Valve structure simulation method and device based on finite element analysis, and readable storage medium

Abstract

The application discloses a valve structure simulation method and device based on finite element analysis, and a readable storage medium, and belongs to the technical field of valves. The simulation method mainly comprises a multi-physical field coupling method: control equations of multiple physical fields are solved to obtain a control equation group, including a physical field parameter column array corresponding to the physical fields, the control equation group including fluid mechanics equations, heat and moisture conduction equations and elastic mechanics equations, forming a unified equation group, and then being discretized; the discretization converts continuous partial differential equations into algebraic equations; for transient problems, a display or implicit time integration scheme is used for time discretization of the simultaneous equations. The device comprises a memory, a processor and a computer program. The storage medium stores a terminal program for executing the above method. The application can simultaneously consider factors such as fluid flow, heat and moisture conduction and structural mechanics, and through integration of advanced methods and optimization strategies, improves simulation real-time performance, ensures work efficiency and improves precision.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of valves, and particularly relates to a valve structure simulation method and device based on finite element analysis and a readable storage medium. BACKGROUND

[0002] A valve is a control component in a fluid conveying system, and has functions of cutoff, regulation, flow guiding, anti-backflow, pressure stabilization, shunt or overflow pressure relief. The valve is a device for controlling the direction, pressure and flow of fluid in a fluid system, and is a device for stopping or controlling the flow of medium (liquid, gas, powder) in a pipe and equipment. The valve realizes functions of flow guiding, cutoff, throttling, check, shunt or overflow pressure relief by changing a passage section and a medium flow direction. An electric valve is a device for driving a valve to open or close or regulate by using an electric actuator. The electric valve converts electric energy into mechanical energy, and drives the valve to open or close by a motor, so as to realize control over fluid.

[0003] The valve field is developing towards intelligence, automation, high precision, high efficiency and the like. A servo valve belongs to a valve with high-precision control. The servo valve is a precise hydraulic or pneumatic control key element of a servo system, is used for accurately controlling the pressure and flow of fluid, has advantages of fast response, large output power, high control precision and the like, and its performance directly influences the reliability and safety of operation of the servo system, and has been widely applied to fields of petroleum, chemical industry, metallurgy, ship, aviation, spaceflight and the like. Since the working principle of the servo valve involves interaction of multiple physical fields (such as fluid mechanics, hygrothermal mechanics, structural mechanics and the like), multi-physical field simulation is crucial for optimizing the design and performance of the servo valve.

[0004] In the modern engineering design of servo valves, many systems need to consider the interaction between multiple physical phenomena such as fluid flow, heat and moisture conduction, structural mechanics, etc., and the traditional single physical field simulation cannot accurately capture these complex interactions, resulting in inaccurate or inefficient design results. Although there are multi-physical field coupling simulation methods in the prior art, the simplified assumption method currently used may lead to simulation results that do not match the actual situation, and there are comprehensive multi-physical field considerations, but often only fluid-structure coupling or thermal-structure coupling is considered, the inaccuracy of the simulation results leads to insufficient accuracy of the valve structure design, and the accuracy improvement is limited, especially in complex engineering applications such as aerospace, intelligent equipment, etc. which require high precision. In addition, the current valve structure design also has the following shortcomings: high computational cost, multi-physical field coupling usually requires a large amount of computing resources, which is difficult to meet through manual calculation or experimental testing; convergence difficulty, strong coupling between different physical fields may lead to numerical instability and increased difficulty in solving; low computational efficiency, a large number of simulation calculations are performed on the valve structure during design, but the design efficiency is limited. Therefore, developing a simulation method that can effectively handle multi-physical field coupling problems is crucial to improving design accuracy and efficiency. SUMMARY

[0005] The present application aims to at least partially solve the technical problem of inaccurate simulation results of valve structures, and for this purpose, the present application provides a valve structure simulation method and device based on finite element analysis, a readable storage medium, which can simultaneously consider factors such as fluid flow, heat and moisture conduction, and structural mechanics that affect valve structures, simulate by establishing a multi-physical field coupling relationship, integrate advanced methods and optimization strategies, improve the real-time performance of multi-physical field coupling simulation, and ensure work efficiency while improving accuracy.

[0006] In a first aspect, the embodiments of the present application provide a valve structure simulation method based on finite element analysis, which includes:

[0007] designing a geometric model according to the structural parameters of the valve structure, and dividing the geometric model into multiple components;

[0008] defining material parameters for each component and associating the material parameters with each component;

[0009] using a finite element simulation model software to divide the geometric model into a grid, forming a grid element, and taking all grid elements as simulation analysis objects;

[0010] establishing a coupling model of the influence of fluid flow, humidity transmission, heat transfer, and mechanical deformation on the valve structure; setting boundary conditions and initial conditions;

[0011] importing the coupling model into the simulation model software and performing multi-physical field coupling simulation analysis;

[0012] According to the simulation result, a grid element with a failure risk in the geometric model is identified, and the design is optimized.

[0013] In some embodiments, the coupling model comprises:

[0014] a continuity equation of the fluid for describing a motion state of the fluid flow;

[0015] a heat conduction equation for describing temperature changes of the components themselves caused by environmental heat sources and self Joule heat production;

[0016] a moisture diffusion equation for describing moisture changes of the components themselves caused by environmental humidity and self moisture diffusion;

[0017] a dynamics equation for describing displacement, velocity, acceleration and stress changes of the components of the valve structure themselves.

[0018] In some embodiments, the dynamics equation is described based on a multi-degree-of-freedom system as a relationship among a displacement vector, a velocity vector, an acceleration vector and an external force vector, wherein coefficients of the displacement vector, the velocity vector and the acceleration vector are a mass matrix, a damping matrix and a stiffness matrix, respectively.

[0019] In some embodiments, when performing the simulation analysis of the multi-physical field coupling, the equations corresponding to the coupling model are solved to obtain simulation results of temperature distribution, humidity distribution, stress distribution and displacement distribution.

[0020] In some embodiments, when solving the equations corresponding to the coupling model:

[0021] energy conservation equations, mass conservation equations, momentum conservation equations and coupling mechanisms of the multi-physical field coupling are introduced;

[0022] the continuous multi-physical field is discretized into a finite number of physical field units corresponding to the grid elements;

[0023] the discretized algebraic equation system of each physical field unit is solved to obtain an approximate solution.

[0024] In some embodiments, introducing the coupling mechanism comprises: establishing a relationship formula of temperature, humidity and stress through a balance equation, a displacement equation and a thermal stress-strain equation; establishing a relationship formula of temperature-induced stress changes and humidity-induced stress changes through thermal stress and moisture stress; establishing a relationship formula of introducing phase change effects by adding a latent heat of vaporization term; and establishing a relationship formula of fluid pressure, density and flow rate through a continuity equation and a mass conservation equation.

[0025] In some embodiments, solving the discretized algebraic equation system specifically comprises:

[0026] The partial differential equations of the energy conservation equation, the mass conservation equation and the momentum conservation equation are converted into integral forms by introducing test functions, to form expressions of weak forms respectively;

[0027] The temperature field corresponding to each grid cell expressed by the interpolation function is substituted into the weak form corresponding to the energy conservation equation, the humidity field is substituted into the weak form corresponding to the mass conservation equation, and the displacement field is substituted into the weak form corresponding to the momentum conservation equation, to obtain discrete equations respectively;

[0028] The temperature, humidity and displacement of each grid cell are expressed by using the interpolation function;

[0029] The discrete equations are coupled and simulated.

[0030] In some embodiments, when the discrete equations are coupled and simulated:

[0031] The momentum conservation equation is discretized by using the Newmark method, and then coupled and simulated with the discretized energy conservation equation and the discretized mass conservation equation.

[0032] In some embodiments, when the discrete equations are coupled and simulated, a coupling mechanism is introduced, including the relationship between thermal stress and moisture stress, the relationship between temperature and latent heat of vaporization, the fluid mass equation and the fluid continuity equation.

[0033] In the second aspect, the embodiments of the present application provide a device for valve structure simulation based on finite element analysis, which comprises a memory, a processor, and a computer program stored in the memory and executable in the processor, and the computer program comprises steps corresponding to the valve structure simulation method based on finite element analysis.

[0034] In the third aspect, the embodiments of the present application provide a readable storage medium, which stores a terminal program, and the terminal program performs the valve structure simulation method based on finite element analysis when executed.

[0035] According to the above technical solutions, the beneficial effects of the present application are as follows:

[0036] 1、The method of the application can design a geometric model according to the structural parameters of the valve structure and subdivide multiple components, accurately restore the actual structure of the valve, define the material parameters of each component and associate them, so that the model can reflect the real material characteristics, lay a foundation for subsequent accurate analysis, the valve seat and valve core made of different materials have different mechanical properties and heat conductivity, so that the parameters can be accurately set to simulate the interaction in the actual working condition, through mesh division and as a simulation object, the calculation efficiency and accuracy can be improved, and the accuracy of the description of the complex valve structure is ensured; a coupling model of fluid flow, humidity transmission, heat transfer and mechanical deformation is established, factors such as fluid flow, humidity and heat conduction and structural mechanics affecting the valve structure are comprehensively considered, finally the coupling model is imported into the simulation model software for simulation and solution analysis, the simulation is carried out through the establishment of the coupling relationship of multiple physical fields, and advanced methods and optimization strategies are integrated. The valve structure generates heat during operation, humidity change may affect the material properties, and mechanical deformation interacts with other factors, through this multi-physical field coupling analysis, the working state of the valve can be simulated more in real time, and more accurate results can be obtained, so that the real-time performance of the multi-physical field coupling simulation is improved, the working efficiency is ensured, and the accuracy is improved. Through the determination of the simulation results, the grid elements with failure risk can be identified, and the problems existing in the valve structure design can be accurately displayed, so as to be adjusted, and the accuracy of the valve structure is ensured.

[0037] 2、The device of the application can efficiently execute the structure simulation method based on finite element analysis through the computer program stored on the memory and running on the processor, and can quickly perform complex numerical calculation, so that the calculation efficiency of the simulation is greatly improved, and the time cost of the valve structure design is saved.

[0038] 3、The readable storage medium of the application can conveniently store and transfer the above-mentioned valve structure simulation method based on finite element analysis in the form of software, so as to facilitate the development and design of the valve structure. The readable storage medium can execute the above-mentioned valve structure simulation method based on finite element analysis on different devices, is convenient to transfer when the device needs to be replaced, can meet the use demand of different devices. BRIEF DESCRIPTION OF DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiment description will be briefly introduced one by one. Obviously, the drawings in the following description are some embodiments of the present application, and other embodiments can be obtained by those skilled in the art without creative labor based on these drawings. The block diagram shown in the drawings is only a functional entity, which does not necessarily correspond to a physically independent entity, that is, the functional entities can be realized in the form of software, or in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices. The flowchart shown in the drawings is only an exemplary description, which does not necessarily include all contents and operations / steps, and does not necessarily be executed in the order described. For example, some operations / steps can be decomposed, and some operations / steps can be combined or partially combined, so the actual execution order can be changed according to the actual situation.

[0040] Figure 1 An embodiment step schematic diagram of the valve structure simulation method based on finite element analysis of the present application is shown;

[0041] Figure 2 A relationship schematic diagram of the coupling model of multiple physical fields is shown;

[0042] Figure 3 A schematic diagram of the deformation simulation model of the geometric model in the valve structure simulation method based on finite element analysis of the present application is shown. DETAILED DESCRIPTION

[0043] The technical solutions in the embodiments of the present application will be described clearly and completely in the following detailed description of the specific embodiments of the present application with reference to the drawings. The detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the present application, and the described embodiments are only some of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, various different configurations can be arranged and designed, and all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0044] The present application will be described in the following with reference to the drawings and specific embodiments:

[0045] Please refer to Figure 1 The first aspect embodiment of the present application provides the first aspect, and the valve structure simulation method based on finite element analysis is provided in the embodiments of the present application, which comprises:

[0046] S1, design a geometric model according to the structural parameters of the valve structure, and divide the geometric model into multiple components, which are divided according to the combination relationship or action relationship of the valve structure; the valve structure related to the embodiments of the application includes multiple types, including mechanical valves and electric valves, mechanical valves such as ball valves, butterfly valves, check valves, etc., electric valves such as solenoid valves, servo valves, etc., servo valves including electro-hydraulic, pneumatic or hydraulic, electro-hydraulic such as proportional valve, jet pipe valve, etc. The geometric model of the valve structure is preliminarily designed according to performance requirements, such as size requirements, material requirements, and various physical parameter requirements, such as vibration performance, high and low temperature, acceleration, etc., which are determined according to the product application scene requirements, and also need to consider load specifications and design specifications, etc.

[0047] S2, define the material parameters of each component, and associate the material parameters with each component; in this way, the material parameters are associated with different structures of the geometric model of the valve structure, such as hard alloy for the valve core and stainless steel for the valve sleeve, including hardness, elastic modulus and other material parameters, each component is associated with the material parameters; in this way, it not only ensures that the designed geometric model can meet the design requirements, but also can be used to evaluate the performance of the materials of each component in complex environments.

[0048] S3, use finite element simulation model software to divide the geometric model into finite element grids, form grid elements, and use all grid elements as simulation analysis objects; grid division is a common method in existing simulation analysis, and the embodiments also use a conventional grid division method. Through grid division, complex geometric shapes can be divided into multiple simple elements, thereby realizing approximate solution of complex geometric shapes.

[0049] S4, establish a coupling model of the influence of fluid flow, humidity transmission, heat transfer and mechanical deformation on the valve structure; set boundary conditions and initial conditions; introduce the influence of different environmental information on the valve structure, through the establishment of the above coupling model, the important parameters affecting the valve structure are considered, the multi-physical field coupling model is established, and the accurate simulation model of the valve structure is obtained more comprehensively; through the boundary conditions and initial conditions, the constraint conditions of the coupling model can be determined to ensure the uniqueness and stability of the solution, and the stress and deformation in the actual engineering environment can be simulated.

[0050] S5, import the coupling model into the simulation model software for multi-physical field coupling simulation analysis; different physical fields have their own control equations, and these physical fields are related to each other. By importing the coupling model into the simulation model software, the physical fields and the geometric model can be linked, and this process is a conventional simulation method, so that the powerful computing function of the simulation model software can be used to quickly calculate the distribution and relationship of each physical field, and then provide a basis for design. The finite element simulation model software can use conventional analysis software such as ANSYS, SolidWorks, etc.

[0051] S6, according to the simulation result, identify the grid element in the geometric model that exists failure risk, and optimize the design; the simulation model software can quickly calculate the simulation result, and judge the grid element in the geometric model that exists failure risk according to the simulation result, adjust the position of the geometric model corresponding to the grid element that exists failure risk, mark the grid element that exists failure risk as a weak grid element first, then re-adjust the design of the geometric model, optimize, and continue to execute from the beginning of dividing the finite element grid element. Then repeat the above steps S5 and S6 until each grid element of the final geometric model reaches the design standard, here the standard can include various parameters such as stress, safety factor, displacement, deformation, fatigue, etc., and finally there is no weak grid element. The weak grid element refers to the place in the valve structure where the structure is easy to fail, which is the key area that should be optimized and designed. Generally, simulation is judged from several points: high stress value area, that is, stress concentration area, area with too large deformation, area where fatigue hot spot is easy to cause fatigue damage, etc. If there is a weak grid element, it will cause deformation or damage of the valve structure.

[0052] The method of the present application designs a geometric model according to the structural parameters of the valve structure and subdivides multiple components, which can accurately restore the actual structure of the valve, define the material parameters of each component and associate them, so that the model can reflect the true material properties and lay a foundation for subsequent accurate analysis. The valve seat and valve core made of different materials have different mechanical properties and thermal conductivity, so the parameters can be accurately set to simulate the interaction in the actual working condition. Through grid division and as a simulation object, the calculation efficiency and accuracy can be improved to ensure the accuracy of the description of the complex valve structure. A coupling model of fluid flow, humidity transmission, heat transfer and mechanical deformation is established, and factors such as fluid flow, humidity and heat conduction and structural mechanics that affect the valve structure are fully considered. Finally, the coupling model is imported into the simulation model software for simulation and solution analysis. Through the simulation of the multi-physical field coupling relationship, advanced methods and optimization strategies are integrated. The valve structure works will generate heat, humidity changes may affect material properties, and mechanical deformation interacts with other factors. Through this multi-physical field coupling analysis, the working state of the valve can be simulated more in real time, and more accurate results can be obtained, thereby improving the real-time performance of multi-physical field coupling simulation, ensuring the working efficiency while improving the accuracy. Through the determination of the simulation result, the grid element that exists failure risk can be identified, and the problems existing in the valve structure design can be accurately displayed for adjustment, thereby ensuring the accuracy of the valve structure.

[0053] Meanwhile, the application can analyze and evaluate the structure performance of the valve structure in depth by determining the parameters of the optimal valve structure in different environments, and further optimize and improve the design and performance of the valve structure, so as to ensure that the valve structure meets the performance requirements in different application scenarios; the application also comprehensively considers the mechanical properties of the valve structure and various environmental factors, can more accurately design and simulate, can improve the design efficiency of the valve structure, and reduce the development cost of the valve structure.

[0054] In some embodiments, the finite element meshing of the geometric model specifically includes: 1. adaptive mesh refinement: dynamically adjusting the mesh density based on the local physical field intensity to ensure high resolution in critical areas. The dynamic adjustment of the mesh is realized in the following ways: local encryption: increasing the grid resolution in areas with large solution changes; local coarsening: reducing the grid resolution in areas with smooth solution changes; hierarchical meshing: dividing the calculation domain into multiple levels of mesh, each level having different resolution. The key to adaptive mesh refinement is how to determine which areas need to be encrypted or coarsened, which is usually based on error estimation or the gradient of physical quantities. 2. Refinement criteria: error estimation, which estimates the error by comparing the solutions on different meshes to determine which areas need finer meshes; physical field characteristics, areas sensitive to specific physical phenomena, such as high gradient areas in fluids, stress concentration points in structures, etc., should use finer meshes; user-defined criteria, based on engineering experience and design requirements, manually specify certain areas for refinement. Through the above mesh refinement, the mesh density is dynamically adjusted based on the local physical field intensity to ensure high resolution in critical areas; at the same time, multi-scale modeling support is provided, using both coarse and fine meshes in the same model to balance the computational cost and accuracy requirements.

[0055] Please refer to Figure 2 In some embodiments, the coupling model includes: continuity equation of fluid, heat conduction equation, diffusion equation of moisture, and dynamic equation. The continuity equation of fluid is used to describe the motion state of fluid flow; the heat conduction equation is used to describe the temperature change of each component itself caused by environmental heat source and its own Joule heat; the diffusion equation of moisture is used to describe the humidity change of each component itself caused by environmental humidity and its own moisture diffusion; the dynamic equation is used to describe the displacement, velocity, acceleration and stress change of each component of the valve structure. The coupling model involves the interaction between fluid flow, humidity transmission, heat transfer and structure deformation, forming a coupling model of flow, humidity and heat. In order to describe the coupling relationship of these physical fields, a set of coupled partial differential equations need to be solved, and the numerical solution method based on finite element method is an effective tool to handle such complex problems.

[0056] In some embodiments, the dynamic equation is described based on a multi-degree-of-freedom system as a relationship between a displacement vector, a velocity vector, an acceleration vector, and an external force vector, wherein the coefficients of the displacement vector, the velocity vector, and the acceleration vector are a mass matrix, a damping matrix, and a stiffness matrix, respectively. The vibration, impact, and acceleration simulation of the valve structure is often used to analyze the response characteristics of the structure under dynamic load. Based on the dynamic equation, the changes of physical quantities such as displacement, velocity, acceleration, and stress of the system are described. The motion equation based on a multi-degree-of-freedom system (MDOF) can be described as:

[0057]

[0058] wherein M is a mass matrix; C is a damping matrix; K is a stiffness matrix; X(t) is a displacement vector; and are the second and first derivatives of the displacement vector, respectively; F(t) is an external force vector.

[0059] When there is no external excitation, F(t) = 0; when there is vibration excitation, F(t) = F0cos(ω0t); when there is impact excitation, and when there is acceleration excitation, F(t) = at.

[0060] wherein ω0 is the excitation frequency; F0 is the reference value of the external force vector, used as the excitation amplitude; a is the acceleration excitation value; and t is time.

[0061] In some embodiments, when performing simulation analysis of multi-physical field coupling, each equation corresponding to the coupled model is solved to obtain simulation results of temperature distribution, humidity distribution, stress distribution, and displacement distribution, that is, each equation in the coupled model is solved to ultimately calculate the distribution of each physical quantity on each component. Taking a servo valve as an example, simulation analysis through the coupled model can ensure the performance of the geometric model of the valve structure under different working conditions in the design stage, and understand whether the servo valve can meet the flow and pressure control requirements of the system.

[0062] In some embodiments, when solving each equation corresponding to the coupled model, finite element numerical solution is adopted, including:

[0063] S51, introducing the energy conservation equation, the mass conservation equation, the momentum conservation equation, and the coupling mechanism of multi-physical field coupling, wherein the coupling mechanism includes the relationship between the four physical fields of flow, humidity, and heat. The thermal simulation calculation of the servo valve is described by the heat conduction equation to describe the temperature change of the component itself caused by external heat source and its own Joule heat, which is specifically expressed as follows:

[0064]

[0065] where T is the temperature of each component; k is the thermal conductivity of the material; p2 is the material density of each component; C p is the specific heat capacity of the material at normal pressure; Q is the external heat source; is the temperature gradient; T0 is the constant temperature on the boundary; t is time.

[0066] The wet simulation calculation of the servo valve describes the change in the humidity of the component itself caused by external humidity and its own humidity diffusion through the humidity diffusion equation.

[0067]

[0068] where w is the humidity of each component; D is the humidity diffusion coefficient; S 湿 is the humidity source term; t is time; is the humidity gradient.

[0069] Since the servo valve itself is in a humid and hot environment, the material itself will change in parameter characteristics due to the influence of temperature and humidity. In order to analyze the characteristics of each component in the physical structure, mechanical analysis is needed. In order to describe the coupling relationship of these physical fields, the corresponding control equation is derived, and appropriate coupling terms are introduced. The following is the basic theoretical formula derivation of the wet and hot coupling simulation, which covers energy conservation, mass conservation, momentum conservation, and coupling effects.

[0070] The basic equation of fluid flow is:

[0071]

[0072] where V is the velocity field of the fluid; q is the flow rate; k f is the thermal conductivity of the material; μ is the viscosity of the fluid; P is the fluid pressure.

[0073] The continuity equation of the fluid ensures the mass conservation of the fluid, which is:

[0074]

[0075] where V is the velocity field of the fluid; q is the flow rate, which can be used as a fluid source term; Φ is the porosity; t is time; p1 is the fluid density.

[0076] The following constructs the basic equation of structural mechanics, and the strain tensor ε can be derived through the displacement gradient, which is:

[0077]

[0078] where T is the absolute temperature; u is the displacement vector; is the displacement gradient.

[0079] The constitutive relationship between stress and strain is:

[0080] σ = C: ε

[0081] where C is the elastic stiffness tensor; ε is the strain tensor; σ is the stress.

[0082] For the problem of heat and moisture coupling, the energy conservation equation is as follows:

[0083]

[0084] where k(T, ω, P) is the thermal conductivity, affected by temperature T, humidity ω, and pressure P; Q int is the internal heat source term; Q latent is the latent heat source term, representing the heat released or absorbed per unit volume due to phase change; V is the velocity field of the fluid; ρ1 is the fluid density; is the temperature gradient; P is the fluid pressure; ω is the humidity of each component; C p is the specific heat capacity of the material at normal pressure; t is time.

[0085] When the moisture undergoes phase change, it releases or absorbs energy that affects the energy balance and temperature distribution of the system.

[0086]

[0087] where Q latent is the latent heat source term, representing the heat released or absorbed per unit volume due to phase change; L is the latent heat of vaporization of water; ω is the humidity of each component; t is time.

[0088] For the problem of heat and moisture coupling, the mass conservation equation is:

[0089]

[0090] where D(T, ω, P) is the moisture diffusion coefficient, affected by temperature T and humidity ω; V is the fluid velocity; P is the fluid pressure; t is time; S 湿 is the moisture source term.

[0091] Based on the Arrhenius-type model, combining the nonlinear effects of temperature and humidity, the following formulas for thermal conductivity k(T, ω, P) and diffusion coefficient D(T, ω, P) are obtained, and their reliability is determined through simulation calculation and experimental verification.

[0092]

[0093] where E a is the activation energy; represents the effect of temperature on thermal conductivity; R is the gas constant, 8.314 J / (mol·K); n, m are empirical coefficients, usually taking values of 1 or 2; α 敏is the pressure sensitivity coefficient; T is the temperature; ω is the humidity of each component itself; P is the fluid pressure; D0 is the reference diffusion coefficient; k0 is the reference thermal conductivity coefficient.

[0094] For the flow-wetting-thermal coupling problem, the momentum conservation equation is:

[0095]

[0096] where b is the body force; a is the thermal expansion coefficient; β is the humidity expansion coefficient; γ is the pressure sensitivity coefficient; I is the unit tensor; C is the elastic stiffness tensor; ε is the strain tensor; T is the temperature; ω is the humidity of each component itself; ρ is the density, which can be the fluid density ρ1 or the material density ρ2 of each component; u is the displacement; and t is the time.

[0097] S52, discretize the continuous multi-physical field into a finite number of physical field units corresponding to the grid units.

[0098] In order to numerically solve these complex coupling problems, the finite element method (FEM) is usually used to discretize the continuous physical field into a finite number of physical field units, which correspond to the grid units. By simulating the physical field units, the physical field corresponding to the geometric model corresponding to each grid unit can be simulated, and the overall coupling of the multi-physical field can be realized. The multi-physical field can be discretized into a finite number of physical field units, which can be solved by different methods such as finite element method, finite difference method, finite volume method, and boundary element method. For the valve structure of the present application, which has a complex geometry and a multi-physical field coupling problem, the finite element method is used for analysis.

[0099] S53, solve the discretized algebraic equation set of each physical field unit to obtain an approximate solution.

[0100] The discretized algebraic equation set of each physical field unit is a nonlinear partial differential equation. In order to solve the nonlinear partial differential equation, the weak form and the Galerkin method are usually used. The weak form is obtained by multiplying the original partial differential equation by a suitable test function and integrating over the solution domain. The weak form does not require the equation to be strictly satisfied at every point, but is satisfied in the integral sense, which reduces the smoothness requirement of the solution. The weak form facilitates the conversion of the partial differential equation into an integral equation, simplifies the calculation, and provides a suitable solution method for the numerical solution of the multi-physical field problem. The Galerkin method is a method for solving the weak form, which converts the integral equation into an algebraic equation set by selecting the basis function, and provides a suitable solution method for the numerical solution of the multi-physical field problem.

[0101] In some embodiments, solving the discretized algebraic equation set specifically includes:

[0102] S531, the partial differential equations of the energy conservation equation, the mass conservation equation and the momentum conservation equation are converted into integral form by introducing test functions, and the expressions of the weak form are formed respectively.

[0103] Wherein the introduced test functions are δT, δω and δu respectively, the partial differential equations are converted into integral form, and specifically include:

[0104] Weak form of the energy conservation equation:

[0105]

[0106] Wherein Ω is the integral region; ρ is the density, which can be the fluid density ρ1 or the material density ρ2 of each component; C p is the specific heat capacity of the material under normal pressure; T is the ambient temperature; t is time; V is the velocity field of the fluid; ω is the humidity of each component itself; P is the fluid pressure; Q int is the internal heat source term; Q latent is the latent heat source term; is the temperature convection term caused by fluid flow.

[0107] Weak form of the mass conservation equation:

[0108]

[0109] Wherein ω is the humidity of each component itself; t is time; D(T, ω, P) is the moisture diffusion coefficient; is the gradient of the humidity process quantity; is the moisture convection term caused by fluid flow; S 湿 is the moisture source term.

[0110] Weak form of the momentum conservation equation:

[0111]

[0112] Wherein C is the elastic stiffness tensor; ε is the strain tensor; T is the temperature; ω is the humidity of each component itself; ρ is the density, which can be the fluid density ρ1 or the material density ρ2 of each component; u is the displacement; t is time; α 热 is the thermal expansion coefficient; β is the moisture expansion coefficient; γ is the pressure sensitivity coefficient; I is the unit tensor; b is the body force.

[0113] S532, the temperature field corresponding to each grid cell expressed by the interpolation function is substituted into the corresponding weak form of the energy conservation equation, the humidity field is substituted into the corresponding weak form of the mass conservation equation, and the displacement field is substituted into the corresponding weak form of the momentum conservation equation, to obtain discrete equations respectively.

[0114] The temperature field is represented by an interpolation function T(x) and substituted into the weak form to obtain the discretized energy conservation equation:

[0115]

[0116] where ρ is the density, which can be the fluid density ρ1 or the material density ρ2 of each component; C p is the specific heat capacity of the material at normal pressure; N i , N j is the shape function at a certain node position; V is the velocity field of the fluid; k(T, ω, P) is the thermal conductivity of the material; Q int is the internal heat source term; Q latent is the latent heat source term; M is the mass matrix; C 阻 is the damping matrix; K is the stiffness matrix; and T is the ambient temperature.

[0117] The humidity field is represented by an interpolation function ω(x) and substituted into the weak form to obtain the discretized mass conservation equation:

[0118]

[0119] where N i , N j is the shape function at a certain node position; ω is the humidity of each component itself; S 湿 is the humidity source term; M is the mass matrix; and K is the stiffness matrix.

[0120] The displacement field u(x) is represented by an interpolation function and substituted into the weak form to obtain the discretized momentum conservation equation:

[0121]

[0122]

[0123] where ρ is the density, which can be the fluid density ρ1 or the material density ρ2 of each component; N i , N j is the shape function at a certain node position; C 阻 is the damping matrix; u is the displacement vector; b is the body force; M is the mass matrix; K is the stiffness matrix; and t is time.

[0124] S533, represent the temperature, humidity, and displacement of each grid element using interpolation functions.

[0125] The physical fields are interpolated using linear or nonlinear shape functions. Assume that we have a finite element grid containing n nodes, and the unknown quantities (such as temperature T i , humidity ωi and displacement u i ) can be expressed by an interpolation function:

[0126]

[0127] where N i (x) is a shape function, satisfying N i (x) = δ ij (Kronecker delta); x represents the node position, i, j are indexes using integers, representing nodes.

[0128] S534, coupling simulation solving is performed on each discretized equation.

[0129] When coupling simulation solving is performed on the discretized equations, mainly, an equation group composed of multiple interrelated equations is processed, and various solving methods can be used, such as simultaneous direct solving, iterative solving, etc. For a relatively small scale and strong coupling equation group, all discretized equations can be combined to form a large equation group for solving. For a large-scale equation group, especially when the coupling between equations is not very tight, or the coupling relationship can be simplified by appropriate methods, an iterative solving method can be used. The present application uses the above intelligent coupling algorithm, uses a new type of iterative solver, combines preconditioning technology and relaxation factor optimization, and accelerates the convergence process.

[0130] In some embodiments, when coupling simulation solving is performed on each discretized equation:

[0131] The momentum conservation equation is discretized by using the Newmark method, and then coupled with the discretized energy conservation equation and the discretized mass conservation equation for simulation solving. The Newmark method is a commonly used implicit time integration method, which is widely used in numerical solving of structural dynamics and fluid-structure coupling problems, is suitable for second-order ordinary differential equations (such as the momentum conservation equation), and has good numerical stability and accuracy. In the problem of fluid-thermal-moisture coupling, the Newmark method can be used to discretize the momentum conservation equation, and combined with the discretization method of other physical fields (such as temperature field and humidity field), the multi-physical field coupling simulation can be realized. Specifically:

[0132] When discretizing the momentum conservation equation, the Newmark method is used to discretize the momentum conservation equation to obtain the acceleration, displacement and velocity at time step t n+1 .

[0133]

[0134] where u n , respectively, denote displacement, velocity, acceleration; Δt is time step; β and γ are Newmark method parameters, usually β = 0.25, γ = 0.5.

[0135] The acceleration equation at time step t n+1 is obtained as:

[0136]

[0137] where M is mass matrix; K is stiffness matrix; C 阻 is damping matrix; is acceleration; Δt is time step; γ is pressure sensitivity coefficient; u n is unique; β is wet expansion coefficient; F n+1 is n+1 time step external force vector.

[0138] The discretization of energy conservation equation and mass conservation equation is carried out.

[0139] The discretization format of energy conservation equation is:

[0140]

[0141] where ρ is density, which can be fluid density ρ1 or material density ρ2 of each component; C p is specific heat capacity of material under normal pressure; T n is n time step temperature; Δt is time step; V is velocity field; k(T n+1 , ω n+1 , P n+1 ) is thermal conductivity of material; q int is internal heat source term; Q latent is latent heat source term.

[0142] The discretization format of mass conservation equation is:

[0143]

[0144] where ω n is humidity at n time step; Δt is time step; D(T n+1 , ω n+1 , P n+1 ) is moisture diffusion coefficient at n+1 time step; S 湿 is moisture source term.

[0145] In order to solve the above control equations, appropriate boundary conditions and initial conditions need to be specified. The initial conditions include the initial temperature, humidity, displacement and fluid pressure distribution inside the material, and the common boundary conditions include:

[0146] Temperature boundary condition: specify the temperature or heat flux of the material surface; such as the ambient temperature and the material surface temperature is 30℃.

[0147] Humidity boundary condition: specify the humidity or moisture flux of the material surface; such as the relative humidity of the ambient and the material surface is 85%.

[0148] Mechanical boundary condition: specify the displacement or stress of the material surface; such as the fixed connection part of the servo valve is set as a fixed constraint position; the wall surface is set as a no-slip wall condition.

[0149] Fluid boundary condition: specify the inlet pressure, outlet pressure or flow rate of the fluid; such as the fluid inlet pressure is 7MPa and the fluid outlet pressure is 0MPa.

[0150] Convert the loading conditions such as acceleration, impact and vibration into action load mode for loading; such as the overall acceleration is 50g and the direction is respectively applied in X, Y and Z axial directions.

[0151] Couple the above discretized momentum conservation equation with the discretized energy conservation equation and the discretized mass conservation equation for simulation solving, and the above arrangement obtains:

[0152]

[0153] Wherein: M is the mass matrix; K is the stiffness matrix; C 阻 is the damping matrix; γ is the pressure sensitivity coefficient; Δt is the time step; β is the wet expansion coefficient;

[0154] In some embodiments, when coupling simulation solving is performed, a coupling mechanism is introduced, including the relationship between thermal stress and wet stress, the relationship between temperature and latent heat of vaporization, fluid mass equation and fluid continuity equation.

[0155] In the coupled hygro-thermal problem, the changes of temperature, humidity and stress will interact with each other and jointly act on the mechanical properties of the material. Therefore, a coupling term needs to be introduced to describe these interactions.

[0156] Mechanical analysis is mainly based on elastic mechanics, and its related equation groups include balance equation, displacement equation and thermal stress-thermal strain relationship as follows:

[0157]

[0158] Wherein, ρ is the density, which can be the fluid density ρ1 or the material density ρ2 of each component; μ is the damping coefficient; is the displacement vector; is the applied stress; is the elastic relationship, and is a differential operator, is thermal strain or moisture strain caused by temperature or humidity change; is a stress vector; is strain; is thermal stress.

[0159] Based on the law of conservation of energy, the moisture-heat coupling model, the change of temperature and humidity will affect each other, which will cause thermal stress and moisture stress inside the material, affecting the mechanical properties of the material. For example, temperature rise may cause the material to increase its hygroscopicity, and humidity increase will cause the material to swell, and then produce moisture stress. These stresses are superimposed with mechanical stress, forming a complex coupling effect, thermal stress and moisture stress can establish a coupling mechanism through moisture-heat stress:

[0160] σ thermo-hygral = α 热 TI+ βωI

[0161] Where, σ thermo-hygral is moisture-heat coupling stress; α 热 is the thermal expansion coefficient; β is the moisture expansion coefficient; I is the unit tensor; T is the ambient temperature; ω is the humidity of each component itself.

[0162] When the moisture in the material undergoes phase change (such as evaporation, condensation), it will be accompanied by the release or absorption of latent heat, affecting the distribution of temperature field. The phase change effect can be established by introducing a latent heat term to establish a coupling mechanism:

[0163]

[0164] Where, Q latent is the latent heat source term; L is the latent heat of vaporization of water; ω is the humidity of each component itself; t is time.

[0165] Fluid flow will affect the deformation of solid structure, and vice versa; fluid-structure coupling can be realized through the fluid pressure term P in the momentum conservation equation and the solid displacement term u.

[0166] When analyzing the flow channel of a servo valve, the control equation of fluid flow needs to be solved. Starting from the mass conservation, the continuity equation can be expressed as:

[0167]

[0168] Where, ρ1respectively represents the velocity and density of the fluid; t is time.

[0169]

[0170] Where, ρ1is the fluid density; P is the fluid pressure, υ is the viscosity of the fluid, represents the vector acceleration due to gravity; is the displacement vector; t is time.

[0171] In some embodiments, in the multi-physics coupled simulation, parameterized optimization aims to achieve specific goals (such as minimizing stress, maximizing efficiency, etc.) by optimizing design parameters. Genetic Algorithm (GA) is a commonly used global optimization method, which is suitable for finding the best combination of design parameters for complex problems. For the design problem of servo valve, it is necessary to optimize its geometric parameters (such as flow passage width, valve body thickness, etc.) so that the performance indicators (such as flow rate, pressure loss, structural stress, etc.) of the servo valve reach the optimal under given working conditions.

[0172] Genetic Algorithm simulates the natural selection and genetic mechanism, and searches for the optimal solution by simulating the evolutionary process. The main steps include: initialization of population: randomly generate a set of initial solutions (individuals), each individual represents a possible design scheme. Evaluate fitness: calculate the fitness value of each individual according to the predefined objective function. Selection: select individuals into the next generation according to the fitness value. Crossover: generate new individuals by exchanging part of the genetic information. Mutation: randomly change some genes to increase the diversity of the population. Termination condition: stop iteration when certain conditions are met (such as reaching the maximum number of iterations or finding a satisfactory solution). The specific implementation steps are as follows:

[0173] First, define an objective function to evaluate the pros and cons of each design scheme. For servo valve design, optimize its design parameters, including flow passage width and valve body thickness. The goal can be to consider multiple performance indicators, such as minimizing pressure loss and maximizing flow rate. Then create an initial population, each individual consisting of a set of design parameters. Select individuals into the next generation according to the fitness value. Generate new individuals by exchanging part of the genetic information. Randomly change some genes to increase the diversity of the population. Integrate the above steps into the main loop until the termination condition is met. Through the above genetic algorithm and parameter optimization method, the best combination of design parameters can be automatically found.

[0174] In the above step S6, when judging the grid elements in the geometric model that have failure risks, the grid elements that have failure risks are marked as weak grid elements, and whether a certain grid element belongs to a weak grid element is usually based on the threshold value of key parameters such as stress, strain or deformation.

[0175] Based on the commonly used Von Mises stress, safety factor M s , displacement and deformation, fatigue analysis of the valve to determine which grid elements are considered weak, specifically including:

[0176] 1. Von Mises stress: If the Von Mises stress σ VM of a certain mesh element exceeds the yield strength σ y of the material, the element is considered as a weak mesh element. For example, if the yield strength of a certain valve is 1550 MPa, compare the stress of the mesh element with the yield strength. If the stress is less than the yield strength, the design is qualified. Otherwise, mark the mesh element as a weak mesh element.

[0177] 2. Safety margin (M s ): The ratio of the design stress to the actual working stress, which is used to measure the safety margin of the structure.

[0178] Generally, M s should be greater than 1; for critical components and high-risk applications, it is recommended that M s be at least 1.2 to 1.35; if the M s of certain elements is less than this range, these elements can be considered as weak mesh elements.

[0179] Ensure that the safety margin M s of the servo valve is at least 1.2.

[0180]

[0181] Where [σ] is the allowable stress, MPa, based on the strength limit for brittle materials and the yield limit for plastic materials; the value is 1550 MPa; f is the safety factor, dimensionless, the safety factor for quasi-static load is generally taken as 1.5, and the safety factor for vibration load is generally taken as greater than or equal to 1.2; the value is 1.2; σ max is the maximum stress value, MPa; to meet the safety margin of the servo valve, the maximum stress value of the mesh element should be less than 1076.39 MPa.

[0182] 3. Displacement and deformation: Set reasonable displacement limits according to design requirements and operating conditions. For example, in a precision servo system, any displacement exceeding microns may not be acceptable.

[0183] Through finite element analysis, calculate the deformation of each component of the servo valve under the action of the coupled stress field, and compare it with the design displacement field obtained from each part according to the design standard. If it is less than, the design of the part is qualified, otherwise it is not qualified.

[0184] 4. Fatigue analysis: For components such as servo valves that often bear cyclic loads, fatigue damage also needs to be considered. If the predicted life is lower than the expected service life, it indicates a risk of fatigue failure, and the relevant mesh elements should be considered as weak mesh elements.

[0185] For this servo valve, the design life is 107 The fatigue life of a material under cyclic loading is evaluated by using the SN curve (stress-life curve). If the predicted fatigue life is lower than the design requirement, it is considered that there is a risk of fatigue failure and is marked as a weak mesh element.

[0186] Determining which mesh elements in a servo valve are weak depends on specific engineering requirements, material properties, and the application environment. Only by comprehensively applying the methods described above and conducting detailed analysis with professional knowledge can we effectively identify and improve mesh elements at risk of failure in the design, followed by a redesign optimization.

[0187] As in the embodiments of this application, the deformation of the servo valve structure under combined stress is calculated through finite element analysis, and the maximum displacement X is obtained. max The design displacement X of each structural component is compared with the design displacement X of the component. If the displacement is less than X, the structural component design is qualified; otherwise, the design is unqualified. Furthermore, the safety margin of each structural component must be at least greater than 1.2. Figure 3 As shown, the final calculation results for the servo valve body are as follows: the horizontal forward displacement is 0.0049 mm; the horizontal lateral displacement is 0.0012 mm; the vertical downward displacement is 0.0019 mm; the maximum peak stress on the valve body is 67.078 MPa. Based on its material properties (the yield stress of aluminum alloy is 260 MPa), the safety margin for the maximum stress can be calculated to be 3, further verifying the reliability of the servo valve assembly in terms of strength and stiffness. Under some extreme operating conditions, such as extreme high and low temperatures, random vibration, and large acceleration, the servo valve may have certain limitations. Therefore, when designing the servo valve structure, each component of the servo valve must have sufficient margin to ensure the structural strength and stability of the servo system under abnormal operating conditions.

[0188] A second aspect of this application provides an apparatus for simulating valve structures based on finite element analysis, including a memory, a processor, and a computer program stored in the memory and executable in the processor. The computer program includes the steps corresponding to the valve structure simulation method based on finite element analysis described above. When the processor executes the computer program, it implements the steps in the method embodiments described above, for example... Figure 1 The steps shown; or, when the processor executes the computer program, it implements the functions of each module / unit in the embodiments of the device for valve structure simulation based on finite element analysis described above. It should be understood that the devices of the various embodiments of this application can be implemented based on memory and processor, each memory being used to store a computer program for executing the methods described above in this application, and the processor executing the computer program, so that the device for valve structure simulation based on finite element analysis implements the methods of the various embodiments described above.

[0189] The computer program stored on the memory and running on the processor can efficiently perform the structure simulation method based on finite element analysis, can quickly perform complex numerical calculation, and greatly improves the calculation efficiency of simulation and saves the time cost of valve structure design.

[0190] In some embodiments, the device for valve structure simulation based on finite element analysis can be a desktop computer, a notebook computer, an industrial computer, a palm computer, a tablet computer or other mobile terminal, and a cloud server and the like computer equipment, and is not limited to what operating system is carried. The device for valve structure simulation based on finite element analysis can include, but is not limited to, a processor and a memory. Those skilled in the art can understand that the examples of the device for valve structure simulation based on finite element analysis do not constitute a limitation on the device for valve structure simulation based on finite element analysis, and can include more or fewer components than the examples, or combine certain components or different components, for example, the device for valve structure simulation based on finite element analysis can also include an input device, an output device, a network access device, a bus and the like.

[0191] In a third aspect, the present application provides a readable storage medium, which stores a terminal program. When the terminal program is executed, the valve structure simulation method based on finite element analysis is performed. The modules / units of the valve structure simulation method based on finite element analysis are realized in the form of software function units and sold or used as independent products. The modules / units can be stored in a readable storage medium. Based on such understanding, the present application realizes all or part of the processes of the above-mentioned embodiments, and can also be completed by a computer program instructing related hardware. The computer program can be stored in a readable storage medium. When the computer program is executed by a processor, the steps of each method in the above-mentioned embodiments can be realized. When the computer program is executed by the processor, the specific implementation of each step and the generated technical effects are the same as those of the above-mentioned method embodiments. For brief description, the above-mentioned embodiments are not mentioned in this embodiment, and the corresponding content of the above-mentioned method embodiments can be referred to.

[0192] The readable storage medium can store the valve structure simulation method based on finite element analysis in the form of software, which is convenient for storage and transfer. This is convenient for the development and design of valve structure, the readable storage medium can execute the valve structure simulation method based on finite element analysis on different devices, and is convenient for transfer when the device needs to be replaced, and can meet the use requirements of different devices.

[0193] Regarding the specific embodiments of the present application, it should be noted that:

[0194] In the description of the present application, the embodiments of the present application can be realized in electronic hardware, computer program products, or a combination of computer software and electronic hardware, and are described with reference to flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of flows and / or blocks in the flowcharts and / or block diagrams can be realized by instructions. The above computer program can be loaded in a computer, stored in a computer readable storage medium capable of guiding the computer or other programmable data processing device to work in a specific way, so that the instructions of the computer program perform a series of operation steps to generate a computer-implemented process, generate a manufacture product including an instruction device, realize the functions specified in one or more flows and / or blocks, or realize the functions specified in one or more flows and / or blocks. Figure 1 one or more flows and / or blocks Figure 1 one or more flows and / or blocks The computer readable storage medium can include any entity or device capable of carrying the computer program code, a U disk, a mobile hard disk, a magnetic disk, an optical disk, a computer memory, a read-only memory, a random access memory, an electrical carrier signal, a telecommunication signal, a software distribution medium, or other recording media, etc. For example, a hard disk, a memory, an optical storage, a plug-in hard disk, a memory card, a secure digital card, a flash memory card, or at least one magnetic disk storage device, a flash memory device, or other volatile solid-state memory device.

[0195] In the description of the present application, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, device or readable storage medium including a series of elements not only includes those elements, but also includes other elements not explicitly listed that meet the concept of the present application, or further includes the elements inherent to such process, method, device or readable storage medium. Without more limitations, the element defined by the statement "including a" does not exclude the presence of other elements in the process, method, device or readable storage medium including the element.

[0196] In the description of the present application, the description with reference to the terms "some embodiments", "optional embodiments", "examples", "specific examples", "optional examples" or "optional embodiments" means that the specific features, structures, materials or characteristics described in conjunction with the embodiments or examples are included in at least one embodiment or example of the present application, but do not mean that all possible forms of the present application are described and explained by these embodiments. In the present specification, the illustrative description of the above terms is not necessarily directed 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. In addition, those skilled in the art can combine and combine different embodiments or examples described in the specification.

[0197] In addition, the technical solutions among various embodiments can be combined with each other, but must be based on that a person skilled in the art can realize. Although the embodiments of the present application have been shown and described, various changes, modifications, replacements and variations can be made to these embodiments without departing from the principles and purposes of the present application, and a person skilled in the art can understand that various other specific changed and combined embodiments are made according to the technical inspirations disclosed in the present application without departing from the essence of the present application, and still fall within the protection scope defined by the claims of the present application and equivalent technical solutions.

[0198] Meanwhile, the technical solutions among various embodiments can be combined with each other, but must be based on that a person skilled in the art can realize, when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, and is not within the protection scope required by the present application.

Claims

1. A method of valve structure simulation based on finite element analysis, characterized in that, The application relates to a method for simulating a valve structure. The method comprises the following steps: designing a geometric model according to structural parameters of the valve structure, and dividing the geometric model into multiple components; defining material parameters of each component, and associating the material parameters with each component; dividing the geometric model into grid cells by using a finite element simulation model software, and taking all the grid cells as simulation analysis objects; establishing a coupling model for influences of fluid flow, humidity transmission, heat transfer and mechanical deformation on the valve structure, and setting boundary conditions and initial conditions; importing the coupling model into the simulation model software, and performing simulation analysis of multiple physical field coupling; according to simulation results, identifying grid cells with failure risks in the geometric model, and optimizing design. The coupling model comprises: a continuity equation of fluid, which is used for describing a motion state of fluid flow; a heat conduction equation, which is used for describing temperature changes of each component caused by environmental heat sources and self Joule heat; a humidity diffusion equation, which is used for describing humidity changes of each component caused by environmental humidity and self humidity diffusion; 2. The finite element analysis-based valve structure simulation method according to claim 1, characterized by, a dynamic equation, which is used for describing displacement, velocity, acceleration and stress changes of each component of the valve structure.

3. The finite element analysis-based valve structure simulation method according to claim 2, characterized by, The dynamic equation is described based on a multiple degree of freedom system as a relationship among displacement vectors, velocity vectors, acceleration vectors and external force vectors, wherein coefficients of the displacement vectors, the velocity vectors and the acceleration vectors are mass matrix, damping matrix and stiffness matrix respectively.

4. The finite element analysis-based valve structure simulation method according to claim 3, characterized by, When the simulation analysis of multiple physical field coupling is performed, each equation of the coupling model is solved to obtain simulation results of temperature distribution, humidity distribution, stress distribution and displacement distribution. When each equation of the coupling model is solved: energy conservation equations, mass conservation equations and momentum conservation equations of multiple physical field coupling are introduced, and a coupling mechanism is introduced; continuous multiple physical fields are discretized into a limited number of physical field units corresponding to the grid cells; 5. The finite element analysis-based valve structure simulation method according to claim 4, characterized by, approximate solutions are obtained by solving discrete algebraic equations of each physical field unit.

6. The finite element analysis-based valve structure simulation method according to claim 4, characterized by, The coupling mechanism is introduced by balancing equations, displacement equations and thermal stress-strain equations to establish relationship formulas of temperature, humidity and stress; by thermal stress and humidity stress to establish relationship formulas of stress changes caused by temperature and humidity; by adding latent heat terms to establish relationship formulas of phase change effects; and by continuity equations and mass conservation equations to establish relationship formulas of fluid pressure, density and flow rate. Solving the discrete algebraic equations specifically comprises: partial differential equations of the energy conservation equations, the mass conservation equations and the momentum conservation equations are converted into integral forms by introducing test functions to form weak form expressions respectively; temperature fields of each grid cell expressed by interpolation functions are substituted into the weak forms of the energy conservation equations, humidity fields are substituted into the weak forms of the mass conservation equations, and displacement fields are substituted into the weak forms of the momentum conservation equations to obtain discrete equations respectively; temperatures, humidities and displacements of each grid cell are expressed by using interpolation functions; 7. The finite element analysis-based valve structure simulation method according to claim 6, characterized by, the discrete equations are coupled and simulated. When the discrete equations are coupled and simulated: The momentum conservation equation is discretized by using the Newmark method, and is coupled with the discretized energy conservation equation and the discretized mass conservation equation to perform simulation solving.

8. The finite element analysis-based valve structure simulation method according to claim 6, characterized by, When the simulation solving is performed, a coupling mechanism is introduced, including the relationship between thermal stress and wet stress, the relationship between temperature and latent heat of vaporization, a fluid mass equation, and a fluid continuity equation.

9. An apparatus for simulation of valve structure based on finite element analysis, comprising a memory, a processor, and a computer program stored in the memory and executable in the processor, characterized in that, The computer program includes steps corresponding to the valve structure simulation method based on finite element analysis as claimed in any one of claims 1-8. 10.A readable storage medium, storing a terminal program, characterized in that, The terminal program performs the valve structure simulation method based on finite element analysis as claimed in any one of claims 1-8 when executed.

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