Method for improving rib r zone wrinkle defects

Abstract

The application discloses a kind of R area wrinkle defect improvement method of rib in the technical field of composite rib processing, sequentially carry out mould cleaning coating release agent, prepreg is according to presetting and every four layers vacuum pre-extraction, surface can be peeled off cloth is separated after being arranged to R area, and vacuum packaging is set, two-stage curing is executed in transfer hot press tank, finally demoulding detects internal defect, and through the three-dimensional data model of defective product, based on R area defect, it is repaired and filled.The application controls wrinkle by double path, sprays temporary interface modifier containing silane coupling agent and polyethylene glycol before curing, reduces fiber slip by low-temperature lubrication, and the first stage low-pressure compaction of two-stage curing makes compressed fiber rearrangement and eliminates micro-wrinkle, while thick air-permeable felt strip forms high-pressure wave crest, forces resin directional discharge, reduces rich glue rate and solves fiber buckling instability problem.

Description

Technical Field

[0001] This invention relates to the field of composite material rib processing technology, and in particular to a method for improving wrinkle defects in the R region of ribs. Background Technology

[0002] Composite material stiffeners, as key reinforcing components in aircraft structures, leverage their lightweight and high-strength properties to form a highly efficient synergy with the main structure, such as the skin. This significantly enhances the bending, shear, and buckling resistance of critical components like wings, fuselages, and tail sections, ensuring structural stability and integrity under complex aerodynamic loads and extreme conditions. Furthermore, their design flexibility allows for on-demand reinforcement of local stiffness, optimized force transmission paths, effective stress dispersion, and extended structural fatigue life. In addition, composite material stiffeners provide excellent environmental corrosion resistance and impact protection, offering reliable support and protection for internal pipelines and wiring. They are a crucial technological support for achieving weight reduction, improved flight performance, and enhanced safety and reliability in aircraft structures.

[0003] However, existing technologies have some problems: during the autoclave molding process of composite material ribs, wrinkles are prone to occur in the R-zone (i.e., the bending transition area between the rib and the skin corner). This is mainly due to the complex coupling effect between the material's own properties and the molding process: on the one hand, composite materials have significant anisotropy, with extremely high modulus and strength along the fiber direction, while the transverse and shear moduli are much lower. When the prepreg is bent and laid at a large angle in the R-zone, the outer layer fibers attempt to elongate due to stretching, while the inner layer fibers attempt to shorten due to compression. However, the fluidity of the resin matrix and the friction between the fibers hinder this free deformation, causing the inner layer fibers to wrinkle. Under compression, local buckling and instability occur, leading to the formation of micro-wrinkles perpendicular to the fiber direction. On the other hand, autoclave molding relies on the combined effect of temperature and pressure to make the resin flow and cure. If the pressure is unevenly applied, the heating / cooling rate is too fast, or the R-zone is laid too tightly, or the prepreg cutting angle deviates from the theoretical profile, it will exacerbate the difficulty of fiber slippage during bending, making it impossible for compressive stress to be effectively released through the resin. Ultimately, under the instability stress concentration caused by the difference in fiber length between the inner and outer layers, the macroscopic manifestation is visible wrinkle defects, which seriously affect the structural mechanical properties and load-bearing safety. Therefore, we propose a method to improve the wrinkle defects in the R-zone of the reinforcing rib. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a method for improving the wrinkle defects in the R-zone of reinforcing ribs. By synergistically suppressing fiber buckling through interface control, pressure optimization, and gradient repair, the wrinkle defects in the R-zone are eliminated.

[0005] The objective of this invention is achieved as follows: a method for improving wrinkle defects in the R region of a rib, comprising the following steps: S1, Mold treatment: Based on the aluminum alloy C-type mold, acetone cleaning and anhydrous ethanol wiping are performed in sequence, and a release agent is applied to the working surface of the mold and then dried at room temperature; S2, Prepreg Laying: According to the preset number of layers and angle, the prepreg is cut using an automatic fabric cutting machine and laid in a clean room. During the laying process, vacuum pre-extraction is performed for more than 15 minutes after every 4 layers of prepreg are laid. S3, Encapsulation: After the prepreg is laid, a peelable fabric is laid on the surface of the prepreg and the R area is isolated. Then, a vacuum encapsulation structure is set up. S4, Curing: Transfer the mold to the effective temperature range of the autoclave, and after passing the leak test, implement a two-stage heating and pressurization strategy until curing is complete and the mold is demolded. S5, detects internal defects in the R area and repairs defective parts.

[0006] Optionally, the vacuum sealing structure includes a porous isolation membrane, a non-porous isolation membrane, a breathable felt, and a vacuum bag; When laying the vacuum sealing structure, the porous isolation membrane, non-porous isolation membrane, breathable felt layer, and vacuum bag are laid in sequence.

[0007] Optionally, the laying of the breathable felt layer specifically involves: Multiple breathable felt strips based on the part profile are prepared and laid along the geometric profile of the prepreg blank; The breathable felt strip is placed above the non-porous isolation membrane, and the breathable felt strip is kept 10mm to 50mm away from the edge of the part, and the breathable felt strip does not contact the surface of the part.

[0008] Optionally, the breathable felt layer may further include thick breathable felt strips; The thick breathable felt strip is formed by stacking and pressing 2 to 3 layers of the breathable felt strip, and is set in accordance with the outline of the R area; The thick breathable felt strips are laid on the top layer of the breathable felt, surrounding the outline of the R area.

[0009] Optionally, before curing in step S4, a modifier is further applied, specifically: After the prepreg is laid up, a temporary interface modifier is evenly and in small amounts sprayed onto the R area using a low-pressure sprayer equipped with a fine-nozzle nozzle. After spraying, let it stand for 5 to 10 minutes before proceeding to step S4.

[0010] Optionally, the temporary interface modifier includes a silane coupling agent solution and a polyethylene glycol solution; The temporary interface modifier is a diluted aqueous solution.

[0011] Optionally, in step S4, the two-stage heating and pressurization strategy specifically refers to: Phase 1: Rapid heating and initial high-pressure compaction: Heat the workpiece to 60~80℃ and hold for 30~35 minutes, with a heating rate of 1.5~2.5℃ / min; Then, pressurize to 0.2~0.3MPa and hold for 20~25 minutes; Phase Two: Gelping and Curing After the pressure holding period is completed, increase the pressure to 0.6~0.65MPa and hold the pressure at this level for 30~40 minutes. Then, the temperature is raised to 175~180℃ and held at that temperature and pressure for 90~120 minutes; Continue until the part is completely cured.

[0012] Optionally, the process for detecting internal defects in region R in step 5 is as follows: S51, visually inspect the surface quality of the R area of ​​the part, and combine it with ultrasonic C-scan to identify internal structural defects, and classify the part as qualified or unqualified. S52 performs a deep 3D scan on non-conforming parts to determine the depth, area, and 3D morphology of defects and construct a 3D data model. S53, based on the most obvious defect in the R area, cuts in and scrapes an inner cavity that gradually deepens towards the center of the R area, and polishes and chemically cleans the surface of the inner cavity; S54, prepare two composite matrix resins with different performance gradients, and fill them in layers in the inner cavity; S55, a small vacuum bag is laid on the repair surface and sealed and vacuumed, and a release film is placed at the junction of the repair area and the adjacent parent material. S56, after the second curing is performed, internal defect detection is performed again.

[0013] Optionally, in step S53, the aperture of the inner cavity gradually decreases from the outside to the inside; The inner surface of the cavity is set with a continuous gradient at a preset micro-angle, which is 1~5°.

[0014] Optionally, the preparation of the two composite matrix resins with different performance gradients specifically involves: A resin for filling the bottom layer region of a cavity; Another type of resin is used to fill the upper region of the cavity, the resin in the upper region having a lower viscosity than the resin in the lower region.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. Controlling the root cause of wrinkles through a dual-pathway approach: First, a temporary interface modifier containing silane coupling agent and polyethylene glycol is sprayed before curing. Its low-temperature lubrication properties significantly reduce fiber slippage resistance. Combined with the low-pressure compaction window of the first stage of two-stage curing, the surface compressed fibers in the R zone are rearranged without excessive friction, eliminating micro-wrinkles. At the same time, flow is restricted by thick breathable felt strips, and local high-pressure peaks are formed during vacuuming, forcing excess resin to be discharged directionally along a preset path, reducing the resin content, thereby solving the problem of fiber buckling instability caused by resin retention.

[0016] 2. By setting up a detection and repair process, relying on ultrasonic C-scan three-dimensional modeling and gradient internal cavity scraping technology, after quantifying the defect morphology, a layered filling of high-viscosity resin at the bottom and low-viscosity resin at the top is adopted, combined with the interlocking repair of the micro-angle pore diameter gradient internal cavity, to ensure the porosity after repair, improve the interface bonding strength, and finally realize the elimination of wrinkle defects in the whole cycle from molding to repair, meeting the high reliability requirements of the main load-bearing components of aerospace composite materials. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the overall structure of the reinforcing bars provided by the present invention.

[0019] Figure 2 This is a schematic diagram of the method for improving the wrinkle defect in the R region of the rib provided by the present invention.

[0020] Figure 3 This is a schematic diagram of the process for detecting and repairing parts provided by the present invention.

[0021] Figure 4 This is a framework diagram of the method for improving the wrinkle defect in the R region of the rib provided by the present invention. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] like Figures 1 to 4The method for improving wrinkle defects in the R region of a rib, as shown, includes the following steps: S1, Mold treatment: Based on the aluminum alloy C-type mold, acetone cleaning and anhydrous ethanol wiping are performed in sequence, and a release agent is applied to the working surface of the mold and then dried at room temperature; S2, Prepreg Laying: According to the preset number of layers and angle, the prepreg is cut using an automatic fabric cutting machine and laid in a clean room. During the laying process, vacuum pre-extraction is performed for more than 15 minutes after every 4 layers of prepreg are laid. S3, Encapsulation: After the prepreg is laid, a peelable fabric is laid on the surface of the prepreg and the R area is isolated. Then, a vacuum encapsulation structure is set up. S4, Curing: Transfer the mold to the effective temperature range of the autoclave, and after passing the leak test, implement a two-stage heating and pressurization strategy until curing is complete and the mold is demolded. S5, detects internal defects in the R area and repairs defective parts.

[0024] Further, the specific process of step S1 is as follows: select a C-type mold made of aluminum alloy, remove the tooling oil seal, clean the tooling three times with acetone, with an interval of at least 10 minutes between each cleaning, and place it in an oven to heat at (180~200)℃ / (3~4)h after coating. Pour anhydrous ethanol onto a clean wiping paper or cloth and wipe the tooling three times as needed, with an interval of at least 10 minutes between each wipe. Wipe away dust, particles and other excess materials that may affect the surface quality of the molded parts, and keep the mold surface smooth and clean. Apply a layer of release agent to the working surface and allow it to dry at room temperature for at least 30 minutes after the work is completed.

[0025] Furthermore, firstly, for aluminum alloy mold substrates, it is necessary to thoroughly remove protective layers such as tooling oil seals. This is achieved through three cleaning processes using acetone, which utilizes its strong dissolving properties to decompose and remove grease, fingerprints, and organic residues from the mold surface. High-temperature treatment is used to completely evaporate any remaining acetone solvent, and a thermochemical reaction activates the hydroxyl groups on the aluminum alloy surface, forming a micro-active layer that enhances the adhesion of subsequent coatings. Secondly, ethanol, as a low surface tension polar solvent, is used to target and remove the inorganic particles, dust and other microscopic impurities remaining after acetone cleaning by wiping three times, ensuring that the surface of the mold meets the surface finish requirement of Ra≤0.4μm. The wiping process must be carried out unidirectionally along the curvature of the mold to avoid secondary contamination. In particular, the cleanliness control of complex curved surfaces such as the R area needs to be strengthened. Finally, a special release agent is uniformly coated on the working surface and cured at room temperature. During this stage, the coating needs to form a uniform and continuous nanoscale protective film, which covers the microscopic unevenness of the mold surface through molecular-level spreading. The curing process ensures that the release agent solvent completely evaporates, forming a functional interface with low surface energy and high chemical inertness, which avoids the risk of resin-metal adhesion and ensures the integrity of the demolded part.

[0026] Specifically, vacuum sealing structures include porous isolation films, non-porous isolation films, breathable felts, and vacuum bags; When laying the vacuum sealing structure, the porous isolation membrane, non-porous isolation membrane, breathable felt layer, and vacuum bag are laid in sequence.

[0027] Furthermore, the vacuum packaging structure strictly follows the sequential laying process, and its core logic lies in constructing a functional closed loop of gas flow → resin barrier → pressure homogenization → environmental sealing. The porous separator membrane is located adjacent to the prepreg and discharges resin volatiles and encapsulates gas through its microporous structure, preventing internal pores in the part. The non-porous separator membrane acts as a secondary barrier, trapping liquid resin discharged from the porous membrane to prevent leakage and contamination of the vacuum system and to isolate external impurities. The breathable felt layer is located in the middle, and its three-dimensional mesh structure absorbs trace amounts of leaked resin while uniformly transmitting the external pressure of the autoclave to complex areas of the part (such as the R-zone), eliminating the risk of pressure concentration. The vacuum bag, as the outermost sealing layer, creates negative pressure during vacuuming to ensure the part fits tightly against the mold, and during pressurization, it uniformly transmits the high-pressure medium through the breathable felt to the entire molding interface. Ultimately, this achieves effective gas discharge, controllable resin flow, precise pressure transmission, and stable maintenance of the vacuum environment, ensuring high-quality molding of complex composite material components without pores or wrinkles.

[0028] Specifically, the laying of the breathable felt layer is as follows: Multiple breathable felt strips based on the part profile are prepared and laid along the geometric profile of the prepreg blank; The breathable felt strip is placed on top of the non-porous isolation membrane, with a distance of 10mm to 50mm between the breathable felt strip and the edge of the workpiece, and the breathable felt strip does not contact the surface of the workpiece.

[0029] Furthermore, firstly, the gap reserved at the edge creates a low-pressure gas channel. When vacuuming, the gas and resin volatiles wrapped around the edge of the prepreg can flow freely to the vacuum pipeline through the gap, avoiding local high-pressure bubbles or interlayer delamination caused by the closed space. At the same time, the gap provides a buffer for resin flow, preventing fiber buckling caused by rapid resin flow in complex contours such as the R-zone.

[0030] Secondly, the non-porous membrane is placed in an isolated position to ensure that the non-porous membrane traps any liquid resin that may seep out from the edge of the prepreg, preventing it from contaminating the breathable felt and vacuum system. The breathable felt strips are suspended independently above as a pressure transmission medium, avoiding resin adsorption caused by direct contact with the workpiece, which could lead to localized glue shortages or damage to fiber orientation due to mechanical friction. In addition, the pressure buffer strip composed of strip structure, when pressurized in the autoclave, the breathable felt strip compensates for the geometric deviation between the part and the vacuum bag through elastic deformation, and evenly diffuses the external high pressure to the whole part, eliminating wrinkle defects caused by edge stress concentration.

[0031] Specifically, the breathable felt layer also includes thick breathable felt strips; The thick breathable felt strip is made of 2 to 3 layers of breathable felt strips stacked and pressed together, and is set to correspond to the outline of the R area; Thick, breathable felt strips are laid on top of the breathable felt, surrounding the outline of the R area.

[0032] Furthermore, this application divides the breathable felt layer into two parts: ordinary edge ventilation strip: still using breathable felt strips of conventional width, laid along the outer edge of the part; R-zone specific high-density thick breathable felt strip: Cut a breathable felt strip that perfectly matches the outline of the R-zone, but is slightly wider, such as 20-30mm wider. Choose a breathable material with a higher mesh count and greater density, or use multiple layers of ordinary breathable felt to stack as the pressure reinforcement core of the R-zone. During installation, place this high-density, thick, breathable felt strip on the top layer of the breathable felt, close to the isolation membrane, so that it surrounds the entire R zone, while the surrounding regular ventilation strips are laid on its outer side. The thick breathable felt strip and the regular breathable felt strip form a flow limiter. When the vacuum system starts to pump air, the gas is discharged from the inside of the part (especially the R area) and must first pass through the high-density core strip. The flow resistance of the high-density core strip is much greater than that of the surrounding regular exhaust strip. According to Bernoulli's principle in fluid mechanics, the static pressure of a fluid increases when it passes through a narrow or high-resistance channel. Therefore, directly below the R zone, a local, instantaneous pressure peak is formed because the gas discharge channel is restricted by the high-density core strip. The peak value of this pressure peak is 20% to 40% higher than the uniform gas pressure inside the vacuum bag, which means that a virtual high pressure of much greater than 0.65 MPa is formed on the R zone. This forces excess resin to flow quickly to the exhaust channel along the preset path instead of lingering in the R zone, reducing the resin content in the R zone and avoiding a decrease in local strength.

[0033] Specifically, before curing in step S4, a modifier is also applied, specifically: After the prepreg is laid up, a temporary interface modifier is uniformly and in small amounts sprayed onto the R area using a low-pressure sprayer equipped with a fine nozzle. The temporary interface modifier includes a silane coupling agent solution and polyethylene glycol. The temporary interface modifier is a diluted aqueous solution. After spraying, let it stand for 5 to 10 minutes before proceeding to step S4.

[0034] Furthermore, at the initial curing temperature of 60~80℃, the modifier can effectively reduce the energy efficiency of the fiber surface, temporarily weaken the physical adsorption and van der Waals forces between the fiber and the resin matrix, and form a low-friction interface lubrication layer. When the temperature exceeds 110~120℃, the effect will disappear rapidly, and the fiber and resin will restore normal interfacial bonding. At this time, under the dual action of virtual high pressure and low friction interface, the fibers in the R region will smoothly slide and rearrange themselves under pressure, thereby eliminating the slippage tendency from the root. When the temperature exceeds 120°C, the lubricating layer fails, the fibers are locked in a new position, and then the resin begins to gel and completes final curing, forming a wrinkle-free, tightly structured part.

[0035] Furthermore, firstly, the organic end of the silane coupling agent is covalently bonded to the epoxy resin, while the inorganic end is adsorbed onto the carbon fiber surface through hydrogen bonds, thus constructing a high-adhesion-strength transition layer in the early stage of curing and suppressing the risk of interfacial delamination caused by abrupt curvature changes in the R region. Secondly, polyethylene glycol, as a surfactant molecular chain segment, forms a superhydrophilic molecular film on the fiber surface during the standing period, which can reduce the resin / fiber interfacial tension by 20% to 30%, significantly improve the resin's wetting depth in the R-zone grooves and fiber bundles, and reduce micropore residue.

[0036] In addition, the volatility of the aqueous solution system means that the modifier remains active only for 5 to 10 minutes before curing. This avoids permanent chemical modification that alters the material's intrinsic properties. Furthermore, through the dynamic regulation mechanism of interfacial energy, the temporarily weakened interfacial viscosity of the modified layer promotes resin flow and filling when the autoclave is pressurized. During high-temperature curing, the cross-linking reaction between the silane coupling agent and the resin gradually restores the interfacial strength, thereby increasing the interfacial bonding strength of the R-zone and reducing porosity.

[0037] Specifically, in step S4, the two-stage heating and pressurization strategy is as follows: Phase 1: Rapid heating and initial high-pressure compaction: Heat the workpiece to 60~80℃ and hold for 30~35 minutes, with a heating rate of 1.5~2.5℃ / min; Then, pressurize to 0.2~0.3MPa and hold for 20~25 minutes; Phase Two: Gelping and Curing After the pressure holding period is completed, increase the pressure to 0.6~0.65MPa and hold the pressure at this level for 30~40 minutes. Then, the temperature is raised to 175~180℃ and held at that temperature and pressure for 90~120 minutes; Continue until the part is completely cured.

[0038] Furthermore, the two-stage heating and pressurization strategy optimizes the molding quality of complex curved surfaces in the R region by controlling the resin rheological behavior and pressure transmission sequence. The first stage is the low viscosity window period before resin gelation: rapid heating softens the resin and reduces its viscosity, providing sufficient interlayer slip time for the prepreg, while low pressure avoids excessive resin loss due to premature high pressure, ensuring that the fiber bundles can rearrange to fit the mold contour in the curvature change area, eliminating the risk of initial wrinkles. At the same time, the pressure in this stage causes interlayer air to migrate in a direction along the preset exhaust path, avoiding air bubbles from being trapped in the R area. In the second stage, the pressure is increased to 0.6~0.65MPa and the temperature is simultaneously raised to the curing temperature (175~180℃). The final high-pressure compaction is completed at the resin gelation critical point. At this time, the resin viscosity increases sharply. The high pressure forces the residual gas and excess resin to be discharged quickly, while fixing the slipped fiber layer to prevent the fiber from rebounding due to thermal expansion during the curing process. The synergistic effect of high temperature and high pressure increases the fiber volume fraction in the R zone, thereby reducing the wrinkle rate in the R zone and improving the interfacial bonding strength compared to the traditional single-stage process.

[0039] Specifically, the process for detecting internal defects in area R in step 5 is as follows: S51, visual inspection of the surface quality of the R area of ​​the part, combined with ultrasonic C-scanning of internal structural defects, to classify qualified and unqualified parts. Visual inspection combined with ultrasonic C-scanning can accurately locate external and internal defects. S52 performs in-depth three-dimensional scanning on non-conforming parts to determine the depth, area, and three-dimensional morphology of defects, and constructs a three-dimensional data model to quantify the depth, area, and morphology of wrinkles, providing a geometric basis for repair. S53, starting from the point where the defect in the R region is most obvious, scrapes out an inner cavity that gradually deepens towards the center of the R region, and then polishes and chemically cleans the surface of the inner cavity. The diameter of the inner cavity gradually decreases from the outside to the inside; The inner surface of the cavity is set with a continuous gradient of a preset micro-angle, which is 1~5°. S54, prepare two composite matrix resins with different performance gradients, and fill them in layers in the inner cavity; One type of resin is used to fill the bottom layer region of the cavity; Another type of resin is used to fill the upper region of the cavity, and the resin in the upper region has a lower viscosity than the resin in the lower region. The bottom layer of high-viscosity resin fills the wrinkled body to provide structural support, while the upper layer of low-viscosity resin penetrates the tiny gaps to eliminate micropores, forming a performance gradient transition, thereby solving the problem of uneven stress between the shallow layer and the deep layer. S55, a small vacuum bag is laid on the repair surface and sealed and vacuumed, and a release film is placed at the junction of the repair area and the adjacent parent material. S56, after the second curing is performed, internal defect detection is performed again; Furthermore, the repair process achieves closed-environment control through vacuum extraction and debonding film setup, eliminating air bubbles and preventing the repair layer from adhering to the base material. Secondary curing ensures complete resin cross-linking. Finally, a re-inspection verifies the integrity of the repair.

[0040] Working principle: Wrinkle root cause control is achieved through a dual-pathway approach: First, a temporary interface modifier containing silane coupling agent and polyethylene glycol is sprayed before curing. Its low-temperature lubrication properties significantly reduce fiber slip resistance. Combined with the low-pressure compaction window of the first stage of two-stage curing, the surface compressed fibers in the R zone are rearranged without excessive friction, eliminating micro-wrinkles. At the same time, flow is restricted by thick breathable felt strips, and local high-pressure peaks are formed during vacuuming, forcing excess resin to be discharged directionally along a preset path, reducing the resin content, thereby solving the problem of fiber buckling instability caused by resin retention. By setting up a detection and repair process, relying on ultrasonic C-scan 3D modeling and gradient internal cavity scraping technology, after quantifying the defect morphology, a layered filling of high-viscosity resin at the bottom and low-viscosity resin at the top is adopted, combined with the interlocking repair of the micro-angle pore size gradient internal cavity, to ensure the porosity after repair, improve the interface bonding strength, and finally achieve the elimination of wrinkle defects throughout the entire cycle from molding to repair, meeting the high reliability requirements of the main load-bearing components of aerospace composite materials.

[0041] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A method for improving wrinkle defects in the R region of a rib, characterized in that, Includes the following steps: S1, Mold treatment: Based on the aluminum alloy C-type mold, acetone cleaning and anhydrous ethanol wiping are performed in sequence, and a release agent is applied to the working surface of the mold and then dried at room temperature; S2, Prepreg Laying: According to the preset number of layers and angle, the prepreg is cut into pieces using an automatic fabric cutter and laid in a clean room. During the laying process, vacuum pre-extraction is performed for more than 15 minutes after every 4 layers of prepreg are laid. S3, Encapsulation: After the prepreg is laid, a peelable fabric is laid on the surface of the prepreg and the R area is isolated. Then, a vacuum encapsulation structure is set up. S4, Curing: Transfer the mold to the effective temperature range of the autoclave, and after passing the leak test, implement a two-stage heating and pressurization strategy until curing is complete and the mold is demolded. S5, inspect for internal defects in the R area and repair defective parts; Before curing in step S4, a modifier is also applied, specifically: After the prepreg is laid up, a temporary interface modifier is evenly and in small amounts sprayed onto the R area using a low-pressure sprayer equipped with a fine-nozzle nozzle. After spraying, let it stand for 5 to 10 minutes, then proceed to step S4; The temporary interface modifier includes a silane coupling agent solution and polyethylene glycol; The temporary interface modifier is a diluted aqueous solution; In step S4, the two-stage heating and pressurization strategy is specifically as follows: Phase 1: Rapid heating and initial high-pressure compaction: Heat the workpiece to 60~80℃ and hold for 30~35 minutes, with a heating rate of 1.5~2.5℃ / min; Then, pressurize to 0.2~0.3MPa and hold for 20~25 minutes; Phase Two: Gelping and Curing After the pressure holding period is completed, increase the pressure to 0.6~0.65MPa and hold the pressure at this level for 30~40 minutes. Then, the temperature is raised to 175~180℃ and held at that temperature and pressure for 90~120 minutes; Continue until the part is completely cured.

2. The method for improving wrinkle defects in the R region of a rib according to claim 1, characterized in that: The vacuum sealing structure includes a porous isolation membrane, a non-porous isolation membrane, a breathable felt layer, and a vacuum bag; When laying the vacuum sealing structure, the porous separator, non-porous separator, breathable felt layer and vacuum bag are laid in sequence.

3. The method for improving wrinkle defects in the R region of a rib according to claim 2, characterized in that: The specific steps for laying the breathable felt layer are as follows: Multiple breathable felt strips based on the part profile are prepared and laid along the geometric profile of the prepreg blank; The breathable felt strip is placed above the non-porous isolation membrane, and the breathable felt strip is kept 10mm to 50mm away from the edge of the part, and the breathable felt strip does not contact the surface of the part.

4. The method for improving wrinkle defects in the R region of a rib according to claim 2, characterized in that: The breathable felt layer also includes thick breathable felt strips; The thick breathable felt strip is formed by stacking and pressing 2 to 3 layers of the breathable felt strip, and is set in accordance with the outline of the R area; The thick breathable felt strips are laid on the top layer of the breathable felt layer, surrounding the outline of the R area.

5. The method for improving wrinkle defects in the R region of a rib according to claim 1, characterized in that: The specific procedure for detecting internal defects in area R in step 5 is as follows: S51, visually inspect the surface quality of the R area of ​​the part, and combine it with ultrasonic C-scan to identify internal structural defects, and classify the part as qualified or unqualified. S52 performs a deep 3D scan on non-conforming parts to determine the depth, area, and 3D morphology of defects and construct a 3D data model. S53, based on the most obvious defect in the R area, cuts out an inner cavity that gradually deepens towards the center of the R area, and polishes and chemically cleans the surface of the inner cavity; S54, prepare two composite matrix resins with different performance gradients, and fill them in layers in the inner cavity; S55, a small vacuum bag is laid on the repair surface and sealed and vacuumed, and a release film is placed at the junction of the repair area and the adjacent parent material. S56, after the second curing is performed, internal defect detection is performed again.

6. The method for improving wrinkle defects in the R region of a rib according to claim 5, characterized in that: In step S53, the diameter of the inner cavity gradually decreases from the outside to the inside; The inner surface of the cavity is set with a continuous gradient at a preset micro-angle, which is 1~5°.

7. The method for improving wrinkle defects in the R region of a rib according to claim 5, characterized in that: The preparation of the composite matrix resin with two different performance gradients specifically involves: A resin is used to fill the bottom layer region of a cavity; Another type of resin is used to fill the upper region of the cavity, the resin in the upper region having a lower viscosity than the resin in the lower region.

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