Strength and fatigue analysis method and equipment for welded integrated planet carrier

Abstract

The invention provides a strength and fatigue analysis method and equipment for a welded integrated planet carrier, belongs to the technical field of welding processes and weld strength and fatigue evaluation, and establishes a temperature / phase dependent material performance parameter library, and adopts Johnson-Mehl-Avrami and Koidinen-Marburst formulas to process phase change kinetics. And a welding process simulation system is constructed through single-claw model simplification, grid gradient control and a 3D Gaussian heat source model. Data transmission and rebalance verification are achieved, and it is ensured that the displacement error is smaller than or equal to 0.85%. And supplementing a complete model and setting boundary conditions, introducing 50% residual stress relaxation correction, dividing the welding seam / heat influence area into 10 groups according to the yield strength difference, and calculating the fatigue life by adopting a Basquin formula. According to the method, through multi-physics field coupling and sub-model subdivision, accurate evaluation of the static strength and the fatigue life of the welding structure is achieved, and the application reliability is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of welding process and weld strength and fatigue evaluation, and particularly relates to a welding integrated planetary carrier strength and fatigue analysis method and equipment. BACKGROUND

[0002] Integrated Computational Materials Engineering (ICME) is defined as combining the calculated material information with product performance and manufacturing process, which contains material microstructure models of different scales, microstructure-performance models, material databases, cost analysis models, etc. At present, ICME has become an emerging cross-discipline and is attracting more and more attention. The simulation analysis method based on the ICME idea is also widely used in various important process and key part performance prediction.

[0003] Due to the material phase change and the sharp change of temperature near the weld during the welding process, the position often has a great residual stress after the welding is completed, and the residual stress will affect the fatigue life of the weld together with the load suffered by the workpiece. On the other hand, the occurrence of material phase change behavior during the welding process changes the mechanical properties of the material itself, thereby also affecting the fatigue behavior of the part. Therefore, it is necessary to introduce the integrated computing idea, that is, it is necessary to consider the influence of the welding process characteristics in the weld fatigue life prediction process.

[0004] In the related art, in order to improve the efficiency, a unified coarse grid is adopted, although the calculation amount can be reduced, the local details of the weld and the heat affected zone are covered, the stress concentration caused by the sharp heat input in the region cannot be captured, and the role of evaluating the weld strength is lost.

[0005] The welding process simulation and strength fatigue analysis in the related art need to transfer data across software, but the mesh.inp file output by the welding simulation contains BAR elements, SHELL elements or property attributes which are not needed for strength analysis and conflict with the software, and the import will cause analysis error.

[0006] In the related art, the planetary gear pin shaft is not added in the strength fatigue analysis, so that the torque load cannot be transmitted through the planetary gear->pin shaft->planetary carrier, and can only be simplified as directly applying the load on the claw body, which deviates greatly from the actual stress.

[0007] When the welding residual stress is calculated, relaxation will occur due to the load action, and the original residual stress after welding is calculated, which will overestimate or underestimate the stress level of the structure, resulting in that the safety factor calculation error exceeds the threshold. The weld and the heat affected zone are regarded as the same material, the average yield strength is adopted, the performance gradient caused by the phase change difference in the region is ignored, and the risk of local insufficient strength is covered. SUMMARY

[0008] The present application provides a welding integrated planetary carrier strength and fatigue analysis method, the method takes a certain type of gearbox 20MnCr5 welding planetary carrier as the analysis object, based on the integrated computing idea, first simulates the planetary carrier electron beam welding process through welding process simulation, analyzes the post-weld residual stress accumulation and material microstructure evolution characteristics. Subsequently, the planetary carrier welding residual stress information and material evolution information are introduced into the strength and fatigue analysis stage through data processing, thereby realizing the strength and fatigue simulation analysis of the planet under the condition of considering the material welding process characteristics.

[0009] The method comprises: S101: building a material performance parameter library containing temperature and phase dependent functions; S102: processing the geometry and mesh model of the welded planetary carrier, simplifying the complete model into a single claw model, dividing the front planetary carrier and output shaft into matrix, heat affected zone and weld seam parts, and setting different mesh sizes; S103: determining the process parameters and boundary conditions required for welding simulation; S104: establishing a welding process simulation model, which integrates the material performance parameter library, geometry and mesh model, process parameters and boundary conditions, and includes a welding heat source model and welding trace definition; S105: retrieving the organization evolution information, residual stress distribution, structural deformation and mesh node information at the last time step of the welding process simulation, and processing the information in a general mesh model processing software to generate transferable data; S106: verifying the accuracy of the transferable data through rebalancing analysis; S107: supplementing the single claw model, adding planet pin shaft and perfecting the remaining parts of the front planetary carrier and output shaft, and setting the mesh size of the supplemented parts; S108: setting the boundary conditions for strength and fatigue analysis according to the actual structure and load state of the planetary carrier; S109: introducing the residual stress distribution, structural deformation and mesh node information into the strength and fatigue analysis model, applying constraints and loads, and then performing strength analysis, grouping the weld seam sub-models and calculating the fatigue life using the Basquin formula.

[0010] According to another embodiment of the present application, an electronic device is provided, comprising a memory, a processor and a computer program stored on the memory and executable on the processor, wherein the processor implements the steps of the welding integrated planetary carrier strength and fatigue analysis method when executing the program.

[0011] From the above technical solutions, the present application has the following advantages: The welding integrated planet carrier strength and fatigue analysis method provided by the application controls the actual error of phase change proportion calculation within a threshold range by establishing a temperature-dependent and phase-dependent material performance parameter library and processing phase change kinetics parameters by using Johnson-Mehl-Avrami, so as to provide accurate material input for thermal field and stress field simulation. The complete planet carrier is simplified into a single claw model, and differential mesh design is adopted for the welding seam, heat affected zone and matrix, so that the overall mesh quantity is controlled within 1 million, the simulation efficiency is improved, and local severe thermal stress changes can be accurately captured. Through cleaning of invalid units, standardization of unit set and contact surface definition, and verification by rebalancing analysis, it is ensured that the data transmission is not distorted. The planet wheel pin shaft and the remaining structure of the front planet carrier and the output shaft are supplemented, so as to restore the real transmission path of the torque from the planet wheel to the planet carrier; friction contact, binding connection and coupling constraint are set, so as to simulate the actual assembly and stress state. The welding seam / heat affected zone is split according to the yield strength difference, and the fatigue life is calculated by using the Basquin formula. Finally, the strength and fatigue analysis results are within the preset range of the actual service state, the planet carrier fatigue margin can be accurately reflected, the calculation accuracy is ensured, the efficiency and reliability are improved through the simplified single claw model and the verification of rebalancing analysis, and finally the strength and fatigue evaluation method of the welded planet carrier is provided, which can be used for design optimization and service reliability evaluation of the planet carrier. BRIEF DESCRIPTION OF DRAWINGS

[0012] In order to more clearly illustrate the technical solutions of the present application, the drawings required to be used in the description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0013] Figure 1 The welding integrated planet carrier strength and fatigue analysis method flowchart; Figure 2 The welding integrated planet carrier strength and fatigue analysis method flowchart; Figure 3 The five-claw planet carrier welding process simulation stage geometric model schematic diagram; Figure 4 The five-claw planet carrier welding process simulation stage geometric model embodiment schematic diagram; Figure 5 The five-claw planet carrier welding process simulation stage supplemental model schematic diagram; Figure 6 The integrated complete planet carrier model schematic diagram; Figure 7 Electronic device schematic diagram. DETAILED DESCRIPTION

[0014] As Figure 1As shown, the strength and fatigue analysis method for welded integrated planetary carriers involved in this invention involves simulating and modeling the welding process. First, a material property database is established, with relevant material properties taken as temperature-dependent functions. To improve the computational efficiency and convergence of the model, the complete welded planetary carrier model is simplified into a single-claw model. Simultaneously, to ensure sufficiently high simulation accuracy of the weld location, the front planetary carrier and output shaft structures are divided into sub-models, processed into a base part, a heat-affected zone part, and a weld part, respectively. The heat-affected zone and weld sub-models undergo mesh refinement. For simulation data transfer and processing, after the welding simulation is completed, the microstructure evolution, residual stress distribution, structural deformation, and mesh node information of the material at the last time step of the simulation are exported. These files are then edited using general mesh model processing software, allowing them to be imported into general finite element analysis software for subsequent strength and fatigue analysis.

[0015] In the strength and fatigue analysis modeling stage, the material performance parameters of the planetary carrier are derived from the welding process simulation results. In terms of model processing, the single-claw planetary carrier model from the welding process simulation is supplemented into a complete model so that it can be used for setting loading conditions in the strength and fatigue simulation stage. To express the differences in the mechanical properties of the weld and heat-affected zone materials at different locations, relevant sub-models are regrouped to achieve accurate modeling and analysis considering changes in local mechanical properties.

[0016] This invention introduces residual stress into the strength and fatigue analysis of planetary carriers, enabling the prediction of the actual stress state of welded planetary carriers. By importing information on changes in the microstructure of welding into the model, it expresses the differences in material mechanical properties at different locations of the planetary carrier caused by welding. Through this integrated calculation method, the engineering problem of the inability to accurately simulate and evaluate welded products is solved.

[0017] The following describes in detail the strength and fatigue analysis method for welded integrated planetary carriers involved in this application. Specific details, such as particular system structures and technologies, are presented for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application can also be implemented in other embodiments without these specific details.

[0018] It should be understood that, when used in this specification, terms include indicating the presence of a described feature, integral, step, operation, element, and / or component, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or collections thereof. The terms include, encompass, have, and variations thereof mean including but not limited to, unless otherwise specifically emphasized.

[0019] The statements such as "one embodiment" or "some embodiments" described in this application mean that one or more embodiments of this application include the specific features, structures, or characteristics described in that embodiment. Therefore, the statements such as "in one embodiment," "in some embodiments," "in other embodiments," and "in still other embodiments" in this application do not necessarily refer to the same embodiment, but rather mean one or more, but not all, embodiments, unless otherwise specifically emphasized.

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Please see Figure 2 The diagram shows a flowchart of a method for strength and fatigue analysis of a welded integrated planetary carrier in a specific embodiment. The method includes: S101: Build a planetary carrier material performance parameter library. The parameter library includes material thermophysical parameters, mechanical property parameters and phase transformation kinetic parameters, and the parameters are temperature-dependent and phase-dependent functions.

[0022] In some embodiments, the planetary carrier material is 20MnCr5. The parameter library includes thermal properties such as thermal conductivity, specific heat capacity, and density, as well as mechanical properties such as elastic modulus, Poisson's ratio, yield strength, and phase transformation kinetic parameters. The temperature range is defined as 1500℃-50℃, and the phase structure is a function of austenite, ferrite, bainite, and martensite. The material performance parameters can be obtained by JMatPro software.

[0023] To convert phase transition kinetics results into phase transition kinetics parameters required for process simulation, Johnson-Mehl-Avrami Equation 1 is used for isothermal phase transitions: Formula 1 In the formula, For the sake of proportion, For equilibrium phase ratio, and These represent the phase transition time and the incubation period, respectively. This is the material coefficient.

[0024] For non-isothermal phase transitions, Koistinen-Marburge Equation 2 is used to convert the phase transition kinetics results into parameters required for process simulation.

[0025] Formula 2 In the formula, Indicates temperature. For material coefficients, This indicates the martensite initiation temperature.

[0026] The changes in material properties with temperature and phase structure in this embodiment form the basis for the coupled simulation of thermal field, microstructure field, and stress field during welding. By processing the phase transformation kinetic parameters with specific formulas, the phase transformation law of the material during the welding heating-cooling process can be accurately described, providing material input that conforms to reality for the simulation.

[0027] S102: Perform geometric and mesh modeling on the welded planetary carrier, simplify the complete model into a single-claw model, divide the front planetary carrier and output shaft into the base body, heat-affected zone and weld seam, and set different mesh sizes.

[0028] In some embodiments, the object being processed is a five-jaw planetary carrier, comprising a front planetary carrier 1 and an output shaft 2, such as... Figure 3 and Figure 4 As shown.

[0029] Figure 4 It has a front planetary carrier base 3, a front planetary carrier heat-affected zone 4, a front planetary carrier weld 5, an output shaft weld 6, an output shaft heat-affected zone 7, and an output shaft base 8.

[0030] To improve computational efficiency during the process simulation phase, the planetary carrier is modeled as a 1 / 5 scale model, i.e., a single-jaw model. To ensure the calculation accuracy of the planetary carrier welds and heat-affected zone, the front planetary carrier and output shaft components are further subdivided into the base body, the heat-affected zone, and the weld.

[0031] Furthermore, the total width of the weld is 4mm, and its mesh size is set to 0.5mm. The width of the heat-affected zone is 8mm, and its mesh size is set between 0.5-1mm. The mesh size of the base portion is between 1-10mm. The total number of mesh models of the planetary carrier is approximately 70W.

[0032] In some specific embodiments, S102 specifically includes the following steps: Step S1021: Utilizing geometric symmetry, select a single claw of the five-claw planetary carrier as the analysis object to construct a 1 / 5 scale model; remove redundant claw bodies and auxiliary connectors that are not welded together outside the plane of symmetry, retain the geometric features of the welding area between the front planetary carrier and the output shaft, and ensure that the morphology of the welded joint and the assembly relationship of the components in the simplified model are consistent with the original model.

[0033] In some embodiments, a plane passing through the center of the planetary carrier and bisecting a certain claw is identified, and after mirror cutting, redundant structures outside the symmetrical plane are deleted, while core areas such as the front planetary carrier claw cavity and the output shaft welding end are retained.

[0034] Step S1022: Divide the simplified front planetary carrier and output shaft into a base part, a heat-affected zone part, and a weld part; the boundary of the heat-affected zone is determined according to the temperature influence range of the welding thermal cycle; the weld part is a three-dimensional solid model extracted based on the geometric parameters of the actual weld width and reinforcement height of the electron beam welding joint; the base part is the remaining main structure of the front planetary carrier and output shaft after removing the heat-affected zone and the weld.

[0035] In some embodiments, a thermal simulation module is used to simulate thermal cycling, determine the temperature threshold of the heat-affected zone to divide the spatial range, and import CT scan images of electron beam welding joints to reverse generate a three-dimensional solid model.

[0036] Considering the different characteristics of melting, solidification phase transformation in the weld zone, mid-temperature phase transformation in the heat-affected zone, and elastic deformation of the matrix during welding, the subdivision of the region allows for the assignment of material properties based on each phase transformation mechanism and mechanical response, thereby improving the relevance of the simulation.

[0037] Step S1023: The weld area uses a high-precision volume mesh with a mesh size of 0.5 mm or less; the heat-affected zone mesh size is set to 0.5-1 mm; the base area uses a coarse mesh with a size of 1-10 mm; the mesh type is preferably hexahedral dominant or tetrahedral adaptive to balance calculation accuracy and efficiency.

[0038] In some embodiments, the weld zone uses a hexahedral / ring-shaped swept mesh, and the heat-affected zone uses a gradient transition mesh aligned with the weld mesh nodes. The base region uses a structured hexahedral or large-scale tetrahedral mesh, with mapping to improve efficiency.

[0039] It can be seen that the temperature gradient in the welding zone is weld > heat-affected zone > matrix, and the stress gradient is weld root > heat-affected zone > matrix body. These gradients change rapidly with space. Small meshes in high gradient zones capture transient changes, while large meshes in low gradient zones reduce computational load, achieving a balance between accuracy and efficiency.

[0040] Step S1024: Use a mesh quality assessment algorithm to screen low-quality elements; correct low-quality elements by mesh re-dividing and node adjustment to ensure that the overall mesh quality meets the simulation convergence requirements.

[0041] In some embodiments, the tetrahedral mesh of the weld / heat-affected zone needs AR ≤ 5 and S ≤ 0.8; the hexahedral mesh of the matrix needs AR ≤ 10 and S ≤ 0.5; low-quality elements are preferentially re-meshed locally near the weld joint. Distorted elements lead to ill-conditioned stiffness matrix, resulting in spurious oscillations or deviations in stress and displacement calculations; quality assessment and correction ensure the regularity of element shape, making the stiffness matrix diagonally dominant, thus improving solution convergence and result reliability.

[0042] Step S1025: Count the total number of elements in the complete mesh model and gradually simplify the mesh in non-critical areas such as the matrix; compare the stress peak deviation under different mesh numbers, and determine the final mesh number when the deviation is <5%, and control the total number of meshes to within 1 million.

[0043] In some embodiments, after initial mesh statistics, the matrix region mesh is coarsened from 1-10 mm to 2-20 mm, and the quantity is locked when the comparison deviation is <5%.

[0044] This embodiment considers that too many meshes increase computational resource consumption, while too few meshes lead to discretization errors. Convergence verification ensures that the accuracy at the weld root meets requirements, reducing the mesh count in non-critical areas to achieve a balance between efficiency and accuracy. Fine meshes are used for the weld and heat-affected zone to accurately capture the drastic thermal and mechanical changes in this area, while coarser meshes are used for the substrate to balance computational efficiency. Overall mesh count control ensures simulation convergence.

[0045] S103: Determine the welding simulation process parameters and boundary conditions. The process parameters include welding speed, welding power, and welding time. The boundary conditions include welding constraint settings and welding air cooling rate.

[0046] In some embodiments, welding simulation process parameters are obtained from welding process cards, specifically including welding speed, welding power, and welding time. Boundary conditions are divided into two categories: one is welding constraint settings, also known as displacement field constraints, which are determined based on the actual clamping state of the planetary carrier to simulate the fixing method during welding. The other is welding air cooling rate, also known as temperature field constraints, which simulate the natural cooling process of the workpiece in the air after welding.

[0047] This embodiment ensures that the heat input of the welding process simulation is completely matched with the boundary environment to the actual production conditions, avoiding the distortion of the thermal and stress field simulation results caused by deviations in parameters or constraints, and providing a guarantee for obtaining real residual stress and deformation data.

[0048] S104: Establish a welding process simulation model. The welding process simulation model integrates a material performance parameter library, geometric and mesh models, process parameters and boundary conditions, and includes a welding heat source model and welding trace definition.

[0049] In some embodiments, core data such as materials, geometry, process, and boundaries are integrated, and the spatial heat flux density distribution characteristics of electron beam welding are reproduced through a 3D Gaussian heat source model. The welding trace defines the heat source movement path, and together they construct a complete welding process simulation logic to achieve coupled calculation from heat input to stress and deformation output. This embodiment forms a simulation model covering all elements of welding, ensuring that the heat distribution, phase transition, and stress evolution processes of electron beam welding can be accurately simulated.

[0050] S105: Perform data transfer and processing, export the microstructure evolution information, residual stress distribution, structural deformation and mesh node information after welding process simulation, and perform operations such as importing, deleting, creating element sets, contact surfaces and adding command lines in general mesh model processing software.

[0051] In some embodiments, after the electron beam welding simulation of the planetary carrier is completed, the key data of the last time step of the process simulation is exported, which is the key data of the stable state after welding. Specifically, the material microstructure evolution information stored in material.inp, the residual stress distribution stored in sigma.txt and hardini.txt, the structural deformation stored in mesh.inp, and the mesh node information stored in nodes.inp.

[0052] Perform five steps in the general-purpose HyperMesh mesh model processing software: (1) Import the mesh.inp file and delete the BAR unit, SHELL unit and property attribute; (2) Create a unit set for each component and delete the ELSET=unit set definition part in the ELEMENT line; (3) Establish contact surfaces / remove relationships and place them at the end of the mesh.inp file; (4) Add the command line *include,input=mesh.inp to the material.inp file and import material.inp; (5) Establish the corresponding constraint node set according to the component assembly relationship and add the command line *Element Output,directions=YES, position=CENTROIDAL MISES.

[0053] The data format output from the welding process simulation in this embodiment does not fully match the requirements of subsequent rebalancing and strength analysis software. By exporting key data and performing cleaning, standardization, and correlation operations, the data can be converted into a conflict-free format that can be recognized by subsequent software, thus enabling data transfer across software.

[0054] S106: Perform rebalancing analysis. Import the data transferred in step S105 into the general finite element analysis software. Set boundary conditions based on the constraints of the last time step of the process simulation. Verify the accuracy of the data transfer by comparing the displacement and Mises stress levels.

[0055] In some embodiments, all data processed in S105 (material.inp, mesh.inp, etc.) are imported into general-purpose finite element analysis software. Then, based on the constraints of the last time step of the welding process simulation, the software fully reproduces the displacement and temperature field constraints, such as those related to clamping and fixing. A rebalancing calculation is run, and the calculated structural displacement is extracted. Optionally, the displacement is 7.074e-6 mm, approaching zero. Finally, the Mises stress data from the last time step of the welding process simulation is extracted and compared with the Mises stress data from the rebalancing analysis step. The maximum error between the two is calculated, and the accuracy of data transfer is evaluated based on whether the displacement approaches zero and whether the stress error is less than a threshold.

[0056] It can be seen that if the data transmitted by S105 is accurate, the model should be in mechanical equilibrium during the rebalancing analysis that reproduces the original constraints, with no additional displacement of the structure and the stress distribution basically consistent with the original process simulation; otherwise, it indicates that there is data loss or distortion in the data transmission. It is crucial to ensure the reliability of the data transmitted to subsequent analyses to avoid invalidating subsequent strength and fatigue analysis results due to data distortion.

[0057] S107: Process the geometric and mesh models for strength and fatigue analysis. Based on the single-claw model in step S102, add planetary gear pins and improve the remaining parts of the front planetary carrier and output shaft. The mesh size of the supplemented model is 1-10mm.

[0058] In some specific embodiments, S107 specifically includes the following steps: S1071: Import the geometry and mesh model of the single-claw planetary carrier for welding simulation after step S102 into the general mesh model processing software.

[0059] In some embodiments, the imported model includes the base portion, heat-affected zone portion, weld portion, and corresponding mesh as defined in step S102, ensuring that the model retains the mesh features of key areas from the welding simulation stage. Optionally, the weld has a 0.5mm mesh, and the heat-affected zone has a 0.5-1mm mesh. Based on the single-claw model used for welding simulation, the geometric and mesh continuity between subsequent supplementary structures and the original key welding areas is ensured.

[0060] S1072: Based on the actual assembly dimensions of the planetary carrier and the load transfer requirements, establish the geometric model of the planetary gear pin shaft, with the axis of the planetary gear pin shaft aligned with the axis of the claw hole of the single-claw planetary carrier.

[0061] In some embodiments, the diameter, length, and stepped structure of the planetary gear pin are determined based on the diameter of the planet carrier claw bore, the inner diameter of the planetary gear, and the bearing assembly requirements. During modeling, both ends of the pin are aligned with the assembly surfaces of the planet carrier claw bore and the inner diameter of the planetary gear, respectively, to ensure coaxiality of the axes.

[0062] S1073: Based on the 1 / 5 structure of the single-claw planetary carrier and the five-claw planetary carrier, the single-claw model is replicated and the geometric and mesh model of the remaining claw structure of the front planetary carrier is improved according to the circumferential distribution law.

[0063] In some embodiments, using the rotation center of the single-claw model as a reference, the single-claw model is replicated at angular intervals of 360° / number of claws, and the positions of the claws are adjusted to ensure that each claw is evenly distributed along the circumference. The remaining structures of the front planetary carrier, such as connecting spokes and the central hub, are added between the claws to ensure the geometric continuity between each claw and the central structure. The structural and mesh features of each claw are kept consistent, making the stress distribution analysis under multi-claw loads more accurate.

[0064] S1074: Based on the flange connection or spline connection method between the planetary carrier and the output shaft, supplement the geometry and mesh model of the extension section and connection section of the output shaft that are not included in the single-jaw model.

[0065] In some embodiments, the supplementary output shaft structure includes a welded flange to the front planetary carrier, a splined shaft, a bearing mounting section to other components of the gearbox, and an output end spline. During modeling, it is ensured that the supplementary section is coaxial with the existing output shaft portion in the single-jaw model, and that the connecting surfaces fit together without gaps. A solid structure is provided for setting bearing constraints and spline constraints in step S108, ensuring that the application positions of the boundary conditions are consistent with the actual assembly, thus improving the realism of the boundary conditions in strength and fatigue analysis.

[0066] S1075: As Figure 5 and Figure 6 As shown, the mesh size of the supplementary model in steps S1072, S1073, and S1074 is set to 1-10mm. The supplementary model and the single-claw model are integrated into a complete planetary carrier model, and the total number of meshes is controlled to be within 1 million.

[0067] In some embodiments, the planetary gear pin shaft, the remaining claw body of the front planetary carrier, and the supplementary section of the output shaft are meshed, with the mesh size controlled between 1-10mm. A 10mm mesh is used for non-critical stress areas, and a 1-5mm mesh is used for the output shaft connection section near the weld. The supplementary model is integrated with the original single-claw model through node merging, surface bonding, and other methods. The total number of meshes is counted to ensure it does not exceed 1 million.

[0068] This embodiment takes into account that if the mesh size of the supplementary model is too fine, the overall mesh number will increase dramatically, reducing computational efficiency; if it is too coarse, it will cause deviation in stress calculation in non-critical areas. A range of 1-10mm can control the overall computational load while ensuring the calculation accuracy in non-critical areas.

[0069] S108: Set the boundary conditions for strength and fatigue analysis, apply constraints based on the positions of planetary carrier bearings, splines, etc., and apply loads to the planetary gear pins based on the actual load conditions.

[0070] In some embodiments, a four-step setup is performed in general-purpose finite element analysis software: 1. Set the contact relationship: The planetary gear shaft and the planetary carrier claw body hole are set to frictional contact. The friction coefficient is 0.1-0.3 according to the lubrication condition. At the same time, the contact stiffness parameter is set to ensure no penetration. 2. Set up connection relationship: Set the single claw model used for welding simulation to be bound to the supplementary remaining claw body and the output shaft extension to make the displacement of the contact surface nodes completely coordinated; 3. Set up coupling units: Create coupling units at the planetary carrier bearing support position, the planetary gear shaft and planetary gear contact area, and the planetary carrier external spline position, respectively, and couple the bearings of all nodes in each area radially and the splines to a master node; 4. Apply constraints and loads: Apply radial translational freedom constraints to the coupled master nodes at the bearing support position, apply rotational freedom constraints to the coupled master nodes at the external spline position, and apply a torque load around the Z-axis to the coupled master nodes at the contact area between the planetary gear shaft and the planetary gear, based on the maximum torque condition of the actual service of the planetary carrier.

[0071] It can be seen that by simulating the actual force transmission between the planetary gear shaft and the planetary carrier hole through frictional contact, the binding connection ensures the mechanical continuity between the supplementary structure and the original model, and the coupling unit simplifies the application of constraints / loads in complex areas; the constraint simulation of the positioning load of the actual assembly simulates the torque of the actual service, together constructing a realistic mechanical boundary environment.

[0072] S109: Perform strength and fatigue analysis. Introduce the residual stress distribution, structural deformation, and mesh node information from step S105 into the model. Take 50% of the residual stress level to account for the relaxation effect. Apply loads and constraints and then perform the analysis. Divide the weld and heat-affected zone sub-models into 10 groups according to the yield strength difference. Use the Basquin formula to calculate the fatigue life.

[0073] In some specific embodiments, S109 specifically includes the following steps: S1091: In the general finite element analysis software, the residual stress distribution (sigma.txt / hardini.txt), structural deformation (mesh.inp), and mesh node information (nodes.inp) transferred in step S105 are imported into the complete integrated planetary carrier geometry and mesh model constructed in step S107, and data mapping is achieved through node number matching.

[0074] In some embodiments, the residual stress components in sigma.txt, the node deformation coordinates in mesh.inp, and the node position information in nodes.inp are mapped one-to-one to the nodes of the complete model using general-purpose finite element analysis software, according to the node numbers. For shared node regions between the welding simulation model and the complete model, values ​​are directly assigned; for non-shared node regions, linear interpolation is used for supplementation. Utilizing the uniqueness of the node numbers, the initial state data such as residual stress and deformation obtained from the welding process simulation are accurately transferred to the strength and fatigue analysis model, ensuring that the initial mechanical state of the analysis model is consistent with the actual state after welding.

[0075] S1092: Adjust the imported residual stress distribution data by multiplying the residual stress components of each node by 50% to account for the effect of residual stress relaxation.

[0076] In some embodiments, in the stress editing module of the software, the residual stress components of each imported node are uniformly multiplied by 0.5; the adjustment range covers the entire model, focusing on ensuring the accuracy of residual stress correction in welds and heat-affected zones, which can approximately reflect the attenuation characteristics of residual stress in actual service.

[0077] S1093: Apply the set bearing support constraints, external spline rotation constraints, and planetary gear shaft torque loads to the strength and fatigue analysis model to ensure that the positions of the constraints and loads correspond to the model nodes.

[0078] In some embodiments, the torque load defined in step S108 is applied to the coupled master node of the planetary gear shaft contact area, and the load is distributed to all nodes in the area through the coupling unit; at the same time, the radial constraint of the bearing support position and the rotational constraint of the external spline are activated to ensure that the constraints are effective. This ensures that the load and constraint conditions of the strength and fatigue analysis are real and reliable, and that the calculated stress distribution can accurately reflect the stress state of the planetary carrier during service.

[0079] S1094: In general finite element analysis software, extract the yield strength data of each element in the weld and heat-affected zone sub-model, divide the sub-model into 10 element groups according to the numerical difference of yield strength, and assign the yield strength parameters of the corresponding region to each element group.

[0080] In some embodiments, the yield strength of each element in the weld and heat-affected zone is extracted. The data comes from the material property parameter library of step S101 and the microstructure evolution information of welding simulation, such as the higher yield strength in the martensite region than in the ferrite region. A clustering algorithm is used to group elements with similar yield strengths into 10 groups, and each group of elements is assigned a corresponding yield strength parameter.

[0081] In this embodiment, the proportions of martensite and ferrite in the weld and heat-affected zone vary with location during the welding process, resulting in differences in yield strength. After grouping, stress can be calculated separately for the material properties of different regions, avoiding errors caused by using the average yield strength.

[0082] S1095: Solve the operational strength and fatigue analysis, calculate the Mises stress distribution of the model to complete the static strength analysis; based on the stress amplitude results, use Basquin formula 4 to calculate the fatigue life of the weld and heat-affected zone, and output the minimum safety factor.

[0083] Formula (4) In the formula, The stress amplitude, , All of these are material constants.

[0084] In some embodiments, in static strength analysis, the Mises stress of each element in the model is extracted and compared with the yield strength of the corresponding element group to determine whether there are regions where the stress exceeds the yield strength; in fatigue analysis, the stress amplitude σ of the weld and heat-affected zone is extracted. a Substituting into formula 4, where , Given the fatigue constant of the 20MnCr5 material in step S101, calculate the fatigue life. The safety factor is calculated by combining the design life and the safety factor = calculated life / design life, and the minimum safety factor is output.

[0085] The static strength analysis in this embodiment evaluates whether the structure has undergone plastic deformation by determining whether the stress exceeds the material's yield strength. The Basquin formula describes the power function relationship between stress amplitude and fatigue life, and can calculate the number of cycles required for the material to reach fatigue failure based on the stress amplitude, thereby evaluating fatigue performance.

[0086] In one embodiment of the present invention, based on step S103, the following is a possible embodiment and its specific implementation will be described in a non-limiting manner. S103 specifically includes the following steps: Step S1031: Extract the specific values ​​of the welding process parameters from the welding process card or database.

[0087] Specifically, parameters such as welding speed, welding power, and welding time are read through data parsing algorithms, and these parameters are converted into an input format acceptable to the simulation software.

[0088] Step S1032: Define displacement constraint boundary conditions based on the planetary carrier welding clamping state.

[0089] Specifically, a geometric selection algorithm is used to identify the clamping contact surfaces, and node sets are applied to constrain the degrees of freedom of these surfaces, such as fixing the translational degrees of freedom of the clamping surfaces. Multi-point constraints are managed through constraint equations to simulate the actual clamping effect.

[0090] Step S1033: Set the temperature field boundary conditions to simulate the air cooling process.

[0091] Specifically, a convective heat transfer coefficient is applied through a surface heat exchange model, where the heat transfer coefficient value is calculated based on the ambient temperature and surface emissivity, and a time-dependent function is used to define the cooling stage.

[0092] Step S1034: Integrate process parameters and boundary conditions into the simulation model input file.

[0093] Specifically, the parameters are mapped to the corresponding nodes and elements of the finite element model, such as by modifying the parameter and boundary condition sections in the input file (inp), and verifying data format compatibility.

[0094] Step S1035: Check the rationality of process parameters and boundary conditions using a parameter verification algorithm.

[0095] Specifically, pre-simulation tests were run, and the upper and lower limits of welding power were evaluated using a parameter sweep method. Parameters were adjusted based on convergence analysis to ensure simulation stability. Convergence and rationality were checked by testing extreme values ​​of the parameters in the pre-simulation tests.

[0096] In one embodiment of the present invention, based on step S104, the following is a possible embodiment and its specific implementation will be described in a non-limiting manner. S104 specifically includes the following steps: S1041: Import the planetary carrier material performance parameter library from step S101 into the welding process simulation model.

[0097] In some embodiments, material performance parameters provide material properties at different temperatures and phases for simulation, and phase transformation kinetic formulas are used to calculate the phase ratio changes of the material during welding, reflecting the evolution of the microstructure.

[0098] S1042: Import the planetary carrier geometry and mesh model from step S102 into the welding process simulation model.

[0099] In some embodiments, the geometric and mesh models serve as the spatial carrier for welding process simulation. Regional meshing can reasonably control the computational load of the base region while ensuring the calculation accuracy of the weld and heat-affected zone.

[0100] S1043: Import the welding process parameters and boundary conditions from step S103 into the welding process simulation model.

[0101] In some embodiments, process parameters such as welding speed, welding power, and welding time, as well as boundary conditions such as welding displacement constraints and air cooling rate, are imported into the simulation model. The process parameters determine the intensity and rhythm of the welding heat input, while the boundary conditions simulate the clamping and cooling environment of actual welding, together constructing a welding process scenario consistent with reality.

[0102] S1044: In the welding process simulation model, a 3D Gaussian heat source model is set up, and its heat flux density distribution is obtained using formula (3): Formula (3) The corresponding formula for heat flux radius is:

[0103] In the formula, Energy for 3D Gaussian body heat source and These are the z-coordinates of the upper and lower surfaces of the welding specimen, respectively. and The radius of heat flow distribution on the upper and lower surfaces.

[0104] In some embodiments, the heat source energy of electron beam welding exhibits a 3D Gaussian distribution. The formula can accurately describe the density changes of heat flow in the radial direction (r) and axial direction (z). The formula for the change of heat flow radius with z simulates the conical energy distribution characteristics of the heat source in electron beam welding.

[0105] S1045: Define welding traces in the welding process simulation model.

[0106] In some embodiments, the movement path of the welding heat source is defined in the simulation model, clarifying the movement sequence and position of the heat source on the planetary carrier geometry model. This ensures that the dynamic changes in heat input during welding match the actual welding path, making the simulation of material phase transformation and stress development time history more accurate, and supporting the reliability of residual stress and structural deformation information in subsequent data transmission.

[0107] In one embodiment of the present invention, based on step S105, the following is a possible embodiment and its specific implementation will be described in a non-limiting manner. S105 specifically includes the following steps: S1051: After the electron beam welding simulation of the planetary carrier is completed, export the microstructure evolution information of the material at the last time step of the process simulation and generate the material.inp file.

[0108] S1052: Export the residual stress distribution at the last time step of the process simulation to generate sigma.txt and hardini.txt files, generate the structural deformation to generate mesh.inp file, and generate the mesh node information to generate nodes.inp file.

[0109] S1053: Open the general mesh model processing software, import the mesh.inp file, and delete the BAR elements, SHELL elements, and property attributes in the file.

[0110] S1054: In the general mesh model processing software, create element sets for the front planetary carrier and the output shaft respectively, and delete the 'ELSET=' element set definition part in the ELEMENT line; at the same time, create the contact surface / unpair relationship between each component, and place the relationship content at the end of the mesh.inp file.

[0111] S1055: Add the command line *include,input=mesh.inp to the material.inp file, and import the modified material.inp file into the general mesh model processing software; establish the constraint node set according to the assembly relationship between the front planetary carrier and the output shaft, and then add the command line *Element Output,directions=YES,position=CENTROIDALMISES.

[0112] In some embodiments, the microstructure evolution information is obtained by calculating the phase transformation results at different temperatures and times during the welding process using formulas (1) and (2). The information at the last time step represents the final microstructure state of the material after welding. Deriving this information can preserve the influence of the welding process on the microstructure of the material. The thermal stress and phase transformation stress caused by heat input and cooling during the welding process are ultimately retained in the structure as residual stress, accompanied by structural geometric deformation. Deriving these data can completely preserve the influence of the welding process on the mechanical and geometric state of the structure.

[0113] In general mesh model processing software, after importing the mesh.inp file, the software's element filtering function is used to locate and delete rod and shell elements. Then, the property attributes recorded in the file are deleted through the attribute management module. Creating element sets allows for independent control of different components in subsequent analyses. Deleting the ELSET= definition avoids syntax errors when the software reads the data. Placing contact surface relationships at the end of the file conforms to the reading rules of general finite element software, ensuring that contact relationships are correctly identified.

[0114] This embodiment opens the material.inp file and adds the command line *include,input=mesh.inp to the file header or after the material parameter definition to establish a connection between the material data and the mesh model. After importing the modified material.inp file, based on assembly features such as the front planetary carrier bearing mounting position and the output shaft spline connection position, corresponding nodes are selected to create a constraint node set. Finally, the command *Element Output, directions=YES, position=CENTROIDAL MISES is added to the software's output control module to set the element stress output parameters. This achieves the integration of material data and the mesh model, ensuring accurate extraction of key stress parameters during the analysis process and improving analysis efficiency and result reliability.

[0115] In one embodiment of the present invention, based on step S106, the following is a possible embodiment and its specific implementation will be described in a non-limiting manner. S106 specifically includes the following steps: Step S1061: Create a new analysis step in the general-purpose finite element analysis software and set it as a static general-purpose analysis step. Specifically, define the analysis step type as Static,General, enable the geometric nonlinearity option, set the time increment to a fixed value, and specify the total analysis step time.

[0116] Step S1062: Import the transferable data processed in step S105 into the analysis model. Specifically, use the *INCLUDE command to import the material.inp and mesh.inp files sequentially, ensuring that material properties, mesh data, and contact relationships are correctly loaded into the analysis model.

[0117] Step S1063: Set the boundary conditions for the rebalancing analysis. Specifically, based on the constraint state of the last time step of the welding process simulation, apply displacement constraints on the corresponding node set, fix the corresponding degrees of freedom, and eliminate the rigid body displacement of the model.

[0118] Step S1064: Perform rebalancing analysis calculations and monitor the solution process. Specifically, submit the analysis job, set the field output to request stress and displacement variables, monitor the solution convergence, and ensure the analysis is completed successfully.

[0119] Step S1065: Extract and compare the results to verify the accuracy of data transfer. Specifically, read the displacement and Mises stress distribution after rebalancing analysis from the results file and perform a quantitative comparative analysis with the corresponding results of the original welding simulation.

[0120] In some embodiments, processed mesh, material, and contact relationship data are imported into a new analysis model via a file inclusion mechanism to verify the integrity of element, node, and material properties. Rigid body motion is eliminated by applying appropriate constraints, bringing the model to a stable equilibrium state. The nonlinear equilibrium equations are solved using Newton-Raphson iteration to achieve force equilibrium. Displacement and stress data after rebalancing are extracted from the results file and quantitatively compared with the original welding simulation results. The maximum displacement and stress differences are calculated to quantitatively verify the accuracy of data transfer, providing a reliable guarantee for strength and fatigue analysis.

[0121] In one embodiment of the present invention, based on step S108, the following is a possible embodiment and its specific implementation will be described in a non-limiting manner. S108 specifically includes the following steps: S1081: In general finite element analysis software, set the contact relationship between the planetary gear shaft and the planetary carrier claw hole, define the contact type as frictional contact, and set the friction coefficient and contact stiffness parameters.

[0122] In some embodiments, the contact type is selected as surface-to-surface contact, where the outer surface of the planetary gear shaft is the contact surface and the inner surface of the planetary carrier claw bore is the target surface. The coefficient of friction is determined based on the bearing lubrication condition. The contact stiffness parameter is adjusted through trial and error to ensure that the contact does not penetrate and the calculation converges.

[0123] S1082: Set the connection between the single-claw planetary carrier model in the welding simulation stage and the remaining claw body of the front planetary carrier and the output shaft extension section supplemented in step S107 as a bonded connection, so that the displacement of the contact surface nodes is fully coordinated.

[0124] In some embodiments, the contact surfaces of the bonded connection are geometrically cleaned, and the contact surface nodes of the single-claw model and the supplementary structure are rigidly connected in the software using the bonded contact pair function, meaning that the node displacements are completely consistent. This ensures the continuous transmission of forces between the single-claw model and the supplementary structure, guaranteeing the consistency of the mechanical response of the complete model.

[0125] S1083: Create coupling elements at the planet carrier bearing support position, the planet gear shaft and planet gear contact area, and the planet carrier external spline position, respectively, and couple the translational or rotational degrees of freedom of all nodes in each region to a master node.

[0126] In some embodiments, at the bearing support location, an annular region node where the bearing inner ring contacts the planetary carrier is selected, and its radial (X, Y) and axial (Z) translational degrees of freedom are coupled. In the planetary gear shaft contact area, a cylindrical surface node where the outer circle of the pin contacts the planetary gear is selected, and its rotational degrees of freedom are coupled. At the external spline location, a spline tooth surface node is selected, and its rotational degrees of freedom are coupled. The main node for each region is selected as the geometric center node. This ensures the integrity of force and displacement transmission and improves the accuracy of boundary condition settings.

[0127] S1084: Apply radial translational freedom constraints to the coupled master nodes at the bearing support position, and apply rotational freedom constraints to the coupled master nodes at the external spline position, such as restricting rotation around the Z-axis.

[0128] In some embodiments, the coupled master nodes at the bearing support location restrict translation in the X and Y directions and provide radial constraint. Translation in the Z direction is retained, and slight axial float is allowed. The coupled master nodes at the external spline location restrict rotation about the Z-axis to prevent overall rotation, while retaining degrees of freedom in other directions. This ensures that the model does not undergo rigid body displacement under load, but only elastic deformation.

[0129] S1085: Based on the maximum torque condition during actual service of the planetary carrier, apply a corresponding torque load, such as the torque around the Z-axis, to the coupling master node of the planetary gear shaft and the planetary gear contact area.

[0130] In some embodiments, the concentrated torque is transmitted to the entire contact area through the coupling master node, simulating the torque load transmitted from the planetary gears to the planetary carrier via the pin shaft, which is consistent with the actual torque transmission path from the planetary gears to the planetary carrier during service. Ensuring that the load magnitude and application location are consistent with the actual stress ensures that the analysis results accurately reflect the service stress state of the planetary carrier.

[0131] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0132] like Figure 7 As shown, this application also provides an electronic device, including a display module 103, a memory 102, a processor 101, a communication module 104, and a computer program stored in the memory and executable on the processor 101. When the processor 101 executes the program, it implements the steps of the welded integrated planetary carrier strength and fatigue analysis method.

[0133] In embodiments of the present invention, electronic devices include, but are not limited to, laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. Electronic devices may also represent various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the embodiments described and / or claimed herein.

[0134] In this embodiment, processor 101 may be implemented using at least one of an application-specific integrated circuit, a programmable logic device, a field-programmable gate array, a processor, a controller, a microcontroller, a microprocessor, or an electronic unit designed to perform the functions described herein. In some cases, such an implementation may be implemented within a controller. For software implementation, implementations such as processes or functions may be implemented with separate software modules that allow the performance of at least one function or operation. Software code may be implemented by a software application (or program) written in any suitable programming language, and the software code may be stored in memory and executed by the controller.

[0135] The display module 103 is used to display information input by the user or information provided to the user. The display module 103 may include a display panel, which may be configured in the form of a liquid crystal display, an organic light-emitting diode, or the like.

[0136] The memory 102 can be used to store software programs and various data. The memory 102 may include high-speed random access memory, and may also include non-volatile memory, such as at least one disk storage device, flash memory device, or other volatile solid-state storage device.

[0137] The communication module 104 transmits radio signals to and / or receives radio signals from at least one of a base station, an external terminal, and a server. Such radio signals may include voice call signals, video call signals, or various types of data sent and / or received according to text and / or multimedia messages.

[0138] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method of weld-integrated planetary carrier strength and fatigue analysis, characterized by, The method comprises: S101: building a material performance parameter library containing temperature and phase dependence functions; S102: processing the geometry and mesh model of the welded planet carrier, simplifying the complete model into a single claw model, dividing the front planet carrier and output shaft into base body, heat affected zone and weld part, and setting different mesh sizes; S103: determining the process parameters and boundary conditions required for welding simulation; S104: establishing a welding process simulation model, which integrates the material performance parameter library, geometry and mesh model, process parameters and boundary conditions, and includes a welding heat source model and weld trace definition; S105: retrieving the microstructure evolution information, residual stress distribution, structural deformation and mesh node information at the last time step of the welding process simulation, and processing the information in a general mesh model processing software to generate transferable data; S106: verifying the accuracy of the transferable data through rebalancing analysis; S107: supplementing the single claw model, adding planet wheel pin shafts and perfecting the remaining parts of the front planet carrier and output shaft, and setting the mesh size of the supplemented parts; S108: setting the boundary conditions for strength and fatigue analysis according to the actual structure and load state of the planet carrier; S109: introducing the residual stress distribution, structural deformation and mesh node information into the strength and fatigue analysis model, applying constraints and loads, performing strength analysis, and then grouping the weld sub-models and using the Basquin formula to calculate fatigue life.

2. The method of evaluating the strength and fatigue of a weld of a welding planetary carrier according to claim 1, characterized by, S102 specifically comprises the following steps: Using geometric symmetry, a single claw of a five-claw planet carrier is selected as the analysis object to construct a 1 / 5 scale model; the non-welding associated redundant claw body and accessory connectors outside the symmetry plane are removed, and the geometric features of the welding area of the front planet carrier and the output shaft are retained; The front planet carrier and the output shaft are divided into base body part, heat affected zone part and weld part; the heat affected zone is determined according to the temperature influence range of the welding thermal cycle, and the weld part is based on the actual fusion width and reinforcement geometry parameters of the electron beam welded joint to extract a three-dimensional solid model, and the base body part is the remaining main structure of the front planet carrier and the output shaft after removing the heat affected zone and the weld; The weld part adopts high-precision volume mesh, and the mesh size is set to 0.5mm or less; the heat affected zone mesh size is set to 0.5-1mm; the base body part adopts coarse volume mesh, and the size value is 1-10mm; the mesh type is preferentially selected as hexahedral dominant or tetrahedral adaptive, balancing calculation accuracy and efficiency; Low-quality units are screened using a mesh quality evaluation algorithm; Low-quality units are corrected by mesh redivision and node adjustment to ensure that the overall quality of the mesh meets the simulation convergence requirements; The total number of units of the complete mesh model is counted, and the mesh of the non-critical area such as the base body is gradually simplified; the stress peak deviation under different mesh quantities is compared, and when the result deviation is <5%, the final mesh quantity is determined, and the total mesh quantity is controlled within 1 million.

3. The method of weld planetary carrier weld joint strength and fatigue evaluation of claim 1, wherein, S103 specifically comprises the following steps: The specific values of the welding process parameters are extracted from the welding process card or database; Based on the welding clamping state of the planet carrier, the displacement constraint boundary condition is defined; The temperature field boundary condition is set to simulate the air cooling process; Integrate the process parameters and boundary conditions into the simulation model input file; Check the rationality of the process parameters and boundary conditions by the parameter verification algorithm.

4. The method of weld planetary carrier weld joint strength and fatigue evaluation of claim 1, wherein, S104 specifically comprises the following steps: Import the planetary carrier material performance parameter library of step S101 into the welding process simulation model; Import the planetary carrier geometry and mesh model of step S102 into the welding process simulation model; Import the welding process parameters and boundary conditions of step S103 into the welding process simulation model; Set a 3D Gaussian heat source model in the welding process simulation model, and the heat flux density distribution is obtained by formula (3): Equation (3) The corresponding heat flux radius formula is wherein, is the 3D Gaussian body heat source energy, and are the z coordinates of the upper and lower surfaces of the weldment, respectively; and are the upper and lower surface heat flux distribution radii, respectively. Define the welding trace in the welding process simulation model.

5. The welded integrated planetary carrier strength and fatigue analysis method of claim 1, wherein, S105 specifically comprises the following steps: After the completion of the planetary carrier electron beam welding simulation, export the material organization evolution information at the last time step of the process simulation to generate the material.inp file; Export the residual stress distribution at the last time step of the process simulation to generate the sigma.txt file and the hardini.txt file, the structure deformation to generate the mesh.inp file, and the grid node information to generate the nodes.inp file; Open the general mesh model processing software, import the mesh.inp file, and delete the BAR elements, SHELL elements and property attributes in the file; In the general mesh model processing software, establish element sets for the front planetary carrier and the output shaft respectively, delete the 'ELSET=' element set definition part in the ELEMENT row, and establish the contact surface between the components / release the relationship, and place the relationship content at the end of the mesh.inp file; Add the command line *include, input=mesh.inp in the material.inp file, and import the modified material.inp file into the general mesh model processing software; according to the assembly relationship between the front planetary carrier and the output shaft, establish a constraint node set, and then add the command line *Element Output, directions=YES, position=CENTROIDALMISES.

6. The method of weld planetary carrier weld seam strength and fatigue evaluation of claim 1, wherein, S106 specifically comprises the following steps: Create a new analysis step in the general finite element analysis software and set it as a static general analysis step; Import the transferable data processed in step S105 into the analysis model; Set the boundary conditions for the rebalancing analysis; Perform the rebalancing analysis calculation and monitor the solution process; Extract and compare the analysis results to verify the accuracy of data transfer.

7. The method of weld planetary carrier weld seam strength and fatigue evaluation of claim 1, wherein, S107 specifically comprises the following steps: In the general mesh model processing software, import the processed single-claw planetary carrier geometry and mesh model for welding simulation; According to the actual assembly size of the planetary carrier and the load transfer requirement, establish a geometric model of the planet pin shaft, and the axis of the planet pin shaft is aligned with the hole axis of the single-claw planetary carrier; Based on the 1 / 5 structure of the single-claw planetary carrier and the five-claw planetary carrier, copy the single-claw model and distribute it according to the circumferential distribution rule to complete the geometry and mesh model of the remaining claw body structure of the front planetary carrier. According to the flange connection or spline connection between the planet carrier and the output shaft, the extension section of the output shaft not included in the single claw model is supplemented, and the geometry and mesh model of the connection section are supplemented; The grid size of the supplemented single claw model is set to 1-10 mm, the supplemented single claw model is integrated with the single claw model to form a complete integrated planet carrier model, and the total number of grids is controlled to be less than 1 million.

8. The method of weld planetary carrier weld seam strength and fatigue evaluation of claim 1, wherein, S108 specifically includes the following steps: In the general finite element analysis software, the contact relationship between the planet wheel shaft and the claw body hole of the planet carrier is set, the contact type is defined as friction contact, and the friction coefficient and contact stiffness parameters are set; The connection relationship between the single claw planet carrier model in the welding simulation stage and the remaining claw body of the front planet carrier and the extension section of the output shaft supplemented in step S107 is set as a binding connection, so that the node displacement of the contact surface is completely coordinated; Coupling units are created at the bearing support position of the planet carrier, the contact area of the planet wheel shaft and the planet wheel, and the outer spline position, and the translation or rotation degrees of freedom of all nodes in each area are coupled to a master node; The coupling master node at the bearing support position is subjected to a radial translation degree of freedom constraint, and the coupling master node at the outer spline position is subjected to a rotation degree of freedom constraint; According to the maximum torque working condition of the planet carrier during actual service, a corresponding torque load is applied to the coupling master node at the contact area of the planet wheel shaft and the planet wheel.

9. The method of weld planetary carrier weld seam strength and fatigue evaluation of claim 1, wherein, S109 specifically includes the following steps: In the general finite element analysis software, the residual stress distribution, structural deformation, and grid node information transmitted in step S105 are imported into the complete integrated planet carrier geometry and mesh model constructed in step S107, and data mapping is realized through node number matching; The imported residual stress distribution data is adjusted, and the residual stress components of each node are multiplied by 50%; The bearing support constraint, outer spline rotation constraint, and planet wheel shaft torque load are applied to the strength and fatigue analysis model to ensure that the action positions of the constraints and loads correspond to the model nodes; In the general finite element analysis software, the yield strength data of each element of the weld and heat affected zone submodel is extracted, and the submodel is divided into 10 element groups according to the numerical difference of the yield strength, and each group of elements is assigned the yield strength parameters of the corresponding area; Run the strength and fatigue analysis solver to calculate the Mises stress distribution of the model to complete the static strength analysis; Based on the stress amplitude results, the fatigue life of the weld and heat affected zone is calculated using the Basquin formula 4, and the minimum safety factor is output; Formula 4 wherein is the stress amplitude, , are material constants.

10. An electronic device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, The processor implements the steps of the welding integrated planet carrier strength and fatigue analysis method according to any one of claims 1 to 9 when executing the program.

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