A method for controlling cure distortion of a fiber reinforced resin matrix composite component

Abstract

The application belongs to the technical field of composite material forming simulation, and is a control method for curing deformation of a fiber-reinforced resin-based composite component. The method comprises the following steps: S1: establishing a curing deformation simulation analysis model of the fiber-reinforced resin-based composite component, and predicting the deformation amount and the main deformation area of the component after curing forming; S2: determining a compensation layer material; S3: determining the shape and size of the flexible compensation layer according to the deformation amount of the main deformation area; S4: placing the prepreg on the mold according to the layer design of the fiber-reinforced resin-based composite component, placing the flexible compensation layer in the main deformation area, and continuing subsequent auxiliary material laying and curing; and after curing, removing the auxiliary material and the flexible compensation layer to obtain a complete composite component.

Description

Technical Field

[0001] This invention belongs to the field of composite material molding simulation technology, and provides a method for controlling the curing deformation of fiber-reinforced resin-based composite material components. Background Technology

[0002] Fiber-reinforced resin matrix composites possess significant advantages such as high specific strength, high specific modulus, strong designability, good fatigue resistance, excellent corrosion resistance, and ease of large-area integral molding. They have been widely used in the fabrication of structural components in the aerospace field. However, the anisotropy and inhomogeneity of composite materials make their molding process difficult to control. During curing, due to the inconsistency in the thermal expansion coefficients of the resin and fibers, the chemical shrinkage of the resin, and the interaction between the component and the mold, the composite material often undergoes curing deformation after molding. This curing deformation not only affects the quality of the component but also introduces new problems for subsequent sub-assembly and final assembly.

[0003] Traditional methods for controlling composite material deformation in manufacturing processes rely on engineering experience. These methods include optimizing curing process curves and designing compensating mold surfaces. Test specimens are manufactured, and deformation is assessed and statistically analyzed using tooling, coordinate measuring machines (CMMs), or scanners. Based on this statistical analysis, the product process model is iteratively optimized. This optimization process involves process design and release, pre-setting deformation in tooling surfaces and tooling preparation, product manufacturing, and deformation statistics. It is often accompanied by long development and production cycles, high technical difficulty, and high manufacturing costs. Therefore, there is an urgent need in this field for a proactive, effective, and universal method for controlling the curing deformation of composite material components. Summary of the Invention

[0004] Purpose of the invention: A method for controlling the curing deformation of fiber-reinforced resin-based composite components is provided, thereby controlling the curing deformation of composite components and reducing the cycle and cost in the component development process.

[0005] Technical solution: A method for controlling the curing deformation of fiber-reinforced resin matrix composite components includes: S1: Establish a simulation analysis model for the curing deformation of fiber-reinforced resin matrix composite components to predict the deformation amount and main deformation areas after curing. S2: Determine the material for the compensation layer; S3: Determine the shape and size of the flexible compensation layer based on the deformation amount of the main deformation area; S4: Lay the prepreg on the mold according to the layup design of the fiber-reinforced resin matrix composite component, place the flexible compensation layer in the main deformation area, and continue to lay up the subsequent auxiliary materials and cure; after curing, remove the auxiliary materials and remove the flexible compensation layer to obtain the complete composite component.

[0006] Furthermore, S2 specifically refers to: A flexible rubber or plastic material with stable chemical properties within the curing temperature range of fiber-reinforced resin matrix composites and a higher coefficient of thermal expansion than that of fiber-reinforced resin matrix composites is selected as the compensation layer.

[0007] Furthermore, flexible rubber or plastic materials include: silicone rubber, fluororubber, and polyurethane elastomers.

[0008] Furthermore, when the curing temperature of the fiber-reinforced resin matrix composite exceeds 200°C, fluororubber is selected; when it is below 150°C, ordinary silicone rubber is selected.

[0009] Furthermore, in S3: the compensation layer is circular or elliptical in shape.

[0010] Furthermore, in S3: the size of the compensation layer covers 80% to 90% of the main deformation area of ​​the component.

[0011] Furthermore, in S3, the edges of the compensation layer are machined with a slope of 15°~30°.

[0012] Furthermore, S4 also includes: laying polytetrafluoroethylene coated cloth between the prepreg and the compensation layer.

[0013] Beneficial effects: This invention reduces the deformation of composite material components by introducing a compensation layer to generate reverse stress, resulting in significant deformation control. Compared with manufacturing molds with surface compensation, it can reduce production costs and production cycle. Detailed Implementation

[0014] This invention reduces the deformation of composite material components by introducing a flexible compensation layer at a specific location, which actively induces stress opposite to the deformation trend of the composite material component during the curing process.

[0015] By establishing a simulation analysis model for the curing deformation of composite material components, the curing deformation trend, deformation amount, and main deformation areas of the components are predicted. Flexible materials with stable chemical properties and significantly higher coefficients of thermal expansion than the resin matrix within the composite material's curing temperature range are selected, such as silicone rubber, fluororubber, and polyurethane elastomers. The thickness and shape of the flexible compensation layer are designed based on the deformation amount in the main deformation areas of the component, and the compensation layer is placed on the surface of the laid-up prepreg. During the component curing process, the compensation layer is restricted and cannot expand freely, generating compressive stress on the composite material layup. Prestress opposite to the original curing deformation direction is introduced into the component, effectively reducing component deformation.

[0016] A method for controlling the curing deformation of fiber-reinforced resin matrix composite components includes: (1) Establish a simulation analysis model for the curing deformation of fiber-reinforced resin matrix composite components to predict the deformation amount and main deformation area after the components are cured and formed.

[0017] (2) Select a flexible material with stable chemical properties and a higher coefficient of thermal expansion than the resin matrix within the curing temperature range of the fiber-reinforced resin matrix composite as the compensation layer. The flexible compensation layer expands during the curing heating of the composite material but is constrained by the mold and curing pressure, generating compressive stress on the composite material. This stress can offset some of the stress caused by the curing shrinkage or cooling of the composite material. However, the coefficient of thermal expansion of the flexible compensation layer should not be too high, otherwise it may damage the composite material. Silicone rubber, fluororubber, and polyurethane elastomers can be selected as flexible compensation layers. Select a suitable material according to the curing temperature of the fiber-reinforced resin matrix composite. When the curing temperature exceeds 200℃, fluororubber is preferred, and when it is below 150℃, ordinary silicone rubber can be selected.

[0018] (3) Based on the deformation of the main deformation area of ​​the composite component obtained in step (1), design a flexible compensation layer. In order to avoid stress concentration causing indentations on the surface of the component after curing, the compensation layer is designed to be circular or elliptical, covering 80% to 90% of the deformation area of ​​the component. The edge of the compensation layer is processed into a slope of 15° to 30° to avoid obvious steps on the surface of the component after curing.

[0019] (4) Lay the prepreg on the mold according to the layup design of the fiber-reinforced resin-based composite component. Lay polytetrafluoroethylene coated cloth on the surface of the prepreg to prevent the prepreg from sticking to the flexible compensation layer. Place the flexible compensation layer designed in step (2) in the main deformation area determined in step (1), and continue to lay and cure the subsequent auxiliary materials. After curing, remove the auxiliary materials, gently pry open and remove the flexible compensation layer by hand or with a spatula to obtain a complete composite component.

[0020] Example 1 To reduce curing deformation of L-shaped composite components, follow these steps: Step 1: Establish a simulation analysis model for the curing deformation of L-shaped composite material components.

[0021] Step 2: Simulation calculations yielded the curing deformation results of the L-shaped composite component, predicting that the springback angle of the corner area of ​​the main deformation region after demolding of the L-shaped component is approximately 1.5°.

[0022] Step 3: Select silicone rubber as the flexible compensation material based on the curing temperature of the prepreg.

[0023] Step 4: Select a 1mm thick silicone rubber sheet as a flexible compensation layer and cut it into strips of the same length as the inner corner area of ​​the L-shaped component.

[0024] Step 5: Lay the prepreg on the mold surface according to the layup design.

[0025] Step 6: Place a release liner on the surface of the laid prepreg and a flexible compensation layer in the inner corner area.

[0026] Step 7: After placing the flexible compensation layer, seal it with auxiliary materials such as felt and vacuum bags, and then place it in an autoclave for curing.

[0027] Step 8: After curing, demold and measure the springback angle of the L-shaped component. The results show that the springback angle of the L-shaped component was reduced to 0.3°, and the curing deformation control effect reached about 80%.

[0028] The above detailed embodiments are a description of the present invention. It should not be considered that the specific embodiments of the present invention are limited to these descriptions. For those skilled in the art, several simple deductions and substitutions can be made without departing from the concept of the present invention, and all of these should be considered to fall within the protection scope of the present invention.

Claims

1. A method for controlling the curing deformation of fiber-reinforced resin-based composite material components, characterized in that, include: S1: Establish a simulation analysis model for the curing deformation of fiber-reinforced resin matrix composite components to predict the deformation amount and main deformation areas after curing. S2: Determine the material for the compensation layer; S3: Determine the shape and size of the flexible compensation layer based on the deformation amount of the main deformation area; S4: Lay the prepreg on the mold according to the layup design of the fiber-reinforced resin matrix composite component, place the flexible compensation layer in the main deformation area, and continue to lay up the subsequent auxiliary materials and cure; after curing, remove the auxiliary materials and remove the flexible compensation layer to obtain the complete composite component.

2. The control method according to claim 1, characterized in that, S2, specifically: A flexible rubber or plastic material with stable chemical properties within the curing temperature range of fiber-reinforced resin matrix composites and a higher coefficient of thermal expansion than that of fiber-reinforced resin matrix composites is selected as the compensation layer.

3. The control method according to claim 2, characterized in that, Flexible rubber or plastic materials include: silicone rubber, fluororubber, and polyurethane elastomers.

4. The control method according to claim 3, characterized in that, When the curing temperature of fiber-reinforced resin matrix composites exceeds 200℃, fluororubber should be selected; when it is below 150℃, ordinary silicone rubber should be selected.

5. The control method according to claim 1, characterized in that, In S3: the compensation layer is circular or elliptical in shape.

6. The control method according to claim 1, characterized in that, In S3: The size of the compensation layer covers 80% to 90% of the main deformation area of ​​the component.

7. The control method according to claim 1, characterized in that, In S3, the edges of the compensation layer are machined with a slope of 15°~30°.

8. The control method according to claim 1, characterized in that, S4 also includes: laying polytetrafluoroethylene coated cloth between the prepreg and the compensation layer.