Composite grid shell with metal inserts and method of manufacturing thereof

Abstract

The application provides a composite grid cylinder with metal embedded parts and a preparation method of the composite grid cylinder, and relates to a forming method of a composite structure, which comprises the following steps: S1, laying hoop, longitudinal reinforcement and end frame and hot pre-pressing; S2, filling the gap between the metal embedded part and the pre-impregnated fiber body; S3, laying a sacrificial layer; S4, covering with a pressure equalizing plate and bagging; S5, entering the tank and pressing curing; S6, hot discharging; and S7, hot demolding. The application adopts a hot pre-pressing method by combining a hard mold with a pre-pressing adhesive strip, and the fiber accumulation at the intersection of the grid reinforcement strip is effectively controlled, so that the prepared composite grid cylinder has good grid structure size stability and high precision; by pre-embedding the metal part on the hard mold, the metal part is accurately positioned, and the problems of processing delamination and metal part easy to be pulled off caused by post-embedding of the metal part are avoided.

Description

Technical Field

[0001] This invention relates to a method for forming composite material structural components, specifically, to a composite material mesh cylinder with embedded metal parts and its preparation method. Background Technology

[0002] Composite mesh structures combine the advantages of advanced composite materials and mesh structures. Their products not only possess many advantages of fiber-reinforced composite materials, but also have the excellent performance of mesh structures. The main features include: (1) High structural efficiency. It has superior specific stiffness and specific strength, meets the requirements of lightweighting, and the strength utilization rate of the fiber can reach 95%. (2) Strong designability. Advanced composite mesh structures can achieve component optimization through the combination of material and structural design. (3) High damage tolerance. Compared with traditional composite structures, even if minor damage occurs, the load can be evenly transmitted along the remaining stiffeners. (4) Since the mesh structure is a relatively open spatial structure, it is convenient to realize the multi-functionality of structural design, and also facilitates the inspection and repair of products.

[0003] Currently, composite material mesh structure molding mainly includes free-form molding, lightweight foam molding, rigid mold molding, silicone rubber soft mold molding, hybrid mold molding, and expansion block mold molding. Among these, the rigid mold molding method produces mesh structures with good dimensional stability and high precision, but issues such as fiber accumulation at the intersections of mesh ribs and pressure transmission during curing need to be addressed during winding or laying. On the other hand, composite material mesh structures require external interfaces. For composite material mesh cylinders, metal components need to be placed at the end frames to connect with other mechanisms. Conventional methods for placing metal components include pre-embedding and post-embedding. However, for unidirectional fiber laminate structures, post-processed metal component mounting holes are prone to delamination, and post-bonded metal components have poor pull-out resistance because post-embedding with a tapered or stepped design to prevent pull-out is difficult. This means that three problems need to be solved through pre-embedding: ① accurate positioning of metal components; ② no delamination during metal component installation; ③ pull-out resistance of metal components. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a composite material mesh cylinder with embedded metal parts and its preparation method.

[0005] A method for preparing a composite mesh cylinder with embedded metal parts according to the present invention includes the following steps:

[0006] S1. Use prepreg yarn to lay ring ribs, longitudinal ribs and end frames on the rigid mold of the modular blocks, and pre-press it every 1mm during the process;

[0007] S2. Lay the metal embedded part to the thickness position of the metal embedded part and pre-press it again. Use positioning blocks and positioning screws to position the metal embedded part. Use pre-impregnated yarn to fill the gap between the metal embedded part and the pre-impregnated fiber body.

[0008] S3. After the thermal preloading to the theoretical thickness is completed, continue to lay a sacrificial layer of a certain thickness.

[0009] S4. Use a segmented pressure equalizing plate to cover the outer contour surface of the rigid mold and make bags;

[0010] S5. Pressurize and cure in the tank;

[0011] S6. Hot tapping, removing vacuum bags, and removing pressure equalization plates;

[0012] S7. Hot demolding: Remove the end strips, positioning blocks, and positioning screws. Then grind away the sacrificial layer that is higher than the hard mold. Finally, remove the split-type blocks from the core mold from both ends to the middle and take out the composite material mesh cylinder with metal embedded parts.

[0013] Preferably, in step S1 above, a composite material mesh cylinder with metal embedded parts is prepared using a rigid mold, and a volume magnification factor is designed at the intersection of the mesh ribs to achieve consistency of fiber volume content throughout the overall structure.

[0014] Preferably, in step S1 above, the orientation of the prepreg yarn at the intersection of the end frame and the longitudinal rib is as follows: the circumferential prepreg yarn is continuous in the circumferential direction, and the longitudinally divergent prepreg yarn is divergent in the longitudinal direction.

[0015] The width of the circumferential prepreg yarn is slightly smaller than the width of the end frame, forming a mold gap. This allows the longitudinally diverging prepreg yarn and the circumferential prepreg yarn at the intersection to transfer to the gap, reducing fiber accumulation.

[0016] Preferably, the number of prepreg layers to be added is calculated based on the width of the mold gap formed at the end frame, so as to ensure the consistency of fiber volume content throughout the overall structure.

[0017] Preferably, in step S1 above, the hot pre-pressing adopts a combination of pre-pressing strip and pressure equalizing plate. The width of the pre-pressing strip is the same as the cross-sectional width of the grid ribs, and the thickness is required to be higher than the outer surface of the rigid mold each time. This ensures that the pressure can be transmitted to the pre-impregnated fiber through the pre-pressing strip during the hot pre-pressing process, compressing and compacting the pre-impregnated fiber, and allowing the pre-impregnated fiber to unfold, slide, and fill the enlarged cavity.

[0018] Preferably, the thickness of the pre-compression strip in the hot pre-compression process is a combination of pre-compression strips of various thicknesses, and the thickness of the pre-compression strip is higher than the outer surface of the hard mold each time.

[0019] Preferably, in step S2 above, the metal embedded part undergoes surface roughening treatment and anti-pull-out design.

[0020] Preferably, in step S3 above, the sacrificial layer is laid so that the preimpregnated fiber is higher than the outer surface of the rigid mold, and the curing pressure can be transmitted to the mesh strip through the equalizing plate to compress and compact the preimpregnated fiber and prevent bridging.

[0021] Preferably, in steps S6 and S7 above, the hot exit temperature and hot demolding temperature are not lower than the prepreg resin gel temperature to prevent the rigid mold from thermally shrinking and squeezing to damage the composite material mesh cylinder with metal embedded parts.

[0022] The present invention also provides a composite material mesh cylinder with embedded metal parts, and adopts a method for preparing the composite material mesh cylinder with embedded metal parts.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] (1) The present invention uses a hot pre-pressing method by combining a rigid mold with a pre-pressing strip to effectively control the fiber accumulation at the intersection of the mesh ribs. The resulting composite material mesh cylinder has good dimensional stability and high precision.

[0025] (2) By pre-embedding metal parts on a hard mold, the present invention not only ensures accurate positioning of the metal parts, but also avoids the problems of processing delamination and easy pull-out of metal parts that are easily caused by post-embedding of metal parts. Attached Figure Description

[0026] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0027] Figure 1 This is a three-dimensional schematic diagram of the composite material mesh cylinder in this invention;

[0028] Figure 2 This is a schematic diagram of the composite material mesh cylinder in this invention.

[0029] Figure 3 This is a schematic diagram illustrating the use of the pre-compression adhesive strip in this invention;

[0030] Figure 4 This is a schematic diagram of the sacrificial layer of the mesh reinforcement in this invention;

[0031] Figure 5 This invention relates to the design of pre-impregnated yarn at the intersection of the end frame and the longitudinal rib.

[0032] Figure 6 This is a schematic diagram of the metal embedded parts in this invention;

[0033] Figure 7 for Figure 6 A sectional view.

[0034] The figure shows: circumferential prepreg yarn 101, longitudinally diverging prepreg yarn 102, split-type block 2, ring rib 3, longitudinal rib 4, end frame 5, metal embedded part 6, prepreg fiber body 7, sacrificial layer 8, pressure equalizing plate 9, cylinder core mold 10, pre-compression strip 11, mesh rib 12, and mesh rib intersection 120. Detailed Implementation

[0035] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0036] Example 1

[0037] According to the present invention, a method for preparing a composite material mesh cylinder with embedded metal parts is provided, such as... Figure 1-7 As shown, it includes the following steps:

[0038] S1. Use prepreg yarn to lay ring ribs 3, longitudinal ribs 4 and end frames 5 on the rigid mold of the split block 2. Among them, the mesh ribs 12 are 5mm wide and 12mm high, the end frames 5 are 24mm wide and 12mm high, and metal parts are pre-embedded at the end frames 5. During the process, heat pre-press once every 1mm.

[0039] S2. Lay the metal embedded part 6 at the thickness position and pre-press it again. Use positioning blocks and positioning screws to position the metal embedded part 6. Use pre-impregnated yarn to fill the gap between the metal embedded part 6 and the pre-impregnated fiber body 7.

[0040] S3. After the thermal preloading to the theoretical thickness is completed, continue to lay a sacrificial layer of a certain thickness 8.

[0041] S4. Use a segmented pressure equalizing plate 9 to cover the outer contour surface of the rigid mold and make a bag;

[0042] S5. Pressurize and cure in the tank;

[0043] S6. Hot tapping, remove vacuum bag, remove pressure equalization plate 9;

[0044] S7. Hot demolding: Remove the end strips, positioning blocks, and positioning screws. Then grind away the sacrificial layer 8 that is higher than the hard mold. Finally, remove the split-type assembly 2 from the core mold 10 from both ends to the middle and take out the composite material mesh cylinder with metal embedded parts.

[0045] In step S1 above, a composite material mesh cylinder with metal embedded parts is prepared using a hard mold. A volume magnification factor of 2 times is designed at the intersection of the mesh ribs at 120 to achieve the consistency of fiber volume content throughout the overall structure.

[0046] The orientation of the prepreg yarn at the intersection of end frame 5 and longitudinal rib 4: the circumferential prepreg yarn 101 is continuous in a circumferential direction, and the longitudinally divergent prepreg yarn 102 consists of 3 divergent lines. The circumferential prepreg yarn 101 is 23mm wide, and the end frame 5 is 24mm wide, forming a mold gap width of 1mm. This allows the longitudinally divergent prepreg yarn 102 and the circumferential prepreg yarn 101 at the intersection to shift towards the gap, reducing fiber accumulation. Based on the 1mm mold gap width, the end frame 5 requires 3 additional prepreg yarn layers. The thickness of a single prepreg yarn layer after curing is approximately 0.18mm, ensuring the consistency of fiber volume content throughout the overall structure.

[0047] Hot pre-pressing employs a combination of pre-pressing strip 11 and pressure equalizing plate 9. The pre-pressing strip is 5mm wide. During each hot pre-pressing process, the pre-pressing strip 11 is stacked in various thicknesses to ensure that its height exceeds the outer surface of the rigid mold. The width of the pre-pressing strip 11 is the same as the cross-sectional width of the grid ribs 12, and its thickness is required to exceed the outer surface of the rigid mold each time. This ensures that the pressure during hot pre-pressing can be transmitted to the pre-impregnated fiber body 7 through the pre-pressing strip 11, compressing and compacting the pre-impregnated fiber body 7, and allowing the pre-impregnated fiber body 7 to unfold, slide, and fill the enlarged cavity.

[0048] In step S2 above, the metal embedded part has a height of 10mm, a large end diameter of 7mm, a small end diameter of 6mm, an internal threaded blind hole, and an outer surface roughened by grinding.

[0049] In step S3 above, the sacrificial layer 8 is laid 0.6mm so that the preimpregnated fiber 7 is higher than the outer surface of the rigid mold. The curing pressure can be transmitted to the mesh reinforcement 12 through the equalizing plate 9 to compress and compact the preimpregnated fiber 7 and prevent bridging.

[0050] In steps S6 and S7 above, the hot exit temperature and hot demolding temperature are 120°C, which is higher than the prepreg resin gel temperature of 115°C, to prevent the composite material mesh cylinder with metal embedded parts from being damaged by thermal shrinkage and extrusion of the hard mold.

[0051] Example 2

[0052] The present invention also provides a composite material mesh cylinder with embedded metal parts, such as Figure 1-2 As shown, the mesh reinforcement strips are 5mm wide and 12mm high, the end frame is 24mm wide and 12mm high, and metal parts are embedded in the end frame. The composite mesh tube with embedded metal parts in Example 1 is prepared using the method for preparing composite mesh tubes.

[0053] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and 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. Therefore, they should not be construed as limitations on this application.

[0054] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A method of manufacturing a composite grid shell with metal inserts, characterized in that, Includes the following steps: S1. Use prepreg yarn to lay ring ribs (3), longitudinal ribs (4) and end frames (5) on the rigid mold of the split block (2), and pre-press it every 1mm during the process; S2. Lay the metal embedded part (6) at the thickness position and pre-press it again. Use positioning blocks and positioning screws to position the metal embedded part (6). Use the pre-impregnated yarn to fill the gap between the metal embedded part (6) and the pre-impregnated fiber body (7). S3. After the thermal preloading to the theoretical thickness is completed, continue to lay a sacrificial layer of a certain thickness (8). S4. Use a segmented pressure plate (9) to cover the outer contour surface of the rigid mold and make a bag; S5. Pressurize and cure in the tank; S6. Hot tapping, removing vacuum bag, and removing pressure equalization plate (9). S7. Hot demolding: Remove the end strips, positioning blocks, and positioning screws, then grind off the sacrificial layer (8) that is higher than the hard mold, and finally remove the split-type assembly (2) from the cylinder core mold (10) from both ends to the middle and take out the composite material mesh cylinder with metal embedded parts. In step S1 above, a composite material mesh cylinder with metal embedded parts is prepared using the hard mold. In the mold design, a volume magnification factor is designed at the intersection point (120) of the mesh ribs to achieve the consistency of fiber volume content in all parts of the overall structure. In step S1 above, the orientation of the prepreg yarn at the intersection of the end frame (5) and the longitudinal rib (4) is as follows: the circumferential prepreg yarn (101) is circumferentially continuous, and the longitudinally divergent prepreg yarn (102) is divergent. The width of the circumferential prepreg yarn (101) is slightly smaller than the width of the end frame (5), forming a mold gap, so that the longitudinally diverging prepreg yarn (102) and the circumferential prepreg yarn (101) at the cross node are transferred to the gap, reducing fiber accumulation; The number of prepreg yarn layers to be added is calculated based on the width of the mold gap formed at the end frame (5) to ensure the consistency of fiber volume content at all parts of the overall structure. In step S1 above, hot pre-pressing is performed by combining a pre-pressing strip (11) with the equalizing plate (9). The width of the pre-pressing strip (11) is the same as the cross-sectional width of the grid rib (12), and the thickness is required to be higher than the outer surface of the hard mold each time. This ensures that the pressure during hot pre-pressing can be transmitted to the pre-impregnated fiber body (7) through the pre-pressing strip (11), pressing and compacting the pre-impregnated fiber body (7), and causing the pre-impregnated fiber body (7) to unfold, slide, and fill the enlarged cavity. In step S3 above, the sacrificial layer (8) is laid so that the prepreg fiber (7) is higher than the outer surface of the rigid mold. The curing pressure can be transmitted to the mesh reinforcement (12) through the equalizing plate (9) to compress and compact the prepreg fiber (7) and prevent bridging.

2. The method for preparing a composite material mesh cylinder with embedded metal parts according to claim 1, characterized in that, The thickness of the pre-pressing strip (11) is composed of multiple thicknesses of the pre-pressing strip (11), and the thickness of the pre-pressing strip (11) is higher than the outer surface of the hard mold each time.

3. The method for preparing a composite material mesh cylinder with embedded metal parts according to claim 1, characterized in that, In step S2 above, the metal embedded part (6) undergoes surface roughening treatment and anti-pull-out design.

4. The method for preparing a composite mesh cylinder with embedded metal parts according to claim 1, characterized in that, In steps S6 and S7 above, the hot exit temperature and hot demolding temperature are not lower than the gel temperature of the prepreg resin to prevent the rigid mold from causing thermal shrinkage and extrusion damage to the composite material mesh cylinder with metal embedded parts.

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