A molding method for a thick, low-density sandwich composite material structure

Abstract

This invention relates to the field of composite material molding technology, and in particular to a molding method for a thick, low-density sandwich composite material structure, comprising the following steps: S1: Using a panel mold, titanium alloy embedded parts and panel lay-up are integrally cured to form a sandwich panel, the sandwich panel including an upper panel and a lower panel respectively manufactured; the panel mold includes a lower base plate and an upper pressure plate, the lower base plate and the upper pressure plate are connected by fastening screws and positioning pins; S2: Using a curing mold, honeycomb core and titanium alloy end parts are integrally cured to form a honeycomb assembly; the curing mold includes a lower fixing plate, an upper fixing plate and a mandrel; S3: The manufactured honeycomb assembly is connected between the manufactured upper panel and lower panel to form a sandwich composite material structure. In this invention, the sandwich panel and honeycomb core are molded separately, resulting in a high molding rate, and the titanium alloy embedded parts can improve the overall uniformity of stress distribution of the structure.

Description

Technical Field

[0001] This invention relates to the field of composite material molding technology, and in particular to a molding method for a thick, low-density sandwich composite material structure. Background Technology

[0002] Composite material products possess advantages such as light weight, high strength, corrosion resistance, acid and alkali resistance, aging resistance, and strong environmental adaptability, and have been widely used in aerospace, rail transportation, shipbuilding, and other fields. High-quality composite sandwich structures are the foundation of high-performance products and a crucial guarantee for the realization of advanced design concepts and technologies, playing a vital role in the development of modern science and technology. The molding process of the sandwich structure in composite material products is particularly important.

[0003] Composite material sandwich structures have advantages such as high specific stiffness, resistance to instability, strong thermal insulation, and high load-bearing capacity. However, composite material sandwich structures, especially thick, low-density sandwich structures, still have the following problems in terms of molding structure and process:

[0004] 1. Existing composite sandwich structures with honeycomb cores are prone to problems such as wrinkling, collapse, and instability during the molding process.

[0005] 2. During the co-curing process of existing composite sandwich structures, wrinkles and bending are prone to occur in the upper and lower panel structures.

[0006] Therefore, how to overcome the above-mentioned problems in the molding process of sandwich composite structures in the existing technology, and design a molding method for large-thickness, low-density sandwich composite structures with high molding rate and reasonable structural stress distribution is an urgent problem to be solved. Summary of the Invention

[0007] To address the aforementioned problems, this invention provides a molding method for a thick, low-density sandwich composite material structure. By molding the sandwich panel and honeycomb core separately, the molding rate can be improved, and phenomena such as wrinkling, collapse, and instability that occur during the molding process can be reduced. Furthermore, the overall structure can be reasonably stress-distributed through titanium alloy embedded parts.

[0008] To achieve the above objectives, the present invention proposes the following technical solution: a molding method for a thick, low-density sandwich composite material structure, comprising the following steps:

[0009] S1: Using a panel mold, titanium alloy embedded parts and panel layup are integrally cured and molded to form a sandwich panel, which includes an upper panel and a lower panel.

[0010] S2: The honeycomb core and titanium alloy end components are integrally cured and molded into a honeycomb assembly using a curing mold;

[0011] S3: Connect the fabricated honeycomb assembly between the fabricated upper and lower panels to form a sandwich composite material structure.

[0012] Preferably, the panel mold in S1 includes a lower base plate and an upper pressure plate located above the lower base plate. The lower base plate and the upper pressure plate are connected by fastening screws and positioning pins. The sandwich panel is formed between the lower base plate and the upper pressure plate.

[0013] Preferably, S1 includes the following sub-steps:

[0014] S11: Lay the lower release cloth and the lower fiber layer sequentially on the lower base plate;

[0015] S12: Embed titanium alloy pre-embedded parts on the lower fiber layer and connect the titanium alloy pre-embedded parts to the lower base plate using connecting screws;

[0016] S13: Lay the upper fiber layer and the upper release cloth sequentially on the lower fiber layer and the titanium alloy embedded part;

[0017] S14: Cover the upper pressure plate onto the upper release cloth, and connect the upper pressure plate and the lower base plate with positioning pins and fastening screws to form a panel processing assembly;

[0018] S15: The panel processing assembly is placed in a hot autoclave for curing and molding to obtain a sandwich panel.

[0019] Preferably, the upper panel and the lower panel are manufactured separately by S11-S15.

[0020] Preferably, the curing mold in S2 includes a lower fixed plate, an upper fixed plate, and multiple mandrels located between the upper fixed plate and the lower fixed plate, with the upper fixed plate and the lower fixed plate connected by locating pins.

[0021] Preferably, both ends of the mandrel extend to the outside of the upper and lower fixing plates, and each mandrel is provided with titanium alloy end components at both ends, which are connected to the upper and lower fixing plates by connecting screws.

[0022] Preferably, S2 includes the following sub-steps:

[0023] S21: Lay the middle release cloth on the lower fixed plate and the mandrel;

[0024] S22: Lay a central fiber layer on the central release fabric to form a honeycomb core;

[0025] S23: Cover the upper fixing plate with the lower fixing plate and connect the upper fixing plate and the lower fixing plate by the second positioning pin;

[0026] S24: Place the titanium alloy end components at both ends of the mandrel, and connect the titanium alloy end components to the upper and lower fixing plates by connecting screws to form a honeycomb core processing assembly;

[0027] S25: The honeycomb core processing assembly is placed in an autoclave for curing and molding to obtain a honeycomb assembly including a honeycomb core and titanium alloy end components.

[0028] Preferably, the upper panel and lower panel in S3 are connected to the titanium alloy end components in the honeycomb assembly via titanium alloy embedded parts.

[0029] Preferably, the mandrel has a cylindrical structure or a polygonal structure.

[0030] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0031] 1. In this invention, the sandwich panel and the honeycomb core are formed separately by the panel mold and the curing mold, which can greatly improve the forming rate. At the same time, it can avoid wrinkling, collapse and instability during the honeycomb core forming process, and can avoid wrinkling and bending of the upper and lower panels in the sandwich panel during the co-curing forming process of the sandwich structure.

[0032] 2. In this invention, the sandwich panel and the honeycomb assembly are connected by titanium alloy embedded parts, which makes the stress distribution of the overall structure reasonable. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the external structure of the sandwich composite material structure after molding, according to an embodiment of the present invention;

[0034] Figure 2 This is a schematic cross-sectional view of the sandwich composite material structure after molding, according to an embodiment of the present invention.

[0035] Figure 3 This is a schematic diagram of the structure of a panel mold provided according to an embodiment of the present invention;

[0036] Figure 4 This is a schematic diagram of a curing mold structure for manufacturing a honeycomb core according to an embodiment of the present invention.

[0037] Reference numerals: Lower panel 11a, Upper panel 11b, Honeycomb core 12, Titanium alloy embedded part 13, Upper titanium alloy embedded part 13a, Lower titanium alloy embedded part 13b, Titanium alloy end component 14, Upper titanium alloy end component 14a, Lower titanium alloy end component 14b, Connecting screw one 15, Locating pin one 16, Fastening screw 17, Upper fiber layer 18, Lower fiber layer 19, Lower base plate 20, Upper pressure plate 21, Lower fixing plate 22, Upper fixing plate 23, Mandrel 24, Connecting screw two 25, Locating pin two 26, Connecting screw three 27. Detailed Implementation

[0038] The appendix will be referenced below. Figure 1-4 Embodiments of the present invention are described below. In the following description, the same modules are denoted by the same reference numerals. Where the same reference numerals are used, their names and functions are also the same. Therefore, their detailed description will not be repeated.

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the following description is provided in conjunction with the appendix. Figure 1-4 The present invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and do not constitute a limitation thereof.

[0040] A method for molding a thick, low-density sandwich composite material structure includes the following steps:

[0041] S1: A sandwich panel is manufactured by integrally curing and molding the titanium alloy embedded part 13 and the panel layer using a panel mold. The sandwich panel includes an upper panel 11b and a lower panel 11a, which are respectively processed and shaped. Figure 3 As shown, the panel mold includes a lower base plate 20 and an upper pressure plate 21. The upper pressure plate 21 is located above the lower base plate 20. The lower base plate 20 and the upper pressure plate 21 are connected by fastening screws 17 and positioning pins 16. The sandwich panel is formed between the lower base plate 20 and the upper pressure plate 21.

[0042] S1 includes the following sub-steps:

[0043] S11: As Figure 3 As shown, a lower release cloth and a lower fiber layer 19 are laid sequentially on the lower base plate 20; the lower release cloth is laid on the lower base plate 20 first, and then the lower fiber layer 19 is laid on the lower release cloth.

[0044] S12: A titanium alloy embedded part 13 is pre-embedded on the lower fiber layer 19, and the titanium alloy embedded part 13 is connected to the lower base plate 20 by connecting screw 15.

[0045] S13: The upper fiber layer 18 and the upper release cloth are laid sequentially on the lower fiber layer 19 and the titanium alloy embedded part 13; the upper release cloth is laid on the upper fiber layer 18.

[0046] S14: Cover the upper pressure plate 21 onto the upper release cloth, and use positioning pin 16 and fastening screw 17 to connect the upper pressure plate 21 and the lower base plate 20 to form a panel processing assembly;

[0047] S15: The panel assembly is placed in an autoclave for curing and molding to obtain a sandwich panel. The upper panel 11b and the lower panel 11a are manufactured separately in S11-S15.

[0048] S2: The honeycomb core 12 and the titanium alloy end component 14 are integrally cured and molded into a honeycomb assembly using a curing mold. For example... Figure 4 As shown, the curing mold includes a lower fixed plate 22, an upper fixed plate 23, and multiple mandrels 24 located between the upper fixed plate 23 and the lower fixed plate 22. The upper fixed plate 23 and the lower fixed plate 22 are connected by positioning pins 26. The mandrels 24 are evenly arranged in groups between the upper fixed plate 23 and the lower fixed plate 22, meaning that multiple honeycomb assemblies can be formed in one process. Both ends of the mandrels 24 extend to the outside of the upper fixed plate 23 and the lower fixed plate 22. Each mandrel 24 has titanium alloy end parts 14 at both ends, which are connected to the upper fixed plate 23 and the lower fixed plate 22 by connecting screws 25. The mandrels 24 can be configured as cylindrical or polygonal structures according to actual needs.

[0049] S2 includes the following sub-steps:

[0050] S21: Lay the middle release cloth on the lower fixing plate 22 and the mandrel 24;

[0051] S22: Lay a central fiber layer on the central release fabric to form a honeycomb core 12;

[0052] S23: The upper fixing plate 23 is placed on the lower fixing plate 22 and the upper fixing plate 23 and the lower fixing plate 22 are connected by the positioning pin 26; the upper fixing plate 23 and the lower fixing plate 22 are also connected by the connecting screw 3 27 to further enhance the stability of the connection between the upper fixing plate 23 and the lower fixing plate 22 and improve the forming rate of the honeycomb assembly.

[0053] S24: Place the titanium alloy end component 14 at both ends of the mandrel 24, and connect the titanium alloy end component 14 to the upper fixing plate 23 and the lower fixing plate 22 by connecting screw 25 to form a honeycomb core processing assembly;

[0054] S25: The honeycomb core processing assembly is placed in a hot autoclave for curing and molding to obtain a honeycomb assembly including the honeycomb core 12 and the titanium alloy end component 14.

[0055] S3: The fabricated honeycomb assembly is connected between the fabricated upper panel 11b and lower panel 11a to form a sandwich composite material structure. The upper panel 11b and lower panel 11a are connected to the titanium alloy end components 14 in the honeycomb assembly through titanium alloy embedded parts 13. Figure 1 and Figure 2As shown, the honeycomb core 12 is located between the upper titanium alloy end component 14a and the lower titanium alloy end component 14b in the titanium alloy end component 14. The upper titanium alloy end component 14a is connected to the upper panel 11b through the upper titanium alloy embedded part 13a, and the lower titanium alloy end component 14b is connected to the lower panel 11a through the lower titanium alloy embedded part 13b.

[0056] It should be understood that the various forms of processes shown above can be used to reorder, add, or delete steps. For example, the steps described in this invention disclosure can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution disclosed in this invention can be achieved, and this is not limited herein.

[0057] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for molding a thick, low-density sandwich composite material structure, characterized in that, Includes the following steps: S1: The titanium alloy embedded part (13) and the panel layup are integrally cured and molded into a sandwich panel using a panel mold. The sandwich panel includes an upper panel (11b) and a lower panel (11a). S2: The honeycomb core (12) and the titanium alloy end component (14) are integrally cured into a honeycomb assembly by using a curing mold; the curing mold includes a lower fixing plate (22), an upper fixing plate (23) and multiple mandrels (24) located between the upper fixing plate (23) and the lower fixing plate (22), and the upper fixing plate (23) and the lower fixing plate (22) are connected by positioning pins (26); S3: Connect the fabricated honeycomb assembly between the fabricated upper panel (11b) and lower panel (11a) to form a sandwich composite material structure; the upper panel (11b) and lower panel (11a) are connected to the titanium alloy end component (14) in the honeycomb assembly through the titanium alloy embedded part (13).

2. The molding method for a thick, low-density sandwich composite material structure according to claim 1, characterized in that, The panel mold in S1 includes a lower base plate (20) and an upper pressure plate (21) located above the lower base plate (20). The lower base plate (20) and the upper pressure plate (21) are connected by fastening screws (17) and positioning pins (16). The sandwich panel is formed between the lower base plate (20) and the upper pressure plate (21).

3. The molding method for a thick, low-density sandwich composite material structure according to claim 2, characterized in that, S1 includes the following sub-steps: S11: Lay the lower release cloth and the lower fiber layer (19) on the lower base plate (20) in sequence. S12: A titanium alloy embedded part (13) is pre-embedded on the lower fiber layer (19), and the titanium alloy embedded part (13) is connected to the lower base plate (20) by connecting screw one (15); S13: Lay the upper fiber layer (18) and the upper release cloth sequentially on the lower fiber layer (19) and the titanium alloy embedded part (13); S14: Cover the upper pressure plate (21) onto the upper release cloth, and use positioning pin (16) and fastening screw (17) to connect the upper pressure plate (21) and the lower base plate (20) to form a panel processing assembly; S15: The panel processing assembly is placed in a hot autoclave for curing and molding to obtain a sandwich panel.

4. The molding method for a thick, low-density sandwich composite material structure according to claim 3, characterized in that, The upper panel (11b) and the lower panel (11a) are respectively manufactured by S11-S15.

5. The molding method for a thick, low-density sandwich composite material structure according to claim 1, characterized in that, The two ends of the mandrel (24) extend to the outside of the upper fixing plate (23) and the lower fixing plate (22). Each mandrel (24) has a titanium alloy end component (14) on both ends, and the titanium alloy end component (14) is connected to the upper fixing plate (23) and the lower fixing plate (22) by connecting screws (25).

6. The molding method for a thick, low-density sandwich composite material structure according to claim 5, characterized in that, S2 includes the following sub-steps: S21: Lay the middle release cloth on the lower fixing plate (22) and the mandrel (24); S22: Lay a middle fiber layer on the middle release fabric to form a honeycomb core (12). S23: Cover the upper fixing plate (23) onto the lower fixing plate (22) and connect the upper fixing plate (23) and the lower fixing plate (22) through the second positioning pin (26); S24: Place the titanium alloy end component (14) at both ends of the mandrel (24), and connect the titanium alloy end component (14) to the upper fixing plate (23) and the lower fixing plate (22) by connecting screw two (25) to form a honeycomb core processing assembly; S25: The honeycomb core processing assembly is placed in a hot autoclave for curing and molding to obtain a honeycomb assembly including a honeycomb core (12) and a titanium alloy end component (14).

7. The molding method for a thick, low-density sandwich composite material structure according to claim 1, characterized in that, The mandrel (24) is a cylindrical structure or a polygonal structure.

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