Method and device for repairing elements made of composite material

Abstract

The present invention relates to a method and apparatus for repairing an element made of composite material, the method comprising infusing resin (300) into an internal damaged region (101) of an element (100) made of composite material, wherein the method further comprises: drilling at least one first non-penetrating hole (200a) and at least one second non-penetrating hole (200b) in the element (100) made of composite material, each of the non-penetrating holes (200) extending from a face of the element (100) made of composite material to the internal damaged region (101), and infusing resin (300) through at least one first non-penetrating hole (200a) until the resin (300) at least fills the internal damaged region (101) of the element (100) made of composite material. The method includes applying vibration to the element (100) made of composite material at a given frequency.

Description

Technical Field

[0001] The present invention relates to a method for repairing components made of composite materials, and particularly to a method for repairing aircraft parts or components made of thermosetting composite materials.

[0002] The present invention also relates to apparatus for repairing components made of composite materials, and in particular to apparatus intended for repairing aircraft parts or components made of thermosetting composite materials.

[0003] The apparatus and method of the present invention are intended for repairing damaged structural parts or components of an aircraft, thereby allowing the mechanical strength of such parts or components to be restored to their original design requirements.

[0004] This invention is preferably applicable to the manufacture and maintenance of composite parts / components used in transportation applications such as aircraft. Background Technology

[0005] Composite materials used to form parts or components of aircraft often suffer internal damage due to various reasons, such as collisions with objects.

[0006] These internal damages cannot be detected through visual inspection of the aircraft. However, internal cracks or damage can be detected using non-destructive methods, such as ultrasonic testing.

[0007] Internal cracks or damage in composite components of an aircraft can affect structural performance. Therefore, it is crucial to detect and repair these internal damages.

[0008] Currently, bonded repair involves removing the damaged layer from the area by machining the surface around the damage into a stepped or beveled shape using grinding or milling processes. The length of the stepped portion is typically between 8 mm and 12 mm, and the bevel ratio is usually less than 1:20. Wet layup repair methods, thermal bonding repair methods, or pre-cured patch repair methods can be used to apply the repair patch to the parent structure.

[0009] Wet lay-up repair involves impregnating a dry fiber fabric with a laminating resin and then applying it to the cured composite part.

[0010] Thermal bonding repair uses pre-impregnated composite materials and adhesive films for bonding and repair.

[0011] For wet layup repairs and thermally bonded miter repairs, the repair layer is cut to precise dimensions to allow for the installation of the repair laminate while achieving a defined contact overlap length with the original laminate along the stepped or miter surface. This overlap length is typically approximately 8 mm to 12 mm.

[0012] In these methods, a curing cycle is applied to allow the repair material to harden. Additionally, vacuum pressure must be applied using a vacuum bag to solidify the repaired area.

[0013] Airlines widely use thermal bonding and wet layup repair for repairing thermosetting composite parts. However, the limited storage and shelf life of prepreg composite repair materials used for thermal bonding under certain temperature conditions is considered a major drawback of this repair method. Furthermore, for wet layup repair, controlling the ratios of different components used to prepare the repair resin and the ratio used for impregnation with dry fabric can be difficult. Additionally, in most applications, the material properties of the repair material are lower than those of the part being repaired because the fiber and resin materials, as well as the curing process, differ from the base material.

[0014] Another drawback of existing bonding repair methods, including heat-bonded and wet-layup repairs, is the relatively long time associated with completing the bonding repair. The processing of the damaged layer is the most time-consuming stage and carries the risk of creating new damage. Another time-consuming step is related to the rigorous preparation procedures for the repair layer. Furthermore, the positioning of the uncured layer must be precise to achieve minimal overlap along the edges of the layers. Summary of the Invention

[0015] In order to provide a solution to the problems mentioned above, the present invention relates to a method and apparatus for repairing components made of composite materials.

[0016] Methods for repairing components (or parts) made of composite materials include: after detecting internal damaged areas (pores or delaminated material) within the component made of composite materials, injecting resin into the internal damaged areas of the component made of composite materials.

[0017] Methods for repairing components (or parts) made of composite materials include:

[0018] – Drill at least one first non-penetrating hole (preferably having a smaller diameter, for example, about 2 mm) and at least one second non-penetrating hole (preferably having a smaller diameter, for example, about 2 mm) into an element made of composite material, each of the non-penetrating holes extending (at least) from one face of the element made of composite material to the internal damaged area; and

[0019] - Resin is injected from at least one first non-penetrating hole until the resin fills at least a portion of the internal damaged area of ​​the element made of the composite material. Preferably, the injected resin fills both the internal damaged area and the non-penetrating hole.

[0020] In a novel manner, the method involves applying vibrations at a given frequency to an element made of a composite material.

[0021] As specified above, no machining removal operations are required on the component or part made of composite material to be repaired. The load-bearing capacity of the component made of composite material is restored by means of resin infusion, which is applied by injecting resin through non-through holes (non-penetrating holes), thereby reducing the structural impact of these holes on the structural integrity and load-bearing capacity of the component made of composite material.

[0022] Furthermore, applying vibration to components made of composite materials promotes and enhances the flow of resin within the internal damaged areas of the components. Additionally, by applying vibration to the components made of composite materials, any gas bubbles contained within the internal damaged areas are facilitated to escape and are not trapped in the resin during curing.

[0023] Applying vibration to components made of composite materials can include using mechanical devices that directly impact or shake the components made of composite materials.

[0024] Applying vibration to a component made of composite material can (as an alternative to and supplement to the vibration mentioned in the preceding paragraph) include applying a varying vacuum at at least one second non-through hole.

[0025] According to a preferred embodiment of the invention, the vibration is applied at a frequency value between 0.5 and 1.5 times the normal frequency mode corresponding to the element made of the composite material. This value typically corresponds to frequency values ​​included between 20 Hz and 1000 Hz.

[0026] Methods for repairing components (or parts) made of composite materials may include heating the resin before infusing it into the internal damaged areas of the component. This operation can reduce the viscosity of the resin, thereby facilitating the infusion process.

[0027] The method may also include heating the resin after it has been infused into the internal damaged area of ​​a component made of composite material. This step can help maintain a specific infusion temperature and / or accelerate the curing of the resin.

[0028] In the case where only one side of an element made of composite material is accessible, at least one first non-through hole and at least one second non-through hole may extend from the same face of the element made of composite material at least to the internal damaged area.

[0029] Alternatively, when both sides of the component made of composite material are accessible, at least one first non-penetrating hole preferably extends from the first face (inlet side) of the component made of composite material at least to the internal damaged area, and at least one second non-penetrating hole extends from the second face (outlet side) of the component made of composite material at least to the internal damaged area. This embodiment allows resin to be infused onto one face (inlet side) of the component made of composite material, and ultimately a vacuum is applied to the other face (outlet side) of the component made of composite material. Therefore, this facilitates resin infusion when both faces are accessible for the repair method.

[0030] Each first non-through hole and each second non-through hole can be distributed such that the projection of each first non-through hole onto the second surface of the element made of the composite material does not coincide with the projection of any second non-through hole onto the second surface of the element made of the composite material, and the projection of each second non-through hole onto the first surface of the element made of the composite material does not coincide with the projection of any first non-through hole onto the first surface of the element made of the composite material. Therefore, the non-through holes are distributed such that the second non-through holes do not face the first non-through holes.

[0031] As already described, the present invention also relates to an apparatus for repairing components made of composite materials, the apparatus being configured to perform the method for repairing components made of composite materials as described above.

[0032] The apparatus for repairing components made of composite materials according to the present invention comprises:

[0033] o A resin reservoir configured to contain resin to be infused into an internal damaged region of an element made of composite material through at least one first non-through hole;

[0034] o A discharge mask, connected to an outlet guide, the discharge mask including a housing configured to define a receiving portion between at least one second non-through hole and the outlet guide, the receiving portion being isolated from a resin reservoir, wherein the receiving portion is configured to receive resin flowing out from at least one second non-through hole; and

[0035] o A device used to generate vibrations to be transmitted to an element made of composite materials.

[0036] According to an embodiment of the present invention, a device for generating vibrations to be transmitted to an element made of composite material includes a vibration module configured to generate mechanical vibrations to be transmitted to the element made of composite material.

[0037] As an alternative to or supplement to the vibration module mentioned in the preceding paragraph, a device for generating vibrations to be transmitted to an element made of composite material may include a vacuum percussion module configured to establish a pulse pattern that controls the application of a vacuum to the interior of the receiving portion.

[0038] The apparatus for repairing components made of composite materials preferably includes a heating module configured to heat the resin contained in a resin reservoir.

[0039] The heating module can also be configured to heat the resin that has been injected into the internal damaged area of ​​a component made of composite material.

[0040] The vacuum shroud preferably includes a first sealing connection that is configured as a joint between the sealing housing and the surface of an element made of composite material.

[0041] Furthermore, the resin reservoir preferably includes a second sealing connection configured to seal the junction between the resin reservoir and the surface of an element made of composite material.

[0042] According to a second embodiment of the apparatus for repairing components made of composite materials, the housing of the vacuum chamber is configured to create two separate internal spaces within the housing, namely:

[0043] o A first internal space, the first internal space being configured as a resin reservoir and configured to contain resin to be infused into the internal damaged area; and

[0044] o Second internal space, which is configured as a receiving part and connected to a vacuum guide. Attached Figure Description

[0045] As a means of better understanding at least one embodiment of the present invention, the following set of figures are presented schematically and in a non-limiting manner.

[0046] Figure 1 A schematic diagram of a conventional miter joint repair of a component made of composite material is shown.

[0047] Figure 2 A schematic diagram of a component made of composite material with an internal damaged area is shown.

[0048] Figure 3 This illustrates a component with several non-penetrating holes extending from both sides of a component made of composite material down to the internal damaged area. Figure 2 A schematic diagram of a component made of composite materials.

[0049] Figure 4 It shows Figure 4 A schematic diagram of a component made of composite material, wherein internal damaged areas and non-through holes have been filled with resin.

[0050] Figure 5 A schematic diagram of an apparatus for repairing components made of composite materials according to a first embodiment of the present invention is shown.

[0051] Figure 6 A schematic diagram of an apparatus for repairing components made of composite materials according to a second embodiment of the present invention is shown. Detailed Implementation

[0052] As already described, the present invention relates to a method and apparatus 400 for repairing a component 100 made of composite materials.

[0053] Figure 1 A schematic diagram of a component 100 made of composite material repaired according to conventional methods is shown, wherein both the damaged or cracked surface of the component 100 to be repaired and the contact surface 501 of the repair layer 500 have been machined or beveled (e.g., using grinding or milling processes), and the repair layer 500 has been cut to precise dimensions to allow the repair layer 500 to be attached to the component 100 to be repaired and to achieve a defined overlap length of the contact surface 501 with the component 100 to be repaired along the stepped or beveled contact surface 501.

[0054] Figures 2 to 4 These respectively represent the successive stages in the repair method of the present invention.

[0055] like Figure 2 As illustrated, a conflicting situation occurs when internal damage or cracks appear in the element 100 made of composite material. Such damage or cracks involve the creation of at least one internal cavity formed by layered materials within the element 100 made of composite material.

[0056] The method includes: after detecting an internal damage area 101 or internal crack in a component or element 100 made of composite material (e.g., by means of an ultrasonic inspection method), drilling a plurality of non-penetrating holes 200 from at least one of the side 102 or the face of the component 100 made of composite material, each of the non-penetrating holes 200 extending from one of the side 102 or the face of the component 100 made of composite material to the internal damage area 101 (or internal crack area) within the component 100 made of composite material.

[0057] Figure 3 A plurality of non-through holes 200 are shown drilled from each of the sides 102 or faces of the element 100 made of composite material.

[0058] As already described, the internal damage region 101 typically includes at least one internal cavity in which the structure of the composite material has been delaminated, thereby creating a region of bond failure between the layers.

[0059] The holes drilled in the composite material component 100 to be repaired are non-through holes 200 with reduced diameter (typically 2 mm) so that the integrity and structure of the composite material component 100 are not seriously affected.

[0060] The method includes injecting resin 300 through at least one first non-through hole 200a and applying a vacuum from at least one second non-through hole 200b.

[0061] By means of a vacuum applied from at least one second non-through hole 200b, air is extracted from the internal damaged region 101, and resin 300 flows from at least one first non-through hole 200a to fill the internal damaged region 101 of the element 100 made of composite material until at least one second non-through hole 200b is filled.

[0062] The vacuum is applied in a pulsed mode, in which it is applied at a given frequency and at different pressure values ​​following the given frequency. For example, 0.8 mbar, 0.6 mbar, 0.4 mbar, 0.2 mbar, and then back to a new cycle of 0.8 mbar, 0.6 mbar, etc. Ideally, the vacuum pulse is activated once the resin 300 begins to flow on the outlet side of the composite laminate.

[0063] Vacuum pulses are designed to help resin 300 flow and remove cavitation that may lead to pore development by applying vacuum in a cyclic phase.

[0064] When resin 300 is infused, vibration is applied to the element 100 made of composite material to promote the movement of bubbles within the delamination region, allowing gas to escape from the internal damaged region 101. The vibration is preferably applied at a frequency between 20 Hz and 1000 Hz.

[0065] Figure 4 The internal damaged area 101 and the non-through hole 200 filled with resin 300 are shown in the element 100 made of composite material.

[0066] The resin 300 is preferably heated before being poured into the internal damaged area 101 in order to achieve a minimum viscosity value that is easy to pour into the internal damaged area 101.

[0067] In addition, during the initial 15 to 20 minutes after the start of infusion (vacuum activation), the heating lamp or heating system maintains the temperature of the resin 300 at the lowest viscosity value.

[0068] In addition, after the pouring phase (15 to 20 minutes or the resin reservoir 402 is emptied), the heating system raises the temperature to begin the curing cycle according to the required resin 300 specification.

[0069] Once the resin 300 is injected into the internal damaged area 101 of the component 100 made of composite material and once the resin 300 is cured, the structural properties (resistance and load-bearing capacity) of the component 100 made of composite material are fully restored.

[0070] As already mentioned, the present invention also relates to an apparatus 400 for repairing an element 100 made of composite material.

[0071] Figure 5 An apparatus 400 for repairing a component 100 made of composite material according to a first embodiment of the present invention is schematically depicted.

[0072] The device 400 includes an outlet mask 401 (or vacuum hood), a resin reservoir 402, and a heating module 403.

[0073] The mask 401 is configured to be arranged in the layered region of the element 100 made of composite material, and more specifically in the outlet side of the element 100 made of composite material.

[0074] The resin reservoir 402 is configured to be arranged in the layered region of the element 100 made of composite material, and more specifically at the inlet side of the element 100 made of composite material.

[0075] The heating module 403 is arranged to correspond to the resin reservoir 402.

[0076] As in Figure 5 The heating module 403, which is schematically depicted in the diagram, can be a heating lamp.

[0077] The mask 401 includes a housing 404 configured to create a receiving portion 405 between an element 100 made of composite material and a housing 404.

[0078] The mask 401 includes an outlet guide 406 configured to receive resin flowing out from the second non-through hole 200b and through the receiving portion 405. In the event of a vacuum, the outlet guide 406 (or vacuum guide) is also configured to apply and / or provide a vacuum to the interior of the receiving portion 405.

[0079] The vacuum chamber 401 also includes a vacuum impact module 407, which is configured to establish a pulse mode for controlling the application of vacuum inside the opposing receiving portion 405.

[0080] The vacuum chamber 401 also includes a vibration module 408 configured to generate vibrations (preferably at a frequency between 20 Hz and 1000 Hz) and transmit the vibrations to the element 100 made of a composite material. For example, the vibration module 408 may include an electrically displaced mass block (or multiple electrically displaced mass blocks) configured to generate alternating in-plane vibrations.

[0081] The vacuum shroud 401 also includes a first sealing connection 409, which is configured as a joint between the sealing housing 404 and the surface of the outlet side of the element 100 made of composite material.

[0082] The resin reservoir 402 also includes a second sealing connection 410, which is configured to seal the joint between the resin reservoir 402 and the inlet side surface of the element 100 made of composite material.

[0083] The resin reservoir 402 is configured to be filled with resin 300 to be injected into the internal damaged area 101 of the component 100 made of composite material.

[0084] The heating module 403 is configured to heat the resin 300 in the resin reservoir 402 and maintain the resin 300 at a predetermined temperature value that ensures the minimum viscosity of the resin 300 to be injected into the internal damaged area 101 of the component 100 made of composite material.

[0085] The heating module 403 is also configured to apply heat to the resin 300 that has been infused into the internal damaged area 101 of the component 100 made of composite material, in order to ensure that the infused resin 300 is cured inside the component 100 made of composite material.

[0086] Figure 6 An apparatus for repairing components made of composite materials according to a second embodiment of the invention is schematically depicted.

[0087] According to the second embodiment, the device 400 is intended to be used when the internal damaged area 101 of the element 100 made of composite material can only be accessed from one side of the element 100 made of composite material.

[0088] Therefore, in this case, the first non-through hole 200a and the second non-through hole 200b extend from the same side of the element made of composite material to the internal damage region 101.

[0089] like Figure 6 As shown, the housing 404 of the vacuum chamber 401 creates two separate internal spaces within the housing 404, namely:

[0090] - A first internal space configured to serve as a resin reservoir 402 and configured to accommodate resin 300 to be infused into the internal damaged area 101;

[0091] - A second internal space, which is configured as a receiving part 405 and connected to a vacuum guide 406.

[0092] The first internal space, configured as a resin reservoir 402, can be connected to a resin supply device.

[0093] In addition, the heating module 403 is arranged to correspond to the resin reservoir 402 and / or the resin supply device.

Claims

1. A method for repairing an element (100) made of a composite material, the method comprising, after detecting an internal damaged region (101) within the element (100) made of the composite material, infusing resin (300) into the internal damaged region (101) of the element (100) made of the composite material, wherein, The method includes: Drill at least one first non-penetrating hole (200a) and at least one second non-penetrating hole (200b) into the component (100) made of the composite material, each of the at least one first non-penetrating hole (200a) and the at least one second non-penetrating hole (200b) extending from one face of the component (100) made of the composite material at least to the internal damaged area (101); and The resin (300) is injected from the at least one first non-through hole (200a) until the resin (300) fills at least a portion of the internal damaged area (101) of the element (100) made of composite material; The method is characterized in that it includes applying vibration to the element (100) made of composite material at a given frequency.

2. The method for repairing a component (100) made of composite material according to claim 1, characterized in that, Applying vibration to the component (100) made of composite material includes directly impacting or shaking the component (100) made of composite material using mechanical devices.

3. The method for repairing a component (100) made of composite material according to claim 1 or 2, characterized in that, Applying vibration to the element (100) made of composite material includes applying a varying vacuum at the at least one second non-through hole (200b).

4. The method for repairing an element (100) made of composite material according to any of the preceding claims, characterized in that, The vibration is applied at a frequency value between 0.5 and 1.5 times that of the normal frequency mode corresponding to the element (100) made of composite material.

5. The method for repairing an element (100) made of composite material according to any of the preceding claims, characterized in that, The method includes heating the resin (300) before infusing the resin (300) into the internal damaged area (101) of the element (100) made of the composite material.

6. The method for repairing an element (100) made of composite material according to any one of claims 1 to 5, characterized in that, The at least one first non-through hole (200a) extends from the first face of the element (100) made of composite material at least to the internal damage region (101), and the at least one second non-through hole (200b) extends from the second face of the element (100) made of composite material at least to the internal damage region (101).

7. The method for repairing an element (100) made of composite material according to any of the preceding claims, characterized in that, Each first non-through hole (200a) and each second non-through hole (200b) are distributed such that the projection of each first non-through hole (200a) on the second surface of the element (100) made of composite material does not coincide with the projection of any second non-through hole (200b) on the second surface of the element (100) made of composite material, and the projection of each second non-through hole (200b) on the first surface of the element (100) made of composite material does not coincide with the projection of any first non-through hole (200a) on the first surface of the element (100) made of composite material.

8. An apparatus (400) for repairing a component (100) made of a composite material, the component (100) having an internal damaged region (101) accessible from the outside of the component (100) through at least one first non-penetrating hole (200a) and at least one second non-penetrating hole (200b), wherein, The device (400) is characterized in that it comprises: A resin reservoir (402) configured to contain resin to be injected into the internal damaged region (101) of the element (100) made of composite material through the at least one first non-through hole (200a); An outlet mask (401) is connected to an outlet guide (406). The outlet mask (401) includes a housing (404) configured to define a receiving portion (405) between the at least one second non-penetrating hole (200b) and the outlet guide (406). The receiving portion (405) is isolated from the resin reservoir (402), wherein the receiving portion (405) is configured to receive resin flowing out from the at least one second non-penetrating hole (200b). Device for generating vibrations to be transmitted to the element (100) made of composite material.

9. The apparatus (400) for repairing a component (100) made of composite material according to claim 8, characterized in that, The device for generating vibrations to be transmitted to the element (100) made of composite material includes a vibration module (408) configured to generate mechanical vibrations to be transmitted to the element (100) made of composite material.

10. The apparatus (400) for repairing a component (100) made of composite material according to claim 8 or 9, characterized in that, The device for generating vibrations to be transmitted to the element (100) made of composite material includes a vacuum pulse module (407) configured to establish a pulse pattern for controlling the application of a vacuum to the interior of the receiving portion (405).

11. The apparatus (400) for repairing a component (100) made of composite material according to any one of claims 8 to 10, characterized in that, The device (400) includes a heating module (403) configured to heat the resin contained in the resin reservoir (402).

12. The apparatus (400) for repairing a component (100) made of composite material according to claim 11, characterized in that, The heating module (403) is also configured to heat the resin (300) injected into the internal damaged area (101) of the element (100) made of composite material.

13. The apparatus (400) for repairing a component (100) made of composite material according to any one of claims 8 to 12, characterized in that, The vacuum shroud (401) includes a first sealing connection (409) configured to seal the joint between the housing (404) and the surface of the element (100) made of composite material.

14. The apparatus (400) for repairing a component (100) made of composite material according to any one of claims 8 to 13, characterized in that, The resin reservoir (402) includes a second sealing connection (409) configured to seal the joint between the resin reservoir (402) and the surface of the element (100) made of composite material.

15. The apparatus (400) for repairing a component (100) made of composite material according to any one of claims 8 to 14, characterized in that, The housing (404) of the vacuum chamber (401) is configured to create two separate internal spaces within the housing (404): A first internal space, the first internal space being configured as the resin reservoir (402), and the first internal space being configured to contain the resin (300) to be infused into the internal damaged area (101); The second internal space is configured as the receiving part (405) and is connected to the vacuum guide (406).

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