Thermoset composite laminate and method of delamination repair thereof

Abstract

The application provides a thermosetting composite material laminate and a delamination repair method thereof, which comprises the following steps: marking the position and depth of a defect area; then drilling a glue hole with a depth exceeding the delamination depth; placing a solid-state body resin layer with air permeability at room temperature on the glue hole; laying a glue-impermeable isolation layer on the resin layer to seal the resin in the defect area and making a vacuum bag on the product surface; performing vacuumizing at room temperature in a hot press tank, then increasing the temperature to melt the resin into a low-viscosity liquid, and then pressurizing to extrude and permeate the resin into the delamination defect gap, and completing the delamination defect repair after the resin solidification. Compared with the existing repair method, the application has small damage to the product, does not need professional repair equipment, has simple process, low cost, wide application range, can repair delamination defects at any position, has strong permeation force under vacuum state and pressurization, and has good repair effect on small delamination gaps.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of composite material repair process, in particular, to a thermosetting composite material laminate and a delamination repair method thereof. BACKGROUND

[0002] The thermosetting composite material laminate is widely used in various high-performance structures and functional components of aviation and aerospace. The thermosetting composite material laminate, especially the complex-shaped structure or large component, is prone to local delamination defects after curing molding due to improper local laying or uneven pressing, etc. The delamination defects affect the performance of the product, which may cause product degradation or scrap and other major losses. Therefore, the repair of delamination defects of the thermosetting composite material laminate has high economic value.

[0003] The existing repair methods in the existing data mainly include the digging repair method and the edge glue injection method, which both need to use professional equipment and have high requirements for operation technology. Improper repair may cause structural damage, and the repair has great limitations and is difficult to be applied to local repair of complex structures.

[0004] Patent document CN104827738A (application number: 201510176041.0) discloses a composite material laminate repair method. The composite material laminate repair method comprises the following steps: step 1: a step of matching a mixed repair material with the same stiffness as the position to be repaired of the composite material laminate; and step 2: a step of repairing the position to be repaired by the mixed repair material. SUMMARY

[0005] In view of the defects in the prior art, the present application aims to provide a thermosetting composite material laminate and a delamination repair method thereof.

[0006] According to the present application, a delamination repair method of a thermosetting composite material laminate is provided, which comprises the following steps:

[0007] Step S1: calibrating the delamination position and depth of the defect area;

[0008] Step S2: making a glue hole in the delamination area;

[0009] Step S3: laying a resin layer on the glue hole;

[0010] Step S4: laying an isolation auxiliary layer on the resin layer;

[0011] Step S5: making a vacuum bag on the surface of the composite material covering the delamination area;

[0012] Step S6: vacuumizing and exhausting at room temperature;

[0013] Step S7: heating and melting the liquefied resin;

[0014] Step S8: pressurize to penetrate resin into delamination gap;

[0015] Step S9: demold and trim after curing, and nondestructive testing.

[0016] Preferably, the glue-filling holes are blind holes with a depth exceeding the delamination depth, a diameter of φ1mm-φ3mm, and a spacing of 10-30mm.

[0017] Preferably, the method further comprises polishing and roughening the side wall of the glue-filling hole to expose the delamination gap.

[0018] Preferably, the step S3 comprises laying a solid-state body resin layer with air permeability at room temperature on the glue-filling hole, and using a hardened felt or a hard glue film with air passages to absorb the hardening of the body glue.

[0019] Preferably, the step S4 comprises laying an isolation auxiliary layer on the resin layer, which is one or a combination of a glue-impermeable isolation film, an air-permeable release cloth, and an air-permeable felt, to seal the resin in the defect area.

[0020] Preferably, the step S6 comprises vacuumizing at room temperature in a hot press tank, and the vacuum degree of the vacuumized exhaust is better than -0.095MPa.

[0021] Preferably, the step S7 comprises heating and melting the resin into a low-viscosity liquid, and the temperature for heating and melting the liquefied resin is a temperature at which the viscosity of the resin after melting is ≤0.3Pa.S.

[0022] Preferably, the step S8 comprises pressurizing to penetrate resin into the delamination gap at a pressure of 0.1-1.5Mpa.

[0023] Preferably, the step S8 comprises pressurizing to penetrate resin into the delamination gap by hot press or mechanical pressurization.

[0024] According to the present application, a thermosetting composite material laminated board is provided, which is repaired by the above-mentioned thermosetting composite material laminated board delamination repair method.

[0025] Compared with the prior art, the present application has the following beneficial effects:

[0026] 1. The present application adopts a repair method of drilling glue-filling holes to penetrate glue into the delamination defect gap, which greatly reduces the influence of repair on the structure and performance of the product and the appearance compared with the repair method of digging;

[0027] 2. The present application uses a hardened felt or a reticular or corrugated hard glue film with air passages that is solid at room temperature and has low viscosity at high temperature to replace the complex process of vacuum introducing liquid resin, which greatly simplifies the operation and reduces the cost;

[0028] 3、The application adopts normal temperature vacuumizing, non-glue permeable film auxiliary and high temperature pressurizing to realize high pressure glue injection to the non-edge area in vacuum state, compared with the existing edge glue injection repair method, the repair cost is greatly reduced, and the application range is increased.

[0029] 4、The application has small product damage, does not need professional repair equipment, simple process, low cost, wide application range, can repair layered defects at any position, strong penetration force in vacuum state, good repair effect for small layered gap;

[0030] 5、The application provides a thermosetting composite material laminate layering repair method, which is suitable for repairing local layering defects of complex or large and small thermosetting composite material laminates after molding, and solves the problem that local layering defects of the thermosetting composite material laminate after molding are difficult to repair. BRIEF DESCRIPTION OF DRAWINGS

[0031] Other features, objects and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments, made with reference to the accompanying drawings:

[0032] Figure 1 The application is an embodiment process diagram.

[0033] Figure 2 The application is an auxiliary material laying schematic diagram.

[0034] In the figure, 201 is a composite material laminate, 202 is a layering defect, 203 is a glue filling hole, 204 is a hardened felt saturated with a resin body, 205 is a glue impermeable release cloth, 206 is a breathable release cloth, and 207 is a vacuum bag. DETAILED DESCRIPTION

[0035] The application will be described in detail below with reference to specific embodiments. The following embodiments will help those skilled in the art to further understand the application, but do not limit the application in any form. It should be pointed out that, for those skilled in the art, without departing from the concept of the application, a number of changes and improvements can be made. These all belong to the protection scope of the application.

[0036] Example 1

[0037] The application is aimed at the current situation that the structure of complex or large thermosetting composite material laminates has local layering after molding, affects product performance, causes great economic loss, and there is no effective repair method. A thermosetting composite material laminate layering repair method is proposed, which solves the problem that local layering defects of the thermosetting composite material laminate after molding are difficult to repair.

[0038] The method for repairing delamination of the thermosetting composite laminate, as shown in the figure, comprises the following main steps: Figure 1

[0039] Step 1: calibrate the delamination position and depth;

[0040] Step 2: make a glue hole in the delamination area;

[0041] Step 3: lay a resin layer on the glue hole;

[0042] Step 4: lay an isolation auxiliary layer on the resin layer;

[0043] Step 5: make a vacuum bag on the composite material surface outside the delamination area;

[0044] Step 6: vacuum exhaust at room temperature;

[0045] Step 7: melt and liquefy the resin at a high temperature;

[0046] Step 8: pressurize to penetrate the resin into the delamination gap;

[0047] Step 9: demold and trim after curing, and perform non-destructive testing.

[0048] Specifically, the glue hole is a blind hole with a depth exceeding the delamination depth, a hole diameter of φ1mm-φ3mm, and a spacing of 10-30mm.

[0049] Specifically, the glue hole side wall is polished and roughened and cleaned to expose the delamination gap.

[0050] Specifically, the resin layer laid on the glue hole is a hardened felt saturated with the body glue or a hard glue film with air passages in a mesh or corrugated shape.

[0051] Specifically, the isolation auxiliary layer laid on the resin layer is one or a combination of several of the following: a glue-impermeable isolation film and a gas-permeable release cloth, and a gas-permeable felt.

[0052] Specifically, the vacuum degree of the vacuum exhaust at room temperature is better than -0.095MPa.

[0053] Specifically, the temperature for melting and liquefying the resin is a temperature at which the viscosity of the resin after melting is ≤0.3Pa.S.

[0054] Specifically, the pressure for pressurizing to penetrate the resin into the delamination gap is 0.1-1.5Mpa.

[0055] Specifically, the pressurizing mode for pressurizing to penetrate the resin into the delamination gap is hot-pressing tank pressurizing or mechanical pressurizing.

[0056] ​According to the present invention, a thermosetting composite material laminate is repaired by the above-described thermosetting composite material laminate delamination repair method.

[0057] This invention provides a method for repairing delamination in thermosetting composite laminates, applicable to repairing local delamination defects in complex or large / small thermosetting composite laminates after molding, solving the problem of difficult repair of local delamination defects in thermosetting composite laminates after molding.

[0058] Example 2

[0059] Example 2 is a preferred example of Example 1.

[0060] like Figure 2 As shown in the illustration, this embodiment further explains the delamination repair method for thermosetting composite laminates. The laminate, with an outer profile of φ2000mm × 1000mm, is a supporting structure for a T800 / epoxy resin composite laminate 201. It has a delamination defect 202 at the lower flange. The flange wall thickness is 8mm, the defect size is 30mm × 70mm, and the depth is 2mm from the surface, located at the R-corner where it connects to the flange. The specific repair process for this delamination defect 202 is as follows.

[0061] According to the production process documents, ultrasonic non-destructive testing was performed on the flange defect location according to GJB1038.1A to mark the defect range and depth. Then, within the marked flange defect area, a φ1.5mm drill bit with diamond abrasive on its surface was used to drill glue-filling holes 203 at 15mm×15mm intervals with a depth of 5-6mm. After drilling, the holes were cleaned with compressed air and anhydrous acetone to fully expose the delamination gaps. A 1-3mm thick layer of hardened felt 204 saturated with bulk resin was placed on the glue-filling holes, with the area of ​​the hardened felt 204 saturated with bulk resin 10-20mm larger than one side of the defect. Next, one layer of impermeable release cloth 205 and one layer of breathable release cloth 206 were placed sequentially on the adhesive layer, with the impermeable release cloth 205 covering the hardened felt saturated with bulk resin 204. Finally, a vacuum bag 207 was prepared on the carbon fiber surface for the repair area. The product was placed in an autoclave, and a thermocouple was connected to control the temperature. A vacuum was drawn at room temperature to a pressure better than -0.095 MPa and maintained for ≥15 minutes. Then, the temperature was raised to 120±10℃ and held for 20 minutes to convert the resin into a low-viscosity liquid resin. The autoclave was then pressurized to 0.3 MPa and held for 1 hour, allowing the low-viscosity liquid resin, encapsulated in an impermeable release liner, to penetrate into the delamination defects. The vacuum was then stopped, and the temperature was raised to 150℃ and held for 3 hours. After cooling to room temperature, the product was demolded. After repairing the lower flange, ultrasonic non-destructive testing was performed again. The results showed that the defect area met the Class A requirements of GJB2895.

[0062] The specific embodiments of the present application are described above. It needs to be understood that the present application is not limited to the specific embodiments described above, and various changes or modifications can be made by those skilled in the art within the scope of the claims, which does not affect the essential content of the present application. The embodiments of the present application and the features in the embodiments can be combined with each other at will without conflict.

Claims

1. A method of delamination repair of a thermoset composite material laminate characterized in that, The method comprises the following steps: S1: Marking the delamination position and depth of the defect area; S2: Making a glue hole in the delamination area; The glue hole is a blind hole with a depth exceeding the delamination depth; S3: Laying a resin layer on the glue hole; S4: Laying an isolation auxiliary layer on the resin layer; S5: Making a vacuum bag on the surface of the composite material covering the delamination area; S6: Vacuumizing at room temperature; S7: Melting the resin at a high temperature; S8: Pressurizing the resin to penetrate into the delamination gap; S9: Demoulding, trimming and non-destructive testing after curing; The method further comprises polishing and roughening the side wall of the glue hole to expose the delamination gap. The step S3 comprises laying a solid-state body resin layer with air permeability on the glue hole, which is used for absorbing the hardening felt of the body glue or the hard glue film with air passage.

2. The thermoset composite laminates delamination repair method according to claim 1, characterized in that, The diameter of the glue hole is φ1mm-φ3mm, and the interval is 10-30mm.

3. The thermoset composite laminates delamination repair method according to claim 1, wherein, The step S4 comprises laying an isolation auxiliary layer on the resin layer, which is a combination of one or more of the following: impermeable isolation film, air-permeable release cloth and air-permeable felt, so as to seal the resin in the defect area.

4. The thermoset composite laminates delamination repair method according to claim 1, wherein, The step S6 comprises vacuumizing at room temperature in a hot press tank.

5. The thermoset composite laminates delamination repair method according to claim 1, wherein, The step S7 comprises melting the resin at a high temperature to form a low-viscosity liquid, and the temperature of the melted resin is a temperature at which the viscosity of the resin is less than or equal to 0.3Pa.S.

6. The thermoset composite laminates delamination repair method according to claim 1, wherein, The step S8 comprises pressurizing the resin to penetrate into the delamination gap, and the pressure is 0.1-1.5Mpa.

7. The thermoset composite laminates delamination repair method according to claim 1, wherein, The step S8 comprises pressurizing the resin to penetrate into the delamination gap, and the pressurizing mode is hot press tank pressurizing or mechanical pressurizing.

8. A thermoset composite laminate panel characterized by, The repaired product is repaired by the method for repairing the delamination of the thermosetting composite material laminate according to any one of claims 1-7.

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