A welding simulation method and system for a frame welding sub-assembly

Abstract

The application relates to the technical field of vehicles and provides a welding simulation method and system for a frame welding sub-assembly; the method comprises the following steps: S1: based on a welding process of the frame welding sub-assembly, all supply level parts and welding manufacturing features are identified; S2: a three-dimensional model of each supply level part is pretreated or simplified, input into simulation software, and a weld three-dimensional model associated with the supply level part model is constructed or input based on the welding manufacturing features, so that a 1:1 global three-dimensional model is assembled; meanwhile, a local joint model associated with the global three-dimensional model is constructed; S3: based on the global and local two-level three-dimensional models, a first preset strategy is simulated to obtain welding deformation and stress risk zones of the frame welding sub-assembly; and S4: based on the welding deformation and stress risk zones, a second preset strategy is simulated to obtain a target process design scheme of the frame welding sub-assembly. The application can improve the trial production efficiency of the existing frame sub-assembly and reduce the material and labor cost input.

Description

Technical Field

[0001] This application relates to the field of vehicle technology, and in particular to a welding simulation method and system for a chassis welding sub-assembly. Background Technology

[0002] The automotive frame is a crucial component that supports the body, powertrain, and running gear, playing a vital role in transmitting loads, absorbing shocks, and ensuring overall vehicle rigidity. Welding, as a primary joining process in frame manufacturing, directly impacts the frame's strength, fatigue life, and dimensional accuracy. In automated production lines, improperly controlled welding thermal deformation can lead to the following problems:

[0003] 1. Welding and assembly difficulties: Excessive deformation can prevent parts from being assembled smoothly, requiring manual correction, which increases labor time and costs;

[0004] 2. Welding stress concentration: Uneven distribution of residual stress can easily lead to fatigue cracks and reduce the service life of the frame;

[0005] Therefore, effectively controlling welding deformation of the chassis assembly and ensuring uniform distribution of residual stress after welding has become a crucial hurdle for enterprises to enhance their core manufacturing competitiveness. Current technologies often involve multiple rounds of physical process verification during the prototype manufacturing of chassis parts, providing solutions for part correction and fixture clamping. However, this approach suffers from drawbacks such as high costs associated with prototype verification, numerous verification rounds, and long quality development cycles. Summary of the Invention

[0006] The purpose of this invention is to provide a welding simulation method and system for chassis welding sub-assemblies. This method can identify and resolve prominent problems in welding process design in advance, propose optimization suggestions for welding process design, improve the trial production efficiency of existing chassis sub-assemblies, and reduce material and labor costs. The specific solution is as follows:

[0007] A welding simulation method for a vehicle frame welding sub-assembly, the method comprising the following steps:

[0008] S1: Based on the welding process of the chassis welding sub-assembly, identify all supply-level parts and welding manufacturing characteristics;

[0009] S2: Preprocess or simplify the 3D model of each supply-grade component, input it into the simulation software, and construct or input a weld 3D model associated with the supply-grade component model based on welding manufacturing features, assemble it into a 1:1 global 3D model; at the same time, construct a local joint model associated with the global 3D model;

[0010] S3: Based on the global and local two-level three-dimensional models, the first preset strategy is used for simulation to obtain the welding deformation and stress risk area of ​​the frame welding sub-assembly;

[0011] S4: Based on the welding deformation and stress risk zone, a second preset strategy is used for simulation to obtain the target process design scheme for the frame welding sub-assembly.

[0012] Optionally, in step S3, simulation is performed based on the global and local two-level 3D models using the first preset strategy to obtain the welding deformation and welding stress risk areas of the frame welding sub-assemblies, specifically including:

[0013] S301: Evaluate key components of the global welded sub-assembly model and construct local models (including user-defined models) for these key components. Preset the feature dimensions, material properties, mechanical and temperature boundaries, heat input, heat source model and parameters of the local models, and preset the mesh generation parameters for the local models. Start a finite element calculation program based on the thermo-elastoplastic principle to obtain the first simulation data for the key components. The first simulation data includes at least: temperature field and strain field results for the key components;

[0014] S302: Based on the global welding sub-assembly model, a simplified welding assembly fixture model, material properties, and welding sequence of the welding sub-assemblies are preset (input or created). The meshing parameters of the global model are also preset. The strain field results from the first simulation data are mapped to the global model. A finite element calculation program based on the inherent strain principle is then started to obtain the second simulation data of the global model. The second simulation data includes at least: stress-strain field results from the global model.

[0015] Optionally, the local simulation in step S301 uses finite element simulation technology that sequentially couples temperature field and stress field for key parts, and the mesh size ratio between the global three-dimensional model and the refined model is configured to be ≥ preset ratio, which facilitates smooth adaptation of the accuracy of the meshes of the two-level models.

[0016] Optionally, the local simulation in step S302 employs a finite element simulation technique that sequentially couples the temperature field and stress field for key components, specifically including:

[0017] The local simulation includes the welding heating stage and the post-weld cooling stage;

[0018] If the highest temperature during the welding heating stage is less than the solidus temperature threshold or greater than the preset ratio of the liquidus temperature threshold, the configuration parameters of the heat source model will be adjusted.

[0019] If the temperature of the critical parts is higher than the ambient temperature when the local simulation ends, the system parameters that take the longest time to solve should be allowed to cool down completely.

[0020] If the temperature field calculation is completed and the above conditions are met, the melting depth and melting width parameters of the molten pool are measured and statistically analyzed in the time domain above the solidus temperature of the simulated base material. The results are compared with the design target value. If the results are greater than or equal to the design target value, the strain field results are smoothed and output as the first simulation data.

[0021] Optionally, in step S302, the global three-dimensional model of the frame welding sub-assembly, which is used for global simulation, is split into a multi-process joint welding and assembly model corresponding to the actual production process.

[0022] In the simulation performed in steps S301 to S302, relevant attributes are predefined. The relevant attributes include at least: material properties, heat input, heat source model configuration, mechanical boundary, temperature boundary, welding assembly process and welding path. In step S302, the predefined relevant attributes are pre-configured based on the production process layout, and a clamping point model is constructed in this step.

[0023] Optionally, in step S4, a second preset strategy is adopted based on welding deformation and welding stress risk areas to obtain the target process design scheme for the frame welding sub-assembly, specifically including:

[0024] S401: Based on the second simulation data of the frame welding sub-assembly, the key welding risk areas are identified in accordance with the design requirements, namely the welding deformation and welding stress risk areas;

[0025] S402: Optimize process data based on the distribution characteristics of the risk area; the distribution characteristics include at least the location, shape, and corresponding fixture clamping point arrangement of deformation and stress risks.

[0026] S403: Input the optimized process data into the global 3D model, preset the mesh generation parameters, and then perform local-global simulation iterations using the thermo-elastic-plastic method and the inherent strain method until the peak values ​​of deformation and stress risk zones are all less than the set thresholds, and output the target process data; the target process data includes at least: welding heat input, welding path and fixture clamping point model.

[0027] A welding simulation system for a vehicle frame welding sub-assembly, the system comprising:

[0028] The modeling (or model building) module is configured to build a 3D weld model associated with the frame welding sub-assembly and its supply-level sub-components, build a simplified 3D model of the frame welding sub-assembly fixture, and build local 3D models of key parts of the frame welding sub-assembly and their corresponding mechanical boundaries.

[0029] The assembly (or model assembly) module is configured to identify and preprocess (or simplify) the 3D models of all supply-level components based on the chassis welding sub-assembly structure and welding process. Then, the preprocessed component models and weld models are input into the simulation software to complete the process-level assembly. At the same time, the simplified model of the welding sub-assembly fixture is input into the simulation software to form a virtual welding and assembly model.

[0030] The first processing module is configured as a local 3D model and a global welding assembly model of key parts of the frame welding sub-assembly. It adopts a first preset strategy to obtain the risk areas (welding deformation and welding stress) of the welding sub-assembly.

[0031] The second processing module is configured to identify the risk zone (welding deformation and welding stress) based on the global three-dimensional model and adopt the second preset strategy to obtain the target process design scheme (parameters) for the frame welding sub-assembly.

[0032] A simulation platform, comprising:

[0033] An electronic device for implementing the steps of the method according to claims 1-6;

[0034] A processor that runs a program, and when the program runs, it executes the steps of the method from data output by the electronic device.

[0035] A storage medium for storing a program that, when run, executes the steps of the method on data output from an electronic device.

[0036] This application adopts a modular, hierarchical simulation design layout. First, a two-level simulation strategy is used to identify welding deformation and stress risk zones through a global model of the welding sub-assemblies and welds, and related local key models. Second, a precise preset strategy is applied within the "local-global" two-level models to simulate and derive the optimized process design scheme (parameters). Through this method, the following beneficial technical effects are achieved:

[0037] (1) Improved the predictive capability of welding process design from a technical perspective.

[0038] This application provides a welding simulation method and system for a vehicle frame welding sub-assembly, which can identify and solve prominent problems in welding deformation control in the welding process design of the vehicle frame welding sub-assembly, and propose optimization suggestions for the welding process design scheme in advance.

[0039] Specifically, the simulation method and system for welding sub-assemblies of the vehicle frame provided in this application predicts the welding deformation trend and amount of the sub-assembly (including the evolution and concentration area of ​​welding stress) through process planning and design based on human experience and the linkage of "global-local" two-level simulation system modules, and provides product design improvement suggestions and welding process optimization suggestions in advance.

[0040] Meanwhile, the implementation of adaptive mesh generation technology in the system's basic layer can increase mesh density in critical areas (such as fusion zones and stress concentration zones) and improve mesh generation efficiency in general areas (such as areas far from welds), achieving a technical balance of "local fineness + global efficiency".

[0041] (2) Improved the ability to control process manufacturing risks from a quality perspective.

[0042] The welding simulation method and system provided in this application can simulate the welding deformation and stress distribution of the frame welding sub-assemblies based on product design requirements, thereby improving the pertinence and proactivity of controlling manufacturing risks in the process.

[0043] (3) It reduces trial production costs and resource consumption from an economic perspective.

[0044] The welding simulation method and system provided in this application can replace some physical materials with "digital products" and "digital solder", thereby reducing trial production and direct labor costs; by optimizing welding process parameters (such as reducing heat input), energy consumption is reduced, thus having certain technical and economic benefits. Attached Figure Description

[0045] Figure 1 This is a flowchart illustrating a welding simulation method for a vehicle frame welding sub-assembly.

[0046] Figure 2 This is a welding process flow diagram of the frame welding sub-assembly in one embodiment;

[0047] Figure 3 A schematic diagram showing the positional arrangement of the clamping point model on the vehicle welding sub-assembly;

[0048] Figure 4a and 4b Displacement field distribution diagram obtained by applying the welding simulation method of the chassis welding sub-assembly to the chassis welding sub-assembly. Detailed Implementation

[0049] To make the purpose, technical solution, and advantages of this application clearer, the following will be described in conjunction with the appendix. Figures 1-4a Section 4b provides a further detailed description of this application. It is obvious that the described embodiments are merely some, not all, of the embodiments described in this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0050] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to limit the application. The singular forms “a,” “said,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms, and “multiple” generally includes at least two unless the context clearly indicates otherwise.

[0051] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0052] It should be understood that although the terms first, second, third, etc., may be used in the embodiments of this application, these descriptions should not be limited to these terms. These terms are only used to distinguish the descriptions. For example, first may also be referred to as second without departing from the scope of the embodiments of this application, and similarly, second may also be referred to as first.

[0053] Depending on the context, the words “if” or “suppose” as used here can be interpreted as “when” or “in response to determination” or “in response to detection.” Similarly, depending on the context, the phrases “if determination” or “if detection (of the stated condition or event)” can be interpreted as “when determination” or “in response to determination” or “when detection (of the stated condition or event)” or “in response to detection (of the stated condition or event).”

[0054] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or device that includes said element.

[0055] It should be noted that any symbols and / or numbers present in the specification that are not marked in the accompanying drawings are not reference numerals.

[0056] The optional embodiments of this application are described in detail below with reference to the accompanying drawings.

[0057] Figure 1 The method shown is a welding simulation method for a vehicle frame welding sub-assembly, the method comprising the following steps:

[0058] S1: Based on the welding process of the chassis welding sub-assembly, identify all supply-level parts and welding manufacturing characteristics;

[0059] S2: Preprocess or simplify the 3D model of each supply-level part, input it into the simulation software, and build or input the weld 3D model associated with the supply-level part model to assemble it into a global 3D model; at the same time, build the local joint model associated with the global 3D model.

[0060] S3: Based on the global and local two-level three-dimensional models, the first preset strategy is used for simulation to obtain the welding deformation and stress risk area of ​​the frame welding sub-assembly;

[0061] S4: Based on the welding deformation and stress risk area of ​​the frame welding sub-assembly, the second preset strategy is used for simulation to obtain the target process design scheme of the frame welding sub-assembly.

[0062] Specifically, this application adopts an experience-based product process design (identifying supply-level components and welding manufacturing characteristics) and a modular hierarchical simulation design layout. First, through a two-level simulation strategy of global model of welding sub-assemblies and welds and related local key models, welding deformation and welding stress risk areas are identified. Then, through the "local-global" two-level model, a precise preset strategy is used to simulate and obtain the optimized process design scheme (parameters).

[0063] Alternatively, the modeling module and assembly module can construct a global model of the supply-level parts and welds, as well as local models of key parts associated with the global model; the first processing module can quickly locate the welding deformation and welding stress risk areas by applying a first preset strategy, and the second processing module can use a precise strategy to obtain an optimized target process design scheme (parameters).

[0064] The welding simulation method and system provided in this application can improve the predictive ability of welding process design, enhance the ability to control process manufacturing risks, and reduce trial production costs and manufacturing resource consumption.

[0065] In one specific embodiment, step S3 involves using a first preset strategy to simulate based on a global and local two-level three-dimensional model to obtain the welding deformation and welding stress risk areas of the frame welding sub-assemblies, specifically including:

[0066] S301: Evaluate key components of the global model of the welded subassembly and construct local models (including user-defined models) for these key components. Preset the feature dimensions, material properties, mechanical and temperature boundaries, heat input, heat source model and parameters of the local models, and preset the mesh generation parameters for the local models. Start a finite element calculation program based on the thermo-elastoplastic principle to obtain the first simulation data for the key components. The first simulation data includes at least: temperature field and strain field results for the key components;

[0067] S302: Based on the global welding sub-assembly model, a simplified welding assembly fixture model, material properties, and welding sequence of the welding sub-assemblies are preset (input or created). The meshing parameters of the global model are also preset. The strain field results from the first simulation data are mapped to the global model. A finite element calculation program based on the inherent strain principle is then started to obtain the second simulation data of the global model. The second simulation data includes at least: stress-strain field results from the global model.

[0068] Specifically, this embodiment adopts a layered and progressive simulation strategy of "global initial screening - local fine calculation - global detailed calculation". First, based on the welding and assembly process of the chassis welding sub-assembly, a global model of the sub-assembly and local models of key parts are constructed (global initial screening). The temperature field and smoothed and optimized strain field results of key parts are obtained through local simulation using the thermo-elastic-plastic method (local fine calculation). The strain field results are then input into the global model and quickly simulated using the inherent strain method to identify welding deformation and stress risk areas (global detailed calculation).

[0069] In one specific embodiment, the local simulation in step S301 employs a finite element simulation technique that sequentially couples temperature and stress fields for key components, and the mesh size ratio between the global 3D model and the local fine model is configured to be ≥ a preset ratio (e.g., ≥ 10). The advantage of this design is that the mesh for key components is sufficiently fine, while the computational efficiency for non-critical areas is significantly improved, effectively balancing simulation accuracy and computational efficiency, and providing sufficiently accurate data for the subsequent precise simulation of the global model.

[0070] In one specific embodiment, the local simulation in step S301 employs a finite element simulation technique that sequentially couples temperature and stress fields for key components, specifically including:

[0071] The local simulation includes the welding heating stage and the post-weld cooling stage;

[0072] If the highest temperature during the welding heating stage is less than the solidus temperature threshold or greater than the preset ratio of the liquidus temperature threshold, the configuration parameters of the heat source model will be adjusted.

[0073] If the temperature of the critical parts is higher than the ambient temperature when the local simulation ends, the system parameters that take the longest time to solve should be allowed to cool down completely.

[0074] If the temperature field calculation is completed and the above conditions are met, the melting depth and melting width parameters of the molten pool are measured and statistically analyzed in the time domain above the solidus temperature of the simulated base material. The results are compared with the design target value. If the results are greater than or equal to the design target value, the strain field results are smoothed and output as the first simulation data.

[0075] In one specific embodiment, the global three-dimensional model of the frame welding sub-assembly, which is simulated globally in step S302, is split into a multi-process joint welding and assembly model corresponding to the actual production process.

[0076] In the simulation performed in steps S301 to S302, relevant attributes are predefined. The relevant attributes include at least: material properties, heat input, heat source model configuration, mechanical boundary, temperature boundary, simulated assembly of welding assembly, and welding path. In step S302, the predefined relevant attributes are pre-configured based on the distribution of production processes, and a clamping point arrangement model is constructed in this step.

[0077] It is understood that this application accurately simulates the complete thermal cycle process of welding heating and post-weld cooling of key parts through finite element simulation technology that sequentially couples temperature field and stress field. At the same time, during the simulation process, strict verification rules are set for temperature peak, simulation termination temperature, and molten pool morphology parameters to promote the simulation results of local models to conform to actual welding conditions.

[0078] See Figure 4a and 4b Step S4: Based on the welding stress risk zone, a second preset strategy is adopted to obtain the target process parameters for the frame welding sub-assembly, specifically including:

[0079] S401: Based on the second simulation data of the frame welding sub-assembly, the key welding risk areas are identified in accordance with the design requirements, namely the welding deformation and welding stress risk areas;

[0080] S402: Optimize process data based on the distribution characteristics of the risk area; the distribution characteristics include at least the location, shape, and corresponding fixture clamping point arrangement of deformation and stress risks.

[0081] S403: Input the optimized process data into the global 3D model, preset the mesh generation parameters, and then perform local-global simulation iterations using the thermo-elastic-plastic method and the inherent strain method until the peak values ​​of deformation and stress risk zones are all less than the set thresholds, and output the target process data; the target process data includes at least: welding heat input, welding path and fixture clamping point model.

[0082] Specifically, in this embodiment, welding deformation and welding stress risk areas are determined based on the second simulation data. Then, the process parameters are optimized in a targeted manner according to the location, shape, and distribution characteristics of the risk areas and corresponding tooling processes, avoiding blind trial and error in the physical process. At the same time, the inherent strain method is used to verify the global simulation multiple times until the deformation and stress peak values ​​meet the design threshold requirements, thereby ensuring the rigor and feasibility of the target process data. It can also efficiently guide the welding process optimization of the frame welding sub-assemblies, accelerate the quality development of the welded frame sub-assemblies, and reduce the material and labor input in the physical part trial production process.

[0083] By adjusting the preset strategy of the local model of key parts, simulation is performed to obtain optimized (smoothed) strain field data, and the strain field data is mapped to the global model for simulation again. This avoids the problem of large computational costs of direct high-precision global model simulation, improves the accuracy of global 3D model simulation, achieves the unity of computational efficiency and simulation accuracy, and ensures the reliability of stress risk zone identification results.

[0084] For example, after adjusting the welding sequence and adding clamping points, the recalculation yielded the following:

[0085] The overall deformation of the frame welding sub-assembly (fourth crossbeam assembly) was reduced to less than 0.5mm, and the peak stress at the joint was reduced to about 340 MPa, which is below the stress threshold and fully meets the design requirements.

[0086] Once the risks have been confirmed to have been mitigated, the final process plan is then developed for physical prototype production.

[0087] In summary, this application uses finite element simulation technology to establish a 1:1 digital 3D model to simulate the welding thermal cycle process, thermo-elastic-plastic response, and product structural deformation. This allows for the prediction of welding process deformation before (trial) production, optimization of process parameters and product structural design, reduction of chassis trial production times, and shortening of product manufacturing development cycle.

[0088] It should be further noted that in recent years, with the development of multiphysics coupling algorithms and the improvement of computing power, welding finite element simulation is gradually shifting from "assisting manufacturing verification" to "assisting optimization design". The component structure and assembly scheme of the frame welding sub-assembly proposed in this invention aims to improve the dimensional accuracy of the components. By adopting finite element simulation technology, a welding simulation scheme for the frame welding sub-assembly is proposed (including the construction of heat source models and parameter adaptation technology) and measures for the customization and refinement of the simulation system interface, thereby accelerating the quality development of the welded frame sub-assembly and reducing material costs and labor input.

[0089] The following description uses the component structure and assembly process of the fourth crossbeam welding sub-assembly of the chassis as an example.

[0090] The fourth crossbeam welding subassembly of the chassis consists of eight types of supplier-grade components and is divided into two assembly and welding processes. (See reference...) Figure 2 .

[0091] This solution aims to identify and control welding deformation of the chassis welding sub-assemblies in advance. It constructs a "global-local-global-local-global" modeling analysis and simulation optimization workflow, and proposes a customized solution based on the achievement of product design goals. The concept is as follows:

[0092] 1. A two-level modeling strategy of "global-local" is adopted, which combines the finite element model of joint (i.e., local)-assembly (i.e. global) with solid mesh economic subdivision and accuracy matching technology to achieve the unity of welding simulation accuracy and efficiency of assembly.

[0093] 2. Based on the existing welding and assembly process schemes of the chassis welding assembly, identify the supplier-level components, simplify their models (e.g., the front plate of the fourth crossbeam) and weld models, convert them into standard entity data format, import them into the simulation system environment, and construct a global welding assembly simplified model of the chassis fourth crossbeam welding sub-assembly.

[0094] 3. Finite element simulation analysis technology that sequentially couples temperature and stress fields (i.e., the thermo-elastoplastic method) is applied to improve the realism of the simulated thermal cycle of the welding joint. The key locations mentioned above indicate the locations where important joints exist;

[0095] 4. Based on the process design requirements, construct a quick-reusable fixture clamping point model, and decompose the welding assembly and weld solid model into a multi-process combined welding and assembly model. After mapping the joint strain field results on the assembly and weld model, use the inherent strain method to quickly obtain the welding deformation trend and welding stress distribution law of the welding assembly, control welding deformation, and avoid post-weld stress concentration.

[0096] 5. Further propose optimization schemes for the simulation system interface (such as a simulation navigation tree table) to improve the efficiency or convenience of simulation operations.

[0097] Global modeling: Based on the 1:1 scale 3D design model of the fourth crossbeam welding sub-assembly, identify the list of supply-level components according to the process planning documents.

[0098] The supply-level component models (such as the front plate of the fourth crossbeam) are converted into standard data formats (such as STP) and imported into the simulation system environment.

[0099] For welded subassemblies at the supply level (such as the fourth crossbeam bracket 2 assembly), the welding heat effect of the projection weld nut is not considered, and the digital models of the projection weld nut and the sheet metal parts are merged.

[0100] For linear weld models, the model can be created in the simulation system environment, and the weld leg, weld deposition plane, and weld guide line can be set.

[0101] For curved weld models, they can be constructed in the CAD design environment through operations such as filling, surface extraction, surface combination, and segmentation, based on the design model. Alternatively, they can be imported into the simulation environment with a single click, based on a matrix relationship table composed of global coordinates of several points on the weld centerline.

[0102] Local modeling of joints

[0103] Based on the 1:1 3D model of the fourth crossbeam welding sub-assembly, the joint types (such as lap joints and T-joints) are identified according to the sheet metal thickness and grade, forming a list and joint model library. The lap length of lap joints and the inter-plate angle of T-joints are important attributes for classifying joint specifications.

[0104] Mesh generation and accuracy adaptation

[0105] The overall 3D model of the assembly, the clamping point model of the fixture, and the local models of key parts (such as joints) all use four-node tetrahedral meshes, and the meshing can be achieved with one-click adaptive meshing. Preferably, economical meshing parameters are given based on the number of mesh elements and the meshing time curve.

[0106] For example, the mesh size of the global 3D model of the assembly is 25-50mm, and the model accuracy (1.00E-4) and other parameter settings are the default values ​​of the system.

[0107] The mesh size of the joint local model is 1-10mm, and the model accuracy and other parameters are set to the system's default values. Preferably, the minimum mesh size is preset to 1 / 4-1 / 2 of the plate thickness, depending on the thickness of the joint base material.

[0108] The mesh size adaptation ratio of the global 3D model of the assembly and the joint model is designed to be at least greater than 10:1.

[0109] In the global-local-global simulation process, relevant attributes are predefined; the relevant attributes include at least: material properties, heat input, heat source model configuration, mechanical boundary, temperature boundary, and welding path;

[0110] Specifically:

[0111] Adding materials: Material properties need to be added to both the global 3D model of the assembly and the local model of the joint, including the material properties of the sheet metal parts, welds and fixtures.

[0112] The system's built-in material library is available for adding materials to sheet metal parts. This library includes the materials' thermal properties, such as specific heat capacity, density, and thermal conductivity, and how these properties change with temperature. If the system's material library does not contain the sheet metal or welding wire material the user needs, it is necessary to search for and supplement the material's thermal properties.

[0113] Define the heat input: The welding process for the fourth crossbeam welding sub-assembly of the welding frame is gas shielded arc welding. In the joint module of the simulation system, input parameters such as current (e.g., 160-260A), voltage (e.g., 17-24V), and thermal efficiency (e.g., 0.6-0.8).

[0114] Heat source model settings: In the system joint module, the heat source model of the welded joint can be set as a double ellipsoidal heat source model.

[0115] The main parameters of the double ellipsoidal heat source model are: front radius af (length of the front half ellipsoid axis), back radius ar (length of the back half ellipsoid axis), heat source radius (1 / 2 molten pool width) R and heat source height (molten pool depth) H, front half ellipsoid energy distribution coefficient fc, back half ellipsoid energy distribution coefficient bc, and heat flux concentration σ.

[0116] Ellipsoidal heat source models, Gaussian volumetric heat source models, hemispherical heat source models, cylindrical heat source models, or conical heat source models can all be used as alternatives. In applications such as multi-layer and multi-pass welding, multiple heat source models can be combined.

[0117] Define temperature boundaries: Before simulating the welded joint, consider temperature boundary conditions such as natural convection and thermal radiation between the workpiece and the environment to improve the accuracy of the temperature field. Preferably, a list of temperature boundary conditions is set according to the customer's application scenario to record the temperature boundary parameters for different application scenarios, such as the values ​​of key parameters like surface emissivity and convective heat transfer coefficient.

[0118] Defining the mechanical boundary: In the system joint module, the mechanical boundary is defined as the free end face of the plate. In the system structural component module, the mechanical boundary is the clamping points of the fixture (constraints in the x, y, z directions of the frame's Cartesian coordinate system are added as needed), and multiple clamping points can be defined in each process. For example, if clamping points 1 and 2 are set in process 1, and clamping points 3 and 4 are set in process 2, the mechanical boundary is the clamping sequence of clamping points 1, 2, 3, and 4. The fixture clamping point model can be defined in the simulation system or modeled and imported from the 3D design environment. The simulation system forms a clamping point assembly model library through the fixture models imported step by step. Furthermore, multiple mold clamping point models can be parameterized and standardized for modeling.

[0119] Welding assembly simulation: In the system structural component module, the sub-components of the welding assembly will form an assembly model based on the global coordinate system of the vehicle frame. The assembly of the welding assembly can be simulated in multiple processes. For example, process 1 sets up supplier-level parts 1 and 2, welds a and b, and process 2 sets up supplier-level part 3, welds c and d.

[0120] Welding path definition: In the system joint module, the welding path is generated by default; only the welding speed needs to be defined. In the system structural component module, the welding path is defined by process. For example, if process 1 sets weld 1 and weld 2, and process 2 sets weld 3, the welding path will be the route of welds 1, 2, and 3. Furthermore, the welding direction of each weld segment can be determined by one of two end-to-end welding directions.

[0121] It should be noted that the construction nodes of the fixture clamping point model are more than those in step S303. The reusable fixture clamping point model is built in the above steps and can be directly reused in multiple processes in parallel.

[0122] It should be further noted that the welding assembly simulation is only applied to the global simulation environment, and the local simulation environment for key parts does not need to be predefined.

[0123] Calculation and solution:

[0124] In the system joint module, the thermo-elastoplastic finite element method and the birth and death element technique are used for calculation. When the post-weld temperature is higher than the ambient temperature, it indicates that the system's default time setting is insufficient, and the maximum system solution time needs to be increased. After the temperature calculation is completed, the equivalent plastic strain also needs to be calculated.

[0125] In the system structural component module, the dimensionless stress field calculation results of the joints are mapped into the structural component assembly model according to the assembly joint layout requirements, and the calculation is performed using the inherent strain method and the birth and death element technique. To improve computational efficiency, a parallel computing mode can be set.

[0126] Post-processing results: In the post-processing interface of the system joint module, the welding process is simulated. In the temperature field, if the highest temperature of the joint exceeds 50% of the liquidus threshold or is less than the solidus temperature threshold, the shape parameters of the heat source model need to be reset in the pre-processing interface.

[0127] Within the system structural component module interface, a simulation navigation tree table is created, containing nodes such as products, manufacturing features, tooling, and fixtures. Each node can be grouped into sub-assemblies of the final assembly product, and manufacturing features such as welds associated with each level of product, tooling fixture clamping points, and tool models. Other nodes parallel to the aforementioned product, manufacturing feature, tooling, and fixture nodes can also be added to the navigation tree table.

[0128] Before performing the above calculations, you can select nodes that do not participate in the calculation, such as tools and fixtures, under the navigation tree table of the system structural components module.

[0129] Furthermore, to improve the operational efficiency of the simulation platform, the following user template customization function is proposed:

[0130] The visualization and simulation functions of the simulation navigation tree table in the system connector and structural component modules can be implemented using high-level programming languages ​​such as C++.

[0131] The post-processing interface of the system joint and structural component modules allows for zoom-in and dynamic display of the displacement field, stress-strain field, and temperature field of the complete welding cycle. It can generate curves showing the changes of specified variables at specified locations on the structural components and welds over welding time. It can display vector cloud maps comparing the deformation of the workpiece before and after welding. It can display the model's cross-sectional surface, allowing observation of contour lines and isosurfaces of the temperature and stress fields, and enabling querying and display of variable values ​​at any node in the model.

[0132] Furthermore, this application also includes: reuse of simulation schemes.

[0133] There are two ways to reuse simulation schemes: "Save As for Reuse" and "Reuse Process Clamping Scheme".

[0134] The "Save As" feature allows for reuse of files such as boot files, model files, mesh files, and assembly files contained in the simulation project files. This feature is enabled by setting up the "Save As" function in the system structure module.

[0135] The process clamping scheme reuse method allows the clamping point layout reuse function to be set in the system structural component module, so that the clamping scheme of the previous process can be copied to the subsequent process, thereby improving the efficiency of simulation work.

[0136] Simulation animation output

[0137] By setting the output animation duration or frame rate, video animation name, and save path in the system structural component module, the simulation system can output welding simulation video animations of simulated assemblies.

[0138] Beneficial effects:

[0139] This invention uses process planning and design analysis of the chassis welding sub-assembly, and the linkage of the "global-local" two-level simulation system module, to predict the trend and amount of welding deformation, and provide suggestions for product design improvement and optimization schemes for welding process in advance.

[0140] This invention adopts a "global-local-global" simulation technology approach, which can significantly shorten the simulation calculation time for large and complex welded assemblies, making it compatible with the rapid iteration of automotive manufacturing engineering and improving design and manufacturing efficiency.

[0141] This invention utilizes virtual analysis technology, which helps control welding thermal deformation and identifies prominent problems in process design in advance, thereby saving on process investment costs and production trial costs for subsequent part stamping and welding.

[0142] On the other hand, this application provides an electronic device, including: a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other through the communication bus; the memory stores a computer program, and when the computer program is executed by the processor, the processor performs the steps of the method.

[0143] On the other hand, this application provides a computer-readable storage medium storing a computer program executable by an electronic device, which, when run on the electronic device, causes the electronic device to perform the steps of the method described herein.

[0144] On the other hand, this application provides a simulation platform, including:

[0145] An electronic device for implementing the steps of the method described herein;

[0146] A processor that runs a program, and when the program runs, it executes the steps of the method from data output by the electronic device.

[0147] A storage medium for storing a program that, when run, executes the steps of the method on data output from an electronic device.

[0148] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A welding simulation method for a vehicle frame welding sub-assembly, characterized in that, The method includes the following steps: S1: Based on the welding process of the chassis welding sub-assembly, identify all supply-level parts and welding manufacturing characteristics; S2: Preprocess or simplify the 3D model of each supply-level part, input it into the simulation software, and build or input the weld 3D model associated with the supply-level part model to assemble it into a global 3D model; at the same time, build the local joint model associated with the global 3D model. S3: Based on the global and local two-level three-dimensional models, the first preset strategy is used for simulation to obtain the welding deformation and stress risk area of ​​the frame welding sub-assembly; S4: Based on the welding deformation and stress risk area of ​​the frame welding sub-assembly, the second preset strategy is used for simulation to obtain the target process design scheme of the frame welding sub-assembly.

2. The method according to claim 1, characterized in that, Step S3: Based on the global and local two-level three-dimensional models, simulation is performed using the first preset strategy to obtain the welding deformation and stress risk areas of the frame welding sub-assemblies, specifically including: S301: Evaluate the key parts of the global welding sub-assembly model and construct local models of the key parts; preset the feature dimensions, material properties, mechanical and temperature boundaries, heat input, heat source model and parameters of the local model, and preset the mesh generation parameters of the local model to start the finite element calculation program based on the thermo-elastic-plastic principle to obtain the first simulation data of the key parts; the first simulation data includes at least the temperature field and strain field results data of the key parts. S302: Based on the global welding sub-assembly model, a simplified welding assembly fixture model, material properties, and welding sequence of the welding sub-assemblies are preset, and the mesh generation parameters of the global model are preset. The strain field result data in the first simulation data is mapped to the global model, and the finite element calculation program based on the inherent strain principle is started to obtain the second simulation data of the global model. The second simulation data includes at least the stress-strain field result data of the global model.

3. The method according to claim 2, characterized in that, In step S301, the local simulation uses finite element simulation technology that sequentially couples temperature field and stress field for key parts, and the mesh size ratio between the global model and the refined local model is configured to be ≥ preset ratio, which facilitates smooth adaptation of the accuracy of the meshes of the two-level models.

4. The method according to claim 3, characterized in that, Step S301's local simulation employs finite element simulation technology that sequentially couples temperature and stress fields for key components, specifically including: The local simulation includes the welding heating stage and the post-weld cooling stage; If the highest temperature during the welding heating stage is less than the solidus temperature threshold or greater than the preset ratio of the liquidus temperature threshold, the configuration parameters of the heat source model will be adjusted. If the temperature of the critical parts is higher than the ambient temperature when the local simulation ends, the system parameters that take the longest time to solve should be allowed to cool down completely. If the temperature field calculation is completed and the above conditions are met, the melting depth and melting width parameters of the molten pool are measured and statistically analyzed in the time domain above the solidus temperature of the simulated base material. The results are compared with the design target value. If the results are greater than or equal to the design target value, the strain field results are smoothed and output as the first simulation data.

5. The method according to claim 4, characterized in that, In step S302, the global three-dimensional model of the chassis welding sub-assembly simulated in step S302 is split into a multi-process joint welding and assembly model corresponding to the actual production process. In the simulation performed in steps S301 to S302, relevant attributes are predefined. The relevant attributes include at least: material properties, heat input, heat source model configuration, mechanical boundary, temperature boundary, welding composition process assembly, and welding path. In step S302, the predefined relevant attributes are pre-configured based on the production process distribution, and a clamping point model is constructed in this step.

6. The method according to claim 5, characterized in that, Step S4: Based on welding deformation and welding stress risk areas, a second preset strategy is adopted to obtain the target process parameters for the frame welding sub-assembly, specifically including: S401: Based on the second simulation data of the frame welding sub-assembly, the key welding risk areas are identified in accordance with the design requirements, namely the welding deformation and welding stress risk areas; S402: Optimize process data based on the distribution characteristics of the risk area; the distribution characteristics include at least the location, shape, and corresponding fixture clamping point arrangement of deformation and stress risks. S403: Input the optimized process data into the global 3D model, preset the mesh generation parameters, and then perform local-global simulation iterations using the thermo-elastic-plastic method and the inherent strain method until the peak values ​​of deformation and stress risk zones are all less than the set thresholds, and output the target process data; the target process data includes at least: welding heat input, welding path and fixture clamping point model.

7. A welding simulation system for a vehicle frame welding sub-assembly, characterized in that, The system includes: The modeling module is configured to build a 3D weld model associated with the frame welding sub-assembly and its supply-level sub-components, build a simplified 3D model of the frame welding sub-assembly fixture, and build local 3D models of key parts of the frame welding sub-assembly and their corresponding mechanical boundaries. The assembly module is configured to identify and preprocess the 3D models of all supply-level components based on the chassis welding sub-assembly structure and welding process. Then, the preprocessed component models and weld models are input into the simulation software to complete the process-level assembly. At the same time, the simplified model of the welding sub-assembly fixture is input into the simulation software to form a virtual welding and assembly model. The first processing module is configured as a local three-dimensional model and a global welding assembly model of key parts of the frame welding sub-assembly. It adopts a first preset strategy to obtain the risk areas of welding deformation and welding stress of the welding sub-assembly. The second processing module is configured to obtain the target process design scheme for the chassis welding sub-assembly based on the risk area of ​​the global three-dimensional model and using the second preset strategy.

8. An electronic device, comprising: The system comprises a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other via the communication bus; characterized in that the memory stores a computer program, which, when executed by the processor, causes the processor to perform the steps of the method described in any one of claims 1-6.

9. A computer-readable storage medium, characterized in that, The device stores a computer program executable by an electronic device, which, when run on the electronic device, causes the electronic device to perform the steps of the method as described in any one of claims 1 to 6.

10. A simulation platform, characterized in that, It should also include: An electronic device for implementing the steps of the method according to any one of claims 1 to 6; A processor that runs a program that, when the program is running, performs the steps of the method according to any one of claims 1 to 6 from data output by an electronic device. A storage medium for storing a program that, when run, performs the steps of the method according to any one of claims 1 to 6 on data output from an electronic device.

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