Composite material circumferential corrugated cylindrical shell self-fastening forming mold and preparation method thereof

Abstract

The invention discloses a self-fastening forming die for a composite annular corrugated cylindrical shell and a preparation method of the self-fastening forming die. The invention aims to solve the problems that the circumferential corrugated cylindrical shell made of the composite material cannot be manufactured by using a winding process, however, in an existing mold pressing scheme, sheet-shaped wrinkles are easily extruded at a mold closing seam due to the large thickness of a prepreg before curing, and enough pressure is difficult to apply to the prepreg only through bolt fastening. An inner cylindrical mold, an outer cylindrical mold, an upper clamp, a lower clamp and a positioning disc are adopted, and the composite material circumferential corrugated cylindrical shell is prepared after hot-pressing curing. The mold is reasonable in design, simple in structure, convenient to assemble and disassemble and high in reusability, and the forming quality of the annular corrugated cylindrical shell is guaranteed through cooperation of the positioning disc, the inner cylinder and the outer cylinder. And through the four-section design of the outer cylindrical mold, the problem that prepreg is easily extruded from a mold closing seam during mold closing of the annular corrugated cylindrical shell is solved.

Description

Technical Field

[0001] The invention belongs to the field of organic chemical industry, and in particular relates to a composite material annular corrugated cylindrical shell self-tightening forming die and a preparation method thereof. Background Art

[0002] Submersibles are important equipment for ocean exploration and deep-sea scientific research. As an important part of submersibles, pressure-resistant equipment plays a role in ensuring the normal operation of internal equipment and the health and safety of personnel during diving. As the diving depth of submersibles continues to increase, new requirements are constantly being put forward for the design methods, material properties, and manufacturing process research of the shell. How to further improve the bearing capacity of the pressure shell and achieve the goal of lightweighting has become a hot topic for scholars.

[0003] Composite pressure tank hulls have been used in the manufacture of underwater pressure tank hulls due to their advantages such as low density, high strength, high modulus and designability, achieving the goal of lightweighting, increasing effective load and improving endurance.

[0004] The mechanical properties of the traditional cylindrical pressure shell are poor, while the composite sandwich structure has a larger section inertia moment than a single thin-walled shell due to the multi-layer combination of face-core-face. At the same time, compared with other sandwich structures, the corrugated sandwich has the advantages of large porosity, large load-to-mass ratio, high load-bearing efficiency, strong designability and easy preparation, and has gradually become the focus of attention. Summary of the invention

[0005] The purpose of the present invention is to.

[0006] A composite material annular corrugated cylindrical shell self-tightening forming mold, the composite material annular corrugated cylindrical shell is a composite material annular corrugated cylindrical shell formed by a rotating body of trapezoidal corrugations; the composite material annular corrugated cylindrical shell is a one-time forming mold, including: an inner cylindrical mold, an outer cylindrical mold, a clamp and a positioning plate; the inner cylindrical mold includes 2 inner cylindrical priority arc surface petals and 4 inner cylindrical non-priority arc surface petals alternately arranged and assembled along the circumferential direction, and the two ends of the inner cylindrical mold are connected to the positioning plate; the outer cylindrical mold is sleeved outside the inner cylindrical mold, including 2 outer cylindrical priority arc surface petals and 2 outer cylindrical non-priority arc surface petals Arrange and assemble in sequence along the circumferential direction; the central angle corresponding to the outer cylindrical non-priority arc surface petal is 15°~40°, and the contact surface between the outer cylindrical priority arc surface petal and the outer cylindrical non-priority arc surface petal is deflected 35°~55° compared with the intersection of the central angle cutting line and the thickness mid-plane as the center point; the two ends of the two outer cylindrical non-priority arc surface petals are fixed by positioning plates or each two adjacent arc surface petals are pressed by two adjacent contact surfaces, and then pre-tightened and fixed into an integrated structure through the bolt holes on the outside of the two outer cylindrical priority arc surface petals; clamps are installed on the outer surfaces of the two outer cylindrical priority arc surface petals.

[0007] Furthermore, the inner cylindrical mold is a split-petal hollow cylinder, which is assembled alternately along the circumferential direction in the order of 1 inner cylindrical priority arc surface petal, 2 inner cylindrical non-priority arc surface petals, 1 inner cylindrical priority arc surface petal, and 2 inner cylindrical non-priority arc surface petals; the 6 arc surface petals are evenly divided according to the thickness mid-surface, with a central angle of 60°, and the contact surface between the inner cylindrical priority arc surface petal and the inner cylindrical non-priority arc surface petal is deflected 35° to 55° from the intersection of the central angle cutting line and the thickness mid-surface as the center point, and the two ends are fixedly connected by positioning plates for demolding.

[0008] Furthermore, the outer surface of the inner cylindrical mold is a corrugated structure with uniform convex and concave curved surfaces along its radial direction, and the shape of the inner wall of the outer cylindrical mold is symmetrical to the shape of the outer surface of the inner cylindrical mold.

[0009] Furthermore, the thickness of the outer surface of the inner and outer cylindrical molds excluding the corrugation height cannot be less than 15 mm to avoid deformation of the mold due to pressure applied during the manufacturing process.

[0010] Furthermore, each two adjacent circular arc surface petals of the outer cylindrical mold are pressed together by two adjacent contact surfaces to avoid extrusion of sheet-like prepreg at the joint to form wrinkles.

[0011] Furthermore, the positioning plate is detachable.

[0012] Furthermore, grippers are installed at both ends of the clamp, and auxiliary leveling blocks are installed on both sides, so that the upper and lower surfaces of the clamp are level when it is placed.

[0013] Furthermore, a gap is left between the inner cylindrical mold and the outer cylindrical mold for laying prepreg.

[0014] A method for preparing a composite material annular corrugated cylindrical shell self-tightening forming mold, the specific steps are as follows:

[0015] 1) Inner cylinder mold assembly: Alternately arrange and assemble along the circumference in the order of 1 inner cylinder priority arc surface petal, 2 inner cylinder non-priority arc surface petals, 1 inner cylinder priority arc surface petal, and 2 inner cylinder non-priority arc surface petals; both ends are fixedly connected to the positioning plate through the inner cylinder bolts and their bolt holes;

[0016] 2) Preheat the inner cylindrical mold to 70°C and apply a release agent after preheating;

[0017] 3) Material selection: The composite material is T700 carbon fiber reinforced composite prepreg;

[0018] 4) Laying prepreg: Cut the prepreg according to the size, lay it layer by layer according to the laying angle, and lay it outside the inner cylindrical mold;

[0019] 5) Assemble the cylindrical mold as a whole: put the assembled inner cylindrical mold together with the laid prepreg into the outer cylindrical priority arc surface petal, and then assemble the two outer cylindrical non-priority arc surface petals and another outer cylindrical priority arc surface petal in sequence; the two ends of the two outer cylindrical non-priority arc surface petals are fixedly connected by positioning plates or compacted and tightened by the subsequent two outer cylindrical priority arc surface petals, and finally the assembled mold is pre-tightened and fixed into an integrated structure through the bolt holes on the outside of the two outer cylindrical priority arc surface petals;

[0020] 6) Place the upper and lower fixtures: Place the lower fixture on a horizontal plane, and then place the assembled cylindrical mold as a whole on the lower fixture. The lower fixture, the positioning plate, and the outer cylindrical priority arc surface are divided into petals to form a groove for assembly; assemble the upper fixture in the same way;

[0021] 7) Curing treatment: Place the whole mold on the vulcanizer, apply 2MPa pressure, set the preheating temperature to 80℃-100℃ for 30 minutes, then adjust to 120℃ and keep for 90-120 minutes;

[0022] 8) Demolding: After natural cooling, remove the upper clamps one by one, the two outer cylindrical priority arc surface petals and the outer cylindrical non-priority arc surface petals, remove the bolts at both ends, first remove the inner cylindrical priority arc surface petals, and finally remove the inner cylindrical non-priority arc surface petals in turn.

[0023] The beneficial effects of the present invention are:

[0024] (1) The two end covers in the present invention are provided to fix the basic structure of the core column from the top and bottom surfaces of the inner core column respectively; the inner cylindrical mold is composed of a plurality of inner cylindrical priority arc surface petals and inner cylindrical non-priority arc surface petals, which are arranged alternately along the circumferential direction in sequence to facilitate demolding; the outer cylindrical mold pressurizes the prepreg. At the same time, the four-petal design of the outer cylindrical mold solves the problem that the prepreg is easily squeezed out from the mold seam when the annular corrugated cylindrical shell is molded; the upper and lower clamps fix the mold and transfer heat at the same time; the auxiliary horizontal blocks on both sides of the clamp make the upper and lower surfaces of the clamp level when assembling the mold to ensure uniform pressure;

[0025] (2) The present invention uses a vulcanizer to apply pressure and heat, which can reduce process defects caused by the difficulty in applying sufficient pressure to the prepreg by bolt tightening alone;

[0026] (3) The composite annular corrugated cylindrical shell has an undulating corrugated structure, which makes it difficult to implement the fiber winding step. The composite annular corrugated cylindrical shell prepared by the molding method of the vulcanizer of the present invention can be subsequently connected with the panel by gluing to form a fully composite annular corrugated sandwich cylindrical shell;

[0027] (4) The process of the present invention is simple to implement, easy to operate and highly flexible. A corrugated cylindrical shell thinner than the reserved gap can be prepared by adding release paper or a high-temperature resistant silicone sheet between the inner cylindrical mold and the outer cylindrical mold. In addition, the magnitude of the force applied by the outer cylinder non-priority arc surface petal to the composite carbon fiber cylindrical shell can be controlled by designing the angle between the outer cylinder priority arc surface petal and the contact surface of the outer cylinder non-priority arc surface petal in advance.

[0028] (5) The carbon fiber composite annular corrugated cylindrical shell prepared by the present invention is an intermediate step in manufacturing a composite carbon fiber annular corrugated sandwich pressure shell structure. The manufactured carbon fiber composite annular corrugated cylindrical shell has a high annular bending stiffness after being bonded to the carbon fiber composite cylindrical shell by adhesive film, which can effectively improve the anti-buckling performance of the composite material structure to achieve the goal of lightweight design.

[0029] (6) The present invention has low manufacturing cost and can be mass-produced. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the assembly of the three-dimensional structure of the present invention;

[0031] Figure 2 This is a schematic diagram of the structure of the mold of the present invention after assembly without the positioning plate;

[0032] Figure 3 Divide the non-priority arc surface of the inner cylinder into petals;

[0033] Figure 4 Divide the inner cylinder into petals with priority arc surface;

[0034] Figure 5 It is a combined diagram of the non-priority arc surface petals and the priority arc surface petals of the inner cylinder;

[0035] Figure 6 It is an internal cylindrical bolt;

[0036] Figure 7 Divide the outer cylinder into petals with priority arc surface;

[0037] Figure 8 Divide the non-priority arc surface of the outer cylinder into petals;

[0038] Fig. 9 It is an external cylindrical bolt;

[0039] Fig.10 For upper and lower clamps;

[0040] Fig.11 For positioning plate.

[0041] In the figure: inner cylinder non-priority arc surface petal 1, inner cylinder bolt hole 2, inner cylinder priority arc surface petal 3, inner cylinder bolt 4, outer cylinder priority arc surface petal bolt hole 5, outer cylinder priority arc surface petal 6, outer cylinder non-priority arc surface petal 7, outer cylinder non-priority arc surface petal bolt hole 8, upper and lower clamps 9, gripper 10, auxiliary horizontal block 11, positioning plate 12, outer cylinder bolt 13. DETAILED DESCRIPTION

[0042] The present invention will be further described below in conjunction with the accompanying drawings.

[0043] Combination Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Fig.11The present invention discloses a composite material annular corrugated cylindrical shell self-tightening forming mold, wherein the composite material annular corrugated cylindrical shell is a composite material annular corrugated cylindrical shell formed by a rotating body of trapezoidal corrugations; the composite material annular corrugated cylindrical shell is a one-time forming mold, comprising: an inner cylindrical mold, an outer cylindrical mold, a clamp 9 and a positioning plate 12; the inner cylindrical mold comprises two inner cylindrical priority arc surface petals 3 and four inner cylindrical non-priority arc surface petals 1 which are alternately arranged and assembled along the circumferential direction, and the two ends of the inner cylindrical mold are connected to the positioning plate 12; the inner cylindrical mold is a petal-type hollow cylinder, according to 1 The inner cylinder priority arc surface petals 3, 2 inner cylinder non-priority arc surface petals 1, 1 inner cylinder priority arc surface petal 3, and 2 inner cylinder non-priority arc surface petals 1 are alternately arranged and assembled along the circumferential direction in the order; the 6 arc surface petals are evenly divided according to the thickness mid-plane, and the central angle is 60°. The contact surface between the inner cylinder priority arc surface petal 3 and the inner cylinder non-priority arc surface petal 1 is deflected 35° to 55° from the intersection of the central angle cutting line and the thickness mid-plane as the center point, and the two ends are fixedly connected to the positioning plate 12 through the inner cylinder bolt hole 2 and the inner cylinder bolt 4 for demoulding. The outer cylindrical mold is mounted outside the inner cylindrical mold, and includes two outer cylindrical priority arc surface petals 6 and two outer cylindrical non-priority arc surface petals 7, which are sequentially arranged and assembled along the circumferential direction; the center angle corresponding to the outer cylindrical non-priority arc surface petals 7 is 15° to 40°, and the contact surface between the outer cylindrical priority arc surface petals 6 and the outer cylindrical non-priority arc surface petals 7 is deflected by 35° to 55° from the intersection of the center angle cutting line and the thickness mid-surface as the center point; the two ends of the two outer cylindrical non-priority arc surface petals 7 are fixed to the positioning plate 12 through the outer cylindrical non-priority arc surface petal bolt holes 8 and the outer cylindrical bolts 13, or each adjacent two arc surface petals are pressed by two adjacent contact surfaces, and then the bolt holes 5 outside the two outer cylindrical priority arc surface petals 6 are pre-tightened and fixed into an integrated structure. A clamp 9 is installed on the outer surface of the two outer cylindrical priority arc surface petals 6. Complete the assembly of the entire device.

[0044] The present invention provides a method for preparing a composite material annular corrugated cylindrical shell self-tightening forming die, which specifically comprises:

[0045] Step 1: Assemble the inner cylindrical mold; Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Fig.11 As shown;

[0046] Step 2: Place the inner cylindrical mold in an oven for preheating at 80°C, and then apply a release agent to the mold surface; Figure 1 , Figure 2 As shown;

[0047] Step 3: Laying prepreg: Cut the prepreg according to the size, lay it layer by layer according to the laying angle, and lay it outside the assembled inner cylindrical mold; Figure 1 , Figure 2 As shown;

[0048] Step 4: The assembled inner cylindrical mold together with the laid prepreg is placed in the outer cylindrical priority arc surface petal 6, and then the two outer cylindrical non-priority arc surface petals 7 and another outer cylindrical priority arc surface petal 6 are assembled in sequence. The two ends of the two outer cylindrical non-priority arc surface petals 7 can be fixedly connected by the positioning plate 12 or can be compacted and fastened through the outer cylindrical priority arc surface petal bolt holes 5 on the outer sides of the two subsequent outer cylindrical priority arc surface petals 6. Finally, the assembled mold is pre-tightened and fixed as a whole through the outer cylindrical priority arc surface petal bolt holes 5 on the outer sides of the two outer cylindrical priority arc surface petals 6; Figure 1 , Figure 2 , Figure 7 , Figure 8 , Fig. 9 , Fig.11 shown.

[0049] Step 5: Place the lower fixture 9 on a horizontal plane, and then place the assembled cylindrical mold as a whole on the lower fixture 9. The lower fixture 9 is assembled with the positioning plate 12 and the groove formed by the outer cylindrical priority arc surface petal 6. The upper fixture 9 is assembled in the same way; Figure 1 , Figure 2 , Fig.10 , Fig.11 shown.

[0050] Step 6: Place the whole mold on the vulcanizer, apply 2MPa pressure, preheat at 90℃ for 30 minutes, then adjust to 120℃ and keep for 90-120 minutes; Figure 1 , Figure 2 shown.

[0051] Step 7: After natural cooling, remove the upper fixture 9, the outer cylindrical priority arc surface petal 6 and the outer cylindrical non-priority arc surface petal 7 one by one, remove the bolts at both ends, first remove the inner cylindrical priority arc surface petal 3, and then remove the remaining petals in turn; Figure 1 , Figure 2 shown.

[0052] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A composite material annular corrugated cylindrical shell self-tightening forming die, characterized in that: The composite annular corrugated cylindrical shell is a composite annular corrugated cylindrical shell formed by a rotating body of trapezoidal corrugations; the composite annular corrugated cylindrical shell is a one-time forming mold, comprising: an inner cylindrical mold, an outer cylindrical mold, a clamp (9) and a positioning plate (12); the inner cylindrical mold comprises two inner cylindrical priority arc surface petals (3) and four inner cylindrical non-priority arc surface petals (1) which are alternately arranged and assembled along the circumferential direction, and the two ends of the inner cylindrical mold are connected to the positioning plate (12); the outer cylindrical mold is sleeved outside the inner cylindrical mold, and comprises two outer cylindrical priority arc surface petals (6) and two outer cylindrical non-priority arc surface petals (7) which are sequentially arranged and assembled along the circumferential direction; The center angle of the outer cylindrical non-priority arc surface petal (7) is 15° to 40°, and the contact surface between the outer cylindrical priority arc surface petal (6) and the outer cylindrical non-priority arc surface petal (7) is deflected by 35° to 55° relative to the intersection of the center angle cutting line and the thickness mid-plane as the center point; the two ends of the two outer cylindrical non-priority arc surface petals (7) are fixed by a positioning plate (12) or each adjacent two arc surface petals are pressed by two adjacent contact surfaces, and then the bolt holes (5) on the outside of the two outer cylindrical priority arc surface petals (6) are pre-tightened and fixed into an integrated structure; and the outer surfaces of the two outer cylindrical priority arc surface petals (6) are both installed with clamps (9).

2. A composite material annular corrugated cylindrical shell self-tightening forming mold according to claim 1, characterized in that: The inner cylindrical mold is a split-flap hollow cylinder, which is alternately arranged and assembled along the circumference in the order of one inner cylindrical priority arc surface flap (3), two inner cylindrical non-priority arc surface flaps (1), one inner cylindrical priority arc surface flap (3), and two inner cylindrical non-priority arc surface flaps (1); the six arc surface flaps are evenly divided according to the thickness mid-plane, and the center angle is 60°. The contact surface between the inner cylindrical priority arc surface flap (3) and the inner cylindrical non-priority arc surface flap (1) is deflected by 35° to 55° relative to the intersection of the center angle cutting line and the thickness mid-plane, and the two ends are fixedly connected by a positioning plate for demoulding.

3. A composite material annular corrugated cylindrical shell self-tightening forming die according to claim 1, characterized in that: The outer surface of the inner cylindrical mold is a corrugated structure with uniform convex and concave curved surfaces along its radial direction, and the shape of the inner wall of the outer cylindrical mold is symmetrical to the shape of the outer surface of the inner cylindrical mold.

4. A composite material annular corrugated cylindrical shell self-tightening forming die according to claim 3, characterized in that: The thickness of the outer surface of the inner and outer cylindrical molds excluding the corrugation height cannot be less than 15 mm to avoid deformation of the mold due to pressure applied during the manufacturing process.

5. The composite material annular corrugated cylindrical shell self-tightening forming mold according to claim 1, characterized in that: The two adjacent circular arc surface petals of the outer cylindrical mold are pressed together by two adjacent contact surfaces to avoid the sheet-like prepreg being squeezed out at the joint to form wrinkles.

6. The composite material annular corrugated cylindrical shell self-tightening forming mold according to claim 1, characterized in that: The fixed plate (12) is detachable.

7. The composite material annular corrugated cylindrical shell self-tightening forming mold according to claim 1, characterized in that: Grippers (10) are installed at both ends of the clamp (9), and auxiliary leveling blocks are installed on both sides so that the upper and lower surfaces of the clamp (9) are level when placed.

8. The composite material annular corrugated cylindrical shell self-tightening forming mold according to claim 1, characterized in that: A gap is left between the inner cylindrical mold and the outer cylindrical mold for laying prepreg.

9. A method for preparing a composite material annular corrugated cylindrical shell self-tightening forming mold according to any one of claims 1 to 8, characterized in that: The specific steps are as follows: 1) Assembling the inner cylindrical mold: arranging and assembling the inner cylindrical mold in an alternating manner along the circumference in the order of one inner cylindrical preferred arc surface petal (3), two inner cylindrical non-preferred arc surface petals (1), one inner cylindrical preferred arc surface petal (3), and two inner cylindrical non-preferred arc surface petals (1); the two ends are fixedly connected to the positioning plate (12) through the inner cylindrical bolts (4) and the bolt holes (2) thereof; 2) Preheat the inner cylindrical mold to 70°C and apply a release agent after preheating; 3) Material selection: The composite material is T700 carbon fiber reinforced composite prepreg; 4) Laying prepreg: Cut the prepreg according to the size, lay it layer by layer according to the laying angle, and lay it outside the inner cylindrical mold; 5) Assembling the cylindrical mold as a whole: the assembled inner cylindrical mold together with the laid prepreg is placed in the outer cylindrical priority arc surface petal (6), and then the two outer cylindrical non-priority arc surface petals (7) and another outer cylindrical priority arc surface petal (6) are assembled in sequence; wherein the two ends of the two outer cylindrical non-priority arc surface petals (7) are fixedly connected by a positioning plate (12) or compacted and tightened by the subsequent two outer cylindrical priority arc surface petals (6), and finally the assembled mold is pre-tightened and fixed into an integrated structure through the bolt holes (5) on the outside of the two outer cylindrical priority arc surface petals (6); 6) Placing the upper and lower fixtures (9): placing the lower fixture (9) on a horizontal plane, and then placing the assembled cylindrical mold as a whole on the lower fixture (9), the lower fixture (9) and the positioning plate (12) and the outer cylindrical priority arc surface petal (6) form a groove assembly; assemble the upper fixture (9) in the same way; 7) Curing treatment: Place the whole mold on the vulcanizer, apply 2MPa pressure, set the preheating temperature to 80℃-100℃ for 30 minutes, then adjust to 120℃ and keep for 90-120 minutes; 8) Demolding: After natural cooling, remove the upper clamp (9), the two outer cylindrical priority arc surface petals (6) and the outer cylindrical non-priority arc surface petals (7) one by one, remove the bolts at both ends, first remove the inner cylindrical priority arc surface petals (3), and finally remove the inner cylindrical non-priority arc surface petals (1) in turn.

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