A damage effect assessment system based on large model

Abstract

The invention discloses a damage effect assessment system and method based on a large model, and relates to the technical field of nuclear explosion damage. The invention generates a computational grid adapted to different complexities based on an adaptive grid technology, determines a computational domain and refines the grid in a complex terrain area by importing a high-precision three-dimensional terrain model, and improves local simulation accuracy; at the same time, a coarser grid is used in a simpler area, which saves computational resources and significantly improves the fineness of the model and the accuracy of the simulation; through multi-scale coupling and multi-physical field coupling technology, a macro-scale CFD simulation is combined with a micro-scale DEM simulation, and thermal effect, radiation effect and structural mechanics coupling simulation are introduced; the shock wave, heat conduction, radiation propagation and their comprehensive influence on buildings and terrain are comprehensively analyzed; the comprehensiveness and accuracy of the assessment are improved, and the assessment result has more practical significance.

Description

Technical Field

[0001] The present invention relates to the field of nuclear explosion damage technology, and in particular to a damage effect assessment system based on a large model. Background Art

[0002] The killing and destructive effect of nuclear weapons refers to the killing and destructive effects and effects caused by nuclear weapon explosions on personnel and objects, also known as the damage effect; usually, when an atomic bomb explodes in the air, the shock wave accounts for about 50% of the total energy, light radiation accounts for about 35%, early nuclear radiation accounts for about 5%, and radioactive contamination accounts for about 10%; when a hydrogen bomb explodes in the air, the total share of shock waves and light radiation increases, while the share of radioactive contamination decreases, and the increase or decrease varies with the fusion-fission ratio.

[0003] The assessment of the destructive effects of a nuclear explosion is crucial in military and emergency response. Complex terrain (such as high-rise building dense areas in cities, mountains, etc.) has a great influence on the propagation path and intensity of shock waves, and traditional methods are difficult to accurately assess these effects. Accurately assessing the comprehensive impact of a nuclear explosion on buildings, terrain and the environment is crucial for formulating emergency response and rescue plans.

[0004] At present, empirical formulas and simplified models are usually used to estimate the propagation of shock waves and their damage effects in response to the above problems. It is assumed that the terrain is flat or there are only simple obstacles. This method lacks accuracy when facing complex terrain and cannot be effectively evaluated. In addition, the current single physical field simulation mainly focuses on the propagation of shock waves, ignoring the combined influence of thermal effects, radiation effects and structural mechanics physical fields. The evaluation results are not comprehensive, and cannot reflect the secondary effects of building collapse and terrain changes on shock wave propagation after the explosion in real time. There is a lack of dynamic update mechanism. Therefore, there is an urgent need for a damage effect assessment system based on a large model to solve such problems. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a damage effect assessment system based on a large model to solve the problems existing in the prior art, such as lack of accuracy and inability to effectively assess complex terrains; single physical field simulation mainly focuses on the propagation of shock waves, ignoring the combined influence of thermal effects, radiation effects and structural mechanics physical fields, and the assessment results are incomplete, and cannot reflect in real time the secondary effects of building collapse and terrain changes on shock wave propagation after the explosion, and lack of a dynamic update mechanism.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0007] The present invention provides a damage effect assessment system based on a large model, including a data acquisition module, an explosion terrain simulation module, a numerical simulation module and a multi-physical field coupling simulation module:

[0008] The data acquisition module performs LIDAR scanning and remote sensing data acquisition to obtain point cloud data and image data of the target area;

[0009] Explosion terrain simulation module, used to determine the explosion point and its initial conditions, generate the initial mesh, and simulate the behavior of materials under the action of shock waves;

[0010] Numerical simulation module, used to simulate shock wave propagation, simulate material damage, and multi-scale coupling;

[0011] The multi-physics coupling simulation module is used to simulate the coupling effects of fluid mechanics and heat conduction, the coupling effects of radiation transmission and fluid mechanics, heat conduction, and the coupling effects of structural mechanics, heat conduction, and fluid mechanics.

[0012] The present invention also provides a large-model-based damage effect assessment system, which uses the large-model-based damage effect assessment system described above and includes the following steps:

[0013] Step 1. Data collection and preprocessing: Use LIDAR and remote sensing technology to obtain high-resolution terrain data of the target area; use GIS system to process data and generate a three-dimensional terrain model; in addition, collect microstructure and mechanical property data of relevant materials to provide a data basis for microscale simulation;

[0014] Step 2. Model construction and grid generation: construct the computational domain according to the terrain model, and generate computational grids of different complexity based on adaptive grid technology; determine the explosion point and its initial conditions, including the explosion equivalent and the explosion center height; construct the microstructure model of the material, and use the discrete element method to simulate the behavior of the material under the action of the shock wave;

[0015] Step 3. Numerical simulation and multi-scale coupling. On a macro scale, the CFD algorithm is used to perform numerical simulation of the propagation of explosion shock waves, and the propagation path, intensity attenuation and secondary reflection effect of shock waves under complex terrain conditions are analyzed; on a micro scale, the microstructural changes and damage mechanisms of materials under the action of shock waves are simulated; CFXDEM and FluentDEM software are selected for multi-scale coupling, and the micro-simulation results are fed back to the macro model. The parameters of the macro model are dynamically adjusted through adaptive grid technology to improve the simulation accuracy;

[0016] Step 4. Multi-physics coupling simulation, introducing thermal effect, radiation effect and structural mechanics coupling simulation, comprehensively evaluates the comprehensive damage effect of nuclear explosion on different materials and structures; uses multi-physics coupling algorithm to comprehensively analyze shock waves, heat conduction, radiation propagation and their comprehensive impact on buildings and terrain;

[0017] In step 4, thermal effect, radiation effect and structural mechanics coupling simulation are introduced:

[0018] Select ANSYS Multiphysics, COMSOL Multiphysics, and Abaqus multi-physics field coupling simulation platforms, and import the multi-scale coupling simulation results of step 3 as initial conditions and boundary conditions;

[0019] Establish corresponding mathematical and physical models for each physical field, including fluid mechanics, heat conduction, radiation transfer, and structural mechanics;

[0020] Define the coupling relationship between different physical fields in the simulation platform, including thermal-structural coupling and fluid-structural coupling;

[0021] Set the interaction parameters between physical fields, including thermal conductivity, radiation absorption coefficient, and material thermal expansion coefficient;

[0022] Establish a thermal effect model produced by a nuclear explosion, simulate the impact of high temperature on surrounding materials and structures, define thermal conduction boundary conditions, including radiation heat source, convection heat transfer, and heat conduction, run thermal conduction simulation, and analyze high-temperature heat conduction processes and temperature distribution;

[0023] Establish a radiation transmission model to simulate the electromagnetic radiation and optical radiation effects produced by a nuclear explosion;

[0024] Establish a structural mechanics model to simulate the destructive effects of nuclear explosion shock waves and thermal effects on buildings and terrain;

[0025] Run multi-physics coupled simulations to comprehensively analyze shock waves, heat conduction, radiation propagation and their combined effects on buildings and terrain;

[0026] The present invention is further configured that the data collection and preprocessing step in step 1 includes:

[0027] According to the size and terrain characteristics of the target area, corresponding LIDAR equipment and remote sensing technology, including UAV LIDAR, airborne LIDAR, and satellite remote sensing, are used to formulate flight paths, scanning frequencies, and altitude parameters to cover the target area;

[0028] Perform LIDAR scanning and remote sensing data collection to obtain point cloud data and image data of the target area;

[0029] Perform preliminary data processing, including denoising, filtering, and point cloud classification to separate ground points from non-ground points;

[0030] Fuse and integrate multi-source data, including LIDAR point cloud, remote sensing images, and geographic information, to generate a unified terrain dataset;

[0031] The triangulated mesh algorithm TIN and the grid DEM interpolation algorithm are used to generate the terrain surface model;

[0032] In step 1, the microstructure and mechanical properties data of relevant materials are collected simultaneously:

[0033] Includes the types of major building and geological materials in the target area, i.e., concrete, steel, soil;

[0034] Material microstructure and mechanical property data, including elastic modulus, density, and fracture toughness;

[0035] The present invention is further configured such that the method of constructing the calculation domain according to the terrain model in step 2 is:

[0036] Import the 3D terrain model generated in step 1 into the 3D simulation platform, and determine the spatial range of the calculation domain according to the terrain characteristics and the impact range of the nuclear explosion. The calculation domain includes the explosion center and the surrounding area, and covers all important paths and reflection areas of shock wave propagation.

[0037] Divide the computational domain into multiple sub-areas, and make detailed divisions in complex terrain areas, such as densely built-up areas and mountainous areas;

[0038] Then, computational grids that adapt to different complexities are generated, and the resolution and density of the initial grid are set according to the actual terrain complexity and simulation accuracy;

[0039] Generate the initial grid in the computational domain and optimize it using adaptive grid technology;

[0040] Use finer grids in complex terrain and key areas, i.e. around buildings and where terrain changes suddenly, to improve local simulation accuracy; use coarser grids in other areas to save computing resources;

[0041] The present invention is further configured such that the explosion point and its initial condition are determined in step 2 in the following manner:

[0042] Determine and mark the epicenter of a nuclear explosion based on actual conditions or hypothetical scenarios;

[0043] Set the explosion equivalent and explosion center height, and set the initial conditions of the explosion, including the explosion energy release rate, initial shock wave pressure and velocity distribution;

[0044] Input the explosion point location and initial conditions into the three-dimensional simulation platform;

[0045] Then the microstructure model of the material is constructed, and the discrete element method DEM is used to simulate the microstructure of the material;

[0046] Define the geometry, size, and interaction forces of particles or cells in the microstructural model;

[0047] Simulate the behavior of materials under shock waves at a microscopic scale and analyze the displacement, deformation and failure mechanism of particles or units;

[0048] Output simulation results;

[0049] Step 2: Construct a refined computational domain and grid model to simulate the propagation path and intensity attenuation of nuclear explosion shock waves under complex terrain conditions; at the same time, use the discrete element method to simulate the microstructure of the material and provide material behavior data;

[0050] The present invention is further configured that a method for generating a computational grid adapted to different complexities based on the adaptive grid technology includes:

[0051] According to the terrain complexity and simulation accuracy requirements, the resolution Δx0 and density ρ0 of the initial grid are set;

[0052] Select tetrahedral mesh and hexahedral mesh to generate the initial mesh Ω0 in the computational domain;

[0053] Calculate the error estimate E in the initial grid i , the mesh refinement or coarsening is determined by estimating the error of the local solution;

[0054] Using gradient-based error estimation: E i =|▽·(φ h -φ ref )|, where φ h is the solution for the current grid, φ ref is the reference solution (high-resolution solution), ▽ represents the gradient operator;

[0055] According to the error estimate E i Identify the mesh cells that need to be refined or coarsened:

[0056] Refinement strategy: Refine the mesh in high error areas. The refinement factor γ is defined as: Δx i+1 =Δx i / γ,γ>1;

[0057] Coarsening strategy: Coarsening the grid in low error areas, the coarsening factor β is defined as: Δx i+1 =Δx i ×β,β<1; here Δx i Indicates the size of the current grid cell, Δx i+1 It represents the size of the grid unit after the next grid refinement or coarsening, that is, the grid resolution of the i+1th step;

[0058] The mesh resolution is adjusted by an adaptive mesh generation algorithm, which uses a variational principle-based approach to generate an adaptive mesh by minimizing an error functional: Where λ is the regularization parameter used to balance the variation of error and mesh size, and Ω is the computational domain;

[0059] Regenerate the mesh and adjust the mesh element size according to the refinement and coarsening rules;

[0060] The present invention is further configured such that the numerical simulation on a macroscopic scale comprises:

[0061] Select ANSYS Fluent and OpenFOAM fluid mechanics CFD software, and import the calculation domain and adaptive mesh model generated in step 2;

[0062] According to the explosion point and its initial conditions, the boundary conditions and initial conditions of the CFD model are set;

[0063] Define the boundary type of the computational domain, including solid boundary and open boundary; and fluid properties, including air density and viscosity;

[0064] Use the explosion energy release model to simulate the initial energy release and shock wave generation of a nuclear explosion, and set the parameters of the explosion source, including the energy release rate and initial pressure distribution;

[0065] Run CFD simulations to calculate the propagation path, intensity attenuation and secondary reflection effects of shock waves in complex terrain conditions;

[0066] Analyze CFD simulation results and extract shock wave propagation path, pressure distribution, and velocity field data;

[0067] Simulations at the microscopic scale include:

[0068] Select LAMMPS and EDEM discrete element method simulation software and import the material microstructure model constructed in step 2;

[0069] According to the collected material property data, the material properties of particles or units in the microstructure model are set;

[0070] Define the interaction force model between particles or units, including contact force, friction force, and adhesion force;

[0071] The shock wave pressure distribution data obtained from the macro-scale CFD simulation is used as load input and applied to the microstructure model;

[0072] Simulate the behavior of materials under shock waves and analyze the displacement, deformation and failure mechanism of particles or units;

[0073] Analyze DEM simulation results and extract the damage mode and microstructure change data of materials under the action of shock waves;

[0074] The present invention is further configured such that the multi-scale coupling mode is:

[0075] Feedback the material failure data and stress-strain relationships obtained from micro-scale simulations to the macro CFD model;

[0076] Update material properties and failure model parameters in the macro model to reflect changes in the microstructure;

[0077] Adaptive mesh technology is used to dynamically adjust the mesh resolution of the macro CFD model based on the data fed back from the micro simulation.

[0078] Improve the grid resolution in key areas, i.e., material damage areas and shock wave reflection areas, to improve calculation accuracy;

[0079] Run multi-scale coupled simulations, combining the results of macro CFD and micro DEM for joint calculations;

[0080] Analyze the interaction of multiple physical fields in coupled simulations and comprehensively evaluate the combined impact of shock waves, thermal effects, and radiation effects;

[0081] This achieves multi-scale coupling of CFD simulation at the macro scale and DEM simulation at the micro scale; uses multi-scale coupling simulation technology to more accurately predict the propagation of explosion shock waves and their damage effects under complex terrain conditions, improving the accuracy and reliability of assessment results; and provides more comprehensive and dynamic damage assessment results through adaptive grid technology and multi-physics field coupling simulation.

[0082] The present invention is further configured that the CFD explosion shock wave propagation numerical simulation method on a macro scale is:

[0083] Import the adaptive grid and terrain model generated in step 2 into the simulation environment, set the explosion point location and initial explosion parameters, set the explosion equivalent to Q, the initial pressure to P0 and the density to ρ0;

[0084] The explosion energy release is expressed as: Where E is the total energy density, u is the initial velocity, and γ represents the specific heat ratio;

[0085] Set fluid boundary conditions and solid boundary conditions for terrain and buildings;

[0086] Perform CFD simulation, solve the fluid equations, and use the Navier-Stokes equations to describe fluid motion: Among them, θ is the partial derivative, u represents the velocity field, τ is the stress tensor, g is the gravitational acceleration, ▽ is the gradient operator, ρuu represents the tensor product of density ρ multiplied by the velocity field u, describing the convection term of the momentum flow, PΙ represents the pressure P multiplied by the unit tensor Ι, representing the static pressure term of the fluid, ▽·τ+ρg represents the divergence term of the stress tensor τ plus the density ρ multiplied by the gravitational acceleration g, describing the effect of external forces and gravity on the fluid;

[0087] Compute the pressure wave advance and decay using the blast wave propagation model: Among them, r represents the distance from the explosion center to the observation point, r0 is the initial distance, α and β are empirical parameters, and t is the explosion time from the explosion center to the observation point;

[0088] Coupled kinetic and energy equations: Where E is the total energy density and Q is the heat source term;

[0089] Extract and analyze shock wave propagation path, pressure distribution, and velocity field data;

[0090] The present invention is further configured such that the simulation method of the microscopic structure change and the damage mechanism of the DEM at the microscopic scale is:

[0091] Import the constructed material microstructure model to define the geometry and density of particles or units p , elastic modulus E p , fracture toughness K p ;

[0092] Define the interaction force model between particles, including the contact force F c , friction force F f Adhesion force F a ;

[0093] Set the initial position and velocity of the particles and apply shock wave load based on CFD simulation results;

[0094] Perform a DEM simulation and use Newton's second law to solve the particle motion equation: Among them, m i is the particle mass, r i is the particle position, i represents the index of the current particle, j represents the index of other particles that interact with particle i, and F c,ij 、F f,ij 、F a,ij represents friction, adhesion, and fracture;

[0095] Simulate the breaking of interparticle bonds using a fracture mechanics model: Among them, F b is the breaking force, K bis the fracture stiffness coefficient, Δl is the displacement change, l0 is the initial length, and α is the material constant;

[0096] Thermal conduction and mechanical coupling effect: Q ij =-k▽T ij , where Q ij is the heat flow, k is the thermal conductivity, ▽T ij is the temperature gradient;

[0097] Extract the displacement, deformation and fracture data of particles and analyze the damage mechanism of materials under the action of shock waves;

[0098] Generate detailed reports including particle motion, deformation and damage, and output data for multi-scale coupling;

[0099] Combine the simulation methods at the micro and macro scales to refine the shock wave propagation characteristics and physical mechanisms at different scales. Use multi-scale simulation technology to refine the simulation at the micro and macro scales to improve the accuracy of the shock wave propagation characteristics.

[0100] Compared with the prior art, the present invention has the following beneficial effects:

[0101] The present invention generates computational grids that adapt to different complexities based on adaptive grid technology, imports a high-precision three-dimensional terrain model, determines the computational domain, and refines the grids in complex terrain areas to improve local simulation accuracy; at the same time, coarser grids are used in simpler areas to save computing resources, significantly improving the model's refinement and simulation accuracy;

[0102] The present invention combines macro-scale CFD simulation with micro-scale DEM simulation through multi-scale coupling and multi-physics field coupling technology, and introduces thermal effect, radiation effect and structural mechanics coupling simulation; comprehensively analyzes shock waves, heat conduction, radiation propagation and their comprehensive impact on buildings and terrain; improves the comprehensiveness and accuracy of the assessment, making the assessment results more realistic;

[0103] It solves the problems existing in the prior art, such as lack of accuracy and inability to effectively evaluate when facing complex terrain; single physical field simulation mainly focuses on the propagation of shock waves, ignores the combined influence of thermal effects, radiation effects and structural mechanics physical fields, and the evaluation results are incomplete, and cannot reflect in real time the secondary effects of building collapse and terrain changes on shock wave propagation after the explosion, and lacks a dynamic update mechanism. BRIEF DESCRIPTION OF THE DRAWINGS

[0104] Figure 1 This is a framework diagram of the damage effect assessment system based on a large model of the present invention. DETAILED DESCRIPTION

[0105] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0106] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0107] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0108] Example 1

[0109] See also Figure 1 The present invention provides a damage effect assessment system based on a large model, comprising:

[0110] The data acquisition module performs LIDAR scanning and remote sensing data acquisition to obtain point cloud data and image data of the target area;

[0111] Explosion terrain simulation module, used to determine the explosion point and its initial conditions, generate the initial mesh, and simulate the behavior of materials under the action of shock waves;

[0112] Numerical simulation module, used to simulate shock wave propagation, simulate material damage, and multi-scale coupling;

[0113] Multi-physics coupling simulation module, used to simulate the coupling effect of fluid mechanics and heat conduction, the coupling effect of radiation transmission and fluid mechanics, heat conduction, and the coupling effect of structural mechanics and heat conduction, fluid mechanics;

[0114] The present invention also provides a large model-based damage effect assessment system, comprising:

[0115] Step 1. Data collection and preprocessing: Use LIDAR and remote sensing technology to obtain high-resolution terrain data of the target area; use GIS system to process data and generate a three-dimensional terrain model; in addition, collect microstructure and mechanical property data of relevant materials to provide a data basis for microscale simulation;

[0116] According to the size and terrain characteristics of the target area, corresponding LIDAR equipment and remote sensing technology, including UAV LIDAR, airborne LIDAR, and satellite remote sensing, are used to formulate flight paths, scanning frequencies, and altitude parameters to cover the target area;

[0117] Perform LIDAR scanning and remote sensing data collection to obtain point cloud data and image data of the target area;

[0118] Perform preliminary data processing, including denoising, filtering, and point cloud classification to separate ground points from non-ground points;

[0119] Fuse and integrate multi-source data, including LIDAR point cloud, remote sensing images, and geographic information, to generate a unified terrain dataset;

[0120] The triangulated mesh algorithm TIN and the grid DEM interpolation algorithm are used to generate the terrain surface model;

[0121] In step 1, the microstructure and mechanical properties data of relevant materials are collected simultaneously:

[0122] Includes the types of major building and geological materials in the target area, i.e., concrete, steel, soil;

[0123] Material microstructure and mechanical property data, including elastic modulus, density, and fracture toughness;

[0124] Step 2. Model construction and grid generation: construct the computational domain according to the terrain model, and generate computational grids of different complexity based on adaptive grid technology; determine the explosion point and its initial conditions, including the explosion equivalent and the explosion center height; construct the microstructure model of the material, and use the discrete element method to simulate the behavior of the material under the action of the shock wave;

[0125] The way to construct the computational domain based on the terrain model is:

[0126] Import the 3D terrain model generated in step 1 into the 3D simulation platform, and determine the spatial range of the calculation domain according to the terrain characteristics and the impact range of the nuclear explosion. The calculation domain includes the explosion center and the surrounding area, and covers all important paths and reflection areas of shock wave propagation.

[0127] Divide the computational domain into multiple sub-areas, and make detailed divisions in complex terrain areas, such as densely built-up areas and mountainous areas;

[0128] Then, computational grids that adapt to different complexities are generated, and the resolution and density of the initial grid are set according to the actual terrain complexity and simulation accuracy;

[0129] Generate the initial grid in the computational domain and optimize it using adaptive grid technology;

[0130] Use finer grids in complex terrain and key areas, i.e. around buildings and where terrain changes suddenly, to improve local simulation accuracy; use coarser grids in other areas to save computing resources;

[0131] The explosion point and its initial conditions are determined as follows:

[0132] Determine and mark the epicenter of a nuclear explosion based on actual conditions or hypothetical scenarios;

[0133] Set the explosion equivalent and explosion center height, and set the initial conditions of the explosion, including the explosion energy release rate, initial shock wave pressure and velocity distribution;

[0134] Input the explosion point location and initial conditions into the three-dimensional simulation platform;

[0135] Then the microstructure model of the material is constructed, and the discrete element method DEM is used to simulate the microstructure of the material;

[0136] Define the geometry, size, and interaction forces of particles or cells in the microstructural model;

[0137] Simulate the behavior of materials under shock waves at a microscopic scale and analyze the displacement, deformation and failure mechanism of particles or units;

[0138] Output simulation results;

[0139] Step 2: Construct a refined computational domain and grid model to simulate the propagation path and intensity attenuation of nuclear explosion shock waves under complex terrain conditions; at the same time, use the discrete element method to simulate the microstructure of the material and provide material behavior data;

[0140] The methods of generating computational grids of different complexity based on adaptive grid technology include:

[0141] According to the terrain complexity and simulation accuracy requirements, the resolution Δx0 and density ρ0 of the initial grid are set;

[0142] Select tetrahedral mesh and hexahedral mesh to generate the initial mesh Ω0 in the computational domain;

[0143] Calculate the error estimate E in the initial grid i , the mesh refinement or coarsening is determined by estimating the error of the local solution;

[0144] Using gradient-based error estimation: E i =|▽·(φ h -φ ref )|, where φ h is the solution for the current grid, φ ref is the reference solution (high-resolution solution), ▽ represents the gradient operator;

[0145] According to the error estimate E i Identify the mesh cells that need to be refined or coarsened:

[0146] Refinement strategy: Refine the mesh in high error areas. The refinement factor γ is defined as: Δx i+1 =Δx i / γ,γ>1;

[0147] Coarsening strategy: Coarsening the grid in low error areas, the coarsening factor β is defined as: Δx i+1 =Δx i ×β,β<1; here Δx i Indicates the size of the current grid cell, Δx i+1 It represents the size of the grid unit after the next grid refinement or coarsening, that is, the grid resolution of the i+1th step;

[0148] The mesh resolution is adjusted by an adaptive mesh generation algorithm, which uses a variational principle-based approach to generate an adaptive mesh by minimizing an error functional: Where λ is the regularization parameter used to balance the variation of error and mesh size, and Ω is the computational domain;

[0149] Regenerate the mesh and adjust the mesh element size according to the refinement and coarsening rules;

[0150] Step 3. Numerical simulation and multi-scale coupling. On a macro scale, the CFD algorithm is used to perform numerical simulation of the propagation of explosion shock waves, and the propagation path, intensity attenuation and secondary reflection effect of shock waves under complex terrain conditions are analyzed; on a micro scale, the microstructural changes and damage mechanisms of materials under the action of shock waves are simulated; CFXDEM and FluentDEM software are selected for multi-scale coupling, and the micro-simulation results are fed back to the macro model. The parameters of the macro model are dynamically adjusted through adaptive grid technology to improve the simulation accuracy;

[0151] Numerical simulations on a macro scale include:

[0152] Select ANSYS Fluent and OpenFOAM fluid mechanics CFD software, and import the calculation domain and adaptive mesh model generated in step 2;

[0153] According to the explosion point and its initial conditions, the boundary conditions and initial conditions of the CFD model are set;

[0154] Define the boundary type of the computational domain, including solid boundary and open boundary; and fluid properties, including air density and viscosity;

[0155] Use the explosion energy release model to simulate the initial energy release and shock wave generation of a nuclear explosion, and set the parameters of the explosion source, including the energy release rate and initial pressure distribution;

[0156] Run CFD simulations to calculate the propagation path, intensity attenuation and secondary reflection effects of shock waves in complex terrain conditions;

[0157] Analyze CFD simulation results and extract shock wave propagation path, pressure distribution, and velocity field data;

[0158] Simulations at the microscopic scale include:

[0159] Select LAMMPS and EDEM discrete element method simulation software and import the material microstructure model constructed in step 2;

[0160] According to the collected material property data, the material properties of particles or units in the microstructure model are set;

[0161] Define the interaction force model between particles or units, including contact force, friction force, and adhesion force;

[0162] The shock wave pressure distribution data obtained from the macro-scale CFD simulation is used as load input and applied to the microstructure model;

[0163] Simulate the behavior of materials under shock waves and analyze the displacement, deformation and failure mechanism of particles or units;

[0164] Analyze DEM simulation results and extract the damage mode and microstructure change data of materials under the action of shock waves;

[0165] The multi-scale coupling mode is:

[0166] Feedback the material failure data and stress-strain relationships obtained from micro-scale simulations to the macro CFD model;

[0167] Update material properties and failure model parameters in the macro model to reflect changes in the microstructure;

[0168] Adaptive mesh technology is used to dynamically adjust the mesh resolution of the macro CFD model based on the data fed back from the micro simulation.

[0169] Improve the grid resolution in key areas, i.e., material damage areas and shock wave reflection areas, to improve calculation accuracy;

[0170] Run multi-scale coupled simulations, combining the results of macro CFD and micro DEM for joint calculations;

[0171] Analyze the interaction of multiple physical fields in coupled simulations and comprehensively evaluate the combined impact of shock waves, thermal effects, and radiation effects;

[0172] This achieves multi-scale coupling of CFD simulation at the macro scale and DEM simulation at the micro scale; uses multi-scale coupling simulation technology to more accurately predict the propagation of explosion shock waves and their damage effects under complex terrain conditions, improving the accuracy and reliability of assessment results; and provides more comprehensive and dynamic damage assessment results through adaptive grid technology and multi-physics field coupling simulation.

[0173] The numerical simulation method of CFD explosion shock wave propagation on a macro scale is:

[0174] Import the adaptive grid and terrain model generated in step 2 into the simulation environment, set the explosion point location and initial explosion parameters, set the explosion equivalent to Q, the initial pressure to P0 and the density to ρ0;

[0175] The explosion energy release is expressed as: Where E is the total energy density, u is the initial velocity, and γ represents the specific heat ratio;

[0176] Set fluid boundary conditions and solid boundary conditions for terrain and buildings;

[0177] Perform CFD simulation, solve the fluid equations, and use the Navier-Stokes equations to describe fluid motion: Among them, θ is the partial derivative, u represents the velocity field, τ is the stress tensor, g is the gravitational acceleration, ▽ is the gradient operator, ρuu represents the tensor product of density ρ multiplied by the velocity field u, describing the convection term of the momentum flow, PΙ represents the pressure P multiplied by the unit tensor Ι, representing the static pressure term of the fluid, ▽·τ+ρg represents the divergence term of the stress tensor τ plus the density ρ multiplied by the gravitational acceleration g, describing the effect of external forces and gravity on the fluid;

[0178] Compute the pressure wave advance and decay using the blast wave propagation model: Among them, r represents the distance from the explosion center to the observation point, r0 is the initial distance, α and β are empirical parameters, and t is the explosion time from the explosion center to the observation point;

[0179] Coupled kinetic and energy equations: Where E is the total energy density and Q is the heat source term;

[0180] Extract and analyze shock wave propagation path, pressure distribution, and velocity field data;

[0181] The simulation method of DEM microstructure changes and damage mechanisms at the micro scale is as follows:

[0182] Import the constructed material microstructure model to define the geometry and density of particles or units p , elastic modulus E p , fracture toughness K p ;

[0183] Define the interaction force model between particles, including the contact force F c , friction force F f Adhesion force F a ;

[0184] Set the initial position and velocity of the particles and apply shock wave load based on CFD simulation results;

[0185] Perform a DEM simulation and use Newton's second law to solve the particle motion equation: Among them, m i is the particle mass, r i is the particle position, i represents the index of the current particle, j represents the index of other particles that interact with particle i, and F c,ij 、F f,ij 、F a,ij represents friction, adhesion, and fracture;

[0186] Simulate the breaking of interparticle bonds using a fracture mechanics model: Among them, F b is the breaking force, K b is the fracture stiffness coefficient, Δl is the displacement change, l0 is the initial length, and α is the material constant;

[0187] Thermal conduction and mechanical coupling effect: Q ij =-k▽T ij , where Q ij is the heat flow, k is the thermal conductivity, ▽T ij is the temperature gradient;

[0188] Extract the displacement, deformation and fracture data of particles and analyze the damage mechanism of materials under the action of shock waves;

[0189] Generate detailed reports including particle motion, deformation and damage, and output data for multi-scale coupling;

[0190] Combine micro- and macro-scale simulation methods to refine the shock wave propagation characteristics and physical mechanisms at different scales, and use multi-scale simulation technology to refine the simulation at the micro- and macro-scales to improve the accuracy of shock wave propagation characteristics;

[0191] Step 4. Multi-physics coupling simulation, introducing thermal effect, radiation effect and structural mechanics coupling simulation, comprehensively evaluates the comprehensive damage effect of nuclear explosion on different materials and structures; uses multi-physics coupling algorithm to comprehensively analyze shock waves, heat conduction, radiation propagation and their comprehensive impact on buildings and terrain;

[0192] Introducing coupled simulation of thermal effects, radiation effects and structural mechanics:

[0193] Select ANSYS Multiphysics, COMSOL Multiphysics, and Abaqus multi-physics field coupling simulation platforms, and import the multi-scale coupling simulation results of step 3 as initial conditions and boundary conditions;

[0194] Establish corresponding mathematical and physical models for each physical field, including fluid mechanics, heat conduction, radiation transfer, and structural mechanics;

[0195] Define the coupling relationship between different physical fields in the simulation platform, including thermal-structural coupling and fluid-structural coupling;

[0196] Set the interaction parameters between physical fields, including thermal conductivity, radiation absorption coefficient, and material thermal expansion coefficient;

[0197] Establish a thermal effect model produced by a nuclear explosion, simulate the impact of high temperature on surrounding materials and structures, define thermal conduction boundary conditions, including radiation heat source, convection heat transfer, and heat conduction, run thermal conduction simulation, and analyze high-temperature heat conduction processes and temperature distribution;

[0198] Establish a radiation transmission model to simulate the electromagnetic radiation and optical radiation effects produced by a nuclear explosion;

[0199] Establish a structural mechanics model to simulate the destructive effects of nuclear explosion shock waves and thermal effects on buildings and terrain;

[0200] Run multiphysics coupled simulations to comprehensively analyze shock waves, heat conduction, radiation propagation, and their combined effects on buildings and terrain.

[0201] The present invention uses LIDAR and remote sensing technology to obtain high-resolution terrain data of a target area, and uses a GIS system to process data to generate a three-dimensional terrain model; constructs a calculation domain according to the terrain model, generates a calculation grid adapted to different complexities based on an adaptive grid technology, determines the explosion point and its initial conditions, and constructs a microstructure model of the material, and uses a discrete element method to simulate the behavior of the material under the action of a shock wave. Specifically: the three-dimensional terrain model is imported into a three-dimensional simulation platform, the calculation domain range is determined, and the calculation domain is divided into a plurality of sub-areas; generates an initial grid, applies an adaptive grid technology to optimize the grid, uses a finer grid in complex terrain and key areas, and improves local simulation accuracy; determines the explosion point and its initial conditions, sets the initial explosion conditions, and constructs a microstructure model of the material, performs a microstructure simulation of the material, and analyzes the behavior of the material under the action of a shock wave;

[0202] In the stage of numerical simulation and multi-scale coupling, CFD algorithm is used on macro scale to carry out numerical simulation of explosion shock wave propagation, and analyze the propagation path, intensity attenuation and secondary reflection effect of shock wave under complex terrain conditions; on micro scale, DEM method is used to simulate the microstructural changes and damage mechanism of materials under the action of shock wave;

[0203] During the multi-physics field coupling simulation stage, thermal effect, radiation effect and structural mechanics coupling simulation are introduced to comprehensively evaluate the comprehensive destructive effects of nuclear explosions on different materials and structures; a multi-physics field coupling simulation platform is selected to import multi-scale coupling simulation results, establish corresponding mathematical models and physical models for each physical field, define the coupling relationship between different physical fields, and set the interaction parameters between physical fields; run multi-physics field coupling simulation to comprehensively analyze shock waves, heat conduction, radiation propagation and their combined impact on buildings and terrain.

[0204] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A damage effect assessment system based on a large model, comprising a data acquisition module, an explosion terrain simulation module, a numerical simulation module and a multi-physical field coupling simulation module, characterized in that: The data acquisition module performs LIDAR scanning and remote sensing data acquisition to obtain point cloud data and image data of the target area; Explosion terrain simulation module, used to determine the explosion point and its initial conditions, generate the initial mesh, and simulate the behavior of materials under the action of shock waves; Numerical simulation module, used to simulate shock wave propagation, simulate material damage, and multi-scale coupling; Multi-physics coupling simulation module, used to simulate the coupling effect of fluid mechanics and heat conduction, the coupling effect of radiation transmission and fluid mechanics, heat conduction, and the coupling effect of structural mechanics and heat conduction, fluid mechanics; The evaluation steps of this system include: Step 1. Data collection and preprocessing: Use LIDAR and remote sensing technology to obtain high-resolution terrain data of the target area; use GIS system to process data and generate a three-dimensional terrain model; Step 2. Model construction and grid generation: construct the computational domain according to the terrain model, and generate computational grids of different complexity based on adaptive grid technology; determine the explosion point and its initial conditions, including the explosion equivalent and the explosion center height; construct the microstructure model of the material, and use the discrete element method to simulate the behavior of the material under the action of the shock wave; Step 3. Numerical simulation and multi-scale coupling. On a macro scale, use CFD algorithm to perform numerical simulation of explosion shock wave propagation, analyze the propagation path, intensity attenuation and secondary reflection effect of shock waves under complex terrain conditions; on a micro scale, simulate the microstructural changes and damage mechanism of materials under the action of shock waves; perform multi-scale coupling, feed back micro-simulation results to the macro model, and dynamically adjust the parameters of the macro model through adaptive grid technology; Step 4. Multi-physics coupling simulation, introducing thermal effect, radiation effect and structural mechanics coupling simulation, comprehensively evaluates the comprehensive damage effect of nuclear explosion on different materials and structures; uses multi-physics coupling algorithm to comprehensively analyze shock waves, heat conduction, radiation propagation and their comprehensive impact on buildings and terrain; In step 4, thermal effect, radiation effect and structural mechanics coupling simulation are introduced: Select ANSYS Multiphysics, COMSOL Multiphysics, and Abaqus multi-physics field coupling simulation platforms, and import the multi-scale coupling simulation results of step 3 as initial conditions and boundary conditions; Establish corresponding mathematical and physical models for each physical field, including fluid mechanics, heat conduction, radiation transfer, and structural mechanics; Define the coupling relationship between different physical fields in the simulation platform, including thermal-structural coupling and fluid-structural coupling; Set the interaction parameters between physical fields, including thermal conductivity, radiation absorption coefficient, and material thermal expansion coefficient; Establish a thermal effect model produced by a nuclear explosion, simulate the impact of high temperature on surrounding materials and structures, define thermal conduction boundary conditions, including radiation heat source, convection heat transfer, and heat conduction, run thermal conduction simulation, and analyze high-temperature heat conduction processes and temperature distribution; Establish a radiation transmission model to simulate the electromagnetic radiation and optical radiation effects produced by a nuclear explosion; Establish a structural mechanics model to simulate the destructive effects of nuclear explosion shock waves and thermal effects on buildings and terrain; Run multi-physics coupled simulations to comprehensively analyze shock waves, heat conduction, radiation propagation and their combined effects on buildings and terrain; The data collection and preprocessing steps in step 1 include: According to the size and terrain characteristics of the target area, corresponding LIDAR equipment and remote sensing technology, including UAV LIDAR, airborne LIDAR, and satellite remote sensing, are used to formulate flight paths, scanning frequencies, and altitude parameters to cover the target area; Perform LIDAR scanning and remote sensing data collection to obtain point cloud data and image data of the target area; Perform preliminary data processing, including denoising, filtering, and point cloud classification to separate ground points from non-ground points; Fuse and integrate multi-source data, including LIDAR point cloud, remote sensing images, and geographic information, to generate a unified terrain dataset; The triangulated mesh algorithm TIN and the grid DEM interpolation algorithm are used to generate the terrain surface model; In step 1, the microstructure and mechanical properties data of relevant materials are collected simultaneously: Includes the types of major building and geological materials in the target area, i.e., concrete, steel, soil; Material microstructure and mechanical property data, including elastic modulus, density, and fracture toughness; The method of constructing the computational domain based on the terrain model in step 2 is: Import the 3D terrain model generated in step 1 into the 3D simulation platform, and determine the spatial range of the calculation domain according to the terrain characteristics and the impact range of the nuclear explosion. The calculation domain includes the explosion center and the surrounding area, and covers all important paths and reflection areas of shock wave propagation. Divide the computational domain into multiple sub-areas, and make detailed divisions in complex terrain areas, such as densely built-up areas and mountainous areas; Then, computational grids that adapt to different complexities are generated, and the resolution and density of the initial grid are set according to the actual terrain complexity and simulation accuracy; Generate the initial grid in the computational domain and optimize it using adaptive grid technology; Use finer grids in complex terrain and key areas, i.e. around buildings and where terrain changes suddenly; use coarser grids in other areas to save computing resources; The explosion point and its initial conditions are determined in step 2 as follows: Determine and mark the epicenter of a nuclear explosion based on actual conditions or hypothetical scenarios; Set the explosion equivalent and explosion center height, and set the initial conditions of the explosion, including the explosion energy release rate, initial shock wave pressure and velocity distribution; Input the explosion point location and initial conditions into the three-dimensional simulation platform; Then the microstructure model of the material is constructed, and the discrete element method DEM is used to simulate the microstructure of the material; Define the geometry, size, and interaction forces of particles or cells in the microstructural model; Simulate the behavior of materials under shock waves at a microscopic scale and analyze the displacement, deformation and failure mechanism of particles or units; Output simulation results; The methods of generating computational grids of different complexity based on adaptive grid technology include: According to the terrain complexity and simulation accuracy requirements, the resolution Δx0 and density ρ0 of the initial grid are set; Select tetrahedral mesh and hexahedral mesh to generate the initial mesh Ω0 in the computational domain; Calculate the error estimate E in the initial grid i , the mesh refinement or coarsening is determined by estimating the error of the local solution; Using gradient-based error estimation: E i =|▽·(φ h -φ ref )|, where φ h is the solution for the current grid, φ ref is the reference solution, ▽ represents the gradient operator; According to the error estimate E i Identify the mesh cells that need to be refined or coarsened: Refinement strategy: Refine the mesh in high error areas. The refinement factor γ is defined as: Δx i+1 =Δx i / γ,γ>1; Coarsening strategy: Coarsening the grid in low error areas, the coarsening factor β is defined as: Δx i+1 =Δx i ×β,β<1; here Δx i Indicates the size of the current grid cell, Δx i+1 It represents the size of the grid unit after the next grid refinement or coarsening, that is, the grid resolution of the i+1th step; The mesh resolution is adjusted by an adaptive mesh generation algorithm, which uses a variational principle-based approach to generate an adaptive mesh by minimizing an error functional: Where λ is the regularization parameter used to balance the variation of error and mesh size, and Ω is the computational domain; Regenerate the mesh, adjusting the mesh element size according to the refinement and coarsening rules.

2. The damage effect assessment system based on a large model according to claim 1, characterized in that: Numerical simulations on a macro scale include: Select ANSYS Fluent and OpenFOAM fluid mechanics CFD software, and import the calculation domain and adaptive mesh model generated in step 2; According to the explosion point and its initial conditions, the boundary conditions and initial conditions of the CFD model are set; Define the boundary type of the computational domain, including solid boundary and open boundary; and fluid properties, including air density and viscosity; Use the explosion energy release model to simulate the initial energy release and shock wave generation of a nuclear explosion, and set the parameters of the explosion source, including the energy release rate and initial pressure distribution; Run CFD simulations to calculate the propagation path, intensity attenuation and secondary reflection effects of shock waves in complex terrain conditions; Analyze CFD simulation results and extract shock wave propagation path, pressure distribution, and velocity field data; Simulations at the microscopic scale include: Select LAMMPS and EDEM discrete element method simulation software and import the material microstructure model constructed in step 2; According to the collected material property data, the material properties of particles or units in the microstructure model are set; Define the interaction force model between particles or units, including contact force, friction force, and adhesion force; The shock wave pressure distribution data obtained from the macro-scale CFD simulation is used as load input and applied to the microstructure model; Simulate the behavior of materials under shock waves and analyze the displacement, deformation and failure mechanism of particles or units; Analyze the DEM simulation results and extract the material's damage mode and microstructure change data under the action of shock waves.

3. The damage effect assessment system based on a large model according to claim 2 is characterized in that: The multi-scale coupling mode is: Feedback the material failure data and stress-strain relationships obtained from micro-scale simulations to the macro CFD model; Update material properties and failure model parameters in the macro model to reflect changes in the microstructure; Adaptive mesh technology is used to dynamically adjust the mesh resolution of the macro CFD model based on the data fed back from the micro simulation. Improve the grid resolution in key areas, i.e., material damage areas and shock wave reflection areas, to improve calculation accuracy; Run multi-scale coupled simulations, combining the results of macro CFD and micro DEM for joint calculations; Analyze the interaction of multiple physical fields in coupled simulations and comprehensively evaluate the combined impact of shock waves, thermal effects, and radiation effects.

4. The damage effect assessment system based on a large model according to claim 3 is characterized in that: The numerical simulation method of CFD explosion shock wave propagation on a macro scale is: Import the adaptive grid and terrain model generated in step 2 into the simulation environment, set the explosion point location and initial explosion parameters, set the explosion equivalent to Q, the initial pressure to P0 and the density to ρ0; The explosion energy release is expressed as: Where E is the total energy density, u is the initial velocity, and γ represents the specific heat ratio; Set fluid boundary conditions and solid boundary conditions for terrain and buildings; Perform CFD simulation, solve the fluid equations, and use the Navier-Stokes equations to describe fluid motion: Among them, θ is the partial derivative, u represents the velocity field, τ is the stress tensor, g is the gravitational acceleration, ▽ is the gradient operator, ρuu represents the tensor product of density ρ multiplied by the velocity field u, describing the convection term of the momentum flow, PΙ represents the pressure P multiplied by the unit tensor Ι, representing the static pressure term of the fluid, ▽·τ+ρg represents the divergence term of the stress tensor τ plus the density ρ multiplied by the gravitational acceleration g, describing the effect of external forces and gravity on the fluid; Compute the pressure wave advance and decay using the blast wave propagation model: Among them, r represents the distance from the explosion center to the observation point, r0 is the initial distance, α and β are empirical parameters, and t is the explosion time from the explosion center to the observation point; Coupled kinetic and energy equations: Where E is the total energy density and Q is the heat source term; Extract and analyze shock wave propagation path, pressure distribution, and velocity field data.

5. The damage effect assessment system based on a large model according to claim 4 is characterized in that: The simulation method of DEM microstructure changes and damage mechanisms at the micro scale is as follows: Import the constructed material microstructure model to define the geometry and density of particles or units p , elastic modulus E p , fracture toughness K p ; Define the interaction force model between particles, including the contact force F c , friction force F f Adhesion force F a ; Set the initial position and velocity of the particles and apply shock wave loads based on CFD simulation results; Perform a DEM simulation and use Newton's second law to solve the particle motion equation: Among them, m i is the particle mass, r i is the particle position, i represents the index of the current particle, j represents the index of other particles that interact with particle i, and F c,ij 、F f,ij 、F a,ij represents friction, adhesion, and fracture; Simulate the breaking of interparticle bonds using a fracture mechanics model: Among them, F b is the breaking force, K b is the fracture stiffness coefficient, Δl is the displacement change, l0 is the initial length, and α is the material constant; Thermal conduction and mechanical coupling effect: Q ij =-k▽T ij , where Q ij is the heat flow, k is the thermal conductivity, ▽T ij is the temperature gradient; Extract the displacement, deformation and fracture data of particles and analyze the damage mechanism of materials under the action of shock waves; Generate detailed reports on particle motion, deformation, and failure, and export data for multiscale coupling.

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