Efficient modeling method for simulating anti-knock performance of concrete-filled steel tubular column based on SALE method

Abstract

The invention discloses an efficient modeling method for simulating the anti-knock performance of a concrete filled steel tubular column based on an SALE method. The method comprises the following steps: creating an engineering material model by using an LS-DYNA module in an ANSYS Workbench environment; rapidly constructing an explosion scene model of the concrete filled steel tube through a Python code command stream in the SpaceClaim; and grid division is carried out on the Mechnical GUI interface, boundary conditions are applied, finally, numerical calculation is carried out by the LS-RUN, and the dynamic response of the concrete filled steel tubular column under the blast load is determined. The modeling method has the characteristics of high efficiency, three-dimensional intuition and integration, the explosive load simulation technology based on the SALE method enables a numerical simulation result to be highly matched with a test result, the limitation of pure digital input in a traditional method is successfully avoided, the problem of data incompatibility caused by pre-processing depending on external software in the past is avoided, and the method is suitable for popularization and application. The whole process is completed in a Workbench platform, and the accuracy and efficiency of dynamic response prediction of the concrete filled steel tubular column under the blast load are greatly improved.

Description

Technical Field

[0001] The invention relates to the field of methods for numerically simulating steel tube concrete columns under explosion loads using finite element software, and in particular to an efficient modeling method for simulating the explosion resistance of steel tube concrete columns based on a SALE method. Background Art

[0002] With the increasing requirements for the safety of engineering structures, concrete-filled steel tube columns (CFST) have received extensive attention and application in the field of construction. CFST columns are often used in high-rise buildings, bridges, and structures with strong explosion resistance due to their excellent compression, bending, and shear resistance. However, the dynamic response of CFST columns under explosion loads is highly complex, involving factors such as nonlinear material behavior, stress wave propagation, and multi-physics field coupling. Due to the highly nonlinear characteristics of these factors, traditional test methods often cannot fully meet actual needs. Therefore, it is of great significance to use numerical simulation methods to analyze the response of CFST columns under explosion loads. ANSYS / LS-DYNA, as a widely used finite element analysis software, has shown superior performance in the fields of dynamic response and explosion load simulation. It can provide accurate numerical solutions by considering complex factors such as material nonlinearity, contact mechanics, and fluid-solid coupling through precise finite element discretization. Therefore, the numerical simulation of CFST columns under explosion loads using ANSYS / LS-DYNA can provide effective support for design optimization and reduce the high cost and time consumption in experimental research.

[0003] At present, the traditional APDL calculation method is usually used when using ANSYS / LS-DYNA for numerical simulation of the explosion response of steel tube concrete columns. This method requires a large number of manual input parameters, and the model can only be adjusted by parameter input, but it is impossible to intuitively stretch or modify the geometry in the three-dimensional model. This method is not only time-consuming and cumbersome, but also requires the calculation of coordinate positions and geometric parameters in advance, and it is easy to affect the accuracy of the final simulation results due to operational errors or inaccurate models. In addition, the traditional ANSYS interface operation is relatively complicated, and most of them are English interfaces, which has a high technical threshold for beginners. In the process of meshing complex models, the traditional interface also has certain limitations, and there is a lack of material models and keywords suitable for explosion load analysis. Therefore, in practical applications, it is usually necessary to use other software for pre-processing, such as APDL, SolidWorks, LS-PrePost, HyperMesh, SimLab, PAM-CRASH and MSC Patran. This cross-platform operation increases the risk of data compatibility issues, and the import and save steps involved in each operation are relatively cumbersome, which further reduces the overall work efficiency and increases the difficulty and cost of later modification and optimization. Summary of the invention

[0004] The present invention provides an efficient modeling method for simulating the explosion resistance of steel tube concrete columns based on the SALE method. The method is based on the ANSYS Workbench platform and combined with its pre-processing module to realize the automation of the model building process and data sharing. Unlike traditional explosion resistance simulation methods, which usually rely on multiple software for data processing and interaction, the present invention integrates data streams in the ANSYS Workbench environment and updates them in real time without relying on external software, thereby ensuring dynamic sharing of data and improving the accuracy and consistency of numerical simulation.

[0005] In order to further improve the convenience of model operation, the present invention adopts the Python script function in the SpaceClaim software. Through the pre-set script record, the user can quickly modify the key modeling parameters and realize one-click model generation. This script function significantly improves the reusability and optimization efficiency of the model, so that the model can be flexibly adjusted under different parameter requirements, thereby avoiding the cumbersome steps of frequent model reconstruction in the traditional method. In specific operations, users can quickly generate and adjust model parameters through an intuitive graphical interface combined with Python scripts, significantly shortening the time required for manual modeling and adjustment. In addition, the present invention supports batch modeling and parametric analysis, and users can generate new three-dimensional models by simply modifying key parameters with one click. During the model building process, with the help of the sharing function, the system automatically identifies and defines the contact surface between the steel pipe and the concrete column, ensuring the precise interaction between the entities during the simulation process. Finally, after the modeling is completed, the generated geometric model will be automatically imported into the ANSYS Mechanical module for further finite element analysis, thereby achieving seamless connection between the model building and analysis processes, ensuring the integration of the entire modeling and analysis process.

[0006] In addition, the modeling method of the present invention supports direct structural adjustment in the three-dimensional model, including operations such as stretching, shrinking, moving and cutting, making the model modification process more intuitive and convenient. This function not only simplifies the model adjustment steps, but also improves the work efficiency of researchers in model construction and parameter modification, and is particularly suitable for multiple simulations and optimization analysis.

[0007] In order to solve the above technical problems, a technical solution adopted by the present invention is: an efficient modeling method for simulating the explosion resistance of steel tube concrete columns based on the SALE method, characterized in that it includes the following steps:

[0008] Step 1: Initialize the LS-DYNA module: Open the finite element analysis software ANSYS Workbench, select the LS-DYNA module, and initialize the engineering environment;

[0009] Step 2: Define material parameters: In the engineering data module, define the material parameters of the steel pipe and concrete, including elastic modulus, density, Poisson's ratio and failure criterion, and define the material model and state equation of the explosive and air domain to ensure that the actual physical performance requirements are met;

[0010] Step 3: Quickly build the model: Use the Python code command flow in SpaceClaim to quickly generate the geometric model and explosion load scenario required for simulation by simply inputting the key dimensions of steel tube concrete columns, explosives, and air;

[0011] Step 4: Apply boundary conditions and loads: After loading the SpaceClaim geometry model in the Mechanical module, set the characteristic parameters of the explosion load based on the SALE method, divide the meshes for all entities, and add boundary conditions to ensure that the simulation scene truly restores the actual explosion situation;

[0012] Step 5. Solution and calculation: Call the LS-RUN solver to solve and dynamically track the response process of the column structure to verify the accuracy of the simulation results.

[0013] The beneficial effect of the present invention is that the SpaceClaim modeling tool of the LS-DYNA module in the ANSYS Workbench integrated environment is used, and the modeling command flow code written in Python script is combined to realize the flexible modification and one-key generation of the key parameters of the steel tube concrete column model. The method significantly improves the modeling efficiency, simplifies the operation process, and optimizes the user operation experience through intuitive graphical interface display. Compared with the traditional modeling method, the present invention effectively avoids the technical obstacles caused by cumbersome multiple manual inputs and non-Chinese interfaces, greatly improves the convenience of operation, reduces the learning curve, and enhances the compatibility between software. In the process of model construction, real-time sharing and dynamic updating of data are realized. Through automated modeling and parameter adjustment, each step can be seamlessly connected in the ANSYS Workbench environment, ensuring the smooth generation of K files and subsequent calculations, and ensuring the integrity of model data and the consistency of workflow. This integrated modeling and analysis process not only improves work efficiency, but also reduces the occurrence of human errors. By comparing with experimental data, the method of the present invention performs well in error control, and the error range is kept within a reasonable range, ensuring the high-precision simulation of the dynamic response of steel tube concrete columns under explosion loads based on the SALE method. In summary, the present invention realizes the high efficiency, precision and reliability of the explosion-resistant performance modeling method of steel tube concrete columns, and provides a more advanced and reliable numerical simulation tool for the explosion-resistant design of engineering structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1This is a flow chart of an efficient modeling method for simulating the explosion resistance of steel tube concrete columns based on the SALE method proposed by the present invention;

[0015] Figure 2 This is a diagram of the traditional APDL interface and the SpaceClaim Python interface;

[0016] Figure 3 This is a schematic diagram of a quick modeling excerpt using Python in SpaceCliam of the present invention;

[0017] Figure 4 It is a finite element model (grid) of a steel tube concrete column explosion scene quickly established using the present invention;

[0018] Figure 5 It is a comparison chart of numerical simulation results obtained by using the present invention and test data;

[0019] Figure 6 It is a dynamic cloud diagram of explosive blast wave pressure in C3 scenario obtained by using the present invention;

[0020] Figure 7 The plastic strain cloud diagram of the steel pipe and concrete obtained by using the present invention; DETAILED DESCRIPTION

[0021] In view of the problems of cumbersome modeling, insufficient precision, and low efficiency in the existing numerical simulation of the explosion-resistant performance of steel tube concrete columns, the present invention develops an efficient modeling and simulation method based on the finite element software ANSYS / LS-DYNA. In the ANSYS Workbench environment, based on the SpaceClaim modeling tool and Python script function in the LS-DYNA module, the dynamic response simulation of steel tube concrete columns under explosion loads is realized. This method effectively improves the modeling accuracy and efficiency by simplifying the modeling process, automatically generating a three-dimensional model, and quickly adjusting key modeling parameters. Unlike traditional methods, the present invention realizes data sharing and real-time updating in an integrated environment, ensuring the integrity of the model and the continuity of calculations. By using ANSYS / LS-DYNA for numerical calculations and post-processing, the present invention can efficiently simulate the response characteristics of steel tube concrete columns under explosion loads, providing a more accurate and reliable numerical analysis tool for structural explosion-resistant design. The specific steps are as follows:

[0022] Step 1: Open Workbench and create an LS-DYNA module

[0023] In the ANSYS Workbench environment, first create the LS-DYNA module and rename the module according to project requirements for easy identification and annotation. This ensures effective management of various operations in a multi-module working environment.

[0024] Step 2: Define the steel pipe material model

[0025] Enter the engineering data interface of the LS-DYNA module and start to create a new material model for the steel pipe. Select the material type as isotropic elastic and input the Young's modulus, Poisson's ratio, bulk modulus and shear modulus of the steel pipe.

[0026] *MAT_PLASTIC_KINEMATIC model is used to simulate the plastic behavior of steel pipes, and the rate effect formula, yield stress (sipy), tangent modulus (Etan), hardening parameter (beta) and strain rate parameter (C) are configured. In addition, the effective plastic strain (fs) of the erosion unit is set to ensure the destructive performance of the material under extreme loads. These input parameters will ensure that the steel pipe material model can accurately simulate its elastic-plastic and destructive behavior under blast loads.

[0027] Step 3: Define the concrete, air, and explosive material models

[0028] Repeat step 2 to create material models for concrete, air, and explosives, and define the properties of different materials precisely:

[0029] Concrete material model: Call the MAT_Concrete_Damage_Rel3 (MAT072R3) model, which can accurately describe the dynamic response of concrete under blast loads. Enter specific strain rate parameters to enhance the accuracy of the model so that it can reflect the dynamic damage behavior of concrete.

[0030] The dynamic amplification factor CDIF of concrete compressive strength is determined by the following formula:

[0031]

[0032] The dynamic amplification factor TDIF of concrete tensile strength is determined by the following formula:

[0033]

[0034] In the formula, f cd The strain rate of concrete is The corresponding dynamic compressive strength, f cs is the static compressive strength of concrete, f td for

[0035] The strain rate of concrete is The corresponding dynamic tensile strength, f ts is the static tensile strength of concrete, is the strain rate of concrete under blast load;

[0036] The strain rate effect DIF of steel becomes:

[0037]

[0038] The strain rate of steel is The yield strength at y is the yield strength of steel, and parameters D and P are strain rate parameters

[0039] Step 4: Call Python command in SpaceClaim to generate model

[0040] Open SpaceClaim and call the Python command window to import the code for the created steel pipe, concrete, explosives, and air models. According to project requirements, key parameters such as geometric dimensions and material properties can be flexibly adjusted. Edit the relevant code in the Python script and press F5 to run it to automatically generate a 3D model. This step greatly simplifies the modeling process, allowing users to quickly complete the conversion from code to geometry. If you need to fine-tune the geometric model, users can use tools to directly adjust the model locally to achieve refined modeling.

[0041] Step 5: Load the model to the Mechanical interface for subsequent analysis

[0042] After completing the creation of the 3D model, users can load the geometric model directly into the Mechanical interface through SpaceClaim. In the Mechanical interface, users can further assign material properties, mesh, and define boundary conditions. Use the Mechanical meshing function to ensure that the mesh is structured and refined to adapt to the characteristics of different materials such as steel pipes, concrete, explosives, and air.

[0043] Step 6: Configure materials, connection settings, and boundary conditions

[0044] Enter the setting stage of the Mechanical interface. First, assign materials to ensure that each material model is applied to the corresponding geometry. Then, insert the Euler / Lagrangian coupling, select the steel tube concrete column as the Lagrangian part, the explosive as the SALE filler, and the air as the SALE domain to simulate the propagation of the explosion wave in different media. Set the number of coupling points to 3 to ensure the effective transmission of dynamic information. Finally, add boundary conditions, including setting the detonation point of the explosive, the non-reflecting boundary of the air, and fixing the bottom of the steel tube concrete column to simulate the actual boundary conditions.

[0045] Step 7: Set calculation parameters and export K file

[0046] In the calculation settings, users can select the appropriate simulation duration, configure the hourglass model to ensure the stability of the calculation process, and set the animation and curve output frequency according to needs to obtain real-time simulation progress. After the configuration is completed, all setting data is exported as a K file (.k), which contains complete node data, material properties, meshes and boundary conditions.

[0047] Step 8: Run the LS-RUN solver and perform post-processing

[0048] Finally, the generated K file is solved using the LS-RUN solver. According to the computer configuration, the number of CPU cores and memory size are set, and the solve command is entered in the command line to start the calculation. After the calculation is completed, the results are imported into LS-PrePost for post-processing to intuitively analyze the dynamic response characteristics of steel tube concrete columns under explosion loads, thereby providing accurate data support for explosion-resistant design.

[0049] Implementation case 1:

[0050] The TNT charge of specimen C2 is 5kg, the explosion distance is 0.2m, the explosive is a cube with a length, width and height of 125×100×250mm, the charge height is 0.5m, and the proportional distance Z is 0.17. The structural characteristics of the steel tube concrete column are a height of 2.5m, an outer steel tube diameter of 325mm and a thickness of 6mm, an inner steel tube diameter of 159mm and a thickness of 6mm, and a circular cross-sectional shape. The steel yield strength f of the specimen y is 345MPa, the axial compressive strength of concrete is f cu It is 33.1MPa, and the geometric dimensions of the air domain are 410×590×2500mm.

[0051] Implementation case 2:

[0052] The TNT charge of specimen C3 is 8kg, the explosion distance is also 0.2m, the explosive is a cube with a length, width and height of 200×100×250mm, and the charge height is 0.5m, but its proportional distance Z is 0.1. The specimen height, diameter and thickness of the outer and inner steel pipes are the same as those of C2, and the cross section is also circular. The steel yield strength f of the specimen is y is 345MPa, the axial compressive strength of concrete is f cu The pressure is 33.1 MPa, and the geometric dimensions of the air domain are 410×600×2500 mm. This configuration is designed to compare the dynamic response characteristics of steel tube concrete columns with different TNT doses.

[0053] pass Figure 2The difference between the traditional APDL interface and the SpaceClaimPython interface is shown. The traditional APDL interface is designed in full English, and the operation interface is relatively complex. When users modify 3D models, they cannot directly operate the model and need to repeatedly click the menu and enter commands to achieve it. In contrast, the SpaceClaimPython interface is designed in full Chinese, with a clear interface layout and reasonable function classification, which helps to reduce the difficulty of learning and allows users to directly modify the 3D model. This design can significantly improve modeling efficiency and user experience.

[0054] pass Figure 3 The process of generating 3D models through script recording and automatic annotation in the Ansys SpaceClaimPython interface is demonstrated. A "Save Script" button is provided in the upper left corner of the interface to save the current modeling process at any time. The system automatically records the operation steps to generate the script, and automatically generates Chinese step annotations, which greatly facilitates the understanding and editing of the script; users can directly operate on the generated model and fine-tune the model through the "Model Micro-Repair Menu"; specific operations include setting basic parameters in positions such as "center coordinates" and "circle radius", and then running the script (shortcut key F5) to finally generate a cylindrical model. This process demonstrates the advantages of using Python scripts to quickly build models, and improves readability through Chinese annotations, which is suitable for seamless docking with the needs of Chinese users.

[0055] pass Figure 4 The schematic diagram of the high-fidelity numerical model of specimens C2 and C3 is shown, which mainly includes a three-layer structure of inner steel pipe, concrete and outer steel pipe. A SALE domain (air) is set around the model, and a non-reflecting boundary is added to simulate the actual air environment. In addition, SALE filler (explosive) is used to simulate the effect of explosion shock on the specimen. A rigid ground is also set in the figure, and a reflective boundary condition is applied to ensure the ground's reflection effect on the shock wave; specimens C2 and C3 respectively show different material mesh division methods. The structure and boundary conditions of the two are set the same, both including a three-layer structure of inner steel pipe, concrete and outer steel pipe, which is used to compare the dynamic response of different specimens under explosion loads.

[0056] pass Figure 5The residual displacement results and displacement-time curves of specimens C2 and C3 under test and numerical simulation are shown, reflecting the dynamic response and permanent deformation characteristics of the specimens under blast load. The residual displacement of specimen C2 measured by test is 29.3mm, and the residual displacement obtained by numerical simulation is 27.1mm, with local depression on the surface of the specimen; for specimen C3, the residual displacement measured by test is 77.7mm, and the residual displacement obtained by numerical simulation is 68.7mm, with more significant surface depression and larger deformation. There are certain errors between the experimental residual displacement and numerical simulation results of specimens C2 and C3, which are 2.2mm (about 7.5%) and 9mm (about 11.6%) respectively.

[0057] An efficient modeling method based on the SALE method to simulate the explosion resistance of steel tube concrete columns is proposed. By finely setting the air domain, explosive filling and rigid boundary conditions in the model, the air domain is treated with a non-reflecting boundary, thereby accurately simulating the dynamic response of steel tube concrete columns under explosion loads. The high consistency between the numerical simulation and the experimental results verifies the feasibility of this method, indicating that this modeling method has good applicability and reliability in the analysis of the explosion resistance of steel tube concrete columns, and can provide an effective reference for the explosion resistance design of actual engineering.

[0058] pass Figure 6 The dynamic cloud diagram of the pressure wave of the specimen C3 obtained by the modeling method of the present invention during the explosion of the explosive is shown. The figure shows the pressure distribution at four time points of 0.0ms, 0.006ms, 0.13ms and 0.26ms respectively. At 0.0ms, the explosive has not yet detonated, the pressure distribution is uniform, and the pressure value is close to zero; at 0.006ms, the high-pressure shock wave generated at the moment of the explosion propagates to the surroundings, and an obvious high-pressure area (red area) can be seen in the figure, and gradually spreads; by 0.13ms, the pressure wave has expanded outward and affected the surrounding medium area, the pressure has been reflected by the rigid ground, and the pressure gradually decays; at 0.26ms, the pressure wave continues to propagate, the range is further expanded, the pressure gradually decreases, and gradually transitions to a stable state.

[0059] The efficient modeling method for simulating the explosion resistance of steel tube concrete columns based on the SALE method successfully captures the dynamic evolution of pressure waves during explosions, and clearly shows the propagation path of shock waves and the law of pressure attenuation. This method can effectively simulate the dynamic response of steel tube concrete columns under explosion loads, and provides a reliable numerical analysis tool for explosion resistance design.

[0060] pass Figure 7The effective plastic strain distribution of specimens C2 and C3 under blast loads is shown, and the plastic strain of the outer steel pipe, concrete and inner steel pipe is analyzed to evaluate the damage characteristics of different components under impact loads. In the plastic strain cloud diagram of specimen C2, the plastic strain of the outer and inner steel pipes is low and concentrated in local areas, while the plastic strain of concrete covers a larger range, indicating that the concrete has been severely damaged under the blast load, and the outer layer structure has a more significant protective effect on the inner layer; in specimen C3, the strain distribution pattern of the outer and inner steel pipes is similar to that of specimen C2, but the overall plastic strain is larger, and the strain of the concrete part is almost distributed throughout the entire cross-sectional area, indicating that C3 has undergone significant deformation under a larger blast load, and the structural damage is more serious.

[0061] The present invention is an efficient modeling method for simulating the explosion resistance of steel tube concrete columns based on the SALE method, which successfully captures the plastic strain distribution characteristics of each component of the steel tube concrete column under explosion load. The results show that this method can effectively simulate the explosion resistance of steel tube concrete columns under different explosion load conditions, providing an accurate analysis basis for structural explosion resistance design.

[0062] The above description is only a specific embodiment of the present invention, and does not limit the patent protection scope of the present invention. Any use of this method to establish a numerical model of steel tube concrete and apply it to simulate problems in other related technical fields, such as structural explosion resistance performance evaluation, shock wave propagation analysis, etc., all fall within the protection scope of the present invention. Any improvement or deformation based on the method of the present invention, without departing from the core idea of ​​the present invention, should be regarded as the protection content of the present invention.

Claims

1. An efficient modeling method for simulating the explosion resistance of concrete-filled steel tube columns based on the SALE method, characterized in that: The following steps are involved: Step 1: Initialize the LS-DYNA module: Open the finite element analysis software ANSYS Workbench, select the LS-DYNA module, and initialize the engineering environment; Step 2: Define material parameters: In the engineering data module, define the material parameters of the steel pipe and concrete, including elastic modulus, density, Poisson's ratio and failure criterion, and define the material model and state equation of the explosive and air domain to ensure that the actual physical performance requirements are met; Step 3: Quickly build the model: Use the Python code command flow in SpaceClaim to quickly generate the geometric model and explosion load scenario required for simulation by simply inputting the key dimensions of steel tube concrete columns, explosives, and air; Step 4: Apply boundary conditions and loads: After loading the SpaceClaim geometry model in the Mechanical module, set the characteristic parameters of the explosion load based on the SALE method, divide the meshes for all entities, and add boundary conditions to ensure that the simulation scene truly restores the explosion situation; Step 5. Solution and calculation: Call the LS-RUN solver to solve and dynamically track the response process of the column structure to verify the accuracy of the simulation results.

2. The efficient modeling method for simulating the explosion resistance of concrete-filled steel tube columns based on the SALE method according to claim 1 is characterized in that: The specific process of step 2 is: Step 2-1, define the material model of concrete, input the corresponding value, and select the concrete material model for explosion analysis, including RHT model, MAT_14 model, MAT_25 model, MAT_96 model and MAT_72 model; RHT model is a material model used for dynamic response analysis of concrete under explosion load, which can accurately describe the yield, damage and fracture behavior of concrete under high strain rate, especially under the impact of explosion; MAT_14 model is a material model based on concrete damage, which can simulate the process of crack propagation of concrete under strong impact load, and is used to analyze concrete damage under explosion load; MAT_25 model is specially designed to simulate the destruction process of concrete under extremely high strain rate and explosion load, and can accurately capture the strength degradation and fracture behavior of concrete under these conditions; The MAT_96 model is suitable for simulating the concrete response under ultra-high strain rates, especially under the conditions of high dynamic loads of explosions, and provides accurate predictions for the stress-strain characteristics of concrete. The MAT_72 model is used to describe the thermodynamic behavior of concrete under explosion impact, and is suitable for analyses that need to consider temperature effects and blast wave propagation. Step 2-2, define the critical value of concrete failure criterion: Failure criterion is used to determine whether concrete is damaged. Usually, the failure mode of concrete under a specific load is determined by setting a critical value. In blast load analysis, failure criteria include Mohr-Coulomb criterion, Von Mises criterion and Johnson-Cook criterion. Mohr-Coulomb criterion is based on the relationship between shear stress and normal stress, and describes the failure behavior of concrete under tension and compression. The Von Mises criterion is used to describe the yield behavior under complex stress states and is suitable for the analysis of plastic materials. The Johnson-Cook criterion is suitable for material failure under high strain rate and high temperature conditions and can effectively simulate the destruction process under explosive impact loads. Critical stress refers to the stress value at which concrete begins to crack under a specific stress state, critical strain refers to the strain value at which macroscopic cracks begin to appear after the material reaches a certain degree of deformation, and critical energy is the maximum energy that the material can absorb under dynamic loading; Step 2-3: Define the strain rate effect of concrete; The dynamic amplification factor CDIF of concrete compressive strength is determined by the following formula: The dynamic amplification factor TDIF of concrete tensile strength is determined by the following formula: In the formula, f cd The strain rate of concrete is The corresponding dynamic compressive strength, f cs is the static compressive strength of concrete, f td The strain rate of concrete is The corresponding dynamic compressive strength, f ts is the static compressive strength of concrete, is the strain rate of concrete under blast load; Step 2-4: Repeat steps 2-1, 2-2, and 2-3 to establish the steel pipe, air, and explosive material models and their parameters in sequence, where the strain rate effect DIF of the steel material becomes: The strain rate of steel is The yield strength at y is the yield strength of steel, and parameters D and P are strain rate parameters Explosive material model: *MAT_HIGH_EXPLOSIVE_BURN combined with *EOS_JWL state equation is used to define the detonation characteristics of explosives; Air material model: Air is used as a fluid material, using *MAT_NULL combined with the EOS_LINEAR_POLYNOMIAL state equation, and the ideal gas model to control the dynamic response of the air; Material parameters that are not in the material library are forced to replace the default material parameters by entering the K file code through the Mechanical insert command.

3. The efficient modeling method for simulating the explosion resistance of concrete-filled steel tube columns based on the SALE method according to claim 1 is characterized in that: The specific process of step 3 is: Step 3-1: Initial model building; In SpaceClaim geometric modeling software, first enter the script panel and enable the Python script recording function; this will enable the software to automatically record operations and generate corresponding Python code during the modeling process; next, perform geometric modeling operations; first draw a circle on the canvas to represent the core area of ​​the concrete; use the "stretch" function to stretch the flat circle into a three-dimensional cylinder to create a three-dimensional model of the core concrete; by setting the diameter of the circle, the size of the concrete can be precisely controlled; this operation realizes the transformation from simple two-dimensional geometry to three-dimensional structure, forming a concrete base model; Step 3-2: Automatically generate Python code and save; When building a model, the script panel of SpaceClaim will automatically record each step of the operation and generate the corresponding Python code; by viewing the code in the script panel, you can understand and modify the generated modeling instructions, and add Chinese comments to facilitate subsequent operation understanding and backtracking; after completing the core concrete model, save the generated Python code and rename it to "core concrete", and regenerate or modify the model by running the script; Step 3-3: Repeat the modeling operation; Repeat steps 3-1 and 3-2 to build steel pipe, explosive and air models respectively. In each step, you need to create the steel pipe shell, explosive area and air layer according to the design requirements. Each step will automatically generate the corresponding Python code with Chinese comments. After each model part is completed, save the generated code and rename it to "steel pipe", "explosive" and "air" respectively to distinguish different model parts and ensure that the modeling process of each part is managed and called separately. Step 3-4: Batch modeling and parametric analysis When performing batch modeling and parametric analysis, you can modify the key parameters of each geometric body by importing different entity codes saved previously. After modifying the parameters, you can immediately run the code by pressing the shortcut key to generate a new 3D model. Step 3-5: Shared contact surface definition After completing the creation of each entity model, use the sharing function under the SpaceClaim toolbar to automatically identify the contact surfaces between different entities. With the help of the sharing function, there is no need to manually define the position and properties of each contact surface. SpaceClaim will automatically determine the relationship between the steel pipe and concrete and assign appropriate contact surfaces to them. This operation improves modeling efficiency and reduces human errors. Step 3-6: Open the Mechanical interface for subsequent analysis After successfully establishing the explosion model of the steel tube concrete column, open the Mechanical interface directly through SpaceClaim; at this time, SpaceClaim will automatically load the geometric model just created and import it into the Mechanical module; the Mechanical interface will provide a complete geometric model for subsequent finite element analysis, including the geometric information of steel tubes, concrete and other media; further material property settings, boundary condition definitions, meshing and loading condition configuration operations are performed in the Mechanical interface to provide necessary pre-processing support for explosion load simulation and structural response analysis.

4. The efficient modeling method for simulating the explosion resistance of concrete-filled steel tube columns based on the SALE method according to claim 1 is characterized in that: The specific process of step 4 is: Step 4-1: Material allocation; In the Mechanical interface, first assign the corresponding material model to each entity unit; according to the previously established geometry and the selected material model, specify the material properties of each entity in the Mechanical material assignment function; Step 4-2: Connection settings; In this step, insert Euler / Lagrangian coupling to deal with the interaction between different materials; select the steel tube concrete column as the Lagrangian part, representing the solid material part, the explosive as the SALE filler to simulate the transfer process of the explosion load, and the air part as the SALE domain to simulate the propagation of the explosion wave; the number of coupling points is set to 3, and during the calculation process, there are enough coupling nodes between the explosive and the steel tube concrete column and the air to transmit dynamic information; other parameters remain in the default settings to ensure that the basic coupling accuracy and stability are maintained during the simulation process; Step 4-3: Divide the grid; Meshing is a key step in numerical simulation. In the Mechanical interface, the unit mesh size can be adjusted based on different entity sizes without the help of external software. For steel tube concrete columns, the sweep method is selected for meshing. The method of sweeping from the top surface of the column to the base surface can achieve structured meshing and ensure the accuracy and stability of the calculation results. By evenly distributing the grid from the top to the bottom of the column, the errors that may be caused by irregular grids are avoided; for the explosive and air parts, since their shapes may be more complex, the grid division method is optimized according to the specific geometric shapes to improve the calculation efficiency and reduce the amount of calculation during simulation calculation; when performing grid division, it is necessary to pay attention to the fineness of the grid to ensure that the local area can have a sufficiently fine grid to capture the transient response under the action of the explosion load; Step 4-4: Add borders; After the model is established, the boundary condition setting stage begins. First, set the detonation point for the explosive area. The detonation point needs to be set at the appropriate position of the explosive to accurately simulate the occurrence of the explosion. Add a non-reflecting boundary surface in the air area to ensure that the air layer does not produce unnecessary reflection effects with other model parts during the simulation process, so that the propagation of the explosion wave can be simulated more realistically. For the steel tube concrete column, add fixed constraints to limit the freedom of its boundary to ensure that the bottom of the column is fixed, thereby simulating the boundary conditions of the actual structure. Avoid simulation errors caused by boundary conditions to ensure that the response of the steel tube concrete column conforms to the actual physical behavior during the entire explosion load process. Step 4-5: Calculation settings In the calculation setting stage, first enter the duration of the simulation calculation; Choose the appropriate simulation duration based on actual needs and the complexity of the simulation model; In order to accurately simulate the explosion process, the hourglass model is selected to deal with the numerical stability problem in the simulation; When setting up calculation output, determine the frequency of output results, including animation and curve output frequency, so as to track the simulation progress in real time and obtain dynamic response data; The choice of output frequency should be determined based on the accuracy requirements of the calculation and the limitations of computing resources; Step 4-6: Output file; Select the MAPDL input file option in the LS-DYNA module to export the simulation data into a format that can be used by the software for subsequent analysis; save the simulation results in the K file format, which contains the node data, material properties, mesh division, and boundary conditions of the structure; the generated K file is used for subsequent post-processing analysis or further simulation verification to provide detailed simulation data for engineering design.

5. The efficient modeling method for simulating the explosion resistance of concrete-filled steel tube columns based on the SALE method according to claim 1 is characterized in that: The specific process of step 5 is: Step 5-1: Call LS-RUN solver to solve K file First, use the LS-RUN solver to solve the K file generated by Workbench; enter the path of the K file and the location of the solver file; LS-RUN reads and starts the calculation; Step 5-2: Set up computer configuration According to the computer hardware configuration, set the number of CPU cores and memory size during solution; Step 5-3: Set solver parameters and start calculation Select precision in the LS-DYNA command menu, and then enter the solution command in the command line: $SOLVER i=$INPUTncpu=$NCPU memory=$MEMORY, where $INPUT is the K file path, $NCPU and $MEMORY are the set core number and memory size respectively; after setting, start the calculation; Step 5-4: View calculation results and perform post-processing After the calculation is completed, use LS-PrePost to open the calculation results for post-processing and view the simulation results; The deformation and stress distribution information of steel tube concrete columns under blast loads are analyzed to evaluate their explosion resistance.

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