Combined die for preparing S-shaped folded core body made of fiber reinforced composite material

Abstract

The invention discloses a combined die for preparing a fiber reinforced composite S-shaped folded core body. The mold comprises a male mold single body, a female mold single body, a clamping block, a base, a bolt and a pin, the method has the advantages that compared with a honeycomb core body, the prepared folded core body is internally provided with an open channel along the wall face, fluid can pass through the core layer of the sandwich structure, face-core debonding caused by condensation of water vapor generated in the core layer is avoided, and it is guaranteed that the mechanical property of the fiber-reinforced folded sandwich structure is stable; compared with a corrugated core body, the prepared corrugated core body is of a three-dimensional periodic structure formed by folding a two-dimensional plane, the lateral bearing capacity of the core body is improved, and the anisotropy difference of mechanical properties in the plane is weakened; compared with the original Miura configuration, the crepe core body prepared by the invention translates the top ridge line by a certain distance to form a section of platform, so that the bonding area between the crepe core body and the panel is increased; in addition, bent ridges are changed into smooth curved surfaces, so that stress concentration at corners during bearing is avoided.

Description

Technical Field

[0001] The present invention belongs to the technical field of forming equipment, and particularly relates to a combined mold for preparing an S-shaped corrugated core of a fiber-reinforced composite material. Background Art

[0002] The sandwich structure has advantages such as high strength, lightweight, sound insulation, heat insulation, shock absorption and impact resistance compared with the single-layer plate structure, and thus has been widely used in the fields of aerospace, construction, transportation and the like.

[0003] Currently, the most widely used sandwich structure is the honeycomb structure. However, since its core is composed of sealed single cells, water vapor condensation is likely to occur, which will not only cause an increase in the structural weight, but also damage the face-core bonding interface. These factors will limit the further development of the honeycomb structure. The corrugated structure has excellent mechanical properties, continuous open channels and good designability, and has received extensive attention from scholars in recent years.

[0004] For the fiber-reinforced composite corrugated sandwich structure, the preparation and forming process is mostly the mold hot pressing method. The existing molds need to be pressurized by vacuum bag packaging. This process is relatively cumbersome, and if the vacuum bag is damaged, pressure relief will occur, making it difficult to ensure the quality of the finished product. Summary of the Invention

[0005] In order to solve the above problems, the purpose of the present invention is to provide a combined mold for preparing an S-shaped corrugated core of a fiber-reinforced composite material.

[0006] In order to achieve the above purpose, the combined mold for preparing an S-shaped corrugated core of a fiber-reinforced composite material provided by the present invention includes a male mold monomer, a female mold monomer, a clamping block, a base, bolts and pins; wherein, the base is a rectangular plate-like structure, horizontally arranged, with multiple rows of connection holes formed along the length in the middle, the connection holes in each row are spaced apart, two positioning holes are respectively formed at the two ends of each row of connection holes, and the positioning holes and the connection holes are on the same straight line; a through hole is formed in the middle between two adjacent rows of positioning holes, and a bolt hole is respectively formed at the position outside each through hole;

[0007] The middle part of the female mold monomer is the shaping part, and both ends are clamping parts; the clamping parts are plate-shaped, with two female mold positioning holes formed along the length direction in the middle, and a semi-circular groove is formed by the inward concavity of the middle parts of both side edges respectively; the shaping part has wavy upper and lower edges that are parallel to each other and is a gradually expanding structure from top to bottom, and fixing holes corresponding to the connection holes on the base are provided at the bottom; a plurality of female mold monomers are placed side by side on the top surface of the base in a close manner, and are positioned by aligning the four female mold positioning holes on the two clamping parts with the four positioning holes in the same row on the base, and the female mold monomers are fixed on the base by sequentially passing bolts through one connection hole in each row on the base and one fixing hole at the bottom of the female mold monomer;

[0008] The middle part of the male mold monomer is the shaping part, and both ends are clamping parts; the clamping parts are plate-shaped, and a pin hole is provided in the middle; the shaping part has wavy upper and lower edges that are parallel to each other and is a gradually shrinking structure from top to bottom; each male mold monomer is installed in the groove formed between two adjacent female mold monomers; each pin passes through a pin hole, a circular hole formed by two semi-circular grooves on two adjacent female mold monomers, and a corresponding through hole on the base from top to bottom in sequence to fix the male mold monomer on the base;

[0009] The clamping block is in an inverted "L" shape, and a through screw hole is provided in the central part in the vertical direction. The protruding part at the upper end contacts the top edge of one clamping part of each male mold monomer, and the lower end contacts the top surface of the base; each bolt is sequentially threadedly connected in the screw hole of a clamping block and a corresponding bolt hole on the base.

[0010] The height below the protruding part of the clamping block is equal to the sum of the heights of the clamping parts on the male mold monomer and the female mold monomer.

[0011] The male mold monomer, the female mold monomer, the clamping block and the base are all made of steel.

[0012] The shaping parts of the male mold monomer and the female mold monomer have the same structure, and they are placed side by side in a staggered manner along the same direction when installed.

[0013] The upper part of the male mold monomer is thicker.

[0014] The combined mold for preparing the fiber-reinforced composite material S-shaped corrugated core provided by the present invention has the following beneficial effects:

[0015] 1. Compared with the honeycomb core, the corrugated core prepared by the present invention has open channels along the wall surface inside, and the fluid can pass through the core layer of the sandwich structure, avoiding the generation of water vapor condensation inside and resulting in face-core debonding, and ensuring the stable mechanical properties of the fiber-reinforced corrugated sandwich structure;

[0016] 2. Compared with the corrugated core, the pleated core prepared by the present invention is a three-dimensional periodic structure formed by folding a two-dimensional plane, which improves the lateral bearing capacity of the core and reduces the anisotropic difference of mechanical properties in the plane;

[0017] 3. Compared with the original Miura configuration, the pleated core prepared by the present invention has its top ridgeline shifted a certain distance to form a platform, thereby increasing the bonding area with the panel; in addition, the bent ridgeline is changed into a smooth curved surface to avoid stress concentration at the corners when bearing loads;

[0018] 4. The combined mold of the present invention is simple in design and easy to process, which can effectively save the steel used in processing;

[0019] 5. There is a suitable inclination angle between the male mold monomer and the female mold monomer in the present invention, and the core body is easy to demould after molding;

[0020] 6. The combined mold of the present invention is reasonably designed. The male mold is split, and the female mold is fixed to the base by bolts to form a whole. The pressure required for core molding is given by bolts, which can save the packaging step and ensure the stability of pressure. Such a design can not only ensure the core molding, but also facilitate the disassembly and replacement of the mold. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A stereoscopic view of a combined mold for preparing an S-shaped corrugated core of a fiber-reinforced composite material provided by the present invention.

[0022] Figure 2 It is a three-dimensional image of the male mold unit in the combined mold with the bottom facing upward.

[0023] Figure 3 It is a three-dimensional diagram of the female mold unit in the combined mold.

[0024] Figure 4 This is a three-dimensional diagram of the clamping block in the combined mold.

[0025] Figure 5 This is a top view of the base in the combined mold. DETAILED DESCRIPTION

[0026] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0027] like Figures 1 - 5As shown in the figure, the combined mold for preparing the fiber-reinforced composite material S-shaped corrugated core body provided by the present invention includes a male mold monomer 1, a female mold monomer 2, a clamping block 3, a base 4, bolts 5 and pins 6; wherein, the base 4 is a rectangular plate-like structure, horizontally arranged, and multiple rows of connection holes 9 are formed along the length in the middle. The connection holes 9 in each row are arranged at intervals, and two positioning holes 8 are respectively formed at both ends of each row of connection holes 9, and the positioning holes 8 and the connection holes 9 are on the same straight line; a through hole 10 is formed in the middle between two adjacent rows of positioning holes 8, and a bolt hole 11 is respectively formed at the position outside each through hole 10;

[0028] The middle part of the female mold monomer 2 is a shaping part, and both ends are clamping parts; the clamping parts are plate-shaped, and two female mold positioning holes are formed along the length direction in the middle, and semi-circular grooves are respectively formed by inward indentation in the middle of both side edges; the shaping part has wavy upper and lower edges that are parallel to each other and is a gradually expanding structure from top to bottom, and fixing holes corresponding to the connection holes 9 on the base 4 are provided at the bottom; multiple female mold monomers 2 are placed side by side tightly on the top surface of the base 4, and are positioned by aligning the four female mold positioning holes on the two clamping parts with the four positioning holes 8 in the same row on the base 4, and the female mold monomers 2 are fixed on the base 4 by sequentially passing bolts through one connection hole 9 in each row on the base 4 and one fixing hole at the bottom of the female mold monomer 2;

[0029] The middle part of the male mold monomer 1 is a shaping part, and both ends are clamping parts; the clamping parts are plate-shaped, and a pin hole is provided in the middle; the shaping part has wavy upper and lower edges that are parallel to each other and is a gradually shrinking structure from top to bottom; each male mold monomer 1 is installed in the groove formed between two adjacent female mold monomers 2; each pin 6 passes through a pin hole, a circular hole formed by two semi-circular grooves on two adjacent female mold monomers 2, and a corresponding through hole 10 on the base 4 from top to bottom in sequence to fix the male mold monomer 1 on the base 4 to prevent uneven wall thickness of the core body caused by lateral displacement during its installation;

[0030] The clamping block 3 is in an inverted "L" shape, and a through screw hole is provided at the central part in the vertical direction. The protruding part at the upper end contacts the top edge of one clamping part of each male mold monomer 1, and the lower end contacts the top surface of the base 4; each bolt 5 is sequentially threadedly connected in a screw hole of a clamping block 3 and a corresponding bolt hole 11 on the base 4, thereby converting the pre-tightening force of the bolt 5 into the pressure on the male mold monomer 1, so as to press the male mold monomer 1 into the groove between two adjacent female mold monomers 2, making the mold closed to provide the pressure required for core body forming.

[0031] The height below the protruding part of the clamping block 3 is equal to the sum of the heights of the clamping parts on the male mold monomer 1 and the female mold monomer 2. This design realizes the precise control of the pressure and ensures that it is always maintained within the optimal range.

[0032] The male die monomer 1, female die monomer 2, clamping block 3 and base 4 are all made of steel, and this design can ensure the forming effect of the fiber-reinforced composite material S-shaped corrugated core.

[0033] The shaping parts of the male die monomer 1 and the female die monomer 2 have the same structure, and when they are installed, they are staggered and arranged side by side in the same direction. This design can ensure the coordinated deformation of the prepreg 7 during the folding process.

[0034] The upper part of the male die monomer 1 has a large thickness to improve its bending stiffness and prevent the male die monomer 1 from bending and deforming during the pressing process.

[0035] Now, the usage method of the combined mold for preparing the fiber-reinforced composite material S-shaped corrugated core provided by the present invention is described as follows:

[0036] Step 1, paving: Pave the prepreg 7 into a plate shape in the order of the designed angles.

[0037] Step 2, cleaning: Clean the surface of the mold to ensure that there are no sundries contaminating the surface of the prepreg 7.

[0038] Step 3, preheating: Spray the release agent onto the surface of the mold to facilitate demolding, and then put the whole mold into an oven and preheat it to 60°C.

[0039] Step 4, assembly: Place the above-mentioned paved prepreg 7 on the surface of the female die monomer 2. The preheating temperature of the mold will quickly soften the prepreg 7. Then, press each male die monomer 1 one by one in the same direction into the groove formed between adjacent female die monomers 2. After each male die monomer 1 is compacted, install the pin 6 to horizontally position the male die monomer 1, and then install the clamping block 3 and bolt 5 to apply pressure to the male die monomer 1 to fix the mold.

[0040] Step 5, curing: Put the assembled mold into an oven and paste the thermocouple, set the heating parameters of the oven according to the curing temperature curve required by the prepreg 7, and after setting, carry out heating and curing.

[0041] Step 6, demolding: After curing, wait for the mold to cool naturally to room temperature, disassemble the mold, and obtain the fiber-reinforced composite material S-shaped corrugated core.

Claims

1. A combined mold for preparing an S-shaped corrugated core of a fiber-reinforced composite material, characterized in that: The combined mold includes a male mold monomer (1), a female mold monomer (2), a clamping block (3), a base (4), bolts (5) and pins (6); wherein, the base (4) is a rectangular plate-like structure, horizontally arranged, with multiple rows of connection holes (9) formed along the length in the middle, the connection holes (9) in each row are arranged at intervals, and two positioning holes (8) are respectively formed at the two ends of each row of connection holes (9), and the positioning holes (8) and the connection holes (9) are on the same straight line; a through hole (10) is formed in the middle between two adjacent rows of positioning holes (8), and a bolt hole (11) is respectively formed at the part outside each through hole (10); The middle part of the female mold monomer (2) is a shaping part, and both ends are clamping parts; the clamping parts are plate-shaped, with two female mold positioning holes formed along the length direction in the middle, and a semi-circular groove is respectively formed by the inward concavity of the middle parts of the two side edges; the shaping part has wavy upper and lower edges that are parallel to each other and is a gradually expanding structure from top to bottom, and fixing holes corresponding to the connection holes (9) on the base (4) are provided at the bottom; multiple female mold monomers (2) are placed side by side tightly on the top surface of the base (4), and are positioned by aligning the four female mold positioning holes on the two clamping parts with the four positioning holes (8) in the same row on the base (4), and the female mold monomers (2) are fixed on the base (4) by sequentially passing bolts through one connection hole (9) in each row on the base (4) and one fixing hole at the bottom of the female mold monomer (2); The middle part of the male mold monomer (1) is a shaping part, and both ends are clamping parts; the clamping parts are plate-shaped, and a pin hole is provided in the middle; the shaping part has wavy upper and lower edges that are parallel to each other and is a gradually shrinking structure from top to bottom; each male mold monomer (1) is installed in the groove formed between two adjacent female mold monomers (2); each pin (6) passes through a pin hole, a circular hole formed by two semi-circular grooves on two adjacent female mold monomers (2) and a corresponding through hole (10) on the base (4) from top to bottom in sequence to fix the male mold monomer (1) on the base (4); The clamping block (3) is in an inverted "L" shape, with a through screw hole provided at the central part in the vertical direction, the protruding part at the upper end contacts the top edge of a clamping part of each male mold monomer (1), and the lower end contacts the top surface of the base (4); each bolt (5) is sequentially threadedly connected in the screw hole of a clamping block (3) and a corresponding bolt hole (11) on the base (4).

2. The combined mold for preparing the fiber-reinforced composite material S-shaped corrugated core according to claim 1, characterized in that: The height of the clamping block (3) below the protruding part is equal to the sum of the heights of the clamping parts of the male mold monomer (1) and the female mold monomer (2).

3. The combined mold for preparing the fiber-reinforced composite material S-shaped corrugated core according to claim 1, wherein: The male mold monomer (1), the female mold monomer (2), the clamping block (3) and the base (4) are all made of steel.

4. The combined mold for preparing the fiber-reinforced composite material S-shaped corrugated core according to claim 1, characterized in that: The shaping parts of the male mold monomer (1) and the female mold monomer (2) have the same structure, and they are arranged alternately side by side in the same direction when installed.

5. The combined mold for preparing the fiber-reinforced composite material S-shaped corrugated core according to claim 1, wherein: The upper part of the male mold monomer (1) has a larger thickness.

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