of the yarn, which may, for instance, include damage mechanisms of:
The invention does not only enable detection of a full rupture of a connection at the stitched seam, but additionally, for example, initial damage beyond limit load capability and well within the damage tolerance domain may advantageously be detected, too.
Furthermore, the invention, in particular, may enable the detection of formation and/or spreading of damage over longer periods of time such as, e.g., the operational life of a component or assembly, for example a component or assembly of an aircraft or spacecraft structure.
Accordingly, the invention may contribute to the usefulness of stitched composites in complex structures. In particular, the invention may contribute to implementing an extent or amount of stitching which, while preferably being as small as possible to reduce cost, workload and disturbance of the underlying fiber formations, makes it possible to effectively prevent excessive spread of damage and at the same time enables reliable detection of the damage, in particular once the damage becomes significant.
In accordance with a development, the monitoring device is adapted to detect or measure an ohmic resistance and/or impedance of a portion of the yarn which includes the section of the yarn forming the seam or part thereof. In this way, the integrity or health of the yarn and thus of the seam formed using the yarn can be evaluated in a relatively simple manner.
In particular, the monitoring device may be adapted to send a constant electrical input signal or a time-varying electrical input signal. For example, the signal may be a constant voltage input signal or a time-varying voltage input signal.
In a further development, the monitoring device may be adapted to provide the input signal at intervals or within continuous time periods or continuously during the operational life of the composite component or composite assembly. In this way, an indication regarding the health status of the seam can be obtained during the operational life of the component or assembly.
For instance, the monitoring device may be configured so as to enable to send the input signal as well as to receive and evaluate the response signal when a device containing the component or assembly is being inspected, e.g., during routine inspection of an aircraft, for example during pre-takeoff inspection. In this manner, in case the monitoring device indicates a possible damage or incipient damage at a seam, appropriate action can be taken by maintenance staff, such as visual inspection of the seam. Further, the monitoring device may, for example, be used in predictive maintenance to trigger inspection. Planned inspections could thereby be reduced significantly.
In particular, within the seam, the yarn has a function of supporting mechanical loads as well as a function of an integrated structural health sensor device. In this manner, the yarn may be used as a multi-functional yarn. Effort and cost for additional, individual sensors for structural health monitoring can be avoided.
In particular, the seam forms part of a mechanically load-bearing structural joint. Further, in particular, the seam may be configured to strengthen the structural joint and/or to improve or enable damage-tolerant behavior of the joint, e.g., in the manner of so-called selective stitching, for example in infused-type shells such as fuselage shells. The economical way of monitoring the structural integrity of the seam afforded by the invention is particularly advantageous in case of structural seams, which may have to transmit considerable load. The invention may make it possible to detect a damage in such joints when the damage becomes significant.
The yarn may in some preferred developments comprise a fiber filament material that is of the same type as a filament material of the reinforcing fiber formation sections. For instance, the filament material may be carbon fiber filaments. In other useful developments, however, the fiber filament material of the yarn may differ from that of the reinforcing fiber formation sections.
In a development, the yarn comprises load-bearing electrically conductive filaments. In particular, the yarn may comprise carbon fiber filaments, for example carbon fiber filaments of the same type as those of the reinforcing fiber formation sections. Already such a yarn may yield sufficient conductivity to enable health monitoring, e.g., by a trip-wire type function.
Alternatively, the yarn may be formed from a carbon nanotube-based material, such as Tuball™ available from the company Conyar. Such a yarn may exhibit specific conductive properties that change with elongation.
In some variants, the electrically conductive filaments or the carbon nanotube-based material may form a load-bearing yarn core.
In a development, the yarn comprises a load-bearing yarn core as well as an electrically conductive layer provided on the yarn core. Different portions of the cross-section of the yarn may in this manner be adapted to a mechanical and electrical function, respectively.
In a development, the load-bearing core of the yarn may comprise glass fibers or carbon fibers. A yarn having such a core can sustain considerable loads.
In other developments, the load-bearing core of the yarn may comprise fibers from a polymeric material such as Vectran™ fibers, available from the company Kuraray, or Dyneema® fibers, e.g., available from DSM. Fibers e.g., from Vectran™ or Dyneema® are more ductile than, for instance, glass fibers.
In particular, the electrically conductive layer provided on the yarn core comprises carbon nanotubes. Such a conductive yarn may be highly stretchable and durable, and therefore can be particularly well-suited for forming a seam and monitoring the status thereof. The carbon nanotubes may in particular be deposited as a coating on the load-bearing yarn core.
For example, in some implementations, the electrically conductive layer may be formed as a coating made with a carbon nanotube-based material commercially available under the brand Tuball™ from the company Conyar. Tuball™ graphene coating could be used to enable sufficient conductivity along the length of the yarn. The conductive properties obtained may change with yarn elongation.
It may be preferable to provide the electrically conductive layer on the yarn core in cases in which the load-bearing yarn core is not electrically conductive or has insufficient electrical conductivity, in particular in case of a core from glass fibers or polymeric fibers, e.g., Vectran™ or Dyneema®.
In a further development, the yarn furthermore comprises an electrically isolating outer coating. The isolating outer coating may be provided, for example deposited, on an outer side of the conductive layer, or on an outer side of the yarn core in case the yarn core is electrically conductive and there is no electrically conductive layer on the yarn core. In this manner, undesired electrically conductive contact with other yarns, possibly other electrically conductive yarns or electrically conductive filaments, such as carbon fiber filaments, of the reinforcing fiber formations, which might lead to undesired electric currents and current loss, can be prevented. This may help to further improve the reliability of the structural health monitoring at least in some implementations. Providing the yarn with the electrically isolating outer coating may be preferable in particular if the reinforcing fiber formation sections are made using carbon fibers to form a carbon fiber reinforced synthetic substrate.
In particular, the electrically isolating outer coating may be formed with an electrically isolating epoxy resin.
In further developments, the transverse dimension, e.g., diameter or thickness, of the electrically conductive yarn core or of the electrically conductive layer is selected in such a manner as to enable an electrical conductivity along the length of the yarn and an outward electrical insulation in the transverse direction. In particular, the transverse dimension is configured such that electrically conductive contact of the yarn to electrically conductive fibers such as carbon fibers of the stitched reinforcing fiber formation sections and resulting current loss and/or short circuits are prevented while an interior portion of the cross-section of the yarn is conductive and enables the monitoring function.
In accordance with a development, the monitoring device comprises at least one electronic circuit, in particular implemented using at least one semiconductor device or a plurality of semiconductor devices. In this manner, the generation of the input signal as well as the receipt and evaluation of the response signal may be performed in a reliable, space-saving and rapid manner.
In an advantageous improvement, the seam is crossed by at least one further seam, wherein the at least one further seam is formed at least in part by stitching using a further yarn, the further yarn being electrically conductive along a length thereof. In particular, the yarn and the further yarn may be of the same type. Hence, regarding the type of the further yarn, reference is made to the explanations above for the yarn. In this improvement, the further yarn can be used for monitoring the structural integrity of the further seam in the same manner as described above for the seam. The crossing seams and corresponding conductive yarns make it possible to determine the location of a possible damage, if present, with increased accuracy. Identifying the damaged spot may thus require even further reduced effort when inspecting the component or assembly in detail. In particular, in case the damage event is captured at substantially the same time, the crossing conductive yarns can make it possible to correctly locate the damage with a high probability.
Furthermore, the crossing seams formed using the yarn and the further yarn may advantageously be used to detect the extent of a damage, in particular a crack and/or to detect a growth rate of the damage, in particular of the crack.
The seam and the further seam may, in an improvement, extend one below the other on different levels without direct contact of the yarn and the further yarn. This can help to avoid electrical contact of the yarns and undesired current from one yarn to the other. Alternatively or additionally, one or both of the yarn and the further yarn may comprise an electrically isolating outer coating as described above.
In a further development, the monitoring device may be configured to send an electrical input signal along at least the section of the yarn and a further electrical input signal along at least the section of the further yarn in a temporally offset manner. This may further help to avoid undesired electric interaction of the yarns.
In particular, the first and second reinforcing fiber formation sections may form part of different composite components joined to each other at the seam to form the composite assembly, or the first and second reinforcing fiber formation sections may form part of the same composite component within which the seam is implemented.
In particular, the reinforcing fiber formation sections and the conductive yarn or yarns may be embedded in a synthetic matrix material. The matrix material may preferably be a curable matrix material, for example an epoxy resin.
In particular, if the yarn comprises an electrically isolating outer coating, the electrically isolating outer coating is preferably adapted to be compatible with the matrix material. In case the yarn is provided with the electrically conductive layer as its outermost layer, this layer may preferably be formed to be compatible with the matrix material. If the yarn is formed without conductive or isolating layer, the yarn core or yarn base material may preferably be selected to be compatible with the matrix material.
Further, in some developments, the first and/or second reinforcing fiber formation sections may comprise carbon fibers. One or more further reinforcing fiber formation section(s), provided as part of the component or assembly, also may, in particular, comprise carbon fibers.
In variants including a first and/or second reinforcing fiber formation section comprising carbon fibers, preferably, the yarn is provided with the electrically isolating outer coating.
In further developments, the first and/or second reinforcing fiber formation sections may comprise glass fibers. One or more further reinforcing fiber formation section(s), provided as part of the component or assembly, also may in particular comprise glass fibers.
In some variants in which the yarn is used to stitch through fiber formation sections made from glass fibers, the electrically isolating outer coating of the yarn may be omitted.
In a development, the composite component or composite assembly forms part of an aircraft or spacecraft structure. The lightweight connection by stitching and the economical monitoring of the structural integrity thereof afforded by the invention are particularly advantageous for such structures. Still, the invention may in further developments be applied to structures other than aircraft or spacecraft structures.
In a preferred development, the composite assembly is formed as a shell assembly comprising a stringer coupled to a skin, wherein one of the first and second reinforcing fiber formation sections forms part of the stringer, in particular of a stringer foot thereof, and another one of the first and second reinforcing fiber formation sections forms part of the skin. As commercial aircraft are often large and may comprise a considerable number of stringers joined to a skin, the invention in this case contributes to enabling the use of a lightweight stitched connection at those joints which also can be monitored in a reliable and economical manner.
In a development, the shell assembly further comprises a frame or a segment of a frame, wherein the further seam is formed by stitching through a reinforcing fiber formation section forming part of the frame or segment, in particular of a frame foot thereof, using the further yarn. In this manner, a connection of the frame to the skin can be implemented and the structural health thereof can also be monitored in economical manner, and further, within the shell assembly, the location of a possible damage can be established with increased accuracy based on the crossing seams and their yarns.
According to a further development, the shell assembly may comprise a plurality of stringers as well as a plurality of frames extending transverse to the stringers, wherein each of the frames and stringers is coupled to the skin using at least one seam each formed using at least one conductive yarn. In this manner, at least one such seam on each of the stringers and frames can be monitored with respect to the structural integrity thereof.
In particular, in a development of the method of producing an arrangement, the method may comprise providing the reinforcing fiber formation sections in the form of dry fiber formation sections, in particular, dry plies of reinforcing fiber textile.
In a further development, the method of producing an arrangement may comprise infiltrating the stitched first and second reinforcing fiber formation sections with resin, in particular, by resin-transfer molding, for example by vacuum assisted resin transfer molding.
In particular, the first and second fiber formation sections may be stitched to each other to form a preform, or the first and second fiber formation sections may each form part of different preforms.
In a development of the method of monitoring the structural integrity, the method comprises detecting over-straining and/or rupture of the yarn within the section that forms at least part of the seam.
In particular, the method of monitoring the structural integrity may comprise monitoring the electrical resistance or impedance of the section of the yarn that forms at least part of the seam.
In a further development of the method of monitoring the structural integrity, the electrical input signal is sent, and the response signal is received and evaluated, at intervals or during continuous time periods or continuously during the operational life of the composite component or composite assembly. For instance, the input signal may be sent and the response signal received and evaluated during routine inspection, e.g., pre-takeoff inspection, of an aircraft. In further developments, the input signal may be sent and the response signal received and evaluated during active flight, e.g., repeatedly.
The improvements, enhancements and developments of the present invention may be arbitrarily combined with each other whenever this makes sense. Moreover, other possible enhancements, implementations and developments of the present invention comprise combinations of features of the invention which have been described above or will be described in the following in relation to the detailed description of embodiments, even where such a combination has not been expressly mentioned.
In particular, the improvements, enhancements and developments of the invention described above may be applied in analogous manner to each of the arrangement, the aircraft or spacecraft and each of the methods proposed herein.
The invention will be explained in the following with reference to the schematic figures of the drawings which illustrate embodiments of the invention. Herein:
The enclosed drawings are intended to illustrate embodiments of the invention so that the invention may be further understood. The drawings, in conjunction with the description, are intended to explain principles and concepts of the invention. Other embodiments and many of the advantages described may be inferred from the drawings. Elements of the drawings are not necessarily drawn to scale.
Elements, features and components which are identical or which have the same function or effect have been labeled in the drawings using the same reference signs, except where explicitly stated otherwise.
The aircraft 100 comprises a structure made at least in part from fiber-reinforced composite materials, in particular from one or more carbon or glass fiber-reinforced synthetic material(s). An exemplary structural fiber-reinforced composite assembly, which forms part of the structure of the aircraft 100, is a shell assembly 111, illustrated in
In
Production of the composite assembly 2 of
The first and second fiber formation sections 3, 4 are stitched to each other using a yarn 30 along a seam 25, so as to connect the sections 3, 4, in particular in combination with one or more further seam(s). Further, additional fiber formation sections, not illustrated in the Figure, may be connected to the first and second fiber formation sections 3, 4 in this process if desired. The stitching through the fiber formation sections 3, 4 along the seam 25 may be carried out in automated manner, e.g., using a stitching head, and using two needles for example. The stitching head may be carried and manipulated e.g., by a robot or robotic arm.
In
After completion of the stitching process, the dry fiber formation sections 3, 4 can be infiltrated with curable resin, or a preform assembly comprising the sections 3, 4 can be infiltrated with the resin, for example using VAR™ or vacuum assisted resin transfer molding. Subsequently, curing is performed, e.g., using heat and/or pressure.
By the seam 25, the load-bearing structural joint of the skin 10 and stringer 20 is strengthened. In case the joint is damaged, the stitched seam 25, in the manner of so-called selective stitching, effectively helps to prevent excessive spreading of such damage and thus enhances the damage tolerance of the joint. Conventional “crack-stoppers,” such as rivet bolts, can be avoided.
In the arrangement 1, the seam 25 connecting at least the fiber formation sections 3 and 4 is formed using a yarn 30, which is electrically conductive along its length.
The yarn 30 used in the embodiment of
A further, modified yarn 30′ is displayed in
Another yarn 30″ is illustrated in
Preferably, if the fiber formation sections 3, 4 comprise electrically non-conductive fibers such as glass fibers only, yarn 30 without outer insulating coating may be used, or alternatively, a yarn corresponding to the electrically conductive core 301 of
In case the isolating outer coating 303 is provided, the material of the coating 303 is preferably formed so as to be compatible with the matrix material used to infuse the fiber formation sections 3, 4. If the core 301 or the layer 302 forms the contact surface of the yarn to the matrix, preferably the core 301 or layer 302 is chosen such as to be sufficiently compatible with the matrix material, regarding the material of the core 301 or layer 302.
The yarn 30, 30′ or 30″ acts as a multi-functional yarn which, in the composite assembly 2, supports mechanical loads introduced into the seam 25, and, beyond this, is used as an integrated, distributed structural health sensor device for monitoring the health status of the seam 25.
The monitoring device 45 comprises, in the embodiment of
Furthermore, the monitoring device 45 comprises an indicator 31 for the stringer foot yarn status of the yarn 30 at the seam 25, as well as an impedance meter 32 for measuring impedance over the stitched yarn length section 37 along the seam 25 at the stringer foot. The indicator 31 in
Accordingly, the monitoring device 45 is coupled to the yarn 30 in a manner which enables the monitoring device 45 to send an electrical input signal through the yarn 30 extending, via the seam 25, between the positive and negative terminals of the voltage source 40, and hence also along the section 37 of the yarn 30 that forms part of the seam 25. For example, the electrical input signal may a constant DC voltage. A response signal is received on the yarn 30 via the indicator 31, indicating current through the yarn 30. Further, the response of the section 37 to the input signal may be detected using the impedance meter 32 connected via a first connecting line 41 to the yarn 30 at a first location 35 close to one end of the seam 25 and connected via a second connecting line 42 to the yarn 30 at a second location 36 close to the other end of the seam 25.
In the situation shown in
While in
As an alternative to sending a constant electrical input signal in the form of a constant DC voltage, in a variant, the monitoring device 45 may be adapted to provide an electrical input signal varying over time. For instance, an intermittent DC voltage signal may be sent along the yarn 30, in order to monitor the status of the yarn 30 at regular or irregular intervals. In other examples, an AC voltage signal may be sent along the yarn 30, e.g., a sinusoidal signal. The AC voltage signal may be sent continuously or intermittently.
The monitoring device 45 may be used to provide the electrical input signal continuously during the operational life of the assembly 2. Yet, in a preferred variant, the monitoring device 45 is used at intervals during the operational life of the assembly 2, or during periods of time, to monitor the structural health of the seam 25, for example during routine inspection of the aircraft 100, e.g., during pre-takeoff inspection or “walk-around.” If the status indicator 31 or the impedance measurement by the impedance meter 32 indicates a resistance or impedance that is higher than expected for an undamaged yarn, the seam 25 can be inspected by staff, e.g., visually, in order to determine the cause thereof and the location and extent of damage. Intermittent or continuous sending of input signals and receipt as well as evaluation of response signals could in a variant be performed during flight. The monitoring device 45 may be used to implement predictive maintenance.
In
Using the arrangement 1 schematically displayed in
In the following, some types of damage will be described with reference to
In detail 33a in
Both the stretching and the contraction, shown at 33a, with the length increased by ΔL and decreased yarn diameter, lead to an increase in electrical impedance ΔZ in this yarn 30, which can be measured. In this manner, the yarn 30 itself functions as an integrated sensor, in addition to the structural function of the yarn 30. The yarn 30 is thus multi-functional.
Due to the changes in diameter and the elongation within the gap, the yarn status indicator 31a, schematically shown again as a light bulb, detects reduced current by emitting reduced light. Also, the impedance meter 32a indicates increased impedance.
In
In
In addition to the elements 31, 32, 40, 41, 42 of the monitoring device 45 of
In
In the same manner as explained above, the functions of the status indicator 61 and impedance meter 62 preferably are implemented using at least one electronic circuit, in particular using at least one semiconductor device, not shown in the figures. For example, the functions of the complete monitoring device 75 may be implemented using at least one electronic circuit. The required voltage could be provided by an appropriate supply line, replacing the schematic voltage source 40.
Thus, in
The arrangement 1′ enables monitoring of the structural integrity of seams 25, 55 extending in two different directions, substantially transverse with respect to each other. If a damage or rupture is indicated for a seam 25 along the stringer foot, or along a stringer foot of one of several stringers 20, determining the location along the stringer 20 in question is facilitated in the arrangement 1′ of
Moreover, for instance, several additional seams 55 crossing seam 25 may be used to detect the extent of a damage, in particular of a crack, and/or to detect a growth rate or spreading rate of such damage, by performing the monitoring continuously or at appropriate intervals.
Each seam 25 or 55 may be implemented using one or more conductive yarns 30, 30′, 30″ or 60, 60′, 60″ respectively, as a stitching yarn or stitching yarns only. Alternatively, it is conceivable to use the yarn 30, 30′, 30″ or 60, 60′, 60″ in combination with other, static, non-conductive stitching yarns in the seam 25 or 55.
Input signals may be sent along the yarn 30, 30′ or 30″ and 60, 60′ or 60″ in a temporally offset manner, in order to precisely separate the responses obtained. Additionally or alternatively, the yarns 30′, 60′, 30″, 60″ provided with the isolating coating 303 may be used to implement the seams 25, 55 or at least one of them, in order to electrically separate the seams 25, 55. Further, alternatively or additionally, the yarns 30, 30′ or 30″ and 60, 60′ or 60″ may run transversely to each other, as shown in
Even though in
The assemblies 2, 2′ may each be considered components of the aircraft 100. Yet, the present invention is applicable to other components, smaller or larger than the shell assembly 111, in an aircraft or spacecraft structure, and to components or component assemblies in other fields of technology. More specifically, the assembly 2 or 2′ may form part of the fuselage 101, such as in the form of the shell assembly 111, or alternatively may form part of another shell assembly, that for instance forms part of one of the stabilizers 105, 106 or of a wing 102.
The embodiments described above with reference to
In addition, the embodiments described above with reference to
The monitoring devices 45, 75 of various assemblies 2, 2′ of the aircraft structure may be coupled in suitable manner, and health status data obtained using the sensing yarns 30, 30′, 30″, 60, 60′, 60″ throughout the aircraft 100 may be collected and processed, e.g., within the aircraft 100, by a data collection and processing device, not shown in the figures. The data collection and processing device may be configured to provide a summary on the health status of the aircraft structure and/or a warning in case of suspected damage to flight staff or maintenance staff, e.g., via a network and a handheld device such as a laptop or smartphone. The summary or warning may be displayed in textual and/or graphical manner using a graphical user interface, including, for example, an indication of the approximate location or area of possible damage.
In all embodiments described above, the composite assembly 2, 2′ can comprise fiber formation sections 3, 4 or 3, 4, 5 including carbon fibers, which are infiltrated by a curable resin such as, e.g., epoxy resin, followed by curing. Therefore, the skin 10, the stringer 20 and the frame 50 are formed in these embodiments as elements from carbon fiber-reinforced synthetic material or CFRP (carbon fiber-reinforced plastic) elements. Alternatively, the formation sections 3, 4 or 3, 4, 5 may include glass fibers infiltrated by the curable resin, followed by curing, and in this case, the skin 10, stringer 20 and frame 50 may be formed as GFRP (glass fiber-reinforced plastic) elements.
With the invention, in particular the arrangements 1, 1′ as well as the methods of the embodiments described hereinabove, at least one or more the following advantages may be obtained:
Although the invention has been completely described above with reference to preferred embodiments, the invention is not limited to these embodiments but may be modified in many ways.
For instance, the invention may be useful not only in the field of aircraft or spacecraft, but also in other fields involving composite structures, such as, for example, automobile bodies, wind power plants, or pressurized tanks or vessels.
While at least one exemplary embodiment of the present invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the exemplary embodiment(s). In addition, in this disclosure, the terms “comprise” or “comprising” do not exclude other elements or steps, the terms “a” or “one” do not exclude a plural number, and the term “or” means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority.
| Number | Date | Country | Kind |
|---|---|---|---|
| 22173620.0 | May 2022 | EP | regional |
