WO2024000760A1

WO2024000760A1 - Stiffened corrugated egg-shaped pressure hull and machining method therefor

Info

Publication number: WO2024000760A1
Application number: PCT/CN2022/113294
Authority: WO
Inventors: 张建; 程鹏; 汤寅辉; 唐文献; 展铭; 李永胜; 王纬波
Original assignee: 江苏科技大学
Priority date: 2022-06-27
Filing date: 2022-08-18
Publication date: 2024-01-04
Also published as: CN115195934B; KR20240064643A; CN115195934A

Abstract

A stiffened corrugated egg-shaped pressure hull and a machining method therefor, relating to the technical field of deep-submergence vehicles. The stiffened corrugated egg-shaped pressure hull comprises a large-end flat closure plate (5), a small-end flat closure plate (1), longitudinal stiffeners (2), a ring stiffener (3) and corrugated egg-shaped shell pieces (4). Machining steps comprise: determining a stiffener contour equation of the longitudinal stiffeners (2); designing the cross section of the stiffened corrugated egg-shaped pressure hull; according to a shell piece exploded view, scribing, and cutting and blanking; bending twelve shell pieces; determining the size of the longitudinal stiffeners (2); machining the longitudinal stiffeners (2); assembling and welding the bent shell pieces and the longitudinal stiffeners (2); assembling and welding the flat closure plates at the two ends; machining the ring stiffener (3); assembling and welding the ring stiffener (3) on the pressure hull, so that the machining of the stiffened corrugated egg-shaped pressure hull is completed. The use of the corrugated egg-shaped pressure hull structure reduces the machining difficulty, and guarantees the safety; a variable-thickness stiffener structure is used, and the longitudinal stiffeners (2) and the ring stiffener (3) are welded on the outer side the egg-shaped pressure hull, so that the compression resistance and the material utilization rate are both improved; the overall quality of the shell is reduced while the strength and rigidity of the pressure hull are guaranteed, the costs are reduced, and machining and manufacturing are facilitated.

Description

A ribbed corrugated egg-shaped pressure-resistant shell and its processing method

Technical field

The invention belongs to the technical field of deep-sea submersibles, and relates to a pressure-resistant device and a processing method for a deep-sea submersible. More specifically, it relates to a ribbed corrugated egg-shaped pressure-resistant shell and a processing method thereof.

Background technique

Submersibles are important equipment for ocean exploration and deep-sea scientific research. As an important part of submersibles, pressure-resistant equipment plays a role in ensuring the normal operation of internal equipment and the health and safety of personnel during the dive. Its weight accounts for 10% of the total weight of the submersible. 1/4-1/2. The design of pressure-resistant equipment has an important impact on the safety, maneuverability, space utilization and human-machine environment of the submersible. The pressure hulls of deep-sea submersibles are mostly spherical structures, which have the advantages of high strength, good stability, low buoyancy coefficient, and high material utilization. However, they have low space utilization, poor hydrodynamic properties, are quite sensitive to defects, and are difficult to process and manufacture. , unable to optimally coordinate the safety, carrying capacity and human-machine environment characteristics of the submersible.

The patent number is ZL201510073803.4 (a deep-sea bionic pressure-resistant shell), which proposes a conceptual egg-shaped bionic pressure-resistant shell, and points out that the egg-shaped bionic shell can comprehensively coordinate strength, stability, space utilization, It is an excellent bionic prototype with features such as streamlined shape, but ordinary egg-shaped pressure-resistant shells are prone to yielding during deep-sea operations, and the patent does not provide specific processing methods. The application number is 202210071068.3 (A laminated egg-shaped pressure-resistant shell and its processing method). A design of a laminated egg-shaped pressure-resistant shell is proposed. Although the pressure-resistant capacity of the shell is improved, it also increases the pressure to a large extent. improves the overall quality of the pressure shell. To sum up, there are finally three problems: 1. The traditional egg-shaped pressure-resistant shell is an ideal egg-shaped structure, which is prone to buckling under the action of hydrostatic pressure, has many failure factors, is difficult to process, and has low safety performance. ; 2. The pressure resistance of the traditional single-layer egg-shaped structure design has been improved compared to the cylindrical, conical and annular shapes, but the effect is still not significant enough to meet the needs of deep-sea operations at greater depths; 3. In order to improve the pressure-resistant shell To improve the pressure resistance and service life, we often design multi-layer egg-shaped pressure shells or increase the thickness of the shell, which results in a greatly increased overall mass of the pressure shell, making it difficult to process and higher in cost.

Therefore, in response to the above problems, on the basis of existing research, a ribbed corrugated egg-shaped pressure-resistant shell device with a simple, reliable structure and easy manufacturing is important for improving the mechanical distribution and pressure resistance of the shell and reducing manufacturing costs. significance.

Contents of the invention

Purpose of the invention: The purpose of the invention is to provide a ribbed corrugated egg-shaped pressure-resistant shell and a processing method thereof.

Technical solution: a ribbed corrugated egg-shaped pressure-resistant shell device according to the present invention, including a small-end head plate (1) at the upper end and a large-end head plate (5) at the lower end;

A corrugated egg sheet body (4) is installed between the small end head plate (1) and the big end head plate (5). (5), several longitudinal ribs (2) are installed at equal intervals on the outside of the corrugated egg sheet body (4);

Ring ribs (3) for connecting the longitudinal ribs (2) are installed at the middle and lower ends of several of the longitudinal ribs (2).

Further, the number of longitudinal ribs (2) is at least 12.

Further, several of the longitudinal ribs (2) are welded to the small end head plate (1) and the big end head plate (5).

Furthermore, the small-end head plate (1) and the large-end head plate (5) each include a central end placed inside, and at least 12 extension ends are evenly distributed around the center end.

Further, a method for processing a ribbed corrugated egg-shaped pressure-resistant shell device, the specific operating steps are as follows:

Step 1. Determine the rib profile equation of longitudinal rib 2, in which the rib profile equation of longitudinal rib 2 is designed using the N-R equation;

Step 2. Design the ribbed corrugated egg-shaped pressure shell cross-section;

Step 3. Draw lines, cut and blank according to the shell expansion diagram;

Step 4. Bend the 12-piece shell;

Step 5. Determine the size of the longitudinal rib 2 according to the mechanical formula;

Step 6. Process the longitudinal rib 2 according to the longitudinal rib 2 drawing;

Step 7. Assemble and weld the 12-piece bent shells and the longitudinal ribs 2; weld a piece of bent shell on both sides of each longitudinal rib, and the 12-piece shells and 12 longitudinal ribs are alternately welded into a complete case;

Step 8. Assemble and weld the head plates at both ends; cut out the upper and lower head plates according to the outline of the schematic diagram, and then weld them to the complete welded shell;

Step 9: Process the ring rib 3 according to the ring rib 3 drawing;

Step 10. Assemble and weld the ring ribs 3 on the pressure shell; then weld the processed ring ribs 3 on the ribbed corrugated egg-shaped pressure shell one by one; the processing of the ribbed corrugated egg-shaped pressure shell is completed. .

Beneficial effects: Compared with the prior art, the present invention has the following characteristics: 1. It adopts a corrugated egg-shaped pressure-resistant shell structure, and each shell bears tensile stress, so the pressure-resistant structure will not buckle and yield will become the only failure factors, reducing processing difficulty and ensuring safety; 2. Using a thickened rib structure, using longitudinal ribs and ring ribs welded to the outside of the egg-shaped pressure shell, the compression resistance and material utilization are improved; 3. , while ensuring the strength and stiffness of the pressure shell, the overall mass of the shell is reduced, the cost is reduced, and it is easy to process and manufacture.

Description of drawings

Figure 1 is a schematic structural diagram of the ribbed corrugated egg-shaped pressure-resistant shell in the present invention;

Figure 2 is a schematic diagram of the contour equation of ribbed corrugated eggshell ribs in the present invention;

Figure 3 is a schematic cross-sectional design diagram of the ribbed corrugated egg-shaped pressure-resistant shell in the present invention;

Figure 4 is a schematic view of the ribbed corrugated egg-shaped pressure-resistant shell body of the present invention unfolded;

Figure 5 is a schematic diagram of the ribbed corrugated egg-shaped pressure-resistant shell body after bending in the present invention;

Figure 6 is a schematic cross-sectional view of the longitudinal ribs of the ribbed corrugated egg-shaped pressure-resistant shell of the present invention;

Figure 7 is a schematic diagram of the longitudinal rib structure of the ribbed corrugated egg-shaped pressure-resistant shell in the present invention;

Figure 8 is a schematic diagram of the ring rib structure of the ribbed corrugated egg-shaped pressure-resistant shell in the present invention;

Figure 9 is a schematic diagram of the structure of the two ends of the ribbed corrugated egg-shaped pressure-resistant shell of the present invention;

Figure 10 is a schematic diagram of the completed welding of the ribbed corrugated egg-shaped pressure shell of the present invention;

Figure 11 is a schematic diagram of the completion of welding of the two ends of the ribbed corrugated egg-shaped pressure-resistant shell of the present invention;

Figure 12 is a processing and production flow chart of the present invention;

Figure 13 is the LPF curve of ordinary eggshell;

Figure 14 is the LPF curve of ribbed corrugated eggshells in the present invention;

Figure 15 is a comparison chart of the simulation results of ordinary eggshells and ribbed corrugated egg-shaped pressure-resistant shells;

In Figure 1, 1 is the flat plate with the small end head, 2 is the longitudinal rib, 3 is the ring rib, 4 is the corrugated egg sheet body, and 5 is the flat plate with the big end head.

Detailed ways

In order to explain the technical solution of the present invention more clearly, the technical solution of the present invention will be further described in detail below in conjunction with the accompanying drawings:

As shown in Figure 1, it is a ribbed corrugated egg-shaped pressure-resistant shell device of the present invention, including a small end head plate 1, a longitudinal rib 2, an annular rib 3, a corrugated egg sheet body 4, and a large end head plate 5 .

Among them, (1), shell shape design

The rib contour equation of the ribbed corrugated egg-shaped pressure shell is designed using the N-R equation, and the busbar equation is shown in Equation (1):

Among them, f(x) is the rib outline equation of the corrugated eggshell; L is the long axis of the egg-shaped pressure shell, and B is the short axis of the egg-shaped pressure shell. The schematic diagram of the rib outline equation of the ribbed corrugated eggshell is shown in Figure 2 shown;

Under the premise of establishing the rib profile, the cross-sectional profile design is carried out. The schematic diagram is shown in Figure 3. First, take a circle with a radius of R ₁ , inscribe the regular dodecagon in the circle, and inscribe the regular dodecagon in the circle. The central angle of the circle is θ, and the side length of the regular dodecagon inscribed in the circle is a, then the following formula is satisfied:

a＝2R ₁ sin(π/n)＝2R ₁ sin(π/12) (3)

Among them, θ is the central angle subtended by the regular dodecagon inscribed in the circle, R ₁ is the radius of the circle, and a is the side length of the regular dodecagon inscribed in the circle;

Then use the side length of the regular dodecagon as the chord and β as the central angle to draw an arc. The center O ₂ corresponding to this arc is on a circle with a radius of R _2. β and R ₂ satisfy the following formula:

The cross-sectional profile design of the ribbed corrugated egg-shaped pressure shell is completed, and then the profile is scanned through the busbar to form a complete shell; the three-dimensional modeling software SolidWorks is used to flatten each piece of the corrugated eggshell, and its structural diagram is shown in Figure 4 , the bent sheet is shown in Figure 5.

(2), Longitudinal rib 2 design

Determine the size of the longitudinal ribs according to the mechanical formula; when designing the ribs, due to the limitations of a variety of objective factors, when selecting the cross section of the rib, not only the required section modulus should be considered, but also the cross-sectional area should be minimized. While ensuring the strength and stiffness of the egg-shaped pressure shell device, the overall mass is reduced to the greatest extent; the cross-section diagram of the longitudinal ribs of the ribbed corrugated egg-shaped pressure shell is shown in Figure 6; the cross-sectional width of the rib is constant b, The height is the variable h ₁ , and the allowable stress σ _w is required to remain unchanged. Considering the bending moment design, each cross section must fit the equation:

σ _w =M/S (6)

M is the bending moment, S is the section modulus; for a rectangle,

S＝bh ₁ ² /6 (7)

And M=Px (8)

Then σ _w =6Px/(bh ₁ ² ) (9)

The height at any other section is:

Draw the structure of the longitudinal rib according to the designed longitudinal rib size. The structural diagram of the longitudinal rib 2 of the ribbed corrugated egg-shaped pressure shell is shown in Figure 7;

(3), ring rib 3 design

Draw the structure of the ring rib 3 according to the designed size of the ring rib 3. The schematic diagram of the ring rib 3 structure of the ribbed corrugated egg-shaped pressure-resistant shell is shown in Figure 8;

(4), Head plate design

According to the design dimensions of the corrugated eggshell cross-sectional profile, draw the flat head structures at both ends. The schematic diagram of the head structures at both ends of the ribbed corrugated egg-shaped pressure-resistant shell is shown in Figure 9;

A processing method for a ribbed corrugated egg-shaped pressure-resistant shell, including the following steps:

The first step: Determine the longitudinal rib 2 rib contour equation; the longitudinal rib 2 rib contour equation is designed using the N-R equation, and its schematic diagram is shown in Figure 2;

Step 2: Design the cross-section of the ribbed corrugated egg-shaped pressure shell; each design parameter has been given in the shell shape design. The cross-section design diagram of the ribbed corrugated egg-shaped pressure shell is shown in Figure 3;

Step 3: Draw lines, cut and blank according to the shell expansion diagram; the ribbed corrugated egg-shaped pressure-resistant shell body expansion diagram is shown in Figure 4;

Step 4: Bending the 12-piece shell; use a bending machine to bend the pieces unfolded in the previous step. The schematic diagram after bending is shown in Figure 5.

Step 5: Determine the size of the longitudinal rib 2 according to the mechanical formula; determine the size of the longitudinal rib according to the above formula for the design of the longitudinal rib 2. The schematic diagram of the rib section of the longitudinal rib 2 is shown in Figure 6;

Step 6: Process the longitudinal rib 2 according to the drawing of the longitudinal rib 2; the structural diagram of the longitudinal rib of the ribbed corrugated egg-shaped pressure shell is shown in Figure 7;

Step 7: Assemble and weld the bent sheet body and the longitudinal ribs 2; weld a bent shell on both sides of each

longitudinal rib

2, and 12 shells and 12 longitudinal ribs 2 are alternately welded into a complete The schematic diagram of the completed shell welding of the ribbed corrugated egg-shaped pressure-resistant shell is shown in Figure 10;

Step 8: Assemble and weld the flat plates at both ends of the head; the structural diagram of the two ends of the ribbed corrugated egg-shaped pressure shell is shown in Figure 9. Cut out the upper and lower flat plates according to the outline of the schematic diagram, and then weld them to the top respectively. On the complete shell welded in one step, the schematic diagram of the welding of the two ends of the ribbed corrugated egg-shaped pressure shell is shown in Figure 11;

Step 9: Process the ring rib 3 according to the ring rib 3 drawing; draw a ribbed corrugated egg-shaped pressure shell ring rib structural diagram according to the size of the ring 3, as shown in Figure 8, and then process the ring rib.

Step 10: Assemble and weld the ring ribs 3 to the pressure shell; weld the ring ribs processed in the previous step to the egg-shaped pressure shell one by one;

Finally, the processing of a ribbed corrugated egg-shaped pressure-resistant shell was completed; the processing and production flow chart is shown in Figure 12;

According to the above processing method, determine the size and calculate the bearing capacity of the ribbed corrugated egg-shaped pressure shell.

Step1: Establish a numerical geometric model; according to the busbar in Figure 2, take the long axis of the egg-shaped pressure shell L = 400mm, B = 276mm, and select the average wall thickness of the shell for thickness assignment. The average thickness is 1mm, which is an ordinary eggshell. The finite element model; on the above basis, add 12 longitudinal ribs and 1 ring rib to establish the finite element model of ribbed corrugated eggshell. The specific model parameters are shown in Table 1.

Table 1 Model parameters

Step2: Mesh division; the total number of mesh divisions for the ordinary eggshell model is 15791, all of which are quadrilateral meshes; the total number of mesh divisions for the ribbed corrugated eggshell model is 23772, the number of quadrilateral meshes is 22856, and the number of triangular meshes is 916;

Step3: Set material parameters; by default the shell and ribs belong to the same material, set the elastic modulus of the material to 180119MPa and Poisson's ratio to 0.3;

Step 4: Set the nonlinear buckling analysis parameters of the two models; use the improved Riks method in the commercial software ABAQUS for analysis, and use the finite element method to conduct geometric nonlinear elastic analysis of ordinary egg-shaped and ribbed corrugated eggshells. The numerical analysis refers to The European standards (European Norms, 2009) and Chinese standards (China Classification Society, 2018) are adopted; the calculation parameters of the improved Riks method are set as follows: the initial arc length increment of the static equilibrium path is 0.05, and the number of arc length increment steps is 200, the minimum arc length increment is 1e-5, the maximum arc length increment is 0.1, the load limit is set to 20, the solution parameters of numerical analysis are shown in Table 2.

Table 2 Solution parameters of numerical analysis

Step5: Set boundary conditions and loads; use a fully fixed positioning method for the upper head plate, and apply a 1MPa load evenly on the outer surfaces of the two models;

Step6: Obtain the bearing capacity of ordinary eggshells and ribbed corrugated eggshells; after setting according to the above steps, submit the analysis job; after the analysis is completed, extract the LPF (Load proportionality factor) curve from the process output, as shown in Figure 13; ordinary eggs The maximum value of the LPF curve of the shell is 4.270, so the bearing capacity of ordinary eggshells is 4.270MPa; as shown in Figure 14, the maximum value of the LPF curve of ribbed corrugated eggshells is 18.469, so the bearing capacity of ordinary eggshells is 18.469MPa;

The comparison results between the two are shown in Figure 15. The load-bearing capacity of the ribbed corrugated eggshell is about 4.3 times that of the ordinary eggshell, which further proves the superiority of the ribbed corrugated egg-shaped pressure-resistant shell and the reliability of this application.

The above are only preferred embodiments of the present invention. The protection scope of the present invention is not limited to the above-mentioned embodiments. All technical solutions that fall under the idea of the present invention belong to the protection scope of the present invention. It should be pointed out that for those of ordinary skill in the art, several improvements and modifications without departing from the principle of the present invention should be regarded as the protection scope of the present invention.

Claims

A ribbed corrugated egg-shaped pressure-resistant shell device, characterized by: including a small-end head plate (1) at the upper end and a large-end head plate (5) at the lower end;

A corrugated egg sheet body (4) is installed between the small end head plate (1) and the big end head plate (5). (5), several longitudinal ribs (2) are installed at equal intervals on the outside of the corrugated egg sheet body (4);

Ring ribs (3) for connecting the longitudinal ribs (2) are installed at the middle and lower ends of several of the longitudinal ribs (2).
A ribbed corrugated egg-shaped pressure-resistant shell device according to claim 1, characterized in that:

The number of longitudinal ribs (2) is at least 12.
A ribbed corrugated egg-shaped pressure-resistant shell device according to claim 1, characterized in that:

Several of the longitudinal ribs (2) are welded to the small end head plate (1) and the big end head plate (5).
A ribbed corrugated egg-shaped pressure-resistant shell device according to claim 1, characterized in that:

The small end head plate (1) and the large end head plate (5) both include a central end placed inside, and at least 12 extension ends are evenly distributed around the center end.
A method for processing a ribbed corrugated egg-shaped pressure-resistant shell device as described in any one of claims 1 to 4, characterized in that the specific operating steps are as follows:

Step 1. Determine the rib profile equation of longitudinal rib 2, in which the rib profile equation of longitudinal rib 2 is designed using the N-R equation;

Step 2. Design the ribbed corrugated egg-shaped pressure shell cross-section;

Step 3. Draw lines, cut and blank according to the shell expansion diagram;

Step 4. Bend the 12-piece shell;

Step 5. Determine the size of the longitudinal rib 2 according to the mechanical formula;

Step 6. Process the longitudinal rib 2 according to the longitudinal rib 2 drawing;

Step 7. Assemble and weld the 12-piece bent shells and the longitudinal ribs 2; weld a piece of bent shell on both sides of each longitudinal rib, and the 12-piece shells and 12 longitudinal ribs are alternately welded into a complete case;

Step 8. Assemble and weld the head plates at both ends; cut out the upper and lower head plates according to the outline of the schematic diagram, and then weld them to the complete welded shell;

Step 9: Process the ring rib 3 according to the ring rib 3 drawing;

Step 10. Assemble and weld the ring ribs 3 on the pressure shell; then weld the processed ring ribs 3 on the ribbed corrugated egg-shaped pressure shell one by one; the processing of the ribbed corrugated egg-shaped pressure shell is completed. .