Method for inhibiting curing deformation of composite stringer stiffened wallboard

Abstract

The invention belongs to the technical field of composite manufacturing and curing deformation control, and discloses a method for inhibiting curing deformation of a composite stringer stiffened wallboard, which is characterized in that the interface interaction behavior of a mold and a composite part is adjusted and controlled through the thermal expansion coefficient design of a forming mold, so that the curing deformation control of the stringer stiffened wallboard is realized. The technical problems of out-of-tolerance appearance, prestress assembly and the like caused by solidification deformation of the stringer stiffened wall plate are solved. The method has a relatively obvious curing deformation inhibition effect on a low-rigidity wall plate with relatively thin thickness.

Description

Technical Field

[0001] The invention belongs to the technical field of composite material manufacturing and curing deformation control, and specifically relates to a process method for suppressing the curing deformation of composite material long-string reinforced wall panels by means of interaction between a mold and a composite material. Background Art

[0002] Composite panels are core components of aircraft wings, fuselages, tails, etc., and their manufacturing quality represents the highest level of my country's aviation equipment. Panels often use T-shaped, hat-shaped or J-shaped long spars to increase bending stiffness, becoming long-spandrel reinforced panels. Due to the asymmetric panel structure, mismatch of fiber resin properties, resin curing shrinkage, thermal expansion and contraction, etc., the long-spandrel reinforced panels using the autoclave molding process usually show a concave deformation in the transverse direction of the skin and a convex deformation in the longitudinal direction of the spars, which seriously affects the appearance accuracy and assembly of the product.

[0003] The control methods of composite material curing deformation usually include optimization of curing process parameters, use of materials with thermal expansion coefficients close to those of composite materials to make molding molds, mold surface compensation, molding process optimization, etc. The existing methods have obvious effects on thin-walled structures with simple structures and linear curing deformation characteristics, but the control effect on nonlinear curing deformation of long-stringer reinforced wall panels is limited, and the actual implementation is not good.

[0004] Therefore, it is necessary to propose a process method to inhibit the solidification deformation of long-string reinforced wall panels to achieve high-quality manufacturing of wall panel structures. Summary of the invention

[0005] The present invention is intended to solve the technical problems of shape tolerance and prestressed assembly caused by the curing deformation of long-beam reinforced wall panels, and proposes a method for suppressing the curing deformation of long-beam reinforced wall panels of composite materials. The thermal expansion coefficient of the forming mold is designed to regulate the interface interaction behavior between the mold and the composite material parts, thereby achieving curing deformation control of the long-beam reinforced wall panels.

[0006] In order to achieve the above invention objectives, the technical solutions adopted in this application are as follows:

[0007] A method for suppressing curing deformation of a composite material long-string reinforced wall panel comprises the following steps:

[0008] Step 1: For the long-beam reinforced wall panel to be manufactured, determine its curing deformation form through typical part trial production or finite element simulation method;

[0009] Step 2: Select a prepreg system suitable for the molding die, and design the layup form of the composite material on the molding die according to the curing deformation form of the long-string reinforced wall panel obtained in step 1 and in accordance with the principle of symmetry;

[0010] Step 3: Prepare a molding mold for the long-beam reinforced wall panel in step 1;

[0011] Step 4: Lay and cure the prepreg material and the plying sequence in step 2 on the surface of the molding die prepared in step 3 to obtain a composite material template fixed on the surface of the molding die;

[0012] Step 5: Process the composite material template in step 4 according to the profile geometric parameters of the film-attaching surface of the long-beam reinforced wall panel in step 1, so that its surface roughness is ≤ Ra1.6, and obtain a long-beam reinforced wall panel forming mold with the composite material template;

[0013] Step 6: Apply a release agent or affix a release cloth to the working area of ​​the long-string reinforced wall panel forming mold with the composite profile obtained in step 5, and complete the manufacturing of the long-string reinforced wall panel according to the manufacturing process.

[0014] As a further solution of the present invention: in step 2, the working temperature of the selected prepreg system should be higher than the curing temperature of the long stringer reinforced wall panel by more than 10 degrees.

[0015] As a further solution of the present invention: in step 2, the molding die ply design should be mainly based on unidirectional prepreg and supplemented with fabric prepreg, wherein the fabric prepreg is in principle only arranged in the last layer of the ply to prevent wire splitting damage during processing.

[0016] As a further solution of the present invention: in step 2, the principle of ply design according to the curing deformation form of the long-string reinforced wall panel is as follows: the curing deformation form of the long-string reinforced wall panel is observed from both the horizontal and longitudinal directions, and for the concave deformation toward the forming mold, the proportion of the unidirectional prepreg plies perpendicular to the observation surface is increased; for the convex deformation away from the forming mold, the proportion of the unidirectional prepreg plies perpendicular to the observation surface is reduced.

[0017] As a further solution of the present invention: in step 2, the designed total thickness of the ply should not be less than 2 mm.

[0018] As a further solution of the present invention: in step 3, it is necessary to polish and remove stains, residual release agent and other debris on the surface of the molding die.

[0019] As a further solution of the present invention: in step 4, the composite material plate fixed to the surface of the molding die should be cured according to the curing parameters recommended by the supplier of the prepreg system selected in step 2.

[0020] As a further solution of the present invention: in step 4, the composite material template fixed to the surface of the forming mold can be cured and formed on the metal forming mold template of the part, and can also be installed on the metal frame after forming.

[0021] As a further solution of the present invention: in step 5, the net dimension lines and laying lines of the parts are printed on the surface of the composite material template.

[0022] As a further solution of the present invention: in step 5, the length and width of the composite material template should take into account the space required for the laying line, bag making area and tooling accessories.

[0023] Compared with the prior art, the beneficial effects of this application are:

[0024] 1. The present invention combines the curing deformation characteristics of the long-string reinforced wall panels, gives full play to the designability advantages of composite materials, controls the curing deformation of the composite material long-string reinforced wall panels by regulating the thermal expansion coefficient of the forming mold and relying on the interaction of the mold with the composite material parts, thereby realizing high-quality manufacturing of wall panel parts.

[0025] 2. The present invention has a more obvious curing deformation inhibition effect on thin and weak rigidity wall panels.

[0026] The present application is further described below in conjunction with the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention.

[0028] In the attached picture:

[0029] Figure 1 This is a schematic diagram of the structure of the long-beam reinforced wall panel required by the present invention;

[0030] Figure 2 It is a schematic diagram of the curing deformation of the long-beam reinforced wall panel of the present invention;

[0031] Figure 3 It is a schematic diagram of a forming mold of a long-string reinforced wall panel with a composite material template according to the present invention.

[0032] Explanation of the reference numerals in the figures: long stringer 11, wall panel 10, long stringer reinforced wall panel 20, concave deformation 21, convex deformation 22, forming mold 30, composite material template 31. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0034] A method for inhibiting curing deformation of a composite material long-string reinforced wall panel, the method is applicable to a thermosetting resin-based composite material autoclave molding process, and comprises the following steps:

[0035] Step 1: For the long-beam reinforced wall panel to be manufactured, determine its curing deformation form through typical part trial production or finite element simulation method.

[0036] Step 2: Select a prepreg system suitable for the forming mold. According to the curing deformation form of the long-beam reinforced wall panel obtained in step 1, follow the principle of symmetry to design the layup form of the composite material on the forming mold; the working temperature of the selected prepreg system should be more than 10 degrees higher than the curing temperature of the long-beam reinforced wall panel. The layup design of the forming mold should be mainly based on unidirectional prepreg and supplemented by fabric prepreg. In principle, the fabric prepreg is only placed in the last layer of the layup to prevent damage such as splitting during processing. The designed total thickness of the layup should not be less than 2mm.

[0037] The principle of ply design according to the curing deformation form of the long-string reinforced wall panel is as follows: observe the curing deformation form of the long-string reinforced wall panel from both the horizontal and longitudinal directions. For the concave deformation toward the forming mold, increase the proportion of unidirectional prepreg plies perpendicular to the observation surface; for the convex deformation away from the forming mold, reduce the proportion of unidirectional prepreg plies perpendicular to the observation surface.

[0038] Step 3: Prepare the molding mold for the long-beam reinforced wall panel in step 1; polish and remove stains, residual release agent and other debris on the surface of the molding mold.

[0039] Step 4: Lay and cure the prepreg material and the plying sequence in step 2 on the surface of the molding die prepared in step 3 to obtain a composite material plate fixed on the surface of the molding die; the composite material plate fixed on the surface of the molding die should be cured according to the curing parameters recommended by the supplier of the prepreg system selected in step 2. The composite material plate fixed on the surface of the molding die can be cured and formed on the metal molding die plate of the part, or it can be installed on a metal frame after forming.

[0040] Step 5: Process the composite template in step 4 according to the geometric parameters of the film-pasting surface of the long-beam reinforced wall panel in step 1, so that its surface roughness is ≤Ra1.6, and print the net dimension line and laying line of the part to obtain a long-beam reinforced wall panel forming mold with a composite template; the length and width of the composite template should take into account the space required for the laying line, bag making area and tooling accessories.

[0041] Step 6: Apply a release agent or affix a release cloth to the working area of ​​the long-string reinforced wall panel forming mold with the composite profile obtained in step 5, and complete the manufacturing of the long-string reinforced wall panel according to the manufacturing process.

[0042] Figure 1-3 It is a schematic diagram for explaining one embodiment of the present invention.

[0043] A method for inhibiting the curing deformation of a composite material long-string reinforced wall panel, the method is applicable to a thermosetting resin-based composite material autoclave molding process, and the method for inhibiting the curing deformation of the long-string reinforced wall panel specifically comprises the following steps:

[0044] Step 1: For the T-shaped long girder 11 reinforced wall panel 10 to be manufactured, the molding die is located below the wall panel and away from the long girder. The long girder reinforced wall panel 20 after curing and deformation is obtained through trial production of the wall panel. It can be found that the deformation form of the wall panel is: the horizontal direction is a concave deformation 21 towards the molding die, and the vertical direction is a convex deformation 22 away from the die.

[0045] Step 2: Select a domestic carbon fiber unidirectional prepreg and glass fiber fabric prepreg with a single layer curing thickness of 0.14mm and 0.12mm respectively for ply design. Define the long stringer direction as the 0° direction, and the direction perpendicular to the long stringer as the 90° direction. Combined with the deformation form of the long stringer reinforced wall panel obtained in step 1, the designed ply is [O 14 / (±45)].

[0046] Step 3: Prepare the molding mold 30 of the long-beam reinforced wall panel, and polish and remove surface stains, residual mold release agent and other debris.

[0047] Step 4: According to the prepreg material and ply sequence selected in step 2 [O 14 / (±45)] is laid on the surface of the prepared molding die 30 and cured to obtain a composite material template 31 fixed on the surface of the molding die.

[0048] Step 5: According to the geometric parameters of the film-pasting surface of the long-beam reinforced wall panel in step 1, the composite material template in step 4 is machined to make its surface roughness ≤Ra 1.6, and the net dimension line and laying line of the part are printed to obtain the following: Figure 3 The long stringer stiffened wall panel forming mold with composite profile is shown.

[0049] Step 6: Apply a release agent to the working area of ​​the long-string reinforced wall panel forming mold with the composite template obtained in step 5, and complete the manufacturing of the long-string reinforced wall panel according to the manufacturing process flow.

[0050] This method combines the anisotropic curing deformation characteristics of long-string reinforced wall panels, gives full play to the designability of composite materials, and controls the curing deformation by adjusting the thermal expansion behavior of the long-string reinforced wall panel forming mold. It has low manufacturing cost and has a more obvious curing deformation inhibition effect on thin and weak rigidity wall panels, and has strong engineering application value.

[0051] So far, the purpose of the present invention has been achieved.

[0052] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for suppressing the curing deformation of a composite material long-string reinforced wall panel, characterized in that: The steps include: Step 1: For the long-beam reinforced wall panel to be manufactured, determine its curing deformation form through typical part trial production or finite element simulation method; Step 2: Select a prepreg system suitable for the molding die, and design the layup form of the composite material on the molding die according to the curing deformation form of the long-string reinforced wall panel obtained in step 1 and in accordance with the principle of symmetry; Step 3: Prepare a molding mold for the long-beam reinforced wall panel in step 1; Step 4: Lay and cure the prepreg material and the plying sequence in step 2 on the surface of the molding die prepared in step 3 to obtain a composite material template fixed on the surface of the molding die; Step 5: Process the composite material template in step 4 according to the profile geometric parameters of the film-attaching surface of the long-beam reinforced wall panel in step 1, so that its surface roughness is ≤ Ra1.6, and obtain a long-beam reinforced wall panel forming mold with the composite material template; Step 6: Apply a release agent or affix a release cloth to the working area of ​​the long-string reinforced wall panel forming mold with the composite profile obtained in step 5, and complete the manufacturing of the long-string reinforced wall panel according to the manufacturing process.

2. A method for suppressing curing deformation of composite material long-string reinforced wall panels according to claim 1, characterized in that: In step 2, the working temperature of the selected prepreg system should be more than 10 degrees higher than the curing temperature of the long stringer reinforced wall panel.

3. The method for suppressing the curing deformation of a composite material long-string reinforced wall panel according to claim 1, characterized in that: In step 2, the molding die ply design should be based on unidirectional prepregs and supplemented with fabric prepregs. In principle, fabric prepregs are only placed in the last layer of the ply to prevent wire splitting damage during processing.

4. A method for suppressing curing deformation of a composite material long-string reinforced wall panel according to claim 3, characterized in that: In step 2, the principle of ply design based on the curing deformation form of the long-string reinforced wall panel is as follows: observe the curing deformation form of the long-string reinforced wall panel from both the horizontal and longitudinal directions, and for the concave deformation toward the forming mold direction, increase the proportion of unidirectional prepreg ply perpendicular to the observation surface; For the convex deformation away from the forming mold, the proportion of unidirectional prepreg plies perpendicular to the observation surface is reduced.

5. A method for suppressing curing deformation of composite material long-string reinforced wall panels according to claim 4, characterized in that: In step 2, the designed total ply thickness should not be less than 2 mm.

6. The method for suppressing the curing deformation of a composite material long-string reinforced wall panel according to claim 1, characterized in that: In step 3, the surface of the mold needs to be polished to remove stains, residual release agent and other debris.

7. The method for suppressing the curing deformation of a composite material long-string reinforced wall panel according to claim 3, characterized in that: In step 4, the composite material template fixed to the surface of the molding mold should be cured according to the curing parameters recommended by the supplier of the prepreg system selected in step 2.

8. A method for suppressing curing deformation of a composite material long-string reinforced wall panel according to claim 1 or 7, characterized in that: In step 4, the composite material template fixed to the surface of the forming mold can be cured and formed on the metal forming mold template of the part, or it can be installed on the metal frame after forming.

9. The method for suppressing the curing deformation of a composite material long-string reinforced wall panel according to claim 1, characterized in that: In step 5, the net dimension lines and laying lines of the parts are printed on the surface of the composite material template.

10. A method for suppressing curing deformation of composite material long-string reinforced wall panels according to claim 9, characterized in that: In step 5, the length and width of the composite material template should take into account the space required for the laying line, bag making area and tooling accessories.

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