Method for controlling curing deformation of composite stiffened wallboard

Abstract

The invention relates to the technical field of composite material forming, in particular to a method for controlling curing deformation of a composite material stiffened wallboard, which comprises the following steps: curing and forming a rib of which the included angle between a web and an edge strip has a certain adjustment value compared with a design theoretical value; the cured and formed ribs are placed at the preset position of the skin through a rib mold, and the skin or the adhesive film is cured through heating; and after cooling and demolding, the rib mold is removed, and the finally needed composite material stiffened wall plate is obtained. The cost and period of curing deformation control can be greatly reduced.

Description

Technical Field

[0001] The present application relates to the technical field of composite material forming, and in particular to a method for controlling curing deformation of a composite material reinforced wall panel. Background Art

[0002] Resin-based composite materials have been widely used in the fields of aviation and aerospace due to their high specific stiffness, specific strength, fatigue properties, etc. However, during the manufacturing process of resin-based composite materials, residual stress is generated inside the material due to the anisotropic thermal expansion and contraction effect of the composite material itself, the exothermic effect of the chemical reaction of the matrix resin, the chemical shrinkage of the resin, and the significant difference in thermal expansion coefficient between the composite material and the mold material used for molding, which leads to deformation of the part after demolding. This has become a major concern.

[0003] Composite reinforced wall panels are a common type of main load-bearing composite material structure, which are composed of ribs and skins in L-shaped, Z-shaped, T-shaped, I-shaped or hat-shaped shapes. The molding methods of composite reinforced wall panels include co-curing, adhesive co-curing, secondary adhesive bonding, liquid molding and the like. Co-curing of cured ribs and uncured skins and secondary adhesive bonding of cured ribs and cured skins are commonly used methods to mold composite reinforced wall panels. Regardless of the molding method, how to control the curing deformation of composite reinforced wall panels is a technical problem that needs to be solved urgently by technicians in this field. Summary of the invention

[0004] In order to solve the above problems, the present application provides a method for controlling the curing deformation of a composite material reinforced wall panel, comprising:

[0005] The angle between the cured web and the flange has a certain adjustment value compared with the design theoretical value;

[0006] The solidified ribs are placed at predetermined positions of the skin through rib molds, and the skin or the adhesive film is cured by heating;

[0007] After cooling and demoulding, the rib mold is removed to obtain the final required composite reinforced wall panel.

[0008] Furthermore, the ribs whose angles between the cured and formed webs and the edge strips have a certain deviation value compared with the design theoretical value include:

[0009] The angle between the solidified web and the flange is θ+Δθ, where θ is the design theoretical value and Δθ is the adjustment value.

[0010] Furthermore, placing the solidified ribs at predetermined positions of the skin through a rib mold comprises:

[0011] The solidified ribs are fixed on a rib mold with an angle θ between the web and the flange;

[0012] Place the assembled rib mold and ribs at the predetermined position of the skin.

[0013] Furthermore, the rib is any one of L-shaped, Z-shaped, T-shaped, I-shaped or hat-shaped.

[0014] Furthermore, when the deformation direction of the composite material reinforced wall panel is close to the rib, Δθ is greater than 0.

[0015] Furthermore, when the deformation direction of the composite material reinforced wall panel is away from the rib, Δθ is less than 0.

[0016] Furthermore, the rib mold has sufficient rigidity to constrain the ribs when forming the composite material reinforced wall panel, and can be removed after the composite material reinforced wall panel is formed without damaging the ribs during the removal process.

[0017] Furthermore, the cured ribs are fixed to the rib mould by gluing or other methods.

[0018] Furthermore, the material of the rib mold is any one of a water-soluble ceramic core, wax that can be melted by heating, and glass fiber reinforced plastic that can be peeled off or removed by processing.

[0019] Furthermore, the skin is cured or uncured when the composite material stiffened wall panel is formed.

[0020] The above technical solution of the present application has the following advantages:

[0021] The method for controlling the curing deformation of the composite material stiffened wall panel provided by the present application is to cure and form a rib whose angle between the web and the edge strip has a certain adjustment value compared with the design theoretical value, place the cured and formed rib in a predetermined position of the skin through a rib mold, heat up and cure the skin or cure the film, remove the rib mold after cooling and demoulding, and obtain the final required composite material stiffened wall panel, the cured rib material is an elastomer, and stress is introduced inside. When the rib mold is removed, the stress introduced on the rib will be released, resulting in the overall curing deformation of the composite material stiffened wall panel being different from the curing deformation before the present method is adopted. The design adjustment value makes the stress introduced into the rib release so that the overall shape of the composite material stiffened wall panel at room temperature is close to the ideal shape of the design, and finally obtains the required component size and precision. Compared with the existing mold surface compensation method, the present application only needs to design a new mold for manufacturing the ribs, and does not need to redesign and manufacture the skin mold with large size and high requirements, which can greatly reduce the cost and cycle of curing deformation control. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 Theoretical appearance diagram of composite reinforced wall panel provided for this application;

[0024] Figure 2 This is the warping and curing deformation diagram of the composite material reinforced wall panel in the positive direction of the Z axis provided in this application;

[0025] Figure 3 The rib with Δθ>0 and its mold assembly diagram provided in this application;

[0026] Figure 4 This is the curing deformation diagram of the composite material reinforced wall panel in the negative direction of the Z axis provided in this application;

[0027] Figure 5 The rib with Δθ<0 and its mold assembly diagram provided in this application.

[0028] Figure numerals: 1. rib mould, 2. rib. DETAILED DESCRIPTION

[0029] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0030] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, wholes, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or combinations thereof.

[0031] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0032] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways. "Multiple" means "two or more".

[0033] The present application proposes a method for controlling the curing deformation by introducing an additional stress field into the cured ribs when the cured ribs and uncured skins are co-bonded to form or the cured ribs and skins are secondary bonded to form a composite material reinforced wall panel, thereby reducing the cost and cycle of curing deformation control.

[0034] The specific implementation methods of the present application are further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present application but are not intended to limit the scope of the present application.

[0035] The method for controlling the curing deformation of a composite stiffened wall panel provided in an embodiment of the present application comprises: curing and forming ribs in which the angle between the web and the edge strip has a certain adjustment value compared to the design theoretical value; placing the cured and formed ribs at a predetermined position on the skin through a rib mold, heating and curing the skin or curing the adhesive film; and removing the rib mold after cooling and demolding to obtain the final desired composite stiffened wall panel.

[0036] In some embodiments, the ribs whose angle between the cured formed web and the edge strip has a certain deviation value compared to the design theoretical value include: ribs whose angle between the cured formed web and the edge strip is θ+Δθ, θ is the design theoretical value, and Δθ is the adjustment value.

[0037] In some embodiments, placing the solidified ribs at predetermined positions on the skin through rib molds includes: fixing the solidified ribs on a rib mold with an angle θ between the web and the edge strip; and placing the combined rib mold and ribs at predetermined positions on the skin.

[0038] In some embodiments, the rib is any one of L-shaped, Z-shaped, T-shaped, I-shaped or hat-shaped.

[0039] In some embodiments, when the deformation direction of the composite material reinforced wall panel is close to the rib, Δθ is greater than 0.

[0040] In some embodiments, when the deformation direction of the composite material reinforced wall panel is away from the rib, Δθ is less than 0.

[0041] In some embodiments, the rib mold has sufficient rigidity to constrain the ribs when forming the composite material reinforced wall panel, and can be removed after the composite material reinforced wall panel is formed without damaging the ribs during the removal process.

[0042] In some embodiments, the cured ribs are fixed to the rib mold by gluing or other methods.

[0043] In some embodiments, the material of the rib mold is any one of a water-soluble ceramic core, wax that can be melted by heating, and glass fiber reinforced plastic that can be peeled off or removed by processing.

[0044] In some embodiments, the skin is cured or uncured when forming the composite stiffened panel.

[0045] In the past, research on the curing deformation of composite materials caused by molding mainly focused on simple structures such as L-shaped and U-shaped structures. The deformation of the integral composite reinforced wall panel structure has not received widespread attention and in-depth research. Only some studies have focused on the influence of the laminated structure of the component on the structural deformation. For the method of controlling the curing deformation, the main consideration is to compensate for the deformation of the molding die surface, and finally obtain the required component dimensions and accuracy. The method of mold surface compensation is to design the mold surface based on numerical simulation or empirical design to compensate for the thermoelastic deformation of the component during the curing cooling process and the deformation of the component caused by the thermal expansion deformation of the mold during the curing process. This method requires reprocessing of the existing molding mold and even remanufacturing of the entire set of molding molds for the rib mold and the skin mold. In particular, the skin mold is generally large in size and has high requirements, resulting in high cost of curing deformation control and long iterative optimization cycle.

[0046] In an embodiment of the present application, when forming a composite material reinforced wall panel, an additional stress field is introduced into the solidified ribs to control the curing deformation, including the following steps: curing and forming the ribs with an angle of θ+Δθ between the web and the edge; fixing the solidified ribs on a rib mold with an angle of θ between the web and the edge; placing the combined rib mold and ribs at a predetermined position on the skin, heating and curing the skin or curing the adhesive film; removing the rib mold after cooling and demolding to obtain the final required composite material reinforced wall panel.

[0047] The ribs are of L-type, Z-type, T-type, I-type or hat-type, etc., including webs and flanges combined with the skin; θ is the theoretical design value of the angle between the rib web and flange; Δθ is the adjustment value of the angle, which can be positive or negative depending on the required deformation adjustment direction, and the value of Δθ can be determined by numerical simulation or experience; Δθ can be 0, and it is not necessary to adjust every long stringer; the rib mold has sufficient rigidity to constrain the ribs when forming the composite reinforced wall panels; the method of fixing the cured ribs on the rib mold can use film bonding or other methods such as adhesives and mechanical connections; the rib mold can be removed after the composite reinforced wall panels are formed and the removal process will not damage the ribs; the rib mold material can be a water-soluble ceramic core, wax that can be melted by heating, fiberglass that can be stripped or processed and removed, etc.; the skin can be cured or uncured when forming the composite reinforced wall panels.

[0048] The ribs with an angle of θ+Δθ between the solidified web and the edge strip are fixed on a rib mold with an angle of θ between the web and the edge strip. At this time, the solidified rib material is an elastomer and stress is introduced inside. When the rib mold is removed, the stress introduced on the rib will be released, resulting in the overall curing deformation of the composite stiffened wall panel being different from the curing deformation before the method is adopted. The design of Δθ allows the stress introduced into the rib to be released, resulting in the overall shape of the composite stiffened wall panel at room temperature being close to the ideal shape of the design, and finally obtaining the required component dimensions and accuracy. Compared with the existing mold surface compensation method, the present application only needs to design a new mold for manufacturing the ribs, and does not need to redesign and manufacture a large-sized and high-requirement skin mold, which can greatly reduce the cost and cycle of curing deformation control. In addition, when the solidified ribs are combined with the uncured skin, the skin will not be crushed because the ribs are fixed on the rib mold.

[0049] The following is an explanation through specific embodiments.

[0050] Example 1

[0051] Figure 1 The composite stiffened wall panel shown has a flat skin profile, and the theoretical design value θ of the angle between the rib web and the edge strip is 90°. Figure 1 The curing deformation of the composite reinforced wall panel after forming is shown in Figure 2 As shown in the figure, the warping is in the positive direction of the Z axis. The angle between the solidified web and the edge strip is 90°+2°, as shown in the figure. Figure 3 As shown in the figure, the five cured ribs are bonded between the web and the flange with adhesive film. Figure 3On the rib mold with a middle angle of 90°, stress is introduced on the rib after the film is cured. The material of the rib mold is a water-soluble ceramic core. The assembled rib mold and ribs are placed at the predetermined position of the skin, the uncured skin is cured by heating, and the rib mold is dissolved and removed by water after cooling and demoulding to obtain the final required composite reinforced wall panel.

[0052] Example 2

[0053] Figure 1 The composite stiffened wall panel shown has a flat skin profile, and the theoretical design value θ of the angle between the rib web and the edge strip is 90°. Figure 1 The curing deformation of the composite reinforced wall panel after forming is shown in Figure 4 As shown in the figure, the warping is in the negative direction of the Z axis. The angle between the web and the edge of the rib in the middle of the solidification molding is 90°-5°, as shown in the figure. Figure 5 As shown in FIG. 1 , the other four ribs are still formed so that the angle between the web and the flange is 90°. The cured ribs are bonded between the web and the flange with adhesive film. Figure 5 On the rib mold with a middle angle of 90°, stress is introduced on the rib after the film is cured. The material of the rib mold is glass fiber reinforced plastic. The assembled rib mold and rib are placed at the predetermined position of the skin, the uncured skin is cured by heating, and the rib mold is carefully removed by machining after cooling and demoulding to obtain the final required composite material reinforced wall panel.

[0054] It should be clear that the various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. The present application is not limited to the specific structures described above and shown in the figures. In addition, for the sake of simplicity, detailed descriptions of known methods and technologies are omitted here.

[0055] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A method for controlling curing deformation of a composite material reinforced wall panel, characterized in that: include: The angle between the cured web and the flange has a certain adjustment value compared with the design theoretical value; The solidified ribs are placed at predetermined positions of the skin through rib molds, and the skin or the adhesive film is cured by heating; After cooling and demoulding, the rib mold is removed to obtain the final required composite reinforced wall panel.

2. The method for controlling curing deformation of a composite material reinforced wall panel according to claim 1, characterized in that: The ribs whose angle between the cured and formed web and the edge strip has a certain deviation value compared with the design theoretical value include: The angle between the solidified web and the flange is θ+Δθ, where θ is the design theoretical value and Δθ is the adjustment value.

3. The method for controlling curing deformation of a composite material reinforced wall panel according to claim 2, characterized in that: Placing the solidified ribs at predetermined positions of the skin through rib molds includes: The solidified ribs are fixed on a rib mold with an angle θ between the web and the flange; Place the assembled rib mold and ribs at the predetermined position of the skin.

4. The method for controlling curing deformation of a composite material reinforced wall panel according to claim 1, characterized in that: The ribs are any one of L-shaped, Z-shaped, T-shaped, I-shaped or hat-shaped.

5. The method for controlling curing deformation of a composite material reinforced wall panel according to claim 2, characterized in that: When the deformation direction of the composite reinforced wall panel is close to the rib, Δθ is greater than 0.

6. The method for controlling curing deformation of a composite material reinforced wall panel according to claim 2, characterized in that: When the deformation direction of the composite reinforced wall panel is away from the rib, Δθ is less than 0.

7. The method for controlling curing deformation of a composite material reinforced wall panel according to claim 1, characterized in that: The rib mould has sufficient rigidity to constrain the ribs when forming the composite material reinforced wall panel, and can be removed after the composite material reinforced wall panel is formed without damaging the ribs during the removal process.

8. The method for controlling curing deformation of a composite material reinforced wall panel according to claim 3, characterized in that: The solidified ribs are fixed on the rib mould by gluing or other methods.

9. The method for controlling curing deformation of a composite material reinforced wall panel according to claim 1, characterized in that: The material of the rib mold is any one of a water-soluble ceramic core, wax that can be melted by heating, and glass fiber reinforced plastic that can be stripped or removed by processing.

10. The method for controlling curing deformation of a composite material reinforced wall panel according to claim 1, characterized in that: The skin is cured or uncured when the composite stiffened panel is formed.

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