Method for characterizing anisotropic yield behavior of metal plate

Abstract

The invention provides a characterization method for anisotropic yield behavior of a metal plate. The characterization method comprises the following steps: carrying out a mechanical test on a to-be-characterized metal plate; setting rotation angles alpha and beta of the polar coordinate system to be 0 degree; calibrating a yield criterion f1; calculating the yield stress # imgabs0 # calibration yield criterion f2 of the to-be-represented metal plate corresponding to the alpha and beta of the current polar coordinate system; calculating the yield stress of the to-be-represented metal plate corresponding to the alpha and beta of the current polar coordinate system # imgabs1 #, and calculating the stress triaxial degree eta corresponding to the alpha and beta of the current polar coordinate system # imgabs1 #; calculating a weight factor # imgabs2 corresponding to the current eta; calculating yield stress sigma s corresponding to alpha and beta of a polar coordinate system; sigma s is the obtained yield stress of the metal plate to be represented; enabling alpha to be equal to alpha + delta alpha, returning to the step of calibrating f1 until the current value of alpha is not less than 180 degrees, enabling alpha to be equal to 0 degree, and executing the next step; and enabling beta to be equal to beta + delta beta, returning to the step of calibrating f1 until the current value of beta is not less than 360 degrees, and predicting each yield stress sigma s corresponding to different positions on the yield surface of the to-be-represented metal plate. According to the method, the anisotropic yield behavior of the metal plate in the plastic deformation process can be simply and accurately represented.

Description

Technical Field

[0001] The present invention relates to the technical field of prediction of anisotropic yield behavior of metal plates, and in particular to a method for characterizing the anisotropic yield behavior of metal plates. Background Art

[0002] High-performance sheet metal is widely used in the automotive industry, which can not only reduce fuel consumption and CO2 emissions, but also increase the collision safety, recyclability and braking performance of automobiles. However, after undergoing a complex thermal processing history, sheet metal is usually accompanied by significant anisotropic yield behavior. In addition, during the plastic forming process, sheet metal is often subjected to the combined effects of uniaxial tension, equibiaxial tension, near-plane strain and simple shear load, which makes it difficult to characterize the anisotropic yield behavior of sheet metal with high precision using existing technologies.

[0003] At present, when evaluating the geometry and forming process of components through some existing commercial finite element analysis software, the embedded yield criteria can only predict the uniaxial and equibiaxial tensile yield stresses, and it is usually difficult to provide high-precision characterization results for plastic deformation behaviors dominated by near-plane strains and simple shear loads. In order to overcome this problem, some yield criteria with many anisotropic coefficients have been developed. However, the form of these yield criteria is usually too complicated, and the calibration strategy and partial derivative information are difficult to effectively formulate and obtain. Therefore, without increasing the complexity of the yield criterion, developing a simple, high-precision and high-efficiency characterization method will help to promote the in-depth application of virtual manufacturing technology in the modern automotive industry. Summary of the invention

[0004] The present invention aims to solve the technical problem that the existing technology cannot simply and accurately characterize the anisotropic yield behavior of metal plates during plastic deformation.

[0005] To this end, the purpose of the present invention is to provide a method for characterizing the anisotropic yield behavior of metal sheets.

[0006] In order to achieve the above-mentioned purpose, the technical solution of the present invention provides a method for characterizing the anisotropic yield behavior of a metal sheet, and the method comprises: step S1: conducting a mechanical test on the metal sheet to be characterized to obtain test data under uniaxial tension, equibiaxial tension, near-plane strain and simple shear load; step S2: setting the rotation angles α and β of the polar coordinate system to be equal to 0° respectively; step S3: calibrating the first selected yield criterion f1 based on the test data under the uniaxial tension and equibiaxial tension loads; step S4: calculating the yield stress of the metal sheet to be characterized corresponding to the rotation angles α and β of the current polar coordinate system based on the calibrated first selected yield criterion f1. Step S5: based on the test data under the near-plane strain and simple shear load, calibrate the second selected yield criterion f2; Step S6: based on the calibrated second selected yield criterion f2, calculate the yield stress of the metal sheet to be characterized corresponding to the rotation angles α and β of the current polar coordinate system Step S7: Calculate the stress triaxiality η corresponding to the rotation angles α and β of the current polar coordinate system; Step S8: Calculate the weight factor corresponding to the current stress triaxiality η Step S9: Based on the current weight factor Yield stress σ f1 and σ f2 , calculate the yield stress σ corresponding to the rotation angles α and β of the polar coordinate system s ; Wherein, the yield stress σ s The yield stress of the metal sheet to be characterized is obtained; step S10: let α = α + Δα to update the rotation angle α of the polar coordinate system, return to step S3, until the current value of α is not less than 180°, let α = 0° and execute step S11; wherein, the value ranges of α and Δα are both [0, 180°]; step S11: let β = β + Δβ to update the rotation angle β of the polar coordinate system, return to step S3, until the current value of β is not less than 360°, then the yield stresses σ corresponding to different positions on the yield surface of the metal sheet to be characterized can be predicted. s ; Among them, the value range of β and Δβ is [0, 360°].

[0007] Preferably, the first selected yield criterion f1 is: an exponential yield criterion, a coupled yield criterion or a yield criterion with a shape control factor; the second selected yield criterion f2 is: an exponential yield criterion, a coupled yield criterion or a yield criterion with a shape control factor.

[0008] Preferably, the first selected yield criterion f1 and the second selected yield criterion f2 are the same or different.

[0009] Preferably, the step S7 specifically comprises: calculating the stress triaxiality η corresponding to the rotation angles α and β of the current polar coordinate system by a first preset formula; wherein the expression of the first preset formula is:

[0010]

[0011] In formula (1), σ xx =cosβcosα,σ yy =cosβsinα,σ xy = sinβ;σ xx , σ yy and σ xy represents the in-plane stress components of the Cauchy stress tensor.

[0012] Preferably, the step S8 specifically includes: calculating the weight factor corresponding to the current stress triaxiality η by a second preset formula The expression of the second preset formula is:

[0013]

[0014] Preferably, the step S9 specifically includes: using a third preset formula, the current weight factor Yield stress and Calculate the yield stress σ of the metal sheet corresponding to the rotation angles α and β of the polar coordinate system s ;

[0015] Wherein, the expression of the third preset formula is:

[0016]

[0017] Preferably, the characterization method is implemented by software with a compiling function.

[0018] Beneficial effects of the present invention:

[0019] (1) The characterization method of the anisotropic yield behavior of metal plates provided by the present invention can accurately predict the yield stress of metal plates under uniaxial tension, equibiaxial tension, near-plane strain and simple shear load.

[0020] (2) The method for characterizing the anisotropic yield behavior of metal plates provided by the present invention can obtain high-precision characterization results by integrating the yield stress of the metal plates calculated by only two simple yield criteria. While significantly improving the characterization accuracy of the anisotropic yield behavior of the metal plates, it avoids the complex development process of increasing the anisotropy coefficient to improve the characterization accuracy of the yield criterion.

[0021] (3) The characterization method of the anisotropic yield behavior of metal sheets provided by the present invention has the obvious advantage of user-friendliness compared with the existing yield criterion development technology. Specifically, even non-professionals who are not in this field can skillfully use the present method to characterize the anisotropic yield behavior of metal sheets with high precision.

[0022] Additional aspects and advantages of the invention will become apparent from the following description, or may be learned by practice of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic flow chart showing a method for characterizing anisotropic yield behavior of a metal sheet according to an embodiment of the present invention;

[0024] Figure 2 A schematic diagram showing a three-dimensional yield surface predicted for a DP980 metal sheet using the high-precision characterization method for anisotropic yield behavior of a metal sheet according to an embodiment of the present invention;

[0025] Figure 3 A schematic diagram showing the yield stress calculated using the high-precision characterization method for anisotropic yield behavior of the metal sheet and two selected yield criteria according to one embodiment of the present invention is shown;

[0026] Figure 4 A schematic diagram of a curve showing a weight factor according to an embodiment of the present invention changing with stress triaxiality η;

[0027] Figure 5 A schematic diagram showing the normal plane yield trajectory predicted for a DP980 metal sheet using the high-precision characterization method for anisotropic yield behavior of a metal sheet according to an embodiment of the present invention, and comparing it with test data under uniaxial tension, equibiaxial tension, near-plane strain and simple shear load;

[0028] Figure 6 A schematic diagram showing an embodiment of the present invention using the high-precision characterization method for the anisotropic yield behavior of metal sheets to predict the diagonal plane yield trajectory of DP980 metal sheet, and comparing it with test data under uniaxial tension, equibiaxial tension, near-plane strain and simple shear load. DETAILED DESCRIPTION

[0029] In order to more clearly understand the above-mentioned objectives, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0030] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0031] Figure 1 A schematic flow chart of a method for characterizing anisotropic yield behavior of a metal sheet according to an embodiment of the present invention is shown. Figure 1 As shown, the characterization method comprises:

[0032] Step S1: Conduct mechanical tests on the metal sheet to be characterized to obtain test data under uniaxial tension, equibiaxial tension, near-plane strain and simple shear load;

[0033] Step S2: respectively setting the rotation angles α and β of the polar coordinate system to be equal to 0°;

[0034] Step S3: calibrating the first selected yield criterion f1 based on the test data under uniaxial tension and equibiaxial tension loads;

[0035] Step S4: Based on the first selected yield criterion f1 after calibration, calculate the yield stress σ of the metal sheet to be characterized corresponding to the rotation angles α and β of the current polar coordinate system f1 ;

[0036] Step S5: calibrating the second selected yield criterion f2 based on the test data under near-plane strain and simple shear load;

[0037] Step S6: Based on the calibrated second selected yield criterion f2, calculate the yield stress σ of the metal sheet to be characterized corresponding to the rotation angles α and β of the current polar coordinate system f2 ;

[0038] Step S7: Calculate the stress triaxiality η corresponding to the rotation angles α and β of the current polar coordinate system;

[0039] Step S8: Calculate the weight factor corresponding to the current stress triaxiality η

[0040] Step S9: Based on the current weight factor Yield stress σ f1 and σ f2 , calculate the yield stress σ corresponding to the rotation angles α and β of the polar coordinate system s ;

[0041] Step S10: Set α=α+Δα to update the rotation angle α of the polar coordinate system, and return to step S3 until the current value of α is not less than 180°, then set α=0° and execute step S11;

[0042] Step S11: Let β = β + Δβ to update the rotation angle β of the polar coordinate system, and return to step S3 until the current value of β is not less than 360°, then the yield stresses σ corresponding to different positions on the yield surface of the metal sheet to be characterized can be predicted. s .

[0043] In this embodiment, the yield stress σ s is the yield stress of the metal sheet to be characterized.

[0044] In this embodiment, the value range of Δα is [0, 180°]; the value range of Δβ is [0, 360°]. The smaller the values ​​of Δα and Δβ are, the more yield points are obtained on the yield surface. The values ​​of Δα and Δβ have nothing to do with the prediction accuracy and are only used to control the obtained yield stress σ s The number and location of on the three-dimensional yield surface.

[0045] In a specific embodiment, when conducting a mechanical test on a metal plate to be characterized, the selection of the sample loading direction needs to be determined by considering both the anisotropy degree of the metal plate to be characterized and the calibration method of the yield criterion.

[0046] In this embodiment, the characterization method of the anisotropic yield behavior of the metal sheet provided by the present invention can accurately predict the yield stress of the metal sheet under uniaxial tension, equibiaxial tension, near-plane strain and simple shear load.

[0047] In this embodiment, the method for characterizing the anisotropic yield behavior of metal plates provided by the present invention can obtain high-precision characterization results by only integrating the yield stress of the metal plates calculated by two simple yield criteria. While significantly improving the characterization accuracy of the anisotropic yield behavior of the metal plates, it avoids the complex development process of increasing the anisotropy coefficient to improve the characterization accuracy of the yield criterion.

[0048] In this embodiment, the characterization method of the anisotropic yield behavior of the metal sheet provided by the present invention has the obvious advantage of user-friendliness compared with the existing yield criterion development technology. Specifically, even non-professionals who are not in this field can skillfully use the method to perform high-precision characterization of the anisotropic yield behavior of the metal sheet.

[0049] In one embodiment of the present invention, the first selected yield criterion f1 is: an exponential yield criterion, a coupled yield criterion or a yield criterion with a shape control factor; the second selected yield criterion f2 is: an exponential yield criterion, a coupled yield criterion or a yield criterion with a shape control factor.

[0050] In one embodiment of the present invention, the first selected yield criterion f1 and the second selected yield criterion f2 are the same or different.

[0051] In one embodiment of the present invention, step S7 specifically includes: calculating the stress triaxiality η corresponding to the rotation angles α and β of the current polar coordinate system by a first preset formula; wherein the expression of the first preset formula is:

[0052]

[0053] In formula (1), σ xx =cosβcosα,σ yy =cosβsinα,σ xy = sinβ;σ xx , σ yy and σ xy represents the in-plane stress components of the Cauchy stress tensor.

[0054] In one embodiment of the present invention, step S8 specifically includes: calculating the weight factor corresponding to the current stress triaxiality η by a second preset formula: The expression of the second preset formula is:

[0055]

[0056] In one embodiment of the present invention, step S9 specifically includes: using a third preset formula, a current weight factor Yield stress σ f1 and σ f2 , calculate the yield stress σ of the metal sheet corresponding to the rotation angles α and β of the polar coordinate system s ; Wherein, the expression of the third preset formula is:

[0057]

[0058] In one embodiment of the present invention, the characterization method is implemented by software with a compiling function.

[0059] The technical solution of the present invention will be demonstrated with a specific embodiment below.

[0060] Combination Figure 2 , showing that the yield stress of DP980 metal sheet is characterized by using a characterization method of anisotropic yield behavior of metal sheet provided by the present invention. The specific implementation steps of the characterization method are as follows:

[0061] Step 1: Perform uniaxial tension, equibiaxial tension, near-plane strain tension and simple shear tests on the DP980 metal sheet to obtain uniaxial tension yield stress at 0°, 45° and 90° along the rolling direction, equibiaxial tension yield stress, near-plane strain tension yield stress at 0°, 45° and 90° along the rolling direction, and simple shear yield stress;

[0062] Step 2: Set α and β to 0°, where α and β represent the two rotation angles of the polar coordinate system;

[0063] Step 3: Use the uniaxial tension and equibiaxial tension test data of step 1 to calibrate the Barlat89 yield criterion;

[0064] Step 4: Calculate the yield stress of the DP980 metal sheet at two rotation angles based on the Barlat89 yield criterion calibrated in step 3

[0065] Step 5: Use the near-plane strain tension and simple shear test data from step 1 to calibrate the Barlat89 yield criterion;

[0066] Step 6: Calculate the yield stress of the DP980 metal sheet at two rotation angles based on the Barlat89 yield criterion calibrated in step 5

[0067] Step 7: Calculate the stress triaxiality η corresponding to the two rotation angles. The stress triaxiality η is expressed as:

[0068]

[0069] In formula (1), σ xx =cosβcosα,σ yy =cosβsinα,σ xy = sinβ;σ xx , σ yy and σ xy represents the in-plane stress components of the Cauchy stress tensor;

[0070] Step 8: Calculate weight factor based on stress triaxiality η Weight Factor The display expression is:

[0071]

[0072] Step 9: Pass Integration and Then we get σ s , σ s The display expression is:

[0073]

[0074] In formula (3), σ s It represents the yield stress of the DP980 metal sheet corresponding to the two rotation angles obtained in this specific embodiment;

[0075] Step 10: increase α by Δα, and re-execute steps 3 to 9 until the current value of α is not less than 180°, set α=0° and execute step S11; wherein the value range of Δα is [0, 180°]; the size of Δα here has nothing to do with the characterization accuracy, and is only used to control the number of yield points on the yield surface. In this specific embodiment, Δα is set to 1;

[0076] Step 11: Increase β by Δβ, and re-execute steps 3 to 10 until the current value of β is not less than 360°. Then, the yield stresses σ corresponding to different positions on the yield surface of the metal sheet to be characterized can be predicted. s; Among them, the value range of Δβ is [0, 360°]; the size of Δβ here has nothing to do with the characterization accuracy and is only used to control the number of yield points on the yield surface. In this specific embodiment, Δβ is set to 1.

[0077] In this specific embodiment, the present invention predicts the yield stress of the DP980 metal sheet under different loading paths on the yield surface, such as Figure 2 As shown. xx , σ yy and σ xy represent the in-plane stress components of the Cauchy stress tensor, respectively.

[0078] In this specific embodiment, the weight factor Integrate the yield stresses calculated from two selected yield criteria and The yield stress σ of the metal sheet predicted by the present invention is obtained s Among them, the weight factor The expression of formula (1) and yield stress σ s The expression of is formula (2).

[0079] Figure 3 The yield stress calculated for the first selected yield criterion f1 calibrated with uniaxial and equibiaxial tension test data is shown. Yield stress calculated from the second selected yield criterion f2 calibrated with near-plane strain and simple shear test data And through the current weight factor Integration and The obtained σ s .like Figure 3 As shown, it can be found that the σ calculated by the present invention s The ability of the yield criterion f1 to accurately predict the uniaxial and equibiaxial tensile test data is retained, while the ability of the yield criterion f2 to accurately characterize the near-plane strain and simple shear test data is inherited, which is attributed to the contribution of equations (1) and (2). The rationality of the function structure of equations (1) and (2) is explained below:

[0080] First, since the yield criterion f1 provides zero error prediction accuracy under uniaxial and equibiaxial tensile stress states, the formula (1) provided by the present invention calculates the yield criterion f1 under uniaxial and equibiaxial tensile stress states. is equal to 1, such as Figure 4 As shown. Substituting into formula (2) we can get That is, the present invention can also predict the yield stress of metal sheets with zero error under uniaxial and equibiaxial tensile stress states. Secondly, since the yield criterion f2 provides a zero error characterization result under near plane strain and simple shear stress states, the yield stress calculated by the formula (1) provided by the present invention under near plane strain and simple shear stress states is Should be equal to 0, such as Figure 4 As shown. Substituting into formula (2) we can get That is, the present invention can also predict the yield stress of metal sheets with zero error under near-plane strain and simple shear stress conditions. Based on this, formula (2) is used to combine and Thus, accurate prediction of uniaxial tension, equibiaxial tension, near-plane strain and simple shear stress states is achieved. s The function expression is reasonable.

[0081] In summary, the weight factor calculated by formula (1) It should be equal to 1 in uniaxial and equibiaxial tensile stress states, and should be equal to 0 in near-plane strain tension and simple shear stress states. Also, since the yield criterion is tension-compression symmetric, the weight factor The curve with stress triaxiality η should be symmetric about η = 0. Finally, the continuity of the yield locus of sheet metal is an inherent property of the material, so the weight factor It should also be continuous. Weight factor Can meet all of the above conditions, such as Figure 4 As shown, the weight factor used in the present invention is The functional form of is reasonable.

[0082] Furthermore, in order to better reflect the difference between the present invention and the existing method, a comparative example 1 and a comparative example 2 are used below to demonstrate the advantages of the technical solution of the present invention.

[0083] Comparative Example 1: Figure 5 A schematic diagram showing the normal plane yield trajectory predicted for DP980 metal sheet using the high-precision characterization method for anisotropic yield behavior of metal sheet according to an embodiment of the present invention, and comparing it with the test data under uniaxial tension, equibiaxial tension, near-plane strain and simple shear load. In this comparative example 1, the first selected yield criterion f1 and the second selected yield criterion f2 are the Hill48 yield criterion and the Barlat89 yield criterion, respectively.

[0084] Figure 5The following information can be reflected in it: (1) The Hill48 yield criterion, which is the most widely used in the industry, only accurately characterizes the yield stress of DP980 metal sheet under uniaxial and equibiaxial tensile stress states, and the yield stress predicted under near-plane strain stress state has a significant deviation from the experimental data; (2) The Barlat89 yield criterion embedded in commercial finite element analysis software such as LS-Dyna, ABAQUS, AUTOFORM and OPTRIS provides a significant error for DP980 metal sheet under simple shear stress state; (3) The present invention accurately characterizes the yield stress of DP980 metal sheet under uniaxial tension, equibiaxial tension, near-plane strain and simple shear stress states.

[0085] The comparison results show that: on the basis of maintaining the simplicity of the yield criterion, the present invention accurately predicts the yield stress of DP980 metal sheet under uniaxial tension, equibiaxial tension, near-plane strain and simple shear stress states. Compared with the widely used Hill48 and Barlat89 yield criteria, the present invention provides a higher characterization accuracy for the normal plane yield locus of DP980 metal sheet.

[0086] Comparative Example 2: Figure 6 A schematic diagram showing the predicted diagonal plane yield trajectory of DP980 metal sheet using the high-precision characterization method for anisotropic yield behavior of metal sheet according to an embodiment of the present invention and comparing it with the test data under uniaxial tension, equibiaxial tension, near-plane strain and simple shear load. In this comparative example 2, the first selected yield criterion f1 and the second selected yield criterion f2 are the Hill48 yield criterion and the Barlat89 yield criterion, respectively.

[0087] Figure 6 The following information can be reflected in the results: (1) The yield stress predicted by the Hill48 yield criterion, which is the most widely used in the industry, under the near-plane strain stress state has a significant deviation from the experimental data; (2) The Barlat89 yield criterion embedded in the commercial finite element analysis software LS-Dyna, ABAQUS, AUTOFORM and OPTRIS provides a significant error for the DP980 metal sheet under the simple shear stress state; (3) The present invention accurately characterizes the yield stress of the DP980 metal sheet under uniaxial tension, equibiaxial tension, near-plane strain and simple shear stress states.

[0088] The comparison results show that: on the basis of maintaining the simplicity of the yield criterion, the present invention accurately predicts the yield stress of DP980 metal sheet under uniaxial tension, equibiaxial tension, near-plane strain and simple shear stress states. Compared with the widely used Hill48 and Barlat89 yield criteria, the present invention provides a higher characterization accuracy for the diagonal plane yield locus of DP980 metal sheet.

[0089] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for characterizing the anisotropic yield behavior of a metal sheet, characterized in that: include: Step S1: Conduct mechanical tests on the metal sheet to be characterized to obtain test data under uniaxial tension, equibiaxial tension, near-plane strain and simple shear load; Step S2: respectively setting the rotation angles α and β of the polar coordinate system to be equal to 0°; Step S3: calibrating the first selected yield criterion f1 based on the test data under the uniaxial tension and equibiaxial tension loads; Step S4: Based on the first selected yield criterion f1 after calibration, calculate the yield stress σ of the metal sheet to be characterized corresponding to the rotation angles α and β of the current polar coordinate system f1 ; Step S5: calibrating a second selected yield criterion f2 based on the test data under the near-plane strain and simple shear load; Step S6: Based on the calibrated second selected yield criterion f2, calculate the yield stress σ of the metal sheet to be characterized corresponding to the rotation angles α and β of the current polar coordinate system f2 ; Step S7: Calculate the stress triaxiality η corresponding to the rotation angles α and β of the current polar coordinate system; Step S8: Calculate the weight factor corresponding to the current stress triaxiality η Step S9: Based on the current weight factor Yield stress and Calculate the yield stress σ corresponding to the rotation angles α and β of the polar coordinate system s ; Wherein, the yield stress σ s The yield stress of the metal sheet to be characterized is obtained; Step S10: Set α = α + Δα to update the rotation angle α of the polar coordinate system, return to step S3, until the current value of α is not less than 180°, set α = 0° and execute step S11; wherein the value ranges of α and Δα are both ° [0，180]； Step S11: Let β = β + Δβ to update the rotation angle β of the polar coordinate system, and return to step S3 until the current value of β is not less than 360°, then the yield stresses σ corresponding to different positions on the yield surface of the metal sheet to be characterized can be predicted. s ; Among them, the value range of β and Δβ is [0, 360°].

2. The method for characterizing anisotropic yield behavior of metal sheet according to claim 1, characterized in that: The first selected yield criterion f1 is: an exponential yield criterion, a coupled yield criterion or a yield criterion with a shape control factor; The second selected yield criterion f2 is: an exponential yield criterion, a coupled yield criterion or a yield criterion with a shape control factor.

3. The method for characterizing anisotropic yield behavior of metal sheet according to claim 1, characterized in that: The first selected yield criterion f1 and the second selected yield criterion f2 are the same or different.

4. The method for characterizing anisotropic yield behavior of metal sheet according to claim 1, characterized in that: The step S7 specifically includes: calculating the stress triaxiality η corresponding to the rotation angles α and β of the current polar coordinate system by a first preset formula; The expression of the first preset formula is: In formula (1), σ xx =cosβcosα,σ yy =cosβsinα,σ xy = sinβ;σ xx , σ yy and σ xy represents the in-plane stress components of the Cauchy stress tensor.

5. The method for characterizing anisotropic yield behavior of metal sheet according to claim 1, characterized in that: The step S8 specifically includes: calculating the weight factor corresponding to the current stress triaxiality η by a second preset formula The expression of the second preset formula is:

6. The method for characterizing anisotropic yield behavior of metal sheet according to claim 1, characterized in that: The step S9 specifically includes: using the third preset formula, the current weight factor Yield stress and Calculate the yield stress σ of the metal sheet corresponding to the rotation angles α and β of the polar coordinate system s ; Wherein, the expression of the third preset formula is:

7. The method for characterizing the anisotropic yield behavior of a metal sheet according to any one of claims 1 to 6, characterized in that: The characterization method is implemented by software with a compiling function.

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