Dhp-graphene tensile mechanical property molecular dynamics analysis method and system

Abstract

The application discloses a DHP-graphene tensile mechanical property molecular dynamics analysis method and system. The method comprises the following steps: constructing a DHP-graphene single-layer unit cell, performing supercell size convergence screening, and determining a representative model; setting a strain rate set, a temperature set and a defect set on the representative model, performing energy minimization, NPT relaxation and NVT uniaxial tension loading, and outputting stress-strain data and atomic local stress field in real time along the zigzag direction and the armchair direction respectively; extracting Young's modulus, ultimate stress, ultimate strain and toughness according to the output results, determining defect edge stress concentration, crack initiation position and expansion path, and obtaining anisotropic mechanical response and failure law of the DHP-graphene under different external working conditions and structural defect conditions. The application can provide a theoretical basis for reliability design of the DHP-graphene in nanoelectronic devices, energy packaging and lightweight structures.

Description

Technical Field

[0001] This application relates to the technical field of molecular dynamics simulation, mechanical analysis of two-dimensional carbon materials and reliability evaluation of nanostructures, and computer-aided design, and in particular to a molecular dynamics analysis method and system for the tensile mechanical properties of DHP-graphene considering the coupling effect of strain rate, temperature and defects. Background Technology

[0002] DHP-graphene is a novel two-dimensional carbon allotrope formed by the reconstruction of five-, six-, and ten-membered rings. It combines porous topology with high carbon framework integrity, making it a potential application in nanoelectronic devices, membrane separation, energy storage encapsulation, and lightweight functional structures. Compared to traditional graphene, its non-uniform ring structure and porosity offer a richer functional control space, but also significantly alter the load transfer path and local stress distribution.

[0003] In actual fabrication and service, DHP-graphene is often subjected to the combined effects of loading rate, ambient temperature, and geometric defects. These factors influence bond elongation, thermally activated fracture, stress concentration, and crack propagation, ultimately determining the material's strength, ductility, toughness, and failure mode. For two-dimensional materials intended for energy encapsulation and nanodevices, accurately assessing their mechanical reliability under coupled conditions is crucial.

[0004] Existing research largely focuses on the stability, electronic properties, and separation / energy storage applications of DHP-graphene, while systematic analysis of its tensile mechanical behavior under the combined effects of strain rate, temperature, and defects is lacking. Traditional experimental methods are insufficient to directly resolve crack initiation and non-equilibrium fracture processes at the atomic scale, and existing molecular dynamics studies often neglect the coupling effects of model size convergence, bidirectional anisotropy, and differences in defect morphology on the failure path.

[0005] Therefore, there is a need for a molecular dynamics analysis method and system that can uniformly complete size screening, parameter scanning, defect evaluation, and failure determination. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of existing technologies, such as unsystematic analysis of the tensile behavior of DHP-graphene under coupled working conditions, difficulty in eliminating the influence of size effects, and difficulty in quantitatively identifying defect failure paths. This invention provides a molecular dynamics analysis method and system for the tensile mechanical properties of DHP-graphene that considers the coupling effect of strain rate, temperature, and defects.

[0007] The technical solution provided in this application is as follows.

[0008] Firstly, it provides a molecular dynamics analysis method for the tensile mechanical properties of DHP-graphene, including: Based on the DHP-graphene monolayer unit cell model, a number of defect-free supercell models with different numbers of atoms were constructed and generated, with a vacuum layer set in the out-of-plane direction; Under preset temperature and reference strain rate conditions, uniaxial tensile simulations were performed on the multiple defect-free supercell models with different atomic numbers along the serrated direction and the armchair direction, respectively. The representative model size was determined based on the rate of change of ultimate stress, ultimate strain and toughness. Based on the representative model dimensions, molecular dynamics potential function, time step, relaxation condition, loading strain rate set, temperature set, and defect set are set; the defect set constitutes a defect-containing model. Energy minimization and isothermal and isobaric relaxation were performed on the defect-free model and the defective model respectively. Under the condition that the in-plane stress perpendicular to the loading direction is zero, uniaxial tensile loading was applied along the sawtooth direction or the armchair direction under isothermal conditions. During the stretching process, stress-strain data and atomic localized stress fields are output in real time, and Young's modulus, ultimate stress, ultimate strain and toughness are extracted based on the stress-strain data; Based on the changes in mechanical parameters under different loading strain rates, temperatures, defect types, and defect sizes, as well as the evolution of atomic local stress concentration, the crack initiation location and propagation path are determined, and the anisotropic mechanical response and defect tolerance evaluation results of DHP-graphene are obtained.

[0009] In one possible implementation, the DHP-graphene monolayer cell is composed of five-membered rings, six-membered rings, and ten-membered rings.

[0010] In one possible implementation, the method for determining the representative model size includes: When the rate of change of the ultimate stress, ultimate strain, and toughness of a defect-free supercell model with a certain number of atoms is lower than a threshold, and a balance is achieved between computational accuracy and computational cost, the model with the number of atoms is determined as the representative model size.

[0011] In one possible implementation, the set of loading strain rates is: to The temperature range is from 100 K to 500 K, and includes at least 100 K, 200 K, 300 K, 400 K and 500 K.

[0012] In one possible implementation, the set of defects includes at least rectangular cracks and circular holes.

[0013] In one possible implementation, the Young's modulus is obtained by linear fitting of the elastic phase of the stress-strain curve; the ultimate stress is the peak stress; the ultimate strain is the strain corresponding to structural instability or fracture; and the toughness is the integral area of ​​the stress-strain curve.

[0014] In one possible implementation, the crack initiation location and propagation path are determined by tracking the von Mises stress peak locations and bond breakage sequences of the defect edge atoms.

[0015] Secondly, it provides a molecular dynamics analysis device for the tensile mechanical properties of DHP-graphene, including: The building module is used to construct and generate multiple defect-free supercell models with different numbers of atoms based on the DHP-graphene monolayer unit cell model, and to set a vacuum layer in the out-of-plane direction; The representative model determination module is used to perform uniaxial tensile simulations on the multiple defect-free supercell models with different atomic numbers along the serrated direction and the armchair direction under preset temperature and reference strain rate conditions, and determine the representative model size based on the rate of change of ultimate stress, ultimate strain and toughness. The configuration module is used to set the molecular dynamics potential function, time step, relaxation condition, loading strain rate set, temperature set, and defect set based on the representative model size; the defect set constitutes a defect-containing model. The loading module is used to perform energy minimization and isothermal and isobaric relaxation on the defect-free model and the defective model respectively. Under the condition that the in-plane stress perpendicular to the loading direction is zero, uniaxial tensile loading is applied along the sawtooth direction or the armchair direction under isothermal conditions. The extraction module is used to output stress-strain data and atomic localized stress field in real time during the stretching process, and extract Young's modulus, ultimate stress, ultimate strain and toughness based on the stress-strain data; The output module is used to determine the crack initiation location and propagation path based on the changes in mechanical parameters under different loading strain rates, temperatures, defect types and sizes, as well as the evolution of atomic local stress concentration, and to obtain the anisotropic mechanical response and defect tolerance evaluation results of DHP-graphene.

[0016] Thirdly, an electronic device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the program, implements the molecular dynamics analysis method for the tensile mechanical properties of DHP-graphene as described in the first aspect.

[0017] Fourthly, a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the molecular dynamics analysis method for the tensile mechanical properties of DHP-graphene as described in the first aspect.

[0018] Compared with the prior art, this application has the following beneficial effects: 1. The method provided in this application can significantly reduce the interference of finite size effects on mechanical parameters and improve the reliability of simulation results by performing size convergence screening before formal analysis; 2. The method provided in this application unifies strain rate, temperature, defect type, defect size and bidirectional loading into the same molecular dynamics process, which can systematically reveal the anisotropic mechanical response of DHP-graphene; 3. The method provided in this application utilizes both global stress-strain parameters and local atomic stress evolution to quantitatively identify stress concentration at defect edges, crack initiation locations, and failure paths; 4. The method provided in this application unifies size effect elimination, parameter coupling analysis and defect tolerance assessment into the same simulation process, which can provide quantitative basis for the structural design and defect tolerance assessment of DHP-graphene in nanoelectronic devices, energy packaging and lightweight structures. Attached Figure Description

[0019] Figure 1 A schematic diagram of the molecular dynamics analysis method for the tensile mechanical properties of DHP-graphene provided in the embodiments of this application; Figure 2 A schematic diagram illustrating the construction and loading direction of the DHP-graphene model provided in this application embodiment; Figure 2 (a) is the unit cell topology; Figure 2 (b) is a top view of a representative supercell; Figure 2 (c) For three-dimensional modeling and the outer vacuum layer; Figure 3 A schematic diagram illustrating the configuration of rectangular cracks and circular holes provided in an embodiment of this application; Figure 3 (a) is a central rectangular crack; Figure 3 (b) is a central circular hole; Figure 4 A schematic diagram of the structure of the molecular dynamics analysis device for the tensile mechanical properties of DHP-graphene provided in the embodiments of this application; Figure 5 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Detailed Implementation

[0020] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0021] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0022] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this technology based on the specific circumstances.

[0023] In the description of this application, spatial relation terms such as "below," "under," "below," "below," "above," "over," etc., are used herein to describe the relationship between one element or feature shown in the figures and other elements or features. It should be understood that, in addition to the orientation shown in the figures, spatial relation terms also include different orientations of the device in use and operation. For example, if the device in the figures is flipped, an element or feature described as "below" or "under" or "below" of other elements or features will be oriented "above" other elements or features. Therefore, the exemplary terms "below" and "under" can include both upper and lower orientations. Furthermore, the device may also include other orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptive terms used herein are interpreted accordingly.

[0024] In the description of this application, the term "for example" is used to mean "used as an example, illustration, or description." Any embodiment described as "for example" in this application is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is provided to enable any person skilled in the art to make and use this application. Details are set forth in the following description for purposes of explanation. It should be understood that those skilled in the art will recognize that this application can be made without using these specific details. In other instances, well-known structures and processes will not be described in detail to avoid unnecessarily obscuring the description of this application. Therefore, this application is not intended to be limited to the embodiments shown, but is consistent with the broadest scope of the principles and features disclosed in this application.

[0025] Existing research lacks a systematic analysis of the tensile mechanical behavior of DHP-graphene under the combined effects of strain rate, temperature, and defects. Traditional experimental methods are insufficient to directly resolve crack initiation and non-equilibrium fracture processes at the atomic scale, while existing molecular dynamics studies often neglect the coupling effects of model size convergence, bidirectional anisotropy, and differences in defect morphology on the failure path.

[0026] Therefore, this application provides a molecular dynamics analysis method for the tensile mechanical properties of DHP-graphene.

[0027] See Figure 1 Molecular dynamics analysis methods for the tensile mechanical properties of DHP-graphene include: S101. Based on the DHP-graphene monolayer cell model, construct and generate multiple defect-free supercell models with different numbers of atoms, and set a vacuum layer in the out-of-plane direction.

[0028] In one possible implementation, the DHP-graphene monolayer cell is composed of five-membered rings, six-membered rings, and ten-membered rings.

[0029] In one possible implementation, S101 includes: firstly constructing a DHP-graphene monolayer cell composed of five-membered rings, six-membered rings, and ten-membered rings, and generating multiple defect-free supercell models with different numbers of atoms based on the monolayer cell, and setting a vacuum layer in the out-of-plane direction.

[0030] Specifically, the DHP-graphene monolayer cell contains 24 carbon atoms, belongs to the Cmm two-dimensional space group, and has an average C-C bond length of 0.1443 nm; the initial planar size of the supercell model is 42.90 nm × 42.97 nm, and the thickness of the out-of-plane vacuum layer is 14.16 nm.

[0031] S102. Under preset temperature and reference strain rate conditions, uniaxial tensile simulations are performed on the multiple defect-free supercell models with different atomic numbers along the serrated direction and the armchair direction, respectively, and the representative model size is determined based on the rate of change of ultimate stress, ultimate strain and toughness.

[0032] In one possible implementation, the method for determining the representative model size includes: When the rate of change of the ultimate stress, ultimate strain, and toughness of a defect-free supercell model with a certain number of atoms is lower than a threshold, and a balance is achieved between computational accuracy and computational cost, the model with the number of atoms is determined as the representative model size.

[0033] For example, the multiple defect-free supercell models with different numbers of atoms include models with 840, 3360, 7560, 15120, 29520, 63360, 99000, and 200304 atoms; when the number of atoms exceeds 29520, the rate of change of ultimate stress, ultimate strain, and toughness is less than 2%, and a balance is achieved between computational accuracy and computational cost, the model with 63360 atoms is determined as the representative model size.

[0034] Understandably, the purpose of S102 is to determine the representative model size. By performing size convergence screening before formal analysis, the interference of finite size effects on mechanical parameters can be significantly reduced, improving the reliability of simulation results. For example, a model with 63,360 atoms is determined as the representative model size. If the model size is smaller than this, interference from ultimate stress, ultimate strain, and toughness may occur in subsequent simulations, affecting the reliability of the results. If the model size is larger than this, the marginal effect of the rate of change of ultimate stress, ultimate strain, and toughness is significant, and the computational load and cost increase significantly, resulting in low returns.

[0035] S103. Based on the representative model size, set the molecular dynamics potential function, time step, relaxation condition, loading strain rate set, temperature set, and defect set; the defect set constitutes a defect-containing model.

[0036] In one possible implementation, the molecular dynamics potential function includes the AIREBO and Morse potential functions.

[0037] For example, the CC interaction cutoff distance is set to 0.192 nm, the time step is set to 0.001 ps, the isothermal and isobaric relaxation time is 40 ps, ​​and the reference strain rate is 0.001 ps^-1.

[0038] In one possible implementation, the loading strain rate is the engineering strain rate applied along the loading direction when a uniaxial tensile load is applied, and the set is as follows: to The temperature range is from 100 K to 500 K, and includes at least 100 K, 200 K, 300 K, 400 K and 500 K.

[0039] In one possible implementation, the set of defects includes at least rectangular cracks and circular holes.

[0040] Specifically, the rectangular crack is arranged at the center of the model, with the short side fixed at 1 nm and the long side ranging from 1 nm to 4 nm, and the long side is perpendicular to the loading direction; the circular hole is arranged at the center of the model, with a diameter ranging from 1 nm to 4 nm.

[0041] S104. Perform energy minimization and isothermal and isobaric relaxation on the defect-free model and the defective model respectively. Under the condition that the in-plane stress perpendicular to the loading direction is zero, perform uniaxial tensile loading along the sawtooth direction or armchair direction under isothermal conditions.

[0042] In one possible implementation, the energy minimization method includes: The conjugate gradient method is used to minimize the energy of both defect-free and defective models in order to eliminate local high-energy overlap and unreasonable bond lengths in the initial configuration and obtain a stable stretched initial configuration.

[0043] Furthermore, the method for minimizing energy includes: (1) The conjugate gradient algorithm is used to iteratively optimize the DHP-graphene monolayer atomic model. The potential energy decrease path is searched according to the gradient direction of the total potential energy of the system with respect to the atomic coordinates, and a conjugate relationship is constructed between adjacent iteration directions to improve the convergence efficiency. (2) When the total energy change of the system is less than the preset energy threshold and the residual force of each atom is less than the preset force threshold, the energy minimization is determined to be completed, thereby obtaining the optimized structure after removing the local high-energy configuration and non-physical overlap.

[0044] In one possible implementation, the isothermal and isobaric relaxation conditions are as follows: At a preset temperature, the NPT ensemble is used for relaxation for 40 ps, ​​and the in-plane pressure perpendicular to the loading direction is controlled to be 0 to release the initial residual stress. After relaxation, the system is switched to the NVT ensemble, and a uniaxial tensile load is applied along the predetermined loading direction while keeping the temperature constant.

[0045] S105. During the stretching process, output stress-strain data and atomic localized stress field in real time, and extract Young's modulus, ultimate stress, ultimate strain and toughness based on the stress-strain data.

[0046] In one possible implementation, the Young's modulus is obtained by linear fitting of the elastic phase of the stress-strain curve; the ultimate stress is the peak stress; the ultimate strain is the strain corresponding to structural instability or fracture; and the toughness is the integral area of ​​the stress-strain curve.

[0047] It should be noted that the localized stress field of atoms reflects the local stress state and spatial distribution of each atom during the loading process. By tracking the formation, migration and expansion of localized high-stress regions, it can help determine the stress concentration location at the defect edge, the crack initiation time, and the subsequent expansion path.

[0048] S106. Based on the changes in mechanical parameters under different strain rates, temperatures, defect types, and defect sizes, as well as the evolution of atomic local stress concentration, the crack initiation location and propagation path are determined, and the anisotropic mechanical response and defect tolerance evaluation results of DHP-graphene are obtained.

[0049] In one possible implementation, the crack initiation location and propagation path are determined by tracking the von Mises stress peak locations and bond breakage sequences of the defect edge atoms.

[0050] The method provided in this application implements a systematic analysis of the tensile mechanical properties of DHP-graphene through a process of "model construction—size convergence screening—parameter and defect setting—relaxation and tensile loading—data extraction—failure assessment." Specifically, size convergence screening is used to reduce the influence of finite size effects on ultimate stress, ultimate strain, and toughness; parameter and defect setting is used to construct defect-free and defect-containing models under different working conditions; tensile loading and data extraction are used to obtain stress-strain curves and atomic localized stress fields; and failure assessment is used to determine crack initiation locations, propagation paths, and defect tolerance evaluation results.

[0051] The following detailed embodiments illustrate this point.

[0052] Example 1 like Figure 1 As shown, this embodiment provides a molecular dynamics analysis method for the tensile mechanical properties of DHP-graphene considering the coupling effects of strain rate, temperature, and defects. This method can be implemented in the LAMMPS molecular dynamics platform and can be combined with post-processing tools such as OVITO for visualization of atomic configuration and local stress.

[0053] Step S1: Construct DHP-graphene monolayer unit cell and multi-scale supercell models.

[0054] See Figure 2The monolayer unit cell is composed of five-membered, six-membered, and ten-membered rings, with each unit cell containing 24 carbon atoms, belonging to the Cmm two-dimensional space group, and an average C-C bond length of approximately 0.1443 nm. Based on equilibrium structural parameters, several defect-free supercell models with different atomic numbers were constructed, namely 840, 3360, 7560, 15120, 29520, 63360, 99000, and 200304. The preferred initial planar size is 42.90 nm × 42.97 nm, with a 14.16 nm vacuum layer in the out-of-plane direction to avoid non-physical interactions between periodic images. Step S2: Perform size convergence screening. The multiple defect-free supercell models obtained in step S1 were subjected to a loading strain rate of 0.001 K at 300 K. Uniaxial tension was applied along both the sawtooth and armchair directions under the specified conditions. By comparing the trends of ultimate stress, ultimate strain, and toughness, it was found that the stress-strain curves in the elastic stage largely overlapped, and Young's modulus was insensitive to size. As the number of atoms increased, the dispersion in the fracture stage gradually decreased. When the number of atoms exceeded 29520, the rates of change of ultimate stress, ultimate strain, and toughness were all below 2%, indicating that the model had essentially converged. Considering both computational accuracy and cost, a supercell model with 63360 atoms was selected as the representative model size.

[0055] In a preferred embodiment, the dimensional convergence results are as follows: along the serration direction, the ultimate stress decreases from 62.61 GPa and converges to 56.34 GPa, the ultimate strain decreases from 0.1914 and converges to 0.1385, and the toughness decreases from 8.42 GPa and converges to 4.92 GPa; along the armchair direction, the ultimate stress decreases from 63.22 GPa and converges to 60.70 GPa, the ultimate strain decreases from 0.1612 and converges to 0.1416, and the toughness decreases from 6.50 GPa and converges to 5.17 GPa. These results demonstrate that performing dimensional screening before formal parameter analysis effectively avoids overestimation of nominal strength and ductility in small-sized models.

[0056] Step S3: Set molecular dynamics and defect parameters. Interatomic interactions are described using the AIREBO / Morse potential function, with the CC interaction cutoff distance set to 0.192 nm and the time step set to 0.001 ps. The model first performs energy minimization, then relaxes for 40 ps in the NPT ensemble to release the initial residual stress, followed by uniaxial stretching in the NVT ensemble. Except for specific studies of strain rate effects, the reference strain rate is set to 0.001. The strain rate set is set to to The temperature sets are set to 100 K, 200 K, 300 K, 400 K and 500 K.

[0057] Step S4: Construction of the defect set. Rectangular cracks and circular holes are both placed at the center of the representative model to reduce boundary interference. Specifically, the short side of the rectangular crack is fixed at 1 nm, and the long side is set to 1 nm, 2 nm, 3 nm, and 4 nm, with the long side of the crack perpendicular to the loading direction; the diameter of the circular hole is set to 1 nm, 2 nm, 3 nm, and 4 nm. Figure 3 A schematic diagram of a typical defect configuration is shown.

[0058] Step S5: Perform bidirectional uniaxial tension. Apply loads along the serrated direction and the armrest direction respectively, while keeping the in-plane stress perpendicular to the loading direction zero. During the tensioning process, the built-in stress and strain calculation module of the molecular dynamics program is invoked to output data in real time, and preferably the results are recorded every 250 time steps to generate stress-strain curves and local atomic stress distribution maps.

[0059] Step S6: Extract mechanical parameters and local stress information. Young's modulus E is obtained through linear fitting of the elastic stage and can be expressed as E = Δσ / Δε; ultimate stress... Take the peak value of the stress-strain curve; ultimate strain The strain corresponding to structural instability or fracture is taken; the toughness U is obtained by integrating the area of ​​the stress-strain curve, and can be expressed as... .

[0060] The von Mises equivalent stress is further calculated for the stress tensor of each atom, and its expression is:

[0061] In the formula, Normal stress acting on a plane whose normal is parallel to the x-axis and whose direction is along the x-axis; Normal stress acting on a plane whose normal is parallel to the y-axis and whose direction is along the y-axis; Normal stress acting on a plane whose normal is parallel to the z-axis and whose direction is along the z-axis; : Shear stress acting on a plane whose normal is parallel to the x-axis and whose direction is along the y-axis.

[0062] : Shear stress acting on a plane whose normal is parallel to the y-axis and whose direction is along the z-axis.

[0063] : Shear stress acting on a plane whose normal is parallel to the z-axis and whose direction is along the x-axis.

[0064] The von Mises equivalent stress can be used to identify high stress concentration areas at the edge of defects.

[0065] Step S7: Perform failure assessment and defect tolerance evaluation. By comparing the global mechanical parameters and the propagation direction of the local high-stress region under different strain rates, temperatures, defect types, and defect sizes, determine the crack initiation location and propagation path.

[0066] Specifically, the atomic clusters at the defect edge where the von Mises stress peak first appears and is accompanied by bond breakage are identified as the crack initiation point; the subsequent high-stress zone propagation direction and the continuous bond breakage sequence are identified as the crack propagation path.

[0067] In strain rate effect analysis, as the strain rate increases from... Increase to DHP-graphene exhibits significant rate-enhancing characteristics. Along the serrated direction, the ultimate stress increases from 56.17 GPa to 61.49 GPa, and the ultimate strain increases from 13.22% to 18.14%; along the armrest direction, the ultimate stress increases from 60.36 GPa to 63.29 GPa, and the ultimate strain increases from 13.95% to 16.10%. In contrast, the Young's modulus only changes slightly, indicating that it is mainly controlled by bond stiffness rather than by the loading rate.

[0068] In the temperature effect analysis, DHP-graphene exhibited significant thermal softening characteristics as the temperature increased from 100 K to 500 K. Along the serrated direction, the ultimate stress decreased from 66.42 GPa to 51.27 GPa, the ultimate strain from 0.2119 to 0.1051, and the toughness from 9.94 GPa to 3.02 GPa; along the armchair direction, the ultimate stress decreased from 67.09 GPa to 49.27 GPa, the ultimate strain from 0.1746 to 0.1007, and the toughness from 7.62 GPa to 2.75 GPa. These results indicate that increasing the temperature enhances atomic thermal vibrations and weakens the effective confinement of C-C bonds, thereby reducing the material's load-bearing capacity and energy absorption capacity.

[0069] In the defect effect analysis, both rectangular cracks and circular pores significantly weaken the strength, ductility, and toughness of DHP-graphene, and the degradation becomes more pronounced as the defect size increases. Taking a rectangular crack as an example, along the serrated direction, when the long side of the crack increases from 1 nm to 4 nm, the ultimate stress decreases from 51.23 GPa to 36.43 GPa, and the ultimate strain decreases from 0.0974 to 0.0600; along the armrest direction, the ultimate stress decreases from 49.52 GPa to 38.54 GPa, and the ultimate strain decreases from 0.0960 to 0.0700.

[0070] Taking a circular hole as an example, along the serrated direction, when the hole diameter increases from 1 nm to 4 nm, the ultimate stress decreases from 51.40 GPa to 40.62 GPa, and the ultimate strain decreases from 0.0985 to 0.0695; along the armrest direction, the ultimate stress decreases from 50.88 GPa to 33.07 GPa, and the ultimate strain decreases from 0.1007 to 0.0565. Combined with the local stress evolution, it can be seen that rectangular cracks are more likely to form tip-dominated directional high stress concentrations, while circular holes tend to form weakened regions that extend circumferentially along the hole boundary.

[0071] In the method provided in this application, the damage difference between rectangular cracks and circular holes depends not only on the defect geometry but also on the matching relationship between the defect boundary curvature and the lattice orientation. Along the serrated direction, longer rectangular cracks have a more significant impact on strength reduction; along the armrest direction, large-sized circular holes have a more significant impact on both strength and ductility reduction. This indicates that the mechanical failure of DHP-graphene is jointly controlled by defect morphology, crystal orientation, and localized stress concentration.

[0072] The molecular dynamics analysis device for the tensile mechanical properties of DHP-graphene provided in this application is described below. The molecular dynamics analysis device for the tensile mechanical properties of DHP-graphene described below can be referred to in correspondence with the molecular dynamics analysis method for the tensile mechanical properties of DHP-graphene described above.

[0073] Figure 4 This is a schematic diagram of the structure of the molecular dynamics analysis device for the tensile mechanical properties of DHP-graphene provided in the embodiments of this application, as shown below. Figure 4 As shown, it includes: a construction module 41, a representative model determination module 42, a setting module 43, a loading module 44, an extraction module 45, and an evaluation module 46, wherein: Module 41 is used to construct and generate multiple defect-free supercell models with different numbers of atoms based on the DHP-graphene monolayer cell model, and to set a vacuum layer in the out-of-plane direction. The representative model determination module 42 is used to perform uniaxial tensile simulations on the multiple defect-free supercell models with different atomic numbers along the serrated direction and the armchair direction under preset temperature and reference strain rate conditions, and determine the representative model size based on the rate of change of ultimate stress, ultimate strain and toughness. The setting module 43 is used to set the molecular dynamics potential function, time step, relaxation condition, loading strain rate set, temperature set and defect set based on the representative model size; the defect set constitutes a defect-containing model. The loading module 44 is used to perform energy minimization and isothermal and isobaric relaxation on the defect-free model and the defective model respectively, and to perform uniaxial tensile loading along the sawtooth direction or armchair direction under isothermal conditions while keeping the in-plane stress perpendicular to the loading direction to zero. Extraction module 45 is used to output stress-strain data and atomic localized stress field in real time during the stretching process, and extract Young's modulus, ultimate stress, ultimate strain and toughness based on the stress-strain data; Output module 46 is used to determine the crack initiation location and propagation path based on the changes in mechanical parameters under different loading strain rates, temperatures, defect types and sizes, as well as the evolution of atomic local stress concentration, and to obtain the anisotropic mechanical response and defect tolerance evaluation results of DHP-graphene.

[0074] Figure 5 An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 5 As shown, the electronic device may include a processor 510, a communications interface 520, a memory 530, and a communications bus 540. The processor 510, communications interface 520, and memory 530 communicate with each other via the communications bus 540. The processor 510 can call logical instructions from the memory 530 to execute the molecular dynamics analysis method for the tensile mechanical properties of DHP-graphene.

[0075] Furthermore, the logical instructions in the aforementioned memory 530 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0076] On the other hand, this application also provides a non-transitory computer-readable storage medium storing a computer program thereon, which, when executed by a processor, is implemented to perform the molecular dynamics analysis method for the tensile mechanical properties of DHP-graphene provided by the methods described above.

[0077] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0078] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A molecular dynamics analysis method for the tensile mechanical properties of DHP-graphene, characterized in that, include: Based on the DHP-graphene monolayer unit cell model, several defect-free supercell models with different numbers of atoms were constructed. Under preset temperature and reference strain rate conditions, uniaxial tensile simulations were performed on the multiple defect-free supercell models with different atomic numbers along the serrated direction and the armchair direction to determine the representative model size; Based on the representative model size, molecular dynamics potential function, time step, relaxation condition, loading strain rate set, temperature set, and defect set are set. Energy minimization and isothermal and isobaric relaxation were performed on the defect-free model and the defective model respectively. Under the condition that the in-plane stress perpendicular to the loading direction is zero, uniaxial tensile loading was applied along the sawtooth direction or the armchair direction under isothermal conditions. During the stretching process, stress-strain data and atomic localized stress fields are output in real time, and Young's modulus, ultimate stress, ultimate strain and toughness are extracted based on the stress-strain data; Based on the changes in mechanical parameters under different loading strain rates, temperatures, defect types and defect sizes, as well as the evolution of atomic local stress concentration, the crack initiation location and propagation path are determined, and the anisotropic mechanical response and defect tolerance evaluation results are obtained.

2. The method according to claim 1, characterized in that, The DHP-graphene monolayer unit cell is composed of five-membered rings, six-membered rings, and ten-membered rings; the defect-free supercell model has a vacuum layer in the out-of-plane direction.

3. The method according to claim 1, characterized in that, The method for determining the representative model size includes: When the rate of change of the ultimate stress, ultimate strain, and toughness of a defect-free supercell model with a certain number of atoms is lower than a threshold, and a balance is achieved between computational accuracy and computational cost, the model with the number of atoms is determined as the representative model size.

4. The method according to claim 1, characterized in that, The set of loading strain rates is as follows: to The temperature range is from 100 K to 500 K, and includes at least 100 K, 200 K, 300 K, 400 K and 500 K.

5. The method according to claim 1, characterized in that, The defect set includes at least rectangular cracks and circular holes; the defect set constitutes a defect-containing model.

6. The method according to claim 1, characterized in that, The Young's modulus is obtained by linear fitting of the elastic stage of the stress-strain curve; the ultimate stress is the peak stress; the ultimate strain is the strain corresponding to structural instability or fracture; and the toughness is the integral area of ​​the stress-strain curve.

7. The method according to claim 1, characterized in that, The location of crack initiation and propagation path were determined by tracking the von Mises stress peak position and bond breakage sequence of the defect edge atoms.

8. A molecular dynamics analysis device for the tensile mechanical properties of DHP-graphene, characterized in that, include: The building block is used to construct multiple defect-free supercell models with different numbers of atoms based on the DHP-graphene monolayer unit cell model. The representative model determination module is used to perform uniaxial tensile simulations along the serrated direction and the armchair direction on the multiple defect-free supercell models with different atomic numbers under preset temperature and reference strain rate conditions to determine the size of the representative model. The configuration module is used to set the molecular dynamics potential function, time step, relaxation condition, loading strain rate set, temperature set, and defect set based on the representative model size; the defect set constitutes a defect-containing model. The loading module is used to perform energy minimization and isothermal and isobaric relaxation on the defect-free model and the defective model respectively. Under the condition that the in-plane stress perpendicular to the loading direction is zero, uniaxial tensile loading is applied along the sawtooth direction or the armchair direction under isothermal conditions. The extraction module is used to output stress-strain data and atomic localized stress field in real time during the stretching process, and extract Young's modulus, ultimate stress, ultimate strain and toughness based on the stress-strain data; The output module is used to determine the crack initiation location and propagation path based on the changes in mechanical parameters under different loading strain rates, temperatures, defect types and defect sizes, as well as the evolution of atomic local stress concentration, and to obtain the anisotropic mechanical response and defect tolerance evaluation results.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the molecular dynamics analysis method for the tensile mechanical properties of DHP-graphene as described in any one of claims 1 to 7.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the molecular dynamics analysis method for the tensile mechanical properties of DHP-graphene as described in any one of claims 1 to 7.

Images