69 results about "Energy minimization" patented technology

The invention discloses an optimized molecular dynamics simulation method for a monocrystalline silicon cutting process. Comprising the following steps: initializing and setting parameters, creating a workpiece area, creating an abrasive particle area, creating an atomic box, setting atomic mass, fixing a boundary layer, selecting a potential function, carrying out energy minimization processing and relaxation processing, setting cutting parameters, and carrying out operation simulation and result visualization processing. According to the method, interaction between silicon atoms and interaction between silicon and carbon can be described more accurately by using Tersoft potential; the simulation stability is improved by setting time step length, temperature control and energy minimization; by defining different temperature control layers such as a constant temperature layer and a Newton layer, complex dynamic behaviors in the material cutting process can be better simulated; by optimizing a calculation model and an algorithm, the speed and the precision of atomic motion trail and stress distribution in the process of simulating the cutting of the monocrystalline silicon are remarkably improved, and the stability of the simulation process is ensured.

The invention discloses a molecular dynamics simulation method for CO2-ion oil displacement, and belongs to the technical field of CO2 oil displacement. The method comprises the steps that an oil molecule model, a water molecule model, a CO2 molecule model, a CaCl2 molecule model and a graphene plate model corresponding to target oil reservoir characteristics are established; carrying out geometric structure optimization on each model; the optimized molecular model is assembled into a 'CO2-CaCl2-H2O' ternary displacement system, and molecular dynamics simulation is executed; during simulation, an NVT ensemble is selected, periodic boundary conditions are applied, a COMPASS II force field is adopted, atomic potential parameters are configured, and after operation energy is minimized and temperature is initialized, displacement process simulation is executed; and quantitatively evaluating the oil displacement effect of the displacement medium of the 'CO2-CaCl2-H2O' ternary system on the basis of the trajectory file output by simulation. According to the method, the behavior of molecules under the synergistic effect of multiple displacement media can be better explained, the oil displacement micromechanism under the synergistic effect of the multiple displacement media is embodied, and the method has important significance for optimizing the compact oil reservoir development effect and improving the recovery efficiency.

The invention relates to the technical field of building construction, and provides a high polymer grouting material-concrete interface molecular model construction method which comprises the following steps: constructing an initial PU model, and performing molecular dynamics simulation and full-atom simulation on the model; performing energy minimization and dynamic balance K by adopting an NVT and NPT ensemble; performing crosslinking simulation on the PU model, performing multiple crosslinking cycles at 300K by modifying chemical bonds and adjusting crosslinking degree, and loosening to a stable state under NPT ensemble; constructing a calcium silicate hydrate model, and performing molecular dynamics simulation by using a CSH-FF force field; and combining the PU model with the calcium silicate hydrate model, and performing energy minimization and dynamic balance to complete model construction. Through a molecular dynamics simulation method, the limitation of a traditional experimental technology is broken through, and scientific theoretical support and practical guidance are provided for design of a high polymer grouting material and enhancement of a concrete structure.

The invention relates to the technical field of nanofluid enhanced heat transfer simulation, in particular to a molecular dynamics-based mixed nanofluid heat transfer characteristic analysis method, which comprises the following steps of: constructing a molecular model comprising copper, graphene nanoparticles and an ionic liquid / water mixed base solution, and calculating the heat transfer characteristic of the mixed nanofluid through a distribution potential function and a periodic boundary condition; and performing energy minimization and molecular dynamic relaxation to achieve thermodynamic equilibrium. A steady-state temperature gradient is established based on the unbalanced molecular dynamics principle, and the thermal conductivity is calculated according to the Fourier law. Microcosmic parameters such as a radial distribution function, mean square displacement and the number of hydrogen bonds are synchronously analyzed, and a coupling mechanism of interaction and heat transfer performance of the nano-particle-base fluid interface is disclosed. According to the method, the heat transfer characteristic of the mixed nanofluid can be clarified on the molecular scale, and an efficient and reliable analysis means is provided for nanofluid screening and design in application of a solar heat collector, a heat management system and the like.

The invention discloses an interface thickness parameter acquisition method based on a microcosmic full-atom composite model, and belongs to the field of molecular simulation. The method comprises the following steps of: firstly, constructing a periodic model of a polymer A and a periodic model of a polymer B by utilizing MS software, and after the periodic models are combined, obtaining a global energy minimization total-atom composite model through geometric optimization and dynamic equilibrium optimization; finally, atomic concentration distribution data points of the full-atomic composite model are calculated in an MS software Perl script module through the secondary programming technology, an atomic concentration distribution curve is drawn, and smooth processing is conducted; setting a judgment benchmark of the interface thickness of the full-atom composite model, and judging whether the interface thickness exists in the full-atom composite model or not; and defining an interface thickness calculation formula of the full-atom composite model, and calculating the interface thickness of the full-atom composite model with the interface thickness, so as to quickly, efficiently, accurately and quantitatively calculate the thickness result of the interface layer of the polymer composite material. In addition, the method has the advantages of being convenient to operate and the like.

The invention discloses a method for analyzing the dynamic evolution process of a methane leakage nano-channel in cold spring hydrate, and belongs to the field of natural gas hydrate science and engineering. The method comprises the following steps: constructing a hydrate molecular model and selecting a methane and water molecule force field; a hydrate block and a middle gas channel are arranged in the simulation box, and the gas channel is filled with a methane and water mixture to construct an initial simulation system; performing molecular dynamics simulation on the system under the conditions of energy minimization, pre-balance and different pressures and methane accelerations, and remodeling a gas channel dynamic evolution process in a hydrate growth process; carrying out analysis and three-dimensional rendering on the simulated track, and drawing a three-dimensional morphology graph of the gas channel changing along with time; quantitatively extracting surface area data of the gas channel, and calculating key kinetic parameters, including attenuation rate and half-life period, of the evolution process of the gas channel. According to the invention, the quantitative characterization of the dynamic evolution process of the methane leakage nano-channel in the cold spring environment is systematically realized on the molecular scale for the first time, and the contraction closing behavior of the gas channel under the condition of no methane leakage and the dynamic maintaining or adjusting process of the gas channel under the condition of continuous seepage can be accurately simulated and distinguished; the limitation of a traditional static pore model is overcome, and key basic parameters and method support are provided for revealing the interaction mechanism of methane migration and hydrate growth and constructing a cross-scale seepage model.

The invention provides a micro-scale steady-state meniscus model construction method and device, equipment and a medium, and belongs to the field of micro-scale in-pore flow simulation calculation. According to the method, a micro-scale pore meniscus molecular model containing an upper flat plate, a lower flat plate and a left fixed flat plate is constructed, and liquid is filled in the micro-scale pore meniscus molecular model; the method comprises the following steps: performing energy minimization to obtain a liquid static structure, moving a flat plate to obtain a steady-state structure, performing stress analysis on the steady-state meniscus structure, and counting horizontal tangential force borne by the flat plate under the unit length of a liquid-solid interface within preset time. By constructing the micro-scale pore meniscus molecular model, fluid dynamic behaviors of a three-phase contact line area under the micro-scale can be simulated, data which is difficult to obtain in experiments such as a three-phase interface liquid molecule migration mechanism and the like can be obtained, and the problem that a current experimental method is difficult to reveal a micro-nano liquid-solid interface flow mechanism is solved.

The application relates to a calculation method of a high-temperature alloy impurity diffusion coefficient and an atomic mobility parameter based on a molecular dynamics simulation, which comprises the following steps: parameter setting; model establishment; setting a potential function as a multicomponent EAM alloy potential; energy minimization and setting an initial atomic speed; calculating RDF values of a model system and drawing RDF curves; calculating MSD values of all atoms and respectively outputting MSD values of various atomic groups according to various different metal atom types; defining thermodynamic physical quantity output and commanding each step to output and save; giving a random initial speed to the system, and running under each system in three stages: a temperature rising stage, a temperature keeping stage and continuous temperature keeping and relaxation, and outputting MSD values; calculating the impurity diffusion coefficient of the system based on the MDS values; and taking the measured impurity diffusion coefficient as an input value, and obtaining the atomic mobility parameter through DICTRA software. Compared with the prior art, the application has the advantages of simple method, accurate numerical value and the like.

The invention relates to a three-dimensional modeling method for a reef limestone microstructure, which comprises the following steps of: scanning to obtain an original grayscale image of a rock core sample, and preprocessing the original grayscale image; based on the preprocessed grayscale image, extracting a sample shell mask; establishing a Gaussian mixture model of sample gray level distribution, and determining a segmentation threshold value; classifying and segmenting the volume data through the segmentation threshold to obtain a pore candidate region, a matrix candidate region and a pending region; performing morphological closed operation on the candidate region to obtain a pixel set belonging to the pore and a pixel set belonging to the matrix; and classifying and segmenting the pending region by adopting an energy minimization algorithm based on graph segmentation. According to the method, the GMM dual-threshold segmentation and shell mask construction technology is adopted to accurately extract the core area, and air at the core boundary is prevented from being wrongly segmented into pores, so that the real boundary of the core is completely reserved; according to the method, the pores can be finely judged, the automatic threshold segmentation result is stable and reliable, and manual intervention is greatly reduced.

This invention discloses a method for analyzing the wear of micro-milling tools, relating to the fields of wear mechanism research and molecular dynamics analysis in micro-milling. Specifically, it includes: constructing atomic models of the tool and workpiece, incorporating the geometric features of the cutting edge arc; setting up a simulation environment and dividing the workpiece atoms into boundary layers, isothermal layers, and Newtonian layers; assigning potential functions to the atoms and performing energy minimization and relaxation; constructing a dimensionless scale ratio loading condition based on the equivalent uncut thickness and the cutting edge arc radius; extracting the mechanothermal process quantities and quantitatively characterizing the wear state according to the number of detached atoms, the change in effective cutting edge radius, and interface mixing indices. The aim is to achieve atomic-level quantitative characterization of the wear process of micro-milling tools.

The invention discloses a radionuclide generation and release multi-scale coupling method and system, and the method comprises the steps: building a single crystal cell structure model of a crystal based on the first principle of a material unit cell system according to the determined chemical components and structure of a material, and automatically expanding the single crystal cell structure model into a multi-unit cell structure model; adsorption atoms are introduced into the multi-unit-cell structure model, a convergence test is carried out, and a stable system structure is determined through energy minimization; establishing a diffusion coefficient library of radionuclides in a main material in the reactor based on a stable system structure; calling a multi-physics field coupling program to establish a one-dimensional node model, and searching a diffusion coefficient library according to the one-dimensional node model to complete material parameter setting; and calculating the nuclide concentration distribution of the one-dimensional node model, and obtaining the nuclide release rate within the calculation time according to the concentration difference value before and after calculation. Important input parameters are provided for accurately estimating the release condition of the accumulation amount of the reactor core, isolated and conservative hypotheses are reduced, and the calculation precision is improved.

The application provides a method for predicting the ice inhibition performance of nanometer silicon dioxide based on molecular dynamics simulation. The application comprises the following steps: establishing a functionalized nanometer silicon dioxide model, and establishing an ice-containing water box model according to the size of the functionalized nanometer silicon dioxide model; assembling the nanometer silicon dioxide model and the water box model; selecting a suitable force field for the constructed model and performing energy minimization optimization. Molecular dynamics simulation calculation is performed on the silicon dioxide-ice-water model after energy minimization, and analysis is performed on the model after calculation. The root mean square deviation, root mean square fluctuation and binding energy are analyzed, and the number of hydrogen bonds is counted. Based on the analysis data, the feasibility and effect of the material for inhibiting ice are judged. The application constructs different functionalized materials and evaluates their behavior in the ice-water system, thereby greatly reducing the application cost, saving experimental resources, and guiding the development of a freezing protectant based on nanometer materials.

The invention discloses a molecular aggregation information atomic scale calculation and analysis method for a modified asphalt binder. The method comprises the following steps: generating a modified asphalt binder molecular model of a one-dimensional nano additive phase; performing energy minimization and structural relaxation on the model; calculating a space axis section of the one-dimensional nano additive phase; a corresponding mapping phase axis is obtained in a three-dimensional space according to periodic boundary conditions, and the shortest distance between axis sections is calculated; and calculating the distance between the atoms of different asphalt binder components and the axis section of the one-dimensional nano additive phase to obtain aggregation information of different molecules at the interface. According to the method, molecular modeling, molecular dynamics simulation and molecular aggregation information analysis are integrated, so that the molecular aggregation condition around the one-dimensional nano additive phase in the modified asphalt binder can be effectively analyzed from the atomic scale, and a theoretical basis is provided for regulation and control of physical / chemical characteristics of the modified asphalt binder; and reference is provided for atomic scale analytic calculation of microstructure evolution characteristics.

This invention discloses a method for obtaining interface thickness parameters based on a microscopic all-atom composite model, belonging to the field of molecular simulation. First, using MS software, a periodic model of polymer A and polymer B with local energy minimization is constructed. After combining the two, geometric optimization and kinetic equilibrium optimization are performed to obtain a globally energy-minimized all-atom composite model. Finally, using secondary programming techniques in the Perl script module of MS software, the atomic concentration distribution data points of the all-atom composite model are calculated, the atomic concentration distribution curve is plotted, and smoothing is performed. A criterion for determining the presence of interface thickness in the all-atom composite model is set to determine whether interface thickness exists. A formula for calculating the interface thickness of the all-atom composite model is defined to calculate the interface thickness of the all-atom composite model with interface thickness, thereby quickly, efficiently, accurately, and quantitatively calculating the interface layer thickness of the polymer composite material. Furthermore, this invention also has the advantages of convenient operation.

The application discloses a kind of molecular dynamics simulation methods of gas leakage in metal micro crack, the method is first in supercell iron model pre-set hollow microchannel, obtain the iron model containing micro crack;Energy minimization processing and molecular dynamics simulation are carried out based on periodic gas model, obtain the gas model after relaxation;Vacuum layer, iron model containing micro crack, relaxation gas model, isolation layer splicing are established by micro crack gas leakage interface model, then molecular dynamics simulation is carried out to interface model, according to the leakage rate of gas in micro crack is calculated according to simulation trajectory result.This application method has the advantages of high calculation efficiency, low simulation cost, can construct the complete micro crack gas leakage interface model of nanometer scale, from microcosmic angle of view analyzes the leakage rule and mechanism of gas molecule in micro crack, obtains the internal relation of micro crack size, structure and gas leakage evolution, lays the foundation for the sealing performance, life and reliability of precision instrument promotion.

The invention discloses a method for exploring the influence of electromagnetic waves on a protein structure directly based on molecular dynamics simulation. The method comprises the following steps: acquiring target protein from a protein database; constructing a simulation system; adding a protein force field and a water molecule model; solvent molecules and ions are added to neutralize system charges, and energy minimization treatment is carried out; pre-balancing is carried out under the NVT ensemble and the NPT ensemble; performing molecular dynamics simulation on the simulation system, and storing an atomic coordinate trajectory; and performing post-processing on the track file, extracting distance time sequence data between atoms or residues, screening out atom pairs or residue pairs meeting conditions, performing Fourier transform analysis, and judging whether the possibility of resonance with the electromagnetic wave with the specific frequency exists or not. According to the method, the interaction between the protein and the electromagnetic field can be revealed under the atomic resolution without consumption of experimental materials, and an efficient and reliable molecular-level theoretical basis is provided for evaluating the biological effect of environmental electromagnetic radiation.

The application discloses a kind of calculation methods for determining C-S-H pore structure in irreversible shrinkage range, comprising the following steps: establishing C-S-H pore structure model;Using Helmholtz free energy to describe the energy of C-S-H pore structure model;Establish the relationship between the energy part related to physical entropy and pore structure;Establish the relationship between the energy part related to total volume and pore structure;Establish the relationship between the energy part related to surface energy and pore structure;Determine the calculation parameter, and carry out energy calculation to C-S-H pore structure model in given calculation range;Determine the effective C-S-H pore structure energy calculation range;Based on the principle of energy minimization, determine the structure information and structure parameters corresponding to stable C-S-H pore structure model.The application solves the problem that various experimental measurement methods and structure models in the prior art are qualitatively described in the structure characterization of C-S-H pore structure under different humidity, without quantitatively describing C-S-H pore structure information.

The present invention discloses a conformal periodic flattening method for a surface with genus, and relates to the field of surface flattening. The steps are as follows: for an input triangular mesh surface, first check the genus number of the surface. If the genus number is greater than 1, cut the surface into multiple sub-surfaces with genus 1, otherwise record the original surface as a sub-surface; secondly, search for the ring handle ring and tunnel ring of each sub-surface and cut them; then establish a periodic condition for the ring slit boundary inside each sub-surface, establish a flipping condition for the slit boundary between two sub-surfaces, construct a coupled conformal energy minimization model and solve it, obtain the vertex mapping coordinates, periodic translation and flip center; finally, construct a conformal periodic flattened mesh for each sub-surface according to the results. The method of the present invention constructs a periodic condition and flipping condition based on the slit, calculates the conformal periodic flattening mapping by conformal energy minimization, ensures the high conformality of the mapping at the slit, and is applicable to any surface with genus.

The invention provides a method for calculating the influence of rubber compatibility on mechanical properties by using dissipative particle dynamics. The method comprises the following steps: constructing a full-atom model of a to-be-calculated rubber molecular structure unit and performing energy minimization calculation; calculating solubility parameters of each unit structure by using a molecular dynamics method; carrying out coarse graining on the unit structures and calculating conservative repulsive force parameters among different particles; constructing a dissipative particle model of a to-be-calculated rubber system, wherein particles are connected through spring keys; constructing an input file to execute dissipative particle dynamics calculation, and calculating the compatibility among different rubber components; and introducing an entanglement point structure into the dissipative particle model to calculate the mechanical property in the uniaxial tensile mode. The method provides an efficient and reliable molecular simulation method for researching the influence of the rubber compatibility on the mechanical property of a composite system, effectively saves the test cost, and is suitable for solving the technical problem that the mechanical property of a rubber material is poor due to uneven dispersion of rubber.

This invention belongs to the field of seismic data processing and relates to a method and system for consistent processing and adaptive fusion of seismic attributes in multiple contiguous seismic work areas. The method includes: S1: dividing the spatial coordinates of the original seismic attribute data into a grid and establishing a gridded data index; then, based on the gridded data index, executing a localized search strategy to extract the neighboring data point set of the seismic data points to be processed; S2: eliminating systematic value range differences in the original seismic attribute data based on the neighboring data point set and stitching them together to obtain consistent fused seismic attribute data; S3: using a hierarchical interpolation strategy to fill in blank areas to obtain continuous seismic attribute interpolation data; and S4: performing global optimization based on Gaussian pyramid decomposition and an energy minimization model to obtain the final fused seismic attribute data. This method achieves better work area stitching and interpolation, efficiently avoiding the attribute non-fusion effect of traditional work area stitching methods, thereby realizing the goal of consistent seismic attribute stitching across multiple work areas.

The present invention relates to the field of micro-nanomaterial technology, and specifically to a method for modeling interstitial atom segregation grain boundaries for molecular dynamics simulation, comprising: establishing a unit cell with completely filled interstitials; constructing an initial grain boundary model; determining an interstitial atom distribution density function; segmenting the initial grain boundary model into segments and determining the proportion of interstitial atoms within each segment; deleting excess interstitial atoms to obtain a target grain boundary model that meets segregation distribution requirements; and energy minimizing the target grain boundary model to obtain a final grain boundary model with different degrees of segregation. By introducing an interstitial atom distribution density function, the present invention can flexibly control the distribution of interstitial atoms in the grain boundary model, thereby enabling subsequent molecular dynamics simulations to target interstitial solid solution systems under different segregation conditions, and achieving modeling of arbitrary grain boundary models containing interstitial solutes, thereby enabling subsequent molecular dynamics simulations to target different grain boundary models.

The invention discloses a crack global optimization reconstruction method and system for structure detection. The method comprises the following steps: preprocessing a structure surface image, detecting cracks, and analyzing a connected region to obtain a discrete crack fragment set; extracting geometrical characteristics of each fragment, and calculating a fragment pair space adjacent distance to construct a candidate connection set and a crack connection graph; constructing a feature vector based on the connection probability features, and combining a likelihood model and a structure prior model to form a probability graph model; and after the problem is converted into an energy minimization problem, performing iterative optimization through a maximum posterior probability inference algorithm dynamically updated by a structural state, screening an optimal connection relation set, and combining crack segments to realize global optimization reconstruction. According to the invention, the accuracy and continuity of crack detection in a complex scene can be improved.

This invention discloses a material force field fitting method based on potential energy surface matching, comprising: S1 obtaining the corresponding chemical structural formula of the target material; S2 constructing a chemical structural model of the connecting bonds in the chemical structural formula based on the atomic hybridization state of the chemical structural formula; S3 performing preliminary structural optimization on the chemical structural model to obtain the energy-minimizing structure; S4 calculating the chemical structural parameters of the target material using the DFT method based on the energy-minimizing structure; S5 obtaining the Morse bond stretching potential parameter using the Morse algorithm based on the chemical structural parameters and saving it in the molecular simulation file; S6 repeating S2-S5 until the calculation of all chemical structural models is completed, and integrating all molecular simulation files into the force field file; S7 performing molecular simulation based on the force field file obtained in S6 to calculate the mechanical properties of the target material. This method, by introducing the Morse bond stretching potential parameter, makes the simulation results of fiber materials more consistent with reality.

The invention relates to the technical field of heat insulation processes, and discloses a molecular dynamics optimization process for regulating and controlling a microporous structure of an aerogel layer, which comprises the following steps of: constructing an initial atomic model of aerogel molecules and generating a corresponding force field parameter file on the basis of a multi-software cooperative workflow; based on the three-dimensional space size of the initial atomic model, a space index data structure is initialized, and the data structure is used for efficiently storing and querying atomic space position information; and performing energy minimization calculation on the initial atomic model to obtain an initial equilibrium system. According to the method, an automatic modeling process is constructed by integrating multiple software, the calculation efficiency is greatly improved by adopting a spatial index and dynamic updating mechanism based on a hash table, super-large-scale system simulation is supported, and meanwhile, an intelligent optimization engine is introduced to automatically optimize simulation parameters; the problems of flow splitting, limited calculation scale and dependence on manual trial and error parameter adjustment in the prior art are effectively solved.

The invention discloses a molecular dynamics simulation method for solution strengthening and grain boundary strengthening of molybdenum-regulated nickel-based superalloy, and belongs to the technical field of computational material science and molecular dynamics simulation. The method comprises the following steps: constructing a solid solution strengthening model and a grain boundary strengthening model; a multi-element MEAM alloy potential is adopted; performing energy minimization processing; performing balancing; performing stretching simulation; and carrying out data calculation on the solid solution strengthening model and the grain boundary strengthening model, drawing a performance diagram, and analyzing the solid solution strengthening and grain boundary strengthening effects of the molybdenum-regulated nickel-based superalloy. According to the method, the influence of different Mo contents on solution strengthening and grain boundary strengthening of the NiCoMo alloy in dislocation evolution, stress distribution, phase change behavior and the like is obtained through molecular dynamics simulation, so that the key effect of the Mo element in improving the mechanical property of the material is disclosed from the atomic scale, and theoretical support is provided for design and optimization of the NiCoMo alloy.

The application discloses a kind of focusing topography recovery methods based on k near neighbor optimization and alternate direction multiplier, comprising: collecting multi-focus image sequence, using improved MLAP operator to evaluate focusing degree and probability fusion to generate full-focus image;Based on the feature space of full-focus image, k nearest neighbor search is performed, and non-local weighted optimization is carried out on focusing volume;Initial depth map is obtained by three-point Gaussian interpolation;The reliability of focusing curve is calculated, and the data fidelity weight is calculated differentially, and the smooth guiding weight is calculated in combination with the color gradient of full-focus image;An energy minimization model is constructed, and the constraint optimization problem of the model is decomposed into iterative solution of depth map sub-problem, auxiliary variable sub-problem and dual variable sub-problem by using alternate direction multiplier method, and the initial depth image is optimized to obtain the final depth image.The application can effectively solve the depth distortion and edge blur problem in weak texture area, and has excellent topography recovery performance and solving efficiency under weak texture and high noise conditions.

The invention discloses a method for predicting the diffusion behavior of underground hydrogen in the pore scale of water-containing clay minerals and application, and belongs to the technical field of underground hydrogen energy storage and unconventional gas migration prediction. Performing energy minimization and pre-balance on the initial pore model of the water-containing clay mineral through a molecular dynamics method; filling hydrogen molecules under given temperature and pressure conditions through a giant regular Monte Carlo method, and correcting the hydrogen pressure through an SRK-EOS state equation; according to the method, the temperature and the fugacity are used as input parameters, hydrogen diffusion simulation is carried out through a molecular dynamics method, the mean square displacement of hydrogen in the pores is calculated, and the self-diffusion coefficient is obtained, and the diffusion rate change rule of the hydrogen in the clay pores under the conditions of different water film thicknesses, salinity and temperature pressure can be quantitatively represented; diffusion inflection points, diffusion suppression stages and migration limitation mechanisms caused by water film or water bridge structures are disclosed.

The invention discloses a method for calculating a capillary liquid bridge effect between particles based on an energy minimization principle, and relates to the technical field of wet particle system microcosmic acting force calculation. The method comprises the following steps: firstly, establishing a physical geometric model containing upper and lower spherical particles and a three-phase contact line, and calculating the total free energy of a system; then establishing volume conservation and contact angle constraint conditions, and solving a stable liquid bridge form which minimizes total free energy through iterative optimization algorithms such as gradient descent; and then capillary liquid bridge force is calculated based on the change of system energy along with the particle spacing in the stable form, and the liquid bridge fracture distance is determined by gradually increasing the spacing until a stable solution cannot be obtained. The method breaks through the idealized assumption of a traditional method on the shape and the contact angle of a liquid bridge, can accurately process the complex conditions of asymmetric and large-volume liquid bridges and the like, and provides accurate capillary force input parameters for discrete element simulation of a wet particle system.

The invention discloses a method for simulating the impact resistance behavior of a graphene-coated nanocrystalline metal composite structure based on molecular dynamics. The method is characterized by comprising the following steps: firstly, generating a nanocrystalline metal matrix model by adopting Atomsk software; then, LAMMPS software is used for constructing a target body composite model of the graphene coated nanocrystalline metal; performing energy minimization processing and relaxation operation on the target body composite model in sequence, adding a rigid projectile body into the target body composite model, constructing a complete impact simulation model, monitoring and recording motion parameters of the rigid projectile body in real time by LAMMPS software in the impact simulation process, and calculating the motion parameters of the rigid projectile body according to the motion parameters of the rigid projectile body. Visually analyzing the deformation, damage and failure evolution process of the target body composite model under the high-speed impact load through visual software; the method has the advantages that the anti-impact behavior and the damage failure mechanism of the graphene-coated nanocrystalline metal composite structure are accurately revealed from the micro-level of molecular atoms, the application range is wide, the method can adapt to different types of metal matrixes such as copper, iron and magnesium, and the anti-impact behaviors under different working conditions can be simulated by adjusting simulation parameters.

The present invention discloses a method for quantitatively characterizing the anti-adhesion effect of a hydrophilic polymer brush coating, comprising the following steps: constructing a polymer brush coating model; setting the polymer brush coating model, and the set parameters include the boundary conditions of the calculation system, environmental temperature, selection of potential function, energy minimization, relaxation equilibrium, and output parameters; using the MD method to simulate and calculate the movement and distribution of atoms in the system based on classical Newtonian mechanics, recording the position and velocity information of each atom at each simulation moment until obtaining the atomic trajectory information of long-time simulation; according to the calculated atomic velocity and position information, analyzing and obtaining the thermodynamic parameters of the target system, including the repulsive force of the polymer brush coating against protein adhesion, the interaction between the polymer brush coating and the protein, and the deformation degree of the protein on the surface of the polymer brush coating. It solves the problem that it is difficult to quantitatively characterize the anti-protein adhesion effect on the surface of a hydrophilic polymer brush coating in the existing molecular dynamics simulation technology.