Composite material repairing method and repairing structure

Abstract

The invention provides a composite material repairing method and a repairing structure. The composite material repairing method comprises the steps that a damaged area on a composite material is polished to remove damaged original fiber layers to form a repairing area, and the sections of the multiple original fiber layers exposed out of the edge of the repairing area form a lap joint area; a first fiber repairing layer is laid in the repairing area and the lap joint area, so that the two ends of the first fiber repairing layer obliquely and upwards extend to the topmost original fiber layer of the lap joint area correspondingly and are in lap joint with the topmost original fiber layer; sequentially laying a plurality of fiber repairing layers on the first fiber repairing layer until the number of the laid fiber repairing layers is the same as that of the polished original fiber layers; the topmost fiber repairing layer and the topmost original fiber layer are coated with adhesive surface layers, protective layers are laid on the adhesive surface layers, and the protective layers cover the fiber repairing layers and the original fiber layers; and putting the repaired composite material into an autoclave for curing. The problems that in the prior art, a repairing method is complex in process and low in efficiency are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of composite materials, and in particular to a repair method and a repair structure of a composite material. Background Art

[0002] Composite materials are widely used in modern aircraft design due to their high strength and lightweight properties. However, damage is inevitable during long-term use. Because composite materials are primarily composed of fibers and a resin matrix, which is significantly different from metal materials, repairing composite materials is a significant challenge.

[0003] The current method for repairing damaged composite materials is to remove the damaged fiber layer and then lay new fiber layers layer by layer in the place where the damaged fiber layer was removed, and each fiber layer is overlapped with the fiber layer of the corresponding layer on the composite material body. This repair method is extremely complicated and tedious because each fiber layer needs to be overlapped with the fiber structure layer of the corresponding layer on the composite material body. The repair efficiency is low, and the overlapping surface on the lower layer will be covered by the overlapping surface on the upper layer, which makes the installation and inspection of each overlapping surface, i.e. the repair area, more difficult. Summary of the Invention

[0004] In view of the above-mentioned shortcomings of the prior art, the object of the present invention is to provide a composite material repair method and repair structure, which are used to solve the problems of complex process and low efficiency of the repair method in the prior art.

[0005] To achieve the above-mentioned and other related objectives, the first aspect of the present invention provides a composite material repair method, comprising the following steps:

[0006] S1. Grinding the damaged area on the composite material to remove the damaged original fiber layer, thereby forming a repair area, wherein the cross sections of the multiple original fiber layers exposed at the edge of the repair area form an overlapping area;

[0007] S2. Laying a first fiber repair layer coated with resin in the repair area and the overlap area, wherein laying the first fiber repair layer specifically comprises first applying a first adhesive surface layer to the repair area and the overlap area, and then laying the first fiber repair layer on the first adhesive surface layer, with both ends of the first fiber repair layer extending obliquely upward to the topmost original fiber layer in the overlap area and overlapping the topmost original fiber layer;

[0008] S3, sequentially laying multiple fiber repair layers brushed with resin on the first fiber repair layer until the number of laid fiber repair layers is the same as the number of original fiber layers polished away, wherein the laying method of each fiber repair layer is the same as the method of laying the first fiber repair layer in step S2;

[0009] S4. Applying a rubber surface layer on the topmost fiber repair layer and the topmost original fiber layer, and laying a protective layer on the rubber surface layer, wherein the protective layer covers the fiber repair layer and the original fiber layer;

[0010] S5. Place the composite material repaired in step 4 into an autoclave for curing, so that the laid multi-layer fiber repair layer and protective layer are cured.

[0011] Furthermore, in step 2, before laying the first fiber repair layer on the first adhesive surface layer, the method further includes arranging a first strain sensor on the first adhesive surface layer.

[0012] Furthermore, in step S4, before laying the protective layer on the adhesive surface layer, a second strain sensor is provided on the adhesive surface layer, and the second strain sensor is located between the topmost fiber repair layer and the protective layer.

[0013] Furthermore, the adhesive surface layer is made of epoxy resin.

[0014] Furthermore, the material of the protective layer is the same as that of the fiber repair layer.

[0015] As described above, the composite material repair method of the present invention has the following beneficial effects: the composite material repair method of the present invention only requires overlapping the bottom fiber repair layer with the top original fiber layer on the composite material body, and then sequentially gluing fiber repair layers onto the bottom fiber repair layer. Compared with the prior art, which requires each newly laid fiber layer to overlap with the original fiber layer of the corresponding layer on the composite material body, the repair process and the difficulty of the repair process are greatly simplified, thereby greatly improving the efficiency of composite material repair. At the same time, the provision of the first strain sensor and the second strain sensor enables real-time safety performance monitoring of the repair area, greatly improving the reliability of the composite material during use. In particular, for the repair of composite materials used in aircraft, the composite material repair method of the present invention has important significance and value.

[0016] The second aspect of the present invention provides a composite material repair structure made by the above-mentioned composite material repair method, which includes a composite material body, a repair area is provided on the composite material body, and multiple fiber repair layers are provided on the repair area. A first strain sensor is provided between the fiber repair layer located at the bottom layer and the composite material body.

[0017] Furthermore, a protective layer is provided on the topmost fiber repair layer, and one end of the protective layer extends to the composite material body. A second strain sensor is provided between the protective layer and the topmost fiber repair layer.

[0018] The beneficial effects of the composite material repair structure of the present invention are the same as those of the composite material repair method described above, and therefore will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Shown is a process schematic diagram of the repair method for the composite material provided by the present invention.

[0020] Figure 2 Shown is a schematic diagram of the repair structure of the composite material provided by the present invention.

[0021] Description of Reference Numerals

[0022] 10 Composite material body

[0023] 11 Original fiber layer

[0024] 20 fiber repair layer

[0025] 21 First strain sensor

[0026] 22 Second strain sensor

[0027] 23 protective layer DETAILED DESCRIPTION

[0028] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different perspectives and applications without departing from the spirit of the present invention.

[0029] In the description of the present invention, it should be noted that, unless otherwise specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed or detachable connections, or integral connections; mechanical or electrical connections; direct connections or connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0030] In the description of the present invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," etc. used in the present invention to indicate orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings and are intended only to facilitate the description of the present invention and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the present invention. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0031] See also Figure 1 and Figure 2 It should be noted that the diagrams provided in this embodiment are merely schematic illustrations of the basic concept of the present invention. Therefore, the diagrams only show components relevant to the present invention and are not drawn according to the number, shape, and size of components in actual implementation. In actual implementation, the type, quantity, and proportion of each component may be arbitrarily changed, and the component layout may also be more complex.

[0032] The present invention provides a composite material repair method, wherein the composite material includes an original fiber layer and a resin matrix, and the repair method specifically comprises the following steps:

[0033] S1. Grinding the damaged area on the composite material to remove the damaged original fiber layer, thereby forming a repair area, wherein the cross sections of the multiple original fiber layers exposed at the edge of the repair area form an overlapping area;

[0034] Specifically, before grinding the damaged area on the composite material, the specific location and area of ​​the damage can be confirmed first, and then the area to be grinded can be marked with a marker; when grinding, a micro grinder can be used to grind the marked damaged area, that is, the damaged original fiber layer layer by layer.

[0035] For the convenience of description and expression, it is advisable to define the fiber layer of the composite material itself as the original fiber layer 11. It can be understood that after polishing the damaged original fiber layer 11 on the composite material, a low-lying repair area will be formed. The cross-section of the multiple layers of original fiber layers exposed at the edge of the low-lying repair area is the overlapping area, and the overlapping area has a certain inclination angle, that is, a bevel angle.

[0036] Specifically, in order to ensure the repair effect, when grinding the damaged area on the composite material, the bevel angle of the edge of the repair area formed by grinding needs to be determined according to the strength of the composite material. Specifically, the cross-section of the multiple original fiber layers, that is, the overlapping area, is defined to form the hypotenuse of a right triangle. The thickness of the original fiber layer that has been ground off is a vertical right-angled side (that is, the thickness of the overlapping area in the vertical direction), and the projection of the overlapping area in the horizontal direction is a horizontal right-angled side (that is, the width of the overlapping area). When the composite material is medium-strength fiber, the ratio of the thickness of the overlapping area in the vertical direction to the width of the overlapping area is 1:30, which is the best. When the composite material is high-strength fiber, the ratio of the thickness of the overlapping area in the vertical direction to the width of the overlapping area is 1:40, which is the best.

[0037] Specifically, in this embodiment, the original fiber layer of the composite material is carbon fiber or glass fiber, and the resin matrix is ​​epoxy resin.

[0038] S2. Laying a first fiber repair layer coated with resin in the repair area and the overlap area, wherein laying the first fiber repair layer specifically comprises first applying a first adhesive surface layer to the repair area and the overlap area, and then laying the first fiber repair layer on the first adhesive surface layer, with both ends of the first fiber repair layer extending obliquely upward to the topmost original fiber layer in the overlap area and overlapping the topmost original fiber layer;

[0039] Specific as Figure 1 As shown (only one end of the overlap diagram is shown in the figure), it can be understood that in this step S2, when the first fiber repair layer, that is, the bottom fiber repair layer 20, is laid in the repair area, both ends of the bottom fiber repair layer 20 are inclined to extend upward to the top original fiber layer 11 of the overlap area, and overlap on the top original fiber layer 11, that is, the end of the bottom fiber repair layer 20 is connected to the cross-section of the multiple original fiber layers exposed at the edge of the repair area, and then the end is overlapped on the top original fiber layer.

[0040] Specifically, in this embodiment, the first adhesive surface layer is made of epoxy resin, and the fiber repair layer 20 is made of the same material as the original fiber layer 11 of the composite material. Specifically, in step S2, the first fiber repair layer coated with resin is understood to be a wet fiber repair layer coated with resin, specifically epoxy resin.

[0041] Furthermore, in order to conveniently and in real time perform safety inspection on the performance of the repaired area during use, Figure 2As shown, in step S2, before laying the first fiber repair layer on the first adhesive surface layer, a first strain sensor 21 is also provided on the first adhesive surface layer, that is, between the first fiber repair layer (i.e., the bottommost fiber repair layer 20) and the original fiber layer 11. In this way, during use of the repaired composite material, the first strain sensor 21 can detect in real time the stress changes of the fiber repair layer in the repaired area during stress application, and transmit this stress change information to an external monitoring system, thereby performing a mechanical property analysis on the repaired area to determine whether the fiber repair layer in the repaired area has failed. If it is determined that the fiber repair layer in the repaired area has failed, the external monitoring system will issue an alarm signal, thereby achieving real-time safety monitoring of the repaired area.

[0042] S3, sequentially laying multiple fiber repair layers brushed with resin on the first fiber repair layer until the number of laid fiber repair layers is the same as the number of original fiber layers polished away, wherein the laying method of each fiber repair layer is the same as the method of laying the first fiber repair layer in step S2;

[0043] S4. Applying a rubber surface layer on the topmost fiber repair layer and the topmost original fiber layer, and laying a protective layer on the rubber surface layer, wherein the protective layer covers the fiber repair layer and the original fiber layer.

[0044] Specifically, in this embodiment, the material of the applied adhesive surface layer is epoxy resin.

[0045] Furthermore, in order to be able to perform safety detection on the performance of the protective layer 23 in real time during use, Figure 2 As shown, in this step S4, before laying the protective layer 23 on the adhesive surface layer, a second strain sensor 22 is also included on the adhesive surface layer, and the second strain sensor 22 is set between the topmost fiber repair layer 20 and the protective layer 23. In this way, during use, the stress change of the protective layer during the stress process can be detected in real time by the second strain sensor 22, and the stress change information is transmitted to the external monitoring system, and then the mechanical performance analysis of the protective layer is performed to determine whether the protective layer has failed. When it is determined that the protective layer has failed, the external monitoring system will issue an alarm signal, realizing real-time safety monitoring of the protective layer. Of course, in actual use, the stress change information detected by the first strain sensor 21 and the second strain sensor 22 can also be used for collaborative analysis to determine the safety performance of the repair area, so that the safety performance detection of the repair area is more accurate.

[0046] Specifically, in this embodiment, the material of the protective layer and the material of the fiber repair layer can be the same or different.

[0047] S5. Place the composite material repaired in step 4 into an autoclave for curing, so that the laid multi-layer fiber repair layer and protective layer are cured.

[0048] As can be seen from the above, the composite material repair method of the present invention only requires overlapping the bottom fiber repair layer with the top original fiber layer on the composite material body, and then sequentially gluing fiber repair layers onto the bottom fiber repair layer. Compared with the prior art, which requires each newly laid fiber layer to overlap with the original fiber layer of the corresponding layer on the composite material body, this greatly simplifies the repair process and the difficulty of the repair process, thereby significantly improving the efficiency of composite material repair. At the same time, the provision of the first strain sensor and the second strain sensor enables real-time safety performance monitoring of the repair area, greatly improving the reliability of the composite material during use. The composite material repair method of the present invention is of great significance and value, especially for repairing composite materials used in aircraft.

[0049] Another aspect of the present invention provides a composite material repair structure made by the above composite material repair method, such as Figure 2 As shown, the composite repair structure includes a composite body 10 , a repair area is provided on the composite body 10 , a plurality of fiber repair layers 20 are provided on the repair area, and a first strain sensor 21 is provided between the bottom fiber repair layer 20 and the composite body 10 .

[0050] In order to further improve the service life and strength of the composite material repair structure, preferably, a protective layer 23 is provided on the topmost fiber repair layer 20, and one end of the protective layer 23 extends to the composite material body 10, and a second strain sensor 22 is provided between the protective layer 23 and the topmost fiber repair layer 20.

[0051] The beneficial effects of the composite material repair structure of the present invention are the same as those of the composite material repair method described above, and therefore will not be described in detail here.

[0052] In summary, the composite material repair method of the present invention can significantly improve the efficiency of composite material repair and enable real-time safety performance monitoring of the repaired area. Therefore, the present invention effectively overcomes the various shortcomings of the prior art and has high industrial application value.

[0053] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A composite material repair method, wherein the composite material comprises an original fiber layer and a resin matrix, characterized in that: The steps include: S1. Grinding the damaged area on the composite material to remove the damaged original fiber layer, thereby forming a repair area, wherein the cross sections of the multiple original fiber layers exposed at the edge of the repair area form an overlap area; S2, laying a first fiber repair layer brushed with resin in the repair area and the overlap area, wherein laying the first fiber repair layer specifically comprises first brushing a first adhesive surface layer in the repair area and the overlap area, and then laying the first fiber repair layer on the first adhesive surface layer, and making the two ends of the first fiber repair layer extend obliquely upward to the original fiber layer at the top of the overlap area, and overlap on the original fiber layer at the top; S3, sequentially laying multiple fiber repair layers brushed with resin on the first fiber repair layer until the number of laid fiber repair layers is the same as the number of original fiber layers polished off, wherein the laying method of each fiber repair layer is the same as the method of laying the first fiber repair layer in step S2; S4, applying a rubber surface layer on the topmost fiber repair layer and the topmost original fiber layer, and laying a protective layer on the rubber surface layer, wherein the protective layer covers the fiber repair layer and the original fiber layer; S5. Put the repaired composite material in step 4 into an autoclave for curing, so that the laid multi-layer fiber repair layer and protective layer are cured.

2. A composite material repair method according to claim 1, characterized in that: In step 2, before laying the first fiber repair layer on the first adhesive surface layer, the method further includes providing a first strain sensor on the first adhesive surface layer.

3. A composite material repair method according to claim 1, characterized in that: In step S4, before laying the protective layer on the adhesive surface layer, a second strain sensor is provided on the adhesive surface layer, and the second strain sensor is located between the topmost fiber repair layer and the protective layer.

4. A composite material repair method according to claim 1, characterized in that: The material of the adhesive surface layer is epoxy resin.

5. A composite material repair method according to claim 1, characterized in that: The material of the protective layer is the same as that of the fiber repair layer.

6. A composite material repair structure made by the composite material repair method according to any one of claims 1 to 5, characterized in that: The composite material repair structure comprises a composite material body, a repair area is provided on the composite material body, a plurality of fiber repair layers are provided on the repair area, and a first strain sensor is provided between the fiber repair layer at the bottom and the composite material body.

7. A composite material repair structure according to claim 6, characterized in that: A protective layer is provided on the fiber repair layer at the top layer, and one end of the protective layer extends to the composite material body. A second strain sensor is provided between the protective layer and the fiber repair layer at the top layer.

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