A method to improve the accuracy of welding deformation simulation

Abstract

This invention discloses a method for improving the accuracy of welding deformation simulation. The method includes the following steps: acquiring multiple digital models of parts to be welded, pre-meshed according to preset requirements; defining welding nodes between the multiple digital models using a pin-hole fit method to reduce positioning errors caused by welding deformation; acquiring limit parameters containing clearance amounts to limit the multiple digital models of parts, thereby incorporating the actual clearance amounts of the parts into the limits of the simulated welding, improving both the limit accuracy and the accuracy of the simulated welding. After improving the positioning and limit accuracy, by acquiring input simulated welding information and performing simulated welding based on this information, the accuracy of the final simulated welding digital model is significantly improved.

Description

Technical Field

[0001] This invention relates to the field of simulation welding technology, and in particular to a method for improving the accuracy of welding deformation simulation. Background Technology

[0002] In the automotive manufacturing industry, welding deformation is common in resistance spot welding and arc welding. Welding deformation affects the precision of products, and the control measures for welding deformation in actual objects are not very effective. Therefore, the simulation of welding deformation helps to analyze the principles and control measures of deformation.

[0003] Simufact is a mainstream welding deformation simulation software that can analyze welding deformation results for resistance spot welding and arc welding. Based on elastoplastic theory, it can perform coupled analysis of thermo-mechanical-phase transformation, resulting in simulation results that are closer to the actual object.

[0004] However, there are virtually no reference cases for the Simufact simulation analysis method on the market, especially regarding measures to improve accuracy, for which there is very little information. The Simufact simulation software itself defines the basic simulation steps and settings for resistance spot welding and arc welding. However, these steps and methods are only some basic conditions for obtaining results. Due to the differences between the physical object and the simulation, the accuracy of the simulation is actually different from that of the physical object. Summary of the Invention

[0005] The main objective of this invention is to propose a method to improve the accuracy of welding deformation simulation, thereby enhancing the precision of simulated welding.

[0006] To achieve the above objectives, the present invention proposes a method for improving the accuracy of welding deformation simulation, comprising the following steps:

[0007] Obtain digital models of multiple parts to be welded together, which have been meshed according to preset requirements;

[0008] Welding joints between multiple part models are defined using a pin-hole mating method.

[0009] Obtain limit parameters containing the clearance amount and use them to limit the positions of multiple digital models of the parts.

[0010] Obtain the input simulation welding information, and perform simulation welding based on the simulation welding information.

[0011] Optionally, in the step of obtaining the digital model of multiple welded connections that have been meshed according to preset requirements:

[0012] The digital models of the multiple parts to be welded together are meshed using a hexahedral mesh.

[0013] Optionally, the thickness of the hexahedral mesh is set to h, the length to L, and the width to w, where:

[0014] 0 < h / L ≤ 1 / 5; and / or, 0.7 ≤ L / w ≤ 1.5.

[0015] Optionally, among the digital models of multiple welded parts, the interference amount between adjacent two digital models of parts is less than 0.02 mm.

[0016] Optionally, in the step of defining the welding joints between multiple digital models of parts by using the pin-hole fitting method:

[0017] Set the gap between the outer wall surface of the positioning pin and the inner wall surface of the positioning hole as I, where 0.03 mm ≤ I ≤ 0.05 mm.

[0018] Optionally, on the digital model of the part provided with the positioning hole, multiple grids surrounding the periphery of the positioning hole are arranged in a gradually denser manner along the direction from the edge to the middle of the positioning hole.

[0019] Optionally, the limiting parameter containing the clearance amount includes the clearance amount value between the actually to-be-welded part and the limiting component.

[0020] Optionally, the simulation welding information includes at least one of welding sequence, welding trajectory, welding parameters, electrothermal coupling coefficient, welding tong clamping force, chuck clamping force, and part material.

[0021] Optionally, the simulation welding information includes welding parameters and electrothermal coupling coefficient;

[0022] The steps of obtaining the input simulation welding information and performing simulation welding according to the simulation welding information include:

[0023] Obtain the penetration depth of the actually welded part input, query the first mapping relationship to determine the welding parameters, and query the second mapping relationship to determine the electrothermal coupling coefficient, where the first mapping relationship is the correlation relationship between the penetration depth of the welded part and the welding parameters, and the second mapping relationship is the correlation relationship between the penetration depth of the welded part and the electrothermal coupling coefficient;

[0024] Perform simulation welding according to the welding parameters and electrothermal coupling coefficient.

[0025] Optionally, after the steps of obtaining the input simulation welding information and performing simulation welding according to the simulation welding information, it further includes:

[0026] Adjust the simulation reference point so that the position of the simulation reference point is consistent with the fixture reference point to obtain the total welding deformation amount;

[0027] The total welding deformation is decomposed along the X-axis, Y-axis and Z-axis respectively, and the deformation along the three axes is displayed in the form of cloud diagrams and measurement points.

[0028] In the aforementioned method for improving the accuracy of welding deformation simulation, multiple part models to be welded and connected are obtained, meshed according to preset requirements. Welding nodes between these part models are defined using a pin-hole fit method to reduce positioning errors caused by welding deformation. Limiting parameters containing clearance amounts are obtained to limit the multiple part models, thus incorporating the actual clearance amounts of the parts into the simulated welding limits, improving both the limiting accuracy and the accuracy of the simulated welding. After improving the positioning and limiting accuracy, input simulation welding information is obtained, and simulation welding is performed based on this information, thereby significantly improving the accuracy of the final simulated welding part models. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0030] Figure 1 A flowchart illustrating an embodiment of the method for improving the simulation accuracy of welding deformation provided by the present invention;

[0031] Figure 2 A top view of part of the structure after the digital model of the part has been meshed;

[0032] Figure 3 A front view schematic diagram of a portion of the structure after the digital model of the part has been meshed;

[0033] Figure 4 This is a schematic diagram of the structure after inputting the clearance between parts during simulated welding.

[0034] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0035] 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 a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0036] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0037] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0038] In the automotive manufacturing industry, welding deformation is common in resistance spot welding and arc welding. Welding deformation affects the precision of products, and the control measures for welding deformation in actual objects are not very effective. Therefore, the simulation of welding deformation helps to analyze the principles and control measures of deformation.

[0039] Simufact is a mainstream welding deformation simulation software that can analyze welding deformation results for resistance spot welding and arc welding. Based on elastoplastic theory, it can perform coupled analysis of thermo-mechanical-phase transformation, resulting in simulation results that are closer to the actual object.

[0040] However, there are virtually no reference cases for the Simufact simulation analysis method on the market, especially regarding measures to improve accuracy, for which there is very little information. The Simufact simulation software itself defines the basic simulation steps and settings for resistance spot welding and arc welding. However, these steps and methods are only some basic conditions for obtaining results. Due to the differences between the physical object and the simulation, the accuracy of the simulation is actually different from that of the physical object.

[0041] This invention provides a method for improving the accuracy of welding deformation simulation, wherein, Figures 1 to 4 The present invention provides a flowchart and a corresponding structural diagram of the method for improving the simulation accuracy of welding deformation.

[0042] Please see Figure 1 The methods to improve the accuracy of welding deformation simulation include the following steps:

[0043] Step S10: Obtain the digital models of multiple parts to be welded that have been meshed according to preset requirements;

[0044] Step S20: Define the welding nodes between multiple digital models of parts by using pin-hole fitting;

[0045] Step S30: Obtain the limit parameters including the clearance amount to limit multiple digital models of the parts;

[0046] Step S40: Obtain the input simulation welding information and perform simulation welding according to the simulation welding information.

[0047] In the above method for improving the simulation accuracy of welding deformation, obtain the digital models of multiple parts to be welded that have been meshed according to preset requirements, define the welding nodes between multiple digital models of parts by using pin-hole fitting, reduce the positioning error caused by welding deformation, obtain the limit parameters including the clearance amount to limit multiple digital models of the parts, and realize bringing the clearance amount of the actual parts into the limit of the simulation welding, so as to improve the limit accuracy and the simulation welding accuracy. After improving the positioning accuracy and the limit accuracy, by obtaining the input simulation welding information and performing simulation welding according to the simulation welding information, the accuracy of the digital model of the parts finally completed with simulation welding is greatly improved.

[0048] Specifically, in the step of step S10 of obtaining the digital models of multiple welded parts that have been meshed according to preset requirements:

[0049] Refer to Figure 2 , the digital models of multiple parts to be welded are meshed with hexahedron meshes. In this way, when the mesh is a hexahedron, the smaller the mesh size, the higher the calculation accuracy, and the simulation accuracy and convergence are improved.

[0050] Specifically, set the thickness of the hexahedron mesh as h, the length as L, and the width as w, where 0 < h / L ≤ 1 / 5; and / or, 0.7 ≤ L / w ≤ 1.5. In this way, the size of the mesh is within a suitable range, thereby improving the accuracy of the simulation welding.

[0051] It should be noted that the thickness of most automotive panel parts is 0.6 - 3.0 mm, the ratio of the mesh thickness to the width ≤ 1 / 5, the ratio of the thickness to the length ≤ 1 / 5, the length (4 - 6) and the width (4 - 6), and the ratio of the length to the width is 0.7 - 1.5, and the overall mesh size is 5 mm.

[0052] Specifically, by making the interference amount between adjacent two digital models of parts in multiple digital models of the welded parts less than 0.02 mm, in this way, errors are avoided during subsequent simulation welding.

[0053] To improve the welding accuracy, refer to Figure 2On the part model with the positioning hole, multiple grids surrounding the positioning hole are arranged in a gradually denser pattern from the edge of the positioning hole to the center.

[0054] Specifically, in step S20, which describes defining the welding nodes between multiple part digital models using a pin-hole fit method, refer to... Figure 3 The gap between the outer wall of the locating pin and the inner wall of the locating hole is set as I, where 0.03mm≤I≤0.05mm.

[0055] It should be noted that, in order to improve simulation accuracy, it is recommended to refine the mesh size to 1mm within 5mm of the locating pin, weld and weld point, and gradually transition the mesh size to 5mm within 5-20mm.

[0056] In simulated welding, the limiting position is equivalent to the support and clamping blocks of the physical fixture. Existing simulation methods all use a method where the support and clamping are completely in contact with the part. However, in reality, some supports and some clamping blocks are not in contact with the part, resulting in a discrepancy between the simulation and the actual work. Specifically, in step S30, which involves obtaining limiting parameters containing the amount of clearance to limit multiple digital models of the parts, the limiting parameters containing the amount of clearance between the actual part to be welded and the limiting assembly include the value of the clearance between the part and the limiting assembly. This ensures that the simulated limiting position matches the actual limiting position, thereby improving welding accuracy.

[0057] It should be noted that, therefore, it is necessary to extract the clearance between the physical object and the limit and substitute it into the simulation. Also, since the first step of the Simufact simulation is to perform contact calculation, if non-contact is determined, the next step of the calculation will not be able to identify it. Therefore, a moving-clamping scheme is introduced, that is, at 0 seconds of simulation, the support is in contact with the part, and at 0.1 seconds of simulation, the support moves away from the part, and the clearance is consistent with the physical object.

[0058] Typical welding deformation simulations do not take into account the overlap gap between parts, only simulating the effects of thermo-mechanical-phase transitions. Because the overlap gap differs from reality, the simulation's trend and accuracy will be inconsistent with the actual situation. Therefore, it is necessary to modify the mesh shape in the simulation to match or closely approximate the actual object. Figure 4 As shown: Based on the actual physical investigation, the overlap of the longitudinal beam assembly is set with some gradually varying overlap gaps in the simulation model. The overlap gap is denoted as dl, where dl = 0.2mm. Of course, in other embodiments, the overlap gap can be set as needed, and this application does not limit it in this regard.

[0059] Step S40 involves acquiring the input simulation welding information and performing simulation welding based on this information. The simulation welding information includes at least one of the following: welding sequence, welding trajectory, welding parameters, electrothermal coupling coefficient, welding clamp clamping force, chuck clamping force, and part material. Of course, in other embodiments, the simulation welding information can be selected as needed, and this application does not limit this selection.

[0060] It should be noted that the welding parameters mentioned include pre-compression time, welding time, welding current, segmented welding time, and holding time.

[0061] Further, the simulated welding information includes welding parameters and electrothermal coupling coefficient. Step S40 involves acquiring the input simulated welding information and performing simulated welding based on the simulated welding information, including:

[0062] Step S401: Obtain the actual weld penetration of the input welded part, query the first mapping relationship to determine the welding parameters, and query the second mapping relationship to determine the electrothermal coupling coefficient. The first mapping relationship is the correlation between the weld penetration of the welded part and the welding parameters, and the second mapping relationship is the correlation between the weld penetration of the welded part and the electrothermal coupling coefficient.

[0063] Step S402: Perform simulated welding based on the welding parameters and electrothermal coupling coefficient.

[0064] In the above steps, the weld penetration depth of the actual welded part is obtained, a first mapping relationship is queried to determine the welding parameters, and a second mapping relationship is queried to determine the electrothermal coupling coefficient. The first mapping relationship is the correlation between the weld penetration depth of the welded part and the welding parameters, and the second mapping relationship is the correlation between the weld penetration depth of the welded part and the electrothermal coupling coefficient. Simulated welding is performed based on the welding parameters and the electrothermal coupling coefficient, ensuring that the simulated welding parameters and electrothermal coupling coefficient are consistent with the actual welding parameters and electrothermal coupling coefficient in the actual welding process. This improves the accuracy of the simulated welding and facilitates the subsequent analysis of the simulated welding results to derive the relevant parameters for the actual welding.

[0065] Furthermore, after step S40, the step of obtaining the input simulation welding information and performing simulation welding based on the simulation welding information, the method further includes:

[0066] Step S50: Adjust the simulation reference point so that the position of the simulation reference point is consistent with the fixture reference point, so as to obtain the total welding deformation.

[0067] It's important to note that welding deformation simulation results typically display the final deformation around one or more reference points. This result could be due to changes in the part's shape or rotation of the entire part. Conventional simulation analysis involves engineers setting reference points in areas they believe will not deform, then obtaining simulation results. However, without physical samples or empirical references, these reference points themselves may be deformable. Setting the reference points in these locations would cause overall part rotation, distorting the analysis results. To avoid this, a rule needs to be defined for setting the reference points: the simulation's reference points must be consistent with the GD&T (dimensional and tolerance) drawings. This is because the reference points for the physical part's precision inspection are consistent with the GD&T drawings; setting them in the same way for the simulation ensures consistency between the two references, allowing for direct comparison of results. When gravity is enabled in the simulation, the part falls freely onto the various references. If welding deformation causes local misalignment of the references, this will be reflected, mirroring the physical situation and thus improving the accuracy of the simulated welding.

[0068] Step S60: Decompose the total welding deformation along the X-axis, Y-axis and Z-axis respectively, and display the deformation along the three directions of X-axis, Y-axis and Z-axis in the form of cloud diagram and measurement points respectively.

[0069] In the above steps, the simulation reference point is adjusted so that its position is consistent with the fixture reference point to obtain the total welding deformation. The total welding deformation is then decomposed along the X-axis, Y-axis and Z-axis, and the sub-deformation along the X-axis, Y-axis and Z-axis is displayed in the form of cloud diagrams and measurement points, which helps engineers read and analyze the results.

[0070] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made under the concept of the present invention using the contents of the present invention specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A method for improving the accuracy of welding deformation simulation, characterized in that, It includes the following steps: Obtain the digital models of multiple parts to be welded that have been meshed according to preset requirements; Define the welding nodes between multiple part digital models by means of pin-hole fitting; Obtain the limiting parameters containing the clearance amount to limit multiple said part digital models, wherein the limiting parameters containing the clearance amount include the clearance amount value between the actually to-be-welded parts and the limiting components. During simulation, in the first step of the simulation, the contact calculation between the support and the part is carried out, and then in the second step, the actual clearance state is simulated, and the clearance amount between the support and the part is substituted into the simulation; Obtain the input simulation welding information and perform simulation welding according to the simulation welding information.

2. The method for improving the accuracy of welding deformation simulation as described in claim 1, characterized in that, In the step of obtaining the digital models of multiple parts to be welded that have been meshed according to preset requirements: The digital models of multiple parts to be welded are meshed using hexahedron meshes.

3. The method for improving the accuracy of welding deformation simulation as described in claim 2, characterized in that, Set the thickness of the hexahedron mesh to h, the length to L, and the width to w, where: 0 < h / L ≤ 1 / 5; and / or, 0.7 ≤ L / w ≤ 1.

5.

4. The method for improving the accuracy of welding deformation simulation as described in claim 1, characterized in that, Among the digital models of multiple parts to be welded, the interference amount between adjacent two part digital models is less than 0.02 mm.

5. The method for improving the accuracy of welding deformation simulation as described in claim 1, characterized in that, In the step of defining the welding nodes between multiple part digital models by means of pin-hole fitting: Set the clearance between the outer wall surface of the positioning pin and the inner wall surface of the positioning hole to I, where 0.03 mm ≤ I ≤ 0.05 mm.

6. The method for improving the accuracy of welding deformation simulation as described in claim 5, characterized in that, On the part digital model provided with the positioning hole, multiple meshes surrounding the periphery of the positioning hole are arranged to be gradually denser in the direction from the edge to the middle of the positioning hole.

7. The method for improving the accuracy of welding deformation simulation as described in claim 1, characterized in that, [[ID= 8. The method for improving the accuracy of welding deformation simulation as described in claim 7, characterized in that, ​ ​ ​ ​ 9. The method for improving the accuracy of welding deformation simulation as described in claim 1, characterized in that, ​ ​ ​

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