Thin-wall composite material plate structure internally provided with hollow runner

Abstract

The utility model relates to the technical field of composite material preparation, in particular to a thin-wall composite material plate structure with a hollow runner inside, which is formed by co-curing an upper composite material panel, a lower composite material panel and a runner layer clamped between the upper composite material panel and the lower composite material panel through resin, the problems that in a traditional technology, a flow channel is prone to being blocked, and interface bonding is weak are solved, and the heat pipe has the advantages of being good in structural integrity, excellent in sealing performance, light in weight and high in strength and is particularly suitable for heat management structural parts in the fields of aerospace, new energy automobiles, high-end equipment and the like.

Description

Technical Field

[0001] This utility model relates to the field of composite material preparation technology, specifically to a thin-walled composite material plate structure with internal hollow flow channels. Background Technology

[0002] In aerospace, new energy vehicles, and high-end equipment, key components that combine structural load-bearing and thermal management functions have a wide range of applications. For example, wing leading-edge structures, battery pack heat sinks, and lightweight liquid-cooled plates are typically designed with complex internal flow channels for the flow of coolant or heat transfer media, while simultaneously meeting comprehensive performance requirements such as lightweight, high strength, and corrosion resistance. These internal flow channels are often relatively small in height and large in width, and densely arranged within the plate, posing a significant challenge to composite material manufacturing processes. Furthermore, the flow channel structure must withstand high internal pressure and adapt to harsh environmental conditions such as high temperatures, placing higher demands on the overall performance and environmental reliability of the structure. Traditional methods for manufacturing such composite material structures with flow channels mainly include the composite secondary processing method, the built-in removable core material method, and the built-in detachable core material method. The composite secondary processing method involves separately manufacturing the upper panel, lower panel, and flow channel plate of the composite material, and then assembling them by adhesive bonding or mechanical connection. However, this method suffers from problems such as multiple interfaces, poor connection reliability, poor sealing, cumbersome processes, and low production efficiency. Additionally, adhesives may introduce aging risks and additional weight. The built-in removable core material method involves pre-inserting a soluble or fusible core mold into the composite material layup, which is then removed after molding to form flow channels. However, this method is complex, and incomplete core material removal can clog the flow channels, and it is also environmentally unfriendly. The built-in removable core material method involves pre-inserting a removable core mold into the composite material layup, using autoclave or compression molding processes, and finally removing the core material. However, due to the laminated layup, the adhesive interface between the flow channels and the upper and lower panels becomes a weak point, with low internal pressure tolerance, making it prone to delamination, which in turn leads to flow channel damage and fluid leakage. Furthermore, during molding, the inability to provide lateral pressure to the flow channel walls results in insufficient compaction of the sides, easily leading to defects such as porosity, which also affects the quality of the flow channel walls. VARI (Vacuum-Assisted Resin Infusion Molding) technology, as a low-cost composite material molding technology, has been widely used in the manufacture of large and complex structural components. However, how to use the VARI process to integrally mold thin-walled composite material plate structures containing continuous, sealed, high-performance hollow flow channels in a single operation remains a technical challenge in this field. The main challenge lies in ensuring that the resin flows and impregnates fully in the preform with a complex internal structure, while ensuring that the flow channel does not deform or collapse during the molding process, and can form a solid integral interface with the composite material panel. Utility Model Content

[0003] This invention provides a thin-walled composite material plate structure with internal hollow flow channels to solve the problems of weak interfacial bonding, easy clogging of flow channels, and complex manufacturing process in existing composite material structures with internal flow channels.

[0004] The present invention discloses a thin-walled composite material plate structure with an internal hollow flow channel, which adopts the following technical solution:

[0005] A thin-walled composite material plate structure with internal hollow flow channels, comprising an upper composite material panel, a flow channel layer, and a lower composite material panel;

[0006] The upper composite material panel is spaced above the lower composite material panel; both the upper composite material panel and the lower composite material panel are boards formed by fiber and resin composite molding.

[0007] The flow channel layer includes a continuous flexible braided sleeve and a filler. The flexible braided sleeve forms a hollow flow channel for fluid flow. At least one flexible braided sleeve is provided, and it is disposed between the upper composite material panel and the lower composite material panel. When multiple flexible braided sleeves are provided, they are arranged parallel to each other and spaced apart between the upper composite material panel and the lower composite material panel along a direction perpendicular to the thickness of the upper composite material panel. The filler fills the positions between the upper composite material panel and the lower composite material panel where no flexible braided sleeve is provided. The upper composite material panel, the flow channel layer, and the lower composite material panel are integrally formed.

[0008] Furthermore, the flexible braided sleeve is a three-dimensional braided tube, a two-dimensional braided tube, or a knitted tube, and the material of the flexible braided sleeve is one of glass fiber, carbon fiber, aramid fiber, or basalt fiber.

[0009] Furthermore, the flexible braided sleeve is provided with a removable polytetrafluoroethylene liner inside.

[0010] Furthermore, the filler is short fibers or fabrics of glass fiber, carbon fiber, aramid fiber or basalt fiber.

[0011] Furthermore, the filler is made of the same material as the flexible braided sleeve.

[0012] Furthermore, the flexible braided sleeve is partially fixedly connected to the upper composite material panel and the lower composite material panel by stitching or soluble fiber yarn.

[0013] Furthermore, the sutures or soluble fiber yarns are spaced apart along the extension direction of the flexible braided sleeve.

[0014] Furthermore, the distance between the upper surface of the upper composite panel and the lower surface of the lower composite panel is 2 mm to 8 mm, and the thickness of both the upper and lower composite panels is 0.5 mm to 2 mm.

[0015] Furthermore, the hollow flow channel has a height of 1 mm to 4 mm and a width of 10 mm to 30 mm.

[0016] Furthermore, the resin matrix used in the composite molding is bismaleimide resin, epoxy resin, unsaturated polyester resin, or vinyl ester resin.

[0017] The beneficial effects of this utility model are as follows: This utility model provides a thin-walled composite material plate structure with an internal hollow flow channel, comprising an upper composite material panel, a flow channel layer, and a lower composite material panel. By setting a flow channel layer composed of a flexible braided sleeve and filler between the upper and lower composite material panels, and integrally molding the upper composite material panel, the flow channel layer, and the lower composite material panel, the traditional adhesive and mechanical connection are eliminated, thus eliminating the problems of delamination, delamination, and sealing failure caused by multi-layer interfaces, significantly improving the overall structural integrity, sealing performance, and connection reliability. The continuously set flexible braided sleeve can stably form a continuous and unobstructed hollow flow channel, effectively avoiding flow channel deformation, collapse, or blockage during the molding process, ensuring the dimensional accuracy and flow performance of the flow channel. With the filler filling the corresponding areas, the plate structure is uniform and stable under stress, and the whole structure has both structural load-bearing and fluid channel functions. While achieving lightweight, it also has high strength and rigidity, which can meet the needs of aerospace, new energy vehicles, and high-end equipment for lightweight, high-strength, corrosion-resistant, and thermal management components.

[0018] Furthermore, using flexible braided tubing as the core material of the flow channel, which is itself a porous medium, is conducive to the penetration and encapsulation of resin, forming a dense composite material flow channel wall. At the same time, the flexible braided tubing can effectively improve the ability of the tube wall to withstand internal pressure.

[0019] Furthermore, the flexible braided sleeve is fixed to the upper and lower composite material panels by stitching or binding, ensuring the positional stability of the flexible braided sleeve during the layup and vacuum compaction process, and avoiding deformation or performance degradation of the flexible braided sleeve due to displacement. In addition, the use of polytetrafluoroethylene as the inner lining of the flexible braided sleeve further ensures the roundness of the hollow flow channel cross-section. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this utility model 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 some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 A cross-sectional view of a thin-walled composite material plate structure with internal hollow flow channels provided for an embodiment of this utility model;

[0022] Figure 2 A cross-sectional view of the flow channel layer in a thin-walled composite material plate structure with internal hollow flow channels, provided for an embodiment of this utility model.

[0023] In the diagram: 1. Upper composite material panel; 2. Flow channel layer; 3. Lower composite material panel; 4. Flexible braided sleeve; 5. Filler; 6. Hollow flow channel. Detailed Implementation

[0024] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0025] The serial numbers assigned to components in this document, such as "first," "second," etc., are merely used to distinguish the described objects and have no sequential or technical meaning. The terms "connection" and "linkage" used in this application, unless otherwise specified, include both direct and indirect connections (linkages). In the description of this utility model, it should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0026] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0027] like Figures 1 to 2 As shown in the figure, the present invention provides a thin-walled composite material plate structure with an internal hollow flow channel, which includes an upper composite material panel 1, a flow channel layer 2 and a lower composite material panel 3.

[0028] The upper composite panel 1 is spaced above the lower composite panel 3; both the upper composite panel 1 and the lower composite panel 3 are fiber and resin composite molded plates; the flow channel layer 2 includes a continuous flexible braided sleeve 4 and a filler 5, with a hollow flow channel 6 formed inside the flexible braided sleeve 4 for fluid flow; at least one flexible braided sleeve 4 is provided, and the flexible braided sleeve 4 is provided between the upper composite panel 1 and the lower composite panel 3; when multiple flexible braided sleeves 4 are provided, the multiple flexible braided sleeves 4 are provided parallel and spaced between the upper composite panel 1 and the lower composite panel 3 along a direction perpendicular to the thickness of the upper composite panel 1; preferably, when one or more flexible braided sleeves 4 are provided, the surface of each flexible braided sleeve 4 can directly contact the lower end face of the upper composite panel 1 and the upper end face of the lower composite panel 3. The filler 5 fills the positions between the upper composite panel 1 and the lower composite panel 3 where no flexible braided sleeve 4 is provided; the upper composite panel 1, the flow channel layer 2, and the lower composite panel 3 are integrally molded.

[0029] Specifically, in the production of the thin-walled composite panel structure with internal hollow flow channels 6, the preforms of the upper composite panel 1 and the lower composite panel 3 are first made, and then the flexible braided sleeve 4 and the filler 5 are placed between the upper composite panel 1 and the lower composite panel 3. The hollow flow channels 6 inside the flexible braided sleeve 4 are filled with fluid. When the fluid flows in the hollow flow channels 6, it can absorb the heat in the upper composite panel 1 and the lower composite panel 3.

[0030] In one embodiment, the flexible braided sleeve 4 is a three-dimensional braided tube, a two-dimensional braided tube, or a knitted tube, and the material of the flexible braided sleeve 4 is one of glass fiber, carbon fiber, aramid fiber, or basalt fiber.

[0031] In one embodiment, the flexible braided sleeve 4 is provided with a removable polytetrafluoroethylene (PTFE) liner. Furthermore, during the production process, to reduce the probability of deformation of the flexible braided sleeve 4, a PTFE liner is inserted inside the flexible braided sleeve 4. Because PTFE has stable chemical and physical properties, it does not easily deform under vacuum conditions. The PTFE liner ensures that the flexible braided sleeve 4 will not collapse under vacuum conditions, thus ensuring the integrity of the flexible braided sleeve 4.

[0032] In one embodiment, the filler 5 is a short fiber or fabric of glass fiber, carbon fiber, aramid fiber or basalt fiber. The filler 5 is filled between two adjacent flexible braided sleeves 4 and between the upper composite material panel 1 and the lower composite material panel 3. The filler 5 can connect two adjacent flexible braided sleeves 4 into a whole. Similarly, the filler 5 connects the upper composite material panel 1 and the lower composite material panel 3 into a whole.

[0033] In one embodiment, the filler 5 is made of the same material as the flexible braided sleeve 4 to ensure uniform penetration during resin impregnation. For example, if the flexible braided sleeve 4 is made of glass fiber, the filler 5 is also made of glass fiber to ensure that the resin matrix used in the composite molding can uniformly impregnate the flexible braided sleeve 4 and the filler 5, thereby ensuring the stability of the hardness of the flow channel layer 2 at different locations.

[0034] In one embodiment, the flexible braided sleeve 4 is partially fixedly connected to the upper composite panel 1 and the lower composite panel 3 by stitching or soluble fiber yarn, ensuring that the flexible braided sleeve 4 does not shift relative to the upper composite panel 1 and the lower composite panel 3 during the layup and vacuum compaction process.

[0035] In one embodiment, the sutures or soluble fiber yarns are spaced apart along the length of the flexible braided sleeve 4 to reduce the probability of the flexible braided sleeve 4 shifting relative to the upper composite panel 1 and the lower composite panel 3.

[0036] In one embodiment, the distance between the upper surface of the upper composite panel 1 and the lower surface of the lower composite panel 3 is 2 mm to 8 mm, the thickness of the upper composite panel 1 and the lower composite panel 3 is 0.5 mm to 2 mm, the height of the hollow flow channel 6 is 1 mm to 4 mm, and the width is 10 mm to 30 mm. The dimensions of each component need to be adaptively adjusted according to the load-bearing capacity of the structure, the fluid flow performance of the flow channel, and the overall lightweight requirements.

[0037] In one embodiment, the resin matrix used for composite molding is bismaleimide resin, epoxy resin, unsaturated polyester resin or vinyl ester resin. In actual production, the type of resin used for composite molding needs to be selected according to the curing conditions.

[0038] In this embodiment, the specific preparation process is as follows: First, mold preparation is performed. A flat steel mold is selected as the molding tool, and after cleaning the mold surface, a release agent is evenly applied to its surface. The release agent is selected from materials with good compatibility with the resin system to avoid damage to the surface during subsequent demolding.

[0039] The preform of the lower composite material panel 3 is laid in the mold. The preform of the lower composite material panel 3 is composed of multiple layers of dry fiber fabric. In this embodiment, 8 layers of 200g T700 carbon fiber plain weave fabric are used. The selection of dry fiber fabric needs to be adjusted according to the actual application requirements. For example, one of the following can be selected: woven fabric, knitted fabric or non-cribable fabric of carbon fiber, glass fiber or aramid fiber.

[0040] After the prefabrication of the lower composite panel 3 is completed, the flow channel layer 2 is positioned and fixed. A flexible braided sleeve 4 is laid on the upper surface of the prefabrication of the lower composite panel 3. The flexible braided sleeve 4 has an outer diameter of 40mm and is made of 300g carbon fiber braided sleeve. To prevent the flexible braided sleeve 4 from collapsing under vacuum conditions, a polytetrafluoroethylene (PTFE) plate with a cross-sectional dimension of 20mm × 1.5mm is inserted inside as a liner. The PTFE liner has a smooth surface and good compressive strength, effectively maintaining the geometry of the flow channel cross-section. 200g of T700 carbon fiber plain weave fabric is filled between the flexible braided sleeves 4 to enhance the integrity and stability of the flow channel layer 2. Furthermore, dissolvable PVA yarn is used to intermittently bind and fix the flexible braided sleeve 4 to the lower composite panel 3 to ensure the positional stability of the flexible braided sleeve 4 during the layup and vacuum compaction process.

[0041] Subsequently, the prefabricated upper composite panel 1 is laid on top of the fixed flexible braided sleeve 4. The prefabricated upper composite panel 1 is also composed of 8 layers of 200-gram T700 carbon fiber plain weave fabric, and its composition is consistent with that of the lower composite panel 3. After laying the prefabricated upper composite panel 1, vacuum bag sealing is performed. The release cloth, flow guide net, and vacuum bag film are laid in sequence, and sealing strips are used to seal the vacuum bag film to the mold edge, forming a sealed cavity. The flow guide net must cover the entire structure area to ensure uniform resin flow under vacuum negative pressure.

[0042] In the vacuum leak detection and resin injection steps, the sealed cavity is evacuated to above -0.095 MPa and maintained to check for airtightness. After confirming no leakage, the mixed resin is injected into the mold cavity through the injection port under vacuum negative pressure. In this embodiment, a low-viscosity epoxy resin system is selected. Its viscosity is adjusted according to the porosity of the upper composite panel 1, the lower composite panel 3, and the flow channel layer 2, as well as the complexity of the hollow flow channel 6, to ensure that the resin can fully penetrate and encapsulate the flexible braided sleeve 4 and the filler 5, forming a dense composite material flow channel wall. The resin matrix used for composite molding can also be bismaleimide resin, unsaturated polyester resin, or vinyl ester resin. The specific selection needs to be determined according to the actual application requirements and process conditions.

[0043] After resin infusion, the curing and demolding process begins. The resin is heated at 120°C for 6 hours to ensure complete curing. After curing, the mixture is cooled and the vacuum bag system is removed. The cured part is then removed from the mold. The PTFE liner inside the runner is carefully removed, and the runner ports and product edges are trimmed to obtain the final thin-walled composite plate structure with internal hollow runners (6). Curing conditions need to be optimized based on the characteristics of the resin system to ensure complete resin curing and interfacial bonding strength.

[0044] The outer surface of the hollow flow channel 6 forms a continuous resin interface with the upper composite material panel 1 and the lower composite material panel 3, eliminating the weak connection problem of traditional adhesive bonding. The interface bonding strength is significantly improved, and the overall structure and sealing performance are optimized. The flexible braided sleeve 4 is itself a porous medium, which is conducive to resin penetration and encapsulation, forming a dense composite material flow channel wall. At the same time, the braided sleeve can effectively improve the flow channel wall's ability to withstand internal pressure. This eliminates multiple steps in traditional methods, such as core material fabrication, assembly, adhesive bonding, or removal, simplifying the process, shortening the production cycle, and significantly reducing manufacturing costs.

[0045] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A thin-walled composite panel structure having internal stringers with hollow flow channels, characterized by, Includes an upper composite panel, a flow channel layer, and a lower composite panel; The upper composite material panel is spaced above the lower composite material panel; both the upper composite material panel and the lower composite material panel are boards formed by fiber and resin composite molding. The flow channel layer includes a continuous flexible braided sleeve and a filler. The flexible braided sleeve forms a hollow flow channel for fluid flow. At least one flexible braided sleeve is provided, and it is disposed between the upper composite material panel and the lower composite material panel. When multiple flexible braided sleeves are provided, they are arranged parallel to each other and spaced apart between the upper composite material panel and the lower composite material panel along a direction perpendicular to the thickness of the upper composite material panel. The filler fills the positions between the upper composite material panel and the lower composite material panel where no flexible braided sleeve is provided. The upper composite material panel, the flow channel layer, and the lower composite material panel are integrally formed.

2. The thin-walled composite material plate structure with internal hollow flow channels according to claim 1, characterized in that: The flexible braided sleeve is a three-dimensional braided tube, a two-dimensional braided tube, or a knitted tube, and the material of the flexible braided sleeve is one of glass fiber, carbon fiber, aramid fiber, or basalt fiber.

3. A thin-walled composite panel structure having internal stringers with hollow flow channels as defined in claim 2, wherein: The flexible braided sleeve has a removable polytetrafluoroethylene liner inside.

4. The thin-walled composite panel structure with internal stringer hollow flow channels of claim 1, wherein: The filler is short fibers or fabrics of glass fiber, carbon fiber, aramid fiber or basalt fiber.

5. A thin-walled composite panel structure having internal stringers with hollow flow channels as defined in claim 4, wherein: The filler is made of the same material as the flexible braided sleeve.

6. A thin-walled composite panel structure having internal stringers with hollow flow channels as defined in claim 1, wherein: The flexible braided sleeve is partially fixedly connected to the upper composite material panel and the lower composite material panel by sutures or soluble fiber yarns.

7. A thin-walled composite material plate structure with an internal hollow flow channel according to claim 6, characterized in that: The sutures or soluble fiber yarns are spaced apart along the extension direction of the flexible braided sleeve.

8. A thin-walled composite material plate structure with internal hollow flow channels according to claim 1, characterized in that: The distance between the upper surface of the upper composite panel and the lower surface of the lower composite panel is 2 mm to 8 mm, and the thickness of both the upper and lower composite panels is 0.5 mm to 2 mm.

9. A thin-walled composite panel structure having internal stringers with hollow flow channels as defined in claim 8, wherein: The hollow flow channel has a height of 1 mm to 4 mm and a width of 10 mm to 30 mm.

10. The thin-walled composite panel structure with internal stringer hollow flow channels of claim 1, wherein: The resin matrix used in the composite molding is bismaleimide resin, epoxy resin, unsaturated polyester resin, or vinyl ester resin.

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