ABAQUS-based tube plate welding seam electron beam welding numerical simulation method and equipment and medium

Abstract

The invention discloses an ABAQUS-based tube plate welding seam electron beam welding numerical simulation method and device and a medium, and the method comprises the following steps: S1, establishing a heat exchange tube and tube plate three-dimensional geometric model, and inputting material components to calculate material performance parameters; s2, meshing is conducted on the geometric model, material parameters, contact conditions and boundary conditions are converted and set, a welding heat source is applied to a weld joint, and a finite element model in the actual welding process is established; s3, calculating a welding temperature field, comparing with an actual molten pool, and carrying out iterative calculation to obtain a welding simulation result; s4, calculating welding residual stress and deformation distribution of the welding structure; and S5, welding deformation under different welding sequences is calculated and analyzed, and welding process parameters are obtained according to the deformation amount. According to the method, the finite element model of the tube plate welding structure is established, the heat source checking model is applied, and the welding deformation under different welding sequences is analyzed, so that the overall welding deformation is reduced, and the welding quality and manufacturing precision requirements of the tube plate of the steam generation unit are ensured.

Description

Technical Field

[0001] The invention relates to the technical field of welding process numerical simulation, and in particular to an ABAQUS-based tube-sheet weld electron beam welding numerical simulation method, equipment and medium. Background Art

[0002] Tube sheet welding is an important connection process and is often used in the manufacture of heat exchangers, chemical reactors, towers and other equipment. The quality of the weld is crucial to the safety and reliability of the equipment. The steam generator is a heat exchange device that generates steam for the steam turbine. Its steam generating unit is the core component of the steam generator, which consists of a tube sheet, a heat transfer tube and other components. The manufacturing process of the steam generating unit involves a large number of electron beam welding work of annular welds between the tube sheet and the heat transfer tube. As a key manufacturing process of the steam generating unit, the tube sheet welding of the steam generating unit has a large number of welds, a wide welding area, high welding difficulty and high welding requirements. However, the parts are subjected to uneven heating during welding, which will inevitably cause post-weld deformation. Due to the accumulation of multiple tube sheet welding deformations during the manufacturing process, the overall dimensional deviation of the assembly will eventually occur, affecting the processing, assembly and molding quality of the subsequent processes of the unit. Therefore, it is necessary to develop the tube sheet welding process and control the welding deformation.

[0003] In the development of traditional welding processes, a large number of process tests and comparative analyses are required to obtain process parameters with smaller welding deformation. Not only is the development cycle long and the test cost high, but the mechanism and law of welding deformation control are difficult to study in depth, welding residual stress cannot be accurately predicted in advance, and post-welding deformation cannot be accurately controlled. With the improvement of computer computing power and the development of finite element technology, finite element simulation of welding process has gradually been applied to welding process research and development, improving process research and development efficiency and welding quality.

[0004] At present, welding simulation methods have been widely used in the research and development of welding structural parts in the fields of shipbuilding, aerospace, petrochemicals, etc. However, for the welding of titanium alloy tube sheets for steam generators in the nuclear energy field, there is no welding simulation model, calculation process and simulation method based on general finite element analysis software.

[0005] In view of this, this application is hereby filed. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a tube sheet weld electron beam welding numerical simulation method, equipment and medium based on ABAQUS. Aiming at the tube sheet weld electron beam welding process in the manufacture of steam generating units, a welding process simulation model and process based on ABAQUS are established. By establishing a finite element model of the tube sheet welding structure, applying and verifying the heat source model, carrying out a study on the thermal-mechanical coupling numerical simulation calculation of the welding process under different welding sequences, completing the simulation calculation of the welding temperature field and the stress-strain field in turn, and analyzing the temperature change trend, stress distribution and welding deformation distribution in the welding process, thereby reducing the welding test cost and time, providing theoretical reference and data support for the rapid iteration of the welding process, and guiding the subsequent process parameter optimization.

[0007] The present invention is achieved through the following technical solutions:

[0008] In a first aspect, the present invention provides a tube-to-sheet weld electron beam welding numerical simulation method based on ABAQUS, comprising the following steps:

[0009] S1, geometric model establishment and model input parameter acquisition

[0010] According to the actual size, the 3D geometric model of the heat exchange tube and tube sheet is established in the ABAQUS-Part module through stretching, rotation, sweeping and other means. The base material of the weldment is titanium alloy, and there is a gap fit between the heat transfer tube and the tube sheet. The material composition is input into the software JMatpro to calculate the material mechanical performance parameters and thermophysical performance parameters that change with temperature.

[0011] S2, finite element modeling

[0012] Based on the geometric model of S1, meshing is performed to obtain a structural mesh model, and different mesh unit types are assigned. By converting and setting material parameters, contact conditions, boundary condition parameters, and applying welding heat source at the weld, a finite element model of the actual welding process is established.

[0013] S3, temperature field calculation analysis and heat source verification

[0014] Based on the finite element model of S2, the welding temperature field is calculated in ABAQUS to obtain the temperature distribution at different times and positions. By comparing the temperature of the actual molten pool with that of the simulation model, the welding heat source is checked, and the calculation is repeated iteratively to obtain welding simulation results that are more in line with the actual situation.

[0015] S4, mechanical field calculation analysis

[0016] Based on the temperature field results of S3, the sequential coupling method of thermal-mechanical coupling is used to calculate the welding stress-strain distribution of the welded structure, and then the welding residual stress and welding deformation distribution are obtained;

[0017] S5, Welding Sequence Analysis

[0018] Based on the calculation process of S3 and S4, by applying welding heat source to the weld at different times, the welding deformation under different welding sequences is calculated and analyzed, and the welding process parameters are obtained according to the overall deformation amount.

[0019] In a specific embodiment, in step S1, the mechanical property parameters and thermophysical property parameters of the material include elastic modulus, Poisson's ratio, thermal expansion coefficient, thermal conductivity, specific heat capacity, density and yield strength.

[0020] In a specific embodiment, in step S2, the finite element mesh division of the geometric model is specifically as follows: gradual mesh division is performed based on the geometric model, a fine mesh size is used in the annular weld area and its vicinity, and a sparse mesh distribution is used in the area away from the welding layer, and the mesh size gradually increases.

[0021] In a specific embodiment, step S2 also includes an analysis step setting, which is as follows: every two steps of the entire welding process are set as a heat source heating step and a post-weld cooling step, the heat source heating step is started at the beginning of welding, and the post-weld cooling step is performed for a period of time after the welding is completed, and the welding of the next weld is repeated, and finally a cooling analysis step is performed after the welding is completed.

[0022] In a specific implementation, in step S2, the boundary condition setting includes thermal boundary condition setting and mechanical boundary condition setting.

[0023] In a specific implementation, the welding thermal boundary conditions are set as follows:

[0024] The initial temperature of the welding structure and the ambient temperature are both defined as 20°C;

[0025] Combine heat convection and heat radiation conditions into heat transfer boundaries;

[0026] The same heat transfer boundary conditions are set for all external surfaces of the model.

[0027] In a specific embodiment, the welding mechanical boundary conditions are set as follows: the translational degrees of freedom in the X, Y, and Z directions of the fixture area are constrained in the simulation model, and after the fixture constraints are released after welding, three-point constraints are applied to the overall structure.

[0028] In a specific implementation, in step S2, a welding heat source is applied based on a heat source subroutine to heat the weld, a Gaussian heat source model is adopted as the heat source model, and the calculation files include an ini heat source file, an ini trajectory file, an ini heat source and trajectory association file, a dll heat source compilation file, an inp model input file, an env environment file, and a bat batch processing file.

[0029] In a specific implementation, step S3 is as follows:

[0030] The initial values ​​of the heat source parameters are defined based on the weld size and empirical criteria. The initial calculation results of the temperature field are obtained after submitting the transient analysis solution. The molten pool morphology of the preliminary simulation results is compared with the actual welding molten pool size. The heat source parameters are continuously adjusted and iteratively calculated. Finally, a heat source model close to the actual molten pool shape is obtained by verification.

[0031] In a specific implementation, step S4 is as follows:

[0032] The thermo-elastic-plastic finite element method with thermal-mechanical sequential coupling is used to analyze and calculate the welding mechanical field. The obtained welding temperature field simulation results are imported into the network model to calculate the stress-strain field, and finally the welding residual stress and welding deformation are obtained.

[0033] In a second aspect, the present invention further provides an electronic device comprising:

[0034] processor;

[0035] Memory;

[0036] and a computer program, wherein the computer program is stored in the memory, the computer program comprising instructions, which, when executed by the processor, cause the electronic device to perform the simulation method.

[0037] In a third aspect, the present invention further provides a computer-readable storage medium, wherein the computer-readable storage medium includes a stored program, wherein when the program is executed, the device where the computer-readable storage medium is located is controlled to execute the simulation method.

[0038] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0039] 1. The ABAQUS-based tube-sheet weld electron beam welding numerical simulation method, equipment and medium provided in the embodiment of the present invention establish a welding process simulation model and process based on ABAQUS, establish a tube-sheet welding structure finite element model, apply and verify the heat source model, carry out the thermal-mechanical coupling numerical simulation calculation research of the welding process under different welding sequences, complete the simulation calculation of the welding temperature field and stress-strain field in turn, analyze and obtain the temperature change trend, stress distribution and welding deformation distribution during the welding process, thereby reducing the welding test cost and time, providing theoretical reference and data support for the rapid iteration of the welding process, and guiding the subsequent process parameter optimization;

[0040] 2. The ABAQUS-based numerical simulation method, equipment and medium for electron beam welding of tube sheet welds provided in the embodiment of the present invention can accurately calculate the temperature field and stress-strain field results during the electron beam welding of the tube sheet welds of the steam generating unit after heat source verification, and quickly obtain the deformation trend after welding, which can provide theoretical guidance for the optimization of the welding process parameters in the next step. At the same time, by analyzing the welding deformation under different welding sequences, the overall welding deformation can be reduced, which can reduce the welding test cost and time, provide data support for welding process optimization, effectively guide actual welding production, accelerate welding process optimization iteration, and ensure the welding quality and manufacturing precision requirements of the tube sheet of the steam generating unit; effectively guide actual welding production and ensure the welding quality and manufacturing precision requirements of the tube sheet of the steam generating unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0042] Figure 1 A schematic diagram of a technical route of a welding simulation method provided by an embodiment of the present invention;

[0043] Figure 2 A schematic diagram of the geometric structure of a tube sheet provided in an embodiment of the present invention;

[0044] Figure 3 A grid partitioning model diagram provided by an embodiment of the present invention;

[0045] Figure 4 A schematic diagram of three-point constraint positions provided in an embodiment of the present invention;

[0046] Figure 5 A composition diagram of a heat source application calculation file provided in an embodiment of the present invention;

[0047] Figure 6 A schematic diagram showing a comparison between an actual molten pool of a tube sheet and a simulation provided in an embodiment of the present invention;

[0048] Figure 7 The equivalent stress cloud diagram after welding provided by the embodiment of the present invention;

[0049] Figure 8 A schematic diagram of a welding sequence provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments. The illustrative embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0051] In the following description, a large number of specific details are set forth in order to provide a thorough understanding of the present invention. However, it is apparent to one of ordinary skill in the art that these specific details need not be employed to practice the present invention. In other embodiments, in order to avoid obscuring the present invention, well-known materials or methods are not specifically described.

[0052] Throughout the specification, references to "one embodiment," "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in conjunction with the embodiment or example is included in at least one embodiment of the present invention. Therefore, the phrases "one embodiment," "an embodiment," "an example," or "an example" appearing in various places throughout the specification do not necessarily all refer to the same embodiment or example. In addition, particular features, structures, or characteristics may be combined in one or more embodiments or examples in any suitable combination and / or subcombination. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0053] The "range" disclosed in the present application is defined in the form of a lower limit and an upper limit, and a given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundaries of the particular range. The range defined in this way can be inclusive or exclusive of the end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a range. For example, if a range of 60 to 120 and 80 to 110 is listed for a particular parameter, it is understood that a range of 60 to 110 and 80 to 120 is also expected. In addition, if the minimum range values ​​1 and 2 are listed, and if the maximum range values ​​3, 4 and 5 are listed, the following ranges can all be expected: 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4 and 2 to 5. In the present application, unless otherwise specified, the numerical range "a to b" represents an abbreviation of any real number combination between a and b, where a and b are both real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0054] If there is no special explanation, all steps of the present application can be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), which means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0055] At present, welding simulation methods have been widely used in the research and development of welding structural parts in the fields of shipbuilding, aerospace, petrochemicals, etc. However, for the welding of titanium alloy tube sheets for steam generators in the nuclear energy field, there is no welding simulation model, calculation process and simulation method based on general finite element analysis software.

[0056] In order to solve the above technical problems:

[0057] In a first aspect, the present invention provides a tube-to-sheet weld electron beam welding numerical simulation method based on ABAQUS, comprising the following steps:

[0058] S1, geometric model establishment and model input parameter acquisition

[0059] According to the actual size, the 3D geometric model of the heat exchange tube and tube sheet is established in the ABAQUS-Part module through stretching, rotation, sweeping and other means. The base material of the weldment is titanium alloy, and there is a gap fit between the heat transfer tube and the tube sheet. The material composition is input into the software JMatpro to calculate the material mechanical performance parameters and thermophysical performance parameters that change with temperature.

[0060] S2, based on the geometric model of S1, meshing is performed to obtain a structural mesh model, different mesh unit types are assigned, and a finite element model of the actual welding process is established by converting and setting material parameters, contact conditions, boundary condition parameters, and applying welding heat source at the weld;

[0061] S3, based on the finite element model of S2, the welding temperature field is calculated in ABAQUS to obtain the welding simulation temperature distribution at different times and positions;

[0062] S4, based on the temperature field results of S3, the sequential coupling method of thermal-mechanical coupling is used to calculate the welding stress-strain distribution of the welded structure, and then the welding residual stress and welding deformation distribution are obtained;

[0063] S5, based on the calculation process of S3 and S4, applies welding heat source to the weld at different times, calculates and analyzes the welding deformation under different welding sequences, and obtains the welding process parameters according to the overall deformation amount.

[0064] In a specific embodiment, in step S1, the mechanical property parameters and thermophysical property parameters of the material include elastic modulus, Poisson's ratio, thermal expansion coefficient, thermal conductivity, specific heat capacity, density and yield strength.

[0065] In a specific embodiment, in step S2, the finite element mesh division of the geometric model is specifically as follows: gradual mesh division is performed based on the geometric model, a fine mesh size is used in the annular weld area and its vicinity, and a sparse mesh distribution is used in the area away from the welding layer, and the mesh size gradually increases.

[0066] In a specific embodiment, step S2 also includes an analysis step setting, which is as follows: every two steps of the entire welding process are set as a heat source heating step and a post-weld cooling step, the heat source heating step is started at the beginning of welding, and the post-weld cooling step is performed for a period of time after the welding is completed, and the welding of the next weld is repeated, and finally a cooling analysis step is performed after the welding is completed.

[0067] In a specific implementation, in step S2, the boundary condition setting includes thermal boundary condition setting and mechanical boundary condition setting.

[0068] In a specific implementation, the welding thermal boundary conditions are set as follows:

[0069] The initial temperature of the welding structure and the ambient temperature are both defined as 20°C;

[0070] Combine heat convection and heat radiation conditions into heat transfer boundaries;

[0071] The same heat transfer boundary conditions are set for all external surfaces of the model.

[0072] In a specific embodiment, the welding mechanical boundary conditions are set as follows: the translational degrees of freedom in the X, Y, and Z directions of the fixture area are constrained in the simulation model, and after the fixture constraints are released after welding, three-point constraints are applied to the overall structure.

[0073] In a specific implementation, in step S2, a welding heat source is applied based on a heat source subroutine to heat the weld, a Gaussian heat source model is adopted as the heat source model, and the calculation files include an ini heat source file, an ini trajectory file, an ini heat source and trajectory association file, a dll heat source compilation file, an inp model input file, an env environment file, and a bat batch processing file.

[0074] In a specific implementation, step S3 is as follows:

[0075] The initial values ​​of the heat source parameters are defined based on the weld size and empirical criteria. The initial calculation results of the temperature field are obtained after submitting the transient analysis solution. The molten pool morphology of the preliminary simulation results is compared with the actual welding molten pool size. The heat source parameters are continuously adjusted and iteratively calculated. Finally, a heat source model close to the actual molten pool shape is obtained by verification.

[0076] In a specific implementation, step S4 is as follows:

[0077] The thermo-elastic-plastic finite element method with thermal-mechanical sequential coupling is used to analyze and calculate the welding mechanical field. The obtained welding temperature field simulation results are imported into the network model to calculate the stress-strain field, and finally the welding residual stress and welding deformation are obtained.

[0078] In a second aspect, the present invention further provides an electronic device comprising:

[0079] processor;

[0080] Memory;

[0081] and a computer program, wherein the computer program is stored in the memory, the computer program comprising instructions, which, when executed by the processor, cause the electronic device to perform the simulation method.

[0082] In a third aspect, the present invention further provides a computer-readable storage medium, wherein the computer-readable storage medium includes a stored program, wherein when the program is executed, the device where the computer-readable storage medium is located is controlled to execute the simulation method.

[0083] Example 1

[0084] like Figure 1 As shown, the embodiment of the present invention provides a tube-to-sheet weld electron beam welding numerical simulation method based on ABAQUS, comprising the following steps:

[0085] S1, geometric model establishment and model input parameter acquisition

[0086] According to the actual size, the three-dimensional geometric model of the heat exchange tube and tube sheet is established in the ABAQUS-Part module through stretching, rotation, sweeping and other means. The millimeter system is used for modeling, such as Figure 2 As shown, there are 6 heat transfer tubes, the materials of the heat transfer tubes and tube sheets are both set to titanium alloy, there is a gap fit between the heat transfer tubes and the tube sheets, and they are welded in a specific welding sequence. After the welds are naturally cooled, the overall structure forms 6 annular welds. The material composition is input into the software JMatpro to calculate the material mechanical properties parameters and thermophysical properties parameters that change with temperature;

[0087] The elastic modulus, Poisson's ratio, thermal expansion coefficient, thermal conductivity, and specific heat capacity of titanium alloy materials change with temperature. The density is set as a constant. The plasticity parameters are set to include the yield strength under different temperatures and different plastic strains. The material yield behavior obeys the Von-Mises yield criterion and satisfies the plastic hardening criterion. In ABAQUS, material properties are assigned to the welded structure by establishing Material and Section.

[0088] S2, finite element modeling

[0089] Based on the geometric model of S1, finite element meshing is performed to discretize the geometric model into several simple-shaped mesh units, thereby obtaining a finite element mesh model. Meshing is performed to obtain a structural mesh model. Different mesh unit types are assigned according to the analysis result type, and the corresponding analysis type is set in the corresponding analysis step; by converting and setting material parameters, contact conditions, boundary condition parameters, and applying welding heat source at the weld, a finite element analysis model of the actual welding process is established;

[0090] In the process of mesh processing, a gradient mesh processing method is used, that is, a fine mesh size is used in the annular weld area and its vicinity, while a sparse mesh distribution is used in the area away from the welding layer. The mesh size gradually increases. The mesh model is as follows: Figure 3 As shown;

[0091] The meshes are all hexahedral units, the unit order is first order, and the mesh size ranges from 0.3 to 1.0 mm. In thermal analysis, DC3D8 units are used. Such unit nodes only contain temperature degrees of freedom, which are used to solve thermal properties such as temperature field distribution of each node at different times. In mechanical analysis, the same set of mesh division models is used, and the unit type is converted to C3D8R unit;

[0092] Analysis step setting: according to the distribution of weld bead planning, the entire welding process is set to 12 analysis steps. Every two steps include heat source heating step and post-weld cooling step, that is, the calculation and analysis of each weld includes 2 analysis steps. When welding starts, the heat source heating step is started. After welding, a period of post-weld cooling step is performed, followed by welding of the next weld bead. The last step is the cooling analysis step after welding. When performing thermal analysis, the analysis step type is Heat transfer. When performing mechanical analysis, the analysis step type is changed to Static General. The number of analysis steps and the time of each analysis step of thermal analysis and mechanical analysis must be consistent.

[0093] The welding thermal boundary conditions are set, and the initial temperature of the welding structure and the ambient temperature are both defined as 20°C. The outer surface of the tube sheet has a thermal convection boundary with the air, the inner wall of the pipe has a thermal convection boundary with the water, and there is also a thermal radiation boundary. The thermal convection and thermal radiation conditions are combined into a heat transfer boundary, and the same heat transfer boundary conditions are set for all the outer surfaces of the model;

[0094] The welding mechanical boundary conditions are set. During the welding process, the heat transfer tube and the tube sheet test piece are clamped on both sides of the tube sheet by a fixture. In the simulation model, the translational freedom of the region in the X, Y, and Z directions is constrained, thereby limiting the rigid body displacement of the entire workpiece. After the fixture constraint is released after welding, in order to avoid the calculation being unable to proceed due to rigid body displacement, three-point constraints are imposed on the overall structure, that is, one point on a plane constrains the translational freedom of X, Y, and Z, another point constrains the translational freedom of X and Z, and the last point constrains the translational freedom of Z. The three-point application positions are as follows: Figure 4 As shown;

[0095] Based on the heat source subroutine, welding heat source is applied to heat the weld. The heat source model adopts Gaussian heat source model. The calculation files include ini heat source file, ini trajectory file, ini heat source and trajectory association file, dll heat source compilation file, inp model input file, env environment file and bat batch processing file, such as Figure 5 As shown;

[0096] Among them, the ini heat source file defines the heat source type, heat source parameters (including heat source shape parameters, thermal efficiency) and welding process parameters; the ini trajectory file reflects the welding path based on the spatial coordinates of the grid nodes, and extracts the spatial normal vectors of each node to determine the distribution direction and position of the heat source; the ini heat source and trajectory association file is used for the association of the environment configuration file, background submission file, subroutine and inp file; the dll file is the file format compiled from the Fortran subroutine, which directly defines the non-uniform heat flow distribution conditions related to position, time and physical quantity. This file is associated with the ABAQUS version. The file reflects the input and effect of welding heat in the form of functions, which can be specifically expressed as different heat source types; the inp file is a simulation input file, which contains definitions such as grid nodes, analysis type and quantity, thermal boundary conditions, output variable type and frequency; the env file is an environment file, which defines the current file position in the file; the bat file is a batch file, which contains the inp file name and the definition of the number of cpu cores, and is used for the submission operation of the simulation calculation;

[0097] S3, temperature field calculation analysis and heat source verification

[0098] Based on the S2 finite element analysis model, the initial values ​​of the heat source parameters are defined based on the weld size and empirical criteria. After submitting the transient analysis solution in ABAQUS, the initial calculation results of the welding temperature field are obtained, and the temperature distribution at different times and positions is obtained. The molten pool morphology of the simulation results is compared with the actual welding molten pool size and temperature, and the welding heat source is calibrated. The heat source parameters are continuously adjusted for iterative calculations. Finally, a heat source model close to the actual molten pool shape is obtained, and a welding simulation result that is more in line with the actual situation is obtained. Figure 6 As shown;

[0099] S4, mechanical field calculation analysis

[0100] Based on the heat source model after S3 verification and the temperature field results calculated, the thermal-elastic-plastic finite element method with thermal-mechanical sequential coupling is used to continue the welding mechanical field analysis and calculation. The welding temperature field simulation results obtained during the welding process are imported into the grid model as the initial load for stress-strain field calculation. The stress field is obtained after changing the unit type. For the finite element model with the same grid model but different unit types, the temperature load is applied at the same node of the unit using the temperature field results, and the welding stress-strain distribution of the welded structure is obtained by continuing to solve, and then the welding residual stress and welding deformation distribution are obtained. After the calculation is completed, the simulation results of the stress field and deformation are viewed in the post-processing interface. The residual equivalent stress cloud diagram after welding is shown as follows: Figure 7 As shown;

[0101] S5, Welding Sequence Analysis

[0102] Based on the calculation process of S3 and S4, the temperature field and mechanical field are calculated for the simulation cases of different welding sequences in batches, the welding deformation under different welding sequences is calculated and analyzed, and the welding deformation field under different welding sequences is obtained. Finally, the optimal welding process parameters are selected according to the overall deformation amount; the welding sequence is as follows: Figure 8 As shown in the figure, the starting welding direction of each weld is counterclockwise in the same direction. The difference in welding sequence is reflected in the welding time of different annular welds. By applying welding heat source to the weld at different times, the welding deformation under different welding sequences is calculated and analyzed, and the welding sequence with the smallest overall deformation is selected.

[0103] Example 2

[0104] An embodiment of the present invention further provides an electronic device including:

[0105] processor;

[0106] Memory;

[0107] and a computer program, wherein the computer program is stored in the memory, the computer program comprising instructions, which, when executed by the processor, cause the electronic device to perform the simulation method.

[0108] Example 3

[0109] An embodiment of the present invention further provides a computer-readable storage medium, wherein the computer-readable storage medium includes a stored program, wherein when the program is executed, the device where the computer-readable storage medium is located is controlled to execute the simulation method.

[0110] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A numerical simulation method for electron beam welding of tube-to-sheet welds based on ABAQUS, characterized in that: The steps include: S1, establish a three-dimensional geometric model of the heat exchange tube and tube sheet in ABAQUS, input the material composition in the material performance simulation software, and calculate the material mechanical performance parameters and thermophysical performance parameters that vary with temperature; S2, based on the geometric model of S1, meshing is performed to obtain a structural mesh model. By converting and setting material parameters, contact conditions, boundary condition parameters, and applying welding heat source at the weld, a finite element model of the actual welding process is established; S3, based on the finite element model of S2, the welding temperature field is calculated in ABAQUS to obtain the welding simulation temperature distribution at different times and positions; S4, based on the temperature field results of S3, the sequential coupling method of thermal-mechanical coupling is used to calculate the welding stress-strain distribution of the welded structure, and then the welding residual stress and welding deformation distribution are obtained; S5, based on the calculation process of S3 and S4, applies welding heat source to the weld at different times, calculates and analyzes the welding deformation under different welding sequences, and obtains the welding process parameters according to the overall deformation amount.

2. The ABAQUS-based numerical simulation method for tube-to-sheet weld electron beam welding according to claim 1, characterized in that: In step S1, the mechanical property parameters and thermophysical property parameters of the material include elastic modulus, Poisson's ratio, thermal expansion coefficient, thermal conductivity, specific heat capacity, density and yield strength.

3. The method for numerical simulation of electron beam welding of tube-to-sheet weld based on ABAQUS according to claim 1, characterized in that: In step S2, the finite element mesh division of the geometric model is specifically as follows: gradual mesh division is performed based on the geometric model, a fine mesh size is used in the annular weld area and its vicinity, and a sparse mesh distribution is used in the area far away from the welding layer, and the mesh size gradually increases.

4. The method for numerical simulation of electron beam welding of tube-to-sheet weld based on ABAQUS according to claim 1, characterized in that: Step S2 also includes the analysis step setting, which is as follows: every two steps of the entire welding process are set as a heat source heating step and a post-weld cooling step, the heat source heating step is started at the beginning of welding, and the post-weld cooling step is performed for a period of time after the welding is completed, and the welding of the next weld is repeated, and finally the cooling analysis step is performed after the welding is completed.

5. The method for numerical simulation of electron beam welding of tube-to-sheet weld based on ABAQUS according to claim 1, characterized in that: In step S2, the boundary condition setting includes the thermal boundary condition setting and the mechanical boundary condition setting.

6. The ABAQUS-based numerical simulation method for tube-to-sheet weld electron beam welding according to claim 5, characterized in that: The welding thermal boundary conditions are set as follows: The initial temperature and ambient temperature of the welding structure are defined as the same temperature as the actual working environment; Combine heat convection and heat radiation conditions into heat transfer boundaries; The same heat transfer boundary conditions are set for all external surfaces of the model.

7. The method for numerical simulation of electron beam welding of tube-to-sheet welds based on ABAQUS according to claim 5, characterized in that: The welding mechanical boundary conditions are set as follows: in the simulation model, the corresponding translational degrees of freedom in the X, Y, and Z directions of the fixture area are constrained, and after the fixture constraints are released after welding, three-point constraints are applied to the overall structure.

8. The method for numerical simulation of electron beam welding of tube-to-sheet weld based on ABAQUS according to claim 1, characterized in that: In step S2, welding heat source is applied based on the heat source subroutine to heat the weld. The heat source model adopts Gaussian heat source model. The calculation files include ini heat source file, ini trajectory file, ini heat source and trajectory association file, dll heat source compilation file, inp model input file, env environment file and bat batch processing file.

9. The ABAQUS-based numerical simulation method for tube-to-sheet weld electron beam welding according to claim 8, characterized in that: Step S3 is as follows: The initial values ​​of the heat source parameters are defined based on the weld size and empirical criteria. The initial calculation results of the temperature field are obtained after submitting the transient analysis solution. The molten pool morphology of the preliminary simulation results is compared with the actual welding molten pool size. The heat source parameters are continuously adjusted and iteratively calculated. Finally, a heat source model close to the actual molten pool shape is obtained by verification.

10. The ABAQUS-based numerical simulation method for tube-to-sheet weld electron beam welding according to claim 8, characterized in that: Step S4 is specifically as follows: The thermo-elastic-plastic finite element method with thermal-mechanical sequential coupling is used to analyze and calculate the welding mechanical field. The obtained welding temperature field simulation results are imported into the network model to calculate the stress-strain field, and finally the welding residual stress and welding deformation are obtained.

11. An electronic device, characterized in that: include: processor; Memory; and a computer program, wherein the computer program is stored in the memory, and the computer program includes instructions, which, when executed by the processor, enable the electronic device to perform the method according to any one of claims 1 to 10.

12. A computer-readable storage medium, characterized in that: The computer-readable storage medium includes a stored program, wherein when the program is executed, the device where the computer-readable storage medium is located is controlled to execute the method according to any one of claims 1 to 10.

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