Multistage confining pressure cylindrical shell structure

Abstract

The invention discloses a multi-stage confining pressure cylindrical shell structure, and belongs to the field of pressure-resistant structures of underwater vehicles. The structure comprises an end flange, a skin, a cap-shaped main reinforced rib, a spiral secondary reinforced rib and a powder discharging hole, the end flange transits axial stress; the skin is a main load-bearing structure; the cap-shaped main reinforcing ribs are distributed at equal intervals, annular rigidity is provided, and the overall buckling load of the structure is effectively improved. The spiral secondary reinforcing ribs are evenly distributed between the skin and the cap-shaped main reinforcing ribs, concentrated stress distribution near the cap-shaped main reinforcing ribs is reduced, local bulging is resisted, and strength damage is restrained. The multi-stage confining pressure cylindrical shell structure is uniform in stress and high in confining pressure bearing efficiency, the defects that a traditional metal confining pressure structure is insufficient in large diving depth bearing performance and the like are overcome, and design and application of a large diving depth underwater vehicle pressure-resistant structure are facilitated.

Description

Technical Field

[0001] The invention belongs to the technical field of submersible pressure-resistant structures, and in particular relates to a multi-stage confining pressure cylindrical shell structure. Background Art

[0002] As the core component of a submersible, the confining pressure hull is usually made of a steel ring-ribbed cylindrical shell, which accounts for about 1 / 4 to 1 / 2 of the weight of the entire submersible structure, providing a reliable and safe space for instruments, equipment and personnel. In addition to meeting basic mechanical requirements, its design also has strict weight restrictions to meet the layout requirements of instruments and equipment and other loads; the development of deep-sea exploration capabilities requires submersibles to have large diving depths and multiple load capabilities. Under the traditional confining pressure hull structure scheme, the contradiction between the pressure resistance requirements of large diving depths and the limited structural weight requirements has become increasingly prominent. How to meet the load-bearing requirements of large diving depths without significantly increasing the structural weight is a difficult problem currently faced by the design of confining pressure hulls. The use of 3D printing technology can break through the limitations of traditional welding processes on the structural form of confining pressure hulls, and manufacture more complex multi-stage confining pressure structures with higher load-bearing efficiency.

[0003] The multi-level structure design is inspired by bionics. For example, bamboo joints and bones have a variety of microstructures, and different structures have different functions in the evolution process. The multi-level reinforced ribs are designed to resist different forms of buckling. The main reinforced ribs increase the overall bending stiffness and the overall buckling load, and the secondary reinforced ribs are used to reduce the stress concentration and local buckling caused by uneven stress distribution. Due to the complexity of the multi-level structure, the traditional processing technology is difficult to produce and the labor cost is high. At present, there is no relevant design of the metal multi-level reinforced rib structure in the pressure hull design. Summary of the invention

[0004] The present invention provides a multi-stage confining pressure cylindrical shell structure, which can improve the disadvantage of low efficiency of traditional pressure-resistant structures and achieve efficient bearing performance of complex structures.

[0005] To achieve the above objectives, the present invention adopts the following technical solutions:

[0006] A multi-stage confining cylindrical shell structure comprises an end flange, a skin, a hat-shaped main reinforced rib, a spiral secondary reinforced rib, and a powder discharge hole; the hat-shaped main reinforced ribs are evenly spaced on the inner side of the skin, and the spacing is obtained by optimizing the structural load efficiency; the spiral secondary reinforced ribs are evenly distributed between the hat-shaped main reinforced ribs and the skin, close to the inner side of the skin, and the spiral secondary reinforced ribs are interrupted at the overlapped parts of the spiral secondary reinforced ribs and the hat-shaped main reinforced ribs; the end flanges are located at both ends of the structure, and are thickened from the skin inwards, and the end flanges and the ends of the end hat-shaped main reinforced ribs adopt a slope transition to make the stress evenly transition to the main bearing structure; the powder discharge holes are arranged at 90 degrees on both sides of the hat-shaped main reinforced ribs.

[0007] The length l, thickness t, radius R of the multi-stage confining cylindrical shell structure, and the number of the hat-shaped main stiffening ribs N s Evenly distributed on the inner side of the skin, with a spacing of l s =l / N s The corners of the hat-shaped main reinforced ribs are chamfered for transition to reduce stress concentration effects, reduce the risk of damage caused by uneven stress transfer and facilitate manufacturing;

[0008] The hat-shaped main stiffening rib is designed according to three parts: a bottom brim, an inclined web and a top flange. The bottom brim is directly connected to the skin, and the inclined web is connected by a chamfer transition method on the basis of the brim. Finally, the inclined web is connected to the top flange to form the hat-shaped main stiffening rib. The bottom brim transfers the skin stress and homogenizes the stress distribution. The inclined web provides bending stiffness. The top flange enhances the bending stiffness, constrains the deformation of the inclined web, and ensures the continuity of 3D printing.

[0009] The hat-shaped main reinforcing rib and the skin are designed with an angle of α=40°~45°; the hat-shaped reinforcing rib thickness t s =0.5t~1.5t, the length of the bottom brim is l b =max(0.1l b ~0.15l b , t s / sinα), inclined web length l f =0.25l s ~0.7l s , top flange length l t =0.05l s ~0.12l s , of which 0.35l s <(l t +2l f cosα)<0.4l s , in order to improve the material load efficiency while meeting the process requirements, the corners of the hat-shaped main reinforced ribs are chamfered to reduce the stress concentration effect;

[0010] The angle of the spiral secondary reinforcement rib β is ±60°~75°, and the number of spiral ribs N p =30~70, the edge part of the spiral secondary reinforced rib adopts chamfer transition to facilitate manufacturing.

[0011] Each hat-shaped main reinforcing rib has 4 powder discharge holes, and the powder discharge holes between different reinforcing ribs are arranged at equal intervals.

[0012] The above-mentioned multi-stage confining pressure cylindrical shell structure is manufactured using 3D printing technology. Before 3D printing, the structure is chamfered and the shell is printed vertically without any external support throughout the process.

[0013] Beneficial effects: The present invention provides a multi-stage confining cylindrical shell structure, which is different from the traditional single-stage reinforced rib pressure-resistant structure. The present invention adopts a multi-stage reinforced rib design, and the end flange transitions the axial stress, so that the axial stress is evenly transitioned to the main load-bearing structure, reducing the risk of end damage; the skin is the main load-bearing structure; the hat-shaped main reinforced ribs are evenly distributed to provide circumferential stiffness, effectively improve the overall buckling load of the structure, and improve the material load efficiency; the spiral secondary reinforced ribs are evenly distributed between the skin and the hat-shaped main reinforced ribs, reducing the concentrated stress distribution near the hat-shaped main reinforced ribs, and the introduction of spiral secondary reinforced ribs enhances the structure's anti-buckling ability, effectively widens the structural optimization form, makes the structure more efficient, resists local bulging and inhibits strength damage; in addition, the structural powder discharge hole design solves the problem of powder accumulation in the closed structure, and the discrete distribution of the powder discharge holes avoids stress concentration, and the force is more uniform, providing a basis for subsequent heat treatment. The invention has reasonable structural optimization, uniform stress, high pressure resistance, good product stability and fast manufacturing time; the multi-stage confining pressure cylindrical shell structure of the invention has uniform stress and high confining pressure bearing efficiency, which solves the shortcomings of the traditional metal confining pressure configuration such as insufficient deep diving bearing performance, and is beneficial to the design and application of the pressure-resistant structure of deep diving submersibles. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of a multi-stage confining pressure cylindrical shell structure manufactured by 3D printing technology in an embodiment of the present invention;

[0015] Figure 2 This is a 1 / 4 cross-sectional view of a multi-stage confining pressure cylindrical shell structure manufactured by 3D printing technology in an embodiment of the present invention;

[0016] Figure 3 This is a front view of the hat-shaped main stiffening rib of the multi-stage confining pressure cylindrical shell structure manufactured by 3D printing technology in an embodiment of the present invention;

[0017] Figure 4 This is a front view of a single hat-shaped main stiffening rib of a multi-stage confining pressure cylindrical shell structure manufactured by 3D printing technology in an embodiment of the present invention;

[0018] Figure 5 This is a top view of a single hat-shaped main stiffening rib of a multi-stage confining pressure cylindrical shell structure manufactured by 3D printing technology in an embodiment of the present invention;

[0019] Figure 6 This is a front view of the powder discharge hole of the multi-stage confining pressure cylindrical shell structure manufactured by 3D printing technology in an embodiment of the present invention;

[0020] Figure 7 This is a top view of the powder discharge holes of the multi-stage confining pressure cylindrical shell structure manufactured by 3D printing technology in an embodiment of the present invention;

[0021] Figure 8This is a cross-sectional view of a flange of a multi-stage confining pressure cylindrical shell structure manufactured by 3D printing technology in an embodiment of the present invention;

[0022] Fig. 9 This is a schematic diagram of the composition of the hat-shaped main reinforcing ribs in an embodiment of the present invention;

[0023] Fig.10 Schematic diagram of spiral secondary reinforcing ribs in an embodiment of the present invention;

[0024] Fig.11 This is a diagram showing the arrangement of the powder discharge ports in an embodiment of the present invention;

[0025] In the figure, 1-end flange, 2-spiral secondary reinforcing rib, 3-hat-shaped main reinforcing rib, 4-powder discharge hole, 5-skin. DETAILED DESCRIPTION

[0026] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments:

[0027] like Figure 1 As shown, a multi-stage confining cylindrical shell structure includes end flanges, skin, hat-shaped main reinforcing ribs, spiral secondary reinforcing ribs, and powder discharge holes; the hat-shaped main reinforcing ribs are evenly spaced on the inner side of the skin, and the spacing is obtained by optimizing the structural load efficiency; the spiral secondary reinforcing ribs are evenly distributed between the hat-shaped main reinforcing ribs and the skin, close to the inner side of the skin, and the spiral secondary reinforcing ribs are interrupted at the overlapped parts of the spiral secondary reinforcing ribs and the hat-shaped main reinforcing ribs; the end flanges are located at both ends of the structure, and are thickened from the skin inwards. The end flanges and the end of the hat-shaped main reinforcing ribs are connected by the The slope transition allows the stress to be evenly transitioned to the main bearing structure; the powder discharge holes are arranged at 90° on both sides of the hat-shaped main reinforcing ribs; the end flange can evenly transition to the main structure when subjected to axial load, the skin is the main load-bearing structure, and the hat-shaped main reinforcing ribs mainly improve the overall bending stiffness to resist overall deformation; the spiral secondary reinforcing ribs mainly reduce the stress concentration effect between the skin and the hat-shaped main reinforcing ribs, and resist local buckling; the powder discharge holes are on both sides of the main reinforcing ribs to remove the powder on the inner side of the main reinforcing ribs and avoid sintering problems caused by subsequent heat treatment.

[0028] The number of the hat-shaped main reinforcing ribs is N s Evenly distributed on the inner side of the skin, with a spacing of l s =l / N s The corners of the hat-shaped main reinforced ribs are chamfered for transition to reduce stress concentration effects, reduce the risk of damage caused by uneven stress transfer and facilitate manufacturing;

[0029] The hat-shaped main reinforcing rib is designed as three parts: the bottom brim, the inclined web, and the top flange. The bottom brim transfers the skin stress and evens out the stress distribution; the inclined rib provides bending stiffness; the top flange enhances the bending stiffness, constrains the deformation of the inclined rib, and ensures the continuity of 3D printing. According to the structural optimization results and structural rationality requirements, the angle between the hat-shaped main reinforcing rib and the skin is designed to be α = 40° ~ 45°; the thickness of the hat-shaped reinforcing rib is t s =0.5t~1.5t, t is the thickness of the skin; the length of the bottom brim is l b =max(0.1 b ~0.15l b , t s / sinα); inclined web length l f =0.25l s ~0.7l s ; Top flange length l t =0.05l s ~0.12l s , of which 0.35l s <(l t +2l f cosα)<0.4l s , in order to improve the material load efficiency while meeting the process requirements, the corners of the hat-shaped main reinforced ribs are chamfered to reduce the stress concentration effect;

[0030] The angle of the spiral secondary reinforcement rib β is ±60°~75°, and the number of spiral ribs N p =30~70, the edge part of the spiral secondary reinforced rib adopts chamfer transition to facilitate manufacturing.

[0031] Each hat-shaped main reinforcing rib has 4 powder discharge holes, and the powder discharge holes between different reinforcing ribs are arranged at equal intervals.

[0032] The above-mentioned multi-stage confining pressure cylindrical shell structure is prepared using 316L powder and manufactured using selective laser melting technology. The structure is integrally formed and then heat treated to remove residual stress during the printing process. The design parameters of the metal hat-shaped multi-stage reinforced cylindrical shell are shown in Table 1. Finally, the size is scanned and the model is reconstructed for subsequent analysis. The final finite element test result is 9.5 MPa. When the actual underwater test is 7 MPa, the structure has no obvious deformation, and the overall structure partially enters the critical plastic state without any signs of water leakage.

[0033] Table 1 Design parameters of metal hat-shaped multi-stage reinforced cylindrical shell

[0034]

[0035] The above are only preferred embodiments of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A multi-stage confining pressure cylindrical shell structure, characterized in that: It includes end flange, skin, main stiffening ribs and secondary stiffening ribs; the main stiffening ribs are evenly distributed on the inner side of the skin; the secondary stiffening ribs are evenly distributed between the main stiffening ribs and the skin, close to the inner side of the skin, the secondary stiffening ribs are interrupted at the overlapped parts with the main stiffening ribs; the end flanges are located at both ends of the structure, thickened from the skin inwards, and the end of the end flange and the end of the main stiffening rib adopts a slope transition.

2. The multi-stage confining pressure cylindrical shell structure according to claim 1 is characterized in that: The spacing between the main reinforcing ribs is l s =l / N s , l is the length of the multi-stage confining pressure cylindrical shell structure, N s The number of main stiffening ribs.

3. The multi-stage confining pressure cylindrical shell structure according to claim 2 is characterized in that: The main reinforcing rib is a hat-shaped main reinforcing rib, which includes a bottom brim, an inclined web, and a top flange. The bottom brim is directly connected to the skin, and the inclined web is connected to the top flange by a chamfered transition method on the basis of the bottom brim.

4. The multi-stage confining pressure cylindrical shell structure according to claim 3 is characterized in that: The angle between the hat-shaped main reinforcing rib and the skin is α=40°~45°.

5. The multi-stage confining pressure cylindrical shell structure according to claim 3 or 4, characterized in that: The thickness of the hat-shaped reinforcement rib is t s =0.5t~1.5t, the bottom brim length is l b =max(0.1lb~0.15l b , t s / sinα), inclined web length l f =0.25l s ~0.7l s , top flange length l t =0.05l s ~0.12l s , of which 0.35l s <(l t +2l f cosα)<0.4l s .

6. The multi-stage confining pressure cylindrical shell structure according to claim 3 or 4, characterized in that: The corners of the hat-shaped main reinforcing ribs are chamfered for transition.

7. The multi-stage confining pressure cylindrical shell structure according to claim 1, characterized in that: The secondary reinforcing ribs are spiral rectangular secondary reinforcing ribs, and the number of the spiral rectangular secondary reinforcing ribs is N. p =30~70.

8. The multi-stage confining pressure cylindrical shell structure according to claim 7, characterized in that: The angle of the spiral rectangular secondary reinforcing rib β is ±60° to 75°; the edge portion of the spiral secondary reinforcing rib adopts chamfer transition.

9. The multi-stage confining pressure cylindrical shell structure according to claim 1 or 2, characterized in that: The main reinforcing ribs are provided with powder discharge holes, which are arranged at 90° offset on both sides of the main reinforcing ribs; the powder discharge holes between different reinforcing ribs are arranged at equal intervals.

10. The multi-stage confining pressure cylindrical shell structure according to claim 1, characterized in that: The multi-stage confining pressure cylindrical shell structure is manufactured using 3D printing technology. Before 3D printing, the structure is chamfered and the shell is printed vertically without any external support throughout the process.

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