Diamond indenter model construction method, device, equipment and medium
By constructing a diamond indenter model with a custom crystal orientation and dividing it into multiple temperature-controlled regions, the problem of abnormal deformation of the cubic diamond indenter model under extreme conditions was solved, and accurate simulation under extreme conditions was achieved.
Patent Information
- Application Number
- CN202511297849.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-11
- Publication Date
- 2025-12-19
AI Technical Summary
Traditional cubic diamond indenter models suffer from anisotropy under extreme loads or high strain rates, leading to errors in simulation results and failing to effectively reflect the properties of the material.
By setting the basic macroscopic parameters of the diamond indenter model, it is divided into multiple temperature control regions. The temperature control regions are determined based on the equivalent cone angle, vertex coordinates, and the height of different temperature control regions. The unit cell and initial basis vectors are determined, and the model is rotated to the target crystal orientation with the strongest resistance to deformation. Carbon atoms are then filled to construct the target diamond indenter model.
This approach reduces the impact of indenter deformation on simulation results under extreme conditions, ensuring that the simulation results reflect the mechanical response of the sample itself, avoiding indenter failure behavior, and improving the accuracy and reliability of the simulation.
Smart Images
Figure CN121171379A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of molecular dynamics simulation and calculation technology, specifically to a method, apparatus, molecular dynamics simulation equipment, and medium for constructing a diamond indenter model. Background Technology
[0002] In molecular dynamics (MD) simulations of nanoindentation, diamond indenters are widely used to study the mechanical behavior of materials due to their ultra-high hardness and chemical stability. However, the cubic diamond (CD) indenter model used in traditional simulations has significant problems under extreme loads or high strain rates: anisotropy limitation: the mechanical properties of cubic diamond are significantly anisotropic, and the elastic modulus and yield strength of different crystal orientations (such as
[100] and
[111] ) are quite different. If the orientation of the indenter model is not properly selected, it may exacerbate the simulation error.
[0003] Current methods include: 1. Improving the accuracy of the potential function, but not completely avoiding structural instability; 2. Limiting the simulated load or strain rate, but sacrificing the ability to study under extreme conditions; 3. Using the rigid indenter assumption, but ignoring the real indenter-sample interaction.
[0004] Therefore, there is an urgent need to provide a method, device, molecular dynamics simulation equipment and medium for constructing diamond indenter models to solve the problem of abnormal deformation of diamond indenter models, so as to minimize the impact of indenter deformation on simulation results while maintaining the simulation realism and research capability under extreme conditions. Summary of the Invention
[0005] In view of this, it is necessary to provide a method, apparatus, molecular dynamics simulation equipment and medium for constructing a diamond indenter model, in order to solve the technical problem of abnormal deformation of cubic diamond due to anisotropy in the prior art.
[0006] To address the aforementioned technical problems, in a first aspect, the present invention provides a method for constructing a diamond indenter model, comprising: The basic macroscopic parameters of the diamond indenter model are set; the basic macroscopic parameters include the geometry, lattice type, equivalent cone angle, vertex coordinates, and height of different temperature control zones of the diamond indenter model; Multiple temperature control zones of the diamond indenter model are determined based on the equivalent cone angle, the vertex coordinates, and the heights of the different temperature control zones. Determine the unit cell and initial basis vectors of the diamond indenter model, and rotate the crystal orientation of the diamond indenter model to the target crystal orientation with the strongest resistance to deformation based on the initial basis vectors; By filling the temperature-controlled region with carbon atoms according to the unit cell structure, a target diamond indenter model is obtained.
[0007] In one possible implementation, the geometry is a symmetrical triangular pyramid, and the lattice type is a hexagonal crystal system.
[0008] In one possible implementation, the heights of the different temperature-controlled zones include a fixed layer height, an isothermal layer height, and a Newtonian layer height; the multiple temperature-controlled regions include a Newtonian layer region, an isothermal region, and a fixed layer region; determining the multiple temperature-controlled regions of the diamond indenter model based on the equivalent cone angle, the vertex coordinates, and the heights of the different temperature-controlled zones includes: Based on the equivalent cone angle, determine the face normal vectors of the three facets in the diamond indenter model, and determine the first preset unit vector and the second preset unit vector that are perpendicular to the bottom surface of the diamond indenter model. Based on the fixed layer height, isothermal layer height, and Newton layer height, the first transition interface between the Newton layer and the isothermal layer, the second transition interface between the isothermal layer and the fixed layer, and the bottom surface of the fixed layer on the side away from the Newton layer are determined. The Newtonian layer region, the isothermal layer region, and the fixed layer region are determined based on the first transition interface, the second transition interface, the bottom surface, the vertex coordinates, the facet normal vector, the first preset unit vector, and the second preset unit vector.
[0009] In one possible implementation, determining the Newtonian layer region, the isothermal layer region, and the fixed layer region based on the first transition interface, the second transition interface, the bottom surface, the vertex coordinates, the edge normal vector, the first preset unit vector, and the second preset unit vector includes: Calculate the first, second, and third face regions formed by the vertex coordinates and the edge normal vectors; Determine the fourth and fifth surface regions formed by the coordinates of any point on the first transition interface and the first and second preset unit vectors. Determine the sixth and seventh surface regions formed by the coordinates of any point on the second transition interface and the first and second preset unit vectors. Determine the eighth surface region formed by the coordinates of any point on the bottom surface and the first preset unit vector; The intersection of the first surface region, the second surface region, the third surface region, and the fourth surface region is defined as the Newtonian layer region; the intersection of the first surface region, the second surface region, the third surface region, the fifth surface region, and the sixth surface region is defined as the isothermal layer region; and the intersection of the first surface region, the second surface region, the third surface region, the seventh surface region, and the eighth surface region is defined as the fixed layer region.
[0010] In one possible implementation, rotating the crystal orientation of the diamond indenter model to the target crystal orientation with the strongest resistance to deformation based on the initial basis vectors includes: Determine the target basis vectors for the target crystal orientation, and determine the rotation matrix based on the target basis vectors and the initial basis vectors; The crystal orientation of the diamond indenter model is rotated to the target crystal orientation based on the rotation matrix.
[0011] In one possible implementation, the step of filling the temperature-controlled region with carbon atoms according to the unit cell structure to obtain the target diamond indenter model includes: The relative coordinates of the carbon atoms with respect to the initial basis vectors are determined based on the unit cell structure. The carbon atoms are then filled into the temperature-controlled region based on the relative coordinates to obtain the target diamond indenter model.
[0012] In one possible implementation, the method further includes: Nanoindentation simulations were performed based on the target diamond indenter model and the cubic diamond indenter model, and the first simulation results and the second simulation results were obtained respectively. When the relative relationship between the first simulation result and the second simulation result conforms to the theoretical relative relationship, the target diamond indenter model is determined to be effective.
[0013] Secondly, the present invention also provides a diamond indenter model building device, comprising: The basic macroscopic parameter setting unit is used to set the basic macroscopic parameters of the diamond indenter model; the basic macroscopic parameters include the geometry, lattice type, equivalent cone angle, vertex coordinates, and height of different temperature control zones of the diamond indenter model; A temperature control region determination unit is used to determine multiple temperature control regions of the diamond indenter model based on the equivalent cone angle, the vertex coordinates, and the heights of the different temperature control regions. A crystal orientation adjustment unit is used to determine the unit cell of the diamond indenter model and the initial basis vectors of the unit cell, and to rotate the crystal orientation of the diamond indenter model to the target crystal orientation based on the initial basis vectors. Carbon atom filling units are used to fill the temperature-controlled region with carbon atoms according to the unit cell structure to obtain the target diamond indenter model.
[0014] Thirdly, the present invention also provides a molecular dynamics simulation device, including a memory and a processor, wherein, The memory is used to store programs; The processor, coupled to the memory, is used to execute the program stored in the memory to implement the steps in the diamond indenter model construction method described in any of the above possible implementations.
[0015] Fourthly, the present invention also provides a computer-readable storage medium for storing a computer-readable program or instructions, which, when executed by a processor, can implement the steps in the diamond indenter model construction method described in any of the above possible implementations.
[0016] The beneficial effects of this invention are as follows: The diamond indenter model construction method provided by this invention determines the unit cell and initial basis vectors of the diamond indenter model, and rotates the crystal orientation of the diamond indenter model to the target crystal orientation with the strongest resistance to deformation based on the initial basis vectors. In other words, the custom crystal orientation of the diamond indenter model provides the ability to actively control the performance of the indenter. By selecting and rotating to the target crystal orientation, the diamond indenter model can be made to have the strongest resistance to deformation, thereby ensuring that the mechanical response obtained by the simulation of the diamond indenter model is the mechanical response of the sample itself, rather than the failure behavior of the indenter. This solves the problem of abnormal deformation of the diamond indenter model in the molecular dynamics simulation process.
[0017] Furthermore, this invention divides the diamond indenter model into multiple temperature-controlled zones to construct a non-rigid diamond indenter model, which is more realistic compared to the rigid assumption in the prior art. Attached Figure Description
[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0019] Figure 1 A schematic flowchart of an embodiment of the diamond indenter model construction method provided by the present invention; Figure 2 A schematic diagram of an embodiment of the hexagonal diamond Berkovich indenter provided by the present invention; Figure 3 A schematic diagram of a unit cell structure of the diamond indenter model provided by the present invention; Figure 4 For the present invention Figure 1 A schematic diagram of an embodiment of step S102; Figure 5 For the present invention Figure 4 A schematic diagram of an embodiment of step S403; Figure 6 For the present invention Figure 1 A schematic flowchart of an embodiment of step S103; Figure 7A schematic flowchart of an embodiment for determining the validity of a target diamond indenter model provided by the present invention; Figure 8 A schematic diagram of an embodiment of the diamond indenter model loading a SiC substrate nanoindentation model provided by the present invention; Figure 9 Displacement-load curves of SiC substrate nanoindentation simulation for cubic diamond and target diamond indenter models provided in this invention; Figure 10 A schematic diagram of an embodiment of the diamond indenter model building device provided by the present invention; Figure 11 This is a schematic diagram of an embodiment of the molecular dynamics simulation device provided by the present invention. Detailed Implementation
[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.
[0021] It should be understood that the schematic drawings are not drawn to scale. The flowcharts used in this invention illustrate operations implemented according to some embodiments of the invention. It should be understood that the operations in the flowcharts may be implemented out of order, and steps without logical contextual relationships may be reversed or performed simultaneously. Furthermore, those skilled in the art, guided by the content of this invention, may add one or more other operations to the flowcharts, or remove one or more operations from the flowcharts. Some block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities may be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.
[0022] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.
[0023] This invention provides a method, apparatus, molecular dynamics simulation equipment, and medium for constructing a diamond indenter model, which will be described below.
[0024] Figure 1 This is a schematic flowchart of an embodiment of the diamond indenter model construction method provided by the present invention, as shown below. Figure 1 As shown, the method for constructing a diamond indenter model includes: S101. Set the basic macroscopic parameters of the diamond indenter model; the basic macroscopic parameters include the geometry, lattice type, equivalent cone angle, vertex coordinates, and height of different temperature control zones of the diamond indenter model.
[0025] To further improve the deformation resistance of the diamond indenter model, in a specific embodiment of the present invention, the geometry is a symmetrical triangular pyramid and the crystal lattice type is hexagonal, that is, the diamond indenter model is a hexagonal diamond Berkovich indenter.
[0026] The hexagonal diamond Berkovich indenter has better isotropy, which further improves the compressive strength of the diamond indenter and avoids abnormal deformation.
[0027] Then as Figure 2 As shown, the hexagonal diamond Berkovich indenter comprises a Newtonian layer, an isothermal layer, and a fixing layer. Atoms in the Newtonian layer move freely according to Newtonian mechanics, engaging in realistic, bidirectional mechanical interactions with the sample. Atoms in the isothermal layer are temperature-controlled to simulate heat dissipation in a real indenter, preventing heat buildup from affecting the results. The atoms in the fixing layer are completely fixed, simulating the portion held by the fixture and providing a fulcrum for loading.
[0028] S102. Determine multiple temperature control zones of the diamond indenter model based on the equivalent cone angle, vertex coordinates, and the height of different temperature control zones.
[0029] In a specific embodiment of the present invention, the equivalent cone angle can be determined by the facet angle, that is, the angle between the facet and the central axis. Specifically, the relationship between the equivalent cone angle and the facet angle satisfies:
[0030] In the formula, It is the equivalent cone angle; The angle of the facet.
[0031] S103. Determine the unit cell and initial basis vectors of the diamond indenter model, and rotate the crystal orientation of the diamond indenter model to the target crystal orientation with the strongest resistance to deformation based on the initial basis vectors.
[0032] In this invention, the unit cell is the smallest repeating unit in the diamond indenter model. In a specific embodiment of the invention, the structure of the unit cell is as follows: Figure 3 As shown, its lattice constant is 4.629, and its initial basis vectors are... (1,0,0) (0,0.577,0) (0,0,1). By adjusting the initial basis vectors, the crystal orientation can be arbitrarily set without changing the indentation direction.
[0033] S104. Fill the temperature-controlled region with carbon atoms according to the unit cell structure to obtain the target diamond indenter model.
[0034] In this embodiment of the invention, carbon atoms are filled after the crystal orientation is adjusted, rather than filling carbon atoms first and then adjusting the crystal orientation. This avoids the computational burden of rotating a large number of carbon atoms and improves computational efficiency.
[0035] It should be understood that the diamond indenter model construction method in this embodiment of the invention can be implemented in any device based on the diamond indenter model construction method, such as a molecular dynamics simulation device based on the diamond indenter model construction. Specifically, the diamond indenter model construction method is stored in the aforementioned device as a pre-programmed program. When the device is started, the program is invoked, and the diamond indenter model construction method is implemented.
[0036] Compared with existing technologies, the diamond indenter model construction method provided in this invention determines the unit cell and initial basis vectors of the diamond indenter model, and rotates the crystal orientation of the diamond indenter model to the target crystal orientation with the strongest resistance to deformation based on the initial basis vectors. This achieves a custom crystal orientation for the diamond indenter model. In other words, the custom crystal orientation provides active control over the indenter performance. By selecting and rotating to the target crystal orientation, the diamond indenter model can be made to have the strongest resistance to deformation, thereby ensuring that the mechanical response simulated by the diamond indenter model is the mechanical response of the sample itself, rather than the failure behavior of the indenter. This solves the problem of abnormal deformation of the diamond indenter model in the molecular dynamics simulation process.
[0037] Furthermore, in this embodiment of the invention, the diamond indenter model is divided into multiple temperature-controlled zones to construct a non-rigid diamond indenter model, which is more in line with reality compared to the rigid assumption in the prior art.
[0038] In specific embodiments of the present invention, such as Figure 2 As shown, the height of different temperature control zones includes the fixed layer height h. f Isotherm height h t and fixed layer height hh f -h t Where h is the overall height of the diamond indenter model. Then, as... Figure 4 As shown, step S102 includes: S401. Determine the face normal vectors of the three facets in the diamond indenter model based on the equivalent cone angle, and determine the first preset unit vector and the second preset unit vector that are perpendicular to the bottom surface of the diamond indenter model.
[0039] Specifically, the edge normal vector is determined based on the established coordinate system, which is a spatial rectangular coordinate system with the center of the bottom surface as the origin, the bottom surface as the xy plane, the z-axis passing through the vertex, and an edge in the yz plane.
[0040] Specifically, the normal vectors of the three facets are respectively (sin ,0,-cos ), (- sinθ, sin ,-cos ), (- sin ,- sin ,-cos ), all pointing towards the center of the body.
[0041] In the coordinate system described above, the first preset unit vector and the second preset unit vector are respectively (0,0,-1) (0,0,1).
[0042] S402. Determine the first transition interface between the Newton layer and the isotherm, the second transition interface between the isotherm and the fixed layer, and the bottom surface of the fixed layer away from the Newton layer based on the fixed layer height, the isotherm height, and the Newton layer height. S403. Based on the first transition interface, the second transition interface, the bottom surface, the vertex coordinates, the edge normal vector, the first preset unit vector, and the second preset unit vector, determine the Newtonian layer region, the isothermal layer region, and the fixed layer region.
[0043] The principle of determining a surface region based on points and vectors is as follows: A surface region is determined by a point A(a1,a2,a3) and a vector... (m1, m2, m3) can determine the path through point A. The plane with normal vector is: , and The region on one side separated by a plane, pointing in the positive direction, is called the region between A and... The area formed by the surface.
[0044] For example, if an atom belongs to the Newtonian layer, the atom must simultaneously satisfy the condition of being located inside three facets and above the first transition interface. Based on this region division principle, in a specific embodiment of the present invention, such as... Figure 5 As shown, step S403 includes: S501. Calculate the first, second, and third face regions formed by the vertex coordinates and the edge normal vectors. S502. Determine the fourth and fifth surface regions formed by the coordinates of any point on the first transition interface and the first and second preset unit vectors.
[0045] Where the vertex coordinates are (p x ,p y ,p z When ), the coordinates of any point on the first transition interface are (p x ,p y ,p z +hh f -h t ).
[0046] S503. Determine the sixth and seventh surface regions formed by the coordinates of any point on the second transition interface and the first and second preset unit vectors.
[0047] Where the vertex coordinates are (p x ,p y ,p z When ), the coordinates of any point on the second transition interface are (p x ,p y ,p z +hh f ).
[0048] S504. Determine the eighth surface region formed by the coordinates of any point on the bottom surface and the first preset unit vector.
[0049] Where the vertex coordinates are (p x ,p y ,p z When ), the coordinates of any point on the bottom surface are (p) x ,p y ,p z +h).
[0050] S505. The intersection of the first, second, third, and fourth surface regions is defined as the Newtonian layer region; the intersection of the first, second, third, fifth, and sixth surface regions is defined as the isothermal layer region; and the intersection of the first, second, third, seventh, and eighth surface regions is defined as the fixed layer region.
[0051] In this embodiment of the invention, a half-space is defined by a point and a normal vector. By performing an intersection operation on multiple half-spaces, multiple closed geometric bodies can be divided. All atoms within the geometric body are assigned the same property to determine whether it belongs to a Newtonian layer, an isothermal layer, or a fixed layer.
[0052] In some embodiments of the present invention, such as Figure 6 As shown, step S103, which involves rotating the crystal orientation of the diamond indenter model to the target crystal orientation with the strongest resistance to deformation based on the initial basis vectors, includes: S601. Determine the target basis vectors for the target crystal orientation, and determine the rotation matrix based on the target basis vectors and the initial basis vectors.
[0053] In a specific embodiment of the present invention, if the rotation axis of the unit cell is u(u x ,u y ,u z ) If the rotation angle is θ, then the rotation matrix R is: .
[0054] S602. Rotate the crystal orientation of the diamond indenter model to the target crystal orientation based on the rotation matrix.
[0055] Specifically, the target crystal orientation, i.e., the rotated basis vector, is .
[0056] In a specific embodiment of the present invention, step S104 specifically includes: The relative coordinates of carbon atoms to the initial basis vectors are determined based on the unit cell structure. Based on the relative coordinates, carbon atoms are filled into the temperature-controlled region to obtain the target diamond indenter model.
[0057] In a specific embodiment of the present invention, the unit cell comprises 8 carbon atoms, whose relative coordinates to the initial basis vectors are (0,0,0), (0.5,0.5,0), (0.333,0,0.167), (0.833,0.5,0.167), (0.333,0,0.5), (0.833,0.5,0.5), (0,0,0.667), (0.5,0.5,0.667).
[0058] To verify the reliability and effectiveness of the diamond indenter model constructed in the embodiments of the present invention, in some embodiments of the present invention, such as Figure 7 As shown, it also includes: S701. Nanoindentation simulation was performed based on the target diamond indenter model and the cubic diamond indenter model, and the first simulation result and the second simulation result were obtained respectively.
[0059] Specifically, such as Figure 8As shown, 3C-SiC was used as the substrate, with periodic boundaries (p) in the x and y directions and a fixed boundary (f) in the z direction. The SiC substrate was cubic in shape, consisting of a fixed layer, an isothermal layer, and a Newtonian layer. The overall situation function was set as the Tersoff potential. Energy minimization was performed using the conjugate gradient method (cg), followed by full relaxation under the NVE ensemble. The indenter was moved linearly to the maximum depth at a velocity v, held at the lowest point for t seconds, and then unloaded back to the initial position at a velocity v. The displacement of the indenter and the resultant force in the z direction were output during the indentation process, and the displacement-load curve was plotted. The simulation was repeated using a cubic diamond indenter model for comparison, and the results are shown below. Figure 9 As shown, Figure 9 The blue curve represents the first simulation result, the red curve represents the second simulation result, the blue discrete point represents the unloading start point of the target diamond indenter model, and the red discrete point represents the unloading start point of the cubic diamond indenter model.
[0060] S702. When the relative relationship between the first simulation result and the second simulation result conforms to the theoretical relative relationship, the target diamond indenter model is determined to be valid.
[0061] Specifically, theoretically, the compressive strength of the target diamond indenter model is greater than that of the cubic diamond indenter model, that is, under the same load... Figure 9 The displacement of the blue curve should be less than the displacement of the red curve. If this condition is met, the target diamond indenter model is valid; otherwise, it is invalid.
[0062] By comparing the two, the effectiveness of the constructed diamond indenter model can be ensured in this embodiment of the invention.
[0063] Furthermore, in addition to directly comparing curves, for quantitative comparison, in a specific embodiment of the present invention, the difference between the hardness and Young's modulus of the tested material can be compared by calculating the two, further illustrating the effectiveness of the diamond indenter model construction method of the present invention.
[0064] Specifically, calculate the hardness and Young's modulus. The hardness of the substrate material is calculated using the following formula. H :
[0065] in, P max For maximum load, A c The contact projection area.
[0066] For the Berkovich indenter, the contact projected area A cThe following formula can be used to calculate:
[0067] Among them, h max This represents the maximum loading depth.
[0068] The Young's modulus of the substrate material is derived by inverse calculation using the equivalent modulus. The formula for calculating the equivalent modulus Eeff is as follows:
[0069] in, The indenter geometry correction factor is 1.034 (typically used for Berkovich indenters), S is the contact stiffness, and the slope of the initial segment of the unloading curve is denoted as . Therefore, the relationship between Young's modulus E and the equivalent modulus Eeff is expressed by the following formula:
[0070] Where v is the Poisson's ratio of the substrate material, v i E is the Poisson's ratio of the indenter material. i This is the Young's modulus of the indenter material.
[0071] The results obtained from the calculations are shown in Table 1: Table 1. Hardness and Young's modulus of 3C-SiC obtained by simulation testing using two diamond indenter models.
[0072] As shown in Table 1, the hardness of 3C-SiC obtained by simulation testing using the target diamond indenter model in this embodiment of the invention is lower than that obtained using the cubic diamond indenter model, while the Young's modulus is the opposite. This is because the cubic diamond indenter model undergoes elastoplastic deformation under high pressure, resulting in a smaller contact area and a systematic overestimation of hardness; simultaneously, the indenter deformation interferes with the unloading response, causing contact stiffness errors and a systematic underestimation of Young's modulus. The hexagonal diamond indenter model has extremely high hardness, greatly suppressing its own deformation, and is closer to a "rigid indenter," thus the results better reflect the intrinsic properties of the material.
[0073] In summary, the diamond indenter model construction method proposed in this embodiment of the invention has the following properties: 1. It adopts a Berkovich indenter, which has a symmetrical triangular pyramidal geometry, closer to actual experimental conditions than spherical or conical indenters. 2. The Berkovich indenter allows bidirectional mechanical interaction between the indenter and the sample, and can simulate the vibration or energy dissipation of the indenter itself, reflecting contact mechanics (such as contact area and stress distribution) more realistically. 3. The equivalent cone angle of the indenter model can be arbitrarily defined, and the crystal orientation of hexagonal diamond (such as the
[001] plane or the
[111] plane) can be arbitrarily selected, increasing experimental matching, computational controllability, and flexibility in mechanism research. 4. According to the comparison of the displacement-load curves of the indentation simulation of SiC substrate by the hexagonal diamond indenter model and the cubic diamond indenter model, it can be seen that during the loading stage, the indentation depth of hexagonal diamond is greater under the same load, indicating that the hardness of hexagonal diamond is greater than that of cubic diamond, which is consistent with the actual situation.
[0074] On the other hand, embodiments of the present invention also provide a diamond indenter model building device, such as... Figure 10 As shown, the diamond indenter model building device 1000 includes: The basic macroscopic parameter setting unit 1001 is used to set the basic macroscopic parameters of the diamond indenter model. The basic macroscopic parameters include the geometry, lattice type, equivalent cone angle, vertex coordinates, and height of different temperature control zones of the diamond indenter model. Temperature control region determination unit 1002 is used to determine multiple temperature control regions of the diamond indenter model based on the equivalent cone angle, vertex coordinates and the height of different temperature control regions; The crystal orientation adjustment unit 1003 is used to determine the unit cell and the initial basis vector of the diamond indenter model, and rotate the crystal orientation of the diamond indenter model to the target crystal orientation based on the initial basis vector. The carbon atom filling unit 1004 is used to fill the temperature-controlled region with carbon atoms according to the unit cell structure to obtain the target diamond indenter model.
[0075] The diamond indenter model building device 1000 provided in the above embodiments can realize the technical solutions described in the above diamond indenter model building method embodiments. The specific implementation principles of each module or unit can be found in the corresponding content in the above diamond indenter model building method embodiments, and will not be repeated here.
[0076] like Figure 11 As shown, the present invention also provides a molecular dynamics simulation device 1100. The molecular dynamics simulation device 1100 includes a processor 1101, a memory 1102, and a display 1103. Figure 11Only a portion of the components of the molecular dynamics simulation apparatus 1100 are shown; however, it should be understood that implementation of all shown components is not required, and more or fewer components may be implemented instead.
[0077] In some embodiments, processor 1101 may be a central processing unit (CPU), a microprocessor, or other data processing chip, used to run program code stored in memory 1102 or process data, such as the diamond indenter model construction method of the present invention.
[0078] In some embodiments, memory 1102 may be an internal storage unit of the molecular dynamics simulation device 1100, such as a hard disk or memory of the molecular dynamics simulation device 1100. In other embodiments, memory 1102 may also be an external storage device of the molecular dynamics simulation device 1100, such as a pluggable hard disk, smart media card (SMC), secure digital (SD) card, flash card, etc., equipped on the molecular dynamics simulation device 1100.
[0079] In some embodiments, display 1103 may be an LED display, a liquid crystal display, a touch-screen liquid crystal display, or an OLED (Organic Light-Emitting Diode) touchscreen. Display 1103 is used to display information from the molecular dynamics simulation device 1100 and to display a user interface for visualization. Components 1101-1104 of the molecular dynamics simulation device 1100 communicate with each other via a device bus.
[0080] In some embodiments of the present invention, when the processor 1101 executes the diamond indenter model construction program in the memory 1102, the following steps can be performed: Set the basic macroscopic parameters of the diamond indenter model; the basic macroscopic parameters include the geometry, lattice type, equivalent cone angle, vertex coordinates, and height of different temperature control zones of the diamond indenter model; Multiple temperature control zones of the diamond indenter model are determined based on the equivalent cone angle, vertex coordinates, and the height of different temperature control zones. Determine the unit cell and initial basis vectors of the diamond indenter model, and rotate the crystal orientation of the diamond indenter model to the target crystal orientation with the strongest resistance to deformation based on the initial basis vectors; By filling the temperature-controlled region with carbon atoms according to the unit cell structure, a target diamond indenter model is obtained.
[0081] It should be understood that when the processor 1101 executes the diamond indenter model construction program in the memory 1102, in addition to the functions mentioned above, it can also perform other functions, as detailed in the description of the corresponding method embodiments above.
[0082] Those skilled in the art will understand that all or part of the processes of the methods described in the above embodiments can be implemented by a computer program instructing related hardware (such as a processor, controller, etc.), and the computer program can be stored in a computer-readable storage medium. The computer-readable storage medium may be a disk, optical disk, read-only memory, or random access memory, etc.
[0083] The above provides a detailed description of the diamond indenter model construction method, apparatus, molecular dynamics simulation equipment, and medium provided by the present invention. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.
Claims
1. A method for constructing a diamond indenter model, characterized in that, include: Set the basic macroscopic parameters of the diamond indenter model; The basic macroscopic parameters include the geometry, lattice type, equivalent cone angle, vertex coordinates, and height of different temperature control zones of the diamond indenter model. Multiple temperature control zones of the diamond indenter model are determined based on the equivalent cone angle, the vertex coordinates, and the heights of the different temperature control zones. Determine the unit cell and initial basis vectors of the diamond indenter model, and rotate the crystal orientation of the diamond indenter model to the target crystal orientation with the strongest resistance to deformation based on the initial basis vectors; By filling the temperature-controlled region with carbon atoms according to the unit cell structure, a target diamond indenter model is obtained.
2. The method for constructing a diamond indenter model according to claim 1, characterized in that, The geometry is a symmetrical triangular pyramid, and the crystal lattice type is a hexagonal crystal system.
3. The method for constructing a diamond indenter model according to claim 2, characterized in that, The heights of the different temperature control zones include a fixed layer height, an isothermal layer height, and a Newtonian layer height; the multiple temperature control regions include a Newtonian layer region, an isothermal layer region, and a fixed layer region; determining the multiple temperature control regions of the diamond indenter model based on the equivalent cone angle, the vertex coordinates, and the heights of the different temperature control zones includes: Based on the equivalent cone angle, determine the face normal vectors of the three facets in the diamond indenter model, and determine the first preset unit vector and the second preset unit vector that are perpendicular to the bottom surface of the diamond indenter model. Based on the fixed layer height, isothermal layer height, and Newton layer height, the first transition interface between the Newton layer and the isothermal layer, the second transition interface between the isothermal layer and the fixed layer, and the bottom surface of the fixed layer on the side away from the Newton layer are determined. The Newtonian layer region, the isothermal layer region, and the fixed layer region are determined based on the first transition interface, the second transition interface, the bottom surface, the vertex coordinates, the facet normal vector, the first preset unit vector, and the second preset unit vector.
4. The method for constructing a diamond indenter model according to claim 3, characterized in that, The step of determining the Newtonian layer region, the isothermal layer region, and the fixed layer region based on the first transition interface, the second transition interface, the bottom surface, the vertex coordinates, the facet normal vector, the first preset unit vector, and the second preset unit vector includes: Calculate the first, second, and third face regions formed by the vertex coordinates and the edge normal vectors; Determine the fourth and fifth surface regions formed by the coordinates of any point on the first transition interface and the first and second preset unit vectors. Determine the sixth and seventh surface regions formed by the coordinates of any point on the second transition interface and the first and second preset unit vectors. Determine the eighth surface region formed by the coordinates of any point on the bottom surface and the first preset unit vector; The intersection of the first surface region, the second surface region, the third surface region, and the fourth surface region is defined as the Newtonian layer region; the intersection of the first surface region, the second surface region, the third surface region, the fifth surface region, and the sixth surface region is defined as the isothermal layer region; and the intersection of the first surface region, the second surface region, the third surface region, the seventh surface region, and the eighth surface region is defined as the fixed layer region.
5. The method for constructing a diamond indenter model according to claim 1, characterized in that, The step of rotating the crystal orientation of the diamond indenter model to the target crystal orientation with the strongest resistance to deformation based on the initial basis vectors includes: Determine the target basis vectors for the target crystal orientation, and determine the rotation matrix based on the target basis vectors and the initial basis vectors; The crystal orientation of the diamond indenter model is rotated to the target crystal orientation based on the rotation matrix.
6. The method for constructing a diamond indenter model according to claim 1, characterized in that, The process of filling the temperature-controlled region with carbon atoms according to the unit cell structure to obtain the target diamond indenter model includes: The relative coordinates of the carbon atoms with respect to the initial basis vectors are determined based on the unit cell structure. The carbon atoms are then filled into the temperature-controlled region based on the relative coordinates to obtain the target diamond indenter model.
7. The method for constructing a diamond indenter model according to claim 1, characterized in that, The method further includes: Nanoindentation simulations were performed based on the target diamond indenter model and the cubic diamond indenter model, and the first simulation results and the second simulation results were obtained respectively. When the relative relationship between the first simulation result and the second simulation result conforms to the theoretical relative relationship, the target diamond indenter model is determined to be effective.
8. A diamond indenter model building device, characterized in that, include: The basic macroscopic parameter setting unit is used to set the basic macroscopic parameters of the diamond indenter model. The basic macroscopic parameters include the geometry, lattice type, equivalent cone angle, vertex coordinates, and height of different temperature control zones of the diamond indenter model. A temperature control region determination unit is used to determine multiple temperature control regions of the diamond indenter model based on the equivalent cone angle, the vertex coordinates, and the heights of the different temperature control regions. A crystal orientation adjustment unit is used to determine the unit cell of the diamond indenter model and the initial basis vectors of the unit cell, and to rotate the crystal orientation of the diamond indenter model to the target crystal orientation based on the initial basis vectors. Carbon atom filling units are used to fill the temperature-controlled region with carbon atoms according to the unit cell structure to obtain the target diamond indenter model.
9. A molecular dynamics simulation device, characterized in that, Including memory and processor, among which, The memory is used to store programs; The processor, coupled to the memory, is used to execute the program stored in the memory to implement the steps in the diamond indenter model construction method according to any one of claims 1 to 7.
10. A computer-readable storage medium, characterized in that, Used to store computer-readable programs or instructions, which, when executed by a processor, can implement the steps in the diamond indenter model construction method according to any one of claims 1 to 7.