Composite material transmitting tube with variable-thickness section structure and forming method

Abstract

The invention relates to a composite material transmitting tube with a variable-thickness section structure and a forming method, and the composite material transmitting tube comprises a front end frame (1), a rear end frame (2), and a composite tube body (3) used for connecting the front end frame (1) and the rear end frame (2); the composite tube body (3) comprises a front end frame connecting structure (31), a middle connecting structure (32) and a rear end frame connecting part structure (33) which are sequentially arranged in the longitudinal direction of the composite material transmitting tube. The middle connecting structure (32) is provided with a plurality of variable thickness parts (32A) which are sequentially connected in the circumferential direction; in the transverse direction of the composite material transmitting tube, the variable-thickness part (32A) is of a symmetrical structure, and the thickness of the variable-thickness part (32A) is gradually reduced in the direction from the middle to the edge. According to the scheme, the composite material launching tube which is excellent in strength and rigidity and light in weight is effectively provided, so that the composite material launching tube has a wider application range and potential.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of composite material launch tube forming, in particular to a composite material launch tube with variable-thickness cross-section structure and a forming method. BACKGROUND

[0002] As a key supporting equipment of modern special products (such as unmanned aerial vehicles, portable missiles, etc.), the launch tube integrates the functions of storage, transportation, detection and launching of the product, and its performance directly affects the corresponding technical indicators, service life and effectiveness of the product. Traditional launch tubes are mostly made of metal materials (such as high-strength steel, aluminum alloy, etc.). However, with the development of modern science and technology and the continuous improvement of performance requirements for special product equipment, the inherent technical bottlenecks of metal launch tubes are becoming increasingly prominent, mainly in the following aspects: excessive structural weight; poor environmental corrosion resistance; single function, low information integration; insufficient stealth and survivability, etc. Therefore, with the emergence of composite materials, many composite material launch tubes have appeared in the prior art, which basically use an approximate equal-wall-thickness replacement of metal launch tubes. However, due to the fundamental differences in material properties, key design objectives and failure mechanisms between composite materials and metals, such simple replacement is unreliable.

[0003] In addition, the core layer between the inner and outer skins of the existing composite material launch tube is usually made of low-density materials such as polyurethane foam, but such low-density materials have low strength and stiffness, which can seriously affect the overall rigidity and long-term dimensional stability of the launch tube. Moreover, the cross-sectional structure of the existing launch tube is an equal-thickness rectangular structure. This structure is prone to fiber arching when formed using the winding process. Such fiber arching is a serious structural defect that can directly lead to premature failure of the launch tube, making it unable to achieve the designed performance indicators, thereby causing safety hazards. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a composite material launch tube with a variable-thickness cross-section structure.

[0005] To achieve the above-mentioned application purposes, the present application provides a composite material launch tube with a variable-thickness cross-section structure, comprising: a front end frame, a rear end frame, and a composite tube body for connecting the front end frame and the rear end frame. The composite tube body comprises: a front end frame connecting structure, an intermediate connecting structure and a rear end frame connecting structure arranged in sequence along the longitudinal direction of the composite material launch tube. The intermediate connecting structure is provided with a plurality of variable-thickness portions (32A) connected in sequence along the circumferential direction. Along the transverse direction of the composite material launch tube, the variable-thickness portion is a symmetrical structure, and its thickness gradually decreases from the middle to the edge.

[0006] According to an aspect of the present application, the intermediate connecting structure comprises: an inner skin layer, an outer skin layer, and a plurality of core layers filled between the inner skin layer and the outer skin layer; The plurality of core layers are distributed along the circumference of the intermediate connecting structure, and along the thickness direction of the core layer, the opposite sides of the core layer are fixedly connected with the inner skin layer and the outer skin layer respectively to form the variable-thickness portion. The core layer is of a symmetrical structure, and its thickness gradually decreases from the middle to the edge.

[0007] According to an aspect of the present application, along the circumference of the intermediate connecting structure, the first longitudinal reinforcing structure is arranged between adjacent core layers.

[0008] According to an aspect of the present application, along the circumference of the intermediate connecting structure, the first longitudinal reinforcing structure is of a symmetrical structure, and its thickness gradually increases from the middle to the edge. Along the circumference of the intermediate connecting structure, the large-thickness end of the first longitudinal reinforcing structure is connected with the small-thickness end of the core layer, and the thickness at the abutting position is consistent.

[0009] According to an aspect of the present application, the core layer comprises: a second longitudinal reinforcing structure, and a balsa wood core symmetrically arranged on the opposite sides of the second longitudinal reinforcing structure. The second longitudinal reinforcing structure is fixedly connected with the balsa wood core.

[0010] According to an aspect of the present application, the first longitudinal reinforcing structure between adjacent core layers and the second longitudinal reinforcing structure in the core layer are both profiles prepared by a pultrusion process.

[0011] According to an aspect of the present application, the inner skin layer and the outer skin layer are both made of carbon fiber / medium-temperature epoxy material. The front-end frame connecting structure is an annular structure made of carbon fiber / medium-temperature epoxy material, and the front-end frame connecting structure is integrated with the outer skin layer. The rear-end frame connecting structure comprises: a first structure layer and a second structure layer. The first structure layer is fixedly sleeved on the outside of the second structure layer. The first structure layer and the second structure layer are both made of carbon fiber / medium-temperature epoxy material, the first structure layer is integrated with the outer skin layer, and the second structure layer is integrated with the inner skin layer.

[0012] According to an aspect of the present application, the front-end frame is a composite material end frame made of carbon fiber / medium-temperature epoxy material, and the ply design of the front-end frame is [90 / 45 / 0 / -45]s. The rear end frame is a metal material end frame, and an annular groove is arranged on one side of the rear end frame connected with the rear end frame connecting structure. The width of the annular groove is greater than the depth, and a chamfer is arranged on the edge of the opening side of the annular groove.

[0013] To achieve the above-mentioned purposes, the application provides a forming method of a composite material launch tube with variable thickness cross-section structure, comprising the following steps: S1. Design and prepare a corresponding mandrel mold based on the overall size of the composite material launch tube; S2. Fix the front end frame and the rear end frame on the mandrel mold, and install the combination on a winding machine; wherein, a release agent is applied on the surface of the mandrel mold; S3. Perform circumferential winding on the combination using a wet winding process, wherein, a second structural layer for the rear end frame connecting structure is formed on the rear end frame, and an inner skin layer for the intermediate connecting structure is formed on the surface of the mandrel mold; S4. Wind the second structural layer and the inner skin layer reaching the first thickness with OPP tape, and put the combination together into a curing oven for curing until the curing is completed; S5. Apply adhesive on the surface of the second structural layer and the inner skin layer after the curing is completed, and lay and glue the first longitudinal reinforcing structure and the core layer in turn and flat on the surface of the inner skin layer, and apply adhesive on the outer surface formed by the first longitudinal reinforcing structure and the core layer; S6. Install the combination on a winding machine and perform circumferential winding on the combination using a wet winding process; wherein, a front end frame connecting structure is formed on the front end frame, an outer skin layer is formed on the outer surface of the first longitudinal reinforcing structure and the core layer, and a first structural layer is formed on the outer side of the second structural layer; S7. Put the combination together into a curing oven for curing until the curing is completed, until the front end frame connecting structure, the outer skin layer and the first structural layer reach the second thickness preset thickness; After the curing is completed, the composite material launch tube is demolded, and the preparation is completed.

[0014] According to one aspect of the application, in step S3, in the step of performing circumferential winding on the combination using a wet winding process, carbon fiber / medium temperature epoxy material is used for circumferential winding to form a circumferential layer, and after each circumferential layer reaches the first preset number of layers, a longitudinal layer of 0° is laid in whole, until it stops when the first thickness is reached; In step S6, in the step of installing the combination on a winding machine and performing circumferential winding on the combination using a wet winding process, carbon fiber / medium temperature epoxy material is used for circumferential winding to form a circumferential layer, and after each circumferential layer reaches the second preset number of layers, a longitudinal layer of 0° is laid in whole, until it stops when the second thickness is reached; The second preset layer number is greater than the first preset layer number. The second thickness is greater than the first thickness, and the second thickness is 4mm-6mm.

[0015] According to one scheme of the present application, the scheme effectively provides a composite material launch tube with excellent strength, rigidity and light weight, so that the scheme has a wider application range and potential.

[0016] According to one scheme of the present application, the scheme effectively improves the overall structural rigidity, reduces the deformation of itself and external stress, and effectively improves the use reliability and stability of the scheme by designing a variable-thickness tube body and combining a longitudinal reinforcing structure.

[0017] According to one scheme of the present application, the scheme optimizes the connection mode of the rear end frame and the composite tube body, so that the rear end part can better adapt to the influence of extreme environment during launching products, and is combined with the composite material in the form of mechanical embedding, so as to fully ensure the key reinforcement of the rear end connection position, and based on the integrated forming, the scheme not only has better structural performance, but also has more excellent structural precision of the finished product.

[0018] According to one scheme of the present application, the scheme can effectively inhibit the structural deformation of a large-length-diameter-ratio launch tube under high internal pressure load, has good forming process and stable quality, is conducive to mass production, and is easier to be popularized and accepted.

[0019] According to one scheme of the present application, the scheme sets a variable-thickness part, so that the fiber tension can be more uniformly and stably applied to the film surface during preparation, the fiber buckling caused by unstable tension is reduced, the uniform and stable transmission of load is effectively ensured, and under the relatively uniform tension, the fibers are compacted and arranged closely, the internal porosity is low, the process control difficulty is reduced, and the structural stability is improved.

[0020] According to one scheme of the present application, the core layer adopts basswood as the main material, based on the high strength characteristics of the basswood, the stability of the overall structure in the scheme can be fully improved, the deformation amount is effectively reduced, and the shape of the scheme is processed into a symmetric transition structure with a thick middle and thin edges, which is used to support the special cross-section structure of the outer skin, so as to effectively improve the yield of finished products in the processing process.

[0021] According to one aspect of the present invention, by embedding a first longitudinal reinforcing structure and a second longitudinal reinforcing structure, the longitudinal strength and stiffness of the composite material launch tube can be greatly improved. This also effectively connects the internal and external structures, facilitating the transmission of internal pressure and improving the overall mechanical properties. Furthermore, the first and second longitudinal reinforcing structures can be pre-processed, which can improve the production efficiency of this solution to a certain extent during use.

[0022] According to one aspect of the present invention, this solution can be integrally formed through a winding process, which is simple, efficient, stable in quality, and produces high-strength products, effectively suppressing structural deformation of large aspect ratio transmitter tubes under high internal pressure loads.

[0023] According to one aspect of the present invention, the lightweighting of the composite material launch tube is further improved by using two low-density, high-strength materials: balsa wood and carbon fiber. Attached Figure Description

[0024] Figure 1 This is a structural diagram of a composite material launch tube according to one embodiment of the present invention; Figure 2 for Figure 1 A magnified view of position 'a' in the middle; Figure 3 for Figure 1 A magnified view of the area at position b in the middle; Figure 4 This is a cross-sectional view of the intermediate connection structure according to one embodiment of the present invention; Figure 5 for Figure 4 A magnified view of a portion of position B in the middle; Figure 6 for Figure 4 A magnified view of a portion of position A in the middle; Figure 7 This is a cross-sectional view of the connection between the rear end frame and the composite tube body according to one embodiment of the present invention. Detailed Implementation

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are merely some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0026] In the description of the embodiments of the present application, the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" express the orientation or positional relationship based on the orientation or positional relationship shown in the relevant drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore the above terms cannot be understood as a limitation of the present application.

[0027] The present application will be described in detail below in conjunction with the drawings and specific embodiments, which cannot be exhaustively described here, but the embodiments of the present application are not limited to the following embodiments.

[0028] In conjunction with Figure 1 , Figure 2 , Figure 3 and Figure 4 , according to an embodiment of the present application, a composite material launch tube of a variable thickness cross-section structure comprises: a front end frame 1, a rear end frame 2, and a composite tube body 3 for connecting the front end frame 1 and the rear end frame 2; in this embodiment, the front end frame 1 and the rear end frame 2 are both annular structural members for reinforcing the end portions of the composite material launch tube, so that the structure of this scheme is more firm and reliable. In this embodiment, the opposite ends of the composite tube body 3 are fixed with the front end frame 1 and the rear end frame 2 respectively, thereby ensuring the reliability and stability of the connection and effectively improving the service life of this scheme. Specifically, based on the particularity of the structure of the composite tube body 3, it can be directly formed on the front end frame 1 and the rear end frame 2 during the preparation of the composite tube body 3, realizing the simultaneous connection process and preparation process, effectively ensuring the molding efficiency of this scheme and the integrated implementation during the preparation process of the composite material launch tube, which is more conducive to maintaining the unity of the structural precision.

[0029] In this embodiment, the composite tube body 3 comprises: a front end frame connecting structure 31, an intermediate connecting structure 32, and a rear end frame connecting structure 33 arranged in sequence along the longitudinal direction of the composite material launch tube; wherein the intermediate connecting structure 32 is provided with a plurality of variable thickness portions 32A connected in sequence along the circumferential direction; along the transverse direction of the composite material launch tube, the variable thickness portions 32A are symmetrical structures, and their thickness gradually decreases from the middle to the edge.

[0030] In this embodiment, in order to ensure the reliable and stable support of the installed product inside the composite material launch tube, the inner wall surface sizes of the front end frame 1, the rear end frame 2, and the composite tube body 3 are set to be consistent and flush, thereby ensuring the consistency of the entire inner wall surface of the composite material launch tube and meeting the flatness requirement of the installed product, and under this design, the variable thickness portions 32A on the intermediate connecting structure 32 can present an internally flat and outwardly convex state.

[0031] Through the above setting, in the way of setting the variable thickness part 32A at the position of the intermediate connecting structure 32, on the one hand, the overall structural strength of the intermediate connecting structure 32 can be effectively improved, and the internal product installed can be effectively protected, on the other hand, through the variable thickness part 32A, the internal of the prepared intermediate connecting structure 32 can be more compact, which is more beneficial to improve the overall impact resistance of the composite material launch tube.

[0032] In combination with Figure 2 , Figure 3 and Figure 4 It is shown that according to an embodiment of the present application, the intermediate connecting structure 32 comprises: an inner skin layer 321, an outer skin layer 322, and a plurality of core layers 323 filled between the inner skin layer 321 and the outer skin layer 322; in the present embodiment, the plurality of core layers 323 are distributed along the circumference of the intermediate connecting structure 32, and along the thickness direction of the core layer 323, the opposite sides of the core layer 323 are respectively fixedly connected with the inner skin layer 321 and the outer skin layer 322 to form a variable thickness part 32A; in the present embodiment, the opposite sides of the core layer 323 can be fixedly connected with the inner skin layer 321 and the outer skin layer 322 by gluing, which can conveniently realize the contact and compactness of the connection position, and also effectively ensure that the overall structure has more reliable structural strength. Further, the core layer 323 is a symmetrical structure, and its thickness gradually decreases from the middle to the edge.

[0033] In the present embodiment, the side of the core layer 323 connected with the inner skin layer 321 is a plane, and the side connected with the outer skin layer 322 is an arc surface, so that the inner skin layer 321 presents a rectangular structure with four flat sides, and the outer skin layer 322 presents a rectangular structure with four arc sides.

[0034] Through the above setting, in the way of setting the variable thickness part 32A on the intermediate connecting structure 32, not only the overall structural strength is enhanced, but also it has the advantages of light weight and low cost, which can effectively promote its large-scale application. In addition, through the way of setting a plurality of variable thickness parts 32A, the symmetrical distribution of the plurality of variable thickness parts 32A around the intermediate connecting structure 32 can be conveniently realized, so that the overall light weight is realized while having better structural symmetry and balanced quality distribution.

[0035] Through the above arrangement, by means of arranging a plurality of variable-thickness portions 32A in the circumferential direction, effective protection of the internally mounted product can be achieved based on the convex structure of the variable-thickness portion 32A, the overall quality is sufficiently reduced, and at the same time, the pipe wall of the composite material launch tube is sufficiently thick, which provides sufficient buffer space for resisting external vibration and impact. Further, the structure of the core layer 323 can be more flexibly arranged to have a certain vibration absorption capacity while ensuring the reliability of the spacing structure, thereby making the present scheme have excellent anti-vibration protection performance while taking into account reliability.

[0036] In combination with Figure 4 and Figure 5 As shown in the drawings, according to an embodiment of the present application, a first longitudinal reinforcing structure 32a is arranged between adjacent core layers 323 along the circumferential direction of the intermediate connecting structure 32. In the present embodiment, the first longitudinal reinforcing structure 32a is a bent beam body as a whole, and the length direction thereof is consistent with the longitudinal direction of the composite material launch tube (i.e., the axial direction of the composite material launch tube), thereby further strengthening the corner position of the composite material launch tube through the arranged first longitudinal reinforcing structure 32a, which is more beneficial to improving the structural reliability of the present scheme. In the present embodiment, four variable-thickness portions 32A are arranged, and four first longitudinal reinforcing structures 32a are also arranged, thereby achieving all-around strengthening and protection in the circumferential direction and further improving the structural reliability of the present scheme. Of course, for other numbers of variable-thickness portions 32A, the targeted arrangement of the first longitudinal reinforcing structure 32a can also achieve flexible adjustment of the structural shape of the composite material launch tube. For example, when five variable-thickness portions 32A are arranged, five first longitudinal reinforcing structures 32a are also arranged, so that the overall composite material launch tube is deformed into a pentagonal structure, and the like, and only the bending angle of the first longitudinal reinforcing structure 32a needs to be controlled to be connected and mounted with the adjacent core layer 323, so as to ensure the connection of the positions in the circumferential direction.

[0037] In the present embodiment, in order to ensure the structural strength and reliability of the first longitudinal reinforcing structure 32a, the bending position thereof is achieved in a round-corner transition manner, which not only ensures the reliability and stability of the structure, but also sufficiently realizes the tight cementation with the inner skin layer 321 and the outer skin layer 322, which is more beneficial to further ensuring the strength of the positions of the structure.

[0038] In the present embodiment, the thickness of the first longitudinal reinforcing structure 32a is 1.5 to 4 mm, and the length is 4000 mm.

[0039] By setting the first longitudinal reinforcing structure 32a between adjacent core layers 323, the structural weaknesses between adjacent core layers 323 are effectively compensated, and the structural reliability and impact resistance of this solution are fully and effectively improved. In addition, by setting the first longitudinal reinforcing structure 32a, it is equivalent to adding a reinforcing beam structure at the connection position of adjacent variable thickness parts 32A, so that it has reliable support along the longitudinal direction, and provides a reliable guarantee for achieving the stable and reliable shape of the entire composite material launch tube.

[0040] By setting the first longitudinal reinforcing structure 32a as a bent structural member to fill between adjacent core layers 323, the internal space can be larger due to its thinner thickness while ensuring the structural strength between adjacent core layers 323, which is more effective in improving the capacity of this solution.

[0041] By setting the first longitudinal reinforcing structure 32a as a bent structural component, the material and molding process of the first longitudinal reinforcing structure 32a can be flexibly adjusted to make the first longitudinal reinforcing structure 32a have a certain elasticity at the corner position. Thus, when connected to the core layer 323, the elasticity generated at the corner position of the first longitudinal reinforcing structure 32a can provide a sufficient dissipation range for the vibration transmitted when the variable thickness part 32A is impacted. Therefore, it is more beneficial to improve the overall vibration resistance.

[0042] like Figure 5 As shown, according to one embodiment of the present invention, along the circumference of the intermediate connecting structure 32, the first longitudinal reinforcing structure 32a is a symmetrical structure, and its thickness gradually increases from the middle to the edge; wherein, along the circumference of the intermediate connecting structure 32, the thick end of the first longitudinal reinforcing structure 32a is connected to the thin end of the core layer 323, and the thickness at the connection position is consistent.

[0043] The above-mentioned design effectively ensures the continuity of the connection positions, resulting in a smoother shape for the intermediate connection structure 32. Furthermore, the consistent dimensions at the docking positions facilitate a more secure connection, which is beneficial for ensuring the overall structural strength and reliability. Moreover, by making the thickness of the first longitudinal reinforcing structure 32a variable, it is easier to achieve flexible settings at its corner positions, further enhancing the vibration resistance and damping effect of this design.

[0044] Combination Figure 4 and Figure 6As shown, according to an embodiment of the present application, the core layer 323 comprises: a second longitudinal reinforcing structure 323a, a balsa wood core 323b symmetrically arranged on both sides of the second longitudinal reinforcing structure 323a; in the embodiment, the second longitudinal reinforcing structure 323a is fixedly connected with the balsa wood core 323b; wherein the second longitudinal reinforcing structure 323a can be arranged in an I-beam structure, so that the installation and fixation of the second longitudinal reinforcing structure 323a and the balsa wood core 323b can be realized based on the mutual plug-in mode, and the contact area between them is also sufficiently increased, and the adhesive can be further arranged at the contact position to more effectively ensure the reliable and stable connection. Moreover, by arranging the second longitudinal reinforcing structure 323a in the I-beam structure, on the one hand, it itself has sufficient structural strength, and on the other hand, the performance of the structures of different materials can be combined and enhanced based on the nesting mode with the balsa wood core 323b, so that the characteristics of the second longitudinal reinforcing structure 323a and the balsa wood core 323b are considered at the connection position, and the structural stability of the core layer 323 as a whole is ensured.

[0045] In the embodiment, in order to ensure that the outer skin layer 322 has a smooth curve when connected with the core layer 323, the position where the second longitudinal reinforcing structure 323a is connected with the balsa wood core 323b is pre-processed into a shape matching the curve of the outer skin layer 322, so that the structural precision of the outer skin layer 322 in the processing process is ensured.

[0046] In the embodiment, the flange thickness and the web thickness of the second longitudinal reinforcing structure 323a are arranged in a ratio of 1:1.5, so that the middle position of the core layer 323 is strengthened by the thicker web, and the structure of the middle position of the core layer 323 is more reliable. In the embodiment, the intersection between the flange and the web is arranged as a round corner, so that the structure of the connection position is more reliable. Preferably, the flange thickness is 1 mm, and the web thickness is 1.5 mm. In addition, the length of the second longitudinal reinforcing structure 323a is 4000 mm.

[0047] In the embodiment, the side of the second longitudinal reinforcing structure 323a for winding the outer skin layer 322 is arranged to have an arc, so that when the second longitudinal reinforcing structure 323a is connected with the balsa wood core 323b, the surface arc of the second longitudinal reinforcing structure 323a matches the surface arc of the balsa wood core 323b, that is, the accurate butt joint of the connection position is realized, so that the shape of the outer skin layer 322 is smooth.

[0048] Through the above arrangement, the core layer 323 is arranged in the composite structure, which can effectively ensure the structural strength of the core layer 323 itself, and can effectively realize the close forming of the outer skin layer 322 based on the shape of the structure of the core layer 323 itself, so as to fully and effectively ensure the structural compactness of the intermediate connecting structure 32, and the constant tension winding is more easily realized during the preparation of the outer skin layer 322, and the compaction and close arrangement between structures are more effectively realized under uniform tension, the process control difficulty is reduced, the internal pores are eliminated, and the stability of the product is improved.

[0049] According to an embodiment of the present application, the inner side of the flange of the second longitudinal reinforcing structure 323a can be further provided with protrusions extending along the length direction of the second longitudinal reinforcing structure 323a, and the protrusions can be arranged at intervals in the width direction of the second longitudinal reinforcing structure 323a. Thus, the protrusions arranged can realize the matching and mounting of the balsa wood core 323b mounting position, so as to fully ensure the structural strength and stability of the connecting position. In the embodiment, the interval between the protrusions arranged on the inner side of the flange and the web is greater than the interval between the adjacent protrusions. In the embodiment, the cross-sectional shape of the protrusions can be rectangular, triangular, semicircular, trapezoidal, etc. Further, protrusions extending along the length direction of the second longitudinal reinforcing structure 323a can also be arranged on the side surface of the web, which can realize the mutual embedding connection of the end of the balsa wood core 323b, so as to realize reliable fixation of the connecting position, and on the other hand, the structure of the web can be enhanced. Especially, the protrusions arranged on the inner side of the flange and the side surface of the web can more fully fasten the balsa wood core 323b and the second longitudinal reinforcing structure 323a together, greatly inhibiting the possible slight sliding between them, which is more beneficial to the reliability of the structure. In the embodiment, the cross-sectional shape of the protrusions arranged on the side surface of the web can be rectangular or trapezoidal, wherein if the trapezoidal shape is arranged, the narrow end of the trapezoidal shape is fixedly connected with the web, so that the protrusion cooperates more closely and reliably with the end of the balsa wood core 323b.

[0050] According to an embodiment of the present application, the first longitudinal reinforcing structure 32a between the adjacent core layers 323 and / or the second longitudinal reinforcing structure 323a in the core layer 323 are profiles prepared by a pultrusion process; specifically, the first longitudinal reinforcing structure 32a and / or the second longitudinal reinforcing structure 323a are molded by a pultrusion process using a carbon fiber / epoxy material system. Of course, the first longitudinal reinforcing structure 32a and the second longitudinal reinforcing structure 323a are not limited to the above molding method, for example, mechanical processing, stamping, etc. can be used for molding, which will not be described here.

[0051] Through the above setting, the lightweight of the first longitudinal reinforcing structure 32a and the second longitudinal reinforcing structure 323a can be more easily realized in the case of effectively ensuring the structural strength of the first longitudinal reinforcing structure 32a and the second longitudinal reinforcing structure 323a, and the structural reliability of the present scheme is reliably ensured.

[0052] According to an embodiment of the present application, the inner skin layer 321 and the outer skin layer 322 are both made of carbon fiber / medium-temperature epoxy material; specifically, T700-grade carbon fiber / medium-temperature epoxy system material can be used to fully ensure the structural strength of the inner skin layer 321 and the outer skin layer 322.

[0053] In the present embodiment, the thickness of the inner skin layer 321 is 2 mm. Through the above setting, the structural strength and reliability of the inner skin layer 321 are effectively ensured, and the compactness of the structural size is also effectively realized, which is more beneficial to the miniaturization and overall lightweight of the present scheme. Matching therewith, the thickness of the outer skin layer 322 can be set to 4 mm to 6 mm, which is more beneficial to ensuring the reliable stability of the appearance structure of the present scheme based on the thicker outer skin layer 322.

[0054] In the present embodiment, the front end frame connecting structure 31 is an annular structure made of carbon fiber / medium-temperature epoxy material, and the front end frame connecting structure 31 is integrated with the outer skin layer 322; specifically, T700-grade carbon fiber / medium-temperature epoxy system material can be used to fully ensure the structural strength of the front end frame connecting structure 31.

[0055] In combination with FIGS. 1 to 3, Figure 3 and Figure 7 As shown in FIGS. 1 to 3, according to an embodiment of the present application, the rear end frame connecting structure 33 includes a first structure layer 331 and a second structure layer 332; the first structure layer 331 is fixedly sleeved outside the second structure layer 332; the first structure layer 331 and the second structure layer 332 are both made of carbon fiber / medium-temperature epoxy material, and the first structure layer 331 is integrated with the outer skin layer 322, and the second structure layer 332 is integrated with the inner skin layer 321; specifically, T700-grade carbon fiber / medium-temperature epoxy system material can be used to fully ensure the structural strength of the first structure layer 331 and the second structure layer 332.

[0056] As shown in FIGS. 1 to 3, Figure 2As shown, according to an embodiment of the present application, the front end frame 1 is a composite material end frame made of carbon fiber / medium temperature epoxy material, and the ply design of the front end frame 1 is [90 / 45 / 0 / -45]s; specifically, the front end frame 1 is made of T700 grade carbon fiber / medium temperature epoxy system material, thereby effectively ensuring the structural strength while making it lighter in mass and lower in cost. Moreover, by being made of the same material as the inner skin layer 321 and the outer skin layer 322, it is more conducive to ensuring the consistency of the overall physical properties after connection. In the present embodiment, the front end frame 1 includes a ring-shaped front end frame body and a first ring-shaped reinforcing protrusion arranged at the front end of the ring-shaped front end frame body; wherein the intermediate connection structure 32 can be fixedly connected to each other by being connected to the ring-shaped front end frame body. In the present embodiment, the ring-shaped front end frame body has a certain longitudinal length (i.e. axial length), thereby effectively increasing the connection area with the intermediate connection structure 32, and further more effectively improving the reliability and stability of the connection.

[0057] In combination Figure 3 and Figure 7 As shown, according to an embodiment of the present application, the rear end frame 2 is a metal material end frame, and an annular groove 21a is arranged on the side of the rear end frame 2 connected to the rear end frame connection structure 33. In the present embodiment, the rear end frame 2 includes a ring-shaped rear end frame body and a second ring-shaped reinforcing protrusion arranged at the rear end of the ring-shaped rear end frame body; wherein the annular groove 21a is arranged on the outer side surface of the ring-shaped rear end frame body. In the present embodiment, the annular groove 21a can be arranged in multiple, thereby more effectively enhancing the connection strength with the intermediate connection structure 32. In the present embodiment, the width of the annular groove 21a is greater than the depth, and a chamfer is arranged on the edge of the opening side of the annular groove 21a. Specifically, the width of the annular groove 21a can be set to 2mm, the depth is set to 1mm, and the chamfer arranged on the edge of the opening side is 7.5°, thereby forming a sawtooth shape on the ring-shaped rear end frame body by arranging multiple annular grooves 21a, which can more easily form a structure matching the sawtooth at the connection position during the processing of the inner skin layer 321 and the rear end frame connection structure 33, and more effectively improves the reliability of the connection position.

[0058] In the embodiment, the chamfer surface of the edge of the annular groove 21a opening side can be further provided with a rough structure, wherein the rough structure can be discrete protrusions and / or recesses, or can be provided as an annular groove or annular protrusion coaxially distributed along the chamfer surface (wherein the depth of the annular groove or the height of the annular protrusion can be set to 0.5 to 1 times the diameter of the wound fiber), or can be provided as a spiral groove or spiral protrusion extending helically along the chamfer surface (wherein the depth of the spiral groove or the height of the spiral protrusion can be set to 0.5 to 1 times the diameter of the wound fiber); thus, the chamfer surface provided can effectively avoid the occurrence of faults during winding, so that the surface at the formed sawtooth position can still stably adhere to the corresponding fiber tows, thereby being more advantageous for improving the stability and reliability of the connection between the structures.

[0059] In the embodiment, the rear end frame 2 as a whole can be made of one of Q235 steel, 40Cr alloy steel, aluminum alloy, and titanium alloy, so that the rear end frame 2 can more effectively adapt to the high-temperature combustion gas generated by the installed product, and can also withstand greater internal pressure, reduce corresponding deformation, and improve the structural reliability of the rear end position. Of course, under the condition of meeting the extreme environment adaptation requirement during product launching, the rear end frame 2 can also be provided as a composite material structure, so that the material selection is more extensive and flexible.

[0060] Through the above setting, the present scheme realizes the adaptability optimization of the overall structure of the composite material launching tube by setting the front end frame 1 and the rear end frame 2 to be different materials, wherein the front end frame 1 made of carbon fiber / medium-temperature epoxy material can effectively ensure the structural strength and low deformation requirement, and can also eliminate the anti-corrosion treatment requirement and the process complexity of the traditional metal parts. By using the metal material of the rear end frame 2, the present scheme has more reliable adaptability to the extreme environment generated during the product launching process at the rear end position, thereby improving the use safety of the present scheme.

[0061] According to an embodiment of the present application, along the longitudinal direction of the composite material launching tube, the thickness of the tube wall of the composite material launching tube can be consistent from front to back, or can be set to be inconsistent from front to back, so that the area with greater pressure can be locally thickened to reduce local deformation and improve strength. For example, the thickness of the tube wall of the composite material launching tube can gradually increase along the direction from the front end frame 1 to the rear end frame 2, so that the rear end position of the composite material launching tube has a tube wall that is further back to sufficiently increase the structural strength of the rear end position. Of course, the structural strength of the rear end position can also be increased by directly using a stepped thickening manner at a certain distance from the rear end, and this stepped thickening manner can be more flexible for setting the corresponding position.

[0062] According to an embodiment of the present application, a forming method of a composite material launch tube with a variable-thickness cross-section structure comprises the following steps: S1. Design and prepare a corresponding mandrel mold based on the overall size of the composite material launch tube; S2. Fix the front end frame 1 and the rear end frame 2 on the mandrel mold, and install the combination on a winding machine; wherein, a release agent is applied on the surface of the mandrel mold; S3. Perform circumferential winding on the combination using a wet winding process, wherein, a second structural layer 332 for the rear end frame connecting structure 33 is formed on the rear end frame 2, and an inner skin layer 321 for the intermediate connecting structure 32 is formed on the surface of the mandrel mold; S4. Wind the second structural layer 332 and the inner skin layer 321 reaching a first thickness with an OPP tape, and place the combination together in a curing oven for curing until completion; S5. Apply adhesive on the surface of the second structural layer 332 and the inner skin layer 321 after curing, and sequentially and evenly lay and glue the first longitudinal reinforcing structure 32a and the core layer 323 on the surface of the inner skin layer 321, and apply adhesive on the outer surface formed by the first longitudinal reinforcing structure 32a and the core layer 323; S6. Install the combination on a winding machine and perform circumferential winding on the combination using a wet winding process; wherein, a front end frame connecting structure 31 is formed on the front end frame 1, an outer skin layer 322 is formed on the outer surface of the first longitudinal reinforcing structure 32a and the core layer 323, and a first structural layer 331 is formed on the outer side of the second structural layer 332; S7. Place the combination together in a curing oven for curing until completion until the front end frame connecting structure 31, the outer skin layer 322, and the first structural layer 331 reach a second thickness preset thickness; After curing, the composite material launch tube is demolded, and the preparation is completed.

[0063] According to an embodiment of the present application, in step S1, the step of designing and preparing a corresponding mandrel mold based on the overall size of the composite material launch tube, the mandrel mold can be made of metal materials such as steel and aluminum, or can be made of resin-based composite materials (such as common glass steel mold, carbon fiber mold, etc.); wherein, the specific shape and size of the mandrel mold are determined based on the overall shape and size of the composite material launch tube prepared thereby, which will not be described here.

[0064] According to an embodiment of the present application, in step S2, the front end frame 1 and the rear end frame 2 are fixed on the mandrel mold, and the assembly is installed on the winding machine. During the preparation of the mandrel mold, the positioning and clamping structure of the mandrel mold can be set based on the installation of the front end frame 1 and the rear end frame 2 to achieve fixed installation. In order to ensure the smooth demolding of the finished product, a release agent can be applied to the surface of the mandrel mold between the front end frame 1 and the rear end frame 2. The release agent used is a liquid release agent that allows the finished product to be separated from the mold after curing without damaging the product, thereby fully ensuring the surface quality of the product.

[0065] According to an embodiment of the present application, in step S3, the assembly is circumferentially wound using a wet winding process. Carbon fiber / medium temperature epoxy material is used for circumferential winding to form a circumferential layer. When the circumferential layer reaches a first predetermined number of layers, a 0° longitudinal layer is laid on the circumferential whole, and the process stops when the first thickness is reached. Both the circumferential layer and the longitudinal layer are T700 grade carbon fiber / medium temperature epoxy material layers. In an embodiment, the first thickness can be set to 2mm.

[0066] According to an embodiment of the present application, in step S4, the assembly is placed together in a curing oven for curing until the curing is completed. The curing time and temperature are determined based on the required performance of the second structural layer 332 and the inner skin layer 321, which will not be described here. In this embodiment, the resin material in the carbon fiber / medium temperature epoxy material has a certain viscosity during the winding process, so after curing, the front end frame 1 and the inner skin 321 can be stably connected.

[0067] According to an embodiment of the present application, in step S5, an adhesive is applied to the surface of the cured second structural layer 332 and the inner skin layer 321, and the first longitudinal reinforcing structure 32a and the core layer 323 are sequentially and evenly laid and glued to the surface of the inner skin layer 321. The adhesive used is one or more of epoxy resin, polyurethane, acrylate, and phenolic resin. The choice of adhesive depends on the material being bonded, the use environment, the mechanical properties required, the process requirements, the cost, and other factors, which will not be described here. In this embodiment, during the process of sequentially and evenly laying and gluing the first longitudinal reinforcing structure 32a and the core layer 323 to the surface of the inner skin layer 321, the surface of the first longitudinal reinforcing structure 32a, the surface of the second longitudinal reinforcing structure 323a, and the surface of the basswood core 323b need to be in full contact with the adhesive to ensure stable and reliable fixation at each position.

[0068] In the embodiment, in the step S5, the step of applying adhesive to the outer surface of the first longitudinal reinforcing structure 32a and the core layer 323, the adhesive can be one or more of epoxy resin, polyurethane, acrylate, phenolic resin, which can be selected according to the bonding material, the use environment, the mechanical property requirement, the process requirement, the cost and other factors, which will not be described here.

[0069] According to an embodiment of the present application, in the step S6, the step of installing the combination on the winding machine and using the wet winding process to perform the hoop winding of the combination, the hoop winding is performed by using carbon fiber / medium-temperature epoxy material to form the hoop layer, and a longitudinal layer of 0° is laid on the whole hoop body every time the second preset layer number (of course, the preset single layer thickness can also be used) is reached, until the second thickness is reached; wherein the second preset layer number is greater than the first preset layer number; for example, the second preset layer number is set to 4 layers, and the first preset layer number is set to 3 layers. In addition, in the winding process, the way of selectively adding part of the hoop layer and / or the longitudinal layer to increase the size of part of the position can be set, and the winding process is consistent with the principle of the foregoing winding process, which will not be described here.

[0070] According to an embodiment of the present application, in the step S7, the step of until the front end frame connecting structure 31, the outer skin layer 322 and the first structure layer 331 reach the second thickness preset thickness, the second thickness is greater than the first thickness, and the second thickness is 4mm-6mm.

[0071] In the embodiment, in the step S7, the step of placing the combination together into the curing oven for curing until the curing is completed, the curing time and the curing temperature are determined according to the required performance of the second structure layer 332 and the inner skin layer 321, which will not be described here.

[0072] Through the above setting, the present scheme can prepare a large-size composite material launch tube with a length of 4.3m and a length-diameter ratio of about 16.7, and can ensure the stiffness of the large-length-diameter-ratio launch tube under high internal pressure load.

[0073] In the embodiment, the first structure layer 331, the second structure layer 332 and the rear end frame 2 can be further fixed by rivets to more effectively ensure the reliable stability of the connection position.

[0074] In this embodiment, the first structural layer 331 is integral with the outer skin layer 322, and the second structural layer 332 is integral with the inner skin layer 321. Thus, the first structural layer 331, the second structural layer 332, and the rear frame 2 can be connected. At this time, the first longitudinal reinforcing structure 32a and the second longitudinal reinforcing structure 323a are completely surrounded between the outer skin layer 322 and the inner skin layer 321. Furthermore, the front end of the core layer 323 can be chamfered, which facilitates a smooth transition between the outer skin layer 322 and the front frame connection structure 31, ensuring a seamless and continuous connection.

[0075] The above description is merely an example of a specific solution of the present invention. For any devices and structures not described in detail herein, it should be understood that they are implemented using common devices and methods already available in the art.

[0076] The above description is merely one embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the invention by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A composite material launch tube with a variable thickness cross-section, characterized in that, include: Front frame (1), rear frame (2), composite tube (3) for connecting the front frame (1) and the rear frame (2). The composite tube body (3) includes: a front end frame connection structure (31), an intermediate connection structure (32) and a rear end frame connection structure (33) arranged sequentially along the longitudinal direction of the composite material tube. The intermediate connecting structure (32) is provided with multiple variable thickness portions (32A) connected sequentially along the circumferential direction. Along the transverse direction of the composite material emitter tube, the variable thickness portion (32A) has a symmetrical structure, and its thickness gradually decreases from the middle to the edge.

2. The composite material launch tube with a variable thickness cross-section structure according to claim 1, characterized in that, The intermediate connection structure (32) includes: an inner skin layer (321), an outer skin layer (322), and a plurality of core layers (323) filled between the inner skin layer (321) and the outer skin layer (322). Multiple core layers (323) are distributed circumferentially along the intermediate connecting structure (32), and along the thickness direction of the core layer (323), the opposite sides of the core layer (323) are fixedly connected to the inner skin layer (321) and the outer skin layer (322) respectively to form the variable thickness portion (32A). The core layer (323) has a symmetrical structure and its thickness gradually decreases from the middle to the edge.

3. The composite material launch tube with a variable thickness cross-section structure according to claim 2, characterized in that, Along the circumferential direction of the intermediate connecting structure (32), a first longitudinal reinforcing structure (32a) is provided between adjacent core layers (323).

4. The composite material launch tube with a variable thickness cross-section structure according to claim 3, characterized in that, Along the circumference of the intermediate connecting structure (32), the first longitudinal reinforcing structure (32a) is a symmetrical structure, and its thickness gradually increases from the middle to the edge. Along the circumference of the intermediate connecting structure (32), the thick end of the first longitudinal reinforcing structure (32a) is connected to the thin end of the core layer (323), and the thickness at the connection position is consistent.

5. The composite material launching tube with a variable thickness cross-section structure according to any one of claims 2 to 4, characterized in that, The core layer (323) includes: a second longitudinal reinforcing structure (323a), and balsa wood cores (323b) symmetrically arranged on both sides of the second longitudinal reinforcing structure (323a); The second longitudinal reinforcing structure (323a) is fixedly connected to the balsa wood core (323b).

6. The composite material launch tube with a variable thickness cross-section structure according to claim 5, characterized in that, The first longitudinal reinforcing structure (32a) between adjacent core layers (323) and / or the second longitudinal reinforcing structure (323a) in the core layer (323) are both profiles prepared by pultrusion molding process.

7. The composite material launching tube with a variable thickness cross-section structure according to any one of claims 2 to 4, characterized in that, Both the inner skin layer (321) and the outer skin layer (322) are made of carbon fiber / medium-temperature epoxy material; The front frame connection structure (31) is a ring structure made of carbon fiber / medium temperature epoxy material, and the front frame connection structure (31) and the outer skin layer (322) are integrated. The rear frame connection structure (33) includes: a first structural layer (331) and a second structural layer (332); The first structural layer (331) is fixedly sleeved on the outside of the second structural layer (332); The first structural layer (331) and the second structural layer (332) are both made of carbon fiber / medium-temperature epoxy material, and the first structural layer (331) is integrated with the outer skin layer (322), and the second structural layer (332) is integrated with the inner skin layer (321).

8. The composite material launching tube with a variable thickness cross-section structure according to any one of claims 1 to 4, characterized in that, The front end frame (1) is a composite material end frame made of carbon fiber / medium temperature epoxy material, and the layup design of the front end frame (1) is [90 / 45 / 0 / -45]s; The rear end frame (2) is a metal end frame, and an annular groove (21a) is provided on the side where the rear end frame (2) is connected to the rear end frame connection structure (33). The width of the annular groove (21a) is greater than its depth, and a chamfer is provided on the edge of the opening side of the annular groove (21a).

9. A method for molding a composite material transmitter tube with a variable thickness cross-section, characterized in that, Includes the following steps: S1. Based on the overall external dimensions of the composite material launch tube, the corresponding mandrel mold was designed and prepared; S2. Fix the front end frame (1) and the rear end frame (2) on the mandrel mold, and install the assembly on the winding machine; wherein, apply a release agent to the surface of the mandrel mold; S3. The assembly is wound circumferentially using a wet winding process, wherein a second structural layer (332) for the rear end frame connection structure (33) is formed on the rear end frame (2), and an inner skin layer (321) for the intermediate connection structure (32) is formed on the surface of the mandrel mold. S4. Wrap the second structural layer (332) and the inner skin layer (321) to the first thickness with OPP tape, and put the assembly into the curing oven for curing until curing is complete; S5. Apply adhesive to the surface of the cured second structural layer (332) and inner skin layer (321), lay the first longitudinal reinforcing structure (32a) and core layer (323) flat and bond them to the surface of the inner skin layer (321), and apply adhesive to the outer surface formed by the first longitudinal reinforcing structure (32a) and core layer (323); S6. The assembly is mounted on a winding machine and the assembly is wound circumferentially using a wet winding process; wherein, a front-end frame connecting structure (31) is formed on the front-end frame (1), an outer skin layer (322) is formed on the outer surface of the first longitudinal reinforcing structure (32a) and the core layer (323), and a first structural layer (331) is formed on the outer side of the second structural layer (332). S7. Until the front frame connecting structure (31), outer skin layer (322) and first structural layer (331) reach the second preset thickness, put the assembly into the curing oven for curing until curing is complete; After the composite material emitter tube has cured, it is demolded to complete the preparation.

10. The molding method of the composite material transmitter tube with variable thickness cross-section structure according to claim 9, characterized in that, In step S3, the step of circumferentially winding the assembly using wet winding process involves using carbon fiber / medium-temperature epoxy material for circumferential winding to form a circumferential layer. After each circumferential layer reaches the first preset number of layers, a 0° longitudinal layer is then laid out as a whole until the first thickness is reached. In step S6, when the assembly is installed on the winding machine and the assembly is wound circumferentially using a wet winding process, carbon fiber / medium-temperature epoxy material is used for circumferential winding to form a circumferential layer. After the circumferential layer reaches the second preset number of layers, a 0° longitudinal layer is laid as a whole until the second thickness is reached. The second preset number of layers is greater than the first preset number of layers; The second thickness is greater than the first thickness, and the second thickness is 4mm-6mm.

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