Hemispherical metal end socket-composite material cylinder heterogeneous connection underwater pressure-resistant shell

Abstract

The invention discloses an underwater pressure-resistant shell with heterogeneous connection of a hemispherical metal end socket and a composite barrel. The underwater pressure-resistant shell comprises a metal end socket, a connecting structure and a composite material barrel, the metal end socket and the connecting structure are integrally formed and manufactured, the connecting structure is provided with an annular flange, and a plurality of bosses are arranged in the circumferential direction of the annular flange at equal intervals; the composite material barrel comprises a grid rib inner layer and an annular winding layer, the grid rib inner layer is connected with the metal end socket through a connecting structure, and the annular winding layer is arranged on the outer side of the grid rib inner layer. According to the underwater pressure-resistant shell, the thought of'division and treatment 'is adopted, the metal end socket, the grid rib inner layer and the annular winding layer bear bending, axial pressure and annular pressure respectively, and a continuous fiber winding connection method is adopted, so that stress is more uniformly distributed in fibers; and in addition, a connection mode of combining macroscopic mechanical interlocking and microcosmic interface interlocking is adopted, the overall strength and rigidity of the structure and the reliability and sealing performance of connection are improved, and meanwhile the lightweight level of the overall structure is guaranteed.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of underwater pressure hulls, and particularly relates to a semi-spherical metal head-heterogeneous connection composite cylinder underwater pressure hull. BACKGROUND

[0002] Deep-sea submersibles are ocean equipment facing the national major strategic needs, and gradually develop towards large depth, large size and light weight. The pressure hull structure (outer shell) is not only a key component for protecting the safe operation of internal personnel, equipment and the like, but also significantly reflects the light weight level of the submersible. Composite materials have the advantages of small density, high specific strength and high specific modulus, and the pressure hull made of carbon fiber composite material shows great application potential. Compared with metal pressure hulls, composite material pressure hulls have greater working depth under a given buoyancy coefficient. The shape of the composite material pressure hull is usually cylindrical to improve the space utilization rate, reduce the motion resistance, be easy to process and manufacture, and bear external hydrostatic pressure by reducing the bending moment. The shell body is usually provided with a semi-spherical head at both ends to form a "capsule type" pressure hull body. However, due to the limitation of manufacturing process, composite materials are difficult to be used to prepare structures with high curvature, and the spherical head bears high bending load, and the bending load bearing capacity of the composite material is far less than the tensile and compressive bearing capacity. Therefore, the application provides a semi-spherical metal head-composite cylinder heterogeneous connection underwater pressure hull, which designs a connection form combining macroscopic mechanical interlocking and microscopic interface interlocking, solves the problems of low reliability (such as glue joint, welding, etc.), large destruction (such as bolt connection, riveting, etc.), and uneven stress distribution caused by discontinuous fibers of the connection structure in the prior art, and simultaneously realizes further weight reduction of the pressure hull. SUMMARY

[0003] In view of the heterogeneous connection of the metal head and the composite cylinder in the underwater pressure hull, the application provides a semi-spherical metal head-composite cylinder heterogeneous connection underwater pressure hull, which designs a metal head winding flange and a boss transition structure, connects the metal head and the composite grid reinforced structure through winding construction, and forms a mechanical interlocking structure. The grid reinforced structure is uniformly and annularly wound on the outside to form a complete pressure hull structure. The connection structure improves the connection strength on the basis of not damaging the fiber continuity, thereby improving the bearing performance of the connection structure and further improving the light weight of the overall structure. In addition, the connection structure provided by the application is simple in process implementation and strong in designability.

[0004] To solve the above problems, the application provides a hemispherical metal head-composite cylinder heterogeneous connection underwater pressure-resistant shell, which comprises two hemispherical metal heads, a connecting structure and a composite cylinder, the metal head and the connecting structure are integrally formed, the connecting structure is provided with an annular flange, and a plurality of bosses are arranged at equal intervals in the circumferential direction of the annular flange; the composite cylinder comprises a grid rib inner layer and a hoop winding layer, the grid rib inner layer is connected with the metal head through the connecting structure, and the outer side of the grid rib inner layer is the hoop winding layer; the grid rib inner layer and the hoop winding layer are both made of continuous fibers; in the winding process, the bosses are embedded in the grid rib inner layer through the hanging yarn, so that the mechanical interlocking of the metal head and the composite cylinder is realized.

[0005] Further, the grid rib inner layer adopts a diamond configuration or a rectangular configuration, and the rib angle and the spacing are calculated by geometric relationship:

[0006]

[0007] w=scosθ

[0008] In the formula, s is the circumferential spacing of the boss, θ is the rib angle, n is the number of circumferential arrangement of the boss, L is the length of the composite shell, D is the inner diameter of the shell, w is the rib spacing, i is the number of boss intervals between the upper and lower heads, i is 0 to ∞, i=0, θ=0°, that is, rectangular configuration; when i is larger, θ is larger, that is, diamond configuration.

[0009] Further, the thickness t1 of the grid rib inner layer and the thickness t2 of the hoop winding layer are calculated according to the following axial buckling and external pressure buckling formula to bear the axial and hoop forces of the external pressure load p respectively;

[0010]

[0011] In the formula, R is the inner radius of the shell, b is the rib width, μ1 and μ2 are the Poisson's ratios in the fiber direction and the fiber vertical direction respectively, and E1 and E2 are the elastic moduli in the fiber direction and the fiber vertical direction respectively.

[0012] Further, the thickness h and the length Rl of the annular flange are determined according to the formula derived by force analysis;

[0013]

[0014] Rl=2t1.

[0015] Further, the shape of the boss is a square column, a circular column, a square cone or a pyramid, and the height, axial length and hoop width of the boss need to be less than or equal to the thickness of the annular flange.

[0016] Further, the edge of the boss is provided with a round arc chamfer by sandpaper polishing to weaken the stress concentration degree, and the chamfer radius is 1-3 mm.

[0017] Further, the inner layer of the grid rib is provided with a continuous fiber wet winding process, during the winding process, the yarn is wound around the boss in the form of a hanging yarn, and the winding sequence is according to the 'Z' type winding, so that the metal end cover is inserted into the end of the inner layer of the grid rib to realize the connection between the metal end cover and the composite cylinder.

[0018] Further, the inner layer of the grid rib is provided with a continuous fiber wet winding process, during the winding process, the yarn is wound around the boss in the form of a hanging yarn, and the winding sequence is according to the 'Z' type winding, so that the metal end cover is inserted into the end of the inner layer of the grid rib to realize the connection between the metal end cover and the composite cylinder.

[0019] Further, the connection structure and the connection area of the composite cylinder are designed to enhance the structural characteristics of the connection, including sandpaper polishing, sand blasting, laser etching, and electrochemical corrosion, and the connection interface roughness needs to be greater than 1.5, and the connection interface is coated with an epoxy resin adhesive to improve the interface bonding strength and sealing performance.

[0020] Compared with the prior art, the present application has the following beneficial effects:

[0021] 1. The metal end cover and the composite material connection pressure shell of the present application can greatly reduce the weight of the pure metal pressure shell;

[0022] 2. The composite cylinder of the present application comprises an inner layer of grid rib and a hoop winding layer, which can more reasonably share the axial component and the hoop component under external pressure, and can further reduce the weight of the composite cylinder without grid rib;

[0023] 3. The metal end cover and the composite material pressure shell connection structure of the present application combines the characteristics of macroscopic mechanical interlocking high bearing capacity and microscopic interface adhesive high sealing performance, reduces the interruption of fibers, makes the stress distribution more uniform, and has stronger structure destruction resistance. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0025] Figure 1This is a schematic structural diagram of an underwater pressure hull with a hemispherical metal head and a composite material cylinder heterogeneously connected, provided by an embodiment of the present invention;

[0026] Figure 2 This is a partial enlarged view of the connection structure between the metal head and the composite material cylinder provided by an embodiment of the present invention;

[0027] Figure 3 This is a schematic structural diagram of a metal head provided by an embodiment of the present invention;

[0028] Figure 4 This is a schematic structural diagram of the inner layer of the mesh ribs provided by an embodiment of the present invention;

[0029] Figure 5 Schematic diagram of the winding process of the inner layer of the mesh reinforcement provided by an embodiment of the present invention;

[0030] Figure 6 is a three-dimensional schematic diagram of an underwater pressure hull structure provided by an embodiment of the present invention;

[0031] In the figure: 1-metal head; 2-circumferential winding layer; 3-mesh rib inner layer; 4-annular flange; 5-boss; 6-wire slot. DETAILED DESCRIPTION

[0032] In order to better understand the technical solution of the present application, the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0033] It should be clear that the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0034] The terms used in the embodiments of the present application are for the purpose of describing specific embodiments only and are not intended to limit the present application. The singular forms "a", "an", "the" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise.

[0035] like Figures 1-3As shown, the present application provides a kind of hemispherical metal head-composite cylinder heterogeneous connection underwater pressure shell, including two hemispherical metal head 1, connecting structure and composite cylinder, wherein, the metal head 1 with the connecting structure is made by integral forming, the connecting structure is equipped with annular flange 4, and several bosses 5 are arranged equidistantly in the circumferential direction of annular flange 4;The composite cylinder includes grid rib inner layer 3 and hoop winding layer 2, the grid rib inner layer 3 is connected with the metal head 1 by the connecting structure, and the outer side of the grid rib inner layer 3 is hoop winding layer 2;The grid rib inner layer 3 and hoop winding layer 2 are both made by continuous fiber winding;During winding process, the bosses 5 are embedded in the grid rib inner layer 3 by hanging yarn, so that the mechanical interlocking of metal head 1 and composite cylinder is realized.

[0036] The underwater pressure shell adopts the idea of "divide and rule", and the metal head, the grid rib inner layer and the hoop winding layer bear bending, axial compression and ring pressure respectively, and the continuous fiber winding connection method is used, so that the stress is more evenly distributed in the fiber;And the connection form combining macro mechanical interlocking and micro interface interlocking is adopted, which improves the overall strength, stiffness, reliability and sealing of the structure, and at the same time ensures the lightweight level of the overall structure.

[0037] Further, as shown in the figure, Figure 4 The grid rib inner layer adopts diamond configuration or rectangular configuration structure form, and the rib angle and spacing are calculated by geometric relationship:

[0038]

[0039] w=s cos θ

[0040] In the formula, s is the circumferential spacing of boss, θ is the rib angle, i.e. the angle between rib and axial direction, n is the number of circumferential arrangement of boss, L is the length of composite shell, D is the inner diameter of shell, w is the rib spacing, i is the number of boss interval between upper and lower heads, i is 0-∞, θ=0° when i=0, i.e. rectangular configuration;When i is larger, θ is larger, i.e. diamond configuration. In the implementation process, the rib angle can be calculated by giving the number of bosses, or the number of bosses can be calculated by giving the rib angle.

[0041] Further, the composite cylinder adopts continuous fiber winding process, and the thickness t1 of the grid rib inner layer and the thickness t2 of the hoop winding layer are calculated according to the following axial buckling and external pressure buckling formula, respectively bearing the axial component (p / 3) and the hoop component (2p / 3) of external pressure load p;

[0042]

[0043] Where R is the inner radius of the shell, b is the rib width, μ1 and μ2 are the Poisson's ratios in the fiber direction and the direction perpendicular to the fiber, respectively, and E1 and E2 are the elastic moduli in the fiber direction and the direction perpendicular to the fiber, respectively.

[0044] Furthermore, the thickness h and length R1 of the annular flange can be determined according to a formula derived from force analysis;

[0045]

[0046] Rl=2t1

[0047] Furthermore, the shape of the boss can be a square prism, a cylinder, a square cone, a pyramid, etc., and the height, axial length, and circumferential width of the boss must be less than or equal to the thickness h of the annular flange; the edge of the boss can be sanded with sandpaper to set a circular chamfer to reduce the degree of stress concentration, and the chamfer radius is 1-3mm.

[0048] Furthermore, the inner layer of the mesh reinforcement adopts a continuous fiber wet winding process, such as Figure 5 As shown, during the winding process, the yarn is wound around the boss in the form of hanging yarn, and the winding order is "Z"-shaped, so that the metal head is inserted into the end of the inner layer of the grid rib through the boss, thereby realizing the connection between the metal head and the composite material cylinder.

[0049] Furthermore, a water-soluble lining can be provided when the inner layer of the grid rib is wound, and the material composition is polyethylene glycol: 30%-60%, diatomaceous earth filler: 10%-30%, calcium carbonate cosolvent: 5%-30%, cellulose powder toughening agent: 1%-10%, polyamide wax powder: 1%-5%, and stearic acid monoglyceride dispersant: 1%-8%.

[0050] Furthermore, the inner layer of the mesh reinforcement may be made of carbon fiber, glass fiber or other high-performance fiber materials, and the specific selection may depend on the use environment and load requirements.

[0051] Furthermore, the connection area between the connection structure and the composite material cylinder can be designed with structural features to enhance the connection, including: sandpaper polishing, sandblasting, laser etching, electrochemical corrosion, etc. The roughness of the connection interface must be greater than 1.5, and epoxy resin adhesive must be coated on the connection interface to improve the interface bonding strength and sealing.

[0052] Example 1

[0053] This embodiment provides a method for preparing a hemispherical metal head-composite cylinder heterogeneously connected underwater pressure hull, comprising the following steps:

[0054] (1) Calculate the external pressure load p to be 30 MPa, the shell inner diameter D to be 300 mm (radius R to be 150 mm), and the number of bosses arranged circumferentially n to be 24; calculate the boss circumferential spacing s using the formula:

[0055]

[0056] (2) The length L of the composite shell is 300 mm, i is 2, and the rib angle θ and rib spacing w are calculated:

[0057]

[0058] w=scosθ=38.0mm

[0059] (3) Calculate the thickness t1 of the inner layer of the composite mesh reinforcement and the thickness t2 of the hoop winding layer. The reinforcement width b is 4 mm. The fiber model used is T700. The matrix is ​​epoxy resin. The elastic modulus E1 and E2 of the T700 / epoxy resin composite material are 121 GPa and 73 GPa respectively, and the Poisson's ratio μ1 and μ2 are 0.35 and 0.44 respectively.

[0060]

[0061] The thicknesses t1 and t2 are rounded up, and finally t1 is 5 mm and t2 is 12 mm.

[0062] (4) The thickness of the annular flange is 2.5 mm ≤ h ≤ 17 mm. Taking h as 5 mm, calculate the length Rl of the flange:

[0063] Rl=2t1=10mm

[0064] (5) The boss is in a cubic configuration with a side length of 5 mm. The hemispherical metal head is processed according to the drawing. The flange and boss are machined using Q345R;

[0065] (6) The annular flange 4, boss 5 and wire groove 6 are polished with 60-grit sandpaper, and the surface roughness is 3.2;

[0066] (7) preparing a water-soluble lining, the material composition of which is polyethylene glycol: 30%-60%, diatomaceous earth filler: 10%-30%, calcium carbonate cosolvent: 5%-30%, cellulose powder toughening agent: 1%-10%, polyamide wax powder: 1%-5%, and stearic acid monoglyceride dispersant: 1%-8%; stirring at 100°C-120°C, placing the lining into a mold, and demolding after curing;

[0067] (8) Assemble the metal head on both sides of the water-soluble liner and apply epoxy resin adhesive to the annular flange 4, boss 5 and wire groove 6;

[0068] (9) The T700 carbon fiber prepreg tape is placed into the groove of the water-soluble inner liner, and the mesh rib structure is formed by hanging the yarn on the boss of the two metal end heads. Then, the water-soluble inner liner is removed by water washing;

[0069] (10) The hoop winding layer is wound outside the mesh rib structure, the winding angle is 90 degrees, the number of layers is 100, and the height of the winding layer is equal to the height of the end head;

[0070] (11) The prepared structure is cured, and the residual glue is cleaned to complete the connection of the metal end head and the composite cylinder and the preparation of the composite cylinder. The three-dimensional structure of the underwater pressure-resistant shell prepared finally is shown in Figure 6

[0071] Example 2

[0072] The hemispherical metal end head-composite cylinder heterogeneous connection underwater pressure-resistant shell of the present example is the same as that of Example 1 except that the number of bosses arranged circumferentially is 40, i.e. the interval is 23.6 mm arc length.

[0073] Example 3

[0074] The hemispherical metal end head-composite cylinder heterogeneous connection underwater pressure-resistant shell of the present example is the same as that of Example 1 except that the number of bosses arranged circumferentially is 80, i.e. the interval is 11.8 mm arc length.

[0075] Example 4

[0076] The hemispherical metal end head-composite cylinder heterogeneous connection underwater pressure-resistant shell of the present example is the same as that of Example 1 except that the inner layer of the mesh rib is rectangular in configuration, i.e. θ = 0°.

[0077] The underwater pressure-resistant shells of the above examples are subjected to external pressure buckling finite element analysis and strength analysis, and the results are shown in Table 1. As can be seen from the table, a reasonable number of bosses can reduce the stress concentration degree at the connection structure, affect the failure mode of the structure, and improve the failure load. Compared with the metal pressure-resistant shell and the composite pressure-resistant shell without mesh rib at the same level, weight reduction can be further achieved.

[0078] Table 1

[0079]

[0080]

[0081] ​The above merely describes preferred embodiments of the present application, and the present application is not limited to the above. Any person skilled in the art, without departing from the technical scope of the present application, can make many possible changes and modifications to the technical solutions of the present application, or modify equivalent embodiments with equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application, without departing from the technical scope of the present application, still falls within the protection scope of the technical solutions of the present application.

Claims

1. A hemispherical metal head-composite cylinder heterogeneously connected underwater pressure hull, characterized in that: It includes two hemispherical metal heads, a connecting structure and a composite material cylinder. The metal head and the connecting structure are manufactured in one piece. The connecting structure is provided with an annular flange, and a number of bosses are arranged at equal intervals around the annular flange. The composite material cylinder comprises an inner layer of mesh reinforcement and an annular winding layer. The inner layer of mesh reinforcement is connected to the metal head through the connecting structure, and the outer side of the inner layer of mesh reinforcement is an annular winding layer. The inner layer of mesh reinforcement and the annular winding layer are both made by continuous fiber winding. During the winding process, the inner layer of mesh reinforcement is embedded in the inner layer of mesh reinforcement by hanging yarn, thereby realizing mechanical interlocking of the metal head and the composite material cylinder.

2. The hemispherical metal head-composite cylinder heterogeneously connected underwater pressure hull according to claim 1 is characterized in that: The inner layer of the grid ribs adopts a diamond configuration or a rectangular configuration structure, and the rib angles and spacing are calculated based on the geometric relationship: w=scosθ Where s is the circumferential spacing of the bosses, θ is the rib angle, n is the number of circumferential bosses, L is the length of the composite shell, D is the inner diameter of the shell, w is the rib spacing, and i is the number of boss intervals between the upper and lower heads. i ranges from 0 to ∞. When i = 0, θ = 0°, which is a rectangular configuration. When i increases, θ increases, which is a diamond configuration.

3. The hemispherical metal head-composite cylinder heterogeneously connected underwater pressure hull according to claim 2 is characterized in that: The thickness t1 of the inner layer of the mesh reinforcement and the thickness t2 of the hoop winding layer are calculated according to the following axial compression buckling and external pressure buckling formulas, respectively bearing the axial component and hoop component of the external pressure load p; Where R is the inner radius of the shell, b is the rib width, μ1 and μ2 are the Poisson's ratios in the fiber direction and the direction perpendicular to the fiber, respectively, and E1 and E2 are the elastic moduli in the fiber direction and the direction perpendicular to the fiber, respectively.

4. The hemispherical metal head-composite cylinder heterogeneously connected underwater pressure hull according to claim 3 is characterized in that: The thickness h and length R1 of the annular flange are determined according to the formula derived from the force analysis; Rl=2t1.

5. The hemispherical metal head-composite cylinder heterogeneously connected underwater pressure hull according to claim 1 is characterized in that: The shape of the boss is a square column, a cylinder, a square cone or a pyramid, and the height, axial length and circumferential width of the boss must be less than or equal to the thickness of the annular flange.

6. The hemispherical metal head-composite cylinder heterogeneously connected underwater pressure hull according to claim 1 is characterized in that: The edge of the boss is sanded with sandpaper to set a circular chamfer to reduce stress concentration, and the chamfer radius is 1-3 mm.

7. The hemispherical metal head-composite cylinder heterogeneously connected underwater pressure hull according to claim 1 is characterized in that: The inner layer of the mesh reinforcement adopts a continuous fiber wet winding process. During the winding process, the yarn is wound around the boss in the form of hanging yarn, and the winding order is "Z"-shaped, so that the metal head is inserted into the end of the inner layer of the mesh reinforcement through the boss, thereby realizing the connection between the metal head and the composite material cylinder.

8. The hemispherical metal head-composite cylinder heterogeneously connected underwater pressure hull according to claim 1 is characterized in that: The water-soluble lining is provided when the inner layer of the grid reinforcement is wound. The material composition is polyethylene glycol: 30%-60%, diatomaceous earth filler: 10%-30%, calcium carbonate cosolvent: 5%-30%, cellulose powder toughening agent: 1%-10%, polyamide wax powder: 1%-5%, and stearic acid monoglyceride dispersant: 1%-8%.

9. The hemispherical metal head-composite cylinder heterogeneously connected underwater pressure hull according to claim 1 is characterized in that: The connection area between the connection structure and the composite material cylinder is designed to enhance the structural characteristics of the connection, including: sandpaper polishing, sandblasting, laser etching, electrochemical corrosion, the connection interface roughness must be greater than 1.5, and epoxy resin adhesive is coated on the connection interface to improve the interface bonding strength and sealing.

10. The hemispherical metal head-composite cylinder heterogeneously connected underwater pressure hull according to claim 1 is characterized in that: The metal head, mesh reinforcement inner layer and hoop winding layer of the underwater pressure hull bear bending, axial pressure and hoop pressure respectively, and adopt a continuous fiber winding connection method to make the stress more evenly distributed in the fiber.

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