CAE (Computer Aided Engineering)-assisted bathyscaphe pressure-resistant shell structure design and strength analysis method thereof

Abstract

The invention discloses a CAE (Computer Aided Engineering)-assisted structure design and strength analysis method for a pressure-resistant shell of a bathyscaphe, and relates to the technical field of pressure-resistant shells, which comprises the following steps of: designing the pressure-resistant shell structure by CAE software, carrying out analogue simulation, analyzing the stress distribution condition of the pressure-resistant shell, optimizing the pressure-resistant shell structure, and analyzing the strength of the pressure-resistant shell. Compared with the prior art, the pressure-resistant shell has the advantages that through the modular and reconfigurable design scheme, a module with a fault can be independently maintained or replaced in a relatively short time, function extension can be conveniently carried out on the pressure-resistant shell, a new module is integrated in an original pressure-resistant shell frame by reconfiguring the module, and the pressure-resistant shell is convenient to assemble and disassemble. Functions can be upgraded without redesigning and manufacturing the whole pressure-resistant shell, and the requirements for the structure and functions of the pressure-resistant shell are different for different deep sea tasks such as deep sea resource exploration, marine organism research and submarine topography surveying and mapping.

Description

Technical Field

[0001] The present invention relates to the technical field of pressure hulls, and in particular to a CAE-assisted deep-sea submersible pressure hull structure design and strength analysis method thereof. Background Art

[0002] Deep-sea submersibles are high-tech equipment that can operate, detect and research in deep-sea environments. They can withstand huge water pressure, carry various scientific instruments and equipment, and go deep into the seabed thousands or even tens of thousands of meters deep, providing an important means for humans to understand the ocean, develop marine resources, and explore the mysteries of the ocean. Deep-sea submersibles are mainly divided into manned submersibles, unmanned submersibles (including remotely operated vehicles ROV and autonomous submersibles AUV) and other types. They play an indispensable role in deep-sea exploration, marine scientific research, seabed resource development, deep-sea rescue and other fields;

[0003] With the continuous development of deep-sea exploration and resource development technology, deep-sea submersibles are playing an increasingly important role in the fields of marine scientific investigation and underwater engineering operations. As a key component of deep-sea submersibles, the structural design and strength analysis of the pressure hull are directly related to the safety and reliability of the submersible.

[0004] The deep-sea environment is complex and changeable. The pressure hull needs to withstand huge water pressure and complex mechanical environment, which puts extremely high demands on the design and strength analysis of the pressure hull. To this end, we propose a CAE-assisted deep-sea submersible pressure hull structure design and its strength analysis method. Summary of the invention

[0005] The object of the present invention is to provide a CAE-assisted deep-sea submersible pressure hull structure design and strength analysis method thereof.

[0006] In order to solve the problems raised in the above background technology, the present invention provides the following technical solutions: A CAE-assisted deep-sea submersible pressure hull structure design, including using CAE software to design the pressure hull structure, and performing simulation, analyzing the stress distribution of the pressure hull, and optimizing the pressure hull structure, characterized in that the specific operation steps of using CAE to design the pressure hull structure are as follows:

[0007] Step 1: Use modular and reconfigurable design to construct the pressure hull and conduct preliminary design of the structure of the submersible pressure hull;

[0008] Step 2: Perform simulation using CAE software to analyze the stress distribution and deformation of the pressure hull under different pressures;

[0009] Step 3: Optimize the pressure hull using an adaptive structure according to the stress distribution and deformation inside the pressure hull;

[0010] Step 4: Assemble the module as a whole, consider the temperature and corrosion factors in the deep sea environment, and select and optimize the pressure hull material.

[0011] As a further solution of the present invention: In the step 1, according to the functional requirements of the submersible, the pressure hull is divided into different functional modules, including a manned cabin module, an equipment module, an energy cabin module and a propulsion cabin module. Each module is independent in structure. The shape of the manned cabin module is set to be spherical, and the shape of the equipment cabin module is set to be cylindrical. According to the working depth of the submersible, the thickness of the pressure hull is calculated using the formula:

[0012]

[0013] Wherein, t is the theoretical pressure hull thickness, ρ represents the density of the liquid, g represents the acceleration of gravity, h represents the diving depth of the deep-sea submersible, D represents the diameter of the pressure hull of the deep-sea submersible, [σ] represents the allowable stress of the pressure hull material of the deep-sea submersible, and the thickness of the pressure hull of the spherical manned cabin module is calculated according to the diving depth of the deep-sea submersible.

[0014] As a further solution of the present invention: in the step 2, the basic geometric shapes of each module are created in SolidWorks respectively. During the modeling process, the key dimensions of the module are set as parameter variables, including diameter, length and wall thickness, and a structure composed of annular stiffeners and longitudinal stiffeners is added inside the pressure hull. The pressure hull model is parameterized and imported into the optimization module of the CAE software, the pressure hull model is meshed, and local mesh refinement is performed in stress concentration areas, including the connection parts of the pressure hull, the edges of the openings, and the intersections between the internal reinforcement structure and the pressure hull. The number of meshes is increased to 2-3 times the number of continuous parts with uniform stress distribution, regular geometry and uniform pressure distribution in the pressure hull. According to the actual installation and constraints of the submersible pressure hull, corresponding boundary conditions are set in the CAE software, including strength constraints, stability constraints, geometric constraints and material property constraints. The pressure situation is analyzed, and a pressure load of an actual simulated depth is applied to the surface of the pressure hull. After completing the model setting, boundary conditions and load application, the solver of the CAE software is used to solve and calculate. After the calculation is completed, the stress distribution of the pressure hull is checked through the post-processing module of the CAE software.

[0015] As a further solution of the present invention: In the step 3, the structure of the pressure-resistant shell is optimized according to the stress distribution inside the pressure-resistant shell, titanium alloy is selected as the cylinder material of the magnetorheological fluid damper, an electromagnetic coil is arranged around the cylinder, the strength of the magnetic field is adjusted by changing the current intensity in the coil, and the viscosity and damping of the magnetorheological fluid are controlled. The electromagnetic coil is packaged with a polyimide film, and the number of turns and wire diameter of the coil are designed according to the required magnetic field strength requirements. The calculation formula is:

[0016]

[0017] Among them, let I 计 is the current represented by different numbers of turns, B represents the magnetic field strength, the value range of B is 0.5T-1T, μ represents the absolute magnetic permeability, L represents the magnetic path length, N s Represents the actual number of coil turns, N s The value range is 100-500 turns. After obtaining the current corresponding to the actual number of coil turns, use the calculation formula:

[0018]

[0019] Where d represents the coil wire diameter, ρ represents the wire resistivity, D represents the coil diameter, and V represents the power supply voltage. The wire diameter and current corresponding to the actual number of coil turns are calculated. The coil generates a stable magnetic field under the working voltage. n magnetorheological fluid dampers are arranged at the connection position and opening edge of the pressure-resistant shell. The angle between two adjacent magnetorheological fluid dampers is The value range of n is 4-6. Vibration sensors and pressure sensors are installed on the top, bottom, sides of the pressure hull and the joints between modules, and the vibration sensors, pressure sensors and magnetorheological fluid dampers are connected to the main control system. During the dive of the submersible, the water pressure changes with the increase of depth. According to the vibration and pressure signals detected by the sensor, the main control system adjusts the electromagnetic coil current in real time to make the magnetorheological fluid damper generate corresponding damping force, thereby absorbing and consuming vibration energy.

[0020] As a further solution of the present invention: in the step four, the connection interfaces of each module are designed in a standardized manner, and the size, shape, connection method and electrical and hydraulic interfaces of the interfaces are uniformly specified. The electrical interfaces of all modules use waterproof plugs and sockets of the same specifications, the hydraulic interfaces use the same pipe diameter and connecting threads, the control system adopts modular programming and interface design, the control unit of each module is convenient for communication and data exchange with the main control system, the connection ports between modules are connected by standardized flanges, the flange connection surfaces between modules are sealed with rubber sealing rings, the main sealing structure of the manned cabin is sealed with metal sealing rings, and titanium alloy is selected as the material of the pressure-resistant shell of each module.

[0021] As a further scheme of the present invention: in the step four, a heating fluid circulation system is installed inside the titanium alloy pressure-resistant shell, including a heating furnace, a circulation pump, a pipeline, a heat exchanger and an intelligent control system. Temperature sensors are installed on the surface of the pressure shell in a grid manner, and temperature change data around the pressure shell is collected at a frequency of 1Hz-10Hz. After receiving the temperature data, the intelligent control system automatically adjusts the parameters of the intelligent control system according to the received temperature data, controls the heating furnace to heat the fluid to a set temperature, and the circulation pump transports the hot fluid through a pipeline to the heat exchanger around the pressure shell, transfers the heat to the pressure shell by heat conduction, and then the hot fluid returns to the heating furnace for circulation heating. During the operation of the heating fluid circulation system, the temperature change of the pressure shell is continuously monitored, and the parameters of the intelligent control system are adjusted and optimized.

[0022] In addition, the present invention also provides a CAE-assisted deep-sea submersible pressure hull strength analysis method, and the specific operation steps of the CAE-assisted deep-sea submersible pressure hull strength analysis method are as follows:

[0023] Step 1: Use CAE software to establish a finite element model of the deep-sea diving pressure hull and perform strength analysis on the model;

[0024] Step 2: Combined with experimental data verification, the simulation results are checked and corrected to ensure the accuracy and reliability of the strength analysis, and the pressure hull structure is optimized based on the strength analysis results;

[0025] Step 3: After completing the structural design and strength analysis, conduct a comprehensive evaluation of the overall performance of the pressure hull.

[0026] As a further scheme of the present invention: in the step one, in the deep sea environment, the pressure hull is subjected to pressure and impact of ocean currents at the same time, the fluid domain and the solid domain are coupled to model, and in the fluid domain, the ocean current velocity and pressure are set, and for the solid domain, the macroscopic mechanical properties of the pressure hull depend on the microscopic crystal structure and grain characteristics, and in the CAE software analysis, the crystal plasticity theory is used to construct a microscopic structural model, and the titanium alloy is regarded as an aggregate composed of grains, each grain having a specific crystal orientation, shape and size, and the grain boundary characteristics between the titanium alloy grains are defined, including the strength and slip resistance of the grain boundaries, and a crystal plasticity model is established, considering the slip behavior of the slip system when subjected to force, and the coordinated deformation mechanism between the grains, and the crystal plasticity model is divided into finite element units through the finite element module in the CAE software, and the deformation and stress distribution of the entire model under given loads and boundary conditions are solved by integrating the stress-strain relationship of each unit, and in the macroscopic structural analysis process, the mechanical response in the microscopic structural model is mapped to the macroscopic structural model to achieve micro-macro bidirectional coupling strength analysis.

[0027] As a further solution of the present invention: in the step 2, the simulation results are compared with the test data, the test data include the stress distribution, deformation and failure mode of the pressure hull, and there is a deviation between the simulation results and the theoretical data in the result verification. The material parameters of the model, the geometric parameters of the model and the boundary conditions are adjusted, and the simulation analysis is re-performed. When stress concentration and deformation occur in the simulation results, the model structure is optimized, and the optimized model is re-simulated and analyzed. The model needs to be verified and corrected in a cycle, and the model parameters and structure are adjusted in each cycle according to the comparison between the most recently refreshed simulation results and the experimental data.

[0028] As a further scheme of the present invention: In the step three, the safety of the pressure hull is evaluated, the stress of the pressure hull under the design pressure is calculated and compared with the allowable stress of the material, the temperature changes in the deep sea environment and the additional loads of ocean current impact are considered, the stress results are obtained through fluid-solid coupling analysis, the relationship between the total stress and the allowable stress is checked, the influence of geometric defects occurring during the manufacturing and use of the pressure hull on the stability is analyzed, the simulation analysis is carried out by introducing the defect model, the stress changes and deformation of the defective parts are observed, and the degree of weakening of the overall stability is evaluated, the sealing structure design of the pressure hull is evaluated, the service life of the sealing structure is evaluated through durability tests, the performance changes of the sealing structure after use are considered, and maintenance and replacement cycles are formulated to ensure that the sealing performance of the sealing structure meets the requirements during the entire service life of the submersible.

[0029] By adopting the above technical solution, compared with the prior art, the beneficial effects of the present invention are:

[0030] 1. The present invention can repair or replace the faulty module separately in a relatively short time through modular and reconfigurable design, and conveniently expand the function of the pressure hull. By reconfiguring the module and integrating the new module into the original pressure hull framework, the function upgrade can be achieved without redesigning and manufacturing the entire pressure hull. Different deep-sea tasks, such as deep-sea resource exploration, marine biological research, seabed topography mapping, etc., have different requirements for the structure and function of the pressure hull. The reconfigurable modular design can make the pressure hull quickly adjusted according to the specific task, and can make the pressure hull well adapt to various task scenarios. The modular design can make the various modules of the pressure hull be manufactured simultaneously on different production lines or factories, which greatly improves the manufacturing efficiency. Moreover, each module can be independently quality controlled and tested to ensure that the quality of each module meets the design requirements.

[0031] 2. The modules of the present invention use standardized connection interfaces, which makes the assembly process simpler and more efficient. Compared with the complex assembly process of the integral structure, modular assembly can reduce assembly errors and improve assembly accuracy. During the assembly process, the staff quickly completes the connection and fixation of the modules according to the standard operating procedures, which reduces the assembly time and difficulty. During the module manufacturing process, the materials and manufacturing processes are reasonably selected according to the functions and importance of the modules to avoid excessive design and waste. For non-critical auxiliary modules, relatively low-cost materials and simple manufacturing processes are used, while for core modules that withstand high pressure, high-performance materials and precision manufacturing processes are used to reduce material and manufacturing costs while ensuring the overall performance of the pressure-resistant shell. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic diagram of the CAE-assisted deep-sea submersible pressure hull structure design process in an embodiment of the present invention:

[0033] Figure 2 It is a schematic diagram of the process of CAE-assisted deep-sea submersible pressure hull strength analysis method in an embodiment of the present invention. DETAILED DESCRIPTION

[0034] The specific embodiments of the present invention are further described below in conjunction with the accompanying drawings. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0035] The present invention provides a CAE-assisted deep-sea submersible pressure hull structure design, including using CAE software to design the pressure hull structure, and performing simulation, analyzing the stress distribution of the pressure hull, and optimizing the pressure hull structure. The specific operation steps of using CAE to design the pressure hull structure are as follows:

[0036] Step 1: Use modular and reconfigurable design to construct the pressure hull and conduct preliminary design of the structure of the submersible pressure hull;

[0037] Step 2: Perform simulation using CAE software to analyze the stress distribution and deformation of the pressure hull under different pressures;

[0038] Step 3: Optimize the pressure hull using an adaptive structure according to the stress distribution and deformation inside the pressure hull;

[0039] Step 4: Assemble the module as a whole, consider the temperature and corrosion factors in the deep sea environment, and select and optimize the pressure hull material.

[0040] In one embodiment of the present invention: in the step 1, according to the functional requirements of the submersible, the pressure hull is divided into different functional modules, including a manned cabin module, an equipment module, an energy cabin module and a propulsion cabin module, each module is structurally independent, the shape of the manned cabin module is set to be spherical, and the shape of the equipment cabin module is set to be cylindrical. According to the working depth of the submersible, the thickness of the pressure hull is calculated using the formula:

[0041]

[0042] Wherein, t is the theoretical pressure hull thickness, ρ represents the density of the liquid, g represents the acceleration of gravity, h represents the diving depth of the deep-sea submersible, D represents the diameter of the pressure hull of the deep-sea submersible, [σ] represents the allowable stress of the pressure hull material of the deep-sea submersible, and the thickness of the pressure hull of the spherical manned cabin module is calculated according to the diving depth of the deep-sea submersible.

[0043] In one embodiment of the present invention: in the step 2, the basic geometric shapes of each module are created in SolidWorks respectively. During the modeling process, the key dimensions of the module are set as parameter variables, including diameter, length and wall thickness, and a structure composed of annular stiffeners and longitudinal stiffeners is added inside the pressure hull. The pressure hull model is parameterized and imported into the optimization module of the CAE software, the pressure hull model is meshed, and local mesh refinement is performed in stress concentration areas, including the connection parts of the pressure hull, the edges of the openings, and the junctions between the internal reinforcement structure and the pressure hull. The number of meshes is increased to 2-3 times the number of continuous parts with uniform stress distribution, regular geometry and uniform pressure distribution in the pressure hull. According to the actual installation and constraints of the submersible pressure hull, corresponding boundary conditions are set in the CAE software, including strength constraints, stability constraints, geometric constraints and material property constraints. The pressure situation is analyzed, and a pressure load of an actual simulated depth is applied to the surface of the pressure hull. After completing the model setting, boundary conditions and load application, the solver of the CAE software is used to solve and calculate. After the calculation is completed, the stress distribution of the pressure hull is checked through the post-processing module of the CAE software.

[0044] In one embodiment of the present invention: in the step 3, the structure of the pressure-resistant shell is optimized according to the stress distribution inside the pressure-resistant shell, titanium alloy is selected as the cylinder material of the magnetorheological fluid damper, an electromagnetic coil is arranged around the cylinder, the strength of the magnetic field is adjusted by changing the current intensity in the coil, and the viscosity and damping of the magnetorheological fluid are controlled. The electromagnetic coil is packaged with a polyimide film, and the number of turns and wire diameter of the coil are designed according to the required magnetic field strength requirements. The calculation formula is:

[0045]

[0046] Among them, let I计 is the current represented by different numbers of turns, B represents the magnetic field strength, the value range of B is 0.5T-1T, μ represents the absolute magnetic permeability, L represents the magnetic path length, N s Represents the actual number of coil turns, N s The value range is 100-500 turns. After obtaining the current corresponding to the actual number of coil turns, use the calculation formula:

[0047]

[0048] Where d represents the coil wire diameter, ρ represents the wire resistivity, D represents the coil diameter, and V represents the power supply voltage. The wire diameter and current corresponding to the actual number of coil turns are calculated. The coil generates a stable magnetic field under the working voltage. n magnetorheological fluid dampers are arranged at the connection position and opening edge of the pressure-resistant shell. The angle between two adjacent magnetorheological fluid dampers is The value range of n is 4-6. Vibration sensors and pressure sensors are installed on the top, bottom, sides of the pressure hull and the joints between modules, and the vibration sensors, pressure sensors and magnetorheological fluid dampers are connected to the main control system. During the dive of the submersible, the water pressure changes with the increase of depth. According to the vibration and pressure signals detected by the sensor, the main control system adjusts the electromagnetic coil current in real time to make the magnetorheological fluid damper generate corresponding damping force, thereby absorbing and consuming vibration energy.

[0049] In one embodiment of the present invention: in the step four, the connection interface of each module adopts a standardized design, and the size, shape, connection method and electrical and hydraulic interfaces of the interface are uniformly specified. The electrical interfaces of all modules adopt waterproof plugs and sockets of the same specifications, the hydraulic interfaces adopt the same pipe diameter and connecting threads, the control system adopts modular programming and interface design, the control unit of each module is convenient for communication and data exchange with the main control system, the connection ports between modules are connected by standardized flanges, the flange connection surfaces between modules are sealed with rubber sealing rings, the main sealing structure of the manned cabin is sealed with metal sealing rings, and titanium alloy is selected as the material of the pressure-resistant shell of each module.

[0050] In one embodiment of the present invention: in the step four, a heating fluid circulation system is installed inside the titanium alloy pressure-resistant shell, including a heating furnace, a circulation pump, a pipeline, a heat exchanger and an intelligent control system. Temperature sensors are installed on the surface of the pressure shell in a grid-like manner, and temperature change data around the pressure shell is collected at a frequency of 1Hz-10Hz. After receiving the temperature data, the intelligent control system automatically adjusts the parameters of the intelligent control system according to the received temperature data, controls the heating furnace to heat the fluid to a set temperature, and the circulation pump transports the hot fluid through a pipeline to the heat exchanger around the pressure shell, transfers the heat to the pressure shell by heat conduction, and then the hot fluid returns to the heating furnace for circulation heating. During the operation of the heating fluid circulation system, the temperature change of the pressure shell is continuously monitored, and the parameters of the intelligent control system are adjusted and optimized.

[0051] In addition, the present invention also provides a CAE-assisted deep-sea submersible pressure hull strength analysis method for CAE-assisted deep-sea submersible pressure hull structure design. The specific operation steps of the CAE-assisted deep-sea submersible pressure hull strength analysis method are as follows:

[0052] Step 1: Use CAE software to establish a finite element model of the deep-sea diving pressure hull and perform strength analysis on the model;

[0053] Step 2: Combined with experimental data verification, the simulation results are checked and corrected to ensure the accuracy and reliability of the strength analysis, and the pressure hull structure is optimized based on the strength analysis results;

[0054] Step 3: After completing the structural design and strength analysis, conduct a comprehensive evaluation of the overall performance of the pressure hull.

[0055] In one embodiment of the present invention: in the step one, in a deep-sea environment, the pressure hull is subjected to pressure and impact of ocean currents at the same time, the fluid domain and the solid domain are coupled to model, and in the fluid domain, the ocean current velocity and pressure are set. For the solid domain, the macroscopic mechanical properties of the pressure hull depend on the microscopic crystal structure and grain characteristics. In the CAE software analysis, the crystal plasticity theory is used to construct a microscopic structural model, and the titanium alloy is regarded as an aggregate composed of grains, each of which has a specific crystal orientation, shape and size. The grain boundary characteristics between the titanium alloy grains are defined, including the strength and slip resistance of the grain boundaries, and a crystal plasticity model is established, considering the slip behavior of the slip system when subjected to force, and the coordinated deformation mechanism between the grains. The crystal plasticity model is divided into finite element units through the finite element module in the CAE software, and the deformation and stress distribution of the entire model under given loads and boundary conditions are solved by integrating the stress-strain relationship of each unit. In the macroscopic structural analysis process, the mechanical response in the microscopic structural model is mapped to the macroscopic structural model to achieve micro-macro bidirectional coupling strength analysis.

[0056] In one embodiment of the present invention: in the step 2, the simulation results are compared with the test data, the test data includes the stress distribution, deformation and failure mode of the pressure hull, and there is a deviation between the simulation results and the theoretical data in the result verification. The material parameters of the model, the geometric parameters of the model and the boundary conditions are adjusted, and the simulation analysis is re-performed. When stress concentration and deformation occur in the simulation results, the model structure is optimized, and the optimized model is re-simulated and analyzed. The model needs to be verified and corrected in a cycle, and the model parameters and structure are adjusted in each cycle according to the comparison between the most recently refreshed simulation results and the experimental data.

[0057] In one embodiment of the present invention: In the step three, the safety of the pressure hull is evaluated, the stress of the pressure hull under the design pressure is calculated and compared with the allowable stress of the material, the temperature changes in the deep sea environment and the additional loads of the current impact are considered, the stress results are obtained through fluid-solid coupling analysis, the relationship between the total stress and the allowable stress is checked, the influence of geometric defects occurring during the manufacturing and use of the pressure hull on the stability is analyzed, the simulation analysis is carried out by introducing the defect model, the stress changes and deformation of the defective parts are observed, and the degree of weakening of the overall stability is evaluated, the sealing structure design of the pressure hull is evaluated, the service life of the sealing structure is evaluated through durability tests, the performance changes of the sealing structure after use are considered, and maintenance and replacement cycles are formulated to ensure that the sealing performance of the sealing structure meets the requirements during the entire service life of the submersible.

[0058] Example 1: As the depth increases, the pressure on the seawater increases, which leads to an increase in density. In the shallow sea area of ​​0m-200m, the density of seawater is 1020kg / m 3 -1025kg / m 3 In the shallow sea area of ​​200m-1000m, the seawater density is 1025kg / m 3 -1028kg / m 3 In the shallow sea area between 1000m and 6000m, the seawater density is 1028kg / m 3 -1040kg / m 3 The maximum operating depth of the deep-sea submersible is h = 4000m, and the seawater density used is ρ = 1030kg / m 3 For calculation, the diameter of the pressure hull of the deep-sea submersible is set to 5m. The pressure hull material of the deep-sea submersible is titanium alloy. The yield strength of titanium alloy is 900MPa, and the allowable stress [σ] is 70% of the yield strength, [σ] = 630MPa. The theoretical pressure hull thickness is calculated according to the formula:

[0059]

[0060] According to the above formula, it is calculated that the thickness of the pressure hull of the deep-sea submersible is 0.08m at the maximum diving depth, which provides an initial reference for the subsequent precise design. The temperature of the deep sea is as low as 1℃-4℃, and the salinity is in the range of 32‰-37‰. Low temperature and corrosion will lead to a reduction in the bearing capacity of the pressure hull. Titanium alloy is selected as the material of the pressure hull. The dense and protective oxide film formed on the surface of the titanium alloy prevents seawater from corroding the base material.

[0061] Embodiment 2: In a laboratory environment, a high-pressure test device is used to simulate a deep-sea pressure environment to perform a pressure test on the sealing structure. The pressure-resistant shell with the sealing structure is placed in the test device, and the pressure is gradually increased to the designed deep-sea pressure value, or even pressurized to 1.5-2 times the designed pressure. The gas leak detection method is used to detect the leakage. The pressure-resistant shell with the sealing structure is connected to the test interface of the helium mass spectrometer leak detection system to ensure that the connection parts are well sealed. The vacuum system of the helium mass spectrometer leak detector creates a low-pressure environment, and helium is introduced into the pressure-resistant shell. The helium will diffuse to the other side under the action of the pressure difference. By monitoring the helium signal intensity detected by the mass spectrometer, the leakage rate of the manned cabin sealing structure is required to be less than 10 -9 Pa·m 3 / s, if the detected leakage rate is lower than the qualified standard, the sealing structure is considered qualified. If the sealing is unqualified, the sealing structure needs to be inspected and repaired.

[0062] Embodiment 3: During the operation of the heating fluid circulation system, the temperature change of the pressure shell is continuously monitored. The temperature data fed back in real time by the temperature sensor is used to observe whether the temperature changes towards the target temperature range and whether it is within the allowable deviation range. If the temperature change does not meet expectations, the power of the heating furnace is adjusted according to the calculated control quantity. At the same time, the flow rate of the circulation pump is controlled to adjust the circulation speed of the hot fluid in the pipeline. The adjustment of the flow rate of the circulation pump and the adjustment of the power of the heating furnace are coordinated with each other. When rapid heating is required, while increasing the power of the heating furnace, the flow rate of the circulation pump is increased so that the hot fluid can transfer heat to the surrounding of the pressure shell more quickly. When the temperature is close to the target temperature, the flow rate of the circulation pump is reduced to reduce the speed of heat transfer and avoid temperature overshoot.

[0063] As attached Figure 1 As shown, CAE simulation is used to design the pressure hull, and the stress distribution and deformation of the pressure hull under different pressures are analyzed. The pressure hull structure is adaptively optimized according to the simulation results, and the pressure hull material is optimized according to the deep-sea environment to block the impact of the deep-sea low temperature environment on the internal temperature of the manned cabin and reduce the generation of thermal stress.

[0064] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions and variations of these embodiments are made without departing from the principles and spirit of the present invention, and still fall within the scope of protection of the present invention.

[0065] In the description of the specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0066] The above contents are merely examples and explanations of the present invention. Various modifications or additions to the specific embodiments described or replacements in similar ways by technicians in the technical field shall fall within the protection scope of the present invention as long as they do not deviate from the invention or exceed the scope defined by the claims.

[0067] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A CAE-assisted deep-sea submersible pressure hull structure design, including using CAE software to design the pressure hull structure, and performing simulation, analyzing the stress distribution of the pressure hull, and optimizing the pressure hull structure, characterized in that: The specific operation steps of using CAE to design the pressure hull structure are as follows: Step 1: Use modular and reconfigurable design to construct the pressure hull and conduct preliminary design of the structure of the submersible pressure hull; Step 2: Perform simulation using CAE software to analyze the stress distribution and deformation of the pressure hull under different pressures; Step 3: Optimize the pressure hull using an adaptive structure according to the stress distribution and deformation inside the pressure hull; Step 4: Assemble the module as a whole, consider the temperature and corrosion factors in the deep sea environment, and select and optimize the pressure hull material.

2. The CAE-assisted deep-sea submersible pressure hull structure design according to claim 1, characterized in that: In the step 1, according to the functional requirements of the submersible, the pressure hull is divided into different functional modules, including a manned cabin module, an equipment module, an energy cabin module and a propulsion cabin module. Each module is structurally independent. The shape of the manned cabin module is set to be spherical, and the shape of the equipment cabin module is set to be cylindrical. According to the working depth of the submersible, the thickness of the pressure hull is calculated using the formula: Wherein, t is the theoretical pressure hull thickness, ρ represents the density of the liquid, g represents the acceleration of gravity, h represents the diving depth of the deep-sea submersible, D represents the diameter of the pressure hull of the deep-sea submersible, [σ] represents the allowable stress of the pressure hull material of the deep-sea submersible, and the thickness of the pressure hull of the spherical manned cabin module is calculated according to the diving depth of the deep-sea submersible.

3. The CAE-assisted deep-sea submersible pressure hull structure design according to claim 2, characterized in that: In the step 2, the basic geometric shapes of each module are created in SolidWorks respectively. During the modeling process, the key dimensions of the module are set as parameter variables, including diameter, length and wall thickness, and a structure composed of annular stiffeners and longitudinal stiffeners is added inside the pressure hull. The pressure hull model is parameterized and imported into the optimization module of the CAE software, the pressure hull model is meshed, and local mesh refinement is performed in stress concentration areas, including the connection parts of the pressure hull, the edges of the openings, and the intersections between the internal reinforcement structure and the pressure hull. The number of meshes is increased to 2-3 times the number of continuous parts with uniform stress distribution, regular geometry and uniform pressure distribution in the pressure hull. According to the actual installation and constraints of the submersible pressure hull, corresponding boundary conditions are set in the CAE software, including strength constraints, stability constraints, geometric constraints and material property constraints. The pressure situation is analyzed, and a pressure load of an actual simulated depth is applied to the surface of the pressure hull. After completing the model setting, boundary conditions and load application, the solver of the CAE software is used to solve and calculate. After the calculation is completed, the stress distribution of the pressure hull is checked through the post-processing module of the CAE software.

4. The CAE-assisted deep-sea submersible pressure hull structure design according to claim 3, characterized in that: In the step 3, the structure of the pressure-resistant shell is optimized according to the stress distribution inside the shell, titanium alloy is selected as the cylinder material of the magnetorheological fluid damper, an electromagnetic coil is arranged around the cylinder, the strength of the magnetic field is adjusted by changing the current intensity in the coil, and the viscosity and damping of the magnetorheological fluid are controlled. The electromagnetic coil is packaged with a polyimide film, and the number of turns and wire diameter of the coil are designed according to the required magnetic field strength requirements. The calculation formula is: Among them, let I 计 is the current represented by different numbers of turns, R represents the magnetic field strength, the value range of x is 0.5T-1T, μ represents the absolute magnetic permeability, L represents the magnetic path length, N s Represents the actual number of coil turns, N s The value range is 100-500 turns. After obtaining the current corresponding to the actual number of coil turns, use the calculation formula: Where d represents the coil wire diameter, ρ represents the wire resistivity, D represents the coil diameter, and V represents the power supply voltage. The wire diameter and current corresponding to the actual number of coil turns are calculated. The coil generates a stable magnetic field under the working voltage. n magnetorheological fluid dampers are arranged at the connection position and opening edge of the pressure-resistant shell. The angle between two adjacent magnetorheological fluid dampers is The value range of n is 4-6. Vibration sensors and pressure sensors are installed on the top, bottom, sides of the pressure hull and the joints between modules, and the vibration sensors, pressure sensors and magnetorheological fluid dampers are connected to the main control system. During the dive of the submersible, the water pressure changes with the increase of depth. According to the vibration and pressure signals detected by the sensor, the main control system adjusts the electromagnetic coil current in real time to make the magnetorheological fluid damper generate corresponding damping force, thereby absorbing and consuming vibration energy.

5. The CAE-assisted deep-sea submersible pressure hull structure design according to claim 2, characterized in that: In the step four, the connection interfaces of each module are designed in a standardized manner, and the size, shape, connection method and electrical and hydraulic interfaces of the interfaces are uniformly specified. The electrical interfaces of all modules use waterproof plugs and sockets of the same specifications, the hydraulic interfaces use the same pipe diameter and connecting threads, the control system adopts modular programming and interface design, the control unit of each module is convenient for communication and data exchange with the main control system, the connection ports between modules are connected by standardized flanges, the flange connection surfaces between modules are sealed with rubber sealing rings, the main sealing structure of the manned cabin is sealed with metal sealing rings, and titanium alloy is selected as the material of the pressure-resistant shell of each module.

6. A CAE-assisted deep-sea submersible pressure hull strength analysis method according to claim 5, characterized in that: In the step 4, a heating fluid circulation system is installed inside the titanium alloy pressure-resistant shell, including a heating furnace, a circulation pump, a pipeline, a heat exchanger and an intelligent control system. Temperature sensors are installed on the surface of the pressure shell in a grid-like manner, and temperature change data around the pressure shell is collected at a frequency of 1 Hz-10 Hz. After receiving the temperature data, the intelligent control system automatically adjusts the parameters of the intelligent control system according to the received temperature data, controls the heating furnace to heat the fluid to a set temperature, and the circulation pump transports the hot fluid through a pipeline to the heat exchanger around the pressure shell, transfers the heat to the pressure shell by heat conduction, and then the hot fluid returns to the heating furnace for circulation heating. During the operation of the heating fluid circulation system, the temperature change of the pressure shell is continuously monitored, and the parameters of the intelligent control system are adjusted and optimized.

7. A CAE-assisted deep-sea submersible pressure hull strength analysis method applicable to the CAE-assisted deep-sea submersible pressure hull structure design according to any one of claims 1 to 6, characterized in that: The specific operation steps of the CAE-assisted deep-sea submersible pressure hull strength analysis method are as follows: Step 1: Use CAE software to establish a finite element model of the deep-sea diving pressure hull and perform strength analysis on the model; Step 2: Combined with experimental data verification, the simulation results are checked and corrected to ensure the accuracy and reliability of the strength analysis, and the pressure hull structure is optimized based on the strength analysis results; Step 3: After completing the structural design and strength analysis, conduct a comprehensive evaluation of the overall performance of the pressure hull.

8. A CAE-assisted deep-sea submersible pressure hull strength analysis method according to claim 7, characterized in that: In the step 1, in a deep-sea environment, the pressure hull is subjected to pressure and the impact of ocean currents at the same time, and the fluid domain and the solid domain are coupled to model. In the fluid domain, the ocean current velocity and pressure are set. For the solid domain, the macroscopic mechanical properties of the pressure hull depend on the microscopic crystal structure and grain characteristics. In the CAE software analysis, the crystal plasticity theory is used to construct a microscopic structural model, and the titanium alloy is regarded as an aggregate composed of grains, each of which has a specific crystal orientation, shape and size. The grain boundary characteristics between the titanium alloy grains are defined, including the strength and slip resistance of the grain boundaries, and a crystal plasticity model is established. The slip behavior of the slip system when subjected to force and the coordinated deformation mechanism between the grains are considered. The crystal plasticity model is divided into finite element units through the finite element module in the CAE software, and the deformation and stress distribution of the entire model under given loads and boundary conditions are solved by integrating the stress-strain relationship of each unit. In the macroscopic structural analysis process, the mechanical response in the microscopic structural model is mapped to the macroscopic structural model to achieve micro-macro bidirectional coupling strength analysis.

9. A CAE-assisted deep-sea submersible pressure hull strength analysis method according to claim 8, characterized in that: In the step 2, the simulation results are compared with the test data, the test data includes the stress distribution, deformation and failure mode of the pressure hull. In the result verification, there is a deviation between the simulation results and the theoretical data. The material parameters, geometric parameters and boundary conditions of the model are adjusted, and the simulation analysis is re-performed. When stress concentration and deformation occur in the simulation results, the model structure is optimized, and the optimized model is re-simulated and analyzed. The model needs to be verified and corrected in a cycle. Each cycle adjusts the model parameters and structure according to the comparison between the most recently refreshed simulation results and the experimental data.

10. A CAE-assisted deep-sea submersible pressure hull strength analysis method according to claim 8, characterized in that: In the step three, the safety of the pressure hull is evaluated, the stress of the pressure hull under the design pressure is calculated and compared with the allowable stress of the material, the temperature changes in the deep sea environment and the additional loads of the current impact are considered, the stress results are obtained through fluid-solid coupling analysis, the relationship between the total stress and the allowable stress is checked, the influence of geometric defects occurring during the manufacturing and use of the pressure hull on the stability is analyzed, the simulation analysis is carried out by introducing the defect model, the stress changes and deformation of the defective parts are observed, and the degree of weakening of the overall stability is evaluated, the sealing structure design of the pressure hull is evaluated, the service life of the sealing structure is evaluated through durability tests, the performance changes of the sealing structure after use are considered, and the maintenance and replacement cycles are formulated to ensure that the sealing performance of the sealing structure meets the requirements during the entire service life of the submersible.

Images