Crystal plasticity finite element mesh mapping method based on MATLAB

Abstract

The invention discloses a crystal plasticity finite element mesh mapping method based on MATLAB. The method comprises the steps that S1, a complete machining procedure is divided into a plurality of continuous small-deformation machining steps; s2, establishing a first state model A in the ABAQUS according to the first processing step, generating an ABAQUS output INP-A file, and outputting a state variable SDV-A of the model in the first processing step; s3, establishing a second state model B according to the second processing step, and generating an INP-B file; s4, reading SDV-A data of the first state model A by using MATLAB, performing data conversion on the SDV-A, constructing a crystal plasticity constitutive model of the second state model B by using the converted SDV-A data, and realizing material endowing by modifying an INP-B file; the problem of calculation interruption or result distortion caused by serious distortion of a finite element grid in a large deformation process can be solved; continuous simulation of the multi-pass machining process is achieved, and the transmission precision of physical quantities among different machining steps is ensured.

Description

Technical Field

[0001] The invention belongs to the field of computational materials science and engineering, and specifically relates to a crystal plasticity finite element mesh mapping method based on MATLAB. Background Art

[0002] In the field of computational materials science and engineering, the crystal plasticity finite element method (CPFEM) has significantly improved the accuracy of metal plastic deformation simulation by integrating the crystal plasticity constitutive model into the finite element framework. It can accurately predict the microstructural evolution of materials under complex stress states (such as grain orientation rotation, dislocation slip, etc.). However, in metal processing processes involving large deformations (such as rolling, extrusion, and stretching), the finite element mesh is prone to severe distortion, resulting in computational divergence or distorted results. The mesh remapping method provided by traditional CAE analysis software (such as ABAQUS) relies on interpolation and extrapolation, which is not only prone to introducing errors, but also makes it difficult to maintain the mesh quality of multi-stage deformations in a single model, resulting in a decrease in the accuracy and reliability of the simulation results, and cannot meet the needs of high-precision engineering analysis. Summary of the Invention

[0003] Purpose of the invention: In order to overcome the deficiencies in the prior art, the present invention provides a MATLAB-based crystal plasticity finite element mesh mapping method, which can solve the problem that the finite element mesh is prone to severe distortion during large deformation processes, resulting in calculation interruption or distorted results; provides a crystal plasticity finite element mesh mapping method that can accurately transfer the material deformation history; realizes the continuous simulation of multi-pass machining processes, and ensures the accuracy of the transmission of physical quantities between different machining steps.

[0004] Technical solution: To achieve the above purpose, the present invention provides a crystal plasticity finite element mesh mapping method based on MATLAB, comprising the following steps:

[0005] Step S1: Divide the processing steps into several consecutive small deformation processing steps;

[0006] Step S2: Constructing a crystal plastic constitutive model, establishing a first state model A in ABAQUS according to the first processing step, generating an ABAQUS output INP-A file, and outputting the state variable SDV-A of the model in the first processing step;

[0007] Step S3: Establish a second state model B according to the second processing step and generate an INP-B file;

[0008] Step S4: Use MATLAB to read the SDV-A data of the first state model A and perform data conversion on the SDV-A. Use the converted SDV-A data to construct the crystal plasticity constitutive model of the second state model B, and implement material assignment by modifying the INP-B file, thereby achieving mesh remapping from the first state model A to the second state model B.

[0009] Furthermore, step S2 includes the following steps:

[0010] Step S2.1: Use the UMAT subroutine of ABAQUS to construct a crystal plasticity mechanics model that reflects the initial state of the material;

[0011] Step S2.2: Constructing a model framework of the first state model A based on the small deformation of the first processing step;

[0012] Step S2.3: Implement grid discretization processing, set model parameters, and complete the construction of the first state model A;

[0013] Step S2.4: Export the first state model A as an ABAQUS-specific INP-A file;

[0014] Step S2.5: Perform material simulation calculations on the first state model A according to INP-A and generate an SDV-A data file.

[0015] Furthermore, step S3 includes the following steps:

[0016] Step S3.1: Constructing a model framework of the second state model B based on the small deformation of the second processing step;

[0017] Step S3.2: Implement grid discretization processing, set model parameters, and complete the construction of the second state model B;

[0018] Step S3.3: Export the second state model B as an ABAQUS-specific INP-B file.

[0019] Furthermore, step S4 includes the following steps:

[0020] Step S4.1: Reading the SDV-A data of the first state model A through the MATLAB program;

[0021] Step S4.2: Extract the first slip system A based on the SDV-A file information. Based on the grain orientation of the material after the first processing step in the SDV-A, construct the first coordinate system A to describe the spatial orientation of the slip system A.

[0022] Step S4.3: Setting the inherent slip system of the material as the second slip system B, and constructing a second coordinate system B about the second slip system B based on the inherent slip system of the material;

[0023] Step S4.4: Compare and analyze the spatial distribution characteristics of the grains in the first slip system A and the second slip system B, and then determine the rotation matrix R of the material grain orientation relative to the initial state after the first processing step, and obtain the grain orientation after the deformation in the first processing step;

[0024] Step S4.5: Based on the grain orientation obtained in step S4.4, construct the crystal plastic constitutive model required for the second state model B;

[0025] Step S4.6: Modify the INP file of the second state model B to assign UMAT material parameters, thereby achieving mesh mapping.

[0026] Furthermore, when a complete processing procedure is divided in step S1, it is divided into at least two different and consecutive processing steps; that is, the first processing step and the second processing step mentioned in step S2 and step S3 belong to the same complete processing procedure.

[0027] Furthermore, the specific operations of dividing the grid in step S2.3 are: selecting the appropriate grid unit type according to conditions such as material properties, deformation mode, calculation accuracy requirements and software function limitations; adjusting the grid unit density according to the concentrated area of ​​processing deformation, ensuring that each grid unit contains at least one identification point, each identification point represents a grain with a specific initial orientation, and numbering the grid units or identification points.

[0028] Furthermore, the specific operations of step S4.2 are: reading the grid information in the INP-A file through MATLAB; extracting the slip direction and slip plane normal based on the processed grain orientation in SDV-A; setting the slip direction as the X-axis, the slip plane normal as the Z-axis, and cross (X*Z) as the Y-axis to establish the first coordinate system A.

[0029] Furthermore, the specific operation of step S4.3 is: based on the inherent slip system of the material, define the theoretical slip direction and the normal direction of the slip surface, so as to construct the second coordinate system B.

[0030] Furthermore, the specific operation of step S4.4 is: extracting the orientation matrix A of the slip system A in the first coordinate system A and the orientation matrix B of the slip system B in the second coordinate system B; calculating the rotation matrix R:

[0031] R=Inv(A)*B

[0032] Where R is the rotation matrix from the first coordinate system A to the second coordinate system B; Inv is the inverse matrix identifier; A is the orientation matrix of the slip system A; B is the orientation matrix of the slip system B.

[0033] Furthermore, the weight of the orientation rotation is calculated by the accumulation of plastic strain or the activation degree of the slip system to modify the rotation matrix R to reflect the grain orientation after the actual deformation, thereby obtaining the rotation angle and direction of the grain relative to the initial state after the first processing step.

[0034] Furthermore, when the same grain corresponds to multiple grids, the average value of the rotation angles in the grids corresponding to the grain is taken as the R value of the grain.

[0035] Furthermore, step S4 needs to be executed once for each grid, thereby achieving grid mapping.

[0036] Beneficial effects: The crystal plasticity finite element mesh mapping method based on MATLAB of the present invention has the following advantages over the prior art:

[0037] 1. By dividing the complete processing process into multiple small deformation steps, severe mesh distortion during large deformation processes is effectively avoided, ensuring calculation stability and result accuracy.

[0038] 2. Through rotation matrix calculation and state variable mapping, the material deformation history (such as grain orientation) is accurately transferred between different process steps, ensuring physical continuity.

[0039] 3. It can be applied to various metal processing processes (such as rolling, stretching, forging, etc.), is not limited to specific materials or processes, and has good versatility.

[0040] 4. Improved computational efficiency: Compared with traditional single-step large deformation simulation, the step-by-step mapping method reduces the number of computational interruptions and restarts caused by mesh distortion, significantly improving computational efficiency.

[0041] 5. Support for complex working conditions: Able to handle complex crystal plastic behaviors such as material anisotropy and multi-slip system activation, meeting the needs of high-precision engineering analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 A flow chart of the crystal plasticity finite element mesh mapping method based on MATLAB provided by the present invention;

[0043] Figure 2 The rolled plate of the first state model A in the crystal plasticity finite element mesh mapping method based on MATLAB provided in the embodiment;

[0044] Figure 3 The roller of the first state model A in the crystal plasticity finite element mesh mapping method based on MATLAB provided in the embodiment;

[0045] Figure 4An assembly of the first state model A in the crystal plasticity finite element mesh mapping method based on MATLAB provided in an embodiment;

[0046] Figure 5 The crystal plasticity finite element mesh mapping method based on MATLAB provided in the embodiment is the rolled plate of the second state model B;

[0047] Figure 6 The roller of the second state model B in the crystal plasticity finite element mesh mapping method based on MATLAB provided in the embodiment;

[0048] Figure 7 An assembly of the second state model B in the crystal plasticity finite element mesh mapping method based on MATLAB provided in an embodiment;

[0049] Figure 8 The crystal plasticity constitutive model parameters in the ABAQUS input file (INP-B file) described in the MATLAB-based crystal plasticity finite element mesh mapping method provided in the embodiment;

[0050] Figure 9 (a) the initial grain orientation of the first state model A in the crystal plasticity finite element mesh mapping method based on MATLAB provided in the embodiment;

[0051] Figure 9 (b) the mesh deformation amplitude of the first state model A after processing in the crystal plasticity finite element mesh mapping method based on MATLAB provided in the embodiment;

[0052] Figure 10 (a) The grain orientation after plastic deformation of the first state model A in the crystal plasticity finite element mesh mapping method based on MATLAB provided in the embodiment;

[0053] Figure 10 (b) is the initial grain orientation of the second state model B in the crystal plasticity finite element mesh mapping method based on MATLAB provided in the embodiment. DETAILED DESCRIPTION

[0054] The present invention will be further described below with reference to the accompanying drawings.

[0055] like Figure 1 As shown, a crystal plasticity finite element mesh mapping method based on MATLAB includes the following steps:

[0056] Step S1: Divide the processing steps into several consecutive small deformation processing steps. Since the finite element mesh is prone to severe distortion during large deformation processes (such as rolling and stretching), which may lead to calculation interruption or distorted results, the complete processing step needs to be divided into several consecutive small deformation processing steps to maintain the mesh quality at each stage.

[0057] Step S2: Construct a crystal plastic constitutive model. Create a first-state model A in ABAQUS based on the first processing step, generate an ABAQUS output INP-A file, and output the state variable SDV-A of the model in the first processing step. It should be clarified here that the first-state model A is the material formed from the initial state after the first processing step, and is not the initial state of the material.

[0058] Step S3: Establish a second state model B according to the second processing step and generate an INP-B file;

[0059] Step S4: Use MATLAB to read the SDV-A data of the first state model A. Since the second state model B needs to inherit the deformation results of the first state model A to ensure physical continuity, it is necessary to convert the SDV-A data. Use the converted SDV-A data to construct the crystal plastic constitutive model of the second state model B, and implement material assignment by modifying the INP-B file, thereby realizing mesh remapping from the first state model A to the second state model B. It should be clarified here that mesh remapping refers to using the deformation results (such as grain orientation) of the material after the first state model A is formed by the first processing step as the initial condition of the second state model B, rather than direct model conversion.

[0060] Step S5: If there is a third processing step, proceed to steps 6 to 8;

[0061] Step S6: Use ABAQUS to output the INP-B file after the simulation of the second state model B, and output the state variable SDV-B of the second state model B in the second processing step;

[0062] Step S7: Create the third state model C according to the third processing step and generate the INP-C file

[0063] Step S8: Use MATLAB to read the SDV-B data of the second-state model B. Because the third-state model C needs to inherit the deformation results of the second-state model B to ensure physical continuity, it is necessary to convert the SDV-B data. Use the converted SDV-b data to construct the crystal plasticity constitutive model of the third-state model C, and implement material assignment by modifying the INP-C file, thereby achieving mesh remapping from the second-state model B to the third-state model C.

[0064] Step S9: If there is an Nth processing step, mesh remapping is performed on the Nth state model N in analogy to the operations of steps 6 to 8. The specific steps are:

[0065] a) Use ABAQUS to output the INP-(N-1) file after the (N-1)th state model (N-1) is simulated, and output the state variable SDV-(N-1) of the (N-1)th state model (N-1) in the (N-1)th process step;

[0066] b) Establish the Nth state model N according to the Nth processing step and generate the INP-N file;

[0067] c) Use MATLAB to read the SDV-(N-1) data of the (N-1)th state model (N-1). Since the Nth state model N needs to inherit the deformation results of the (N-1)th state model (N-1) to ensure physical continuity, it is necessary to convert the SDV-(N-1) data. Use the converted SDV-(N-1) data to construct the crystal plastic constitutive model of the Nth state model N, and realize material assignment by modifying the INP-N file, thereby realizing the mesh remapping of the (N-1)th state model (N-1) to the Nth state model N.

[0068] More specifically, when executing step S1 to divide a complete processing procedure, at least two different and continuous small deformation processing steps are divided; that is, the first processing step and the second processing step mentioned in step S2 and step S3 belong to the same complete processing procedure, that is, a complete processing procedure is divided into two continuous and different processing steps at the intermediate node in the processing step; simply, taking the stretching process of an aluminum bar as an example, the processing step of stretching the aluminum bar from the initial length to half of the target length is recorded as the first processing step, and the processing step of stretching the aluminum bar from half of the target length to the target length is recorded as the second processing step; therefore, the second processing step is further processed on the basis of the first processing step.

[0069] It should be emphasized that the stretching process of the aluminum bar proposed here is only to facilitate the understanding of the first processing step and the second processing step proposed in the present invention, and the finite element mesh mapping method described in the present invention can only be used for the stretching process; and the finite element mesh mapping method described in this scheme is mainly to continuously divide a complete processing process, rather than the number of divided processing steps; the more complex the processing process, the more continuous processing steps are divided, and correspondingly, the simpler the processing process, the fewer continuous processing steps are divided, and at least two.

[0070] More specifically, the following operations need to be performed when executing step S2 to construct the crystal plasticity constitutive model:

[0071] Step S2.1: Use the UMAT subroutine of ABAQUS to construct a crystal plasticity mechanics model that reflects the initial state of the material and accurately describes the constitutive relationship of the material when it is not affected by processing;

[0072] Step S2.2: Based on the small deformation in the first processing step, complete the geometric component design and assemble them to construct the model framework of the first state model A;

[0073] Step S2.3: Implement mesh discretization and set model parameters, such as contact properties, analysis condition settings, and load application, to complete the construction of the first state model A;

[0074] Step S2.4: Export the first state model A as an ABAQUS-specific INP-A file as the basis for subsequent simulation calculations;

[0075] Step S2.5: Perform simulation calculations on the material regarding the first state model A according to INP-A, extract and save various state variable data of the material at the end of the first processing stage, and form an SDV-A data file.

[0076] The specific operations of step S2.1 are as follows: create the material in ABAQUS, define the crystal plasticity constitutive relation through the UMAT subroutine, and set the crystal structure parameters, the number and direction of slip systems, and hardening parameters; at the same time, define the initial grain orientation of the material.

[0077] The specific operations of dividing the grid in step S2.3 are as follows: select the appropriate grid unit type according to conditions such as material properties, deformation mode, calculation accuracy requirements and software function limitations; adjust the grid unit density according to the concentrated area of ​​processing deformation, ensure that each grid unit contains at least one identification point, each identification point represents a grain with a specific initial orientation, and number the grid units or identification points; it should be emphasized here that no matter whether the selected crystal plasticity constitutive model is a single crystal or a polycrystalline, each identification point contains only one grain; and if a grid contains multiple identification points, it is necessary to ensure that the number of identification points in each grid is as equal as possible.

[0078] More specifically, when executing step S3 to establish the second state model B according to the second processing step, the following steps need to be performed:

[0079] Step S3.1: Based on the small deformation in the second processing step, complete the geometric component design and assemble them to build the model framework of the second state model B;

[0080] Step S3.2: Implement mesh discretization and set model parameters, such as contact properties, analysis condition settings, and load application, to complete the construction of the second state model B;

[0081] Step S3.3: Export the second state model B as an ABAQUS-specific INP-B file as the basis for subsequent simulation calculations.

[0082] Among them, the specific operation of dividing the grid in step S3.3 is the same as that in step 2.3, that is, selecting the appropriate grid unit type according to conditions such as material properties, deformation mode, calculation accuracy requirements and software function limitations; adjusting the grid unit density according to the concentrated area of ​​processing deformation, ensuring that each grid unit contains at least one identification point, each identification point represents a grain with a specific initial orientation, and numbering the grid units or identification points.

[0083] More specifically, the following operations are required when executing step S4 to implement mesh remapping from the first state model A to the second state model B:

[0084] Step S4.1: Reading the SDV-A data in the model A through the MATLAB program;

[0085] Step S4.2: Extract the first slip system A from the SDV-A file information. Based on the grain orientation of the material after the first processing step in the SDV-A, construct the first coordinate system A to describe the spatial orientation of the slip system A and quantify the slip behavior of the crystal.

[0086] Step S4.3: Setting the inherent slip system of the material as the second slip system B, and constructing a second coordinate system B about the second slip system B based on the inherent slip system of the material;

[0087] Step S4.4: Compare and analyze the spatial distribution characteristics of the grains in the first slip system A and the second slip system B, and then determine the rotation matrix R of the material grain orientation relative to the initial state after the first processing step, and obtain the grain orientation after the deformation in the first processing step;

[0088] Step S4.5: Based on the grain orientation obtained in step S4.4, construct the crystal plasticity constitutive model required for model B;

[0089] Step S4.6: Modify the INP file of model B to assign UMAT material parameters, thereby achieving mesh mapping.

[0090] The specific operations of step S4.2 are as follows: read the mesh information in the INP-A file through MATLAB; extract the slip direction and slip plane normal based on the processed grain orientation in SDV-A; set the slip direction as the X-axis, the slip plane normal as the Z-axis, and the cross (X * Z) as the Y-axis (i.e., cross (slip direction * slip plane normal)) to establish the first coordinate system A;

[0091] The specific operation of step S4.3 is: based on the inherent slip system of the material (such as {111}

[110] of aluminum), define the theoretical slip direction and the normal direction of the slip plane, thereby constructing the second coordinate system B.

[0092] The specific operations of step S4.4 are: extracting the orientation matrix A of the slip system A in the first coordinate system A and the orientation matrix B of the slip system B in the second coordinate system B; calculating the rotation matrix R:

[0093] R=Inv(A)*B

[0094] in,

[0095] R: is the rotation matrix from the first coordinate system A to the second coordinate system B;

[0096] Inv: Inverse matrix identifier;

[0097] A: is the orientation matrix of slip system A;

[0098] B: is the orientation matrix of slip system B;

[0099] The above formula can be used to obtain the rotation matrix R, and then the rotation matrix R is corrected by calculating the weight of the orientation rotation through the accumulation of plastic strain or the degree of slip system activation to reflect the grain orientation after the actual deformation, thereby obtaining the rotation angle and direction of the grain relative to the initial state after the first processing step; that is, the grain orientation information after the first processing step, which is used to construct the second state model B in the subsequent process; at the same time, it should be noted here that if the same grain corresponds to multiple grids (such as grains distributed across units), the average value of the rotation angles in each grid corresponding to the grain should be taken as the R value of the grain; and step S4 needs to be executed once for each grid until all are completed, thereby realizing grid mapping.

[0100] Taking the Accumulative Roll Bonding (ARB) process as an example, the specific scheme and effect of implementing grid mapping using the scheme of the present invention are introduced below. The scheme includes the following steps:

[0101] S1: Process division (corresponding to step S1)

[0102] The complete ARB rolling process is divided into two consecutive small deformation steps;

[0103] The first step: initial rolling of single-layer plate (corresponding to the first processing step)

[0104] The second step: cutting the rolled plate into several plate units of the same shape, and at least two, and stacking the several plate units on the rolling mill for secondary rolling (corresponding to the second processing step)

[0105] Avoid mesh distortion by dividing large deformation into multiple small deformation steps.

[0106] Construct the first state model A: Set the material parameter settings (corresponding to S2.1): Select aluminum alloy plate as the material of the first state model A, and set the aluminum alloy plate size to: 29×2mm 2 、Introduction area 2×1mm 2 , bite area 14mm, bite arc 199.5mm, rolling area 18×2mm 2 ;

[0107] like Figure 3 As shown, the roller is an analytical rigid body with a diameter of 155 mm;

[0108] Set the UMAT subroutine parameters:

[0109] Young's modulus: 70000MPa

[0110] Poisson's ratio: 0.35

[0111] Friction coefficient: 0.1 (corresponding to the "hardening parameter" in S2.1)

[0112] Mesh division: Select the C3D8R cell type to mesh the first state model A (corresponding to "Selecting the appropriate mesh cell type" in S2.3)

[0113] Mesh density: Enlarge the mesh in areas of concentrated deformation (such as bite areas) to ensure that each mesh cell contains at least one identification point;

[0114] Numbering rule: Sequentially number the grid units and identification points (corresponding to “numbering the grid units or identification points” in S2.3).

[0115] Output file: Generate the INP-A file of the first state model A (corresponding to S2.4).

[0116] Perform simulation calculations on the first state model A (for S2.5): Perform simulation calculations on the material on the first state model A according to INP-A, and extract the state variable SDV-A after the first step, including: the accumulated plastic strain around the grain orientation for subsequent rotation matrix correction.

[0117] S2: Establish the second state model B:

[0118] Geometric component design (corresponding to S3.1): Keep the same plate size as the first state model A (29×2mm 2 ), but the assembly relationship after the plates are stacked needs to be considered (corresponding to "Complete the geometric component design and assemble according to the small deformation in the second processing step" in S3.1).

[0119] Roller setting: The same analytical rigid roller as the first state model A (diameter 155mm, Figure 6 ).

[0120] Assembly and meshing (corresponding to S3.2): Mesh division strategy: consistent with the first state model A (corresponding to "mesh discretization processing" in S3.2).

[0121] Output file (corresponding to S3.3): Generate the INP-B file of the second state model B (as the basic file for subsequent mapping).

[0122] S3: Grid remapping implementation (corresponding to step S4 and sub-steps S4.1 to S4.6)

[0123] Data reading and coordinate system construction (corresponding to S4.1~S4.3)

[0124] Read SDV data (corresponding to S4.1):

[0125] The MATLAB script reads the mesh information in the INP-A file to determine the mesh number corresponding to the first-state model A. After determining the mesh number, the program uses the mesh number as an index to extract the parameters corresponding to each mesh from the SDV-A data output by the first-state model A. By calculating the change in SDV-A in the first-state model A before and after deformation, the orientation of the grains in the first-state model A after rolling is obtained.

[0126] Construct the first coordinate system A (corresponding to S4.2). The specific operation is: extract the slip direction after rolling (set as X axis) and the normal direction of the slip surface (set as Z axis) from SDV-A.

[0127] The Y axis is calculated by vector cross product: Y = X × Z (corresponding to "cross (slip direction * slip surface normal)" in S4.2).

[0128] Construct the second coordinate system B (corresponding to S4.3): Based on the inherent slip system of aluminum {111} <110> , define the theoretical slip direction and normal direction (corresponding to "constructing the second coordinate system B about the second slip B based on the inherent slip system of the material" in S4.3).

[0129] Rotation matrix calculation and orientation mapping (corresponding to S4.4~S4.6)

[0130] Calculate the rotation matrix R (corresponding to S4.4):

[0131] formula:

[0132] R=Inv(A)*B

[0133] in,

[0134] A: Orientation matrix of the slip system in the first coordinate system A

[0135] B: orientation matrix of the slip system in the second coordinate system B

[0136] Inv(A): inverse matrix of matrix A

[0137] Corrected rotation matrix (corresponding to S4.4):

[0138] Adjust R according to the accumulated plastic strain in SDV-A to obtain the grain orientation reflecting the true deformation (corresponding to "calculate the weight of orientation rotation by plastic strain accumulation or slip system activation degree and correct the rotation matrix R" in S4.4).

[0139] The specific programming part corresponding to the above process is as follows:

[0140] Definition, first state, the SDV data of model A after processing constitutes the matrix Sample system

[0141] The initial slip system corresponding to the material constitutes the matrix Crystal system

[0142] Cross represents a new vector that is perpendicular to the other two vectors

[0143] Here we take the aluminum alloy crystal plastic constitutive model as an example.

[0144] Sample_plane=[SDV37,SDV38,SDV39]

[0145] Sample_direction=[SDV73,SDV74,SDV75]

[0146] Sample_system=[Sample_direction,Cross(Sample_plane,Sample_direction,Sample_plane)]

[0147] Crystal_plane = [1 1 1];

[0148] Crystal_direction=[1 1 0];

[0149] Crystal_system=[Crystal_direction;Cross(Crystal_plane,Crystal_direction);Crystal_plane];

[0150] R (rotation angle) = inv (Sample_system) * Crystal_system

[0151] PROPS_57_59 = [1 0 0] * R;

[0152] PROPS_65_67=[0 1 0]*R;

[0153] At this time, PROPS_57_59 and PROPS_65_67 are the initial grain orientation information corresponding to the second state model B; it should be noted here that the above steps are executed for each grid in sequence until all are completed, thereby realizing grid mapping.

[0154] Modify the INP-B file (corresponding to S4.6):

[0155] Write the corrected grain orientation data into the UMAT material parameter part of the INP-B file of the second state model B (corresponding to "Modify the INP-B file of the second state model B to realize the assignment of UMAT material parameters" in S4.6).

[0156] Verification and result analysis:

[0157] Grain orientation comparison: Figure 9 (a) shows the initial random grain orientation of the first state model A, Figure 9 (b) is the mesh deformation amplitude after rolling (verifying the effectiveness of steps S1 to S2).

[0158] Experimental conclusion: Figure 10 (a) with Figure 10 (b) The comparison shows that the initial grain orientation of the second state model B is highly consistent with the final orientation of the first state model A (verifying the mapping accuracy of step S3).

[0159] By comparing the final grain orientation in the first state model A and the initial grain orientation in the second state model B, it is found that the technical solution provided by the present invention can not only achieve high-precision grid re-division, avoid grid distortion, and improve computing efficiency, but also can adapt to a variety of complex working conditions, which is sufficient to meet the needs of high-precision engineering analysis.

[0160] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A crystal plasticity finite element mesh mapping method based on MATLAB, characterized by: The following steps are involved: Step S1: Divide the processing steps into several consecutive small deformation processing steps; Step S2: Constructing a crystal plastic constitutive model, establishing a first state model A in ABAQUS according to the first processing step, generating an ABAQUS output INP-A file, and outputting the state variable SDV-A of the model in the first processing step; Step S3: Establish a second state model B according to the second processing step and generate an INP-B file; Step S4: Use MATLAB to read the SDV-A data of the first state model A and perform data conversion on the SDV-A. Use the converted SDV-A data to construct the crystal plasticity constitutive model of the second state model B, and implement material assignment by modifying the INP-B file, thereby achieving mesh remapping from the first state model A to the second state model B.

2. The crystal plasticity finite element mesh mapping method based on MATLAB according to claim 1, characterized in that: Step S2 includes the following steps: Step S2.1: Use the UMAT subroutine of ABAQUS to construct a crystal plasticity mechanics model that reflects the initial state of the material; Step S2.2: Constructing a model framework of the first state model A based on the small deformation of the first processing step; Step S2.3: Implement grid discretization processing, set model parameters, and complete the construction of the first state model A; Step S2.4: Export the first state model A as an ABAQUS-specific INP-A file; Step S2.5: Perform material simulation calculations on the first state model A according to INP-A and generate an SDV-A data file.

3. The crystal plasticity finite element mesh mapping method based on MATLAB according to claim 1, characterized in that: Step S3 includes the following steps: Step S3.1: Constructing a model framework of the second state model B based on the small deformation of the second processing step; Step S3.2: Implement grid discretization processing, set model parameters, and complete the construction of the second state model B; Step S3.3: Export the second state model B as an ABAQUS-specific INP-B file.

4. The crystal plasticity finite element mesh mapping method based on MATLAB according to claim 1, characterized in that: Step S4 includes the following steps: Step S4.1: Reading the SDV-A data of the first state model A through the MATLAB program; Step S4.2: Extract the first slip system A based on the SDV-A file information. Based on the grain orientation of the material after the first processing step in the SDV-A, construct the first coordinate system A to describe the spatial orientation of the slip system A. Step S4.3: Setting the inherent slip system of the material as the second slip system B, and constructing a second coordinate system B about the second slip system B based on the inherent slip system of the material; Step S4.4: Compare and analyze the spatial distribution characteristics of the grains in the first slip system A and the second slip system B, and then determine the rotation matrix R of the material grain orientation relative to the initial state after the first processing step, and obtain the grain orientation after the deformation in the first processing step; Step S4.5: Based on the grain orientation obtained in step S4.4, construct the crystal plastic constitutive model required for the second state model B; Step S4.6: Modify the INP file of the second state model B to assign UMAT material parameters, thereby achieving mesh mapping.

5. The crystal plasticity finite element mesh mapping method based on MATLAB according to claim 1, characterized in that: When a complete processing procedure is divided in step S1, it is divided into at least two different and consecutive processing steps; that is, the first processing step and the second processing step mentioned in step S2 and step S3 belong to the same complete processing procedure.

6. The crystal plasticity finite element mesh mapping method based on MATLAB according to claim 2, characterized in that: The specific operations of meshing in step S2.3 are as follows: select the appropriate mesh unit type based on conditions such as material properties, deformation mode, calculation accuracy requirements and software function limitations; adjust the mesh unit density according to the concentrated area of ​​processing deformation, ensure that each mesh unit contains at least one identification point, each identification point represents a grain with a specific initial orientation, and number the mesh units or identification points.

7. The crystal plasticity finite element mesh mapping method based on MATLAB according to claim 4, characterized in that: The specific operations of step S4.2 are: read the grid information in the INP-A file through MATLAB; extract the slip direction and slip plane normal based on the processed grain orientation in SDV-A; set the slip direction as the X-axis, the slip plane normal as the Z-axis, and cross (X*Z) as the Y-axis to establish the first coordinate system A.

8. The crystal plasticity finite element mesh mapping method based on MATLAB according to claim 4, characterized in that: The specific operation of step S4.3 is: based on the inherent slip system of the material, define the theoretical slip direction and the normal direction of the slip surface, and thus construct the second coordinate system B.

9. The crystal plasticity finite element mesh mapping method based on MATLAB according to claim 4, characterized in that: The specific operations of step S4.4 are: extracting the orientation matrix A of the slip system A in the first coordinate system A and the orientation matrix B of the slip system B in the second coordinate system B; calculating the rotation matrix R: R=Inv(A)*B Where R is the rotation matrix from the first coordinate system A to the second coordinate system B; Inv is the inverse matrix identifier; A is the orientation matrix of the slip system A; B is the orientation matrix of the slip system B.

10. The crystal plasticity finite element mesh mapping method based on MATLAB according to claim 9, characterized in that: The weighted correction rotation matrix R of the orientation rotation is calculated by calculating the plastic strain accumulation or the activation degree of the slip system to reflect the grain orientation after the actual deformation, thereby obtaining the rotation angle and direction of the grain relative to the initial state after the first processing step.

11. The crystal plasticity finite element mesh mapping method based on MATLAB according to claim 9, characterized in that: When the same grain corresponds to multiple grids, the average value of the rotation angles in the grids corresponding to the grain is taken as the R value of the grain.

12. The crystal plasticity finite element mesh mapping method based on MATLAB according to claim 1, characterized in that: The step S4 needs to be executed once for each grid, thereby achieving grid mapping.

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