Deformation control method and device for track welding of aero-engine support based on DIC

Abstract

The invention discloses a deformation control method and device for track welding of an aero-engine support based on a DIC. The deformation control method comprises the steps that an engine support finite element model is established; the engine support finite element model is formed by splicing a spherical joint model, a supporting rod model and a single-fork joint model. Welding simulation is conducted on the splicing positions for multiple times, an initial welding scheme is selected, and the initial welding scheme comprises the number of welding segments, the welding sequence and welding parameters; 3D-DIC measuring equipment is added in the process of carrying out a track welding test by adopting an initial welding scheme, and whole-process and whole-region three-dimensional strain data of a base metal sample and a welding seam sample in the welding process are obtained; dIC is adopted to measure strain data near a weld joint, comparison verification is conducted on the strain data and a simulation result of an initial welding scheme, precision optimization of a finite element model and calculation conditions is achieved through welding parameter verification of multiple reference points and multiple time periods, and the optimal welding scheme is obtained through finite element simulation.

Description

Technical Field

[0001] The invention relates to the field of welding residual stress and deformation control, and in particular to a deformation control method and device for trajectory welding of an aero-engine bracket based on DIC. Background Art

[0002] Helicopter turboshaft engine bracket refers to an important welded structural part used to install the engine and bear large static and dynamic loads. With the development of modern helicopters, the requirements for engine brackets are getting higher and higher. If there is a problem with the quality of the bracket, it will seriously affect the performance of the engine and even cause the failure of the entire helicopter system.

[0003] At present, there are still many problems in the production of helicopter engine brackets. First, due to the unreasonable design of welding sequence and welding parameters, there are problems such as large welding deformation and difficulty in post-welding correction, resulting in low production qualification rate and slow production progress. Secondly, due to the instability of manual work, the existing manual arc welding leads to problems such as poor welding quality and large welding deformation. The post-welding flame correction workload is large and the heating time is long, which increases the negative impact of flame correction on the microstructure and performance of the weld, and reduces the qualification rate of helicopter engine brackets. The rise of automated welding can solve these problems. The automated welding process is completed by robots, which reduces human interference and improves welding speed and efficiency. Nowadays, automated welding has been widely used in various industrial fields. Automatic welding technology is not only used in pipeline welding assembly in various complex environments, but also in various ship production and welding of various liquefied natural gas membrane storage tanks. Using automatic track welding instead of manual argon arc welding to complete the welding of engine brackets can reduce human interference and improve the finished product rate and qualification rate of engine brackets. However, there is no experience in the application of track welding on engine brackets, and the specific welding parameters and welding processes still need to be continuously tested and explored. Summary of the invention

[0004] The purpose of the present invention is to solve the technical problems existing in the prior art, and to propose a deformation control method and device for trajectory welding of an aero-engine bracket based on DIC, so as to reduce the test cost and shorten the test time.

[0005] To achieve the above object, the technical solution provided by the present invention is: a deformation control method for trajectory welding of an aeroengine bracket based on DIC, the deformation control method specifically comprising the following steps:

[0006] Step 1: Perform thermoelastic-plastic finite element analysis on the welding of the engine bracket based on ABAQUS software to establish a finite element model of the engine bracket; the finite element model of the engine bracket is composed of three parts: a spherical joint model, a support rod model, and a single fork joint model;

[0007] Step 2: Perform multiple welding simulations on the joint positions of the spherical joint model, the support rod model, and the single fork joint model, and select an initial welding scheme, which includes the number of welding segments, welding sequence, and welding parameters;

[0008] Step 3: Add 3D-DIC measurement equipment during the welding test using the initial welding plan to obtain 3D-DIC measurement strain data of the base material sample and the weld sample during welding;

[0009] Step 4: Based on the 3D-DIC measured strain data and the simulation results of the initial welding scheme, the strain values ​​of the welding structure measured by 3D-DIC in the simulation process and the test are compared to optimize the accuracy of the simulation process and correct the welding parameters to obtain the best welding scheme;

[0010] Step 5: Carry out production test according to the best welding plan.

[0011] Further, selecting the initial welding scheme in step 2 specifically includes the following steps:

[0012] After the finite element model is established, the temperature field and stress field generated by the full circle welding of the splicing position are simulated in the finite element model according to the three different preset welding parameters;

[0013] By comparing the post-welding temperature field, post-welding residual stress and deformation, the welding parameters of the track welding of the engine bracket with the smallest residual stress and deformation are analyzed;

[0014] Combined with the actual range of adjustable welding parameters available for trajectory welding, the temperature field and stress field generated by welding in the segmented welding of the splicing position are simulated in the finite element model;

[0015] By comparing the post-welding temperature field, post-welding residual stress and deformation, the number of welding segments and the welding sequence of the trajectory welding of the engine bracket with the smallest residual stress and deformation are analyzed.

[0016] Furthermore, the specific method for obtaining the 3D-DIC measurement strain data of the base material sample and the weld sample during the welding process in step 3 is: using the initial welding plan to perform a welding test on the welding position of the engine bracket, and using 3D-DIC measurement equipment to perform full-field, full-domain, and full-process strain measurement to obtain three-dimensional strain data of the entire welding process.

[0017] Furthermore, in step 4, the precision optimization of the simulation process is realized and the welding parameters are corrected to obtain the best welding scheme. The specific method is as follows: the strain data calculated by the finite element model using the initial welding scheme is verified with the three-dimensional strain data of the 3D-DIC measuring equipment, and the finite element model using the initial welding scheme is corrected in the whole field, the whole domain and the whole process.

[0018] Furthermore, the finite element model of the initial welding scheme is used to perform full-field, full-domain and full-process corrections, including multiple corrections of the simulation model with the welding time as the standard axis and any position of the engine bracket as the correction range, until the calculation results of the simulation model are infinitely close to the 3D-DIC measurement deformation results of the welding test.

[0019] The present invention also discloses a deformation control device for trajectory welding of an aeroengine bracket based on DIC, the device comprising: an establishment module: used to establish a finite element model of the engine bracket; the finite element model of the engine bracket is composed of three parts: a spherical joint model, a support rod model and a single fork joint model;

[0020] Simulation module: used to perform multiple welding simulations on the joint positions of the spherical joint model, the support rod model and the single fork joint model, and select the initial welding scheme, which includes the number of welding segments, welding sequence and welding parameters;

[0021] Measurement module: used to add 3D-DIC measurement equipment during the welding test using the initial welding plan to obtain 3D-DIC measurement data of the base material sample and the weld sample during the welding process;

[0022] Correction module: used to compare the strain values ​​near the weld measured by 3D-DIC in the simulation process with those in the test according to the 3D-DIC measurement data and the simulation results of the initial welding plan, optimize the accuracy of the simulation process and correct the welding parameters to obtain the best welding plan;

[0023] Production module: used to produce tests according to the best welding plan.

[0024] Furthermore, the simulation module selects the initial welding plan including the following steps:

[0025] After the finite element model is established, the temperature field and stress field generated by the full circle welding of the splicing position are simulated in the finite element model according to the three different preset welding parameters;

[0026] By comparing the post-welding temperature field, post-welding residual stress and deformation, the welding parameters of the track welding of the engine bracket with the smallest residual stress and deformation are analyzed;

[0027] Combined with the actual range of adjustable welding parameters available for trajectory welding, the temperature field and stress field generated by welding in the segmented welding of the splicing position are simulated in the finite element model;

[0028] By comparing the post-welding temperature field, post-welding residual stress and deformation, the number of welding segments and the welding sequence of the trajectory welding of the engine bracket with the smallest residual stress and deformation are analyzed.

[0029] Furthermore, the specific method for obtaining 3D-DIC measurement strain data of the base material sample and the weld sample during the welding process in the measurement module is: the welding position of the engine bracket is subjected to a welding test using the initial welding plan, and the 3D-DIC measurement equipment is used to perform full-field, full-domain, and full-process strain measurement to obtain three-dimensional strain data of the entire welding process.

[0030] Furthermore, the correction module realizes the precision optimization of the simulation process and corrects the welding parameters accordingly to obtain the best welding scheme. The specific method is: use the three-dimensional strain data of the 3D-DIC measuring equipment to verify the strain data calculated by the finite element model using the initial welding scheme, and correct the finite element model using the initial welding scheme in the whole field, the whole domain and the whole process.

[0031] Beneficial effects of the present invention:

[0032] 1. The present invention performs thermoelastic-plastic finite element analysis on the welding of the engine bracket based on ABAQUS software, verifies the trajectory welding model through welding experiments, and highlights the rationality and authenticity of the simulation model.

[0033] 2. The present invention further illustrates, through comparison of simulation analysis results, that three-stage segmented welding is superior to four-stage and single-pass continuous welding, and that the residual stress and deformation optimization of engine bracket welding is higher than other solutions, providing a strong theoretical basis for engine bracket welding.

[0034] 3. This patent preferably uses 3D-DIC to measure the real-time three-dimensional strain of the entire process and entire domain of the welded engine bracket, verifies the measurement results and simulation results, and guides and corrects the finite element simulation through the measurement results of the entire area and multiple time periods, thereby solving the inherent problems of inaccuracy and uncertainty of the simulation results to the greatest extent, improving the connection with the actual experiments, and providing favorable high-precision data support for subsequent process optimization.

[0035] 4. This study is close to actual engineering applications, providing theoretical guidance for the selection of welding parameters for similar parts and technical support for welding deformation control. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The drawings described herein are used to provide further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0037] Figure 1a It is a structural schematic diagram of the engine bracket model;

[0038] Figure 1b Extract virtual path diagram for engine bracket data;

[0039] Figure 2aIt is a schematic diagram of the welding sequence of three-stage segment welding;

[0040] Figure 2b It is a schematic diagram of the welding sequence of four-stage segment welding;

[0041] Figure 3 This is the comparison diagram of the axial residual stress of the first weld;

[0042] Figure 4 This is the comparison diagram of the axial strain of the first weld;

[0043] Figure 5 This is a comparison chart of finite element analysis and results. DETAILED DESCRIPTION

[0044] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it cannot be understood as a limitation on the scope of protection of the present invention.

[0045] Track welding not only improves welding efficiency, but also ensures welding quality. Track welding is not only simple to operate, but also has a high one-time welding pass rate and is not affected by human factors. It can make welding deformation more stable and improve product yield. At the same time, different welding sequences will lead to changes in residual stress and strain after welding. Reasonable welding sequence can effectively improve the generation of welding residual stress and deformation. Welding deformation is an inevitable phenomenon in the welding process. After the engine bracket is welded, it needs to be placed on a specific fixture to inspect the welding deformation to see if it meets the welding standards. Therefore, the prediction and control of welding deformation and residual stress changes generated by the welding process are very critical. Digital image correlation technology (DIC) is a multi-dimensional (2D or 3D, distinguished by hardware composition, measurement and data processing technology), full-process, non-contact optical measurement system for measuring the contour, displacement, vibration, and strain of its material object. When it is used in the welding process of helicopter engine brackets, the welding deformation can be measured in three dimensions throughout the entire process and area, which plays a greater role in controlling the deformation of the engine bracket. Welding numerical simulation has extremely high accuracy and reliability in the simulation of track welding. At the same time, 3D-DIC is applied to very small to large measurement areas, and its results can be bidirectionally adapted with finite element analysis software, and the results of the two can be quantitatively compared. The introduction of this method to measure deformation during welding is conducive to the accurate verification of simulation results, improves the accuracy of finite element analysis results, and increases the feasibility of the present invention. The present invention uses finite element software in combination with actual track welding experiments, and uses 3D-DIC equipment to perform full-process and full-area three-dimensional measurements of actual experiments, and fully verifies the measurement results and computer simulations. In a physical sense, the computer simulation model and calculation conditions are corrected to the maximum extent, and the effect of effectively improving the accuracy of computer simulation is achieved. The purpose of the invention is to guide the welding of actual engine brackets with high-precision finite element simulation results, reduce the cost of welding tests, and shorten the time of engine bracket welding production tests.

[0046] Example 1

[0047] The present invention discloses a deformation control method for trajectory welding of an aero engine bracket based on DIC, comprising the following steps:

[0048] Step 1: Use ABAQUS finite element software to establish the engine bracket finite element model:

[0049] like Figure 1a As shown, the finite element model of the engine bracket is composed of three parts: a spherical joint model, a support rod model and a single fork joint model; the splicing positions of the spherical joint model, the support rod model and the single fork joint model are the welding positions to be welded.

[0050] Step 2: Optimize welding sequence:

[0051] After the finite element model is established, three different welding parameters are set and compared based on experience. Specifically, ABAQUS software is used to numerically simulate the temperature field and stress field generated by the full circle welding of the engine bracket using three different welding parameters. Afterwards, by comparing the post-welding temperature field, post-welding residual stress and deformation, the most suitable trajectory welding parameters for the engine bracket are analyzed.

[0052] The temperature field and stress field generated by multi-segment welding of the engine bracket using the above-mentioned trajectory welding parameters are numerically simulated. During the simulation process, a sequential coupling method is used to first calculate and analyze the welding temperature field, and then the results are imported into the structural model to calculate the stress field. Since changing the welding sequence can change the welding residual stress and deformation, a reasonable welding sequence can further improve the welding stability and yield rate of the engine bracket. Therefore, by comparing the post-welding temperature field, post-welding residual stress and deformation, the most suitable number of segments for the engine bracket and the welding sequence under this number of segments are analyzed. The welding sequence is as follows: Figure 2a and Figure 2b As shown. The welding sequence here refers to the order in which one section is carried out first and which one is carried out later when multiple sections are completed at the same connection position. At the same time, there are three schemes for three-section segment welding according to the welding sequence. This patent prefers the segment welding sequence of 123.

[0053] Step 3: Introduce 3D-DIC to simulate the measurement and correction of track welding:

[0054] Conduct actual track welding tests. Use the welding parameters of step 2 and 3D-DIC equipment to measure welding deformation. Use the binocular vision high-resolution camera configured in the equipment to obtain full-field and full-domain three-dimensional graphic data of the base material and weld sample during welding in real time. Use DIC software to process the graphic data and obtain the full-process strain data of the base material and weld near the welding process. Compare and verify the DIC strain data with the strain data of finite element simulation, and use the DIC data as a benchmark to modify the finite element simulation model and calculation conditions to obtain the numerical simulation model and calculation conditions that are consistent with the actual situation.

[0055] Through multiple multi-parameter segmented welding tests, multiple comparisons and verifications were carried out using 3D-DIC measurement strain data and finite element simulation strain data, multiple corrections were made to the finite element model and its calculation conditions, and high-precision optimization of the finite element model and calculation conditions was obtained, which can be used to further guide actual welding tests.

[0056] Step 4: Guiding the actual welding test based on the modified finite element model:

[0057] Since the essence of track welding is TIG welding. Before welding, clean the weld surface of the engine bracket first, and then use spot welding to fix the position of the spherical boss, single fork boss and support rod. Then select a clamping ring suitable for the size of the engine bracket to clamp and seal the engine bracket, and align the tungsten needle with the weld position. Through the high-precision finite element model and calculation conditions optimized by DIC, analyze the optimal welding parameters and segmented welding plan, input the current, voltage and welding speed of the optimal plan on the equipment, and select argon as the shielding gas. Wait for the track welding equipment to work according to the set program and wait for the welding to be completed.

[0058] The present invention also discloses a deformation control device for track welding of an aircraft engine bracket based on DIC, comprising:

[0059] Building module: used to build the finite element model of the engine bracket; the finite element model of the engine bracket is composed of three parts: the ball joint model, the support rod model and the single fork joint model;

[0060] Simulation module: used to perform multiple welding simulations on the joint positions of the spherical joint model, the support rod model and the single fork joint model, and select the initial welding scheme, which includes the number of welding segments, welding sequence and welding parameters;

[0061] Measurement module: used to add 3D-DIC measurement equipment during the welding test using the initial welding plan to obtain 3D-DIC measurement data of the base material sample and the weld sample during the welding process;

[0062] Correction module: used to compare the strain values ​​near the weld measured by 3D-DIC in the simulation process with those in the test according to the 3D-DIC measurement data and the simulation results of the initial welding plan, optimize the accuracy of the simulation process and correct the welding parameters to obtain the best welding plan;

[0063] Production module: used to produce tests according to the best welding plan.

[0064] Furthermore, the simulation module selects the initial welding plan including the following steps:

[0065] After the finite element model is established, the temperature field and stress field generated by the full circle welding of the splicing position are simulated in the finite element model according to the three different preset welding parameters;

[0066] By comparing the post-welding temperature field, post-welding residual stress and deformation, the trajectory welding parameters of the engine bracket with the smallest residual stress and deformation are analyzed;

[0067] Combined with the actual available adjustable welding parameter range of trajectory welding, the temperature field and stress field generated by segmented welding at the splicing position are simulated in the finite element model;

[0068] By comparing the post-welding temperature field, post-welding residual stress and deformation, the number of welding segments and the welding sequence of the trajectory welding of the engine bracket with the smallest residual stress and deformation are analyzed.

[0069] Furthermore, the specific method for obtaining 3D-DIC measurement strain data of the base material sample and the weld sample during the welding process in the measurement module is: the welding position of the engine bracket is subjected to a welding test using the initial welding plan, and the 3D-DIC measurement equipment is used to perform full-field, full-domain, and full-process strain measurement to obtain three-dimensional strain data of the entire welding process.

[0070] Furthermore, the correction module realizes the precision optimization of the simulation process and corrects the welding parameters accordingly to obtain the best welding scheme. The specific method is: use the three-dimensional strain data of the 3D-DIC measuring equipment to verify the strain data calculated by the finite element model using the initial welding scheme, and correct the finite element model using the initial welding scheme in the whole field, the whole domain and the whole process.

[0071] In order to verify the effectiveness and accuracy of the finite element simulation to guide the actual trajectory welding test, an X-ray stress tester was used to measure the residual stress on the weld surface of the engine bracket. Figure 5 As shown in the figure, the finite element results are in good agreement with the measured results, and the residual stress trends of the two are consistent. There is a certain error between the experimental data and the numerical prediction values. This is caused by the inherent fluctuation of the welding results and the measurement error of the X-ray diffractometer. The average error between the measured values ​​and the simulation values ​​at the six points is 8.9%, which is within a reasonable range.

[0072] Example 2

[0073] The present invention provides a track welding method for an engine bracket based on single-pass continuous welding:

[0074] Step 1: Use ABAQUS software to simulate the temperature field and stress field generated by the engine bracket using a full-circle single-pass continuous welding. Then, by comparing the post-welding temperature field, post-welding residual stress and deformation, the most suitable welding parameters for the track welding of the engine bracket are analyzed.

[0075] Step 2: Use acetone to wipe the surface of the two welding joints in a circle to clean the surface dirt around the welding joints.

[0076] Step three: There is no need to bend the weld. Just align the spherical boss, single-pronged boss and support rod at the welding joint. Use spot welding to fix the position of each joint at three points.

[0077] Step 4: Install the fixed engine bracket onto the special welding fixture, which completely fixes the ball joint and the single fork joint.

[0078] Step 5: Select a track welding fixture with a radius of 10 mm, clamp it at the first weld, and align the tungsten needle with the weld.

[0079] Step six: Install the 3D-DIC measurement equipment near the welding equipment to collect the real-time strain change values ​​during the welding process.

[0080] Step 7: Set the welding voltage to 10V, the current to 80A and the welding speed to 1mm / s on the track welding equipment. Then start the welding equipment and work according to the preset program, and wait for the welding to be completed.

[0081] Step 8. After all welding is completed, remove the engine bracket from the special fixture.

[0082] Step nine, in the subsequent weld samples, replace another set of preferred parameters and repeat steps three to six. For the above multiple tests, the strain data measured by 3D-DIC and the strain data of finite element simulation are compared and verified to achieve multiple corrections of the finite element model and its calculation conditions, and obtain high-precision optimization of the finite element model and calculation conditions. At the same time, through the optimization calculation of finite element simulation, the optimal single weld welding parameters are further screened and determined as welding voltage 10V, current 80A and welding speed 1.5mm / s, which are used to further guide actual welding tests.

[0083] Example 3

[0084] The present invention provides a track welding method for an engine bracket based on segmented welding:

[0085] Step 1: Use ABAQUS software to simulate the temperature field and stress field generated by the multi-stage welding test of the engine bracket. Then, by comparing the post-welding temperature field, post-welding residual stress and deformation, the most suitable trajectory welding parameters for the engine bracket are analyzed.

[0086] Step 2: Use acetone to wipe the surface of the two welding joints in a circle to clean the surface dirt around the welds.

[0087] Step three: There is no need to groove the weld. Just align the spherical boss, single-fork boss and support rod at the weld. Use spot welding to fix the position of each weld at three points.

[0088] Step 4: Install the fixed engine bracket onto the special welding fixture, which completely fixes the ball joint and the single fork joint.

[0089] Step 5: Select a track welding fixture with a radius of 10 mm, clamp it at the first weld, and align the tungsten needle with the weld.

[0090] Step six: Install the 3D-DIC measurement equipment near the welding equipment to collect the real-time strain change values ​​during the welding process.

[0091] Step 7: Set the voltage to 10V, the current to 80A and the welding speed to 1.5mm / s on the track welding equipment. Then start the welding equipment and wait for the welding to be completed.

[0092] Step 8. After all welding is completed, remove the engine bracket from the special fixture.

[0093] Step 9: In subsequent weld samples, by changing the welding sequence, repeating steps 3 to 6, two welding methods of three-stage and four-stage are realized, such as Figure 2a and Figure 2b For the above multiple tests, the strain data measured by 3D-DIC equipment and the strain data of finite element simulation were compared and verified to achieve multiple corrections of the finite element model and its calculation conditions, and obtain high-precision optimization of the finite element model and calculation conditions.

[0094] Use the optimized finite element simulation method to conduct segmented welding tests to find the best welding solution. Figure 1b As shown, a virtual path L1 perpendicular to the two welds is established on the finite element model grid of the engine bracket to extract stress and strain data in the axial direction. The path L1 passes through the midpoint of the third section of the three-section segment weld and the starting point of the second section of the four-section segment weld.

[0095] The determined optimal single weld parameters are used to simulate segmented welding. Figure 3 , Figure 4 As shown in Table 1, Table 1 shows the displacement size of the measurement points.

[0096] Table 1

[0097]

[0098] From the simulation results of single-pass continuous welding, it can be seen that the peak axial stress at the support rod of the first weld is 58.5MPa, and the peak axial stress at the spherical joint is 164MPa. The axial strain at the starting point of the first weld is 0.022. The displacement of the center point of the upper surface of the single fork joint in the X direction is 0.185mm, the displacement in the Y direction is 0.029mm, and the displacement in the Z direction is 0.232mm.

[0099] From the simulation results of three-stage segmented welding, it can be seen that the peak axial stress at the support rod of the first weld is 34.7MPa, and the peak axial stress at the spherical joint is 110MPa. The axial strain at the starting point of the first weld is 0.012. The displacement of the center point of the upper surface of the single fork joint in the X direction is 0.068mm, the displacement in the Y direction is 0.043mm, and the displacement in the Z direction is 0.232mm.

[0100] From the simulation results of the four-stage segmented welding, it can be seen that the peak axial stress at the support rod of the first weld is 46.1MPa, and the peak axial stress at the spherical joint is 128.3MPa. The axial strain at the starting point of the first weld is 0.025. The displacement of the center point of the upper surface of the single fork joint in the X direction is 0.111mm, the displacement in the Y direction is 0.119mm, and the displacement in the Z direction is 0.225mm.

[0101] From the above numerical simulation results, it can be seen that the peak axial stress of the three-stage segmented welding at the first weld support rod is reduced by 24.7% compared with the four-stage segmented welding, and the peak axial stress of the three-stage segmented welding is reduced by 40.6% compared with the single-pass continuous welding; at the first weld spherical joint, the peak axial stress of the three-stage segmented welding is reduced by 14.3% compared with the four-stage segmented welding, and the peak axial stress of the three-stage segmented welding is reduced by 32.9% compared with the single-pass continuous welding; the peak axial stress of the first weld is reduced by 24.7% compared with the four-stage segmented welding, and the peak axial stress of the three-stage segmented welding is reduced by 40.6% compared with the single-pass continuous welding; The axial strain of the three-stage segmented welding at the point is reduced by 52% compared with the four-stage segmented welding, and the axial strain of the three-stage segmented welding is reduced by 45.5% compared with the single-pass continuous welding; in the X direction, the displacement of the three-stage segmented welding is reduced by 38.7% compared with the four-stage segmented welding, and the displacement of the three-stage segmented welding is reduced by 63.2% compared with the single-pass continuous welding. In the Y direction, the displacement of the three-stage segmented welding is reduced by 63.8% compared with the four-stage segmented welding, and the displacement of the three-stage segmented welding is increased by 32.6% compared with the single-pass continuous welding. In the Z direction, the displacement of the three schemes is not much different.

[0102] Therefore, finite element simulation screened and determined the best welding scheme as a three-stage jump welding form, with a welding voltage of 10 V, a current of 80 A, and a welding speed of 1.5 mm / s. The best welding scheme will guide the actual welding test.

[0103] In summary, the present invention performs thermo-elastoplastic finite element analysis on the welding of the engine bracket based on ABAQUS software, verifies the trajectory welding simulation model through welding experiments coordinated with 3D-DIC, and highlights the rationality and authenticity of the simulation model.

[0104] Secondly, this patent preferably uses 3D-DIC to measure the real-time three-dimensional strain of the entire process and entire domain of the welded engine bracket, verifies the measurement results and simulation results, and guides and corrects the finite element simulation through the measurement results of the entire area and multiple time periods, thereby solving the inherent problems of inaccuracy and uncertainty of the simulation results to the greatest extent, improving the connection with actual experiments, and providing favorable high-precision data support for subsequent process optimization.

[0105] In addition, the present invention selects the optimal welding parameters through two-way comparison of simulation analysis and test results, and further illustrates that three-stage segmented welding is better than four-stage and single-pass continuous welding. The residual stress and deformation optimization of aero-engine bracket welding is higher than other schemes, providing a strong theoretical basis for aero-engine bracket welding.

[0106] Finally, this study is close to actual engineering applications, providing theoretical guidance for the selection of welding parameters for similar parts and technical support for welding deformation control.

[0107] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes and modifications may be made to the embodiments without departing from the principles of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A deformation control method for track welding of an aircraft engine bracket based on DIC, characterized in that: The deformation control method specifically comprises the following steps: Step 1: Perform thermoelastic-plastic finite element analysis on the welding of the engine bracket based on ABAQUS software to establish a finite element model of the engine bracket; the finite element model of the engine bracket is composed of three parts: a spherical joint model, a support rod model, and a single fork joint model; Step 2: Perform multiple welding simulations on the joint positions of the spherical joint model, the support rod model, and the single fork joint model, and select an initial welding scheme, which includes the number of welding segments, welding sequence, and welding parameters; Step 3: Add 3D-DIC measurement equipment during the welding test using the initial welding plan to obtain 3D-DIC measurement strain data of the base material sample and the weld sample during welding; Step 4: Based on the 3D-DIC measured strain data and the simulation results of the initial welding scheme, the strain values ​​of the welding structure measured by 3D-DIC in the simulation process and the test are compared to optimize the accuracy of the simulation process and correct the welding parameters to obtain the best welding scheme; Step 5: Carry out production test according to the best welding plan.

2. According to claim 1, a deformation control method for trajectory welding of an aircraft engine bracket based on DIC is characterized in that: The initial welding scheme selected in step 2 specifically includes the following steps: After the finite element model is established, the temperature field and stress field generated by the full circle welding of the splicing position are simulated in the finite element model according to the three different preset welding parameters; By comparing the post-welding temperature field, post-welding residual stress and deformation, the welding parameters of the track welding of the engine bracket with the smallest residual stress and deformation are analyzed; Combined with the actual range of adjustable welding parameters available for trajectory welding, the temperature field and stress field generated by welding in the segmented welding of the splicing position are simulated in the finite element model; By comparing the post-welding temperature field, post-welding residual stress and deformation, the number of welding segments and the welding sequence of the trajectory welding of the engine bracket with the smallest residual stress and deformation are analyzed.

3. The deformation control method of the DIC-based trajectory welding of an aircraft engine bracket according to claim 1 is characterized in that: The specific method for obtaining the 3D-DIC measurement strain data of the base material sample and the weld sample during the welding process in step 3 is: using the initial welding plan to conduct a welding test on the welding position of the engine bracket, and using 3D-DIC measurement equipment to perform full-field, full-domain, and full-process strain measurement to obtain three-dimensional strain data of the entire welding process.

4. The deformation control method of the DIC-based trajectory welding of an aircraft engine bracket according to claim 1 is characterized in that: The specific method for optimizing the accuracy of the simulation process in step 4 and correcting the welding parameters to obtain the best welding solution is as follows: using the three-dimensional strain data of the 3D-DIC measuring equipment to verify the strain data calculated by the finite element model using the initial welding solution, and correcting the finite element model using the initial welding solution in the entire field, the entire domain, and the entire process.

5. The deformation control method of the DIC-based trajectory welding of an aircraft engine bracket according to claim 4 is characterized in that: The finite element model of the initial welding scheme is used for full-field, full-domain and full-process correction, including multiple corrections of the simulation model with welding time as the reference axis and any position of the engine bracket as the correction range, until the calculation results of the simulation model are infinitely close to the 3D-DIC measurement deformation results of the welding test.

6. A deformation control device for track welding of aircraft engine bracket based on DIC, characterized in that: The device comprises: a building module: used for building a finite element model of the engine bracket; the finite element model of the engine bracket is composed of three parts: a spherical joint model, a support rod model and a single fork joint model; Simulation module: used to perform multiple welding simulations on the joint positions of the spherical joint model, the support rod model and the single fork joint model, and select the initial welding scheme, which includes the number of welding segments, welding sequence and welding parameters; Measurement module: used to add 3D-DIC measurement equipment during the welding test using the initial welding plan to obtain 3D-DIC measurement data of the base material sample and the weld sample during the welding process; Correction module: used to compare the strain values ​​near the weld measured by 3D-DIC in the simulation process with those in the test according to the 3D-DIC measurement data and the simulation results of the initial welding plan, optimize the accuracy of the simulation process and correct the welding parameters to obtain the best welding plan; Production module: used to produce tests according to the best welding plan.

7. The deformation control device for track welding of an aircraft engine bracket based on DIC according to claim 6 is characterized in that: The simulation module selects the initial welding plan, which specifically includes the following steps: After the finite element model is established, the temperature field and stress field generated by the full circle welding of the splicing position are simulated in the finite element model according to the three different preset welding parameters; By comparing the post-welding temperature field, post-welding residual stress and deformation, the welding parameters of the track welding of the engine bracket with the minimum residual stress and deformation are analyzed; Combined with the actual range of adjustable welding parameters available for trajectory welding, the temperature field and stress field generated by welding in the segmented welding of the splicing position are simulated in the finite element model; By comparing the post-welding temperature field, post-welding residual stress and deformation, the number of welding segments and the welding sequence of the trajectory welding of the engine bracket with the smallest residual stress and deformation are analyzed.

8. The deformation control device for track welding of an aircraft engine bracket based on DIC according to claim 6 is characterized in that: The specific method for obtaining 3D-DIC measurement strain data of the base material sample and the weld sample during welding in the measurement module is as follows: the welding position of the engine bracket is subjected to a welding test using the initial welding plan, and 3D-DIC measurement equipment is used to perform full-field, full-domain, and full-process strain measurement to obtain three-dimensional strain data of the entire welding process.

9. The deformation control device for track welding of an aircraft engine bracket based on DIC according to claim 6, characterized in that: The specific method for optimizing the accuracy of the simulation process in the correction module and correcting the welding parameters to obtain the best welding scheme is: using the three-dimensional strain data of the 3D-DIC measuring equipment to verify the strain data calculated by the finite element model using the initial welding scheme, and correcting the finite element model using the initial welding scheme in the entire field, the entire domain, and the entire process.

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