A composite case for a solid rocket engine and a method of forming the same

Abstract

The present application relates to a kind of composite material shell of solid rocket engine and its forming method.The front shell of comprising by the front head of metal material and front skirt, the rear shell of comprising by the rear head of metal material and rear skirt, front head is connected with front skirt welding, rear head is connected with rear skirt welding, metal material straight cylinder section shell is arranged between front shell and rear shell, the front end of straight cylinder section shell is connected with the rear end of front head welding, the rear end of straight cylinder section shell is fixed with the front end of rear head welding;High-strength carbon fiber high-temperature-resistant modified phenolic resin laminated plate hoop winding shell is arranged on the outside of straight cylinder section shell and is formed by hoop winding, and the both ends of hoop winding shell are covered respectively between front shell and straight cylinder section shell, between straight cylinder section shell and rear shell The shell weld of between.The present application realizes the lightweight design of rocket engine shell and has certain heat protection function, and its production cost does not increase significantly while improving the performance of solid rocket engine.

Description

Technical Field

[0001] This invention belongs to the field of aerospace equipment technology, and in particular relates to a composite material shell for a solid rocket engine and its molding method. Background Technology

[0002] Solid rocket motors are widely used in various aerospace fields due to their advantages such as simple structure, reliable operation, convenient storage, and rapid start-up. In recent years, with the continuous improvement of missile weapon technical specifications, the requirements for lightweight engine design have become increasingly stringent. With the development of composite material technology, composite material shells have been widely used in solid-propellant strategic missiles; however, due to their high cost and poor thermal load resistance, they have not been widely used in tactical weapons. How to achieve lightweight and low-cost solid rocket motor shells has always been a goal pursued by the solid rocket motor field.

[0003] Traditional solid rocket motors have heavy metal casings, which cannot effectively improve the engine's mass-to-weight ratio. Composite material casings have higher specific strength, which can effectively improve the engine's mass-to-weight ratio; however, their high cost and rapid performance degradation at high temperatures limit their application. Therefore, there is a need to develop novel composite material casing technologies for solid rocket motors that can reduce weight and extend range without sacrificing strength, while also meeting thermal protection requirements. Summary of the Invention

[0004] This invention provides a composite material shell for a solid rocket engine that achieves a reasonable structural design, lightweight design, and certain heat protection function to solve the technical problems existing in the prior art, thereby realizing an integrated design of structural heat protection. It comprehensively improves the performance of solid rocket engines without significantly increasing production costs.

[0005] The technical solution adopted by this invention to solve the technical problems existing in the prior art is as follows: A composite material shell for a solid rocket motor includes a front shell composed of a front end cap and a front skirt made of metal, and a rear shell composed of a rear end cap and a rear skirt made of metal. The front end cap and the front skirt are welded together, and the rear end cap and the rear skirt are welded together. A straight cylindrical shell made of metal is provided between the front shell and the rear shell. The front end of the straight cylindrical shell is welded to the rear end of the front end cap, and the rear end of the straight cylindrical shell is welded to the front end of the rear end cap. On the outside of the straight cylindrical shell, a wound shell formed by circumferentially winding a high-strength carbon fiber high-temperature modified phenolic resin laminate is provided, and the two ends of the wound shell respectively cover the shell welds between the front shell and the straight cylindrical shell and between the straight cylindrical shell and the rear shell.

[0006] Preferably, the front end cap is integrally stamped and formed, the front skirt is a cylindrical structure, the front skirt is fitted on the outside of the front end cap and is circumferentially welded and fixed at the contact position.

[0007] Preferably, the rear end cap is integrally stamped, the rear skirt is a cylindrical structure, the rear skirt is fitted on the outside of the rear end cap and is circumferentially welded and fixed at the contact position.

[0008] Preferably, multiple cable supports are bonded and fixed to the outside of the composite material shell, and a support winding layer is formed by circumferentially winding a high-strength carbon fiber high-temperature resistant modified phenolic resin laminate on the outside of the composite material shell. The two ends of the support winding layer extend to the joint position of the front end cap and the front skirt and the joint position of the rear end cap and the rear skirt, respectively.

[0009] Another object of the present invention is to provide a method for molding a composite material shell for a solid rocket motor.

[0010] The technical solution adopted by this invention to solve the technical problems existing in the prior art is as follows: A method for forming a composite material shell for a solid rocket engine includes the following steps: S1, processing the parts separately to obtain a front end cap, a front skirt, a rear end cap, a rear skirt, and a straight section shell; S2, welding the front end cap and the front skirt to form a front shell, and welding the rear end cap and the rear skirt to form a rear shell; S3, welding the front shell to the straight section shell and the straight section shell to the rear shell to form a complete metal shell; S4, fabricating a high-strength carbon fiber high-temperature resistant modified phenolic resin laminate, wrapping the laminate circumferentially around the outside of the straight section shell, curing it to form a wound shell, and covering the shell welds between the front shell and the straight section shell and between the straight section shell and the rear shell at both ends of the wound shell, respectively. The wound shell and the metal shell together constitute a composite material shell.

[0011] Preferably, after forming the composite material shell, multiple cable supports are bonded and fixedly installed at predetermined positions on the shell, and a high-strength carbon fiber high-temperature resistant modified phenolic resin laminate is circumferentially wound on the outer surface of the composite material shell to form a support winding layer.

[0012] The advantages and positive effects of this invention are:

[0013] This invention provides a composite material shell for a solid rocket motor and its molding method. Compared with existing solid rocket motor shell structures and molding methods, the composite material shell of this invention adopts a scheme of a metal inner shell and a ring-wound carbon fiber outer shell, achieving equal strength design with the metal inner layer and the ring-wound composite material shell sharing the load. The composite material shell of this invention meets both the internal pressure bearing requirements of the engine and the thermal protection requirements at high temperatures, and the stiffness of the composite material shell meets the full payload requirements. The composite material shell of this invention effectively reduces the material cost, manufacturing and processing costs of the composite material shell. Due to its good heat resistance and strong thermal load resistance, the application of this composite material shell allows the solid rocket motor to eliminate the original external thermal protection structure, further reducing the construction cost of solid rockets. The composite material shell and its molding method of this invention can comprehensively improve the performance of solid rocket motors without significantly increasing production costs. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the main structure of the present invention;

[0015] Figure 2 This is a partial cross-sectional structural diagram of the forward section in this invention;

[0016] Figure 3 This is a partial cross-sectional structural diagram of the rear compartment in this invention;

[0017] Figure 4 This is a flowchart of the molding method in this invention.

[0018] In the picture:

[0019] 1. Front end cap; 2. Front skirt; 3. Straight cylindrical shell section; 4. Rear skirt; 5. Rear end cap; 6. Spiral wound shell; 7. Support spiral wound layer; 8. Cable support; 9. Shell weld. Detailed Implementation

[0020] To further understand the invention's content, features, and effects, the following embodiments are provided for detailed explanation.

[0021] Please see Figure 1 , Figure 2 and Figure 3 The composite material shell of the solid rocket motor of the present invention includes a front shell composed of a front end cap 1 and a front skirt 2 made of metal, and a rear shell composed of a rear end cap 5 and a rear skirt 4 made of metal. The front end cap 1 and the front skirt 2 are welded together, and the rear end cap 5 and the rear skirt 4 are welded together.

[0022] As shown in the figure, in this embodiment, the front end cap 1 is integrally stamped, the front skirt 2 is a cylindrical structure, the front skirt 2 is fitted onto the outside of the front end cap 1 and is circumferentially welded and fixed at the contact position. The rear end cap 5 is integrally stamped, the rear skirt 4 is a cylindrical structure, the rear skirt 4 is fitted onto the outside of the rear end cap 5 and is circumferentially welded and fixed at the contact position.

[0023] A straight cylindrical section of metal is provided between the front shell and the rear shell.

[0024] The front end of the straight cylindrical shell 3 is welded to the rear end of the front end cap 1, and the rear end of the straight cylindrical shell 3 is welded to the front end of the rear end cap 5. Figure 2 and Figure 3 As shown, a shell weld 9 is formed between the straight section shell 3 and the front end cap 1, and a shell weld 9 is formed between the straight section shell 3 and the rear end cap 5.

[0025] The front shell, the straight section shell 3, and the rear shell together constitute a complete metal shell, and the fuel of the solid rocket motor is added to the interior of the metal shell.

[0026] A carbon fiber wound shell 6 is provided on the outside of the straight cylindrical shell 3, and the two ends of the wound shell 6 cover the shell welds 9 between the front shell and the straight cylindrical shell 3, and between the straight cylindrical shell 3 and the rear shell, respectively. The wound shell 6 and the aforementioned metal shell together constitute a composite material shell.

[0027] The wound shell 6 is constructed as follows: a high-strength carbon fiber high-temperature modified phenolic resin laminate is made of carbon fiber material and high-temperature modified resin, and the aforementioned laminate is wound in a ring around the outside of the straight cylindrical shell 3 to form the wound shell 6.

[0028] The design principle of this invention for achieving lightweight rocket engine casing is as follows: Solid rocket engine casings are characterized by circumferential stress being twice the axial stress. This invention achieves equal strength in both the axial and circumferential directions by rationally designing the thickness of the metal casing and the composite casing, maximizing the effective strength of the materials and realizing a lightweight casing design. Specifically, the thickness of the straight section casing 3 in this invention is thinner than the thickness of the metal casings at both ends. A wound casing 6 is used to reinforce the outside of the straight section casing 3, improving the strength of the middle part of the composite material casing. Secondly, high-temperature resistant modified phenolic resin is used instead of ordinary epoxy resin, which improves the high-temperature resistance of the composite material casing and achieves an integrated thermal protection design.

[0029] Multiple cable supports 8 are bonded and fixed to the outside of the composite material shell. A support winding layer 7, formed by circumferentially winding a high-strength carbon fiber high-temperature modified phenolic resin laminate, is provided on the outer side of the composite material shell. The two ends of the support winding layer 7 extend to the joint positions of the front end cap 1 and the front skirt 2, and the rear end cap 5 and the rear skirt 4, respectively. The multiple cable supports 8 are used to securely connect the cables of the rocket engine.

[0030] The aforementioned method for molding the composite material shell of a solid rocket motor includes the following steps:

[0031] S1. The front end cap 1, front skirt 2, rear end cap 5, rear skirt 4 and straight section shell 3 are obtained by split processing. The front end cap 1 and rear end cap 5 are stamped and formed by themselves. The wall thickness of the front end cap 1 and the rear end cap 5 is equal. The wall thickness of the front end cap 1 and the rear end cap 5 is twice the wall thickness of the straight section shell 3.

[0032] S2. The front end cap 1 and the front skirt 2 are welded to form the front shell, and the rear end cap 5 and the rear skirt 4 are welded to form the rear shell. Specifically, the cylindrical front skirt 2 is fitted onto the outside of the front end cap 1 and the joint is continuously welded, and the cylindrical rear skirt 4 is fitted onto the outside of the rear end cap 5 and the joint is continuously welded.

[0033] S3. Weld the front shell to the straight section shell 3 and the straight section shell 3 to the rear shell to form a complete metal shell, and form a shell weld 9 between the front shell and the straight section shell 3 and between the straight section shell 3 and the rear shell.

[0034] As shown in the figure, the inner diameter of the front end cap 1 is equal to the inner diameter of the straight cylindrical shell 3, and the inner diameter of the rear end cap 5 is equal to the inner diameter of the straight cylindrical shell 3. After the three are welded together to form a metal shell, it can be seen that the middle part of the metal shell, that is, the outer side of the straight cylindrical shell 3, has a depression due to the different wall thicknesses of each section.

[0035] S4. A high-strength carbon fiber high-temperature resistant modified phenolic resin laminate is made. The laminate is wound circumferentially on the outside of the straight cylindrical shell 3 and cured to form a wound shell 6. The two ends of the wound shell 6 cover the shell welds 9 between the front shell and the straight cylindrical shell 3 and between the straight cylindrical shell 3 and the rear shell, respectively. The wound shell 6 and the metal shell together constitute a composite material shell.

[0036] As shown in the figure, the wound shell 6 is located in the aforementioned recess in the middle of the metal shell and completely fills the recess. From the outside of the resulting composite material shell, the wound shell 6 makes the outer surface of the composite material shell smooth.

[0037] In this embodiment, after the composite material shell is formed, multiple cable supports 8 are bonded and fixedly installed at preset positions on the shell. A high-strength carbon fiber high-temperature resistant modified phenolic resin laminate is circumferentially wound on the outer surface of the composite material shell to form a support winding layer 7. The cable supports 8 are set for arranging the cables of the solid rocket motor.

Claims

1. A composite material shell for a solid rocket motor, characterized in that: The front shell consists of a front end cap (1) and a front skirt (2) made of metal, and a rear shell consists of a rear end cap (5) and a rear skirt (4) made of metal. The front end cap (1) and the front skirt (2) are welded together, and the rear end cap (5) and the rear skirt (4) are welded together. A straight cylindrical shell (3) made of metal is provided between the front shell and the rear shell. The front end of the straight cylindrical shell (3) is welded to the rear end of the front end cap (1), and the rear end of the straight cylindrical shell (3) is welded to the front end of the rear end cap (5). A wound shell (6) made of high-strength carbon fiber high-temperature modified phenolic resin laminate is provided on the outside of the straight cylindrical shell (3). The two ends of the wound shell (6) cover the shell welds (9) between the front shell and the straight cylindrical shell (3) and between the straight cylindrical shell (3) and the rear shell, respectively.

2. The composite material casing of the solid rocket motor as described in claim 1, characterized in that: The front end cap (1) is integrally stamped and formed, and the front skirt (2) is a cylindrical structure. The front skirt (2) is fitted on the outside of the front end cap (1) and is circumferentially welded and fixed at the contact position.

3. The composite material casing of the solid rocket motor as described in claim 2, characterized in that: The rear end cap (5) is integrally stamped and formed, and the rear skirt (4) is a cylindrical structure. The rear skirt (4) is fitted on the outside of the rear end cap (5) and is circumferentially welded and fixed at the contact position.

4. The composite material casing of the solid rocket motor as described in claim 3, characterized in that: Multiple cable supports (8) are bonded and fixed to the outside of the composite material shell. A support winding layer (7) is formed by circumferentially winding a high-strength carbon fiber high-temperature resistant modified phenolic resin laminate on the outside of the composite material shell. The two ends of the support winding layer (7) extend to the joint position of the front end cap (1) and the front skirt (2) and the joint position of the rear end cap (5) and the rear skirt (4), respectively.

5. The method for molding the composite material shell of a solid rocket motor as described in any one of claims 1 to 4, characterized in that: Including the following step, S1. The front end cap (1), front skirt (2), rear end cap (5), rear skirt (4) and straight section shell (3) are obtained by split processing. S2. Weld the front end cap (1) and the front skirt (2) to form the front shell, and weld the rear end cap (5) and the rear skirt (4) to form the rear shell; S3. Weld the front shell to the straight section shell (3) and the straight section shell (3) to the rear shell to form a complete metal shell; S4. A high-strength carbon fiber high-temperature resistant modified phenolic resin laminate is made. The laminate is wound around the outside of the straight section shell (3) and cured to form a wound shell (6). The two ends of the wound shell (6) cover the shell welds (9) between the front shell and the straight section shell (3) and between the straight section shell (3) and the rear shell, respectively. The wound shell (6) and the metal shell together constitute a composite material shell.

6. The molding method for the composite material shell of a solid rocket motor as described in claim 5, characterized in that: After forming the composite material shell, multiple cable supports (8) are bonded and fixedly installed at preset positions on the shell, and a high-strength carbon fiber high-temperature resistant modified phenolic resin laminate is circumferentially wound on the outer surface of the composite material shell to form a support winding layer (7).

Images