Pressurizing tool and repairing method for quickly repairing layered falling blocks of grid unit structure

Abstract

The invention discloses a pressurizing tool and a repairing method for quickly repairing layered falling blocks of a grid unit structure, and the pressurizing tool comprises a bottom plate, a cover plate and a concentric-square-shaped block; grating holes are formed in the surface of the cover plate; the grating unit is arranged between the bottom plate and the cover plate; the surfaces of the concentric-square-shaped blocks are arranged in the grating holes, mounting holes are formed in the surfaces of the concentric-square-shaped blocks, stand columns are arranged on the surface of the bottom plate, and the stand columns are arranged in the mounting holes in a penetrating mode. According to the method, the grid units are repaired by installing the pressurizing tool, the cementing porosity can be reduced, the thickness of a cementing repair area can be accurately controlled, meanwhile, the pressurizing tool is convenient to demould by utilizing the characteristic that the ABS plastic material shrinks and deforms when heated, and the repair quality is effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of aircraft structure repair, and more particularly to a method for quickly repairing delamination and falling blocks of a composite material grid unit structure. Background Art

[0002] Grid structures are crucial aircraft components, comprised of numerous uniformly arranged units with unique geometric shapes. They play a crucial role in heat dissipation, ventilation, radar cross-section reduction, and airflow regulation. Composite materials are increasingly being incorporated into aircraft grid structure design due to their lightweight, designable nature, and high specific strength / stiffness. However, during service, composite grid units are susceptible to surface damage such as delamination and fragmentation due to airflow impact, sand and gravel impact, and structural vibration. This poses the risk of damage expansion and functional failure, reducing the safety, reliability, and economic efficiency of the aircraft structure.

[0003] Traditional methods for repairing composite grille structures mainly use mechanical connection and patching repairs. Mechanical connection repair methods have problems such as stress concentration in drilling repairs and errors in mechanical processing and manufacturing. They are prone to introducing new stress concentration areas, resulting in a large weight increase in the repaired structure. For example: Chinese patent CN202111254619.1 (publication date: November 21, 2023) discloses a Boeing 737 passenger aircraft cabin return air grille repair process. This method is to repair the grid's vulnerable parts, the spring support, through reinforcing ribs. The disadvantage is that mechanical connection introduces new stress concentration areas and the repair structure increases in weight.

[0004] Patching repair methods, however, suffer from issues such as long curing cycles and secondary damage from adhesive stripping, making it difficult to quickly repair grid structure damage and improve production efficiency. For example, the March 2018 publication of "Aviation Maintenance and Engineering," pages 57-59, describes a repair method for V2500 engine thrust reverser grid damage. This method involves patching surface damage, but suffers from a long repair cycle.

[0005] Therefore, it is an urgent problem for those skilled in the art to develop a method for quickly repairing delaminated and falling composite grid unit structures with high repair efficiency and easy demoulding. Summary of the Invention

[0006] In view of this, the present invention provides a method for quickly repairing delaminated and chipped composite material grid unit structures with high repair efficiency and easy demoulding.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] Pressurized tooling for rapid repair of delamination and falling of grid unit structures, including:

[0009] bottom plate,

[0010] A cover plate, wherein the surface of the cover plate is provided with grille holes; the grille unit is placed between the bottom plate and the cover plate;

[0011] A circular block, the surface of which is placed in the grille hole, a mounting hole is provided on the surface of the circular block, a column is provided on the surface of the bottom plate, and the column is passed through the mounting hole.

[0012] A method for quickly repairing delamination and falling off of a grid unit structure includes the following repair steps:

[0013] S1: Use visual inspection and non-destructive testing to determine the damage range, and use a marker to mark the repair area and the grid unit length, width and height (Amm×Bmm×Cmm), and use sealing tape to protect the non-repair area;

[0014] S2. According to the size of the grille unit, a dot matrix special pressurizing tool is manufactured. The grille holes on the cover surface are consistent with the size of the grille unit. The circular block is placed in the grille hole, and the column on the base surface is placed in the mounting hole of the circular block, and the column and the mounting hole are tightly fitted.

[0015] S3, testing the fit between the column and the mounting hole to obtain a pressurized fixture;

[0016] S4, according to the type of adhesive selected, weighing the corresponding components according to the ratio, preparing a chopped carbon fiber-adhesive mixed filler, and mixing them evenly;

[0017] S5. Spray a release agent on the surface of the pressurized tooling, and evenly apply the chopped carbon fiber-adhesive mixed filler to the outer surface of the circular block, the surface of the grille holes, and the repair area of ​​the grille unit. Then, install the pressurized tooling and the grille unit, and scrape off any excess mixed filler around it. The gap between the outer contour of the circular block and the grille holes and grille units is the chopped fiber repair filling area.

[0018] S6, using vacuum to remove air bubbles between the carbon fiber-adhesive mixed filler;

[0019] S7, after vacuuming to remove bubbles, visually check whether there is a gap between the circular block and the grid unit. If there is a gap, fill the gap with a mixture of chopped carbon fiber and adhesive. The mixture should be higher than the surface of the pressurized tooling, and use a scraper to smooth the modified surface.

[0020] S8, placing the repaired sample obtained in step S7 into a vacuum bag, installing a heating unit, and determining the curing temperature and time according to the type of adhesive selected to cure the chopped carbon fiber-adhesive mixed filler;

[0021] S9, dismantling the vacuum system and restarting the heating unit to deform and shrink the circular block of the pressurizing tooling, and then dismantling the pressurizing tooling and the heating unit;

[0022] S10, mechanical finishing, to test the quality of adhesive repair.

[0023] Preferably, the pressurized tooling is first designed using a digital model software, and then the model of the pressurized tooling is manufactured using 3D printing technology.

[0024] Preferably, the bottom plate and the cover plate are both made of aluminum alloy, and the circular block is made of ABS plastic.

[0025] Preferably, the length, width, and height of the column are A / 4mm×B / 4mm×2Cmm; the size of the grille holes on the cover plate surface is the same as the size of the grille unit; the length, width, and height of the outer contour of the circular block are 3A / 4mm×3B / 4mm×2Cmm, and the size of the mounting hole is the same as the size of the column. By setting up a pressurized fixture and installing it in the area where the grille unit needs to be repaired, and the grille holes of the cover plate are the same size as the grille unit, and the mounting holes of the circular block are the same size as the column, the column and the circular block fit tightly together, this can reduce the porosity of the repair area, accurately control the thickness of the adhesive layer, improve the adhesive quality, and at the same time control the geometric dimensions of the repair area, so as to achieve rapid filling and repair of the damaged area.

[0026] Preferably, the structure shrinks and deforms when the glass transition temperature Tg of the ABS plastic circular block is less than or equal to the adhesive curing temperature and less than or equal to the ambient temperature of the ABS plastic in use and less than or equal to the high elastic state Tf.

[0027] Preferably, the heating temperature of the heating unit in step S9 is controlled within a range between the glass transition temperature (Tg) and the high-elasticity temperature (Tf) of the ABS plastic of the circular block. By utilizing the heat-shrinkage characteristic of ABS plastic, when demolding is required, the circular block is heated to shrink, thereby enabling the repaired grille unit to be quickly demolded from the pressurized tooling. This ensures the integrity of the grille unit, effectively avoids secondary damage or scrapping of the grille unit due to forced demolding, and improves production efficiency.

[0028] It can be seen from the above technical solution that, compared with the prior art, the present invention provides a pressurized tooling and repair method for quickly repairing delaminated and fallen blocks of a grid unit structure, which has the following beneficial effects:

[0029] (1) By installing a pressurized tool and filling the chopped fiber-adhesive mixed filler in the chopped fiber repair filling area, the thickness of the bonding layer can be precisely controlled and the porosity can be reduced. The damaged area can be quickly filled and repaired, effectively improving the functionality and durability of the composite grid unit structure and extending its service life;

[0030] (2) By utilizing the characteristic of ABS plastic material that it will shrink and deform slightly under heating conditions, the pressurized tooling can be smoothly detached from the grille unit under heating conditions without damaging the newly repaired surface, thus avoiding the risk of secondary damage that may be caused by forced disassembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0032] Figure 1 A schematic diagram of the structure of the pressurizing tooling and the grid unit installation provided by the present invention;

[0033] Figure 2 A schematic diagram of the structure of the grille unit installation provided by the present invention;

[0034] Figure 3 A schematic diagram of the installation process of the pressurized tooling provided by the present invention;

[0035] Figure 4 A side view of the pressurizing tool provided by the present invention.

[0036] Among them, in the figure,

[0037] 1- grid unit;

[0038] 11-Repair area;

[0039] 2- bottom plate;

[0040] 21- pillar;

[0041] 3-cover plate;

[0042] 31-Grille hole;

[0043] 4-Circle block;

[0044] 41-Mounting hole. DETAILED DESCRIPTION

[0045] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0046] The embodiment of the present invention discloses a pressurized tool for quickly repairing delaminated and fallen grid unit structures, comprising:

[0047] Bottom plate 2,

[0048] The cover plate 3 has grille holes 31 on its surface; the grille unit 1 is placed between the bottom plate 2 and the cover plate 3;

[0049] The circular block 4 is placed in the grille hole 31, and the surface of the circular block 4 is provided with a mounting hole 41. The surface of the bottom plate 2 is provided with a column 21, and the column 21 is passed through the mounting hole 41. The four sides of the bottom plate 2, the cover plate 3, and the circular block 4 are all chamfered.

[0050] A method for quickly repairing delamination and falling off of a grid unit structure includes the following repair steps:

[0051] S1, use visual inspection and non-destructive testing to determine the damage range, and use a marker to mark the repair area 11 and the grid unit 1 length, width and height of Amm×Bmm×Cmm, and use sealing tape to protect the non-repaired area;

[0052] S2. According to the size of the grille unit 1, a dot matrix pressurizing tool is manufactured. The grille holes 31 on the surface of the cover plate 3 are the same size as the grille unit 1. The circular block 4 is placed in the grille holes 31. The columns 21 on the surface of the base 2 are placed in the mounting holes 41 of the circular block 4, and the columns 21 and the mounting holes 41 are tightly fitted.

[0053] S3, testing the fit between the column 21 and the mounting hole 41 to obtain a pressurized fixture;

[0054] S4, according to the type of adhesive selected, weighing the corresponding components according to the ratio, preparing a chopped carbon fiber-adhesive mixed filler, and mixing them evenly;

[0055] S5. Spray a release agent on the surface of the pressurized tooling. Use a glass rod or tweezers to evenly apply the chopped carbon fiber-adhesive mixed filler to the outer surface of the circular block 4, the surface of the grille hole 31, and the repair area 11 of the grille unit 1. Install the pressurized tooling and the grille unit 1, and scrape off any excess mixed filler around it. The gap between the outer contour of the circular block 4 and the grille hole 31 and the grille unit 1 is the chopped fiber repair filling area.

[0056] S6, remove bubbles between the carbon fiber-adhesive mixed filler by vacuuming, and the bubble extraction time is ≥40 min;

[0057] S7, after vacuuming to remove bubbles, visually check whether there is a gap between the circular block 4 and the grid unit 1. If there is a gap, use tweezers to grab the chopped carbon fiber-adhesive mixture to fill the gap. The mixture should be higher than the surface of the pressurized tooling, and use a scraper to smooth the modified surface.

[0058] S8, placing the repaired sample obtained in step S7 into a vacuum bag, installing a heating unit, and determining the curing temperature and time according to the type of adhesive selected to cure the chopped carbon fiber-adhesive mixed filler;

[0059] S9, dismantle the vacuum system, start the heating unit again, make the pressurizing fixture circular block 4 deform and shrink, and then dismantle the pressurizing fixture and heating unit;

[0060] S10, mechanical finishing, to test the quality of adhesive repair.

[0061] In order to further optimize the above technical solution, there are multiple ratios of chopped carbon fiber-adhesive mixed fillers. The adhesive is an AB mixed glue, and the two components A and B need to be mixed before the curing effect can be exerted; for example: the mass ratio of adhesive J-349 is component A: component B = 100:30, the mass ratio of adhesive J-352 is component A: component B = 100:30, and the mass ratio of adhesive SY-49 is component A: component B = 50:20.

[0062] In order to further optimize the above technical solution, the pressurized tooling is first designed using CATIA software to create a digital model, and then the model is manufactured using 3D printing technology.

[0063] In order to further optimize the above technical solution, the base plate 2 and the cover plate 3 are both made of aluminum alloy, and the circular block 4 is made of ABS plastic.

[0064] In order to further optimize the above technical solution, the length, width and height of the column 21 are A / 4mm×B / 4mm×2Cmm; the size of the grille hole 31 on the surface of the cover plate 3 is the same as the size of the grille unit 1; the length, width and height of the outer contour of the circular block 4 are 3A / 4mm×3B / 4mm×2Cmm, and the size of the mounting hole 41 is the same as the size of the column 21.

[0065] In order to further optimize the above technical solution, the structure shrinks and deforms when the glass transition Tg of the ABS plastic circular block is ≤ the adhesive curing temperature ≤ the ABS plastic operating environment temperature ≤ the high elastic state Tf.

[0066] In order to further optimize the above technical solution, the heating temperature range of the heating unit in step S9 is controlled to be between the glass transition temperature Tg and the high elastic state temperature Tf of the circular block ABS plastic.

[0067] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0068] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A pressurized tool for quickly repairing delamination and falling blocks of grid unit structures, characterized by: include: bottom plate, A cover plate, wherein a grille hole is provided on the surface of the cover plate; The grille unit is placed between the bottom plate and the cover plate; A circular block, the surface of which is placed in the grille hole, a mounting hole is provided on the surface of the circular block, a column is provided on the surface of the bottom plate, and the column is passed through the mounting hole.

2. A method for quickly repairing delamination and falling blocks of a grid unit structure, characterized in that: The repair steps include the following: S1: Use visual inspection and non-destructive testing to determine the damage range, and use a marker to mark the repair area and the grid unit length, width and height (Amm×Bmm×Cmm), and use sealing tape to protect the non-repair area; S2. According to the size of the grille unit, a dot matrix special pressurizing tool is manufactured. The grille holes on the cover surface are consistent with the size of the grille unit. The circular block is placed in the grille hole, and the column on the base surface is placed in the mounting hole of the circular block, and the column and the mounting hole are tightly fitted. S3, testing the fit between the column and the mounting hole to obtain a pressurized fixture; S4, according to the type of adhesive selected, weighing the corresponding components according to the ratio, preparing a chopped carbon fiber-adhesive mixed filler, and mixing them evenly; S5. Spray a release agent on the surface of the pressurized tooling, and evenly apply the chopped carbon fiber-adhesive mixed filler to the outer surface of the circular block, the surface of the grille holes, and the repair area of ​​the grille unit. Then, install the pressurized tooling and the grille unit, and scrape off any excess mixed filler around it. The gap between the outer contour of the circular block and the grille holes and grille units is the chopped fiber repair filling area. S6, using vacuum to remove air bubbles between the carbon fiber-adhesive mixed filler; S7, after vacuuming to remove bubbles, visually check whether there is a gap between the circular block and the grid unit. If there is a gap, fill the gap with a mixture of chopped carbon fiber and adhesive. The mixture should be higher than the surface of the pressurized tooling, and use a scraper to smooth the modified surface. S8, placing the repaired sample obtained in step S7 into a vacuum bag, installing a heating unit, and determining the curing temperature and time according to the type of adhesive selected to cure the chopped carbon fiber-adhesive mixed filler; S9, dismantling the vacuum system and restarting the heating unit to deform and shrink the circular block of the pressurizing tooling, and then dismantling the pressurizing tooling and the heating unit; S10, mechanical finishing, to test the quality of adhesive repair.

3. The method for quickly repairing delamination and falling off of a grid unit structure according to claim 2 is characterized in that: The pressurized tooling is first designed using digital model software, and then the model of the pressurized tooling is manufactured using 3D printing technology.

4. The method for quickly repairing delamination and falling off of a grid unit structure according to claim 2 is characterized in that: The base plate and cover plate are made of aluminum alloy, and the circular block is made of ABS plastic.

5. The method for quickly repairing delamination and falling off of a grid unit structure according to claim 2 is characterized in that: The length, width and height of the column are A / 4mm×B / 4mm×2Cmm; the size of the grille holes on the cover surface is the same as the size of the grille unit; the length, width and height of the outer contour of the circular block are 3A / 4mm×3B / 4mm×2Cmm, and the size of the mounting hole is the same as the size of the column.

6. The method for quickly repairing delamination and falling off of a grid unit structure according to claim 4 is characterized in that: The structure shrinks and deforms when the glass transition Tg of the ABS plastic circular block is ≤ the adhesive curing temperature ≤ the ambient temperature of the ABS plastic use ≤ the high elastic state Tf.

7. The method for quickly repairing delaminated and falling grid unit structures according to claim 2 is characterized in that: In step S9 , the heating temperature range of the heating unit is controlled to be between the glass transition temperature Tg and the high elastic state temperature Tf of the circular block ABS plastic.

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