A method for manufacturing a full composite rod with a joint

Abstract

This invention discloses a method for preparing a fully composite material rod with joints, belonging to the field of composite material connection technology. The method includes the following steps: S10, preparing a composite material rod body, pre-processing both ends of the composite material rod body with a rod body mold, removing the rod body mold after pre-processing to form the rod body component; S20, molding the composite material joint and composite material transition piece separately, then pressurizing and merging the composite material joint and composite material transition piece into a connecting joint; S30, integrally molding the connecting joint and the rod body component, and pressurizing and curing to complete the fully composite material rod product with joints. The fully composite material rod prepared by this invention has no metal parts, no fasteners, and minimizes thermal stress at high temperatures; the mold processing is simple, with no special processing required for the rod mold, connecting piece mold, and transition piece mold; the fiber continuity between the rod and the joint is good, ensuring the stress performance of the rod.

Description

Technical Field

[0001] This invention belongs to the field of composite material connection technology, and more specifically relates to a method for preparing a fully composite material rod with joints. Background Technology

[0002] Composite material bonding is one of the challenges in the application of composite material structures, especially in the aerospace and satellite fields, where it is necessary to ensure the stability of structural dimensions and design the structure to have deformation that approaches zero expansion (10⁻⁶ m).

[0003] In existing technologies, composite materials have lower thermal expansion, while metal materials have higher thermal expansion. The connection of composite materials needs to be achieved through metal structures, which increases the design difficulty.

[0004] Therefore, there is an urgent need for a molding method for fully composite material rods with joints, which can realize the use of fully composite material components in single-piece structures and meet the dimensional deformation requirements of the structure. Summary of the Invention

[0005] The present invention aims to provide a molding method for a fully composite material rod with joints, realizing a single-piece structure with a fully composite material composition that can meet the dimensional deformation requirements of the structure.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing a fully composite rod with a joint includes the following steps: S10. Prepare a composite material rod body. The rod body mold is pre-processed at both ends of the composite material rod body. After pre-processing, the rod body mold is removed to form a rod body component. S20. The composite material joint and the composite material transition piece are formed separately, and then the composite material joint and the composite material transition piece are pressurized and merged into a connecting joint. S30. The connecting joint and the rod body are integrally formed and then pressure-cured to complete the all-composite material rod product containing the joint.

[0007] Furthermore, in step S10, the composite material rod is prepared using a lay-up, RTM, or winding process.

[0008] Further, in step S10, the rod mold is pre-processed at both ends of the composite rod, and the rod mold is removed after pre-processing to form the rod component, including the following steps: S11. After the composite material rod is prepared and cured, before demolding, the mold with rod body is used to process 3-5 grooves at both ends of the composite material rod; the width of the groove is 1 / 4D and the depth is 1 / 2t, where D is the outer diameter of the composite material rod and t is the wall thickness of the composite material rod; the mold with rod body is removed after the composite material rod is pre-processed. S12. Fill the grooves on both sides of the composite material rod with a prepreg fabric of the same width as the grooves in the circumferential direction of the composite material rod to form a rod preform; wherein, the wall thickness of the composite material rod is t, the groove depth is t / 2, and the single layer thickness of the prepreg fabric is h1, then the number of filling layers of the prepreg fabric n=t / 2 / h1. S13. After the groove is filled, since there will be a certain gap between the prepreg fabrics, the outside of the rod preform is pressurized to make the outside flat and form the rod part.

[0009] Furthermore, in step S13, a vacuum bag is wrapped around the outside of the precast rod, and the precast rod is pressurized using a vacuum bag pressing method for 1 hour.

[0010] Further, in step S20, the composite material transition component includes a chassis and a cylinder, with the cylinder fixed at the center of the chassis; the composite material transition component is formed in a transition component mold, the transition component mold including a chassis mold and two symmetrically arranged cylindrical cavity molds, each of the two cylindrical cavity molds having a semi-cylindrical cavity.

[0011] Furthermore, the composite material transition component is formed in the transition component mold as follows: S211. First, lay two layers of prepreg fabric on the bottom side and in the semi-cylindrical cavity of a single-sided cylindrical cavity mold. That is, lay the prepreg material in the cylindrical cavity of the mold and extend the fiber all the way to the edge of the base plate. In the base plate part, extend the prepreg material into a plane and fill the semi-cylindrical cavity according to the actual size. The other single-sided cylindrical cavity mold is operated in the same way. S212. The dimensions of the disc portion of the transition piece are calculated by subtracting the thickness of the two cylindrical cavity molds mentioned above formed in the chassis portion, with the remaining thickness completed in the chassis mold. S213. After the two cylindrical cavity molds and the chassis mold are formed, the two cylindrical cavity molds are first tightened and pressurized, and then the bottom of the two cylindrical cavity molds are connected to the upper part of the chassis mold and pressurized together for more than 3 hours to ensure the external dimensions.

[0012] Further, in step S20, the composite material joint includes a disc and a joint body installed at the center of the disc. The end of the joint body away from the disc is arc-shaped, and a through hole is provided on the joint body. The composite material joint is formed in a joint mold, which includes a forming disc mold and two symmetrically arranged forming joint body molds.

[0013] Furthermore, the composite material joint is formed in the joint mold as follows: The prepreg is cut at different angles of 0 / 90 / 45 / -45 degrees. The joint hole positions are directly cut by the cutting machine to avoid secondary processing. The quantity of prepreg is calculated according to the joint thickness. The prepreg is formed on one side of the main mold of the joint. The 0 / 45 / -45 degree prepreg is extended onto the forming disc mold until the thickness is filled. The remaining thickness is formed on the base of the forming disc mold with prepreg fabric. After the three parts of the forming disc mold and the two forming connector main body molds are formed, the two forming connector main body molds are first tightened and pressurized, and then the bottom of the two forming connector main body molds are connected to the top of the forming disc mold and pressurized together for more than 3 hours to ensure the external dimensions.

[0014] Furthermore, after the composite material joint and the composite material transition piece are formed separately, the composite material joint and the composite material transition piece are combined, and the composite material joint and the composite material transition piece are pressurized as a whole using a vacuum bag pressing method to form a connecting joint.

[0015] Further, in step S30, the specific process of integrally molding the connecting joint and the rod body and then pressing and curing them is as follows: S31. The cylindrical part of the composite material transition piece is 1-2 mm shorter than the inner side of the rod piece. The thickness of the cylindrical part is made up by using prepreg fabric. The prepreg fabric is extended along the cylinder to the inner and outer sides of the disc, all the way to the joint part, to ensure fiber continuity. Then the disc part is laid out separately with prepreg fabric. S32. Apply prepreg body resin to the inside of the rod body, and insert the cylindrical part of the connecting joint into the rod body. The body resin can increase the internal connection force. S33. After the connecting joint is inserted into the rod, a 1-2mm layer is laid separately on the outer side of both ends of the rod towards the two joints as a continuous outer layer. The outer layer is made of pre-impregnated fabric, and cuts are required at different parts such as corners and rounded corners. After the whole is formed, the two ends of the rod are 1-2mm higher than the middle of the rod, which also strengthens the connection at the ends. S34. After the integral molding is completed, the integral is pressurized using a pressure mold, which includes a composite material joint pressure mold and a rod component pressure mold. First, the rod body part is pressurized using the rod body pressure mold. Then, the joint part is pressurized using the composite material joint pressure mold, and the composite material joint pressure mold is connected to the rod body pressure mold. Pressure is applied to the disc at the end of the joint rod. After heating, curing, and demolding, the all-composite material rod product with the joint is completed.

[0016] Compared with the prior art, the present invention has the following beneficial effects: (1) All composite material rods, no metal parts, no fasteners, and thermal stress is minimized at high temperatures; (2) The mold processing is simple, and the molds for rods, connectors and transition parts do not require special processing; (3) The fiber continuity between the rod and the joint is good, which ensures the stress performance of the rod. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention 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 embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the overall structure of a fully composite material rod with joints; Figure 2 for Figure 1 Sectional view of AA; Figure 3 This is a schematic diagram of the composite material rod structure; Figure 4 for Figure 3 BB section view; Figure 5 This is a schematic diagram of the pre-processed composite material rod. Figure 6 for Figure 5 CC section view; Figure 7 A schematic diagram showing the filling of prepreg fabric into the grooves on both sides of a composite rod; Figure 8 This is a schematic diagram showing the completion of filling the grooves on both sides of the composite material rod. Figure 9 A schematic diagram of applying pressure to composite material rods using a vacuum bag compression method; Figure 10 This is a schematic diagram of the structure of the composite material rod after molding; Figure 11 This is a structural schematic diagram of the transition component; Figure 12 This is a structural schematic diagram of the transition piece mold; Figure 13 This is a schematic diagram of a single-sided cylindrical cavity mold. Figure 14 A schematic diagram of prepreg being laid inside a cylindrical mold; Figure 15 A schematic diagram of the chassis mold for the transition component; Figure 16This is a schematic diagram of the structure after the transition piece mold is assembled; Figure 17 This is a schematic diagram of the composite material joint structure; Figure 18 This is a schematic diagram of the joint mold structure; Figure 19 A schematic diagram of the structure of the prepreg for forming a disc mold; Figure 20 This is a schematic diagram of the structure of the mold for forming a disc; Figure 21 This is a schematic diagram of the structure after the connector mold is assembled; Figure 22 This is a schematic diagram of the structure of the composite material joint and the composite material transition component after molding. Figure 23 A schematic diagram of the pressurization process for merging into a connecting joint; Figure 24 This is a structural diagram showing the connection between the transition piece and the rod body. Figure 25 A schematic diagram of the structure for inserting the rod into the joint section; Figure 26 A schematic diagram showing the structure in which prepreg fabric is laid on the outside of the rod body towards the joints after the connecting joint is inserted; Figure 27 This is a schematic diagram of the pressure mold. Figure 28 This is a schematic diagram of a structure that applies pressure to the rod section; Figure 29 A schematic diagram of the structure for applying pressure to the joint and connecting it to the pressure mold of the rod body; Figure 30 This is a schematic diagram of the final product after heat curing and demolding. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Example 1

[0021] refer to Figure 1 - Figure 30 A method for preparing a fully composite rod with joints includes the following steps: S10. Prepare a composite material rod. The rod mold is pre-processed at both ends of the composite material rod. After pre-processing, the rod mold is removed to form the rod part. In this embodiment, the composite material rod is prepared using processes such as lay-up, RTM, or winding.

[0022] Specifically, the rod mold is pre-processed at both ends of the composite rod, and the rod mold is removed after pre-processing to form the rod component, including the following steps: S11. After the composite rod is prepared and cured, before demolding, the mold with rod body is used to process 3-5 grooves at both ends of the composite rod; the width of the groove is 1 / 4D and the depth is 1 / 2t, where D is the outer diameter of the composite rod and t is the wall thickness of the composite rod; the mold with rod body is removed after the composite rod is pre-processed. S12. Fill the grooves on both sides of the composite material rod with a prepreg fabric of the same width as the grooves in the circumferential direction of the composite material rod to form a rod preform; wherein, the wall thickness of the composite material rod is t, the groove depth is t / 2, and the single layer thickness of the prepreg fabric is h1, then the number of filling layers of the prepreg fabric n=t / 2 / h1. S13. After the groove is filled, since there will be a certain gap between the prepreg fabrics, the outside of the rod prefabricated part is pressurized to make its outside flat and form the rod part.

[0023] More specifically, a vacuum bag is wrapped around the outside of the precast rod, and the precast rod is pressurized using a vacuum bag pressing method for 1 hour.

[0024] S20. The composite material joint and the composite material transition piece are formed separately, and then the composite material joint and the composite material transition piece are pressurized and merged into a connecting joint. In this embodiment, the composite material transition part includes a chassis and a cylinder, with the cylinder fixed at the center of the chassis; the composite material transition part is 1-2 mm thinner than the final product, and the difference in size is made up by the final molding.

[0025] The composite material transition part is formed in the transition part mold, which includes a chassis mold and two symmetrically arranged cylindrical cavity molds, each of which has a semi-cylindrical cavity.

[0026] The composite material transition component is formed in the transition component mold as follows: S211. First, lay two layers of prepreg fabric on the bottom side and in the semi-cylindrical cavity of a single-sided cylindrical cavity mold. That is, lay the prepreg material in the cylindrical cavity of the mold and extend the fiber all the way to the edge of the base plate. In the base plate part, extend the prepreg material into a plane and fill the semi-cylindrical cavity according to the actual size. The other single-sided cylindrical cavity mold is operated in the same way. S212. The dimensions of the disc portion of the transition piece are calculated by subtracting the thickness of the two cylindrical cavity molds formed in the base portion, with the remaining thickness completed in the base mold. S213. After the two cylindrical cavity molds and the chassis mold are formed separately, the two cylindrical cavity molds are first tightened and pressurized. Then the bottom of the two cylindrical cavity molds is connected to the top of the chassis mold and pressurized together for more than 3 hours to ensure the external dimensions.

[0027] In this embodiment, the composite material joint includes a disc and a joint body installed at the center of the disc. The end of the joint body away from the disc is arc-shaped, and a through hole is provided on the joint body. The composite material joint is 1-2 mm thinner than the final product, and the difference in size is made up by the final molding.

[0028] The composite material joint is formed in a joint mold, which includes a forming disc mold and two symmetrically arranged forming joint body molds.

[0029] The composite material joint forming process in the joint mold is as follows: The prepreg is cut at different angles of 0 / 90 / 45 / -45 degrees. The joint hole positions are directly cut by the cutting machine to avoid secondary processing. The quantity of prepreg is calculated according to the joint thickness. The prepreg is formed on one side of the main mold of the joint. The 0 / 45 / -45 degree prepreg is extended onto the forming disc mold until the thickness is filled. The remaining thickness is formed on the base of the forming disc mold with prepreg fabric. After the three parts of the forming disc mold and the two forming connector main body molds are formed, the two forming connector main body molds are first tightened and pressurized, and then the bottom of the two forming connector main body molds are connected to the top of the forming disc mold and pressurized together for more than 3 hours to ensure the external dimensions.

[0030] After the composite material joint and the composite material transition piece are formed separately, they are combined and then pressurized as a whole using a vacuum bag pressing method to form a connecting joint.

[0031] S30. The connecting joint and the rod body are integrally formed and then pressure-cured to complete the all-composite material rod product containing the joint.

[0032] The specific process of integrally molding the connecting joint and the rod body and then applying pressure for curing is as follows: S31. The cylindrical part of the composite material transition piece is 1-2 mm shorter than the inner side of the rod part. The thickness of the cylindrical part is made up by using prepreg fabric. The prepreg fabric is extended along the cylinder to the inner and outer sides of the disc, all the way to the joint part, which can ensure the continuity of the fibers. Then the disc part is laid separately with prepreg fabric. S32. Apply prepreg body resin to the inside of the rod body, insert the cylindrical part of the connecting joint into the rod body, and the body resin can increase the internal connection force. S33. After the connecting joint is inserted into the rod body, a 1-2mm layer is laid separately on the outer side of both ends of the rod body towards the two joints as a continuous outer layer. The outer layer is made of pre-impregnated fabric, and cuts are required at different parts such as corners and rounded corners. After the whole is formed, the two ends of the rod body are 1-2mm higher than the middle of the rod body, which also strengthens the connection at the ends. S34. After the integral molding is completed, the integral is pressurized using a pressure mold, which includes a composite material joint pressure mold and a rod component pressure mold. Specifically, the rod body is first pressurized using a rod body pressure mold. Then, the joint is pressurized using a composite material joint pressure mold, which is connected to the rod body pressure mold. Pressure is applied to the disc at the end of the joint rod. After heating, curing, and demolding, the fully composite material rod product with the joint is completed.

[0033] The technical solutions of the present invention have been fully described above. It should be noted that the specific embodiments of the present invention are not limited to the above description. All technical solutions formed by those skilled in the art based on the spirit and essence of the present invention by adopting equivalent transformations or equivalent transformations in terms of structure, method or function fall within the protection scope of the present invention.

Claims

1. A method for preparing a fully composite material rod with a joint, characterized in that, Includes the following steps: S10. Prepare a composite material rod body. The rod body mold is pre-processed at both ends of the composite material rod body. After pre-processing, the rod body mold is removed to form a rod body component. S20. The composite material joint and the composite material transition piece are formed separately, and then the composite material joint and the composite material transition piece are pressurized and merged into a connecting joint. S30. The connecting joint and the rod body are integrally formed and then pressure-cured to complete the all-composite material rod product containing the joint.

2. The method for preparing a fully composite material rod with joints according to claim 1, characterized in that, In step S10, the composite material rod is prepared using lay-up, RTM, or winding processes.

3. The method for preparing a fully composite material rod with joints according to claim 1, characterized in that, In step S10, the rod mold is pre-processed at both ends of the composite rod, and the rod mold is removed after pre-processing to form the rod component, including the following steps: S11. After the composite material rod is prepared and cured, before demolding, the mold with rod body is used to process 3-5 grooves at both ends of the composite material rod; the width of the groove is 1 / 4D and the depth is 1 / 2t, where D is the outer diameter of the composite material rod and t is the wall thickness of the composite material rod; the mold with rod body is removed after the composite material rod is pre-processed. S12. Fill the grooves on both sides of the composite material rod with a prepreg fabric of the same width as the grooves in the circumferential direction of the composite material rod to form a rod preform; wherein, the wall thickness of the composite material rod is t, the groove depth is t / 2, and the single layer thickness of the prepreg fabric is h1, then the number of filling layers of the prepreg fabric n=t / 2 / h1. S13. After the groove is filled, since there will be a certain gap between the prepreg fabrics, the outside of the rod preform is pressurized to make the outside flat and form the rod part.

4. The method for preparing a fully composite material rod with joints according to claim 3, characterized in that, In step S13, a vacuum bag is wrapped around the outside of the precast rod, and the precast rod is pressurized using a vacuum bag pressing method for 1 hour.

5. The method for preparing a fully composite material rod with a joint according to claim 1, characterized in that, In step S20, the composite material transition component includes a chassis and a cylinder, with the cylinder fixed at the center of the chassis; the composite material transition component is formed in a transition component mold, which includes a chassis mold and two symmetrically arranged cylindrical cavity molds, each of which has a semi-cylindrical cavity.

6. The method for preparing a fully composite material rod with a joint according to claim 5, characterized in that, The composite material transition component is formed in the transition component mold as follows: S211. First, lay two layers of prepreg fabric on the bottom side and in the semi-cylindrical cavity of a single-sided cylindrical cavity mold. That is, lay the prepreg material in the cylindrical cavity of the mold and extend the fiber all the way to the edge of the base plate. In the base plate part, extend the prepreg material into a plane and fill the semi-cylindrical cavity according to the actual size. The other single-sided cylindrical cavity mold is operated in the same way. S212. The dimensions of the disc portion of the transition piece are calculated by subtracting the thickness of the two cylindrical cavity molds mentioned above formed in the chassis portion, with the remaining thickness completed in the chassis mold. S213. After the two cylindrical cavity molds and the chassis mold are formed, the two cylindrical cavity molds are first tightened and pressurized, and then the bottom of the two cylindrical cavity molds are connected to the upper part of the chassis mold and pressurized together for more than 3 hours to ensure the external dimensions.

7. The method for preparing a fully composite material rod with a joint according to claim 6, characterized in that, In step S20, the composite material joint includes a disc and a joint body installed at the center of the disc. The end of the joint body away from the disc is arc-shaped, and a through hole is provided on the joint body. The composite material joint is formed in a joint mold, which includes a forming disc mold and two symmetrically arranged forming joint body molds.

8. The method for preparing a jointed all-composite rod according to claim 7, characterized in that, The composite material joint is formed in the joint mold as follows: The prepreg is cut at different angles of 0 / 90 / 45 / -45 degrees. The joint hole positions are directly cut by the cutting machine to avoid secondary processing. The quantity of prepreg is calculated according to the joint thickness. The prepreg is formed on one side of the main mold of the joint. The 0 / 45 / -45 degree prepreg is extended onto the forming disc mold until the thickness is filled. The remaining thickness is formed on the base of the forming disc mold with prepreg fabric. After the three parts of the forming disc mold and the two forming connector main body molds are formed, the two forming connector main body molds are first tightened and pressurized, and then the bottom of the two forming connector main body molds are connected to the top of the forming disc mold and pressurized together for more than 3 hours to ensure the external dimensions.

9. The method for preparing a jointed all-composite material rod according to claim 8, characterized in that, After the composite material joint and the composite material transition piece are formed separately, the composite material joint and the composite material transition piece are combined, and the composite material joint and the composite material transition piece are pressurized as a whole by vacuum bag pressing to form a connecting joint.

10. The method for preparing a jointed all-composite material rod according to claim 1, characterized in that, In step S30, the specific process of integrally forming the connecting joint and the rod body and then pressing and curing them is as follows: S31. The cylindrical part of the composite material transition piece is 1-2 mm shorter than the inner side of the rod piece. The thickness of the cylindrical part is made up by using prepreg fabric. The prepreg fabric is extended along the cylinder to the inner and outer sides of the disc, all the way to the joint part, to ensure fiber continuity. Then the disc part is laid out separately with prepreg fabric. S32. Apply prepreg body resin to the inside of the rod body, and insert the cylindrical part of the connecting joint into the rod body. The body resin can increase the internal connection force. S33. After the connecting joint is inserted into the rod, a 1-2mm layer is laid separately on the outer side of both ends of the rod towards the two joints as a continuous outer layer. The outer layer is made of pre-impregnated fabric, and cuts are required at different parts such as corners and rounded corners. After the whole is formed, the two ends of the rod are 1-2mm higher than the middle of the rod, which also strengthens the connection at the ends. S34. After the integral molding is completed, the integral is pressurized using a pressure mold, which includes a composite material joint pressure mold and a rod component pressure mold. First, the rod body part is pressurized using the rod body pressure mold. Then, the joint part is pressurized using the composite material joint pressure mold, and the composite material joint pressure mold is connected to the rod body pressure mold. Pressure is applied to the disc at the end of the joint rod. After heating, curing, and demolding, the all-composite material rod product with the joint is completed.

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