Repair method for interface defects of resin-based multilayer composite material

Abstract

The invention belongs to the technical field of product repairing and life prolonging, and discloses a method for repairing interface defects of a resin-based multilayer composite material, and the method comprises the following steps: determining a damaged area of the interface defects and the depth of the interface defects; according to the geometrical shape of the damaged area of the interface defect and the depth of the interface defect, the positions and depths of a glue injection hole and a vent hole are determined; forming a glue injection hole and a vent hole in the damaged area of the interface defect, and enabling the glue injection hole and the vent hole to be communicated with the interface defect; compressed gas is introduced into the glue injection hole, and whether airflow exists at the vent hole or not is detected; and after communication is confirmed, a repairing agent is adopted for glue injection, the repairing agent is injected into the interface defect through the glue injection hole and discharged through the vent hole, and then pre-curing is conducted according to the curing requirement of the repairing agent. According to the method, the problem that the composite material and the thin-layer composite material with damping requirements are difficult to repair due to the fact that the cavities are not matched with a common repair method due to layering in the composite material and the thin-layer composite material is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of product repair and life extension, and specifically relates to a method for repairing interface defects of a resin-based multilayer composite material. Background Art

[0002] Advanced resins and their composite materials play an important role in the development of national defense, military and civilian fields due to their light weight, good mechanical properties, flexible structural design, adjustable performance, wide sources and low cost. They are currently widely used in various types of aerospace, ships, automobiles, etc. Reducing the weight of various devices, improving the mobility of devices, and reducing operating costs are the most direct purposes of using resin-based composite materials.

[0003] After years of development, composite materials have entered a mature application period. The experience in design, manufacturing and use has become increasingly rich. The scope of application has developed from non-load-bearing components to secondary load-bearing and main load-bearing components, achieving a significant effect of reducing the weight of equipment by 20%-30%, greatly improving the technical level, reliability, durability and maintainability of equipment. However, composite materials also have obvious disadvantages, namely, poor mechanical properties between layers. Whether it is defects in the raw materials themselves, or damage caused by the manufacturing process and external loads, such as delamination and debonding, the main load-bearing structure of the equipment will be damaged and the surface aerodynamic performance will decrease, thereby reducing the service life of the equipment and increasing safety risks.

[0004] At present, the commonly used repair methods include mechanical connection repair and bonding repair: Mechanical connection repair is to fix an external patch with bolts or rivets on the outside of the damaged structure, so that the damaged load transfer path of the damaged structure can be restored. Most of the connection methods use bolt connection, and rivet connection can also be used. Mechanical connection repair is to reinforce the defective part with fasteners, which can only achieve the effect of strengthening and inhibiting the development of defects, and cannot cause substantial repair of the damage; and because the composite material has brittle and anisotropic properties, stress concentration will occur at the edge of the bolt hole or rivet hole, resulting in poor fatigue resistance, so that mechanical connection repair cannot cause substantial repair of the damage. Bonding repair includes cut-and-fill method and patch repair; the cut-and-fill method removes the outside of the damaged area of ​​the composite material and then fills it. First of all, from the perspective of cost, the cut-and-fill method uses a large amount of repair agents, which leads to an increase in cost. Secondly, the repair speed of the cut-and-fill method is slow and cannot meet the so-called rapid repair standard. On the other hand, the cut-and-fill method causes great damage to the original structure of the composite material, and the damping performance of the composite material with damping requirements is greatly lost; patch repair is suitable for surface repair of composite materials, but not for internal damage.

[0005] It can be seen that although the prior art discloses mechanical connection repair and bonding repair for repairing interface defects, both methods are unable to achieve the repair of composite materials and thin-layer composite materials with damping requirements. The reason is that: after using mechanical connection repair and bonding repair to repair composite materials with damping requirements, the composite materials will not meet their damping performance; if mechanical connection repair is used to repair thin-layer composite materials, stress concentration will occur at the edges of bolt holes or rivet holes, causing great damage to the structure of the thin-layer composite materials. At the same time, due to the thin characteristics of thin-layer composite materials, they are not suitable for bonding repair using the cut-and-fill method.

[0006] Based on this, a completely new repair method is needed to achieve the repair of composite materials and thin-layer composite materials with damping requirements. Summary of the invention

[0007] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide a method for repairing interface defects of resin-based multilayer composite materials, so as to solve the problem that composite materials with damping requirements and thin-layer composite materials are difficult to repair due to the internal stratification and cavities that are not compatible with commonly used repair methods.

[0008] The present invention is achieved through the following technical solutions:

[0009] A method for repairing interface defects of a resin-based multilayer composite material comprises the following steps:

[0010] Determine the damage area of ​​the interface defect and the depth of the interface defect;

[0011] Determine the position and depth of the injection hole and the vent hole according to the geometric shape of the damaged area of ​​the interface defect and the depth of the interface defect;

[0012] A glue injection hole and a vent hole are respectively opened on the damaged area of ​​the interface defect, and both the glue injection hole and the vent hole are connected to the interface defect;

[0013] Inject compressed gas into the injection hole and check whether there is airflow at the vent hole to verify whether the injection hole and the vent hole are connected, and use compressed gas to blow away the dust generated during the drilling process;

[0014] After confirming the connection, use the repair agent to inject glue. Inject the repair agent into the interface defect through the injection hole and discharge it through the vent hole. Stop injecting glue after there is no dust in the repair agent discharged from the vent hole. Then pre-cure according to the curing requirements of the repair agent.

[0015] After pre-curing is completed, glue repair is carried out and the repair agent is cured. The pre-curing time is much shorter than the curing time. The purpose of pre-curing is to make the repair agent have a certain strength so that it can maintain a solid state and complete the repair.

[0016] Preferably, the resin-based multilayer composite material is first inspected visually and by tapping to locate the target area where the interface defect occurs, and then the target area is scanned by non-destructive testing to determine the position and depth of the interface defect.

[0017] Preferably, for interface defects with regular shapes or less than or equal to 2 corners, such as circles, ellipses, and long cracks, select the longest line segment in the plane diagram of the damaged area, take a point at each end of the circle along the diameter, and take a point at each end of the line segment and 2-3mm away from the edge of the interface defect to drill glue injection holes and vents.

[0018] Preferably, for irregularly shaped interface defects, when the number of horns is greater than 2, a glue injection hole is drilled at the tip of the horn and 2-3 mm away from the edge of the interface defect, and a vent hole is made at the geometric center of the interface defect.

[0019] Preferably, if the glue injection hole and the vent hole are not connected, select a point close to the edge of the interface defect and equidistant from the non-connected glue injection hole and vent hole to make the glue injection hole and the vent hole, repeat the purge, and if they still cannot be connected, use the same operation to select a different glue injection hole, and then perform new glue injection hole and vent hole drilling operations until the glue injection hole and the vent hole are connected.

[0020] Preferably, the diameters of the injection holes and the vent holes are both 2-3 mm.

[0021] Preferably, if it is difficult to inject the repair agent, a sealing rubber pad is installed on the vent hole, and vacuum is drawn at the position of the sealing rubber pad to assist the injection.

[0022] Preferably, a vibration device is used during the glue injection process to maintain high-frequency vibration of the resin-based multilayer composite material to promote the flow of the repair agent.

[0023] Preferably, the injection speed of the injection process is 0.2-0.6 mL / min. If the injection speed is too fast, it will easily lead to incomplete filling of the adhesive, and if it is too slow, the efficiency will be low because the operation time of some adhesives is short. If it is too slow, the utilization rate of the adhesive will be reduced.

[0024] Preferably, the depths of the glue injection holes and the vent holes are both greater than the depth of the interface defect, and are both less than the height of the resin-based multilayer composite material.

[0025] Preferably, after curing is completed, residual glue is cleaned, and non-destructive testing is performed on the repaired resin-based multi-layer composite material. The repair is completed after the test is qualified.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. The present invention adopts a punching and injection method to repair interface defects of resin-based multilayer composite materials, specifically: first observe and knock to check the approximate position of the interface defect, and then perform non-destructive testing to determine the damaged area of ​​the interface defect and the depth of the interface defect, judge the position, size and depth of the glue injection hole and the vent hole according to the damaged area and the depth of the interface defect, and then open the glue injection hole and the vent hole on the resin-based multilayer composite material, and then use compressed gas to detect the connectivity of the glue injection hole and the vent hole to ensure that the glue injection hole, the vent hole and the interface defect are connected. While confirming the connectivity, the compressed gas can also be used to blow away the dust generated during the drilling process; after determining that the glue injection hole and the vent hole are connected to the interface defect, the prepared repair agent is injected into the damaged area and pre-cured. Since the repair agent will shrink by about 2% in volume after curing, glue filling and curing are performed after pre-curing. After curing is completed, the resin-based multilayer composite material is subjected to non-destructive testing. After the test is qualified, the repair is completed.

[0028] 2. Compared with the existing cut-and-patch filling method, the cut-and-patch filling method requires the damaged area of ​​the resin-based multilayer composite material to be removed and then filled, so the damage to the resin-based multilayer composite material is large and the repair cost is high. The repair method of the present invention only opens a few holes, which on the one hand causes less damage to the resin-based multilayer composite material, and on the other hand, the repair cost is low. The reason is that the cost is mainly reflected in the amount of adhesive used. In addition to the adhesive required to fill the interface defects, the cut-and-patch filling method also requires filling the removed part and repairing the repaired resin-based multilayer composite material;

[0029] Compared with mechanical connection repair, the punching and injection method of the present invention causes less damage to the resin-based multilayer composite material, and effectively overcomes the problem of stress concentration at the edge of the bolt hole or rivet hole, and also avoids subsequent maintenance costs;

[0030] Therefore, compared with the existing mechanical connection repair and patching and filling methods, the present invention is more convenient and effective in repairing the enclosed space interface defects of resin-based multi-layer composite materials, has a fast repair speed, is easy to operate, causes little damage to the material structure, has a low repair cost, has guaranteed reliability, and has a significant repair effect.

[0031] 3. The interface defect repair method of the present invention realizes the repair of delamination and cavity inside the composite material and thin-layer composite material with damping requirements. The reason is that for the composite material with damping requirements, the cutting and filling method directly removes the outside of the damaged area and then fills it, which causes great damage to the original structure of the composite material with damping requirements, and then causes a large loss of damping performance of the composite material with damping requirements. The punching and injection method used in the present invention causes little damage to the composite material with damping requirements, so it has little effect on the damping performance;

[0032] For thin-layer composite materials, the punching and injection method of the present invention can perform depth control according to the thickness of the thin-layer composite materials, thereby achieving the purpose of repairing interface defects of the thin-layer composite materials. At the same time, the punching and injection method of the present invention causes little damage to the thin-layer composite materials, and also overcomes the problem of stress concentration at the edges of bolt holes or rivet holes. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a schematic diagram of a plane hole punching of a regular-shaped interface defect according to Example 2 of the present invention;

[0034] Figure 2 This is a schematic diagram of the plane drilling of irregularly shaped interface defects of the present invention;

[0035] Figure 3 It is a schematic diagram of re-drilling in the case where the injection hole and the vent hole in the irregularly shaped interface defect of the present invention are not connected;

[0036] Figure 4 It is a cross-sectional punching diagram of the interface defect of the resin-based multi-layer composite material of the present invention;

[0037] Figure 5 This is a schematic diagram of plane drilling of an irregularly shaped interface defect in Example 1 of the present invention.

[0038] Description of reference numerals:

[0039] 1. Interface defects; 2. Glue injection hole; 3. Vent hole; 4. Nozzle; 5. Syringe; 6. Sealing rubber pad; 7. Resin-based multilayer composite material. DETAILED DESCRIPTION

[0040] The specific embodiments of the present invention are described in detail below, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention. The experimental methods described in the embodiments of the present invention are conventional methods unless otherwise specified.

[0041] The interface defects treated by the present invention include debonding between layers, interface damage, pores, holes, looseness and matrix cracking. The present invention uses a punching and glue injection method to repair the interface defects of the repair object. The repair object includes resin-based multilayer composite materials and products made of resin-based multilayer composite materials, especially composite materials and thin-layer composite materials with damping requirements can also be repaired. The repair method of the present invention includes the following four parts: a. Determination of the damaged area and interface defect state of the product interface defect; b. Selection of repair agent according to the product; c. Pre-repair treatment of the product; d. Repair of the interface defects of the product; The method of the present invention not only overcomes the technical defects of the existing mechanical connection repair and patching and filling methods, but also realizes the repair of composite materials and thin-layer composite materials with damping requirements. It is a new method that can replace the existing mechanical connection repair and patching and filling methods.

[0042] The repair method of the present invention specifically comprises the following steps:

[0043] S1. Determination of the damaged area and state of the product interface defect 1:

[0044] First, the resin-based multilayer composite material 7 is observed by visual inspection for obvious defects, such as visible impact damage such as wrinkles, bridging, delamination, and thermal damage between layers;

[0045] Then check the product for delamination or debonding by tapping. Use a tapping hammer to gently tap along the surface of the product. A bright sound indicates a good structure, and a dull "thump" sound indicates a defect, such as delamination or debonding.

[0046] Finally, nondestructive testing methods such as ultrasonic (UT) are used for testing. According to the information carried by the signal, characteristics such as the damaged area, the size of the interface defect 1, and the direction of the interface defect 1 are obtained. The location of the damaged area and the depth of the interface defect 1 are determined by the above characteristics.

[0047] S2. Select the repair agent according to the product:

[0048] For bonding of larger areas and mass production, the adhesive needs to be prepared in advance, and the adhesive requires time to operate. At this time, a high-temperature epoxy adhesive is selected, and the selected high-temperature epoxy adhesive has a curing speed of at least 1 hour at room temperature; when the adherend needs to be light-transmitting, a light-curing adhesive is selected; when the adherend is a conductive connection in the electronics industry or replaces lead-tin soldering connections, an epoxy conductive adhesive is selected.

[0049] The theoretical dosage of the repair agent is based on Calculation: The theoretical dosage of the repair agent can be obtained by computer. Taking into account the actual need to expel some dust through the repair agent, the actual dosage is generally 130% of the theoretical dosage. According to the product, multiple repair agents are mixed according to the proportion in the instructions. If bubbles appear during the mixing process, ultrasonic and vacuum assisted defoaming are used. The total ultrasonic time should not be too long, generally 5-10 minutes, otherwise the viscosity of the repair agent will increase, making it difficult to inject.

[0050] S3. Process the product before repair:

[0051] The position and depth of the injection hole 2 and the vent hole 3 are determined according to the damage area and the depth of the interface defect 1. For interface defects 1 with regular shapes or less than or equal to 2 corners, such as round, oval, long cracks, Figure 1 As shown, select the longest line segment in the plane diagram of the damaged area, select a point at each of the two end points of the line segment and 2-3 mm away from the edge of the interface defect, and drill two holes with a diameter of 2-3 mm, which are the air vent and the injection hole respectively;

[0052] For the irregularly shaped interface defect 1, the number of horns is greater than 2. For example, a shape similar to a "four-leaf clover" Figure 2 As shown, a glue injection hole 2 is drilled at the tip of the horn and 2-3mm away from the edge of the interface defect, and a vent hole 3 is made at the geometric center of the interface defect. A handheld drill is used to make the glue injection hole 2 and the vent hole 3. The diameters of the glue injection hole 2 and the vent hole 3 are both 2-3mm. The depth of the drilling exceeds the location of the interface defect 1 to facilitate the filling of the repair agent.

[0053] S4. Repair the interface defect 1 of the product:

[0054] Inject compressed nitrogen into the injection hole 2 through the nozzle 4, detect whether there is airflow at the vent hole 3, verify whether the injection hole 2 is connected to the vent hole 3, and use compressed nitrogen to purge dust generated during the drilling process;

[0055] If the injection hole 2 is not connected to the vent hole 3, select a point close to the edge of the interface defect and equidistant from the non-connected injection hole 2 and vent hole 3 to make a new injection hole 1 and vent hole 3, and continue to inject compressed nitrogen into the injection hole 2 through the nozzle 4 to determine whether the injection hole 2 is connected to the vent hole 3;

[0056] After the injection hole 2 is connected to the vent hole 3, the prepared repair agent is slowly injected from the injection hole 2 to the interface defect 1 using a syringe 5, with an injection rate of 0.2-0.6 mL / min. If the injection is difficult, a sealing rubber pad 6 is installed at the vent hole 3, and a vacuum is drawn at the sealing rubber pad 6 to assist the injection. During the injection process, the damaged area of ​​the product is continuously vibrated until all the vent holes 3 overflow with the repair agent without bubbles and dust impurities; wipe off the residual glue, and select a suitable temperature for pre-curing according to the physical properties of the repair agent;

[0057] Since pre-curing may cause the repair agent to shrink, after pre-curing, the repair agent is used again to fill the shrinkage area in the injection hole 2 and the vent hole 3, and then fully cured. After the curing is completed, non-destructive testing is carried out. After passing the test, the repair is completed.

[0058] The technical solution of the present invention is further explained by using embodiments below, which are specifically as follows:

[0059] Example 1

[0060] As a specific implementation method, the following is applied to the repair of interface defect 1 in the enclosed space of a certain type of missile shell. After the repair, non-destructive testing was performed and it was confirmed that the interface defect 1 of the resin-based multi-layer composite material has been repaired completely.

[0061] A method for repairing interface defects of a resin-based multilayer composite material, this embodiment is for repairing irregular interface defects, comprising the following steps;

[0062] S1. Observe through visual inspection whether there is obvious visible impact damage on the composite sheet of a certain type of missile shell;

[0063] Then check the composite sheet for delamination or debonding by tapping it. Use a tapping hammer to gently tap along the surface of the composite sheet. A dull "bang" sound indicates a defect.

[0064] Finally, ultrasonic testing of the composite plate revealed that the composite plate had delamination damage at the junction between the internal epoxy film and the damping rubber, resulting in a cavity. The damaged area was located inside the composite plate and did not extend to the edge of the composite plate. The area of ​​the damaged area was 20 cm 2 The composite plate has a sandwich structure, and it is judged that the interface defect 1 is located on the two surfaces of the middle interlayer of the composite plate.

[0065] S2. Calculate the amount of repair agent to be used according to the size of the damaged area. The theoretical amount is based on Calculation shows that the theoretical dosage is the integrated volume, which is 1.27 mL. Taking into account the actual need to expel some dust through the repair agent, the actual dosage is 130% of the theoretical dosage, which is 1.7 mL. According to the composition of the composite board, a variety of repair agents are mixed in accordance with the proportions in the instructions. The repair agent is selected from J-133, and the mass ratio of component A: component B is 100:20. The repair agent is prepared. In order to avoid bubbles during the mixing process, ultrasonic and vacuum assisted defoaming are used, and the total ultrasonic time is 8 minutes.

[0066] S3, judging the position and depth of the injection hole 2 and the vent hole 3 according to the size of the damaged area and the depth of the interface defect 1, the damaged area is as follows Figure 5 For the irregularly shaped interface defect 1 shown in the figure, a glue injection hole 2 is drilled at the tip of the corner of the interface defect 1 and at a distance of 2 mm from the edge of the interface defect, and a vent hole 3 is made at the geometric center of the interface defect. The diameters of the glue injection hole 2 and the vent hole 3 are both 2 mm, and the drilling depth is greater than half of the thickness of the composite plate. At this time, both the upper bottom surface and the lower bottom surface can be guaranteed to be connected;

[0067] Compressed gas is injected from the injection hole 2 through the nozzle 4, and whether there is gas flowing out from the vent hole 3 is detected to determine whether the injection hole 2 and the vent hole 3 are connected. If it is found that they are connected, after determining that the gas is flowing, compressed gas is used to blow away the dust generated during the drilling process until the dust cannot be observed with the naked eye.

[0068] S4, using a syringe 5 to slowly inject the prepared repair agent into the interface defect 1 through the injection hole 2, with an injection rate of 0.4 mL / min. During the injection process, a vibration device is used to vibrate the damaged area of ​​the composite plate;

[0069] After the repair agent appears at the vent hole 3, continue the glue injection operation until the repair agent at the vent hole 3 is a repair agent without dust. The injection is completed, and the residual glue is wiped off. Then, pre-curing is performed according to the curing requirements of the repair agent, and pre-curing is performed at room temperature for 36 hours;

[0070] Since pre-curing may cause the repair agent to shrink, the repair agent will show obvious collapse in the injection hole 2 and the vent hole 3 after shrinkage. The repair agent is used again to fill the shrinkage area in the injection hole 2 and the vent hole 3, that is, glue filling is performed once after the pre-curing is completed, and then it is cured at 80°C for 2h. After the curing is completed, the residual glue is cleaned up.

[0071] S4. Perform nondestructive testing on the repaired composite plate. When the reflected wave obtained at the interface defect 1 is consistent with the reflected wave obtained in the non-delaminated area, the repair is effective.

[0072] Example 2

[0073] A method for repairing interface defects of a resin-based multilayer composite material, this embodiment is for repairing regular interface defects, comprising the following steps;

[0074] As a specific implementation method, the following is applied to the repair of interface defect 1 in the enclosed space of a certain type of missile shell. After the repair, non-destructive testing was performed and it was confirmed that the interface defect 1 of the resin-based multi-layer composite material has been repaired completely.

[0075] A method for repairing interface defects of a resin-based multilayer composite material comprises the following steps;

[0076] S1. Observe through visual inspection whether there is obvious visible impact damage on the composite sheet of a certain type of missile shell;

[0077] Then check the composite sheet for delamination or debonding by tapping it. Use a tapping hammer to gently tap along the surface of the composite sheet. A dull "bang" sound indicates a defect.

[0078] Finally, ultrasonic testing of the composite plate revealed that the composite plate had delamination damage at the junction of the internal epoxy film and the damping rubber, resulting in a cavity. The damaged area was located inside the composite plate and did not extend to the edge of the composite plate. The area of ​​the damaged area was 12 cm 2 The composite plate has a sandwich structure, and the interface defect 1 is located on the upper surface of the middle interlayer of the composite plate.

[0079] S2. Calculate the amount of repair agent to be used according to the size of the damaged area. The theoretical amount is based on Calculation shows that the theoretical dosage is the integrated volume, which is 0.83 mL. Taking into account the actual need to expel some dust through the repair agent, the actual dosage is 130% of the theoretical dosage, which is 1.1 mL. According to the composition of the composite board, a variety of repair agents are mixed in accordance with the proportions in the instructions. The repair agent is selected from DG-8, and the mass ratio of component A: component B is 12:1. The repair agent is prepared. In order to avoid bubbles during the mixing process, ultrasonic and vacuum assisted defoaming are used, and the total ultrasonic time is 10 minutes.

[0080] S3, judging the position and depth of the injection hole 2 and the vent hole 3 according to the size of the damaged area and the depth of the interface defect 1, the damaged area is as follows Figure 1 As shown in the figure, an interface defect 1 with a regular shape is selected. A longest line segment is selected in the plane diagram of the interface defect 1. A point is selected at each of the two end points of the line segment and 3 mm away from the edge of the interface defect 1. A glue injection hole 2 and a vent hole 3 are drilled. The diameters of the glue injection hole 2 and the vent hole 3 are both 2 mm, and the drilling depth is greater than half of the thickness of the composite plate.

[0081] Compressed gas is injected from the injection hole 2 through the nozzle 4, and whether there is gas flowing out from the vent hole 3 is detected to determine whether the injection hole 2 and the vent hole 3 are connected. If it is found that the gas is connected, the dust generated during the drilling process is continuously blown away with compressed gas until the dust cannot be observed with the naked eye.

[0082] S4, using a syringe 5 to slowly inject the prepared repair agent into the interface defect 1 through the injection hole 2, with an injection rate of 0.6 mL / min. During the injection process, a vibration device is used to vibrate the damaged area of ​​the composite plate;

[0083] After the repair agent appears at the vent hole 3, continue the glue injection operation until the repair agent at the vent hole 3 is a repair agent without dust. The injection is completed, and the residual glue is wiped off. Then, pre-curing is performed according to the curing requirements of the repair agent, and pre-curing is performed at room temperature for 1 hour;

[0084] Since pre-curing may cause the repair agent to shrink, the repair agent will show obvious collapse in the injection hole 2 and the vent hole 3 after shrinkage. The repair agent is used again to fill the shrinkage area in the injection hole 2 and the vent hole 3, that is, glue filling is performed once after the pre-curing is completed, and then it is cured at 64°C for 4 hours. After the curing is completed, the residual glue is cleaned up.

[0085] S4. Perform nondestructive testing on the repaired composite plate. When the reflected wave obtained at the interface defect 1 is consistent with the reflected wave obtained in the non-delaminated area, the repair is effective.

[0086] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, they are also intended to be included.

Claims

1. A method for repairing interface defects of a resin-based multilayer composite material, characterized in that: The steps include: Determine the damage area of ​​the interface defect and the depth of the interface defect; Determine the position and depth of the injection hole and the vent hole according to the geometric shape of the damaged area of ​​the interface defect and the depth of the interface defect; A glue injection hole and a vent hole are respectively opened on the damaged area of ​​the interface defect, and both the glue injection hole and the vent hole are connected to the interface defect; Inject compressed gas into the injection hole and check whether there is airflow at the vent hole to verify whether the injection hole and the vent hole are connected, and use compressed gas to blow away the dust generated during the drilling process; After confirming the connection, the repair agent is used for injection. The repair agent is injected into the interface defect through the injection hole and discharged through the vent hole. Then, pre-curing is performed according to the curing requirements of the repair agent. After the pre-curing is completed, a repair agent is used to fill the glue, and the repair agent is cured to complete the repair.

2. The method for repairing interface defects of a resin-based multilayer composite material according to claim 1, characterized in that: First, the resin-based multilayer composite material is inspected visually and by tapping to locate the target area and defect type where the interface defects occur. Then, the target area is scanned by nondestructive testing to determine the location and depth of the interface defects.

3. The method for repairing interface defects of a resin-based multilayer composite material according to claim 1, characterized in that: For interface defects with regular shapes or less than or equal to 2 corners, select the longest line segment in the plane diagram of the damaged area, select a point at each end of the line segment and 2-3mm away from the edge of the interface defect, and drill the glue injection hole and the vent hole.

4. The method for repairing interface defects of a resin-based multilayer composite material according to claim 1, characterized in that: For irregularly shaped interface defects, drill a glue injection hole at the tip of the corner and 2-3mm away from the edge of the interface defect, and make a vent hole at the geometric center of the interface defect.

5. The method for repairing interface defects of a resin-based multilayer composite material according to claim 1, characterized in that: If the injection hole and the vent hole are not connected, select a point close to the edge of the interface defect and equidistant from the non-connected injection hole and vent hole to make the injection hole and vent hole, and repeat the purge until the injection hole and the vent hole are connected.

6. The method for repairing interface defects of a resin-based multilayer composite material according to claim 1, characterized in that: The diameters of the injection holes and ventilation holes are both 2-3mm.

7. The method for repairing interface defects of a resin-based multilayer composite material according to claim 1, characterized in that: If it is difficult to inject the repair agent, install a sealing rubber pad on the vent hole and assist in injection by vacuuming.

8. The method for repairing interface defects of a resin-based multilayer composite material according to claim 1, characterized in that: The high-frequency vibration of the resin-based multilayer composite material is maintained simultaneously during the injection process.

9. The method for repairing interface defects of a resin-based multilayer composite material according to claim 1, characterized in that: The depths of the injection holes and the vent holes are both greater than the depth of the interface defects, and are both less than the height of the resin-based multilayer composite material.

10. The method for repairing interface defects of a resin-based multilayer composite material according to claim 1, characterized in that: After curing, the residual glue is cleaned and the repaired resin-based multi-layer composite material is subjected to non-destructive testing. The repair is completed after the test is qualified.

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