Welding simulation method and system based on sub-field modeling

Abstract

The invention relates to the field of welding technology and finite element analysis, and particularly discloses a welding simulation method and system based on sub-field modeling. According to the system, the welding area is divided into a plurality of sub-fields, so that the simulation precision and efficiency are improved. The system comprises four main parts: gridding, heat source setting, thermal analysis and structural analysis. And the gridding module realizes fine grid division of the complex geometry by utilizing a sub-field technology and combining isotherm information. The heat source setting module accurately defines heat input conditions in the sub-fields according to welding process requirements. The thermal analysis module simulates the change of a temperature field in the welding process and provides detailed sub-field temperature distribution data. And the structural analysis module analyzes stress and deformation caused by welding based on the thermal analysis result, and particularly focuses on stress transfer and deformation behaviors among the sub-fields. According to the whole system, the welding simulation precision is greatly improved, manual intervention is reduced, and powerful technical support is provided for optimization of a complex welding process.

Description

Technical Field

[0001] The invention relates to the field of welding technology and finite element analysis, and specifically discloses a welding simulation method and system based on sub-domain modeling. Background Art

[0002] With the continuous acceleration of the intelligentization and digitalization of the manufacturing industry, welding technology plays an increasingly important role in high-precision industries such as automobile manufacturing, aerospace, and shipbuilding. The quality of welding not only affects the structural integrity and durability of the product, but also the overall performance and service life. Therefore, the optimization of welding processes and the development of simulation technology have become hot areas of current research and application.

[0003] In welding simulation technology, finite element analysis has become a standard technical means to simulate heat conduction, stress and deformation in the welding process. However, existing welding simulation software still faces many challenges when dealing with complex welding scenarios. Especially in the simulation process, how to accurately capture the changes in temperature field and stress distribution during welding is a key factor affecting the simulation accuracy. At present, most simulation software uses simple heat source models and meshing methods, which cannot fully reflect the complex thermal-mechanical coupling effects in the welding process, thus affecting the accuracy of the simulation results.

[0004] As welding processes become increasingly complex and diverse, existing simulation software has shown certain limitations when dealing with high temperature gradients and nonlinear material properties. Especially when it comes to multi-layer and multi-pass welding processes, existing software often finds it difficult to accurately simulate temperature and stress fields. In addition, existing finite element analysis software often requires users to have high professional knowledge when dealing with complex geometries and multi-material welding, and the operation is cumbersome and prone to human errors.

[0005] In order to improve the accuracy and efficiency of welding simulation technology, there is an urgent need for a finite element welding simulation software that can perform accurate thermal and structural analysis based on sub-domain information. Through the precise division and analysis of sub-domains, the temperature distribution and stress changes in the welding process can be simulated more realistically, thereby optimizing the welding path and improving the reliability and operability of the simulation results. This can not only meet the current high requirements of the manufacturing industry for welding simulation software in the direction of intelligence and automation, but also provide a more scientific basis for the optimization design of welding processes. Summary of the invention

[0006] The present invention aims to significantly improve the accuracy and efficiency of welding simulation process through a welding simulation method and system based on sub-domain modeling. The system includes four main modules: gridding, setting welding parameters, thermal analysis and structural analysis. Through intelligent algorithms and advanced computing technology, the temperature field and stress distribution in the welding process can be accurately captured.

[0007] The core of this invention is to optimize the thermal and structural analysis processes in welding simulation by using sub-domain information. By accurately defining the heat source, the system can simulate the heat conduction process in welding more realistically and adjust the simulation parameters in real time to adapt to complex geometric shapes and multi-material welding processes. The meshing module greatly improves the efficiency of meshing while ensuring high accuracy and reduces the dependence on user expertise.

[0008] In addition, the software system solves the speed and accuracy bottlenecks encountered by existing technologies when dealing with complex welding scenarios by integrating intelligent algorithms and efficient simulation engines. Users can quickly obtain high-precision simulation results through the system, thereby optimizing welding process design, improving welding quality, and shortening production cycles. This invention not only improves the accuracy and response speed of welding simulation, but also provides strong technical support for the optimization of welding processes and the intelligent development of the manufacturing industry.

[0009] To achieve the above object, the present invention provides the following technical solution: a welding simulation method and system based on sub-domain modeling, the method comprising the following steps:

[0010] Step 1: Import entities

[0011] The user imports the geometry required for subsequent operations.

[0012] Step 2: Construct the surface

[0013] The user constructs the surface of the imported geometry one by one.

[0014] Step 3: Select the welding path

[0015] The user selects two adjacent geometric bodies or a single geometric body and welds the connecting parts.

[0016] Step 4: Solid Meshing

[0017] The user selects specific geometries and specifies the appropriate mesh type in turn, and the system will automatically perform mesh division based on the shape of the geometries and welding requirements.

[0018] Step 5: Merge weld entities

[0019] Users can use the weld entity merging function, and the system will intelligently and accurately merge the weld entity with the geometric body according to the preset welding path and process requirements.

[0020] Step 6: Setting the Heat Source

[0021] The user creates the heat source to be used in the weld joint.

[0022] Step 7: Setting the Solder Joints

[0023] The user sets the location of the weld joint and its heat source.

[0024] Step 8: Calculate duration

[0025] The system calculates the number of steps required in the welding process and divides the geometry into sub-domains.

[0026] Step 9: Thermal Analysis

[0027] The system performs thermal analysis of the geometry and weld during the welding process to simulate the temperature distribution and heat-affected zone.

[0028] Step 10: Displacement Analysis

[0029] The system performs displacement analysis on the geometry and weld during the welding process to evaluate the deformation and stress distribution caused by welding.

[0030] Step 11: Stress-Strain Analysis

[0031] The system performs stress-strain analysis on the geometry and welds during the welding process, and evaluates the mechanical responses including equivalent stress, equivalent plastic strain, plastic strain, and nodal stress to accurately predict the material strength and deformation behavior during the welding process.

[0032] Compared with the prior art, the present invention has the following advantages:

[0033] (1) The present invention integrates multiple functions such as geometry file processing, meshing, welding path planning and geometry merging. The system can automatically process multiple geometry file formats, intelligently generate high-precision meshes, and support flexible surface construction and mesh type selection. Through precise welding path planning and geometry fusion functions, the accuracy of the welding process and the integrity of the model are ensured, thereby simplifying the user operation process and improving the efficiency and accuracy of simulation and analysis.

[0034] (2) The present invention divides the complex welding area into multiple sub-fields by introducing sub-field modeling technology. Each sub-field can be finely modeled and analyzed independently. This method allows the system to finely simulate the local temperature changes, stress distribution and deformation behavior of different regions in the welding simulation. Through sub-field modeling, the system can effectively improve the simulation accuracy, reduce the consumption of computing resources, and provide more accurate welding parameter optimization suggestions.

[0035] (3) The thermal analysis function provided by the system allows users to set detailed heat transfer parameters, including constant performance, ambient temperature, convection coefficient, etc. Through these settings, the system can accurately simulate phenomena such as heat conduction, convection and radiation during welding. Thermal analysis can accurately predict the temperature field distribution in the welding area, identify the range and temperature gradient of the heat-affected zone, and provide accurate heat load conditions for subsequent structural analysis.

[0036] (4) The system has powerful structural analysis capabilities and can accurately simulate the stress and displacement that may occur during and after welding based on user-set parameters such as the number of iterations, temperature thresholds, and directional constraints. By analyzing the geometric deformation and stress concentration caused by thermal stress, the system can predict the plastic deformation, stress concentration areas, and residual stress that may occur during welding, thereby helping users prevent welding defects and improve welding quality and product durability.

[0037] (5) The system evaluates key indicators such as equivalent stress, equivalent plastic strain, plastic strain and node stress through stress-strain analysis in welding simulation. These analyses can provide users with detailed information on material strength and deformation behavior, which helps to optimize welding process parameters, reduce residual stress and improve the mechanical properties of welded joints.

[0038] (6) By adopting advanced sub-domain modeling, thermal analysis and structural analysis techniques, the present invention can optimize computing time and resource utilization while maintaining high-precision simulation. The system design allows users to be more flexible and precise in setting parameters, ensuring that the simulation results are both accurate and efficient, significantly improving the design and optimization capabilities of the welding process. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 Flow chart of this method. DETAILED DESCRIPTION

[0040] Although the present invention can be implemented in a variety of ways, the accompanying drawings and exemplary embodiments are only for the purpose of illustrating the present invention and do not limit its scope. These embodiments are intended to present the content of the present invention more comprehensively and help those skilled in the art understand the core concept of the invention. The structure, performance, effect or other features described in a specific embodiment can be flexibly combined with other embodiments, provided that it conforms to the technical concept of the present invention. Those skilled in the art can also make corresponding implementations according to the concept of the present invention without certain specific features.

[0041] As attached Figure 1 As shown, Figure 1 A flowchart of a welding simulation system based on sub-domain modeling and analysis is shown. The system can intelligently perform meshing, welding parameter setting, thermal analysis, and structural analysis to achieve efficient welding simulation and process optimization. This embodiment includes:

[0042] Users can import geometry files in ".stl", ".cdf" or ".k" format, and the system will automatically recognize and load these files to ensure their correct display and operation in the simulation environment. After importing, the system will convert the geometry from a meshed coordinate system to a meshless coordinate system to determine the calculation space area, providing a basis for meshing and welding path planning.

[0043] All imported geometry files will be uniformly converted to ".stl.cdf" format. The system automatically generates ".stl.cdf" files for ".stl" and ".k" format files; for ".cdf" format files, first de-mesh and then generate ".stl.cdf" files. Users can select geometry and specify material properties through a visual interface to ensure the accuracy of simulation parameters.

[0044] After selecting the geometry, the user selects the starting point, midpoint and end point of the welding path by clicking on the interface, and the system automatically records these coordinates. After the user sets the parameters such as weld material, margin tolerance, face distance tolerance, weld unit size, center size, number of arc units, number of weld layers, start offset and end offset, the system automatically generates the weld joint and the optimal welding path.

[0045] Users can select the appropriate mesh type for meshing according to the geometry type, and set the proximity tolerance and truncation coefficient. The system will automatically generate the solid model after welding according to the set parameters and welding path to ensure the accuracy and quality of the welding results.

[0046] Next, the user needs to set the heat source parameters of the welding joint, including welding speed, voltage, current, thermal efficiency and heating radius, etc., to accurately control the welding heat input and temperature distribution.

[0047] Users also need to set other parameters of the weld joint, including welding path, number of sub-weld passes, dwell time, start and end point ratio, as well as tack welds and global welds to accurately determine the weld pass layout and welding sequence of the weld joint.

[0048] Before performing thermal and structural analysis, users need to set parameters such as the interval time, cooling time, exponential coefficient, number of joint elements, number of subdomain elements, and subdomain thickness of the welding process to calculate the number of steps in the welding process and divide the geometry and welds into multiple subdomains.

[0049] When performing thermal analysis, users need to set the following key parameters: constant performance, whether to enable the solver, ambient temperature, convection coefficient, simulation start step number, end step number, and VTK output step size. These parameters determine the accurate simulation of heat transfer mechanisms such as heat conduction, convection, and radiation during the welding process. Based on these parameters set by the user, the system will perform a detailed thermal analysis of the temperature field during the welding process, predict the temperature distribution in the welding area and the heat-affected zone, and thus provide accurate initial conditions for subsequent structural analysis.

[0050] When performing displacement analysis, users need to set the following parameters: number of iterations, plastic update options, temperature threshold, constraint point location, directional constraints, simulation start steps, end steps, and VTK output step size. These parameters are used to accurately simulate the displacement and deformation behavior of the geometry and welds during the welding process. Through these settings, the system can effectively analyze the displacement changes of the geometry and welds caused by thermal stress during the welding process, and evaluate the amount and direction of deformation that may occur during the welding process.

[0051] When performing stress-strain analysis, users need to configure the following key parameters: ambient temperature, post-processing flag, simulation start step number, end step number, and VTK output step size. These parameters will guide the system to automatically perform detailed stress-strain analysis on the geometry and welds, including calculating equivalent stress, equivalent plastic strain, plastic strain, and node stress. Through these analyses, the system can accurately evaluate the strength and deformation behavior of the material during the welding process and predict the residual stress and plastic deformation areas that may be generated.

Claims

1. A welding simulation method and system based on sub-domain modeling has the following characteristics: the user first imports the geometry file and constructs the surface of the geometry to prepare for the subsequent welding path selection and solid meshing operations. Then, through the weld entity merging function, the meshed geometry is merged with the weld to generate a new solid model. The user also needs to set the heat source parameters of the weld joint and enter the preset system parameters to determine the welding configuration of the weld. Before performing thermal analysis and structural analysis, the system will calculate the time and number of steps required in the welding process. Finally, after the user enters all the necessary parameters, the system will automatically perform thermal analysis and structural analysis to optimize the welding process and results.

2. The method according to claim 1, characterized in that: Geometry import supports files with suffixes of ".stl", ".cdf" or ".k", and allows multiple geometries to be imported at the same time. After import, the geometry will be presented in VTK format and CDF format, of which VTK format supports 3D display. When constructing a surface, the user needs to select the geometry and its material, select the superstructure, substructure, start point, midpoint, and end point by clicking on the visual interface, and set parameters such as margin tolerance, face distance tolerance, and unit size. After completing the path selection, the system automatically generates the weld.

3. The method according to claim 1, characterized in that: Solid meshing requires the user to select the geometry and the corresponding mesh type, and set the relevant parameters. The supported mesh types include PQSurface, GeneralSheetMetal, etc. 10 types. The weld entity merging function requires the user to input the proximity error and truncation coefficient. The system will automatically generate the welded solid model based on these parameters, welding path and meshed entities.

4. The method according to claim 1, characterized in that: When setting welding parameters, users first need to define the heat source parameters of the weld joint, including welding speed, voltage, current, thermal efficiency and heating radius. Next, users set the welding path and related parameters for each weld joint, such as the number of welds, the number of sub-welds, the dwell time, the starting point ratio, the end point ratio, the positioning weld and the global weld point to determine the specific weld configuration. Finally, users select a pre-defined heat source to complete the setting of welding parameters.

5. The method according to claim 1, characterized in that: When calculating the duration, the user needs to set parameters such as the interval time, cooling time, exponential coefficient, number of joint units, number of subdomain units, and subdomain thickness. The system will calculate the number of steps required in the welding process based on these parameters, and divide the geometry and welds into multiple subdomains to achieve more sophisticated local modeling and analysis, and improve simulation accuracy and calculation efficiency.

6. The method according to claim 1, characterized in that: The user needs to set a series of parameters, including constant performance, whether to enable the solver, ambient temperature, convection coefficient, simulation start step number, end step number, and VTK output step size. By accurately setting these parameters, the system can simulate heat transfer phenomena such as heat conduction, convection, and radiation during welding. The results of thermal analysis will predict the temperature distribution in the welding area, determine the range and temperature gradient of the heat-affected zone, and thus provide a reliable data basis for subsequent structural analysis.

7. The method according to claim 1, characterized in that: The user needs a series of parameters, including the number of iterations, plastic update options, temperature thresholds, the location of the constraint points, directional constraints, the number of simulation start steps, the number of end steps, and the VTK output step size. These settings will help the system accurately analyze the displacement of the geometry and welds during the welding process. Displacement analysis evaluates the response of the geometry and welds under different temperature and stress states by examining the deformation caused by thermal stress and thermal expansion during the welding process.

8. The method according to claim 1, characterized in that: Users need to configure a series of parameters, including ambient temperature, post-processing flag, simulation start step number, end step number, and VTK output step size. These parameters will guide the system to automatically perform stress-strain analysis of the geometry and welds during the welding process. The analysis process includes the calculation of equivalent stress, equivalent plastic strain, plastic strain and node stress, aiming to evaluate the material strength and deformation behavior of the welding area. Through detailed stress-strain analysis, the system can accurately predict the stress concentration, plastic deformation and residual stress that may occur during and after welding.

9. The method according to claim 1, characterized in that: The system provides a visualization function for welding results. After the simulation is completed, users can view the three-dimensional visualization results of the temperature field, stress field and displacement field of the geometry and weld during the welding process. The visualization results include color maps, contour maps and animation displays. Users can observe the heat distribution, stress concentration and deformation in detail during the welding process through operations such as rotation, zooming and translation. This visualization function helps users intuitively understand the welding simulation results and assists in welding process optimization and quality assessment.

10. The method according to claim 1, characterized in that: The system includes automated post-processing capabilities. Users can set key parameters such as stress thresholds, strain limits, and upper temperature limits, and the system will automatically post-process and analyze the results after the simulation is completed. Automated post-processing capabilities include generating stress-strain curves, temperature distribution maps, and residual stress fields, as well as automatically identifying and reporting possible weld defect areas.

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