Ribbed composite skirt structure and preparation method thereof

Abstract

The invention provides a reinforced composite skirt structure and a preparation method, and relates to the technical field of rocket engines, the reinforced composite skirt structure comprises a skirt body, the skirt body is composed of a skirt flange and a skirt side wall, and the skirt side wall is integrally connected to the outer edge of the skirt flange and extends towards the back face of the skirt flange; the plurality of reinforced blocks are arranged on the back surface of the skirt flange; skirt through holes are formed in the skirt flanges and the reinforced blocks in a penetrating mode, and threaded sleeves are fixedly arranged in the skirt through holes. The skirt body and the reinforced blocks are made of carbon fiber composite materials. Compared with a skirt structure of a traditional rocket engine combustion chamber shell, the skirt structure has the advantages that a metal corner box in the prior art is replaced with the stiffened blocks and the threaded sleeves, the skirt body, the stiffened blocks and the threaded sleeves are integrally made of the carbon fiber composite materials and are fixed through glue joint, the procedure of threaded connection is omitted, and the forming difficulty is greatly reduced. The stiffened blocks can ensure the structural strength and rigidity of the skirt body structure, and the weight of a formed product can be reduced by 15% compared with that of a traditional skirt body.

Description

Technical Field

[0001] The invention relates to the technical field of rocket engines, and in particular to a reinforced composite material skirt structure and a preparation method thereof. Background Art

[0002] Composite materials have been widely used in the manufacture of solid rocket engine combustion chamber casings due to their excellent properties such as low specific gravity, high specific strength and specific modulus.

[0003] The combustion chamber shell is composed of front and rear joints, front and rear skirts, fiber winding layers and inner insulation layers. The front and rear skirts of the existing combustion chamber shell are generally composed of composite skirts and metal corner boxes. The composite skirts and metal corner boxes are fixed by gluing and threading. The metal corner boxes play a role in improving the structural strength and connecting other components. The molding is difficult and cannot fully meet the lightweight requirements of rocket engines.

[0004] In view of this, how to provide a front and rear skirt structure that reduces the difficulty of molding and achieves lightweight rocket engines is an issue that technical personnel in this field urgently need to solve. Summary of the invention

[0005] The purpose of the present invention is to provide a reinforced composite material skirt structure to solve the problems existing in the prior art.

[0006] To achieve the above object, the present invention provides a reinforced composite material skirt structure, comprising:

[0007] A skirt body, consisting of a skirt flange and a skirt side wall, wherein the skirt side wall is integrally connected to the outer edge of the skirt flange and extends toward the back side of the skirt flange;

[0008] A plurality of reinforcing blocks are arranged on the back side of the skirt flange; a skirt through hole is arranged through the skirt flange and the reinforcing blocks, and a screw sleeve is fixedly arranged in the skirt through hole; the skirt body and the reinforcing blocks are made of carbon fiber composite materials.

[0009] Furthermore, the thickness of the skirt side wall increases gradually from a position away from the skirt flange to a position close to the skirt flange, and a plurality of crack-stopping grooves are formed through the inner and outer surfaces of the skirt side wall.

[0010] Furthermore, a plurality of the reinforcement blocks are circumferentially arranged on the back side of the skirt flange, and adjacent reinforcement blocks are connected by connection blocks.

[0011] Furthermore, the reinforcement block is an arc-shaped block, which protrudes toward the skirt side wall and is connected to the inner surface of the skirt side wall.

[0012] Furthermore, the skirt through hole is a stepped hole, and the screw sleeve is adapted to the shape of the skirt through hole and is fixed in the skirt through hole by gluing.

[0013] Furthermore, one end of the screw sleeve is located on the front side of the skirt flange, and one end of the screw sleeve is provided with an internal threaded hole.

[0014] The present invention also provides a method for preparing a reinforced composite material skirt structure, which is used to prepare the reinforced composite material skirt structure, comprising the following steps:

[0015] S1: Prepare a male mold that matches the shape of the skirt and the reinforcement block, and apply a release agent;

[0016] S2: prepreg is cut by automatic cutting machine;

[0017] S3: Manual laying on the positive mold;

[0018] S4: Encapsulate to form a mold, put the mold into an autoclave for curing, the curing pressure is 0.6-0.8MPa, first cure at 130°C for 1h, then cure at 180°C for 3h; cool down to below 60°C and take out of the oven;

[0019] S5: demoulding, removing the reinforced composite skirt structure from the mold;

[0020] S6: Processing the reinforced composite skirt structure by CNC machine tools to form skirt through holes and crack arrest grooves;

[0021] S7: processing the threaded sleeve by a CNC machine tool, and anodizing the threaded sleeve;

[0022] S8: sandblasting the connection surface between the screw sleeve and the skirt through hole;

[0023] S9: Glue the screw sleeve into the skirt through hole with structural adhesive and leave it to cure at room temperature.

[0024] The present invention discloses the following technical effects:

[0025] Compared with the skirt structure of the combustion chamber shell of a traditional rocket engine, the present application replaces the metal corner box in the prior art with a reinforcing block and a screw sleeve, and uses a carbon fiber composite material to form the skirt and the reinforcing block in one piece. The screw sleeve is fixed by gluing, eliminating the process of threaded connection, greatly reducing the difficulty of molding. The reinforcing block can ensure the structural strength and rigidity of the skirt structure, and the weight of the product after molding can be reduced by 15% compared with the traditional skirt. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 It is a schematic diagram of the structure of the present invention;

[0028] Figure 2 It is a cross-sectional schematic diagram of the present invention;

[0029] Among them, 1. skirt body; 101. skirt flange; 102. skirt side wall; 103. crack stop groove; 2. screw sleeve; 201. threaded hole; 202. hexagon socket hole; 3. reinforcement block; 4. connection block. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] An embodiment of the present invention provides a reinforced composite skirt structure, including: a skirt body 1, which is composed of a skirt flange 101 and a skirt side wall 102 to form an L-shaped annular structure, and the skirt side wall 102 is integrally connected to the outer edge of the skirt flange 101 and extends toward the back side of the skirt flange 101; a plurality of reinforcing blocks 3 are arranged on the back side of the skirt flange 101 and are located inside the skirt side wall 102; a skirt through hole is penetrated by the skirt flange 101 and a screw sleeve 2 is fixedly arranged in the skirt through hole, and the screw sleeve 2 is made of metal material; the skirt body 1 and the reinforcing blocks 3 are integrally made of carbon fiber composite material.

[0033] In this embodiment, the thickness of the skirt side wall 102 increases gradually from a position away from the skirt flange 101 to a position close to the skirt flange 101 (non-linearly, just increasing), and a plurality of crack-stop grooves 103 are provided through the inner and outer surfaces of the skirt side wall 102. The purpose of such design is to release stress when installing the skirt body 1.

[0034] In this embodiment, a plurality of reinforcement blocks 3 are circumferentially arranged on the back side of the skirt flange 101 , and adjacent reinforcement blocks 3 are connected via connection blocks 4 .

[0035] In this embodiment, the reinforcing block 3 is an arc-shaped block, the reinforcing block 3 protrudes toward the skirt side wall 102 and is connected to the inner surface of the skirt side wall 102, and the reinforcing block 3 and the connecting block 4 are both set to a suitable thickness. In this embodiment, eight reinforcing blocks 3 are provided, and eight skirt through holes are also provided accordingly, and the position of the skirt through hole is substantially located at the center of the reinforcing block 3.

[0036] In the present embodiment, the skirt through hole is a stepped hole, and the screw sleeve 2 is adapted to the shape of the skirt through hole and fixed in the skirt through hole by gluing. One end of the screw sleeve 2 is located at the front of the skirt flange 101, and one end of the screw sleeve 2 is provided with an internal threaded hole 201, and the internal threaded hole 201 is used to connect other structures of the rocket engine combustion chamber shell. The present embodiment adopts a gluing method to fix the screw sleeve 2, while the traditional "composite skirt and metal corner box" assembly needs to be fixed by gluing and threading. The present embodiment can save the drilling, positioning and other processes required for the threaded connection, and the molding process is greatly simplified. The other end of the screw sleeve 2 is located at the back of the skirt flange 101, and the other end of the screw sleeve 2 is provided with an inner hexagonal hole 202, which is convenient for the installation of the screw sleeve 2.

[0037] The embodiment of the present invention further provides a method for preparing a reinforced composite material skirt structure, which is used to prepare a reinforced composite material skirt structure, comprising the following steps:

[0038] S1: prepare a male mold that matches the shape of the skirt 1 and the reinforcement block 3, clean the dust and impurities on the surface, and apply a release agent after cleaning;

[0039] S2: Prepreg cutting: To ensure the accuracy of the cutting shape and cutting size of the prepreg, the prepreg is cut according to the pre-made electronic cutting drawing and cut by an automatic cutting machine;

[0040] S3: Manually lay the prepreg on the positive mold; manually lay the prepreg on the mold according to the drawing. Before laying each layer, check the surface condition of the prepreg to see if it is complete; when laying, lay, check and record layer by layer. Each layer should be accurate and in place without "bridging", "folding", "air encapsulation" and "introduction of debris". During the laying process, vacuum pre-compaction should be carried out according to the required number of layers;

[0041] S4: Encapsulate to form a mold, use non-porous isolation film, breathable felt and other auxiliary materials for encapsulation, then put the mold into an autoclave for curing, the curing pressure is 0.6-0.8MPa, first cure at 130℃ for 1h, then cure at 180℃ for 3h; cool down to below 60℃ and take out of the oven;

[0042] S5: demoulding, removing the integrally manufactured reinforced composite skirt structure (skirt body 1 and reinforcement block 3) from the mold;

[0043] S6: Processing the reinforced composite skirt structure by a CNC machine tool to form skirt through holes and crack-stop grooves 103;

[0044] S7: Processing a metal bar into a screw sleeve 2 by a CNC machine tool, processing the threaded hole 201, the step shape and the hexagonal hole 202 of the screw sleeve 2 to meet the design requirements according to the drawing, and then anodizing the screw sleeve 2;

[0045] S8: sandblasting the connection surface between the screw sleeve 2 and the skirt through hole;

[0046] S9: Glue the screw sleeve 2 into the skirt through hole using structural adhesive and allow it to cure at room temperature.

[0047] After testing, the weight of the reinforced composite skirt structure prepared in this embodiment is about 47kg, and the weight of the "composite skirt and metal corner box" assembly in the prior art is about 55kg, which can reduce the weight by 15%. The essence of weight reduction is that the reinforced block 3 made of carbon fiber composite material + the screw sleeve 2 made of metal material is lighter than the weight of the metal corner box.

[0048] Axial compression tests were conducted on the "composite skirt and metal corner box" components of the same size and the reinforced composite skirt structure prepared in this embodiment. The results show that the maximum pressure-bearing capacity of the "composite skirt and metal corner box" component is about 320 tons, and the maximum pressure-bearing capacity of the reinforced composite skirt structure is about 400 tons. In other words, this embodiment can improve structural strength and rigidity while reducing weight.

[0049] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0050] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A reinforced composite skirt structure, characterized in that: include: A skirt body (1) is composed of a skirt flange (101) and a skirt side wall (102), wherein the skirt side wall (102) is integrally connected to the outer edge of the skirt flange (101) and extends toward the back side of the skirt flange (101); A plurality of reinforcing blocks (3) are arranged on the back side of the skirt flange (101); a skirt through hole is provided through the skirt flange (101) and the reinforcing blocks (3), and a screw sleeve (2) is fixedly provided in the skirt through hole; the skirt body (1) and the reinforcing blocks (3) are made of carbon fiber composite material.

2. A reinforced composite material skirt structure according to claim 1, characterized in that: The thickness of the skirt side wall (102) increases gradually from a position away from the skirt flange (101) to a position close to the skirt flange (101), and a plurality of crack-stopping grooves (103) are formed through the inner and outer surfaces of the skirt side wall (102).

3. A reinforced composite material skirt structure according to claim 2, characterized in that: A plurality of the reinforcement blocks (3) are arranged on the back side of the skirt flange (101) along the circumferential direction, and adjacent reinforcement blocks (3) are connected via connection blocks (4).

4. A reinforced composite material skirt structure according to claim 3, characterized in that: The reinforcement block (3) is an arc-shaped block, and the reinforcement block (3) protrudes toward the skirt side wall (102) and is connected to the inner surface of the skirt side wall (102).

5. A reinforced composite material skirt structure according to claim 4, characterized in that: The skirt through hole is a stepped hole, and the screw sleeve (2) is adapted to the shape of the skirt through hole and is fixed in the skirt through hole by gluing.

6. A reinforced composite material skirt structure according to claim 5, characterized in that: One end of the screw sleeve (2) is located on the front side of the skirt flange (101), and one end of the screw sleeve (2) is provided with an internal threaded hole (201).

7. A method for preparing a reinforced composite skirt structure, characterized in that: The method for preparing the reinforced composite material skirt structure according to claim 6 comprises the following steps: S1: preparing a male mold that matches the shape of the skirt (1) and the reinforcement block (3), and applying a mold release agent; S2: prepreg is cut by automatic cutting machine; S3: Manual laying on the positive mold; S4: Encapsulate to form a mold, put the mold into an autoclave for curing, the curing pressure is 0.6-0.8MPa, first cure at 130°C for 1h, then cure at 180°C for 3h; cool down to below 60°C and take out of the oven; S5: demoulding, removing the reinforced composite skirt structure from the mold; S6: Processing the reinforced composite skirt structure by a CNC machine tool to form skirt through holes and crack arrest grooves (103); S7: Processing the screw sleeve (2) by a numerical control machine tool, and anodizing the screw sleeve (2); S8: sandblasting the connection surface between the screw sleeve (2) and the skirt through hole; S9: Glue the screw sleeve (2) into the skirt through hole using structural adhesive and allow to cure at room temperature.

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