Method for evaluating forming effect of covered edge, method for designing covered edge and product

Abstract

The embodiment of the invention provides a method for evaluating a covered edge forming effect, a method for designing a covered edge and a product. The method comprises the steps that a target covered edge forming limit diagram corresponding to a to-be-evaluated object is determined; a failure attribute value of the to-be-evaluated object is obtained, and the failure attribute value is used for representing the strain state of the to-be-evaluated object in the edge covering forming process; determining a point corresponding to the failure attribute value on a two-dimensional coordinate system; and according to a target area where the point is located on the target edge-covering forming limit diagram, determining an edge-covering forming effect of the object to be evaluated. According to the embodiment of the invention, the covered edge forming evaluation result of the to-be-evaluated object is obtained according to the strain state, the covered edge failure risk of the to-be-evaluated object in the covered edge forming process can be effectively predicted, then the problem that the debugging period is prolonged due to covered edge failure and the like can be solved, and the covered edge design speed and the design level of the covered edge process can be improved.

Description

Technical Field

[0001] The present application relates to the field of industrial product design. Specifically, embodiments of the present application relate to a method for evaluating hemming forming effects, a method for designing hemming, and a product. Background Art

[0002] Hemming is a common process used in the manufacturing of various products, such as automobile bodies, furniture, clothing, etc. The main purpose of hemming is to protect the edges of the product from wear, scratches or cuts, while improving the aesthetics and durability of the product.

[0003] During the hemming process, the corresponding products may have product problems such as cracking and wrinkling. In order to avoid such problems, the relevant technology will adopt a non-dead design in areas such as corners or steps, and the non-dead design is easy to cause product damage or affect the product appearance. Therefore, in order to design beautiful or improve the service life of the product, the relevant technology provides a dead design for the corresponding product. However, the dead design is more likely to cause problems such as necking or cracking and wrinkling in the hemming process. In order to deal with such problems, the relevant new technology needs to conduct on-site verification of the fully wrapped products. If it is confirmed that the product with the dead design has cracking or necking failure, it is necessary to restore the product to the half-wrapped design. Obviously, this will cause mold rectification, longer debugging cycle, and increased design costs. Among them, aluminum plates have poor formability, and such problems are more serious. It should be noted that the dead design refers to the process of making the inner and outer panels fit tightly together during the hemming process to form a firm and inseparable connection state. This design usually requires no gap or very small gap between the inner and outer panels after hemming to achieve high strength and high sealing requirements. The non-deadlock design is relatively loose. It allows the inner and outer panels to maintain a certain gap or a separable connection state during the hemming process, and allows a certain degree of freedom between the inner and outer panels, which can reduce the hemming quality problems caused by factors such as material deformation and dimensional errors.

[0004] That is to say, in the field of hemming, relevant technologies can use full hemming instead of half hemming (or non-hemming) to improve service life and aesthetics. However, full hemming can easily cause the hemming object to have the risk of failure such as cracking and wrinkling. The relevant technology can only change from full hemming to half hemming mode when the full hemming has cracking and other failures. Therefore, this processing method significantly increases the debugging time in the hemming process development process, and the hemming efficiency is low. Summary of the invention

[0005] The purpose of the embodiments of the present application is to provide a method for evaluating the hemming forming effect, a method and product for designing hemming. The embodiments of the present application obtain the hemming forming evaluation result of the object to be evaluated according to the strain state, which can effectively predict the hemming failure risk (for example, necking or cracking) of the object to be evaluated during the hemming process, thereby solving the problem of increased debugging cycle caused by hemming failure, etc., and improving the aesthetics of the hemming design and the design level of the hemming process.

[0006] In a first aspect, an embodiment of the present application provides a method for evaluating the edge forming effect, the method comprising: determining a target edge forming limit diagram corresponding to an object to be evaluated; obtaining a failure attribute value of the object to be evaluated, wherein the failure attribute value is used to characterize the strain state of the object to be evaluated during the edge forming process; determining a point corresponding to the failure attribute value on a two-dimensional coordinate system; and determining the edge forming effect of the object to be evaluated according to a target area where the point is located on the target edge forming limit diagram.

[0007] The embodiments of the present application determine the forming effect of the object to be evaluated by determining the positional relationship between the point corresponding to the failure attribute value of the object to be evaluated and the target hemming forming limit diagram (the diagram is a plurality of regions with different forming effects determined by the failure attribute values ​​of the sample), so as to predict the failure risk of the object to be evaluated in the hemming forming, and then the hemming design parameters can be corrected in real time to improve the efficiency of the hemming forming.

[0008] In some embodiments, the failure attribute value includes an edge failure coefficient value and a failure coefficient increment value.

[0009] Some embodiments of the present application use hemming failure coefficient values ​​and failure coefficient increment values ​​to characterize the strain state during the hemming forming process, thereby improving the accuracy of hemming failure risk prediction.

[0010] In some embodiments, the target edge forming limit diagram includes multiple areas with different forming effects, and the multiple areas with different forming effects include: a failure area and a non-failure area, and the non-failure area includes: a risk area and a safety area, wherein the forming effect of the object to be evaluated is determined according to the target area where the point is located on the target edge forming limit diagram, including: if the point is located in the failure area, it is confirmed that the object to be evaluated has an edge failure; if the point is located in the risk area, it is confirmed that the object to be evaluated has an edge failure risk; if the point is located in the safety area, it is confirmed that the object to be evaluated does not have an edge failure risk.

[0011] Some embodiments of the present application can predict the forming effect of the object to be evaluated by determining the specific forming effect area where the coordinate values ​​corresponding to the object to be evaluated are located on the target hemming forming limit diagram, thereby improving the accuracy and objectivity of the forming effect prediction.

[0012] In some embodiments, determining a target hemming forming limit diagram corresponding to the object to be evaluated includes: obtaining plate attribute information of the object to be evaluated; and selecting a hemming forming limit diagram that matches the plate attribute information from a set of hemming forming limit diagrams as the target hemming forming limit diagram.

[0013] Some embodiments of the present application will pre-draw the edge forming limit diagrams corresponding to each type of samples in the multiple types of samples, and then select the target edge forming limit diagram corresponding to the object to be evaluated from these diagrams, thereby improving the data processing speed of edge failure risk assessment for the object to be evaluated.

[0014] In some embodiments, determining a target edge forming limit diagram corresponding to the object to be evaluated includes: collecting samples; obtaining sample failure attribute values ​​of at least some of the samples, wherein the sample failure attribute values ​​include: an edge failure coefficient value and a failure coefficient increment value; obtaining sample failure attribute values ​​of samples matching the object to be evaluated based on the sample failure attribute values, and obtaining the target edge forming limit diagram based on the sample failure attribute values ​​of the samples matching the object to be evaluated.

[0015] The hemming forming limit diagram of some embodiments of the present application is obtained by obtaining the failure attribute value of each sample, so the hemming forming limit diagram can more objectively and accurately reflect the hemming failure risk of the object to be evaluated.

[0016] In some embodiments, the failure coefficient increment value is determined by the hemming failure coefficient value and the flanging failure coefficient value, and the flanging failure coefficient value is determined by calculating the failure coefficient of the stamping process.

[0017] The embodiment of the present application obtains the flanging failure coefficient value by acquiring the stamping process failure coefficient, and determines the failure increment coefficient value by calculating the difference between the flanging failure coefficient value and the hemming failure coefficient value.

[0018] In some embodiments, obtaining sample failure attribute values ​​of at least some of the samples includes: determining samples with failure phenomena among the samples as target samples; obtaining sample failure attribute values ​​of the target samples, wherein the sample failure attribute values ​​include an edge failure coefficient value and a failure coefficient increment value of the target samples.

[0019] Some embodiments of the present application obtain the edge forming limit diagram by plotting the coordinate values ​​of samples with failure phenomena, which can reduce the amount of data processing when obtaining the edge forming limit diagram, thereby improving the speed of obtaining the edge forming limit diagram.

[0020] In some embodiments, obtaining the sample failure attribute value of the sample matching the object to be evaluated according to the sample failure attribute value and obtaining the target edge-wrapping forming limit diagram according to the sample failure attribute value of the sample matching the object to be evaluated includes: taking the sample failure attribute value of the sample matching the object to be evaluated as the target coordinate value; in the two-dimensional coordinate system, determining the failure critical line, the failure coefficient boundary line and the failure coefficient incremental boundary line according to the target coordinate value; dividing the plane corresponding to the two-dimensional coordinate system into the multiple regions with different forming effects at least based on the failure critical line, the failure coefficient boundary line and the failure coefficient incremental boundary line, and obtaining the target edge-wrapping forming limit diagram according to the multiple regions with different forming effects.

[0021] Some embodiments of the present application obtain multiple boundary lines through the coordinate values ​​of relevant samples, and then divide the plane into multiple areas with different forming effects according to these boundary lines, thereby improving the accuracy of the obtained edge forming limit diagram.

[0022] In some embodiments, the matched samples are samples with failure phenomena, wherein determining the failure critical line according to the target coordinate value includes: determining the failure critical line according to a point on the boundary of the area covered by the target coordinate value on the plane.

[0023] In some embodiments of the present application, the failure critical line can be obtained only by drawing points corresponding to samples with failure phenomena on a plane, thereby increasing the speed of obtaining the failure critical line and saving processing time.

[0024] In some embodiments, determining the critical failure line according to a point on a boundary of an area covered by the target coordinate value on the plane includes: obtaining the critical failure line by connecting at least two points on the boundary.

[0025] Some embodiments of the present application obtain a critical failure line through points on a boundary determined by coordinate values, thereby improving the accuracy and objectivity of the obtained critical failure line.

[0026] In some embodiments, the matched samples include a first type of matching samples with failure phenomena and a second type of matching samples without failure phenomena, wherein determining the failure critical line according to the target coordinate value includes: obtaining a failure sample area by determining the target coordinate value of the first type of matching samples on the plane; obtaining a non-failure sample area by determining the target coordinate value of the second type of matching samples on the plane; and determining the failure critical line at the junction of the failure sample area and the non-failure sample area.

[0027] Some embodiments of the present application simultaneously plot all coordinate values ​​corresponding to samples with failure phenomena and samples without failure phenomena on a plane corresponding to a two-dimensional coordinate system, and then determine the failure critical line at the intersection of these coordinate values, thereby improving the accuracy of the obtained failure critical line.

[0028] In some embodiments, determining the critical failure line at the boundary between the failed sample region and the non-failed sample region includes: obtaining the critical failure line by connecting at least two points at the boundary.

[0029] Some embodiments of the present application draw failure critical lines by using points located at the intersection, which can improve the ease of obtaining the failure critical lines and increase the data processing speed.

[0030] In some embodiments, a failure coefficient boundary line and a failure coefficient increment boundary line are determined according to the target coordinate value, including: determining a line passing through the failure coefficient boundary value and parallel to the first coordinate axis as the failure coefficient boundary line, wherein the failure coefficient boundary value is obtained by determining the maximum value of the edge failure coefficient value corresponding to the first type of matching samples, and the first type of matching samples are matching samples with failure phenomena; determining a line passing through the failure coefficient increment boundary value and parallel to the second coordinate axis as the failure coefficient increment boundary line, wherein the failure coefficient increment boundary value is obtained by determining the maximum value of the failure coefficient increment value corresponding to the first type of matching samples.

[0031] Some embodiments of the present application determine the edge failure coefficient boundary line and the failure coefficient increment boundary line by counting the maximum values ​​of the coordinate values ​​of all samples, thereby improving the accuracy and objectivity of the two obtained lines.

[0032] In some embodiments, the plane corresponding to the two-dimensional coordinate system is divided into the multiple regions with different forming effects based at least on the failure critical line, the failure coefficient boundary line and the failure coefficient incremental boundary line, and the target edge forming limit diagram is obtained according to the multiple regions with different forming effects, including: the two open areas into which the plane is divided by the failure critical line, the failure coefficient boundary line and the failure coefficient incremental boundary line are respectively used as the failure area and the non-failure area, and the target edge forming limit diagram is obtained according to the failure area and the non-failure area.

[0033] The hemming forming limit diagram of some embodiments of the present application is divided into failure areas and non-failure areas by failure critical lines, failure coefficient boundary lines (determined according to the hemming failure coefficient value) and failure coefficient increment boundary lines, thereby more accurately evaluating whether the object to be evaluated will fail according to the current design parameters, and thus better correcting these design parameters.

[0034] In some embodiments, the plane corresponding to the two-dimensional coordinate system is divided into the multiple regions with different forming effects at least based on the failure critical line, the failure coefficient boundary line and the failure coefficient incremental boundary line, and the target edge forming limit diagram is obtained according to the multiple regions with different forming effects, including: obtaining a risk critical line according to the failure critical line, wherein the risk critical line is used to divide an area with failure risk on the plane corresponding to the two-dimensional coordinate system; and obtaining the target forming limit diagram by dividing the plane into a failure zone, a risk zone and a safety zone based on the failure critical line, the risk critical line, the failure coefficient boundary line and the failure coefficient incremental boundary line.

[0035] Some embodiments of the present application also introduce risk critical lines to divide the plane into more forming effect areas, so that the target hemming forming limit diagram of the embodiments of the present application can more accurately evaluate whether there is failure in the hemming of the object to be evaluated according to the current design parameters, whether there is a risk of failure, and whether it is determined that there is no failure.

[0036] In some embodiments, the target forming limit diagram is obtained by dividing the plane into a failure zone, a risk zone and a safety zone based on the failure critical line, the risk critical line, the failure coefficient boundary line and the failure coefficient incremental boundary line, including: determining the open area defined by the failure coefficient boundary line, the failure critical line and the failure coefficient incremental boundary line as the failure zone; determining the closed area defined by the failure coefficient boundary line, the failure critical line, the risk critical line and the failure coefficient incremental boundary line as the risk zone; determining the open area defined by the failure coefficient boundary line, the risk critical line and the failure coefficient incremental boundary line as the safety zone; and obtaining the target forming limit diagram based on the failure zone, the risk zone and the safety zone.

[0037] In some embodiments, obtaining the risk critical line according to the failure critical line includes: offsetting the failure critical line according to an offset amount to obtain the risk critical line, wherein the offset amount is a ratio of a first distance to a second distance, the first distance is the distance from the intersection of the failure coefficient boundary line and the failure coefficient increment boundary line to the risk critical line, and the second distance is the distance from the intersection of the failure coefficient boundary line and the failure coefficient increment boundary line to the failure critical line.

[0038] Some embodiments of the present application obtain the risk critical line through the offset, and then different offsets can be set according to different needs, thereby improving the versatility of the technical solution.

[0039] In a second aspect, some embodiments of the present application provide a method for designing hemming, the method comprising: obtaining an hemming forming effect corresponding to an object to be evaluated obtained by using a method as described in any one of the embodiments included in the first aspect; adjusting a design parameter value of the object to be evaluated according to the hemming forming effect to obtain a target hemming forming parameter value of the object to be evaluated.

[0040] In a third aspect, some embodiments of the present application provide a computer program product, including computer program instructions, which, when read and executed by a processor, execute the method described in any one of the embodiments of the first aspect.

[0041] In a fourth aspect, some embodiments of the present application provide an electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the method described in any one of the embodiments included in the first aspect can be implemented.

[0042] In a fifth aspect, some embodiments of the present application provide a device for evaluating the edge forming effect, the device comprising: a target edge forming limit diagram acquisition module, configured to determine a target edge forming limit diagram corresponding to an object to be evaluated; a failure attribute value acquisition module, configured to obtain failure attribute values ​​of the object to be evaluated, wherein the failure attribute values ​​are used to characterize the strain state of the object to be evaluated during the edge forming process; a failure attribute value corresponding point determination module, determining a point corresponding to the failure attribute value in a two-dimensional coordinate system; and an edge forming evaluation module, determining the edge forming effect of the object to be evaluated according to a target area where the point is located on the target edge forming limit diagram.

[0043] In a sixth aspect, an embodiment of the present application provides a device for evaluating the hemming forming effect, comprising: a forming evaluation result acquisition module, configured to obtain the hemming forming effect corresponding to the object to be evaluated obtained by using the method described in any of the above embodiments. An adjustment module, configured to adjust the design parameter value of the object to be evaluated according to the hemming forming effect, and obtain the target hemming forming parameter value of the object to be evaluated. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0045] Figure 1A schematic diagram of parameters for calculating failure coefficients provided in an embodiment of the present application;

[0046] Figure 2 One of the processes of the method for evaluating the hemming forming effect provided in the embodiment of the present application;

[0047] Figure 3 The second process of the method for evaluating the hemming forming effect provided in the embodiment of the present application;

[0048] Figure 4 The third process of the method for evaluating the hemming forming effect provided in the embodiment of the present application;

[0049] Figure 5 One of the schematic diagrams of the hemming forming limit diagram provided in the embodiment of the present application;

[0050] Figure 6 The second schematic diagram of the hemming forming limit diagram provided in the embodiment of the present application;

[0051] Figure 7 One of the flow charts of the method for evaluating the hemming forming effect provided in the embodiment of the present application;

[0052] Figure 8 A block diagram of the composition of the device for evaluating the hemming forming effect provided in an embodiment of the present application;

[0053] Fig. 9 A block diagram of the composition of the device for evaluating the hemming forming effect provided in an embodiment of the present application;

[0054] Fig.10 A schematic diagram of the composition of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0055] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application.

[0056] It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. At the same time, in the description of this application, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0057] Abbreviations and explanations of this application:

[0058] Body edging: refers to the process of bending the flange surface of the body outer panel inward along the shape edge and wrapping the inner panel that overlaps and fits with it to form a joint, which has the effect of enhancing the strength of the body.

[0059] Failure coefficient: refers to the maximum principal strain a of the material during deformation compared to the principal strain b corresponding to the secondary strain with the same maximum principal strain, that is, failure coefficient = a / b, such as Figure 1 shown.

[0060] Failure coefficient increment: refers to the difference in failure coefficients before and after hemming, that is, failure coefficient increment = hemming failure coefficient - flanging failure coefficient.

[0061] It should be noted that the failure coefficient of flange refers to the failure coefficient of the material after flange forming before hemming is performed; while the failure coefficient of hemming refers to the failure coefficient of the material in the corresponding area after hemming is completed. In the body hemming forming process, the failure coefficient is an important indicator for evaluating whether the material will experience failure phenomena such as necking and cracking during the deformation process. It is defined as the ratio of the maximum principal strain (expressed as a) of the material during the deformation process to the corresponding secondary strain (expressed as b, that is, the strain perpendicular to the direction of the maximum principal strain) under the same maximum principal strain. This coefficient is used to measure the strain distribution and possible failure mode of the material under set deformation conditions. In the body hemming process, the deformation of the material usually includes complex strain states such as bending, stretching and compression. The size of the failure coefficient can reflect the stability and ability of the material to resist failure under these strain states. For example, if the failure coefficient is large, it means that the maximum principal strain is more significant than the secondary strain, which may cause the material to be more prone to failure phenomena in the direction of the maximum principal strain, such as cracks, fractures or necking. On the contrary, if the failure coefficient is small, it means that the strain distribution of the material during the deformation process is more uniform and the ability to resist failure may be stronger. That is, a larger failure coefficient may mean that the material is more likely to fail in the direction of maximum principal strain, while a smaller failure coefficient indicates that the material has a more uniform strain distribution during deformation and a stronger ability to resist failure. Some embodiments of the present application may be applied to sheet metal hemming, for example, in the field of automobile body hemming.

[0062] The inventor of the present application has found through research that the fundamental reason for the problem of too long hemming debugging cycle in the related technology is that it is impossible to predict whether the hemming forming process will cause failure risks such as cracking, wrinkling, and necking (or necking) during the product full-hemming design stage. To solve this problem, the embodiment of the present application predicts the hemming failure risk of the object to be evaluated (for example, the object to be evaluated is the inner plate and outer plate that need to be hemmed) by collecting the failure attribute value of the sample to obtain the hemming forming limit diagram (for example, based on the computer-aided engineering CAE analysis tool, the corresponding failure attribute value is obtained according to the three-dimensional model data of the sample to obtain the coordinate value, and the hemming forming limit diagram is obtained according to the coordinate value). The embodiment of the present application can effectively predict the failure risks of hemming cracking, wrinkling or necking that may exist in the full-hemming process, improve the level of hemming forming design (for example, body hemming design) and shorten the process development cycle.

[0063] Please see Figure 2 , Figure 2 A method for evaluating the hemming forming effect provided in an embodiment of the present application includes:

[0064] S110, determining a target hemming forming limit diagram corresponding to the object to be evaluated.

[0065] For example, in some embodiments of the present application, the objects to be evaluated include inner panels and outer panels waiting for hemming treatment.

[0066] It should be noted that, in the embodiments of the present application, different edge forming limit diagrams correspond to different sheet material attribute information of the inner plate or outer plate, for example, the sheet material attribute information of the inner plate or outer plate includes material and thickness. In some embodiments of the present application, the target edge forming limit diagram includes multiple areas with different forming effects, and the multiple areas with different forming effects include: failure areas and non-failure areas. In other embodiments of the present application, the target edge forming limit diagram includes multiple areas with different forming effects, and the multiple areas with different forming effects include: failure areas, risk areas and safety areas. The object to be evaluated (or sample) corresponding to the point in the failure area will experience failure phenomena such as necking during the edge wrapping process, the object to be evaluated corresponding to the point in the non-failure area will not experience failure phenomena such as necking during the edge wrapping process, the object to be evaluated corresponding to the point in the risk area is more likely to experience failure phenomena such as necking during the edge wrapping process, and the object to be evaluated corresponding to the point in the safety area will not experience failure phenomena such as necking during the edge wrapping process.

[0067] S120, obtaining a failure attribute value of the object to be evaluated, wherein the failure attribute value is used to characterize a strain state of the object to be evaluated during a hemming forming process.

[0068] For example, in some embodiments of the present application, a computer-aided engineering (CAE) analysis tool can be used to simulate the hemming deformation process of the object to be evaluated and obtain the corresponding failure attribute value. The failure attribute value of the embodiment of the present application can predict the possible failure risk of the corresponding object to be evaluated during the actual hemming deformation process.

[0069] S130: Determine a point corresponding to the failure attribute value on a two-dimensional coordinate system.

[0070] For example, in some embodiments of the present application, a two-dimensional rectangular coordinate system is constructed based on two variables for quantifying failure attribute values ​​(i.e., the two variables are used as two coordinate axes of the two-dimensional rectangular coordinate system), and then the failure attribute value of the object to be evaluated is used as the coordinate value to determine the point on the plane defined by the two-dimensional coordinate system.

[0071] S140, determining the hemming forming effect of the object to be evaluated according to the target area where the point is located on the target hemming forming limit diagram.

[0072] For example, in some embodiments of the present application, the target edge forming limit diagram includes a failure zone and a non-failure zone, and the target area belongs to one of the two zones. In other embodiments of the present application, the target edge forming limit diagram includes a failure zone, a risk zone, and a safety zone, and the target area belongs to one of the three zones.

[0073] The embodiments of the present application determine the forming effect of the object to be evaluated by determining the positional relationship between the point corresponding to the failure attribute value of the object to be evaluated and the target hemming forming limit diagram (the diagram is a plurality of regions with different forming effects determined by the failure attribute values ​​of the sample), so as to predict the failure risk of the object to be evaluated in the hemming forming, and then the hemming design parameters can be corrected in real time to improve the efficiency of the hemming forming.

[0074] The following is an exemplary description of the process of obtaining the target hemming forming limit diagram recorded in S110.

[0075] In some embodiments of the present application, two parameters, namely, the edge failure coefficient and the failure coefficient increment, are used to quantify the failure attribute value. It is understandable that those skilled in the art may select other parameters to quantify the failure attribute value.

[0076] In some embodiments of the present application, samples with the same material and thickness as the inner plate and outer plate of the object to be evaluated are collected, and the target hemming forming limit diagram corresponding to the object to be evaluated is obtained based on these samples. It can be understood that in these embodiments, it is not necessary to obtain the hemming forming limit diagrams corresponding to each type of sample (different types of samples are distinguished by the material or thickness of the inner plate or outer plate) in advance.

[0077] In some other embodiments of the present application, it is necessary to pre-draw the edge forming limit diagrams corresponding to each type of sample to obtain multiple edge forming limit diagrams (or called edge forming limit diagram sets), wherein the materials or thicknesses of the inner plates or outer plates of different types of samples are different, and then select the edge forming limit diagram that matches the object to be evaluated from the multiple pre-drawn edge forming limit diagrams as the target edge forming limit diagram. For example, in some embodiments of the present application, the process of obtaining the target edge forming limit diagram corresponding to the object to be evaluated described in S110 exemplarily includes: the first step is to obtain the plate attribute information of the object to be evaluated. For example, in some embodiments of the present application, the plate attribute information includes the inner plate material, the inner plate thickness, the outer plate material and the outer plate thickness. The second step is to select the edge forming limit diagram corresponding to the sample consistent with the plate attribute information from the edge forming limit diagram set as the target edge forming limit diagram.

[0078] It should be noted that the set of hemming forming limit diagrams is pre-drawn hemming forming limit diagrams corresponding to each type of samples in the multiple types of samples. It can be understood that some embodiments of the present application select the hemming forming limit diagram that matches the plate attribute information of the object to be evaluated, that is, select the hemming forming limit diagram corresponding to the sample that is consistent with the plate attribute information of the object to be evaluated from multiple hemming forming limit diagrams. In other words, some embodiments of the present application will pre-draw the hemming forming limit diagrams of multiple types of samples, and then select the target hemming forming limit diagram corresponding to the object to be evaluated from these diagrams, so as to improve the data processing speed of the evaluation process of evaluating the hemming failure risk of the object to be evaluated.

[0079] For example, Figure 3 As shown, the process of obtaining a set of edge forming limit diagrams provided in some embodiments of the present application exemplarily includes:

[0080] S210, collect samples.

[0081] For example, in some embodiments of the present application, S210 exemplarily includes: collecting 3D digital models and on-site physical data of different vehicle models, different sheet material types and thicknesses, and different vehicle body parts, and these data include but are not limited to the following information:

[0082] Vehicle types: sedan, SUV, MPV, Wagon, etc.

[0083] Plate material: steel plate for automobile, aluminum plate, etc., thickness range: 0.45-1.3mm.

[0084] Body parts: front cover, rear cover, front and rear doors, roof and other parts that need hemming.

[0085] S220, obtaining sample failure attribute values ​​of at least some of the samples, wherein the sample failure attribute values ​​include: an edge failure coefficient value and a failure coefficient increment value.

[0086] It should be noted that, in some embodiments of the present application, for each type of samples, it is necessary to obtain the failure attribute value of each sample in this type of samples as the sample failure attribute value; in other embodiments of the present application, for each type of samples, it is necessary to obtain the failure attribute values ​​of some samples among these samples (for example, samples with failure phenomena such as necking or cracking) to obtain the sample failure attribute value.

[0087] For example, in some embodiments of the present application, S220 exemplarily includes: determining a sample with failure phenomenon in the sample as a target sample; obtaining a sample failure attribute value of the target sample, wherein the sample failure attribute value includes a hemming failure coefficient value and a failure coefficient increment value of the target sample. It should be noted that failure phenomena include: necking or cracking, etc. It can be understood that in some embodiments of the present application, the target sample is a sample with necking phenomenon, in other embodiments of the present application, the target sample is a sample with cracking phenomenon, and in still other embodiments of the present application, the target sample includes both samples with necking phenomenon and samples with cracking phenomenon.

[0088] It can be understood that some embodiments of the present application obtain the edge forming limit diagram by plotting the coordinate values ​​of samples with failure phenomena, which can reduce the amount of data processing when obtaining the edge forming limit diagram, thereby improving the speed of obtaining the edge forming limit diagram.

[0089] S230, obtaining each edge forming limit diagram in the edge forming limit diagram set according to the sample failure attribute value, it can be understood that the target edge forming limit diagram belongs to the diagram in the edge forming limit diagram set, in some embodiments of the present application, the corresponding edge forming limit diagrams are drawn for each type of sample to obtain the edge forming limit diagram set, wherein at least one of the inner plate material, inner plate thickness, outer plate material and outer plate thickness of different samples is different. For example, in some embodiments of the present application, S230 exemplarily includes: obtaining the sample failure attribute value of the sample matching the object to be evaluated according to the sample failure attribute value, and obtaining the target edge forming limit diagram according to the sample failure attribute value of the sample matching the object to be evaluated.

[0090] Since the hemming forming limit diagram of some embodiments of the present application is obtained by obtaining the failure attribute value of each sample, the hemming forming limit diagram can more objectively and accurately reflect the hemming failure risk of the object to be evaluated.

[0091] It can be understood that the process of drawing the forming limit diagrams of the hemming is the same as that of drawing the forming limit diagrams of the hemming set, so the process of drawing the forming limit diagram of the hemming is exemplarily described below by taking the process of drawing the target forming limit diagram of the hemming as an example.

[0092] The implementation of S230 is described below by way of example.

[0093] In some embodiments of the present application, Figure 4 As shown, S230 exemplarily includes:

[0094] S231: Using the sample failure attribute value of the sample matching the object to be evaluated as the target coordinate value.

[0095] It should be noted that the sample matching the object to be evaluated is a sample having the same material and thickness as the inner and outer plates of the object to be evaluated.

[0096] In some embodiments of the present application, samples with the same inner plate material, inner plate thickness, outer plate material and outer plate thickness as those of the object to be evaluated are used as samples for drawing the target forming limit diagram (i.e., samples that match the object to be evaluated), and the sample failure attribute values ​​of these samples are obtained as target coordinate values.

[0097] S232, in the two-dimensional coordinate system, determining a failure critical line, a failure coefficient boundary line, and a failure coefficient increment boundary line according to the target coordinate value.

[0098] It should be noted that, in some embodiments of the present application, the failure critical line, the failure coefficient boundary line and the failure coefficient increment boundary line are at least used to confine the points corresponding to the coordinate values ​​of the samples with failure phenomena (including the edge failure coefficient values ​​and the failure coefficient increment values) to one area, and to confine the points corresponding to the coordinate values ​​of the samples without failure phenomena to another different area.

[0099] The process of drawing the failure critical line is described below as an example.

[0100] For example, in some embodiments of the present application, the matched sample is a sample with a failure phenomenon (in other embodiments of the present application, such samples are referred to as first-class matching samples), and the process of determining the failure critical line according to the target coordinate value recorded in S232 exemplarily includes: determining the failure critical line according to the point on the boundary of the area covered by the target coordinate value on the plane. For example, in some embodiments of the present application, a straight line or a curve can be determined on one side of the point on the boundary as the failure critical line. For example, in other embodiments of the present application, the process of determining the failure critical line according to the point on the boundary of the area covered by the target coordinate value on the plane exemplarily includes: obtaining the failure critical line by connecting at least two points on the boundary. In some embodiments of the present application, the failure critical line is a straight line obtained by connecting two points on the boundary, and in other embodiments of the present application, the failure critical line is a curve obtained by connecting multiple points on the boundary. It is not difficult to understand that some embodiments of the present application only need to obtain the failure critical line by drawing points corresponding to the failure attribute values ​​of the samples with failure phenomena on the plane, thereby improving the speed of obtaining the failure critical line and saving processing time. For example, some embodiments of the present application obtain a failure critical line through points on the boundary determined by the target coordinate value, thereby improving the accuracy and objectivity of the obtained failure critical line. It should be noted that in some embodiments of the present application, samples with failure phenomena on the plane defined by the two-dimensional coordinate system are located on one side of the failure critical line, that is, the failure critical line can divide the points corresponding to the failed sample coordinate values ​​and the points corresponding to the non-failed sample coordinate values ​​into two different areas on the coordinate plane. For example, in the following example, the points (NG) corresponding to all the necking (as an example of failure phenomenon) hemming samples are on the right side of this failure critical line.

[0101] For example, in some embodiments of the present application, the matching samples include a first type of matching samples with failure phenomena (for example, Figure 5 or Figure 6 NG samples) and the second type of matching samples without failure phenomenon (for example, Figure 5 or Figure 6 The process of determining the failure critical line according to the target coordinate value in S232 exemplarily includes: determining the target coordinate value of the first type of matching sample on the plane to obtain the failure sample area (for example, Figure 5 The area occupied by the coordinate values ​​of the NG samples, or Figure 6 The area occupied by the coordinate values ​​of the NG samples); by determining the target coordinate values ​​of the second type of matching samples on the plane, a non-failed sample area (for example, Figure 5 The area occupied by the coordinate values ​​of the OK samples, or Figure 6The area occupied by the coordinate values ​​of the OK samples); the failure critical line is determined at the junction of the failed sample area and the non-failed sample area. For example, in some embodiments of the present application, the process of determining the failure critical line at the junction of the failed sample area and the non-failed sample area exemplarily includes: obtaining the failure critical line by connecting at least two points at the junction, or determining a curve or a straight line at the middle position of the junction as the failure critical line. It should be noted that in some embodiments of the present application, a straight line or a curve can be drawn at the center of the junction as the failure critical line; in some embodiments of the present application, the failure critical line can be determined by the point corresponding to the target coordinate value of the first type of matching sample at the junction (for example, connecting such two or more points), or the failure critical line can be determined by the point corresponding to the target coordinate value of the second type of matching sample at the junction (for example, connecting such two or more points). It can be understood that some embodiments of the present application can further improve the accuracy of the obtained failure critical line by simultaneously drawing all coordinate values ​​corresponding to the samples with failure phenomenon and the samples without failure phenomenon on the plane corresponding to the two-dimensional coordinate system.

[0102] It should be noted that the first type of matching samples and the second type of matching samples in some embodiments of the present application are samples with the same plate attribute information as the object to be evaluated (i.e., the thickness of the inner and outer plates and the material of the plates are the same) (i.e., samples that match the object to be evaluated), and the difference between the first type of matching samples and the second type of matching samples is that the first type of matching samples are matching samples with failure phenomena such as necking or cracking, and the second type of matching samples are matching samples without failure phenomena. It can be understood that some embodiments of the present application can improve the simplicity of obtaining the failure critical line and improve the data processing speed by drawing the failure critical line through the points located at the junction.

[0103] The following is an example of the process of drawing the failure coefficient boundary line and the failure coefficient increment boundary line.

[0104] In some embodiments of the present application, the process of determining the failure coefficient boundary line and the failure coefficient increment boundary line according to the coordinate value exemplarily includes: determining a line passing through the failure coefficient boundary value and parallel to the first coordinate axis as the failure coefficient boundary line, wherein the failure coefficient boundary value is obtained by determining the maximum value of the hemming failure coefficient value corresponding to the first type of matching sample (i.e., the sample that is consistent with the plate attribute information of the object to be evaluated and has a failure phenomenon); determining a line passing through the failure coefficient increment boundary value and parallel to the second coordinate axis as the failure coefficient increment boundary line, wherein the failure coefficient increment boundary value is obtained by determining the maximum value of the failure coefficient increment value corresponding to the first type of matching sample. It should be noted that, in some embodiments of the present application, the first coordinate axis is the failure coefficient increment axis and the second coordinate axis is the failure coefficient axis (the axis is the axis corresponding to the hemming failure coefficient value); in other embodiments of the present application, the first coordinate axis is the failure coefficient axis (the axis is the axis corresponding to the hemming failure coefficient value), and the corresponding second coordinate axis is the failure coefficient increment axis.

[0105] It should be noted that in some embodiments of the present application, the failure coefficient boundary value is equal to or greater than the minimum value of the hemming failure coefficient value corresponding to the first type of matching samples (based on samples with consistent property information of the inner and outer plates of the object to be evaluated and with failure phenomena such as necking); the failure coefficient increment boundary value is equal to or greater than the minimum value of the failure coefficient increment value corresponding to the first type of matching samples. Some embodiments of the present application determine the hemming failure coefficient boundary line and the failure coefficient increment boundary line by counting the maximum values ​​of the coordinate values ​​of all samples, thereby improving the accuracy and objectivity of the two obtained lines.

[0106] S233, dividing the plane corresponding to the two-dimensional coordinate system into the multiple regions with different forming effects based at least on the failure critical line, the failure coefficient boundary line, and the failure coefficient increment boundary line, and obtaining the target hemming forming limit diagram according to the multiple regions with different forming effects. It is not difficult to understand that some embodiments of the present application obtain multiple boundary lines through the coordinate values ​​of relevant samples, and then divide the plane into multiple regions with different forming effects according to these boundary lines, so as to improve the accuracy of the obtained hemming forming limit diagram.

[0107] The implementation process of S233 is described below by way of example.

[0108] In some embodiments of the present application, S233 exemplarily includes: dividing the plane into two open areas by the failure critical line, the failure coefficient boundary line, and the failure coefficient increment boundary line as the failure area and the non-failure area, respectively, and obtaining a target edge forming limit diagram according to the failure area and the non-failure area. For example, an image corresponding to the failure area and the non-failure area on a two-dimensional plane is determined as a target edge forming limit diagram.

[0109] Combine the following Figure 5 The failure area and the non-failure area are shown exemplarily.

[0110] like Figure 5 As shown in the figure, the failure critical line L3, the failure coefficient boundary line L1 and the failure coefficient increment boundary line L2 divide the plane into two open areas, one of which is a failure area and the other is a non-failure area. Figure 5 The area where all NG points are located belongs to the failure area, and the area where all OK points are located is the non-failure area. It can be understood that if it is determined that the point corresponding to the coordinate value of the object to be evaluated is located in the failure area, it can be predicted that the object to be evaluated will fail during the hemming process; if it is determined that the point corresponding to the coordinate value of the object to be evaluated is located in the non-failure area, it can be predicted that the object to be evaluated will not fail during the hemming process.

[0111] It is not difficult to understand that the hemming forming limit diagram of some embodiments of the present application is divided into failure areas and non-failure areas by failure critical lines, failure coefficient boundary lines and failure coefficient increment boundary lines, so that it is possible to more accurately evaluate whether the object to be evaluated will fail according to the current design parameters, and thus better correct these design parameters.

[0112] In some embodiments of the present application, S233 exemplarily includes:

[0113] In the first step, a risk critical line is obtained according to the failure critical line, wherein the risk critical line is used to divide an area with failure risk (ie, risk area) on the plane corresponding to the two-dimensional coordinate system.

[0114] In some embodiments of the present application, the risk critical line is obtained by translating the failure critical line. In other embodiments of the present application, the risk critical line is obtained by offsetting the failure critical line.

[0115] For example, in some embodiments of the present application, the first step exemplarily includes: performing offset processing on the failure critical line according to the offset amount to obtain the risk critical line, wherein the offset amount is the ratio of the first distance to the second distance, the first distance is the distance from the intersection of the failure coefficient boundary line and the failure coefficient increment boundary line to the risk critical line, and the second distance is the distance from the intersection of the failure coefficient boundary line and the failure coefficient increment boundary line to the failure critical line. Figure 6As shown, point P1 is the intersection of the failure coefficient boundary line and the failure coefficient increment boundary line, P1P0 represents the distance from point P1 to the risk critical line L4, and P1P2 represents the distance from point P1 to the failure critical line L3. It can be understood that some embodiments of the present application obtain the risk critical line through the offset, and then different offsets can be set according to different requirements to improve the versatility of the technical solution.

[0116] In the second step, the plane is divided into a failure zone, a risk zone and a safety zone based on the failure critical line, the risk critical line, the failure coefficient boundary line and the failure coefficient increment boundary line, and the target forming limit diagram is obtained according to the failure zone, the risk zone and the safety zone. For example, the whole image composed of the failure zone, the risk zone and the safety zone is used as the target forming limit diagram.

[0117] like Figure 6 As shown, the open area located in the upper right corner of the plane defined by the failure coefficient boundary line L1, the failure critical line L3 and the failure coefficient increment boundary line L2 belongs to the failure zone. For example, Figure 6 All NG points are located in the failure zone; the closed area defined by the failure coefficient boundary line L1, the failure critical line L3, the risk critical line L4 and the failure coefficient increment boundary line L2 belongs to the risk zone; the open area defined by the failure coefficient boundary line L1, the risk critical line L4 and the failure coefficient increment boundary line L2 belongs to the safe zone.

[0118] It is not difficult to understand that some embodiments of the present application also introduce risk critical lines to divide the plane into more forming effect areas, so that the target hemming forming limit diagram of the embodiments of the present application can more accurately evaluate whether there is failure in the hemming of the object to be evaluated according to the current design parameters, whether there is a risk of failure, and whether it is determined that there is no failure.

[0119] The following is an exemplary description of the process of predicting the hemming failure risk of the object to be evaluated based on the obtained target hemming forming limit diagram.

[0120] In order to determine the failure risk of the object to be evaluated, in some embodiments of the present application, the failure attribute value of the object to be evaluated is characterized by the hemming failure coefficient value and the failure coefficient increment value. It is not difficult to understand that some embodiments of the present application use the hemming failure coefficient value and the failure coefficient increment value to characterize the strain state during the hemming forming process, thereby improving the accuracy of the prediction of the hemming failure risk.

[0121] In some embodiments of the present application, the target hemming forming limit diagram includes multiple areas with different forming effects, and the multiple areas with different forming effects include: a failure area and a non-failure area, and the non-failure area includes: a risk area and a safety area. The corresponding S140 exemplarily includes: if the point is located in the failure area, it is confirmed that the object to be evaluated has an hemming failure; if the point is located in the risk area, it is confirmed that the object to be evaluated has an hemming failure risk; if the point is located in the safety area, it is confirmed that the object to be evaluated does not have an hemming failure risk.

[0122] Combination Figure 6 To illustrate, if it is confirmed that the point corresponding to the object to be evaluated (the two coordinate values ​​of the point in the two-dimensional coordinate system respectively include the edge failure coefficient value and the failure coefficient increment value corresponding to the object to be evaluated) is located in the failure area defined by the failure coefficient boundary line L1, the failure critical line L3 and the failure coefficient increment boundary line L2, then it is predicted that the object to be evaluated will fail during the actual edge wrapping process; if it is confirmed that the point corresponding to the object to be evaluated is located in the risk area defined by the failure coefficient boundary line L1, the failure critical line L3, the risk critical line L4 and the failure coefficient increment boundary line L2, then it is predicted that the object to be evaluated may fail during the actual edge wrapping process; if it is confirmed that the point corresponding to the object to be evaluated is located in the safety area defined by the failure coefficient boundary line L1, the risk critical line L4 and the failure coefficient increment boundary line L2, then it is predicted that the object to be evaluated will not fail during the actual edge wrapping process.

[0123] Some embodiments of the present application can predict the forming effect of the object to be evaluated by determining the specific forming effect area where the coordinate values ​​corresponding to the object to be evaluated are located on the target hemming forming limit diagram, thereby improving the accuracy and objectivity of the forming effect prediction.

[0124] The following is a specific example of a process of drawing a target hemming forming limit diagram and determining the hemming forming effect of an object to be evaluated provided by some embodiments of the present application. The process exemplarily includes:

[0125] S1: Collect samples.

[0126] S2: Stamping process simulation analysis to obtain the flange failure coefficient value.

[0127] S3: Simulate and analyze the hemming process to obtain the hemming failure coefficient value, and then obtain the failure coefficient increment value.

[0128] S4: Draw the forming limit diagram of the hemming, that is, take the hemming failure coefficient value and the failure coefficient increment value as the coordinate value of the point on the plane of the two-dimensional coordinate system, and draw the relevant coordinate values ​​to obtain the forming limit diagram of the hemming.

[0129] S5: Determine the hemming formability result, that is, analyze the failure risk of the hemming forming of the object to be evaluated according to the obtained hemming forming limit diagram.

[0130] The above five steps are exemplarily described below.

[0131] S1: The sample collection process includes: collecting 3D digital models and on-site physical data of different car models, different sheet material types and thicknesses, and different car body parts. These data include but are not limited to the following information:

[0132] Vehicle types: sedan, SUV, MPV, Wagon, etc.

[0133] Plate material: steel plate for automobile, aluminum plate, etc., thickness range: 0.45-1.3mm.

[0134] Body parts: front cover, rear cover, front and rear doors, roof and other parts that need hemming.

[0135] S2: Calculate the failure coefficient of the stamping process to obtain the flanging failure coefficient value.

[0136] In some embodiments of the present application, the steps exemplarily include:

[0137] The first step is to formulate a stamping process plan based on the characteristics of the outer panel. The plan includes: number of processes, process content, and process simulation analysis. The analysis results include: cracking, max failure, wrinkling, surface defects, etc. The process of process arrangement includes: stretching, trimming, etc.

[0138] The second step is to output the simulation results, i.e. the grid analysis file; calculate the failure coefficient of the risk position and obtain the flange failure coefficient value of the sample. It can be understood that the same technical means can be used to obtain the flange failure coefficient value of the object to be evaluated.

[0139] That is to say, in some embodiments of the present application, the process of obtaining the flanging failure coefficient of the sample includes: simulating the stamping operation of the outer plate of each sample according to the specified stamping process to obtain the simulated stamping processing results corresponding to the outer plate of each sample; determining the risk position of the outer plate of the corresponding sample according to the simulated stamping processing results, and determining the flanging failure coefficient value of each risk position (corresponding to the failure coefficient value of the sample with failure phenomenon obtained). For example, in some embodiments of the present application, determining the risk position of the outer plate of the corresponding sample according to the simulated stamping processing results, and determining the flanging failure coefficient value of each risk position exemplarily includes: finding the maximum principal strain a corresponding to each risk position formed in the flanging process from the simulated stamping processing results; finding the principal strain value b corresponding to the secondary strain at each risk position; and calculating the flanging failure coefficient value of the sample at each risk position in the flanging process according to the failure coefficient calculation formula.

[0140] It should be noted that in the flanging process, the deformation behavior of the material is complex and multidimensional, usually involving strains in multiple directions. In order to evaluate the failure risk during the flanging process, some embodiments of the present application consider using the strain ratio (i.e., failure coefficient) as an indicator. The failure coefficient mentioned here is defined as the ratio of the maximum principal strain a of the material during the deformation process to the principal strain b corresponding to the secondary strain under the same maximum principal strain condition, that is, failure coefficient = a / b.

[0141] The following is the process of calculating the flange failure coefficient value in combination with this formula:

[0142] 1. Clarify the direction of response

[0143] 1. Principal strain: During material deformation, there are usually three principal strain directions, corresponding to the three orthogonal axes of the material. The maximum principal strain a is the one with the largest strain value among these three directions.

[0144] 2. Secondary strain: Secondary strain is the strain in the other two directions besides the maximum principal strain direction. Here, it is necessary to determine the principal strain b corresponding to the secondary strain under the same conditions as the maximum principal strain (i.e., under the same deformation state).

[0145] 2. Collecting Strain Data

[0146] 1. Experimental measurement: Measure the strain distribution on the material surface during the flanging process through experimental methods (such as strain gauge measurement, digital image correlation technology, etc.).

[0147] 2. Simulation analysis: Use simulation tools such as finite element analysis (FEA) to simulate the flanging process and extract the data of maximum principal strain and secondary strain.

[0148] 3. Calculate the failure coefficient

[0149] 1. Determine the maximum principal strain: From the results of experimental measurement or simulation analysis, find the maximum principal strain value a during the flanging process.

[0150] 2. Determine the principal strain corresponding to the secondary strain: Under the same deformation state, find the corresponding principal strain value b in the secondary strain. This usually requires detailed analysis in the simulation results or experimental measurement.

[0151] 3. Calculate the failure coefficient: According to the formula failure coefficient = a / b, calculate the failure coefficient during the flanging process.

[0152] It is understandable that the embodiments of the present application can evaluate the failure risk by obtaining the failure coefficient value, and the failure coefficient reflects the deformation unevenness of the material during the flanging process. When the failure coefficient is large, it means that the deformation of the material in a certain direction is much greater than that in other directions, which may lead to failure phenomena such as cracking and wrinkling. The embodiments of the present application can also guide process optimization through the value of the flanging failure coefficient: by calculating the failure coefficient, the potential failure risk points in the flanging process can be identified, and then the adjustment and optimization of the process parameters can be guided to reduce the risk of failure. It should be noted that the calculation method and application range of the failure coefficient may vary depending on the material type, process conditions and failure mode. Therefore, in practical applications, it is necessary to comprehensively consider and analyze the specific circumstances.

[0153] S3: Calculate the failure coefficient increment of the hemming process. In some embodiments of the present application, the process needs to complete the hemming simulation of the sample to obtain the hemming failure coefficient value, and then calculate the difference between the hemming failure coefficient value and the flanging failure coefficient value to obtain the failure coefficient increment value. It can be understood that the same technical means can be used to obtain the hemming failure coefficient value and the failure coefficient increment value of the object to be evaluated.

[0154] The process exemplarily includes:

[0155] (1) Data import

[0156] The outer panel data (for example, 3D model data such as outer panel geometry data and material data) is imported into the S2 step result, that is, the stamping process analysis ASM file.

[0157] Inner panel data (e.g., 3D model data such as inner panel geometry data and material data), which can include process analysis ASM files or theoretical digital models (excluding stamping process analysis results)

[0158] (2) Panel positioning

[0159] The inner plate is positioned by positioning pins, and the stamping direction of the hemming die is parallel to the normal direction of the inner plate reference hole. In special cases, considering the balance of the parts and the hemming angle, the stamping direction is allowed to have a maximum angle of 3 degrees with the direction of the inner plate reference hole. When the outer plate contains holes in the inner plate area, positioning pins and edge contours are used for positioning; if the hemmed outer plate product has no holes, a positioning plate is added to the outer contour of the flange for positioning.

[0160] Panel positioning is a key step before hemming, which ensures the precise alignment of the inner and outer panels during the hemming process, thereby ensuring the quality and precision of the final product. The specific steps and methods of panel positioning may vary depending on the specific product and application scenario, but generally include the following aspects: Positioning with locating pins: Use locating pins to fix the inner panel to the mold or fixture to ensure that the position of the inner panel is accurate. The locating pins usually cooperate with the reference holes on the inner panel to achieve fast and accurate positioning. Contour positioning: For outer panels, especially when the outer panel product has no holes, a contour positioning plate can be used for positioning. This method achieves precise positioning of the outer panel by matching the outer contour of the outer panel's flange with the contour on the positioning plate. Multi-point positioning: In some cases, it may be necessary to use multiple positioning points to simultaneously fix the inner and outer panels to ensure their stability and consistency during the hemming process.

[0161] The following process is achieved through the above two steps of data import and panel positioning: Geometric modeling: First, according to the 3D data and process requirements of the product, the geometric model of the inner and outer panels and the mold is established; Material property setting: Assign corresponding material properties to the geometric model, including elastic modulus, yield strength, tensile strength, hardening index, etc.; Boundary condition setting: Simulate boundary conditions such as stamping speed, temperature, lubrication conditions, etc. in actual production.

[0162] (3) Simulation calculation: simulate the hemming process through CAE finite element analysis.

[0163] With the development of computer technology, CAE (Computer Aided Engineering) finite element analysis is increasingly used in hemming. Through CAE finite element analysis, the hemming process can be simulated before actual production. The embodiment of the present application predicts possible problems in hemming through the system. The specific simulation analysis process is: run the finite element analysis software, simulate the hemming process, observe the stress, strain distribution and deformation of the material, and obtain the hemming simulation results of the hemmed sample. Complete the hemming process.

[0164] That is to say, the failure coefficient increment value of some embodiments of the present application is determined by the hemming failure coefficient value and the flanging failure coefficient value, and the flanging failure coefficient value is determined by calculating the failure coefficient of the stamping process.

[0165] Output the hemming failure coefficient value and obtain the failure coefficient increment value. That is, calculate the hemming failure coefficient value according to the strain result obtained by simulation and the calculation formula of the hemming failure coefficient, and then obtain the failure coefficient increment value according to the above formula.

[0166] S4: The process of drawing the simulated failure limit diagram, i.e., drawing the forming limit diagrams of each hemming edge includes:

[0167] (1) Establishing a coordinate system

[0168] The two-dimensional rectangular coordinate system is defined with the hemming failure coefficient value (corresponding to the failure coefficient axis) and the failure coefficient increment value (corresponding to the failure coefficient increment axis) as the two coordinate axes. Figure 5 or Figure 6 As shown, the established two-dimensional coordinate axis system includes: failure coefficient axis (X axis positive direction), failure coefficient increment axis (Y axis positive direction). It should be noted that Figure 5 and Figure 6 The failure coefficient is the edge failure coefficient value. Because the edge failure coefficient and the failure coefficient increment have no negative values, the coordinates only take the positive direction of the XY axis. It can be understood that in other embodiments of the present application, the vertical axis can also be used as the failure coefficient axis and the horizontal axis can be used as the failure coefficient increment axis. The embodiments of the present application do not limit the specific type of the defined two-dimensional coordinate system.

[0169] (2) Drawing the cracking critical line (i.e., drawing L1, L2, L3). Drawing the cracking critical line exemplarily includes: drawing the failure critical line, the failure coefficient boundary line (i.e., the line determined by the edge failure coefficient value of the sample) and the failure coefficient increment boundary line.

[0170] From each hemming (or each sample) corresponding to the data, the hemming position points that belong to the same material and the same thickness and have the necking phenomenon are selected to obtain the target sample, that is, the set of critical cracking points is obtained; the hemming failure coefficient value of the corresponding point and the incremental value of the failure coefficient before and after the hemming are confirmed, and then the coordinate value of the corresponding point is determined, and the set of critical cracking coordinate values ​​is obtained according to the coordinate values ​​of many points; in the two-dimensional coordinate system, each point in the set of critical cracking coordinate values ​​is plotted to obtain the following Figure 6 For example, in some embodiments of the present application, the failure critical line L3 is obtained by connecting two points on the boundary that is not parallel to the coordinate axis and close to the coordinate axis; or, in other embodiments of the present application, the failure critical line L3 (which may be a straight line or a curve, etc.) is obtained by connecting multiple points on the boundary that is not parallel to the coordinate axis and close to the coordinate axis.

[0171] Through the collection of points, it is found that when the edge failure coefficient value does not reach 0.7 and the failure coefficient increment of 10% shows a convergence trend, the failure coefficient boundary line L1 is drawn at the position point where the edge failure coefficient value is 0.7 (as an example of the minimum value of the edge failure coefficient value) and parallel to the Y-axis.

[0172] Likewise, a failure coefficient increment boundary line L2 is drawn at a point where the failure coefficient increment is 10% (as an example of the minimum value of the failure coefficient increment value) and parallel to the X-axis.

[0173] (3) Draw the risk critical line L4:

[0174] The failure critical line is offset on the two-dimensional coordinate system and ends at the L1 and L2 lines to obtain the risk critical line. For example, the cracking critical line is used as the baseline, the offset target percentage (for example, 30%) is used as the risk transition zone, and the risk critical line is drawn, such as Figure 4 The L4 line.

[0175] Regarding the offset amount, take 30% as an example:

[0176] Offset: Line segment P0P2 / Line segment P1P2 = 30%

[0177] It should be noted that in some other embodiments of the present application, in addition to counting the samples of the necking phenomenon, the hemming failure coefficient value of the cracking point and the failure coefficient increment after hemming can also be counted to form a coordinate point set, such as Figure 6 All NG points shown; in other embodiments of the present application, it is necessary to count the coordinate values ​​of the necking phenomenon samples, the cracking phenomenon samples, and the samples without cracking and necking, and these coordinate values ​​correspond to Figure 6 The NG points and OK points shown in the figure, where the NG points are points corresponding to the coordinate values ​​of the samples with cracking or necking (i.e., failure phenomenon), and the OK points are points corresponding to the coordinate values ​​of the samples without failure phenomenon. Figure 6 It can be found that when the failure coefficient value after hemming is lower than 0.7, no cracking occurs in the following two cases: the failure coefficient increment is greater than 25%; the failure coefficient value after hemming is greater than 0.8, but the failure coefficient increment value before and after hemming is not greater than 10%.

[0178] Therefore, the risk threshold is not biased towards L1 and L2.

[0179] (4) Determine risk areas, failure areas, and safety areas:

[0180] Failure area: Figure 6 The open area composed of L1-L3-L2

[0181] Risk area: Figure 6 The closed area composed of L1-L3-L2-L4

[0182] Safe Zone: Figure 6 The open area composed of L1-L4-L2

[0183] It should be noted that some embodiments of the present application can obtain multiple edge forming limit diagrams, that is, the drawing of edge forming limit diagrams under different conditions is completed in advance. For example, for sheet materials of different material types, grades (specific material models), and thicknesses, the corresponding edge forming limit diagrams are drawn respectively according to the above steps. For example, Figure 6The provided hemming forming limit diagram is the target hemming forming limit diagram corresponding to the object to be evaluated. The attribute parameters corresponding to this sample type are as follows: outer panel material: 6000-IH-90 with a thickness of 1 mm, inner panel material: 5000-RSS-110-U with a thickness of 1.2 mm.

[0184] It is understandable that for objects to be evaluated with different properties, it is necessary to select the hemming forming limit diagram with the same material and thickness as the inner and outer plates to evaluate the hemming forming results.

[0185] S5: Determine the risk of failure during the hemming process (for example, predict the results of failure phenomena such as hemming cracking or necking)

[0186] The specific steps for determining the risk of body hemming formability during the product development phase are as follows:

[0187] (1) Confirming the plate attribute information of the vehicle body hemming to be evaluated (as an example of the object to be evaluated), wherein the plate attribute information includes: the material type, grade (specific material model) and thickness value of the inner plate and the outer plate.

[0188] (2) The flange failure coefficient of a single piece is obtained through stamping process simulation analysis.

[0189] (3) The hemming failure coefficient value is obtained by simulating the hemming process analysis, and the difference between the hemming failure coefficient value and the flanging failure coefficient value is calculated to obtain the failure coefficient increment value.

[0190] (4) On the limit diagram, the corresponding points representing the positions of the rounded corners of the body edge are drawn, that is, the positions of the points corresponding to the edge failure coefficient values ​​and the failure increment coefficient values ​​are determined on a predefined two-dimensional coordinate system.

[0191] (5) Determine the evaluation result of the hemming forming of the vehicle body to be evaluated according to the position and the target hemming forming limit diagram, wherein the evaluation result is used to evaluate whether the hemming of the vehicle body to be evaluated has hemming forming risk, or to evaluate whether the hemming of the vehicle body to be evaluated meets the engineering design requirements. If the position of the corresponding point falls in the failure zone, it indicates that there is hemming forming failure; if the position falls in the risk zone, it indicates that there is hemming forming risk; if the position falls in the safety zone, it indicates that there is no failure in the hemming of the vehicle body to be evaluated, that is, the hemming forming property is good.

[0192] like Figure 7As shown, some embodiments of the present application provide a method for designing hemming, the method comprising: S710, obtaining a hemming forming effect corresponding to an object to be evaluated obtained by using a method such as any one of the embodiments described in the above-mentioned method for evaluating hemming forming effect; S720, adjusting the design parameter value of the object to be evaluated according to the hemming forming effect to obtain a target hemming forming parameter value of the object to be evaluated.

[0193] Please refer to Figure 8 , Figure 8 A device for evaluating the hemming forming effect provided by an embodiment of the present application is shown. It should be understood that the device is similar to the above-mentioned Figure 2 The method embodiment corresponds to the method embodiment, and can execute each step involved in the above method embodiment. The specific functions of the device can refer to the description above. To avoid repetition, the detailed description is appropriately omitted here. The device includes at least one software function module that can be stored in the memory in the form of software or firmware or solidified in the operating system of the device. The device for evaluating the hemming forming effect includes: a target hemming forming limit diagram acquisition module 210, a failure attribute value acquisition module 220, a failure attribute value corresponding point determination module 230 and a hemming forming evaluation module 240.

[0194] The target edge-wrapping forming limit diagram acquisition module 210 is configured to determine a target edge-wrapping forming limit diagram corresponding to the object to be evaluated.

[0195] The failure attribute value acquisition module 220 is configured to acquire the failure attribute value of the object to be evaluated, wherein the failure attribute value is used to characterize the strain state of the object to be evaluated during the hemming forming process.

[0196] The failure attribute value corresponding point determination module 230 determines a point corresponding to the failure attribute value in a two-dimensional coordinate system.

[0197] The hemming forming evaluation module 240 determines the hemming forming effect of the object to be evaluated according to the target area where the point is located on the target hemming forming limit diagram.

[0198] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the device described above can refer to the corresponding process in the aforementioned method, and will not be described in detail here.

[0199] Please refer to Fig. 9 , Fig. 9 A device for designing hemming provided in an embodiment of the present application is shown. It should be understood that the device is similar to the above-mentioned Figure 7The method embodiment corresponds to the method embodiment, and can execute each step involved in the above method embodiment. The specific functions of the device can refer to the description above. To avoid repetition, the detailed description is appropriately omitted here. The device includes at least one software function module that can be stored in the memory in the form of software or firmware or solidified in the operating system of the device. The device for evaluating the hemming forming effect includes: a forming evaluation result acquisition module 310 and an adjustment module 320.

[0200] The forming evaluation result acquisition module 310 is configured to obtain the hemming forming effect corresponding to the object to be evaluated obtained by using the method described in any one of the above embodiments.

[0201] The adjustment module 320 is configured to adjust the design parameter value of the object to be evaluated according to the hemming forming effect to obtain the target hemming forming parameter value of the object to be evaluated.

[0202] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the device described above can refer to the corresponding process in the aforementioned method, and will not be described in detail here.

[0203] Some embodiments of the present application provide a computer program product, including computer program instructions, which, when read and executed by a processor, execute a method in any one of the embodiments included in the method for evaluating hemming forming effect or the method for designing hemming.

[0204] like Fig.10 As shown, some embodiments of the present application provide an electronic device 400, including a memory 410, a processor 420, and a computer program stored in the memory 410 and executable on the processor 420, wherein the processor 420 can implement a method in any one of the embodiments included in the above-mentioned method for evaluating hemming forming effect or the method for designing hemming when reading and executing the program through a bus 430.

[0205] Processor 420 can process digital signals and can include various computing structures, such as complex instruction set computer structure, reduced instruction set computer structure, or a structure that implements a combination of multiple instruction sets. In some examples, processor 420 can be a microprocessor.

[0206] The memory 410 may be used to store instructions executed by the processor 420 or data related to the execution of instructions. These instructions and / or data may include code to implement some or all functions of one or more modules described in the embodiments of the present application. The processor 420 of the present embodiment may be used to execute the instructions in the memory 410 to implement Figure 2 or Figure 7The memory 410 includes a dynamic random access memory, a static random access memory, a flash memory, an optical memory or other memory known to those skilled in the art.

[0207] In several embodiments provided in the present application, it should be understood that the disclosed devices and methods can also be implemented in other ways. The device embodiments described above are merely schematic. For example, the flowcharts and block diagrams in the accompanying drawings show the possible architecture, functions and operations of the devices, methods and computer program products according to multiple embodiments of the present application. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of a code, and the module, a program segment or a part of a code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flowchart, and the combination of boxes in the block diagram and / or flowchart can be implemented with a dedicated hardware-based system that performs a specified function or action, or can be implemented with a combination of dedicated hardware and computer instructions.

[0208] In addition, the functional modules in the various embodiments of the present application may be integrated together to form an independent part, or each module may exist separately, or two or more modules may be integrated to form an independent part.

[0209] If the functions are implemented in the form of software function modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0210] The above description is only an embodiment of the present application and is not intended to limit the scope of protection of the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.

[0211] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

[0212] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

Claims

1. A method for evaluating the hemming forming effect, characterized in that: The method comprises: Determine a target hemming forming limit diagram corresponding to the object to be evaluated; Acquiring a failure attribute value of the object to be evaluated, wherein the failure attribute value is used to characterize the strain state of the object to be evaluated during the hemming forming process; Determining a point corresponding to the failure attribute value on a two-dimensional coordinate system; The hemming forming effect of the object to be evaluated is determined according to the target area where the point is located on the target hemming forming limit diagram.

2. The method according to claim 1, characterized in that The failure attribute value includes a hemming failure coefficient value and a failure coefficient increment value.

3. The method according to claim 1 or 2, characterized in that The target hemming forming limit diagram includes a plurality of regions with different forming effects, wherein the plurality of regions with different forming effects include: a failure region and a non-failure region, wherein the non-failure region includes: a risk region and a safety region, wherein: The step of determining the forming effect of the object to be evaluated according to the target area where the point is located on the target edge forming limit diagram comprises: If the point is located in the failure zone, it is confirmed that the object to be evaluated has edge failure; If the point is located in the risk area, it is confirmed that the object to be evaluated has a risk of hemming failure; If the point is located in the safety zone, it is confirmed that there is no risk of hemming failure for the object to be evaluated.

4. The method according to claim 1, characterized in that The step of determining a target edge forming limit diagram corresponding to the object to be evaluated comprises: Collecting samples, wherein the samples are hemmed parts; Obtaining sample failure attribute values ​​of at least part of the samples, wherein the sample failure attribute values ​​include: an edge failure coefficient value and a failure coefficient increment value; A sample failure attribute value of a sample matching the object to be evaluated is obtained according to the sample failure attribute value, and the target hemming forming limit diagram is obtained according to the sample failure attribute value of the sample matching the object to be evaluated.

5. The method according to claim 2 or 4, characterized in that The failure coefficient increment value is determined by the hemming failure coefficient value and the flanging failure coefficient value, and the flanging failure coefficient value is determined by calculating the failure coefficient of the stamping process.

6. The method according to claim 4, characterized in that The obtaining of sample failure attribute values ​​of at least some of the samples includes: Determine a sample with failure phenomenon among the samples as a target sample; A sample failure attribute value of the target sample is obtained, wherein the sample failure attribute value includes an edge failure coefficient value and a failure coefficient increment value of the target sample.

7. The method according to claim 4, characterized in that The step of obtaining the sample failure attribute value of the sample matching the object to be evaluated according to the sample failure attribute value and obtaining the target edge forming limit diagram according to the sample failure attribute value of the sample matching the object to be evaluated comprises: Using the sample failure attribute value of the sample matching the object to be evaluated as the target coordinate value; In the two-dimensional coordinate system, determining a failure critical line, a failure coefficient boundary line, and a failure coefficient increment boundary line according to the target coordinate value; The plane corresponding to the two-dimensional coordinate system is divided into a plurality of regions with different forming effects based at least on the failure critical line, the failure coefficient boundary line and the failure coefficient increment boundary line, and the target hemming forming limit diagram is obtained according to the plurality of regions with different forming effects.

8. The method according to claim 7, characterized in that The matching samples are samples with failure phenomena, wherein: Determining the failure critical line according to the target coordinate value includes: The failure critical line is determined according to a point on the boundary of the area covered by the target coordinate value on the plane.

9. The method according to claim 8, characterized in that The step of determining the failure critical line according to a point on the boundary of the area covered by the target coordinate value on the plane comprises: The failure critical line is obtained by connecting at least two points on the boundary.

10. The method according to claim 7, characterized in that The matching samples include first-type matching samples with failure phenomena and second-type matching samples without failure phenomena, wherein: Determining the failure critical line according to the target coordinate value includes: Obtaining a failed sample area by determining target coordinate values ​​of the first type of matching samples on the plane; Obtaining a non-failed sample area by determining target coordinate values ​​of the second type of matching samples on the plane; The failure critical line is determined at a boundary between the failure sample area and the non-failure sample area.

11. The method according to claim 10, characterized in that The step of determining the failure critical line at the boundary between the failure sample area and the non-failure sample area comprises: The failure critical line is obtained by connecting at least two points of the junction.

12. The method according to claim 7, characterized in that Determining the failure coefficient boundary line and the failure coefficient increment boundary line according to the target coordinate value includes: Determine a line passing through a failure coefficient boundary value and parallel to the first coordinate axis as the failure coefficient boundary line, wherein the failure coefficient boundary value is obtained by determining a maximum value of an edge failure coefficient value corresponding to a first type of matching sample, wherein the first type of matching sample is a matching sample with a failure phenomenon; A line passing through the failure coefficient increment boundary value and parallel to the second coordinate axis is determined as the failure coefficient increment boundary line, wherein the failure coefficient increment boundary value is obtained by determining the maximum value of the failure coefficient increment value corresponding to the first type of matching samples.

13. The method according to any one of claims 7 to 12, characterized in that The method of dividing the plane corresponding to the two-dimensional coordinate system into the plurality of regions with different forming effects based at least on the failure critical line, the failure coefficient boundary line, and the failure coefficient increment boundary line, and obtaining the target hemming forming limit diagram according to the plurality of regions with different forming effects includes: The two open areas divided by the failure critical line, the failure coefficient boundary line and the failure coefficient increment boundary line on the plane are respectively used as failure areas and non-failure areas; The target hemming forming limit diagram is obtained according to the failure area and the non-failure area.

14. The method according to claim 7, characterized in that The method of dividing the plane corresponding to the two-dimensional coordinate system into the plurality of regions with different forming effects based at least on the failure critical line, the failure coefficient boundary line, and the failure coefficient increment boundary line, and obtaining the target hemming forming limit diagram according to the plurality of regions with different forming effects includes: Obtaining a risk critical line according to the failure critical line, wherein the risk critical line is used to divide an area with failure risk on a plane corresponding to the two-dimensional coordinate system; The target forming limit diagram is obtained by dividing the plane into a failure zone, a risk zone and a safety zone based on the failure critical line, the risk critical line, the failure coefficient boundary line and the failure coefficient increment boundary line.

15. The method according to claim 14, characterized in that The step of obtaining the target forming limit diagram by dividing the plane into a failure zone, a risk zone, and a safety zone based on the failure critical line, the risk critical line, the failure coefficient boundary line, and the failure coefficient increment boundary line comprises: determining an open area defined by the failure coefficient boundary line, the failure critical line, and the failure coefficient increment boundary line as the failure zone; Determine a closed area defined by the failure coefficient boundary line, the failure critical line, the risk critical line, and the failure coefficient increment boundary line as the risk area; Determining an open area defined by the failure coefficient boundary line, the risk critical line, and the failure coefficient increment boundary line as the safety zone; The target forming limit diagram is obtained according to the failure zone, the risk zone and the safety zone.

16. The method according to claim 14, characterized in that The step of obtaining a risk critical line according to the failure critical line includes: The failure critical line is offset processed according to the offset amount to obtain the risk critical line, wherein the offset amount is the ratio of the first distance to the second distance, the first distance is the distance from the intersection of the failure coefficient boundary line and the failure coefficient increment boundary line to the risk critical line, and the second distance is the distance from the intersection of the failure coefficient boundary line and the failure coefficient increment boundary line to the failure critical line.

17. A method for designing hemming, characterized in that: The method comprises: Obtaining a hemming forming effect corresponding to the object to be evaluated obtained by the method according to any one of claims 1 to 16; The design parameter values ​​of the object to be evaluated are adjusted according to the hemming forming effect to obtain the target hemming forming parameter values ​​of the object to be evaluated.

18. A computer program product, characterized in that The method comprises computer program instructions, which can implement the method according to any one of claims 1 to 17 when read and executed by a processor.

19. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the method according to any one of claims 1 to 17 can be implemented.

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