Composite material tank forming die and method of manufacturing the same

Abstract

The application discloses a composite material storage tank forming die and a manufacturing method thereof, and belongs to the technical field of composite material forming dies. The composite material storage tank forming die is obtained by respectively and parallelly manufacturing a head connecting block, a head barrel segment connecting ring, a split barrel body assembly and a cap-shaped reinforcing rib and assembling them. The application guarantees the external shape of the die after combination, greatly reduces the self weight of the die, simplifies the die loading and die stripping process, leaves the head in the product after product forming, improves the strength and rigidity of the storage tank, and can provide a stable connecting interface.

Description

TECHNICAL FIELD

[0001] The present application relates to a composite material tank forming die and a manufacturing method thereof, and belongs to the technical field of composite material forming die. BACKGROUND

[0002] Resin-based composite materials are increasingly used in the fields of aviation, aerospace, etc. due to their low density, high specific strength and specific modulus, and good fatigue resistance. As an essential energy storage system for aircrafts, new energy vehicles, etc., pressure vessels gradually increase the use of composite materials in pursuit of extreme lightweight. Traditional composite pressure vessels use metal or plastic liners, and continuous fibers are wound or laid on the surface of the liner. After forming, the liner remains inside the container and serves as a sealing layer. The latest concept of V-type pressure vessels eliminates the obvious liner layer for extreme weight reduction, and directly uses continuous fiber composite materials to bear the load and achieve sealing. This brings great challenges to the laying, forming, demolding, and sealing assembly of fiber-reinforced composite materials. When facing large-sized forming tanks, the commonly used soluble core mold is too heavy, and its deformation control is difficult to guarantee. Traditional metal forming molds also face difficulties such as heavy weight, complex assembly, and thermal expansion mismatch. SUMMARY

[0003] The present application aims to provide a continuous fiber-reinforced resin-based composite tank forming die and a manufacturing method thereof. The forming die is assembled and disassembled through structures such as a barrel, a head, and a connecting ring. Under the condition of ensuring the overall rigidity of the die, the self-weight of the die is greatly reduced, the assembly difficulty and operation risk are lowered, and the forming efficiency of the composite tank is improved.

[0004] To achieve the above-mentioned purpose, the technical solution adopted by the present application is as follows:

[0005] A composite material tank forming die, comprising a large-end head connecting block, a split barrel assembly, a small-end head connecting block, a flange connecting block, a large-head barrel segment connecting ring, a small-head barrel segment connecting ring, and a cap-shaped reinforcing rib.

[0006] The flange connecting block is located at the first and last ends of the forming die.

[0007] The outer edge of the large-end head connecting block is connected to the large-head barrel segment connecting ring, and the inner edge is connected to the flange connecting block, which together form the forming support of the large-end head region of the tank.

[0008] The outer edge of the small-end head connecting block is connected to the small-head barrel segment connecting ring, and the inner edge is connected to the flange connecting block, which together form the forming support of the small-end head region of the tank.

[0009] The split cylinder assembly is spliced by several blocks, the blocks are thin skin long strips, and hat-shaped reinforcing ribs exist inside along the length direction of the storage tank; the split cylinder assembly is located between the large head cylinder segment connecting ring and the small head cylinder segment connecting ring, the head end of each block of the split cylinder assembly is connected with the large head cylinder segment connecting ring, and the tail end is connected with the small head cylinder segment connecting ring.

[0010] Preferably, the storage tank can be a cylindrical barrel structure or a barrel structure with a conical angle.

[0011] Preferably, the outer side of the large head cylinder segment connecting ring is provided with a supporting plate nut, each block of the split cylinder assembly is sequentially mechanically connected through a screw, and a draft angle is left in the connection area.

[0012] Preferably, the outer side of the small head cylinder segment connecting ring is provided with a supporting plate nut, each block of the split cylinder assembly is sequentially mechanically connected through a screw, and a draft angle is left in the connection area.

[0013] Preferably, each block of the split cylinder assembly is provided with a connecting flange around, a through hole and a supporting plate nut are sequentially arranged on the flange, and the flange is used to connect adjacent blocks and the large head cylinder segment connecting ring and the small head cylinder segment connecting ring.

[0014] Preferably, the main material of the forming mold is a fiber reinforced resin-based composite material, the fiber is a continuous carbon fiber, and the resin is a high-temperature curing epoxy resin or a bismaleimide resin; wherein the composition material of the hat-shaped reinforcing rib is a carbon fiber composite material skin and a PMI foam sandwich.

[0015] A manufacturing method of a composite material storage tank forming mold, comprising the following steps:

[0016] 1) using a metal negative mold, unidirectional prepreg is sequentially laid on the corresponding position of the surface of the metal negative mold according to the layering sequence, vacuum bag packaging is carried out, and hot press tank curing forming is carried out, and after demolding, the surface of the large and small head cylinder segment connecting ring fitting area is machined to obtain a large end head connecting block and a small end head connecting block;

[0017] 2) using a metal negative mold, unidirectional prepreg is sequentially laid on the corresponding position of the surface of the mold according to the layering sequence, vacuum bag packaging is carried out, and hot press tank curing forming is carried out, and after demolding, the block blank of the split cylinder assembly is obtained, the inner surface is polished to be rough using sandpaper, and after cleaning, it is ready for use;

[0018] 3) the block blank is fixed on the mold, the adhesive film is laid on the fitting surface of the block blank and the hat-shaped reinforcing rib, the foam sandwich with the corresponding shape is placed in the corresponding position, the unidirectional prepreg is laid on the surface according to the layering sequence, the whole is packaged by vacuum bag, and the hot press tank curing forming is carried out, and after demolding and shaping, the split cylinder assembly block with the hat-shaped reinforcing rib is obtained;

[0019] 4) The obtained sub-blocks are respectively matched with the screw mounting hole and the support plate nut mounting hole, the support plate nut is installed at the corresponding position, and all the sub-blocks are sequentially mechanically connected together in accordance with the assembly sequence to form a split cylinder body assembly;

[0020] 5) The unidirectional prepreg is sequentially laid according to the layering sequence to the corresponding position of the mold surface, vacuum bag packaging is performed, and hot press tank curing is performed to form a large end head cylinder segment connecting ring and a small end head cylinder segment connecting ring, which are respectively fixed at the corresponding position of the assembled split cylinder body assembly, and the screw hole and the support plate nut mounting hole are matched and punched, and the large and small end head cylinder segment connecting rings are removed and the corresponding support plate nuts are installed;

[0021] 6) The bonding surface of the large and small end head cylinder segment connecting rings and the large and small end head connecting blocks is cleaned, and the paste glue is applied, and the large end head cylinder segment connecting ring and the large end head connecting block are bonded, the small end head cylinder segment connecting ring and the small end head connecting block are bonded, and the corner area is filled and sealed, and the curing is performed at room temperature;

[0022] 7) The split cylinder body assembly is fixed with a bracket, the cured large and small end head connecting blocks are respectively fixed at the large and small ends of the split cylinder body assembly, and the split cylinder body assembly is connected with the large and small end head cylinder segment connecting rings by screws;

[0023] 8) The metal flange connecting block is installed at the corresponding position of the large and small end head connecting blocks by screws to obtain a composite tank forming mold.

[0024] Preferably, the layering form in step 1) is (0 / +45 / 90 / -45 / -45 / 90 / +45 / 0) n , wherein n is a positive integer according to the shape and requirements of the tank product.

[0025] Preferably, the layering form of the sub-blocks of the split cylinder body assembly in step 2) is (0 / +45 / 0 / -45 / 90 / -45 / 0 / +45 / 0) n , wherein n is a positive integer according to the shape and requirements of the tank product.

[0026] Preferably, the foam in step 3) is PMI foam with a compressive strength greater than 2.2 MPa, and the prepreg is alternately laid in 0° and ±45°, wherein the proportion of 0° is not less than 60%.

[0027] Preferably, in step 4), appropriate screws and support plate nuts should be selected according to the size of the product, and should meet the aviation industry standards.

[0028] Preferably, in step 4), the gap between the split cylinder body assembly sub-blocks after assembly should be less than 0.1 mm, and the step difference between the sub-blocks should be less than 0.1 mm.

[0029] Preferably, the laying form of the large and small end head cylinder segment connecting ring in step 5) is (0 / +45 / 90 / -45 / -45 / 90 / +45 / 0) n wherein n is a positive integer according to the shape and requirements of the storage tank product, and the fitting surface tolerance range after machining should be controlled within the interval of (-0.3, -0.1) mm.

[0030] Preferably, the adhesive used in step 6) is a room temperature curing paste structure adhesive, the adhesive layer thickness is 0.1-0.2 mm, and the room temperature curing time is not less than 24 h.

[0031] Preferably, the gap between the split cylinder body assembly and the large and small end head connecting block after assembly in step 7) should be not more than 0.1 mm, and the large and small end head connecting block should be not higher than the split cylinder body assembly, and the sinking depth is within the interval of (-0.5, 0) mm.

[0032] The beneficial effects of the present application compared with the prior art are:

[0033] (1) The forming mold of the present application adopts carbon fiber reinforced resin matrix composite material, the overall weight is greatly reduced, and the deflection deformation caused by its own weight is smaller compared with the traditional metal mold. This not only reduces the difficulty of mold loading and unloading, but also greatly reduces the danger of operation.

[0034] (2) Compared with the dissolvable core mold, the forming mold of the present application has the advantage of being reusable. There is no residual excess material when the mold is disassembled after forming, and the mold structure is simple, the profile precision is high, and the manufacturing cost is low. In addition, the split structure of the split cylinder body assembly of the mold includes a cap-shaped reinforcing rib along the axial direction, which effectively enhances the structural rigidity with less weight increase.

[0035] (3) The difference between the thermal expansion coefficient of the mold and the formed composite material is very small, which can accurately control the size of the composite material storage tank. The split assembly of the mold is connected and assembled with the core mold without relying on metal connecting rods, and is connected and supported by the head cylinder segment connecting ring and the head connecting block, which reduces the number of mold parts and facilitates the guarantee of profile precision.

[0036] (4) The forming mold of the present application uses a smaller shaft size during the fiber laying or winding process, and the deflection deformation caused by the mold itself is very small and almost negligible. This is more friendly to the chuck and transmission system of the winding machine and the fiber laying machine, significantly prolonging the service life.

[0037] (5) If partial damage occurs to the forming mold of the present application, it can be easily disassembled and replaced, and the replaced assembly can be quickly manufactured using the original metal mold, improving production efficiency.

[0038] (6) The mold forming method of the present application, the head connecting block and the head cylinder segment connecting ring will be left in the product, and they do not need to be taken out. They not only serve as the head reinforcing structure, but also provide a stable connecting interface for the subsequent internal anti-shaking plate and other equipment of the storage tank, reducing the need for secondary cementation or mechanical connection. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 is a schematic diagram of the overall composite material storage tank forming mold of the present application.

[0040] Figure 2 is a schematic diagram of the partial assembly of the composite material storage tank forming mold of the present application.

[0041] Figure 3 is a schematic diagram of the split cylinder body assembly of the composite material storage tank forming mold of the present application.

[0042] Figure 4 is a schematic diagram of the overall cross-section of the composite material storage tank forming mold of the present application. DETAILED DESCRIPTION

[0043] In order to make the above technical features and advantages or technical effects of the present application more obvious and easy to understand, the following embodiments are described in detail.

[0044] The present application provides a composite material storage tank forming mold, which can be a cylindrical cylinder body structure or a cylinder body structure with a conical angle, so as to Figures 1-4 As shown in the figure, the forming mold includes a large end head connecting block 1, a split cylinder body assembly 2, a small end head connecting block 3, a flange connecting block 4, a large head cylinder segment connecting ring 5, a small head cylinder segment connecting ring 6, a cap-shaped reinforcing rib 7, and a connecting fastener.

[0045] The large end head connecting block 1 is used to connect the large head cylinder segment connecting ring 5 and the flange connecting block 4, and together form the forming support of the large end head region of the storage tank. The opening size of the large end head connecting block 1 must be greater than the cross-sectional area of the largest split block in the split cylinder body assembly 2, and the large end head connecting block needs to ensure its air tightness. After the product is formed, the large end head connecting block remains in the product as part of the product head, playing a reinforcing role.

[0046] The split cylinder assembly 2 is spliced by several blocks, the blocks are thin skin long strips, and hat-shaped reinforcing ribs 7 exist in the blocks along the length direction of the storage tank. Each block is provided with connecting flanges around the block, and through holes and supporting plate nuts are sequentially arranged on the flanges, so that the adjacent blocks, the large end head cylinder segment connecting ring 5 and the small end head cylinder segment connecting ring 4 are connected. The principle of the blocks of the split cylinder assembly 2 is that the blocks are divided along the radius direction of the cross section in the length direction, the number of the blocks is as small as possible, but the cross-sectional area of the largest block is smaller than the opening size of the large end head connecting block, and one block needs to be firstly demolded along the radial direction, the flanges on the two sides of the block have a positive draft, and the remaining blocks are sequentially pressed flanges.

[0047] The small end head connecting block 3 is used for connecting the small end head cylinder segment connecting ring 6 and the flange connecting block 4, and together forms a forming support of the small end head region of the storage tank. The small end head connecting block needs to ensure the air tightness of the small end head connecting block. After the product is formed, the small end head connecting block remains in the product as a part of the product head, and plays a reinforcing role.

[0048] The flange connecting block 4 is located at the two ends of the mold, and is used for connecting the large end head connecting block 1 and the small end head connecting block 3 with a rotating rod or a supporting rod and the like transmission system during the laying or winding, and can also be connected with a cover or a conversion joint and the like device after the storage tank is formed.

[0049] The large end head cylinder segment connecting ring 5 is a circular ring with a cross section similar to an "L" shape, which is used for connecting the large end head connecting block 1 and each block of the split cylinder assembly 2. The supporting plate nuts are arranged on the outer side of the large end head cylinder segment connecting ring 5, and the blocks of the split cylinder assembly are sequentially mechanically connected through the screws. The connection area has a draft angle of about 2-5°, so that the blocks of the split cylinder assembly 2 can be demolded centripetally.

[0050] The small end head cylinder segment connecting ring 6 is a circular ring with a cross section similar to an "L" shape, which is used for connecting the small end head connecting block 3 and each block of the split cylinder assembly 2. The supporting plate nuts are arranged on the outer side of the small end head cylinder segment connecting ring 6, and the blocks of the split cylinder assembly are sequentially mechanically connected through the screws. The connection area has a draft angle of about 2-5°, so that the blocks of the split cylinder assembly 2 can be demolded centripetally.

[0051] The main material of the forming mold is a fiber reinforced resin-based composite material, the fiber is a continuous carbon fiber, and the resin is a high-temperature curing epoxy resin or a bismaleimide resin. The hat-shaped reinforcing rib 7 is a reinforcing structure of the block in the split cylinder assembly 2, and is composed of a carbon fiber composite material skin and a PMI foam sandwich, so as to increase the axial strength and rigidity of the block of the split cylinder assembly.

[0052] The application also provides a manufacturing method of the composite material storage tank forming mold, which comprises the following steps:

[0053] 1. Molding of large end head connection block 1 and small end head connection block 3: Use metal female mold to lay the unidirectional prepreg in the form of (0 / +45 / 90 / -45 / -45 / 90 / +45 / 0) n The layers are laid in the order of (n is a positive integer according to the shape and requirements of the storage tank product) to the corresponding positions on the metal negative model surface, vacuum bagged, and solidified in an autoclave. After demoulding, a machining center is used to machine the surface of the area where it fits with the large and small head barrel section connecting rings 5 ​​and 6 to obtain the large end head connecting block 1 and the small end head connecting block 3 respectively.

[0054] 2. Block molding of the split barrel assembly 2: Use a metal female mold to form the unidirectional prepreg according to (0 / +45 / 0 / -45 / 90 / -45 / 0 / +45 / 0) n The layers are laid in the order of (n is a positive integer according to the shape and requirements of the tank product) to the corresponding positions on the mold surface, vacuum bagged, and solidified in an autoclave. After demoulding, the block blanks are obtained. The inner surface is polished to a rough surface with sandpaper, cleaned and set aside.

[0055] 3. Forming the Hat-Shaped Ribs 7: The block blanks from step 2 are fixed to the mold. Adhesive film is applied to the surfaces that mate with the hat-shaped ribs. A foam core machined to the corresponding shape is placed in the corresponding position. PMI foam with a compressive strength greater than 2.2 MPa is selected. Unidirectional prepreg is applied to the surface in a layered pattern, alternating between 0° and ±45° angles, with 0° comprising no less than 60%. The block blanks are vacuum-baked, cured in an autoclave, and demolded to produce the split-flap barrel assembly with the hat-shaped ribs 7.

[0056] 4. According to steps 2 and 3, all the required segments of the split barrel assembly 2 and the hat-shaped reinforcement ribs 7 are formed and set aside.

[0057] 5. Assemble the split-type barrel assembly 2 in blocks: Punch the support plate nut mounting holes and screw mounting holes on the blocks formed in step 4 respectively. Select appropriate screws and support plate nuts according to the size of the product, which should comply with aviation industry standards. Install the support plate nuts in the corresponding positions. According to the assembly sequence, mechanically connect all the blocks together with screws to form the split-type barrel assembly 2. The gap after the split-type barrel assembly 2 is assembled should be less than 0.1mm, and the step difference between the blocks should be less than 0.1mm.

[0058] 6. Molding of the large head tube segment connecting ring 5 and the small head tube segment connecting ring 6: Use a metal male mold to mold the unidirectional prepreg according to (0 / +45 / 90 / -45 / -45 / 90 / +45 / 0) nThe n layers (where n is a positive integer according to the shape and requirements of the tank product) are sequentially laid on the corresponding positions of the mold surface, and after vacuum bagging, the hot press tank is cured and formed. After demolding, the machining center is used to machine the surface of the bonding area of the large and small end head connecting blocks 1 and 3. The tolerance range of the bonding surface after machining should be controlled within (-0.3, -0.1) mm. The large and small end head connecting rings 5 and 6 are obtained respectively, which are fixed at the corresponding positions of the split cylinder body assembly 2 assembled in step 5. The screw holes and support nut mounting holes are matched and punched, and the large and small end head connecting rings 5 and 6 are removed and the corresponding support nuts are installed.

[0059] 7. Bonding of the large end head connecting ring 5 and the large end head connecting block 1, and the small end head connecting ring 6 and the small end head connecting block 3: Clean the bonding surfaces of the large and small end head connecting rings 5 and 6 and the large and small end head connecting blocks 1 and 3, apply paste glue, and bond the large end head connecting ring 5 and the large end head connecting block 1, and the small end head connecting ring 6 and the small end head connecting block 3 respectively. Choose room temperature curing paste structure glue, the glue layer thickness is 0.1-0.2mm, the corner area is filled and sealed, and the curing time is not less than 24h at room temperature.

[0060] 8. Assembly of the split cylinder body assembly 2 and the large and small end head connecting blocks 1 and 3: The split cylinder body assembly 2 assembled in step 5 is fixed with a bracket, and the large and small end head connecting blocks 1 and 3 cured in step 7 are fixed at the large and small ends of the split cylinder body assembly 2 respectively. The split cylinder body assembly 2 is connected with the large and small end head connecting rings 5 and 6 by screws. The gap between the split cylinder body assembly 2 and the large and small end head connecting blocks 1 and 3 after assembly should be not more than 0.1mm, and the large and small end head connecting blocks 1 and 3 should be not higher than the split cylinder body assembly 2, with a sinking depth of (-0.5, 0) mm.

[0061] 9. Installation of the flange connecting block 4: The metal flange connecting block 4 is installed on the corresponding positions of the large and small end head connecting blocks 1 and 3 by screws, and is integrally installed on the corresponding positions of the winding machine or automatic fiber laying machine drive device to obtain a composite material forming mold.

[0062] A specific embodiment is provided below:

[0063] Example 1

[0064] The embodiment specifically discloses a composite material storage tank forming die, wherein the length of a split cylinder body assembly 2 is 2 m, the diameter of a large end head connecting block 1 is 1.2 m, the diameter of a small end head connecting block 3 is 1 m, the cylinder body taper angle is 2.86°, the manhole inner diameter of the large end head connecting block 1 is 440 mm, the manhole inner diameter of the small end head connecting block 3 is 304 mm, the head curve is elliptical, the split cylinder body assembly 2 has a block wall thickness of 3 mm, the large end head connecting block 1 has a wall thickness of 2 mm, the small end head connecting block 1 has a wall thickness of 2 mm, the large head cylinder segment connecting ring 5 has a wall thickness of 2 mm, the lap edge chord length is 86 mm, the connecting edge length is 50 mm, the small head cylinder segment connecting ring 6 has a wall thickness of 2 mm, the lap edge chord length is 86 mm, the connecting edge length is 50 mm, the cap-shaped reinforcing rib 7 has a skin thickness of 1.5 mm, and the foam is PMI foam with a density of 110 kg / m 3 and a compressive strength of 3.2 MPa.

[0065] The forming die material is T700-grade carbon fiber reinforced high-temperature epoxy resin composite material, except that the flange connecting block 4 is an aluminum alloy and the cap-shaped reinforcing rib 7 is PMI foam.

[0066] The large end head connecting block 1 is used for connecting the large head cylinder segment connecting ring 5 and the flange connecting block 4, and together forms a forming support of a large end head region of the storage tank, the large end head connecting block 1 has an opening inner diameter of 440 mm, which is greater than the maximum block cross-sectional dimension in the split cylinder body assembly 2, the large end head connecting block 1 is bagged and vacuumized to-0.09 MPa, and the pressure drop within 10 min is not more than 5 kPa, thereby meeting the air tightness requirement.

[0067] The split cylinder body assembly 2 is spliced by nine blocks, the blocks are thin skin long strips, and the cap-shaped reinforcing rib 7 exists in the interior along the length direction of the storage tank, each block is provided with a connecting flange around, and through holes and a supporting plate nut are sequentially arranged on the flange, so as to connect adjacent blocks, the large head cylinder segment connecting ring 5 and the small head cylinder segment connecting ring 4. The maximum block cross-sectional dimension of the split cylinder body assembly 2 is 424 mm, which is less than the opening size of the large end head connecting block 1, so that the split cylinder body assembly 2 can be firstly demoulded along the radial direction, the two side flanges have a positive 10° demoulding angle, and the remaining blocks are sequentially pressed flange design.

[0068] The small end head connecting block 3 is used for connecting the small head cylinder segment connecting ring 6 and the flange connecting block 4, and together forms a forming support of a small end head region of the storage tank, the small end head connecting block 3 is bagged and vacuumized to-0.09 MPa, and the pressure drop within 10 min is not more than 5 kPa, thereby meeting the air tightness requirement.

[0069] The flange connecting block 4 is located at the two ends of the die, is used for connecting the large end head connecting block 1 and the small end head connecting block 3 with a rotating rod or a supporting rod and other transmission systems respectively during automatic fiber laying, and can be connected with a port cover and a conversion joint after the forming of the storage tank is completed.

[0070] The large end head connecting ring 5 is a circular ring with a similar "L" type cross section, which is used to connect the large end head connecting block 1 and each block of the split cylinder assembly 2. The outer side is provided with a supporting plate nut, and each block of the split cylinder assembly is mechanically connected in turn through a screw. The connection area has a 3° draft angle, which can make the blocks of the split cylinder assembly 2 centripetal demolding.

[0071] The small end head connecting ring 6 is a circular ring with a similar "L" type cross section, which is used to connect the small end head connecting block 3 and each block of the split cylinder assembly 2. The outer side is provided with a supporting plate nut, and each block of the split cylinder assembly is mechanically connected in turn through a screw. The connection area has a 3° draft angle, which can make the blocks of the split cylinder assembly 2 centripetal demolding.

[0072] The cap-shaped reinforcing rib 7 is a reinforcing structure of the block in the split cylinder assembly 2, which is composed of a T700 grade carbon fiber reinforced high temperature epoxy resin composite material skin and a PMI foam core.

[0073] The embodiment also discloses a manufacturing method of the composite material storage tank forming die, which comprises the following steps:

[0074] 1. Forming of the large end head connecting block 1 and the small end head connecting block 3: a metal negative mold is used, unidirectional prepreg is pasted to the corresponding position of the surface of the metal negative mold according to the layering sequence (0 / +45 / 90 / -45 / -45 / 90 / +45 / 0)3, vacuum bag packaging is performed, hot press tank 0.6MPa curing forming is performed, and after demolding, a five-axis machining center is used to machine the surface of the fitting area of the large end head connecting ring, thereby obtaining the large end head connecting block 1 and the small end head connecting block 3 respectively.

[0075] 2. Forming of the block of the split cylinder assembly 2: a metal negative mold is used, unidirectional prepreg is pasted to the corresponding position of the surface of the mold according to the layering sequence (0 / +45 / 0 / -45 / 90 / -45 / 0 / +45 / 0)2, vacuum bag packaging is performed, hot press tank 0.6MPa curing forming is performed, and after demolding, the block blank is obtained, 100 mesh sandpaper is used to polish the inner surface to be rough, and after cleaning, the block blank is reserved.

[0076] 3. Forming of the cap-shaped reinforcing rib 7: the block blank in step 2 is fixed on the mold, a medium temperature curing epoxy film is pasted to the fitting surface of the cap-shaped reinforcing rib, a foam core with a corresponding shape is placed in a corresponding position, the foam is selected to be PMI foam with a compressive strength of 3.2MPa, unidirectional prepreg is pasted on the surface according to the layering sequence [0 / +45 / 0 / 0 / -45 / 0 / 0 / -45 / 0 / 0 / +45 / 0], vacuum bag whole packaging is performed, hot press tank 0.4MPa curing forming is performed, and after demolding and shaping, the split cylinder assembly block with the cap-shaped reinforcing rib 7 is obtained.

[0077] 4. According to steps 2 and 3, all the required segments of the split barrel assembly 2 and the hat-shaped reinforcement ribs 7 are formed and set aside.

[0078] 5. Assemble the split-type barrel assembly 2 in blocks: Punch the M5 support plate nut mounting holes and screw mounting holes on the blocks formed in step 4, with a nail spacing of 25 mm. Install the support plate nuts in the corresponding positions. According to the assembly sequence, mechanically connect all the blocks together with M5 screws to form the split-type barrel assembly 2. The gap after the split-type barrel assembly 2 is assembled is 0 to 0.08 mm, and the step difference between the blocks is less than 0.1 mm.

[0079] 6. Molding of the large head barrel section connecting ring 5 and the small head barrel section connecting ring 6: Use a metal positive mold to lay the unidirectional prepreg in the order of (0 / +45 / 90 / -45 / -45 / 90 / +45 / 0)3 to the corresponding position of the mold surface. After vacuum bag packaging, it is cured and formed in an autoclave at 0.6MPa. After demoulding, use a five-axis machining center to machine the surface of the fitting area with the large and small end head connection blocks. The tolerance of the fitting surface after machining is (-0.25, -0.1)mm. The large head barrel section connecting ring 5 and the small head barrel section connecting ring 6 are obtained respectively, and they are fixed to the corresponding positions of the split barrel assembly 2 assembled in step 5, and M5 screw holes and support plate nut mounting holes are punched out. Remove the large head barrel section connecting ring 5 and the small head barrel section connecting ring 6, and install the corresponding support plate nuts.

[0080] 7. Bond the large head barrel section connecting ring 5 to the large end head connecting block 1, and the small head barrel section connecting ring 6 to the small end head connecting block 3: Clean the fitting surfaces of the head barrel section connecting ring and the large and small end head connecting blocks, apply room temperature curing epoxy paste glue, and bond the large head barrel section connecting ring 5 to the large end head connecting block 1, and the small head barrel section connecting ring 6 to the small end head connecting block 3 respectively. The thickness of the glue layer should be controlled at 0.1-0.2mm, fillet and seal the corners, and let it stand at room temperature for 48 hours to cure.

[0081] 8. Assemble the split-type barrel assembly 2 with the large-end head connection block 1 and the small-end head connection block 3: Fix the split-type barrel assembly 2 assembled in step 5 with a bracket, fix the large-end head connection block 1 and the small-end head connection block 3 cured in step 7 to the large and small ends of the split-type barrel assembly 2 respectively, and use M5 screws to connect the split-type barrel assembly 2 with the large-end head barrel section connection ring 5 and the small-end head barrel section connection ring 6. After the split-type barrel assembly 2 is assembled with the large-end head connection block 1 and the small-end head connection block 3, the gap is 0-0.08mm, and the sinking depth of the large-end head connection block 1 and the small-end head connection block 3 relative to the split-type barrel assembly 2 is (-0.5, -0.1)mm.

[0082] 9. Installing flange connecting block 4: install metal flange connecting block 4 on the corresponding position of large end head connecting block 1 and small end head connecting block 3 through M8 screw, and install it on the corresponding position of winding machine or automatic fiber placement machine transmission device as a whole to obtain a composite material forming die.

[0083] Although the present application has been disclosed with examples as above, it is not intended to limit the present application, and any appropriate modification or equivalent replacement made by those skilled in the art to the technical solutions of the present application shall be covered within the protection scope of the present application, and the protection scope of the present application is defined by the claims.

Claims

1. A composite material tank forming mold, characterized in that: It includes a large end head connection block, a split-flap shell assembly, a small end head connection block, a flange connection block, a large end head shell section connection ring, a small end head shell section connection ring and a hat-shaped reinforcement rib; The flange connection blocks are located at both ends of the forming mold; The outer edge of the large end head connection block is connected to the large end head cylinder section connection ring, and the inner edge is connected to the flange connection block, together forming a forming support for the large end head area of ​​the tank; The outer edge of the small end head connection block is connected to the small end head barrel section connection ring, and the inner edge is connected to the flange connection block, together forming a forming support for the small end head area of ​​the tank; The split barrel assembly is composed of several blocks. The blocks are thin-skinned and long strips, and there are hat-shaped reinforcement ribs inside along the length of the tank. The split barrel assembly is located between the large head barrel segment connecting ring and the small head barrel segment connecting ring. The head end of each block of the split barrel assembly is connected to the large head barrel segment connecting ring, and the tail end is connected to the small head barrel segment connecting ring. The connection and assembly between the mold petal block and the core mold does not rely on metal connecting rods, but is entirely supported by the head barrel section connecting ring and the head connecting block; after the product is formed, the large end head connecting block and the small end head connecting block remain in the product as part of the product head.

2. The molding die according to claim 1, wherein: A support plate nut is provided on the outside of the large head barrel section connecting ring, and the various blocks of the split barrel body assembly are mechanically connected in sequence by screws, and a draft angle is left in the connection area; a support plate nut is provided on the outside of the small head barrel section connecting ring, and the various blocks of the split barrel body assembly are mechanically connected in sequence by screws, and a draft angle is left in the connection area.

3. The molding die according to claim 1, wherein: Each segment of the split barrel assembly is provided with connecting flanges around it, and through holes and support plate nuts are sequentially provided on the flanges to connect adjacent segments and the large head barrel segment connecting ring and the small head barrel segment connecting ring.

4. The molding die according to claim 1, wherein: The main material of the forming mold is fiber-reinforced resin-based composite material, the fiber is continuous carbon fiber, and the resin is high-temperature curing epoxy resin or bismaleimide resin; the component materials of the cap-shaped reinforcement are carbon fiber composite material skin and PMI foam sandwich.

5. A method for manufacturing a composite material tank forming mold according to claim 1, characterized in that: The following steps are involved: 1) Using a metal negative mold, unidirectional prepreg is laid in order to the corresponding position of the metal negative mold surface. After vacuum bag packaging, it is cured in an autoclave. After demoulding, the surface of the area where it fits with the connecting rings of the large and small head barrel sections is machined to obtain the large end head connection block and the small end head connection block respectively; 2) Using a metal female mold, lay the unidirectional prepreg in the order of layering to the corresponding position of the mold surface. After vacuum bagging, it is cured in an autoclave. After demoulding, the split barrel component is obtained. The inner surface is polished with sandpaper to a rough surface, cleaned and set aside. 3) The block blank is fixed on the mold, and a film is laid on the surface where it contacts the hat-shaped reinforcement. The foam sandwich core machined into the corresponding shape is placed in the corresponding position. The unidirectional prepreg is laid on the surface according to the lay-up order. The whole is vacuum-bag-encapsulated and cured in an autoclave. After demolding and reshaping, the split-type barrel component with hat-shaped reinforcement is obtained; 4) Punch the support plate nut mounting holes and screw mounting holes on the obtained blocks, install the support plate nuts in the corresponding positions, and mechanically connect all the blocks together with screws in accordance with the assembly sequence to form a split-type cylinder assembly; 5) Using a metal male mold, lay the unidirectional prepreg in the order of layering to the corresponding position of the mold surface. After vacuum bag packaging, autoclave curing and molding, after demoulding, the surface of the bonding area between the large and small end head connection blocks is machined to obtain the large head barrel segment connection ring and the small head barrel segment connection ring respectively. Fix them to the corresponding positions of the assembled split-type barrel assembly, punch out the screw holes and the support plate nut installation holes, remove the large and small head barrel segment connection rings, and install the corresponding support plate nuts; 6) Clean the fitting surfaces of the large and small head barrel section connecting rings and the large and small end head connecting blocks, apply paste glue, and bond the large head barrel section connecting ring to the large end head connecting block, and the small head barrel section connecting ring to the small end head connecting block, fillet and seal the corners, and let them stand at room temperature to solidify; 7) Fix the split-type barrel assembly with a bracket, fix the solidified large and small end head connection blocks to the large and small ends of the split-type barrel assembly respectively, and use screws to connect the split-type barrel assembly with the large and small head barrel section connection rings; 8) Install the metal flange connection block on the corresponding positions of the large and small end head connection blocks by screws to obtain the composite material tank forming mold.

6. The manufacturing method according to claim 5, wherein: The ply pattern in step 1) is (0 / +45 / 90 / -45 / -45 / 90 / +45 / 0) n , where n is a positive integer according to the shape and requirements of the storage tank product; In step 2), the ply pattern of the split barrel assembly is (0 / +45 / 0 / -45 / 90 / -45 / 0 / +45 / 0) n , where n is a positive integer according to the shape and requirements of the storage tank product; Step 5) The layup pattern of the connecting rings of the medium, large, and small head tube sections is (0 / +45 / 90 / -45 / -45 / 90 / +45 / 0) n Where n is a positive integer according to the shape and requirements of the tank product, and the tolerance range of the fitting surface after machining is controlled within the range of (-0.3, -0.1) mm.

7. The manufacturing method according to claim 5, wherein: In step 3), the foam selected is PMI foam with a compressive strength greater than 2.2 MPa, and the prepreg is selected to be laid alternately at 0° and ±45°, of which 0° accounts for no less than 60%.

8. The manufacturing method according to claim 5, wherein: In step 4), the gap between the petal-type barrel assembly after assembly is less than 0.1 mm, and the step difference between the petal-type barrel assembly is less than 0.1 mm.

9. The manufacturing method according to claim 5, wherein: In step 6), room temperature curing paste structural adhesive is selected for bonding, with a thickness of 0.1-0.2 mm and a room temperature curing time of not less than 24 hours.

10. The manufacturing method according to claim 5, wherein: In step 7), the gap between the split-type barrel assembly and the large and small end head connection blocks after assembly shall not exceed 0.1 mm. The large and small end head connection blocks shall not be higher than the split-type barrel assembly, and the sinking depth shall be within the range of (-0.5, 0) mm.

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