CN118082239A - Forming structure and forming method of composite joint - Google Patents

Forming structure and forming method of composite joint Download PDF

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Publication number
CN118082239A
CN118082239A CN202410195224.6A CN202410195224A CN118082239A CN 118082239 A CN118082239 A CN 118082239A CN 202410195224 A CN202410195224 A CN 202410195224A CN 118082239 A CN118082239 A CN 118082239A
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CN
China
Prior art keywords
composite joint
annular cylinder
top end
reinforcing rib
forming
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Application number
CN202410195224.6A
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Chinese (zh)
Inventor
常飞虎
李天明
李昌乐
黄凯
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Hubei Sanjiang Space Jiangbei Mechanical Engineering Co Ltd
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Hubei Sanjiang Space Jiangbei Mechanical Engineering Co Ltd
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Application filed by Hubei Sanjiang Space Jiangbei Mechanical Engineering Co Ltd filed Critical Hubei Sanjiang Space Jiangbei Mechanical Engineering Co Ltd
Priority to CN202410195224.6A priority Critical patent/CN118082239A/en
Publication of CN118082239A publication Critical patent/CN118082239A/en
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Abstract

The invention discloses a forming structure and a forming method of a composite joint. The forming structure comprises a composite joint body, wherein the composite joint body comprises an annular cylinder, a plurality of through holes are formed in the annular cylinder and are circumferentially arranged, and metal inserts matched with the through holes are embedded in each through hole; the periphery of the annular cylinder is radially extended with a plurality of reinforcing rib blocks which are arranged at intervals, and the bottom end surface of each reinforcing rib block is larger than the top end surface; the top end face of the annular cylinder, the top end faces and the outer side faces of all the reinforcing rib blocks are jointly attached with a skin; the skin comprises ellipsoids covering the top end surfaces and the outer side surfaces of all the reinforcing rib blocks and a paving surface covering the top end surfaces of the annular cylinders, and a flanging extending towards the axial direction is arranged at the joint of the paving surface and the paving surface. The invention fully plays the characteristic of designability of the composite material, reduces the negative quality of the joint, and achieves the aim of weight reduction of the composite material shell as much as possible.

Description

Forming structure and forming method of composite joint
Technical Field
The invention relates to the technical field of manufacturing of space solid rocket engines, in particular to a forming structure and a forming method of a composite joint.
Background
In the large environment where the traditional single-phase materials are continuously replaced by advanced functional composite materials, more and more composite material preparation technologies are generated to cater to the composite material market with high specificity, high functionality and low cost.
The joint is an important structure for realizing bearing and connection of the composite material shell, and the traditional joint material is of a metal structure, but the metal joint has large negative weight and has larger limitation on the requirement of the shell on weight reduction.
At present, the existing composite joint is mainly formed by replacing composite materials on the basis of a metal joint structure, and prepreg layering compression molding is generally adopted, but for a large-thickness composite material structure, the interlayer strength is obviously weaker than other performances, the damage form is mainly layering, and the excellent performances of the composite material cannot be fully exerted.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a forming structure and a forming method of a composite joint, which fully exert the designability characteristic of a composite material, reduce the negative quality of the joint and realize the weight reduction aim of a composite material shell as far as possible.
In order to achieve the above object, the present invention provides a composite joint molding structure, comprising a composite joint body, which is characterized in that: the composite joint body comprises an annular cylinder, a plurality of through holes are circumferentially arranged in the annular cylinder, each through hole extends from the bottom end face to the top end face of the annular cylinder, and a metal insert matched with the through hole is embedded in each through hole;
the periphery of the annular cylinder is radially extended with a plurality of reinforcing rib blocks which are arranged at intervals;
The top end surfaces of the annular cylinders and the top end surfaces and the outer side surfaces of all the reinforcing rib blocks are jointly attached with a skin, and the skin is used for connecting the top end surfaces of the annular cylinders and the top end surfaces and the outer side surfaces of all the reinforcing rib blocks into a whole; the skin is including covering the ellipsoid of all stiffening rib block top end surfaces, lateral surface and covering the shop plane at the annular cylinder top end surface, the inside cutting of shop plane has the screw hole with the through-hole one-to-one, shop slope face and shop plane junction are provided with the turn-ups towards axial extension.
Further, the sum of the height of the annular cylinder and the thickness of the paving surface is less than or equal to 27mm, the diameter of the skin is 30-40 mm, and the shoulder width ratio of the skin is 1.2-1.4.
Still further, the contact surface of the metal insert and the through hole is provided with a sawtooth-shaped groove.
The invention also designs a forming method of the composite joint, which is suitable for the forming structure of the composite joint, and is characterized by comprising the following steps:
S1) finishing the braiding molding of the composite joint body;
taking all the reinforcing rib blocks around and the annular cylinder in the middle as a whole, and carrying out integral braiding molding; or weaving all the reinforcing rib blocks and the annular cylinders in a blocking manner, and then sewing the annular cylinders with all the reinforcing rib blocks;
3D integral braiding is carried out on the skin, and the structural strength of each part is ensured; or dividing the skin into an ellipsoid, a plane and a flanging, respectively weaving each part in 2.5D, and then sewing the ellipsoid, the plane and the flanging;
S2) designing and manufacturing a curing mold matched with the composite joint, and performing pretreatment on the curing mold;
S3) placing the composite joint body into a female die of a curing die, closing the die, pre-compacting, opening the die after a period of time, and filling the part with fiber tows at the meat deficiency position;
s4) embedding the metal insert into the composite joint body;
S5) closing the die, and connecting the curing die with an auxiliary pipeline;
S6) injecting the resin into a curing mold at normal temperature;
s7) after resin injection is finished, closing a glue outlet, and pressurizing a glue injection tank;
S8) heating and curing the curing mold, and demolding the product after curing.
Further, in S1), when the 3D integral knitting is performed on the skin, the outermost layer is continuously knitted on the ellipsoid and the flat surface, the single layer is knitted and thickened in the thickest direction of the inner diameter, and the single layer is longitudinally stitched and molded every 5mm in the thickness direction.
Further, in S1), the weaving parameters are 6K multiplied by 2 strands of warp yarns and the warp density is 8-10 pieces/cm; 6 Kx1-2 strands of weft yarns and 2.5-3.5 weft yarns/cm.
Further, in S1), when the skin is segmented 2.5D knitted, unidirectional fabric filling is used in the corner regions.
Further, in S2), the pretreatment of the curing mold includes degreasing, rust removal, hole sealing agent application and release agent application.
Further, in S6), the resin is an epoxy resin, the pot life of the resin is greater than or equal to 6 hours, and the viscosity in the glue injection process is less than or equal to 500cps.
Further, step S9) is included to trim and detect the quality of the product.
The invention has the advantages that:
1. The invention adopts the injection molding curing process of the prefabricated body to develop the composite joint, the composite joint body in the invention is divided into two parts, one part is an annular cylinder and a reinforcing rib block, the other part is a skin, the invention firstly carries out block knitting integral stitching or integral knitting on the integral formed by the annular cylinder and the reinforcing rib block or the integral formed by the skin, then carries out precompaction on the composite joint body, pre-embeds the metal insert in the composite joint body, and finally places the composite joint body into a curing mold for injection molding curing;
2. According to the invention, the circumferentially arranged reinforcing rib blocks are arranged on the periphery of the annular cylinder, the circumferentially arranged metal inserts are pre-embedded in the annular cylinder, and then the skin is paved on the tops of the annular cylinder and the reinforcing rib blocks, so that the weight of the composite material shell is reduced, and the negative quality of the joint is reduced;
The forming structure and the forming method of the composite joint adopt the injection molding curing process of the preform to develop the composite joint, fully exert the designability characteristic of the composite material, reduce the negative quality of the joint and realize the weight reduction aim of the composite material shell as far as possible.
Drawings
FIG. 1 is a schematic view of an explosion type structure of a forming structure of a composite joint in the present invention;
FIG. 2 is a schematic radial cross-sectional view of a molded structure of a composite joint according to the present invention;
FIG. 3 is a schematic top view of a composite joint forming structure according to the present invention;
FIG. 4 is a schematic bottom view of a composite joint forming structure according to the present invention;
FIG. 5 is a schematic perspective view of the metal insert of FIG. 1;
FIG. 6 is a flow chart of a method of forming a composite joint according to the present invention;
In the figure: a composite joint body 1 and a metal insert 2;
The composite joint body 1 includes: the steel plate comprises an annular cylinder 1-1, a reinforcing rib block 1-2, a skin 1-3 and a through hole 1-4;
the skin 1-3 comprises: 1-31 parts of ellipsoids, 1-32 parts of paving surfaces, 1-33 parts of threaded holes and 1-34 parts of flanging.
Detailed Description
The invention is described in further detail below with reference to the drawings and specific examples.
In the description of the present invention, it should be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like indicate orientations or positional relationships based on the orientation or positional relationships shown in the drawings, merely to facilitate describing the present invention and simplify the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the invention.
As shown in fig. 1 to 5, the forming structure of the composite joint of the invention comprises a composite joint body 1, wherein the composite joint body 1 comprises an annular cylinder 1-1, a plurality of through holes 1-4 are circumferentially arranged in the annular cylinder 1-1, each through hole 1-4 extends from the bottom end surface to the top end surface of the annular cylinder 1-1, and a metal insert 2 matched with the through hole 1-4 is embedded in each through hole 1-4.
Preferably, the metal insert 2 has a T-shaped structure with a cavity, and the through holes 1-4 are corresponding T-shaped through holes.
The periphery of the annular cylinder 1-1 is radially extended with a plurality of reinforcing rib blocks 1-2 which are arranged at intervals. In this embodiment, the top end surface of each reinforcing rib block 1-2 is flush with the top end surface of the annular cylinder 1-1, the bottom end surface is flush with the bottom end surface of the annular cylinder 1-1, and the bottom end surface of each reinforcing rib block 1-2 is larger than the top end surface.
The top end face of the annular cylinder 1-1 and the top end faces and the outer side faces of all the reinforcing rib blocks 1-2 are jointly attached with a skin 1-3, and the skin 1-3 is used for connecting the top end face of the annular cylinder 1-1 and the top end faces and the outer side faces of all the reinforcing rib blocks 1-2 into a whole; the skin 1-3 comprises ellipsoidal surfaces 1-31 covering the top end surfaces and the outer side surfaces of all the reinforcing rib blocks 1-2 and a paving surface 1-32 covering the top end surfaces of the annular cylinders 1-1, threaded holes 1-33 in one-to-one correspondence with the through holes 1-4 are cut in the paving surface 1-32, and flanges 1-34 extending towards the axial direction are arranged at the joint of the paving surface 1-31 and the paving surface 1-32.
The total mass of the composite joint is less than or equal to 1.5kg.
The sum of the height of the annular cylinder 1-1 and the thickness of the paving plane 1-32 is less than or equal to 27mm, the diameter of the skin 1-3 is 30-40 mm, and the shoulder-to-width ratio of the skin 1-3 is 1.2-1.4.
Preferably, the contact surface of the metal insert 2 and the through holes 1-4 is provided with saw-tooth grooves.
The invention adopts a prefabrication injection molding curing process to develop a composite joint, wherein a composite joint body 1 is divided into two parts, one part is an annular cylinder 1-1 and a reinforcing rib block 1-2, the other part is a skin 1-3, the invention firstly carries out block knitting and integral stitching or integral knitting on the whole body formed by the annular cylinder 1-1 and the reinforcing rib block 1-2 or the whole body formed by the skin 1-3 respectively, then carries out precompaction on the composite joint body 1, pre-embeds a metal insert 2 in the composite joint body 1, and finally places the composite joint body 1 into a curing mold for injection molding curing.
As shown in fig. 6, the present invention further designs a method for forming a composite joint, which is applicable to the above-mentioned forming structure of a composite joint, and includes the following steps:
S1) finishing the braiding molding of the composite joint body 1.
All the reinforcing rib blocks 1-2 around and the annular cylinder 1-1 in the middle are taken as a whole to be integrally woven and formed, so that the weaving and forming difficulty of the prefabricated body can be reduced; or all the reinforcing rib blocks 1-2 and the annular cylinder 1-1 are woven in blocks, and then the annular cylinder 1-1 is sewn with all the reinforcing rib blocks 1-2.
3D integral braiding is carried out on the skins 1-3, and the structural strength of each part is ensured; or dividing the skin 1-3 into three parts of an ellipsoid 1-31, a paving surface 1-32 and a flanging 1-34, respectively weaving each part by 2.5D, and then sewing the ellipsoid 1-31, the paving surface 1-32 and the flanging 1-34.
Preferably, when 3D integral braiding is carried out on the skin 1-3, the outermost layer is continuously braided on the ellipsoidal surface 1-31 and the paving surface 1-32, the single-layer braiding is thickened in the thickest direction of the inner diameter, and the single-layer braiding is longitudinally stitched and formed every 5mm in the thickness direction.
Specifically, the weaving parameters are warp 6 Kx2 strands, warp density is 8-10 pieces/cm; 6 Kx1-2 strands of weft yarns and 2.5-3.5 weft yarns/cm.
Preferably, the skin 1-3 is segmented 2.5D knitted using unidirectional fabric filling in the corner areas.
S2) designing and manufacturing a curing mold matched with the composite joint, and performing pretreatment on the curing mold.
Specifically, the pretreatment of the curing mold comprises degreasing, rust removal, hole sealing agent coating and release agent coating.
S3) placing the composite joint body 1 into a female die of a curing die, closing the die, pre-compacting, placing for a period of time, opening the die, and filling the part with the fiber tows at the position of meat deficiency.
Specifically, the mold was opened after leaving for one night.
S4) embedding the metal insert 2 into the composite joint body 1.
Specifically, the composite joint body 1 and the metal insert 2 are realized in a sleeved bonding mode, after the surface of the metal insert 2 is subjected to sand blasting treatment, CH-31 adhesive is smeared on the surface of the metal insert 2, and the metal insert 2 is sleeved in the joint through hole 1-4 for solidification molding. Or a plurality of sawtooth grooves are added between the contact surfaces of the metal insert 2 and the composite joint body 1, so that the binding force of the metal piece and the composite material piece is increased.
S5) closing the die, and connecting the curing die with an auxiliary pipeline.
S6) injecting the resin into a curing mold at normal temperature.
Specifically, the resin is epoxy resin, the pot life of the resin is more than or equal to 6 hours, and the viscosity in the glue injection process is less than or equal to 500cps.
And S7) closing the glue outlet after the resin injection is finished, and pressurizing the glue injection tank.
S8) heating and curing the curing mold, and demolding the product after curing.
The forming method further comprises a step S9) of trimming and quality detecting the product.
The quality detection comprises the step of carrying out a limit bearing test on the composite joint, wherein the hydraulic bearing is required to be more than or equal to 18MPa.
According to the invention, the circumferentially arranged reinforcing rib blocks 1-2 are arranged on the periphery of the annular cylinder 1-1, the circumferentially arranged metal inserts 2 are pre-embedded in the annular cylinder 1-1, and then the skins 1-3 are paved on the tops of the annular cylinder 1-1 and the reinforcing rib blocks 1-2, so that the weight of the composite shell is reduced, and the negative quality of the joint is reduced.
The forming structure and the forming method of the composite joint adopt the injection molding curing process of the preform to develop the composite joint, fully exert the designability characteristic of the composite material, reduce the negative quality of the joint and realize the weight reduction aim of the composite material shell as far as possible.
The foregoing is a preferred embodiment of the invention, but the embodiments of the invention are not limited to the above examples, and any other changes, modifications, substitutions, combinations, and simplifications that do not depart from the spirit and principles of the invention should be made therein and are intended to be equivalent substitutions within the scope of the invention.

Claims (10)

1. The utility model provides a shaping structure of compound joint, includes compound joint body (1), its characterized in that: the composite joint body (1) comprises an annular cylinder (1-1), wherein a plurality of through holes (1-4) are formed in the annular cylinder (1-1) and are circumferentially arranged, each through hole (1-4) extends from the bottom end surface to the top end surface of the annular cylinder (1-1), and a metal insert (2) matched with the through hole (1-4) is embedded in each through hole (1-4);
The periphery of the annular cylinder (1-1) is radially extended with a plurality of reinforcement rib blocks (1-2) which are arranged at intervals;
The top end face of the annular cylinder (1-1) and the top end faces and the outer side faces of all the reinforcing rib blocks (1-2) are jointly attached with a skin (1-3), and the skin (1-3) is used for connecting the top end face of the annular cylinder (1-1) and the top end faces and the outer side faces of all the reinforcing rib blocks (1-2) into a whole; the skin (1-3) comprises ellipsoidal surfaces (1-31) covering the top end surfaces and the outer side surfaces of all the reinforcing rib blocks (1-2) and a paving surface (1-32) covering the top end surfaces of the annular cylinders (1-1), threaded holes (1-33) in one-to-one correspondence with the through holes (1-4) are formed in the paving surface (1-32), and flanges (1-34) extending towards the axial direction are arranged at the joint of the paving surface (1-31) and the paving surface (1-32).
2. The composite joint forming structure according to claim 1, wherein: the sum of the height of the annular cylinder (1-1) and the thickness of the paving surface (1-32) is less than or equal to 27mm, the diameter of the skin (1-3) is 30-40 mm, and the shoulder-to-width ratio of the skin (1-3) is 1.2-1.4.
3. The composite joint forming structure according to claim 2, wherein: the contact surface of the metal insert (2) and the through hole (1-4) is provided with a sawtooth-shaped groove.
4. A method of forming a composite joint, adapted to the composite joint forming structure according to any one of claims 1 to 3, comprising the steps of:
s1) finishing the braiding molding of the composite joint body (1);
taking all the surrounding reinforcing rib blocks (1-2) and the middle annular cylinder (1-1) as a whole, and carrying out integral braiding molding; or all the reinforcing rib blocks (1-2) and the annular cylinder (1-1) are woven in a block mode, and then the annular cylinder (1-1) is sewn with all the reinforcing rib blocks (1-2);
3D integral braiding is carried out on the skins (1-3), and the structural strength of each part is ensured; or dividing the skin (1-3) into an ellipsoid (1-31), a paving plane (1-32) and a flanging (1-34), respectively weaving each part in 2.5D, and then sewing the ellipsoid (1-31), the paving plane (1-32) and the flanging (1-34);
S2) designing and manufacturing a curing mold matched with the composite joint, and performing pretreatment on the curing mold;
s3) placing the composite joint body (1) into a female die of a curing die, closing the die, pre-compacting, opening the die after a period of time, and filling the part with fiber tows at the meat deficiency position;
S4) embedding the metal insert (2) into the composite joint body (1);
S5) closing the die, and connecting the curing die with an auxiliary pipeline;
S6) injecting the resin into a curing mold at normal temperature;
s7) after resin injection is finished, closing a glue outlet, and pressurizing a glue injection tank;
S8) heating and curing the curing mold, and demolding the product after curing.
5. The method of forming a composite joint according to claim 4, wherein: in S1), when 3D integral braiding is carried out on the skin (1-3), continuously braiding the outermost layer on the ellipsoidal surface (1-31) and the paving surface (1-32), braiding and thickening in a single layer in the thickest direction of the inner diameter, and simultaneously longitudinally sewing and forming every 5mm in the thickness direction in a staggered manner.
6. The method of forming a composite joint according to claim 5, wherein: s1), weaving parameters are 6K multiplied by 2 strands of warp yarns, and warp density is 8-10 pieces/cm; 6 Kx1-2 strands of weft yarns and 2.5-3.5 weft yarns/cm.
7. The method of forming a composite joint according to claim 4, wherein: in S1), when the skins (1-3) are subjected to segmented 2.5D weaving, unidirectional fabric filling is used in corner areas.
8. The method of forming a composite joint according to claim 7, wherein: s2), pretreatment of the curing mold comprises degreasing, rust removal, hole sealing agent coating and release agent coating.
9. The method of forming a composite joint according to claim 8, wherein: s6), the resin is epoxy resin, the pot life of the resin is more than or equal to 6 hours, and the viscosity in the glue injection process is less than or equal to 500cps.
10. The method of forming a composite joint according to claim 4, wherein: and S9), trimming and quality detection are carried out on the product.
CN202410195224.6A 2024-02-22 2024-02-22 Forming structure and forming method of composite joint Pending CN118082239A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202410195224.6A CN118082239A (en) 2024-02-22 2024-02-22 Forming structure and forming method of composite joint

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202410195224.6A CN118082239A (en) 2024-02-22 2024-02-22 Forming structure and forming method of composite joint

Publications (1)

Publication Number Publication Date
CN118082239A true CN118082239A (en) 2024-05-28

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ID=91158195

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202410195224.6A Pending CN118082239A (en) 2024-02-22 2024-02-22 Forming structure and forming method of composite joint

Country Status (1)

Country Link
CN (1) CN118082239A (en)

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