Molecular dynamics simulation method for impact resistance behavior of metal-carbon honeycomb structure

Abstract

The invention discloses a molecular dynamics simulation method for the impact resistance behavior of a metal-carbon honeycomb structure, and relates to the technical field of physical simulation, and the method comprises the steps: constructing a composite structure atom model and an impact projectile rigid body model; performing energy minimization and structural relaxation on the composite structure to obtain a stable initial configuration; the configuration is divided into a fixed constraint area, a temperature buffer area and a free response area along the in-plane direction of a structural plane, and fixed constraint, constant temperature control and micro-regularization system simulation are respectively applied; the composite structure is impacted by a rigid projectile at a preset speed, molecular dynamics impact simulation is carried out under a periodic boundary condition, and atomic motion data are output; by means of the data, structural deformation and damage morphology in the impact process are displayed through visual software, and by extracting a physical information curve, damage evolution and energy dissipation behaviors of a material are quantitatively analyzed, and the atomic scale impact resistance mechanism is revealed. The micro-mechanical behavior simulation of the metal-carbon honeycomb composite structure is realized.

Description

Technical Field

[0001] This invention relates to the field of physical simulation technology, and specifically to a molecular dynamics simulation method for the impact resistance behavior of metal-carbon honeycomb structures. Background Technology

[0002] Carbon-based composite materials, with their lightweight, high specific strength, and excellent energy absorption properties, have shown significant application potential in high-impact protection fields such as aerospace and defense armor. As a typical lightweight porous structure, carbon honeycomb possesses unique advantages in energy absorption; however, pure carbon structures still exhibit high brittleness and limited plastic deformation capacity under extreme impact loads. Therefore, researchers typically employ composite strategies such as metal filling or metal sandwiching to enhance their impact resistance. However, the dynamic response mechanisms of these composite structures at the atomic / nanoscale, such as interfacial behavior, damage evolution, and energy distribution, remain unclear. Traditional experimental methods are difficult to observe microscopic dynamic processes in real time and are costly and time-consuming.

[0003] While molecular dynamics simulations provide an important tool for studying atomic-scale mechanisms, current impact simulations of metal-carbon honeycomb composite systems still have significant shortcomings: a lack of unified and reliable model construction methods, particularly overly simplified interface modeling; arbitrary force field selection and parameter settings affecting the reliability of results; a lack of systematic standards for boundary conditions and temperature control, making results difficult to reproduce; and the absence of a standardized simulation framework applicable to both metal-filled and metal-interlayer composite structures. Therefore, developing a systematic, accurate, and repeatable molecular dynamics simulation method is of great significance for revealing their microscopic mechanisms and guiding material design and optimization. Summary of the Invention

[0004] To better study atomic-scale mechanisms, this invention proposes a molecular dynamics simulation method for the impact resistance behavior of metal-carbon honeycomb structures, comprising the following steps: S1: Construct an atomic model of a composite structure containing a carbon honeycomb matrix and a metallic phase, and construct a rigid atomic model of an impact projectile. S2: Obtain an energy-stable initial configuration by performing energy minimization and structural relaxation on the atomic model of the composite structure; S3: The initial configuration is divided into a fixed constraint region, a temperature buffer region, and a free response region along the in-plane direction of the structural plane. The atoms in the fixed constraint region are in fixed positions during the simulation. The temperature buffer region uses a constant temperature system to control the temperature. The free response region uses a micro-canonical system for dynamic simulation. S4: The rigid body atomic model is impacted by the composite structure atomic model at a preset velocity. Molecular dynamics impact simulation is performed under periodic boundary conditions, and atomic motion data is output. S5: By importing atomic motion data into visualization software, the structural deformation, interface failure and damage morphology during the impact process are displayed. The projectile motion parameters, structural bond breaking information and system energy change data extracted from the atomic motion data are used to quantitatively analyze the damage evolution and energy dissipation behavior.

[0005] The molecular dynamics simulation method provided by this invention establishes a systematic, reliable, and repeatable atomic-scale simulation framework that can accurately reveal the dynamic response, damage evolution, and energy dissipation microscopic mechanism of metal-carbon honeycomb composite structures under high-speed impact, thus providing key theoretical tools and simulation basis for the design and performance optimization of lightweight impact-resistant materials.

[0006] Furthermore, the atomic model of the composite structure is a metal-filled carbon honeycomb composite structure, wherein the metal phase is embedded in the carbon honeycomb matrix in the form of a crystal lattice.

[0007] Furthermore, the atomic model of the composite structure is a metal-carbon honeycomb sandwich composite structure, which includes an upper metal panel, a lower metal panel, and a carbon-based honeycomb core layer located between the two.

[0008] Furthermore, in step S1, the composite atomic model of the carbon honeycomb matrix and the metallic phase is constructed using Materials Studio software, and the rigid atomic model of the impact projectile is generated using the LAMMPS script.

[0009] Furthermore, in step S3, the fixed constraint region is composed of atoms within a region with a thickness of 3 Å at the edge of the composite structure atomic model.

[0010] Furthermore, the molecular dynamics impact simulation in step S4 uses a mixed force field to describe the interatomic interactions; wherein, the interaction between carbon atoms uses the AIREBO potential function, the interaction between metal atoms uses the EAM / FS potential function, and the interface interaction between carbon atoms and metal atoms uses the Lennard-Jones potential function.

[0011] Furthermore, the parameters of the Lennard-Jones potential function are set specifically for the iron-carbon system, wherein the potential well depth... The equilibrium distance is 0.043 eV. 2.221 .

[0012] Furthermore, in step S4, the parameters for the molecular dynamics impact simulation include: periodic boundary conditions, initial temperature, and time step.

[0013] Furthermore, the size of the composite structure atomic model is greater than four times the diameter of the impact projectile.

[0014] Compared with the prior art, the present invention has at least the following beneficial effects: (1) The present invention proposes a molecular dynamics simulation method for the impact resistance behavior of metal-carbon honeycomb structures. By constructing a composite structure atomic model containing a carbon honeycomb matrix and a metal phase, and performing energy minimization and structural relaxation on it, a stable initial configuration is obtained, thus laying the foundation for the accuracy of the simulation. (2) By scientifically dividing the model into a fixed constraint zone, a temperature buffer zone and a free response zone along the in-plane direction of the structural surface, and simulating them with corresponding dynamic systems, the boundary effect was effectively eliminated, and the energy transfer and dissipation behavior during the impact process was realistically reproduced. (3) By extracting and analyzing the projectile motion parameters, structural bond breaking information and system energy changes in atomic motion data, the damage evolution law and energy absorption mechanism of composite materials can be quantitatively revealed at the atomic scale. At the same time, the structural deformation, interface failure and damage morphology can be intuitively displayed with the help of visualization software, realizing the dynamic observation and mechanism verification of the impact process. Attached Figure Description

[0015] Figure 1 This is a step diagram of a molecular dynamics simulation method for the impact resistance behavior of metal-carbon honeycomb structures; Figure 2 A schematic diagram of the atomic structure of a metal-filled carbon honeycomb composite structure; Figure 3 A schematic diagram of a metal-filled carbon honeycomb composite structure for projectile impact; Figure 4 A schematic diagram of a metal-carbon honeycomb sandwich composite structure for projectile impact; Figure 5 A graph showing the change in projectile velocity over time during the impact of a projectile into a metal-filled carbon honeycomb composite structure. Figure 6 The graph shows the change in projectile velocity over time during the impact of a projectile on a metal-carbon honeycomb sandwich composite structure. Figure 7 A diagram showing the process changes when a projectile impacts a target model filled with a carbon honeycomb composite structure in a metal cavity. Figure 8 A diagram showing the process changes when a projectile impacts a target model of a metal-carbon honeycomb sandwich composite structure. Figure 9 Visual comparison of the damage levels of metal-filled carbon honeycomb composite structures under different impact velocities. Detailed Implementation

[0016] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0017] This invention provides a molecular dynamics simulation method for the impact resistance behavior of metal-carbon honeycomb structures. This method, through a systematic and standardized procedure, accurately simulates and reveals the dynamic response, damage evolution, and energy dissipation mechanisms of two promising composite structures—metal-filled carbon honeycomb composites and metal-carbon honeycomb sandwich composites—under high-speed impact loads at the atomic scale. Figure 1 As shown, this molecular dynamics simulation method mainly includes the following steps: S1: Construct an atomic model of a composite structure containing a carbon honeycomb matrix and a metallic phase, and construct a rigid atomic model of an impact projectile. S2: Obtain an energy-stable initial configuration by performing energy minimization and structural relaxation on the atomic model of the composite structure; S3: The initial configuration is divided into a fixed constraint region, a temperature buffer region, and a free response region along the in-plane direction of the structural plane. The atoms in the fixed constraint region are in fixed positions during the simulation. The temperature buffer region uses a constant temperature system to control the temperature. The free response region uses a micro-canonical system for dynamic simulation. S4: The rigid body atomic model is impacted by the composite structure atomic model at a preset velocity. Molecular dynamics impact simulation is performed under periodic boundary conditions, and atomic motion data is output. S5: By importing atomic motion data into visualization software, the structural deformation, interface failure and damage morphology during the impact process are displayed. The projectile motion parameters, structural bond breaking information and system energy change data extracted from the atomic motion data are used to quantitatively analyze the damage evolution and energy dissipation behavior.

[0018] First, the simulation process for the metal-filled carbon honeycomb composite structure is as follows. The initial step of the simulation is to construct an accurate atomic-scale model. Using Materials Studio, a molecular modeling software, the basic unit cell (e.g., based on the crystallographic characteristics of the carbon honeycomb) is constructed. Figure 2 (As shown). This unit cell has specific geometric parameters; for example, in one embodiment, its lattice constant can be set to the lengths of the three edges of the unit cell. The included angle of the three edges This accurately reflects the spatial arrangement of carbon atoms. Subsequently, metal atoms (such as iron atoms) are introduced at specific lattice positions in the carbon honeycomb matrix through atomic substitution or embedding, thus forming an initial configuration where the metal phase and the carbon matrix are composited at the atomic level—that is, a metal-filled carbon honeycomb cell. To obtain a macroscopic model with sufficient size for impact simulation and effective reduction of boundary effects, this cell needs to be periodically expanded in three-dimensional space. For example, through cell expansion, a cell with a size of approximately [missing information] can be obtained. The composite atomic model. The design of this size must meet a basic requirement, that is, the lateral dimensions (length and width) of the model should be significantly larger than the diameter of the subsequent impact projectile. It is usually required that the side length be more than four times the diameter of the projectile, so as to ensure that the impact occurs in the central region of the model and minimize the interference of boundary reflection effects caused by the small size of the model on the dynamics of the core response region.

[0019] While constructing the main model of the composite structure, it is also necessary to construct a model of the impact projectile (such as...). Figure 3 (As shown). In this invention, the projectile is typically simulated as a metallic sphere with a specific crystal structure. For example, the projectile can be constructed using iron atoms with a body-centered cubic (BCC) structure. Using the scripting capabilities of the LAMMPS molecular dynamics software, a spherical assembly of iron atoms with a BCC lattice arrangement can be generated, the diameter of which can be set according to research requirements, for example... After generation, place this projectile model at a certain distance directly above the aforementioned composite structure model to set the initial spatial position for impact simulation. At this point, the complete initial system model, including the target (composite structure) and the projectile, is ready.

[0020] Next, this initial model needs to be preprocessed to eliminate high-energy non-equilibrium states caused by potential overlap, stress concentration, or unreasonable connections at atomic positions during the modeling process. This process is called energy minimization and structural relaxation. Specifically, under a selected interatomic interaction force field, an iterative algorithm is used to reduce the potential energy of the entire system to a minimum or convergent state, thereby adjusting the atomic positions to a more stable configuration. This step is crucial, as it ensures that the simulation starts from a physically reasonable and energy-stable initial state, avoiding artificially introduced numerical instabilities.

[0021] After obtaining the relaxed, stable initial configuration, the composite structure model needs to be partitioned to properly handle boundary conditions and energy dissipation in the simulation. Typically, it is divided into three functionally distinct regions along the in-plane direction (i.e., perpendicular to the model thickness). The outermost layer is the fixed constraint region, which is usually selected from atoms within a certain extension direction of the model's outer edge (e.g., with a thickness of...). The first layer consists of three atomic layers, with their spatial coordinates fixed throughout the simulation. This layer simulates the rigid constraints or supports the material might experience in real-world applications. The middle layer is a temperature buffer zone, simulated using a isothermal system, such as the NVT canonical ensemble, coupled with a Nose-Hoover thermostat for temperature control. This zone absorbs heat and stress waves transmitted from the impact core, preventing non-physical reflections at the fixed boundary that could affect the dynamics of the free response zone, thus more realistically simulating impact propagation in a semi-infinite medium. The innermost layer, directly bearing the impact load, is the free response zone. This zone is simulated using the NVE microcanonical ensemble. Under this ensemble, there is no energy or particle exchange between the system and the outside world; therefore, the motion of atoms in this zone is entirely determined by Newton's laws of motion, realistically reflecting the dynamic evolution of the system under impact loads.

[0022] After completing the region division, the core impact dynamics simulation phase begins. First, using commands in the LAMMPS software (such as the `fix rigid` command), all atoms in the projectile model are set as a rigid body. This means that during the simulation, the relative positions between atoms within the projectile remain unchanged, and the projectile, as a whole, undergoes translation and rotation. This aligns with the high rigidity of high-speed projectiles and significantly reduces computational complexity. Then, global parameters for the entire simulation system are set, including using periodic boundary conditions to simulate the infinite transverse extension of the material, setting the initial system temperature to room temperature (300 K), and determining the time step for the integral motion equations to be 1 femtosecond (1 fs), a timescale suitable for describing atomic vibrations and shock wave propagation. The impact process is initiated by assigning the rigid projectile a specific initial linear and angular velocity (e.g., a linear velocity of 5 km / s and an angular velocity of 0°), causing it to impact the free response region surface of the composite structure model along the normal direction. During the simulation, detailed data on the evolution of the position coordinates, velocities, potential energy, and kinetic energy of all atoms over time are recorded and output.

[0023] After the simulation, the data analysis and results visualization phase begins. The output atomic motion data is imported into professional visualization software, such as Ovito. Using the software's rendering and analysis functions, the process changes of the projectile impacting the target model at different velocities are analyzed, such as... Figure 7 As shown, the damage to the composite structure under different impact velocities is as follows: Figure 9 As shown, this allows for the reproduction of the entire dynamic process of the impact event.

[0024] By generating atomic configuration snapshots at different simulation times (e.g., 0 ps, ​​0.5 ps, 1 ps, 2 ps, 4 ps), the evolution sequence of microscopic damage morphology, including the projectile intrusion process, compressive deformation of the composite structure, buckling and fracture of the honeycomb wall, plastic flow of the metallic phase, and debonding or failure at the interface, can be visually observed. This visualization is indispensable for qualitative understanding of the failure mechanism. Simultaneously, quantitative analysis is performed based on the output data file. By writing scripts or using analysis tools, the instantaneous velocity of the projectile (e.g., [missing data]) can be extracted. Figure 5 As shown, the curves of kinetic energy versus time can be used to analyze the deceleration process and energy transfer efficiency. The changes in total potential energy, kinetic energy, and internal energy of the system can be statistically analyzed, energy evolution curves can be plotted, and the energy absorption capacity of the composite structure can be quantitatively assessed. In particular, by analyzing the changes in interatomic bond lengths, the number of broken covalent bonds (CC bonds) or interfacial bonds (C-metallic bonds) and their spatial distribution over time can be statistically analyzed and plotted, directly revealing the initiation, propagation, and saturation processes of material damage. Combining visual observation with quantitative data allows for a complete and in-depth elucidation of the damage evolution law and energy dissipation mechanism of metal-filled carbon honeycomb composite structures under impact.

[0025] Secondly, for the metal-carbon honeycomb sandwich composite structure, the simulation method maintains a consistent overall framework, but differs in model construction and some details. Modeling of this structure also begins with building separate carbon-based honeycomb core layer models and metal panel models using Materials Studio. The carbon honeycomb core layer can be constructed as a plate-like model with specific dimensions, for example... Metal panels are typically modeled as thin metal layers with a face-centered cubic or body-centered cubic structure, for example, a thickness of... The BCC iron layer has planar dimensions that match the carbon honeycomb core layer. Then, the upper metal panel, carbon honeycomb core layer, and lower metal panel are arranged vertically in sequence, and different interface bonding states are simulated by adjusting the initial spacing between them. In a typical embodiment, to simulate a tight interface bonding, the initial gap between the metal panel and the carbon honeycomb core layer can be set to approximately... Next, similar to the treatment of infill structures, the "sandwich" stacked model is subjected to overall energy minimization and structural relaxation to obtain a stable initial interface bonding configuration. The construction and placement of the impact projectiles are the same as in the aforementioned embodiments.

[0026] The subsequent zoning principles are similar to those described above; this zoning ensures that during the impact process (such as...). Figure 4As shown, the entire path of the load, from the projectile to the upper metal panel, then through the interface to the carbon honeycomb core layer, and finally to the lower metal panel, can be reasonably simulated dynamically. The parameter settings for the impact simulation (e.g., the projectile is a rigid body, periodic boundary, initial temperature of 300K, and a step size of 1fs) remain consistent with the aforementioned settings. In terms of data analysis and visualization, in addition to focusing on the trajectories of all atoms and the projectile velocity (e.g., ... Figure 6 As shown), the change of kinetic energy over time, and the deformation and damage of the overall structure (as shown). Figure 8 As shown in the diagram, special attention should be paid to the behavior of the interface between the upper and lower metal panels and the carbon honeycomb core. Ovito analysis allows for clear observation of whether delamination or slippage occurs at the interface, as well as the reflection and transmission of stress waves at the interface. Quantitative analysis focuses on comparing the attenuation rate of the projectile's kinetic energy, the proportion of energy absorbed by the core and panels, and the impact of interface failure on the overall impact resistance. This reveals the graded impact resistance and energy dissipation synergistic mechanism achieved by this sandwich structure through the plastic deformation of the metal panels, the crushing energy absorption of the core, and the stress redistribution at the interface.

[0027] In summary, this invention proposes a molecular dynamics simulation method for the impact resistance behavior of metal-carbon honeycomb structures. By constructing an atomic model of a composite structure including a carbon honeycomb matrix and a metallic phase, and performing energy minimization and structural relaxation treatments, a stable initial configuration is obtained, thus laying the foundation for simulation accuracy. By scientifically dividing the model along the in-plane direction of the structure into a fixed constraint region, a temperature buffer zone, and a free response region, and simulating each region using corresponding dynamic systems, boundary effects are effectively eliminated, and the energy transfer and dissipation behavior during impact is realistically reproduced. By extracting and analyzing the projectile motion parameters, structural bond breaking information, and system energy changes from the atomic motion data, the damage evolution law and energy absorption mechanism of the composite material can be quantitatively revealed at the atomic scale. Simultaneously, visualization software is used to intuitively display structural deformation, interface failure, and damage morphology, enabling dynamic observation and mechanism verification of the impact process.

[0028] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0029] Furthermore, in this invention, descriptions involving terms such as "first," "second," and "a" are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0030] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0031] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

Claims

1. A molecular dynamics simulation method for the impact resistance behavior of metal-carbon honeycomb structures, characterized in that, Including the following steps: S1: Construct an atomic model of a composite structure containing a carbon honeycomb matrix and a metallic phase, and construct a rigid atomic model of an impact projectile. S2: Obtain an energy-stable initial configuration by performing energy minimization and structural relaxation on the atomic model of the composite structure; S3: The initial configuration is divided into a fixed constraint region, a temperature buffer region, and a free response region along the in-plane direction of the structural plane. The atoms in the fixed constraint region are in fixed positions during the simulation. The temperature buffer region uses a constant temperature system to control the temperature. The free response region uses a micro-canonical system for dynamic simulation. S4: The rigid body atomic model is impacted by the composite structure atomic model at a preset velocity. Molecular dynamics impact simulation is performed under periodic boundary conditions, and atomic motion data is output. S5: By importing atomic motion data into visualization software, the structural deformation, interface failure and damage morphology during the impact process are displayed. The projectile motion parameters, structural bond breaking information and system energy change data extracted from the atomic motion data are used to quantitatively analyze the damage evolution and energy dissipation behavior.

2. The molecular dynamics simulation method for the impact resistance behavior of metal-carbon honeycomb structures as described in claim 1, characterized in that, The atomic model of the composite structure is a metal-filled carbon honeycomb composite structure, wherein the metal phase is embedded in the carbon honeycomb matrix in the form of a crystal lattice.

3. The molecular dynamics simulation method for the impact resistance behavior of metal-carbon honeycomb structures as described in claim 1, characterized in that, The atomic model of the composite structure is a metal-carbon honeycomb sandwich composite structure, which includes an upper metal panel, a lower metal panel, and a carbon-based honeycomb core layer located between the two.

4. The molecular dynamics simulation method for the impact resistance behavior of metal-carbon honeycomb structures as described in claim 1, characterized in that, In step S1, the composite atomic model of the carbon honeycomb matrix and the metallic phase is constructed using Materials Studio software, and the rigid atomic model of the impact projectile is generated using the LAMMPS script.

5. The molecular dynamics simulation method for the impact resistance behavior of metal-carbon honeycomb structures as described in claim 1, characterized in that, In step S3, the fixed constraint region is composed of atoms within a region with a thickness of 3 Å at the edge of the composite structure atomic model.

6. The molecular dynamics simulation method for the impact resistance behavior of metal-carbon honeycomb structures as described in claim 1, characterized in that, The molecular dynamics impact simulation in step S4 uses a mixed force field to describe interatomic interactions; specifically, the AIREBO potential function is used for interactions between carbon atoms, the EAM / FS potential function is used for interactions between metal atoms, and the Lennard-Jones potential function is used for interfacial interactions between carbon atoms and metal atoms.

7. The molecular dynamics simulation method for the impact resistance behavior of metal-carbon honeycomb structures as described in claim 6, characterized in that, The parameters of the Lennard-Jones potential function are set for the iron-carbon system, wherein the potential well depth... The equilibrium distance is 0.043 eV. It is 2.221 Å.

8. The molecular dynamics simulation method for the impact resistance behavior of metal-carbon honeycomb structures as described in claim 1, characterized in that, In step S4, the parameters for the molecular dynamics impact simulation include: periodic boundary conditions, initial temperature, and time step.

9. The molecular dynamics simulation method for the impact resistance behavior of metal-carbon honeycomb structures as described in claim 1, characterized in that, The size of the composite structure atomic model is more than four times the diameter of the impact projectile.

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