A method for designing a deep-sea pressure simulation device by mechanical pressurization

Abstract

The present invention relates to a method for designing a deep-sea pressure simulation device by mechanical pressurization, the method comprising the following steps: (S‑1) modeling: establishing a model of a deep-sea pressure simulation device in the simulation software ANSYS, the model comprising a pressure-resistant device, a support portion connected to the pressure-resistant device, and a base connected to the pressure-resistant device; (S‑2) gradual pressurization and topological optimization: on the model established in step (S‑1), applying simulated pressure to the pressure-resistant device through the support portion, and fixing and constraining the pressure-resistant device through the base; in the optimization process, applying simulated pressure to the pressure-resistant device, topologically optimizing the pressure-resistant device, then increasing the simulated pressure, topologically optimizing again, and so on until the simulated pressure is the design pressure, and topologically optimizing to obtain the deep-sea pressure simulation device. Compared with the prior art, the present invention has the advantages of quick and convenient design and high accuracy.

Description

Technical Field

[0001] The invention belongs to the field of design simulation for simulating deep sea pressure, and in particular relates to a method for designing a deep sea pressure simulation device through mechanical pressurization. Background Art

[0002] The ocean accounts for about 71% of the earth's surface area and contains extremely rich seabed resources, including oil, natural gas, various minerals, etc. Population and economic growth have brought about a continuous increase in demand for resources. Faced with the gradual depletion of land and coastal resources, the world will inevitably focus its future development on the deep sea, and development into the deep sea has become an inevitable trend.

[0003] In the key technology field of equipment development, my country's products still cannot meet the demand, and key supporting systems and equipment are basically monopolized by foreign countries. Therefore, it is particularly important to study and propose major special projects to ensure the construction of a strong maritime nation as soon as possible, vigorously promote the research and development of basic, forward-looking and key technologies in the marine field, and quickly improve and expand the ability to go deep and deep sea.

[0004] The development of marine resources is inseparable from various mechanical testing equipment. Today, as the diving depth has been repeatedly broken, humans have taken the exploration steps to the dark world of 7000m, or even deeper. With the continuous deepening of underwater operation research, humans have put forward higher requirements for the safety and reliability of deep-sea operation equipment. In the process of research and development of deep-sea operation equipment, an indispensable step is to undergo pressure tests with different indicators. For every 10m increase in seawater depth, the corresponding pressure will increase by about 0.1MPa. The marine environment is complex, and the deeper the seawater, the more difficult it is to test.

[0005] For hydraulic systems used in deepwater environments, the impact of water pressure on the system must be considered, otherwise the hydraulic system will not work properly. At present, the test method for seawater hydraulic components mostly uses all the components to be tested to be installed on the experimental device and sent to the predetermined ocean depth for testing. This test method is not only limited by many factors, such as power supply problems, test device weight, etc., but also has high costs and complex tests. Due to the many uncertain factors on the seabed, the safety of the test is also reduced, which seriously affects the accuracy of the real performance evaluation of seawater hydraulic components. For this reason, scientific and technological workers have also adopted various simulation methods. The traditional approach is to place the hydraulic control components and actuators in a pressure vessel that can withstand water pressure. This method will bring a series of problems such as bulky system, complex structure and special dynamic seals. Summary of the invention

[0006] The purpose of the present invention is to provide a method for designing a deep-sea pressure simulation device through mechanical pressurization in order to overcome the defects of the above-mentioned prior art, such as poor accuracy and complicated design process.

[0007] The purpose of the present invention can be achieved by the following technical solutions:

[0008] A method for designing a deep-sea pressure simulation device by mechanical pressurization, the method comprising the following steps:

[0009] (S-1) Modeling: Establishing a model of a deep-sea pressure simulation device in the simulation software ANSYS, the model including a pressure-resistant device, a support connected to the pressure-resistant device, and a base connected to the pressure-resistant device;

[0010] (S-2) Gradual pressurization and topology optimization: On the model established in step (S-1), simulated pressure is applied to the pressure-resistant device through the support part, and the pressure-resistant device is fixedly constrained by the base; during the optimization process, simulated pressure is applied to the pressure-resistant device, and topology optimization is performed on the pressure-resistant device, then the simulated pressure is increased, and topology optimization is performed again, and so on until the simulated pressure reaches the design pressure, and the deep-sea pressure simulation device is obtained by topology optimization.

[0011] Furthermore, in step (S-1), the pressure-resistant device includes a shell and an internal entity disposed in the shell.

[0012] Furthermore, the shell and the internal entity are both spherical, and the ratio of the diameter of the internal entity, the diameter of the internal cavity of the shell and the thickness of the shell is 250-270:210-230:15-25, preferably 260:220:20.

[0013] Furthermore, the support portion is a truncated cone structure and a large end of the truncated cone structure is fitted and connected to the surface of the pressure-resistant device.

[0014] Furthermore, the ratio of the large end diameter of the truncated cone structure to the outer diameter of the shell is 150-170:250-270, preferably 160:260; the ratio of the small end diameter, length and large end diameter of the truncated cone structure is 40-50:300-310:155-165, preferably 45:305:160.

[0015] Furthermore, the base is cylindrical, and the diameter of the base is equal to the diameter of the large end of the support part.

[0016] Furthermore, there are three support parts, namely the first support part, the second support part and the third support part; there are three bases, namely the first base, the second base and the third base; the second support part and the third support part are arranged opposite to each other, and the first support part is perpendicular to the second support part and the third support part; the first base is arranged opposite to the first support part, and the second base and the third base are arranged opposite to each other.

[0017] Furthermore, in step (S-2), the initial simulation pressure is designed to be 0.05 MPa, and after each topology optimization is completed, the simulation pressure is increased by 0.1 to 0.2 MPa, preferably 0.1 MPa.

[0018] Furthermore, each time the topology optimization is performed, the finite element analysis method is used to reduce the volume of the internal entity, and then the shape structure of the internal entity is optimized so that the overall stiffness of the pressure-resistant device is maximized, and the force difference at each point on the shell surface of the entire device body is ensured to be ≤0.01MPa, thereby ensuring that the force at each point on the shell surface of the entire device body is uniform.

[0019] The reduction value of the volume of the internal entity each time shall not exceed 50% of the entire volume of the internal entity.

[0020] Furthermore, the material of the deep sea pressure simulation device is titanium alloy.

[0021] The design principle of the present invention is:

[0022] The mature finite element analysis method is adopted, and the topology optimization technology in the software ANSYS is used to complete the optimization of the structure, wherein the topology optimization is shape optimization, and its purpose is to seek the highest utilization rate of the material so that the objective function (for example: overall stiffness, natural frequency) can obtain the maximum or minimum value. The present invention adopts the overall stiffness control method to ensure the maximum overall stiffness of the measured component and the uniformity of its stress.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] (1) The present invention adopts the simulation software ANSYS to avoid many unfavorable factors related to hydrostatic pressure in marine experiments, such as temperature, salinity, dissolved oxygen, pH value, redox potential, biofouling, calcium ion deposition and surface flow rate, making the experiment simpler and safer and reducing the cost of the experiment;

[0025] (2) The present invention uses a suitable deep-sea pressure simulation device to model. During the modeling process, the support uses a small diameter at the pressure end and a large diameter at the part in contact with the spherical surface, so that the pressure can be evenly transmitted. In addition, multiple supports and bases are used around the spherical surface to ensure the consistency of the pressure around the spherical surface after optimization. If only one support is used, it is found in the actual calculation process that no matter how it is optimized, it is difficult to ensure the uniformity of the pressure around the spherical surface.

[0026] (3) During the optimization process, the present invention first sets a constraint that the volume reduction does not exceed 50%, and at the same time sets the overall stiffness to the maximum value after the shape of the internal entity is optimized. If the topology optimization process does not set a constraint on the volume reduction, the volume may be excavated too much or too little. Excessive excavation leads to insufficient stiffness of the sphere after optimization, and too little excavation leads to insufficient space in the cavity. In addition, if the stiffness is not constrained to be maximum, it is difficult to ensure the uniformity of the surface pressure of the sphere after excavation. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the modeling structure of the present invention;

[0028] Figure 2 A cross-sectional view of the pressure-resistant device obtained by the present invention in the front direction;

[0029] Figure 3 A cross-sectional view of the pressure-resistant device obtained by the present invention in a top view;

[0030] Figure 4 A side sectional view of the pressure-resistant device obtained by the present invention;

[0031] Figure 5 is the overall equivalent stress distribution diagram of the model of the present invention;

[0032] Figure 6 It is an equivalent stress distribution diagram of the deep sea pressure simulation device of the present invention;

[0033] Figure 7 It is a quasi-static pressure distribution diagram of the cavity of the deep-sea pressure simulation device of the present invention;

[0034] Figure 8 A global pressure distribution diagram of the deep sea pressure simulation device of the present invention;

[0035] In the figure, 1 is a pressure-resistant device, 2 is a supporting part, 21 is a first supporting part, 22 is a second supporting part, 23 is a third supporting part, 3 is a base, 31 is a first base, 32 is a second base, 33 is a third base, 4 is a solid structure, 41 is a recessed structure, 42 is a supporting body, 421 is an upper bottom surface, 422 is a lower bottom surface, 423 is a side surface, 43 is a supporting branch, 44 is a first through hole, 45 is a second through hole, and 5 is a shell. DETAILED DESCRIPTION

[0036] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several variations and improvements may be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0037] Example

[0038] A method for designing a deep-sea pressure simulation device by mechanical pressurization, the method comprising the following steps:

[0039] (S-1) Modeling: Establish a model of the deep-sea pressure simulation device in the simulation software ANSYS, such as Figure 1 As shown, the model includes a pressure-resistant device 1, a support portion 2 connected to the pressure-resistant device 1, and a base 3 connected to the pressure-resistant device 1; wherein the pressure-resistant device 1 includes a shell 5 and an internal entity arranged in the shell 5, and when modeling, the shell 5 and the internal entity are both spherical; the support portion 2 is a truncated cone structure and the large end of the truncated cone structure is fitted and connected to the surface of the pressure-resistant device 1, the base 3 is cylindrical, and the diameter of the base 3 is equal to the diameter of the large end of the support portion 2; the structural size parameters of each component are shown in Table 1.

[0040] Table 1 Structural parameters

[0041]

[0042] like Figure 1 As shown, there are three support parts 2, namely the first support part 21, the second support part 22 and the third support part 23; there are three bases 3, namely the first base 31, the second base 32 and the third base; the second support part 22 and the third support part 23 are arranged opposite to each other, and the first support part 21 is perpendicular to the second support part 22 and the third support part 23; the first base 31 is arranged opposite to the first support part 21, and the second base 32 and the third base are arranged opposite to each other.

[0043] (S-2) Gradual pressurization and topology optimization: On the model established in step (S-1), simulated pressure is applied to the pressure-resistant device 1 through the support part 2, and the pressure-resistant device 1 is fixedly constrained through the base 3; during the optimization process, simulated pressure is applied to the pressure-resistant device 1, and the pressure-resistant device 1 is topologically optimized, and then the simulated pressure is increased, and the topology optimization is performed again, and so on until the simulated pressure reaches the design pressure, and the deep-sea pressure simulation device is obtained by topology optimization;

[0044] During the gradual pressurization process, the initial simulation pressure was designed to be 0.05 MPa. After each topology optimization was completed, the simulation pressure increased by 0.1 MPa.

[0045] During each topology optimization, the finite element analysis method is used to reduce the volume of the internal entity, and then the shape structure of the internal entity is optimized to maximize the overall stiffness of the pressure-resistant device 1, and to ensure that the force difference at each point on the surface of the shell 5 of the entire device body is ≤0.01MPa; the reduction value of the volume of the internal entity each time does not exceed 50% of the entire internal entity volume.

[0046] The schematic diagram of the deep-sea pressure simulation device finally optimized is shown in the figure below: Figure 2 , Figure 3 and Figure 4 As shown, the dark area in the figure is an internal solid structure 4 formed by the remaining material of the solid part. It can be seen from the figure that the volume of the internal solid part of the cavity is reduced by about 46% compared with the initial internal solid.

[0047] The optimized pressure-resistant device for deep-sea exploration is essentially a pressure vessel. The structural diagram of the deep-sea pressure-resistant device is shown in the figure. Figure 2 , Figure 3 and Figure 4 As shown, the optimized solid structure 4 inside the pressure-resistant device 1 includes a support body 42 fixedly connected to the inner wall of the shell on all sides and a support branch 43 connected to the support body 42. The outer side surface 423 of the support branch 43 is matched in shape and fixed to the inner wall of the shell. Two support branches 43 are provided, and the two support branches 43 are mirror-symmetrically connected to the two sides of the support body 42. The support body 42 is a columnar structure, which includes an upper bottom surface 421 and a lower bottom surface 422 parallel to each other, and a side surface 423 provided between the upper bottom surface 421 and the lower bottom surface 422. The structure is thick at both ends and thin in the middle. The edges of the upper bottom surface 421 and the lower bottom surface 422 are fixedly connected to the inner wall of the shell, and the middle side surface 423 is concave toward the center of the sphere to form a concave structure 41, which is not in contact with or fixed to the inner wall of the shell, that is, the entity between the side surface 423 and the shell is also dug out. The support body 42 is provided with a first through hole 44 in the X direction and a second through hole 45 in the Y direction. The axial direction of the columnar structure is the Z direction, and the X direction, the Y direction and the Z direction are perpendicular to each other. The cross section of the first through hole 44 is rectangular. The cross section of the second through hole 45 is rectangular. The distance between the upper bottom surface 421 and the lower bottom surface 422 is 0.3 times the diameter of the shell. The intersection of the central axis of the columnar structure and the shell is the vertex, and the support branch 43 extends toward the vertex. The support branch 43 is a thin shell structure with the inner side surface and the outer side surface parallel. Along the axial direction of the columnar structure, the height of the support branch 43 is 0.6 times the radius of the shell.

[0048] It can be seen from the figure that the volume of the solid part inside the cavity is reduced by about 46% compared with the initial internal solid part.

[0049] Further analysis of the overall and local stress distribution of the device shows that the overall equivalent stress distribution of the entire model is shown in Figure 5, where the shell equivalent stress distribution of the pressure-resistant device 1 is shown in Figure 5. Figure 6 As shown in the figure, it can be seen that the equivalent stress distribution on the shell surface is uniform. The stress in a few places is too large because of the Saint-Venant effect in the mechanical algorithm, which does not affect the accuracy of the result. The overall static pressure distribution of the shell is shown in Figure 7 As shown, Figure 8This is a global pressure distribution diagram. It can be seen that the pressure distribution around the cavity is uniform. Therefore, the optimized cavity structure can fully meet the requirements of the hydrostatic pressure environment of deep-sea testing and can be used for deep-sea pressure testing.

[0050] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art may make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A method for designing a deep-sea pressure simulation device by mechanical pressurization, characterized in that: The method comprises the following steps: (S-1) Modeling: Establishing a model of a deep-sea pressure simulation device in the simulation software ANSYS, the model comprising a pressure-resistant device (1), a support portion (2) connected to the pressure-resistant device (1), and a base (3) connected to the pressure-resistant device (1); (S-2) Gradual pressurization and topology optimization: On the model established in step (S-1), a simulated pressure is applied to the pressure-resistant device (1) through the support portion (2), and the pressure-resistant device (1) is fixedly constrained through the base (3); during the optimization process, a simulated pressure is applied to the pressure-resistant device (1), and the pressure-resistant device (1) is topologically optimized, and then the simulated pressure is increased, and the topology optimization is performed again, and so on until the simulated pressure reaches the design pressure, and the deep-sea pressure simulation device is obtained by topology optimization.

2. A method for designing a deep-sea pressure simulation device by mechanical pressurization according to claim 1, characterized in that: In step (S-1), the pressure-resistant device (1) comprises a shell and an internal entity arranged in the shell.

3. A method for designing a deep-sea pressure simulation device by mechanical pressurization according to claim 2, characterized in that: The shell and the internal entity are both spherical, and the ratio of the diameter of the internal entity, the diameter of the internal cavity of the shell and the thickness of the shell is 250-270:210-230:15-25.

4. A method for designing a deep-sea pressure simulation device by mechanical pressurization according to claim 2, characterized in that: The support portion (2) is a truncated cone-shaped structure, and the large end of the truncated cone-shaped structure is fitted and connected to the surface of the pressure-resistant device (1).

5. A method for designing a deep-sea pressure simulation device by mechanical pressurization according to claim 4, characterized in that: The ratio of the large end diameter of the truncated cone structure to the outer diameter of the shell is 150-170:250-270; the ratio of the small end diameter, length and large end diameter of the truncated cone structure is 40-50:300-310:155-165.

6. A method for designing a deep sea pressure simulation device by mechanical pressurization according to claim 4, characterized in that: The base (3) is cylindrical, and the diameter of the base (3) is equal to the diameter of the large end of the support part (2).

7. The method for designing a deep-sea pressure simulation device by mechanical pressurization according to claim 1, characterized in that: The support parts (2) are provided with three, namely a first support part (21), a second support part (22) and a third support part (23); the base (3) is provided with three, namely a first base (31), a second base (32) and a third base; the second support part (22) and the third support part (23) are arranged opposite to each other, and the first support part (21) is perpendicular to the second support part (22) and the third support part (23); the first base (31) is arranged opposite to the first support part (21), and the second base (32) and the third base are arranged opposite to each other.

8. The method for designing a deep-sea pressure simulation device by mechanical pressurization according to claim 1, characterized in that: In step (S-2), the initial simulation pressure is designed to be 0.05 MPa, and after each topology optimization is completed, the simulation pressure is increased by 0.1 to 0.2 MPa.

9. The method for designing a deep-sea pressure simulation device by mechanical pressurization according to claim 1, characterized in that: Each time the topology is optimized, the finite element analysis method is used to reduce the volume of the internal entity, and then the shape structure of the internal entity is optimized so that the overall stiffness of the pressure-resistant device (1) is maximized, and the force difference at each point on the shell surface of the entire device body is ensured to be ≤0.01MPa.

10. A method for designing a deep sea pressure simulation device by mechanical pressurization according to claim 9, characterized in that: The reduction value of the volume of the internal entity each time shall not exceed 50% of the entire volume of the internal entity.

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