A discrete dislocation dynamics modeling method considering twin stress field

Abstract

The present invention relates to a discrete dislocation dynamics modeling method considering the twin stress field, comprising: obtaining the twin characteristic parameters of the target crystal material through a plastic deformation test, constructing a discrete dislocation dynamics geometric model containing a twin domain, and applying the loading conditions of the plastic deformation test as boundary conditions to the geometric model; wherein the applied boundary conditions are decomposed into an elastic field generated by dislocations in an infinite continuous medium, an additional field for correcting the true boundary conditions, and a superposition of the twin elastic field in the infinite continuous medium through a superposition algorithm framework, thereby obtaining the displacement, stress, and strain generated during plastic deformation inside the target crystal material. Based on this, the Peach-Koehler force exerted on the dislocation is calculated, and the evolution of the dislocation in the target crystal material is iteratively corrected according to the calculated Peach-Koehler force combined with other dislocation-related mechanisms. In this way, the influence of the twin-dislocation interaction during the plastic deformation of the material can be accurately revealed.

Description

Technical Field

[0001] The present invention relates to the field of material science, and in particular to a discrete dislocation dynamics modeling method considering twin stress fields. Background Art

[0002] In the field of materials science, accurately predicting the plastic deformation behavior of crystalline materials is of great value for understanding material failure mechanisms and optimizing material properties. The plastic deformation of metallic materials primarily relies on the slip mechanism, but in hexagonal close-packed (HCP) materials such as magnesium alloys, α-zirconium, and α-titanium, the synergistic effect of twinning deformation is also required. Discrete dislocation plasticity (DDP) theory is an effective tool for analyzing dislocation-scale plastic behavior. Traditional modeling methods typically simplify twins into static grain boundaries or lattice reorientation regions, ignoring the associated strain fields generated during twin nucleation, resulting in an incomplete description of twin-dislocation interactions.

[0003] Some existing studies have simulated twin stress fields using crystal plasticity finite element models. However, these methods suffer from high computational costs, complex mesh reconstruction, and difficulty directly analyzing the interaction between dislocations and twins. Other methods based on discrete dislocation dynamics approximate twin boundaries using arrays of twin dislocations. However, these methods require additional definition of dislocation motion rules, resulting in high model complexity and inability to account for the effects of matrix dislocations.

[0004] Therefore, there is an urgent need for a modeling method that can accurately characterize the twin-dislocation interaction and take into account both computational efficiency and accuracy. Summary of the Invention

[0005] The purpose of this section is to summarize some aspects of the embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract and title of this application to avoid obscuring the purpose of this section, the abstract and the title of the invention, and such simplifications or omissions should not be used to limit the scope of the present invention.

[0006] In view of the above problems and / or the problems existing in the prior art, the present invention is proposed.

[0007] In order to solve the technical problem of the lack of autonomous generation of twin stress fields that conform to crystallographic characteristics within the framework of discrete dislocation dynamics, the present invention provides a discrete dislocation dynamics modeling method considering twin stress fields, comprising:

[0008] Performing a plastic deformation test on the target crystal material to obtain twin characteristic parameters of the target crystal material under the plastic deformation test;

[0009] Based on the crystallographic information and twin characteristic parameters of the target crystal material, a discrete dislocation dynamics geometric model including twin domains is constructed;

[0010] The loading conditions of the plastic deformation test are applied to the geometric model as boundary conditions. Based on the dislocation evolution mechanism, the dynamic evolution of dislocations in the target crystal material during plastic deformation is simulated. The applied boundary conditions are decomposed into the superposition of the elastic field generated by dislocations in the infinite continuum, the additional field used to correct the true boundary conditions, and the elastic field of twins in the infinite continuum through a superposition algorithm framework. The displacement, stress, and strain generated by plastic deformation inside the target crystal material are obtained.

[0011] Calculate the Peach-Koehler force on dislocations based on the stress generated during plastic deformation of the target crystal material;

[0012] Based on the calculated Peach-Koehler forces and combined with other dislocation-related mechanisms, the evolution of dislocations in the target crystal material is iteratively corrected.

[0013] In some possible implementations, the superposition algorithm framework is expressed as:

[0014] ;

[0015] ;

[0016] ;

[0017] in, represents the actual displacement, represents the actual strain, represents the actual stress; represents the displacement field of the dislocation, represents the additional field of displacement, represents the displacement field of the twin; represents the strain field of the dislocation, represents the additional field of strain, represents the strain field of the twin; represents the stress field of the dislocation, represents the additional field of stress, Represents the stress field of the twin.

[0018] In some possible implementations, the additional field is solved using a numerical analysis method, including but not limited to a finite element method, a boundary element method, or a discrete element method;

[0019] The elastic field is calculated using elasticity theory, specifically the superposition of all dislocation elastic fields;

[0020] in, Expressed as:

[0021] ;

[0022] in, Indicates the dislocations, N represents the number of dislocations, Indicates the The elastic field strain of a dislocation;

[0023] Expressed as:

[0024] ;

[0025] in, Indicates the The elastic field stress of a dislocation.

[0026] In some possible implementations, the twin stress field calculation method includes:

[0027] The twin morphology is simplified to an elliptical shape, a Cartesian coordinate system is established, and the characteristic strain tensor is defined as:

[0028] ;

[0029] in, represents the intrinsic strain expressed by the strain field tensor in a rectangular coordinate system with the twin center as the origin, represents the magnitude of the twin shear strain component, Represents the transpose of a matrix;

[0030] According to the characteristic strain tensor, the strain field, stress field and displacement field of the twin are calculated respectively based on elastic mechanics.

[0031] In some possible implementations, the Peach-Koehler force is calculated as:

[0032] ;

[0033] in, Indicates the The Peach-Koehler force of a dislocation, Indicates the The normal to the slip plane of a dislocation, Indicates the The Burgers vector of a dislocation; Indicates the The stress field of a dislocation, Indicates the The stress field of a twin.

[0034] One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages:

[0035] The present invention provides a discrete dislocation dynamics modeling method considering the twin stress field, which obtains the twin characteristic parameters of the target crystal material under the plastic deformation test by performing a plastic deformation test on the target crystal material; constructs a discrete dislocation dynamics geometric model containing a preset twin domain based on the crystallographic information and twin characteristic parameters of the target crystal material; applies the loading conditions of the plastic deformation test as boundary conditions to the geometric model, and simulates the dynamic evolution process of dislocations of the target crystal material during the plastic deformation process based on the dislocation evolution mechanism; wherein, the applied boundary conditions are decomposed into an elastic field generated by dislocations in an infinite continuous medium, an additional field for correcting the real boundary conditions, and a superposition of the twin elastic field in the infinite continuous medium through a superposition algorithm framework, so as to obtain the displacement, stress and strain generated during the actual plastic deformation of the target crystal material; based on the displacement, stress and strain generated during the actual plastic deformation of the target crystal material, the Peach-Koehler force exerted on the dislocation is calculated, and the evolution of dislocations in the target crystal material is iteratively corrected using the calculated Peach-Koehler force in combination with other dislocation-related mechanisms. In this way, by introducing the twin stress field, a discrete dislocation dynamics geometric model including the twin domain is constructed. Through this model, the twin boundary effect, twin morphology evolution and the related local stress state can be systematically considered, thereby accurately revealing the influence of twin-dislocation interaction during the plastic deformation process of the material. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments of the present invention. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0037] Figure 1 A schematic flow chart of an embodiment of a discrete dislocation dynamics modeling method considering twin stress fields provided by an embodiment of the present invention;

[0038] Figure 2 A schematic diagram of superimposing discrete dislocation dynamics in the prior art;

[0039] Figure 3 A schematic diagram of superimposing discrete dislocation dynamics in an embodiment of the present invention;

[0040] Figure 4 This is a flowchart of discrete dislocation dynamics modeling considering twin stress field in an embodiment of the present invention. DETAILED DESCRIPTION

[0041] The following will be combined with the accompanying drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0042] In the relevant description of this embodiment, the terms "including, containing, having" and the like are open terms and are generally understood to include but not be limited to; the term "at least one" is generally understood to mean one or more, where "plurality" refers to two or more; the term "at least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items, for example, "at least one of a, b or c", or "at least one of a, b and c", can all represent: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, c can be single or multiple respectively; the symbol "A / B" is used to describe the selection relationship of associated objects, generally indicating an "or" relationship before and after.

[0043] In the following description of the present embodiment, the terms used in the embodiments of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. The singular forms "a", "an" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise.

[0044] Those skilled in the art should understand that in the following description of the embodiments of the present application, the order of serial numbers does not mean the order of execution, some or all of the steps can be executed in parallel or sequentially, and the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0045] It will be understood by those skilled in the art that the numerical ranges in the examples of the present application are to be understood as also specifically disclosing each intermediate value between the upper and lower limits of the ranges. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the range is also included in the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded in the scope.

[0046] Unless otherwise indicated, the technical / scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which this application belongs. Although this application describes only preferred methods and materials, any methods and materials similar or equivalent to those herein may also be used in the implementation or testing of this application. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In the event of any conflict with any incorporated document, the content of this specification shall prevail.

[0047] In order to illustrate the technical solution of the present invention, specific embodiments are provided below.

[0048] In the field of materials science, accurately predicting the plastic deformation behavior of crystalline materials is of great value for understanding material failure mechanisms and optimizing material properties. The plastic deformation of metallic materials mainly relies on the slip mechanism, but in close-packed hexagonal materials such as magnesium alloys, α-zirconium, and α-titanium, the synergistic effect of twin deformation is also required. Discrete dislocation plasticity theory is an effective tool for analyzing dislocation-scale plastic behavior. Traditional modeling methods usually simplify twins into static grain boundaries or lattice reorientation regions, ignoring the related strain fields generated during the twin nucleation process, resulting in an incomplete description of twin-dislocation interactions.

[0049] Some existing studies have simulated twin stress fields using crystal plasticity finite element models. However, these methods suffer from high computational costs, complex mesh reconstruction, and difficulty directly analyzing the interaction between dislocations and twins. Other methods based on discrete dislocation dynamics approximate twin boundaries using arrays of twin dislocations. However, these methods require additional definition of dislocation motion rules, resulting in high model complexity and inability to account for the effects of matrix dislocations.

[0050] Therefore, there is an urgent need for a modeling method that can accurately characterize the twin-dislocation interaction and take into account both computational efficiency and accuracy.

[0051] Figure 1 A schematic diagram of an embodiment of a discrete dislocation dynamics modeling method considering twin stress field provided by an embodiment of the present invention is shown in FIG. Figure 1 As shown, the above method may include:

[0052] S101, performing a plastic deformation test on a target crystal material to obtain twin characteristic parameters of the target crystal material under the plastic deformation test;

[0053] The target crystal material is the crystalline material being studied and can be any material capable of plastic deformation, such as metals (e.g., magnesium alloys and zirconium alloys) or semiconductors. Dislocation motion occurs when dislocation lines in a crystal move along slip planes under shear stress, leading to relative slip and plastic deformation. Twinning, on the other hand, occurs when a portion of a crystal undergoes uniform shear along specific crystal planes and directions, creating a mirror-symmetrical orientation between this portion and the base crystal, thereby producing a twin structure. Plastic deformation testing of the target crystal material reveals twinning parameters, including the formation mechanism, morphology, and distribution of twins, under varying plastic deformation loading conditions (e.g., deformation temperature, deformation rate, and degree of deformation).

[0054] S102, constructing a discrete dislocation dynamics geometric model including twin domains based on crystallographic information and twin characteristic parameters of the target crystal material;

[0055] Crystallographic information about the target crystal material includes its lattice type (such as the hexagonal close-packed (HCP) structure mentioned above), lattice parameters, crystal plane and orientation indices, and slip system. This information determines the crystallographic basis for the material's plastic deformation. Twinning characteristic parameters, including twin planes, shear direction, shear amount, and twin orientation relationships, define the geometric and mechanical properties of twinning deformation.

[0056] Discrete Dislocation Dynamics (DDD), a branch of dislocation dynamics, uses a discretization approach to simulate the behavior of dislocations in crystals. Dislocations are a key defect in crystals, arising from the disordered arrangement of atoms and significantly affecting the physical and mechanical properties of the material. Based on the crystallographic information and twinning characteristic parameters of the target crystal material, computer simulation software can be used to construct a geometric model containing twin domains.

[0057] S103, applying the loading conditions of the plastic deformation test as boundary conditions to the geometric model, and simulating the dynamic evolution of dislocations of the target crystal material during the plastic deformation process based on the dislocation evolution mechanism;

[0058] The imposed boundary conditions are decomposed into the elastic field generated by dislocations in the infinite continuum, the additional field used to correct the true boundary conditions, and the superposition of the elastic field of twins in the infinite continuum through a superposition algorithm framework. The displacement, stress, and strain generated during plastic deformation of the target crystal material are obtained.

[0059] The dynamic evolution of dislocations is used to describe the dynamic distribution and morphological changes of dislocations in the target crystal material. Dislocation evolution mechanisms include, but are not limited to, dislocation multiplication, dislocation movement, interaction, and annihilation. Different target crystal materials have corresponding dislocation evolution mechanisms.

[0060] In some embodiments, the superposition algorithm framework can be expressed by the following formula:

[0061] ;

[0062] ;

[0063] ;

[0064] in, represents the actual displacement, represents the actual strain, represents the actual stress; represents the displacement field of the dislocation, represents the additional field of displacement, represents the displacement field of the twin; represents the strain field of the dislocation, represents the additional field of strain, represents the strain field of the twin; represents the stress field of the dislocation, represents the additional field of stress, Represents the stress field of the twin.

[0065] It should be noted that the core of the superposition method is to decompose complex mechanical problems into simple sub-problems that can be solved independently. The traditional superposition method only considers the superposition of the dislocation's own elastic field and the boundary additional field, such as Figure 2 As shown, the boundary values ​​of the twinning domain involve displacement boundary conditions ( ) and traction boundary conditions ( ). The displacement boundary conditions include the displacement field of the dislocation and additional fields of displacement The traction boundary condition includes the force of the dislocation on the sample surface. and the force of the correction field on the sample surface However, the local deformation caused by the twin domain will change the overall stress distribution, so the twin stress field needs to be introduced as an independent component. Figure 3 As shown, in the embodiment of the present invention, a new superposition method is used to introduce the twin stress field as a new boundary condition. At this time, the displacement boundary condition includes the displacement field of the dislocation , additional field of displacement and the displacement field of the twin The traction boundary condition includes the force of the dislocation on the sample surface. , the force of the correction field on the sample surface and the force of the twins on the sample surface In this way, the influence of the twin stress field can be considered in the simulation of the plastic deformation process inside the material.

[0066] The mathematical expression of the superposition method is a linear combination of three independent fields. The displacement field of dislocations describes the displacement response of discrete dislocations under ideal conditions, the displacement field of twins characterizes the intrinsic deformation effects of local regions of the material, and the additional displacement field corrects for the influence of actual geometric constraints on the global solution. The composition of the total displacement field reflects the synergistic effect of all deformation mechanisms within the material. The lattice distortion caused by dislocations, shear deformation of twins, and boundary constraint effects form a macroscopically observable displacement distribution through vector superposition. The superposition of strain fields must satisfy the linear superposition principle under deformation conditions, and the strain tensors of each component field are algebraically added at the material point.

[0067] In some embodiments, the additional fields are solved using numerical analysis methods, including but not limited to the finite element method, the boundary element method, or the discrete element method;

[0068] The elastic field is calculated using elasticity theory, specifically the superposition of all dislocation elastic fields;

[0069] in, Expressed as:

[0070] ;

[0071] in, Indicates the dislocations, N represents the number of dislocations, Indicates the The elastic field strain of a dislocation;

[0072] Expressed as:

[0073] ;

[0074] in, Indicates the The elastic field stress of a dislocation.

[0075] In some embodiments, The elastic field stress of a dislocation is expressed as:

[0076] ;

[0077] in:

[0078] ;

[0079] ;

[0080] ;

[0081] in, is the shear modulus, is the Burgers vector, is Poisson's ratio, , is the coordinate of the current dislocation in the local coordinate system;

[0082] No. The elastic field strain of a dislocation is expressed as:

[0083] ;

[0084] in:

[0085] ;

[0086] ;

[0087] .

[0088] In some embodiments, a method for calculating the twin stress field includes:

[0089] The twin morphology is simplified to an elliptical shape, a Cartesian coordinate system is established, and the characteristic strain tensor is defined as:

[0090] ;

[0091] in, represents the intrinsic strain expressed by the strain field tensor in a rectangular coordinate system with the twin center as the origin, represents the magnitude of the twin shear strain component, Represents the transpose of a matrix.

[0092] According to the characteristic strain tensor, the strain field, stress field and displacement field of the twin are calculated respectively based on elastic mechanics.

[0093] Exemplarily, calculating the strain field, stress field, and displacement field of the twins based on elastic mechanics may include: deriving explicit analytical forms of the Eshelby tensors G, H, and W using a virtual ellipse technique, and calculating the strain field, stress field, and displacement field of the twins using the following formulas:

[0094] ;

[0095] ;

[0096] .

[0097] In Eshelby inclusion theory, G, H and W tensors represent the transformation tensors of strain field, stress field and displacement field respectively. They are the core tools of Eshelby theory and are used to transform the intrinsic strain of twins into By separating these three tensors, the superposition method can be used to explicitly couple the twin and dislocation fields, overcoming the limitation of traditional models that cannot simultaneously handle dislocation motion and twin shear deformation.

[0098] Specifically, in some embodiments, the calculation of the Eshelby tensor includes:

[0099] Assuming that there is a confocal ellipse outside the elliptical twin, the formula is expressed as:

[0100] ;

[0101] in, Represents the largest positive root;

[0102] The largest positive root is expressed as:

[0103]

[0104] Under this condition the external normal vector and The functions are:

[0105] ;

[0106] ;

[0107] ;

[0108] ;

[0109] in, , ;

[0110] based on The function matrix solves the components of the strain field tensor G, stress field tensor H and displacement field tensor W, where Functions include:

[0111] ;

[0112] ;

[0113] ;

[0114] .

[0115] Furthermore, in order to express tensors in matrix form, the Voigt representation method can be used in the embodiment of the present invention. Therefore, the strain field formula of the above twin can be further expressed as:

[0116] ;

[0117] in:

[0118] ;

[0119] ;

[0120] ;

[0121] ;

[0122] ;

[0123] ;

[0124] ;

[0125] ;

[0126] ;

[0127] ;

[0128]

[0129]

[0130]

[0131]

[0132]

[0133] in, represents Poisson's ratio.

[0134] Similarly, the stress field formula of twins is Expressed as:

[0135]

[0136] in:

[0137] ;

[0138] ;

[0139] ;

[0140] ;

[0141] ;

[0142] ;

[0143] ;

[0144] On the displacement field of twins The calculation formula can be expressed as:

[0145] ;

[0146] in:

[0147] ;

[0148] ;

[0149] ;

[0150] ;

[0151] ;

[0152] ;

[0153] ;

[0154] ;

[0155] ;

[0156] ;

[0157] By setting and The interior point Eshelby tensor of the twin domain can be derived.

[0158] S104, calculating the Peach-Koehler force on the dislocation based on the stress generated during plastic deformation inside the target crystal material;

[0159] S105, iteratively correcting the evolution of dislocations in the target crystal material based on the calculated Peach-Koehler force and in combination with other dislocation-related mechanisms.

[0160] It should be noted that, through the aforementioned superposition method, the present invention enables simultaneous calculation of the evolution of discrete twins, the dislocation structure within the grains, and their stress-strain distribution under applied load conditions. Specifically, the boundary field is calculated based on the twin size, position, and dislocation distribution at the current increment, and then a modified finite element problem is solved for the applied load increment. Applying the same loading conditions to the discrete dislocation dynamics geometry model as in the plastic deformation test eliminates the influence of external factors on the accuracy of the plastic deformation simulation.

[0161] The evolution of the dislocation structure is determined by the Peach-Koehler force on each dislocation and the application of the rules for dislocation nucleation, motion, and annihilation. After obtaining the updated dislocation structure, it is combined with the twin structure in the next increment and the above calculation process is repeated. It should be noted that the dislocation is driven by the complete mechanical field, not just the field calculated in the dislocation subproblem. Both the finite element and twin subproblems affect the dislocation structure and its evolution. Therefore, in this superposition framework, the Peach-Koehler force on the first dislocation is The calculation is as follows:

[0162] ;

[0163] in, Indicates the The Peach-Koehler force of a dislocation, Indicates the The normal to the slip plane of a dislocation, Indicates the The Burgers vector of a dislocation; Indicates the The stress field of a dislocation, Indicates the The stress field of a twin.

[0164] When the Peach-Koehler force is sufficiently large, it activates dislocation sources (such as Frank-Read sources), generating new dislocation loops and expanding them, leading to an increase in dislocation density. Simultaneously, during their motion, dislocations may encounter other dislocations or crystal defects (such as twin boundaries), interacting with them through various processes, including but not limited to reflection, absorption, or annihilation, thereby changing the morphology and distribution of dislocation lines. Furthermore, twin boundaries have a unique influence on dislocation motion, reflecting dislocations and changing their direction of motion, while also absorbing them and promoting twin thickening. These processes together constitute a complex landscape of dislocation evolution, which determines the plastic deformation behavior and mechanical properties of the material.

[0165] The following combination Figure 4 The above steps S101 to S105 are described in detail.

[0166] Figure 4This is a flowchart of discrete dislocation dynamics modeling considering twin stress field in an embodiment of the present invention, see Figure 4 As shown in the figure, first, the material constants of the target crystal material and the computational information required for the simulation are input to construct a discrete dislocation dynamics geometric model. In the constructed combined model, a slip plane is defined and dislocation sources and obstacles are randomly distributed on the slip plane. Then, a matrix is ​​initialized to store dislocation motion trajectories, stress-strain data, and dislocation nucleation and escape time data, where Figure 4 middle is the current time, is the total time that the plastic boundary conditions are applied (i.e., the preset dislocation dynamics solution time step).

[0167] First of all, Initialize, Figure 4 In Chinese it is represented as: ;judge When , the plastic deformation time step cycle is entered. Within the time step cycle, the pinning and release of dislocations at obstacles are simulated with constant time increments. For example, represents a constant time increment in the time step cycle, expressed as:

[0168] ;

[0169] Within each time-stepping loop, the boundary conditions described in step S103 are applied to the target crystal material to detect dislocation nucleation in real time. Upon detecting dislocation nucleation, the dislocation evolution process in the target crystal material is corrected in real time through the process described in step S105. The Peach-Koehler scatterplot calculated in step S104 is primarily used to correct the dislocation velocity during the dislocation evolution process in the target crystal material.

[0170] In an embodiment of the present invention, a plastic deformation test is performed on a target crystal material to obtain the twin characteristic parameters of the target crystal material under the plastic deformation test; a discrete dislocation dynamics geometric model including a preset twin domain is constructed based on the crystallographic information and twin characteristic parameters of the target crystal material; the loading conditions of the plastic deformation test are applied to the geometric model as boundary conditions, and based on the dislocation evolution mechanism, the dynamic evolution process of dislocations in the target crystal material during plastic deformation is simulated; wherein, the applied boundary conditions are decomposed into an elastic field generated by dislocations in an infinite continuous medium, an additional field for correcting the real boundary conditions, and a superposition of the twin elastic field in the infinite continuous medium through a superposition algorithm framework, so as to obtain the displacement, stress, and strain generated in the target crystal material during plastic deformation; based on the displacement, stress, and strain generated during the actual plastic deformation of the target crystal material, the Peach-Koehler force exerted on the dislocation is calculated, and the calculated Peach-Koehler force is combined with other dislocation-related mechanisms to iteratively correct the evolution of dislocations in the target crystal material. In this way, the nonlocal mechanical effects of twins and the discrete motion laws of dislocations are unified into a single mechanical framework through the superposition method, resolving the problem that traditional discrete dislocation dynamics models fail to consider the interaction between twins and dislocations. Furthermore, coupling the twin stress field during the boundary condition determination step avoids the redundant recalculation of the twin field during the dislocation dynamic evolution step. The dislocation motion equation relies solely on the total stress field after superposition, without the need to explicitly introduce complex coupling terms. Together, these provide a physically self-consistent and efficient framework for revealing the twin-dislocation cooperative deformation mechanism, and a rigorous mathematical and physical foundation for revealing the twin-dislocation cooperative deformation mechanism.

[0171] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other. Each embodiment focuses on the differences from other embodiments.

[0172] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit the present application. Although the present application has been described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned embodiments can still be modified, or some or all of the technical features therein can be replaced by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present application.

Claims

1. A discrete dislocation dynamics modeling method considering twin stress field, characterized in that: include: performing a plastic deformation test on a target crystal material to obtain twin characteristic parameters of the target crystal material under the plastic deformation test; Constructing a discrete dislocation dynamics geometric model containing a preset twin domain based on the crystallographic information of the target crystal material and the twin characteristic parameters; wherein the crystallographic information includes the lattice type, lattice parameters, crystal plane index and crystal direction index, and slip system of the target crystal material; and the twin characteristic parameters include twin planes, shear direction, shear amount, and twin orientation relationship; The loading conditions of the plastic deformation test are applied to the geometric model as boundary conditions. Based on the dislocation evolution mechanism, the dynamic evolution process of dislocations in the target crystal material during plastic deformation is simulated. The applied boundary conditions are decomposed into the superposition of the elastic field generated by dislocations in an infinite continuous medium, the additional field used to correct the true boundary conditions, and the elastic field of twins in the infinite continuous medium through a superposition algorithm framework, thereby obtaining the displacement, stress, and strain generated in the target crystal material during plastic deformation. The superposition algorithm framework is expressed as: ； ； ； in, represents the actual displacement, represents the actual strain, represents the actual stress; represents the displacement field of the dislocation, represents the additional field of displacement, represents the displacement field of the twin; represents the strain field of the dislocation, represents the additional field of strain, represents the strain field of the twin; represents the stress field of the dislocation, represents the additional field of stress, represents the stress field of the twin; Calculating the Peach-Koehler force on the dislocation based on the stress generated during plastic deformation of the target crystal material; The evolution of dislocations in the target crystal material is iteratively corrected based on the calculated Peach-Koehler forces and in combination with dislocation-related mechanisms, wherein the dislocation-related mechanisms include dislocation nucleation, motion, and annihilation rules.

2. The method according to claim 1, characterized in that The additional fields are solved using numerical analysis methods, including the finite element method, boundary element method, or discrete element method; The elastic field is calculated using elastic mechanics theory, and all dislocation elastic fields are superimposed; in, Expressed as: ； in, Indicates the dislocations, N represents the number of dislocations, Indicates the The elastic field strain of a dislocation; Expressed as: ； in, Indicates the The elastic field stress of a dislocation.

3. The method according to claim 2, characterized in that The calculation methods of twin stress field include: The twin morphology is simplified to an elliptical shape, a Cartesian coordinate system is established, and the characteristic strain tensor is defined as: ； in, represents the intrinsic strain expressed by the strain field tensor in a rectangular coordinate system with the twin center as the origin, represents the magnitude of the twin shear strain component, Represents the transpose of a matrix; According to the characteristic strain tensor, the strain field, stress field and displacement field of the twin are calculated based on elastic mechanics.

4. The method according to claim 3, characterized in that The calculation formula of the Peach-Koehler force is expressed as: ； in, Indicates the The Peach-Koehler force of a dislocation, Indicates the The normal to the slip plane of a dislocation, Indicates the The Burgers vector of a dislocation; Indicates the The stress field of a dislocation, Indicates the The stress field of a twin.

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