Airport terminal anti-explosion evaluation method based on grid mapping and ALE

Abstract

The invention provides an airport terminal anti-explosion evaluation method based on grid mapping and ALE, and the method comprises the steps: S1, obtaining explosion working condition parameters and airport terminal structure data, S2, building an explosion model, initializing an ALE grid, and dynamically adjusting the size of the grid according to a self-adaptive mapping threshold value condition, S3, building a damage evolution model of an airport terminal based on the explosion model in S2, and S4, carrying out overall safety assessment on the terminal, and carrying out visual output on an assessment result. The method aims at solving the problems that in the prior art, terminal modeling and calculation time is long, occupied memory is large, cost is high, and rapid evaluation requirements are difficult to achieve, the action mechanism under the explosion action can be more accurately reproduced, explosives of any shape and equivalent can be controlled, and the explosive requirements under most of explosion working conditions are met.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of building structure safety, and particularly relates to a terminal blast resistance evaluation method based on mesh mapping and ALE. BACKGROUND

[0002] In recent years, airport terminals as large transportation hubs have significantly improved in construction scale and complexity. As an important part of the city's comprehensive transportation system, the construction of civil airport terminals plays a very important role in promoting local economic and social development. However, large civil airport terminals generally have characteristics such as large size, diverse functions, and complex personnel. The large size and through space also bring many difficulties and challenges to the blast resistance design of the building. Considering that airport terminal projects are generally large in size and complex in professional engineering, in order to achieve a free-form building shape, the roof is mostly made of large-span steel structure. Under the action of accidental events such as explosion, fire, or earthquake, the main load-bearing members may fail, and the structural collapse resistance directly relates to the safety of people's lives and property. Therefore, it is necessary to study the continuity collapse performance of large-span space structures under blast action.

[0003] Existing terminal-related specifications mostly focus on fire resistance design. For example, the American NFPA-409 "Standard for the Protection of Hangers" states that hangar doors need to meet the fire resistance limit requirements; explosion high-risk areas need to be provided with fireproof insulation boards; the European Union EN1991-1-7 stipulates that large-span structures of terminals need to consider the dynamic load distribution of blast shock waves; and the Chinese "Design of Civil Airport Terminal Fire Protection Code" GB 51236-2017 prohibits the use of liquefied petroleum gas in terminal buildings, and natural gas use areas need to be located near the outer wall and have good ventilation conditions to prevent the accumulation of flammable gases and cause explosions. However, these specifications provide very limited information on structural response under blast load, and do not provide specific design and safety evaluation methods.

[0004] With the continuous improvement of protective structure requirements and safety levels, as well as the continuous development of material science, terminals are facing the need for protection against potential threats such as terrorist attacks and explosions. Considering that conducting prototype tests is costly and dangerous, the finite element simulation method has become an economical and safe alternative. Therefore, a correct and efficient finite element simulation method can not only improve the safety and reliability of terminal blast resistance design, but also simulate various working conditions under real conditions and perform optimization design. In existing technologies, LS-DYNA is a finite element program suitable for simulating high-speed collision, explosion, and molding of structures with large deformation dynamic response problems. LS-DYNA shows better application scenarios in simulating blast conditions. However, there are still the following deficiencies in the research on terminal blast simulation methods:

[0005] (1) Traditional anti-explosion design relies on static empirical formula, which is difficult to deal with the coupling effect of explosion shock wave and dynamic structure response. The traditional ALE (Arbitrary Lagrange-Euler) algorithm adopts to establish a numerical analysis model of explosive and air and applies explosion load by means of state equation. However, this method occupies large memory and takes a long time to calculate.

[0006] (2) In the prior art, the traditional ALE method and the mesh mapping technology are usually used independently. The traditional ALE method is used for solving physical problems, and the mesh mapping is used for optimizing computing resources. There are obvious differences between the two in application scenarios and technical targets, which leads to the fact that the technical personnel in the field usually do not consider combining the two. For general explosion simulation mapping method, the accuracy and efficiency are better than ALE algorithm. Most scholars adopt ALE algorithm to accurately simulate the explosion process, but the calculation time is longer. The combination of mapping method and ALE algorithm is suitable for any explosion working condition, which can well simulate the explosion propagation process and greatly reduce the influence of computer hardware to improve the calculation efficiency.

[0007] (3) Most scholars focus on the anti-explosion performance of component test and numerical simulation, and there are few studies on the dynamic response of terminal under explosion action. There is a lack of quantitative analysis of structural dynamic response (such as shock wave propagation path and material damage evolution), and there is a lack of a fast and reliable evaluation method. SUMMARY

[0008] The purpose of the present application is to provide an airport terminal anti-explosion evaluation method based on mesh mapping and ALE, to solve the problem of long calculation time, large memory occupation, high cost and difficulty in realizing fast evaluation demand in the prior art.

[0009] The technical solution adopted by the present application is an airport terminal anti-explosion evaluation method based on mesh mapping and ALE, comprising the following steps:

[0010] Step S1, obtaining explosion working condition parameters and terminal structure data;

[0011] Step S2, establishing an explosion model based on S1 and initializing ALE mesh, and dynamically adjusting the size of the mesh according to the threshold condition of adaptive mapping;

[0012] Step S3, establishing a damage evolution model of the terminal based on the explosion model of S2;

[0013] Step S4, performing overall safety evaluation on the terminal and visualizing the evaluation results.

[0014] Further, the specific steps of S2 are as follows:

[0015] S21, constructing an explosion load model, including a one-dimensional explosion load model and a two-dimensional airport building explosion model;

[0016] S22, initializing the ALE mesh at the air domain-airport building coupling interface and setting the threshold conditions for adaptive mapping, including the mesh deformation threshold |J| and the cell aspect ratio threshold AS, as follows:

[0017] Mesh deformation threshold: the critical value of the Jacobian determinant calculated by the two-dimensional explosion model is used as the mesh deformation threshold |J|, and when |J|≤0.2, the mesh is forced to be reconstructed;

[0018]

[0019] S23, based on the threshold of S22, adjusting the size of the air domain mesh and the structure domain mesh by dynamically adjusting the coefficient γ, as follows:

[0020]

[0021] f=1+ne -λt sin(2πf0t)

[0022]

[0023] where g(·) represents the pressure gradient response function, represents the air domain pressure gradient field, h(·) represents the structure deformation coupling function, represents the structure displacement gradient, f represents the shock wave time-varying factor, n is the oscillation amplitude coefficient, with a value range of 0.3-0.5; λ is the attenuation coefficient, with a value range of 0.015-0.025; f0 represents the main frequency of the shock wave, with a unit of Hz, t represents time, sin represents the sine function, e represents the natural constant, min(·) represents the minimum value, and ε represents the strain value of the structure.

[0024] Further, the specific steps of constructing the explosion load model are as follows:

[0025] S21a, a one-dimensional explosion load model containing only air and explosives is established, an axisymmetric one-dimensional air domain is first established, explosives are set at the origin, air is defined and an air mesh is established, then explosives are added in a volume filling manner, and the parameters of the explosives are defined, and both air and explosives are finely meshed using ALE1D elements;

[0026] S21b, an ALE2D element is used to establish a two-dimensional airport building explosion model, a mapping coordinate is defined, the boundary condition is set to a symmetric boundary, and a non-reflecting boundary condition is set at the right boundary of the model.

[0027] Further, the S3, the specific steps of establishing the damage evolution model of the terminal building are as follows:

[0028] S31, inputting the two-dimensional terminal building explosion model established in S2 into LS-DYNA software for simulation, and preliminarily determining the damage index of the terminal building;

[0029] S32, establishing a damage evolution model of the terminal building structure column, and the formula is as follows:

[0030]

[0031] Wherein, D c represents the damage index of the column, E p represents the cumulative plastic deformation energy, E p，crit represents the critical plastic deformation energy, σ represents the stress tensor, ε p represents the plastic strain increment, E p0 represents the critical plastic deformation energy under quasi-static state, represents the strain rate, represents the reference strain rate, and k represents the material strain rate sensitivity coefficient;

[0032] S33, establishing a damage evolution model of the glass curtain wall structure, and the formula is as follows:

[0033]

[0034] Wherein, D g represents the damage index of the glass curtain wall, σ eq represents the equivalent stress, σ crit represents the dynamic critical stress, which is related to the stress rate, σ0 represents the quasi-static fracture strength, represents the current stress rate, the reference stress rate, and α and β are material parameters, α is used to quantify the overall sensitivity of the glass curtain wall strength to the increase of strain rate, and β is used to quantify the nonlinearity of the sensitivity of the glass curtain wall strength to the strain rate, represents the damage rate, which starts to accumulate when the stress exceeds a certain proportion of the critical stress, is the cumulative damage of the glass curtain wall, and max(·) is the maximum value function, and t is the time.

[0035] Further, the safety evaluation is based on the damage index of the terminal building obtained in S3, and the real-time evaluation of the overall safety state of the terminal building is carried out, and the specific steps are as follows:

[0036] When the maximum value of all component damage indexes is less than 0.8, the terminal building is in a safe state;

[0037] When there is glass curtain wall damage Dg ≥0.80, and all column damage D c When the value is less than 0.90, the terminal building is under alert.

[0038] When column damage 0.90 ≤ D c The terminal building is in a dangerous condition when the total damage to all glass curtain walls is less than 0.95 or the total damage to all glass curtain walls is greater than or equal to 3.00.

[0039] When column damage D c When the value is ≥0.95, the terminal building is in a state of failure.

[0040] Furthermore, the visualization output is a two-dimensional damage heatmap generated from the safety status assessment, using different colors to represent the degree of damage to the terminal building, as detailed below:

[0041] Orange indicates that 0.6 ≤ D c <0.9 indicates damage to the column structure in this area;

[0042] Yellow indicates 0.5 ≤ D g <0.8 indicates damage to the glass curtain wall in this area;

[0043] The red area indicates the damaged part of the terminal building, D. c ≥0.9 or D g ≥0.8 indicates column structure failure or glass curtain wall rupture in this area;

[0044] Green indicates a safe zone.

[0045] The beneficial effects of this invention are:

[0046] 1. Compared with prototype and scaled-down structure explosion resistance tests, this invention is more efficient, can study more working conditions, analyze more detailed data, is more reliable, and has lower cost. It is also not limited by site or personnel and is safer.

[0047] 2. The multi-scale mesh mapping technology established in this invention has high reliability and applicability. Traditional blast-resistant design often relies on static empirical formulas, which are difficult to cope with the coupling effect of blast shock waves and dynamic structural responses. Although the application method is simple and the calculation time is short, it lacks quantitative analysis of the dynamic response of the structure (such as the shock wave propagation path and material damage evolution). In contrast, this invention considers the blast wave propagation process and the process of the wave acting on the structure, which can more accurately reproduce the action mechanism under the blast. It can also control explosives of arbitrary shape and yield, meeting the explosive requirements under most blast conditions.

[0048] 3、The application is based on a large number of empirical formulas obtained from previous explosion tests as data basis, and through mapping method and traditional ALE method, an airport building explosion model is established for comparison, the application significantly improves the efficiency and accuracy of the airport building explosion evaluation, and can quickly evaluate the dynamic response of the airport building under the explosion action through the damage index. BRIEF DESCRIPTION OF DRAWINGS

[0049] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0050] Figure 1 is a flowchart of the present application.

[0051] Figure 2 is a one-dimensional explosion model diagram of free air explosion.

[0052] Figure 3 is a schematic diagram of the volume filling method of explosion load application.

[0053] Figure 4 is a two-dimensional explosion model diagram of free air explosion.

[0054] Figure 5 is an explosion wave acting on the structure pressure cloud diagram.

[0055] Figure 6 is a thermal diagram of part of the glass curtain wall and the structure column.

[0056] Figure 7 is a comparison diagram of the empirical formula and the numerical simulation result under the mapping method.

[0057] Figure 8 is a time comparison diagram of the mapping method and the traditional ALE method.

[0058] Figure 9 is a comparison diagram of the empirical formula and the numerical results of the mapping method and the traditional ALE method.

[0059] Figure 10 is a comparison diagram of the airport building explosion simulation results under different methods. DETAILED DESCRIPTION

[0060] With reference to the accompanying drawings, the technical solutions in the embodiments of the present application will be described clearly and completely. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort are within the protection scope of the present application.

[0061] Embodiment

[0062] The embodiment of the present application provides a terminal building blast resistance evaluation method based on mesh mapping and ALE, and a flow chart is shown in Figure 1 The steps include:

[0063] In step S1, explosion condition parameters and terminal building structure data are obtained, the condition parameters include explosive charge and explosion position, and the terminal building structure data includes geometric dimensions of glass curtain wall and column, material properties of the two structures, and component connection information.

[0064] In step S2, based on the condition parameters and terminal building structure data in S1, a one-dimensional and two-dimensional explosion model is established through mesh mapping and ALE algorithm, and ALE mesh is initialized, and the size of the mesh is dynamically adjusted according to the threshold condition of adaptive mapping, and the specific steps are as follows:

[0065] In S21, an air domain model of explosion shock wave propagation and a terminal building model are constructed, and the specific steps are as follows:

[0066] In S21a, a one-dimensional explosion load model containing only air and explosive is established, an axisymmetric one-dimensional air domain is established by using HyperMesh software, as shown in Figure 2 The explosion point is defined by using the keyword *INITIAL_DETONATION, the flow chart of establishing the explosion load model is shown in Figure 3 Firstly, the air is defined by using the keywords *MAT_NULL and *EOS_LINEAR_POLYNOMIAL state equation, and the air mesh is established, then the explosive is added in the form of volume filling by using the keyword *INITIAL VOLUME FRACTION GEOMETRY, so that the explosive is defined in the air mesh in the form of filling material, and then the *MAT-HIGH-EXPLOSIVE-BURN model is used to define the shape, position and other parameters of the explosive in cooperation with the JWL state equation. The one-dimensional model is shown in Figure 2 The air and explosive are both finely meshed by using ALE1D (*SECTION_ALE1D) unit, and the mesh size can be set according to requirements, and in the embodiment, the mesh is divided into 10mm.

[0067] This stage focuses on the initiation process simulation of explosives, aiming to lay a good foundation for the subsequent mapping analysis of explosion load, and accurately capture the initial characteristics of energy release and propagation at the moment of initiation.

[0068] S21b, a two-dimensional explosion model is established by using ALE2D (*SECTION_ALE2D) unit, as shown in Figure 4 The initiation point does not need to be set again in this stage, only the mapping coordinates need to be defined to make the explosion wave propagate in the air. The initiation point is defined by the keyword *INITIAL_DETONATION, the boundary condition is set to symmetric boundary, and the non-reflecting boundary condition is set on the right boundary of the model by the keyword *BOUNDARY_NON_REFLECTING to eliminate the reflection effect of the shock wave. The air and explosive parameters are consistent with those in S21a, and the one-dimensional explosion load model of S21a is imported into the two-dimensional explosion model. The mesh division of the two-dimensional explosion model does not need to be as fine as that of S21a, and generally within 10 times of the one-dimensional explosion model, such as 50mm. Since the explosion has been initiated, the initiation and position of the explosive do not need to be defined. Compared with the traditional method of directly establishing a two-dimensional model, the present application can better ensure the accuracy of the calculation, the model size and mesh division requirements are more precise than the traditional method, the memory occupation is smaller, and the calculation efficiency is higher.

[0069] In the two-dimensional air domain model, the geometric characteristics of the terminal are modeled, mainly including the key column and curtain wall parts. These areas first bear the direct action of the shock wave when the explosion occurs, and the stress is the most complex and intense. The steel column and glass curtain wall are divided into rectangular sections by 2D mesh, such as 5mm, and the material parameters are determined. The mesh nodes are simulated by BAR2 rigid elements with additional rotational stiffness constraints. The boundary condition is set to be fixed to all degrees of freedom, simulating the rigid support of the foundation. The bottom of the steel column is defined as hinged or fixed according to the actual structure design to reflect the true constraint condition of the bottom of the steel column. The outer edge of the air domain is set to a non-reflecting boundary condition to eliminate the reflection interference of the shock wave at the boundary of the air domain and ensure the authenticity of the explosion wave propagation. The rest is processed according to the public node, and then the MAP file of the one-dimensional model is imported into the two-dimensional model. This operation is realized by calling *INITIAL-ALE-MAPPING. The pressure cloud diagram of the explosion wave action is shown in Figure 5 .

[0070] S22, initialize the ALE mesh at the air domain-terminal coupling interface, and set the threshold conditions for adaptive mapping, including the mesh deformation threshold |J| and the aspect ratio threshold AS of the element, as follows:

[0071] Grid deformation threshold: the critical value of the Jacobian determinant calculated by the two-dimensional explosion model is used as the grid deformation threshold |J|, when |J|≤0.2, the grid is forced to be reconstructed;

[0072]

[0073] S23, based on the threshold of S22, dynamically adjust the size of the air domain grid and the structure domain grid, in the application, the airport column and the curtain wall structure adopt Lagrange grid, the air domain is set as ALE grid, through the existing fluid-solid coupling, the process of explosion wave propagation in the air domain and interaction with the airport is realized, at the same time, the adaptive mapping algorithm is adopted to track the deformation of the coupling interface between the air domain and the airport in real time, and the grid deformation data is obtained in real time, when the interface grid distortion exceeds the grid deformation threshold or the unit length-width ratio threshold, the adaptive mapping mechanism is triggered, the size of the air domain grid and the structure domain grid is adjusted through the dynamic adjustment coefficient γ, the formula is as follows:

[0074]

[0075] f=1+ne -λt sin(2πf0t)

[0076]

[0077] Wherein, g(·) represents the pressure gradient response function, ▽P represents the air domain pressure gradient field, h(·) represents the structure deformation coupling function, represents the structure displacement gradient, f represents the shock wave time-varying factor, n is the oscillation amplitude coefficient, the value range is 0.3-0.5; λ is the attenuation coefficient, the value range is 0.015-0.025; f0 represents the main frequency of the shock wave, unit Hz, t represents time, sin represents the sine function, e represents the natural constant, min(·) represents the minimum value, and ε represents the strain value of the structure.

[0078] Step S3, based on the explosion model of S2, the damage evolution model of the airport is established through numerical simulation. Through the output dynamic response and the setting of damage grade, the airport explosion is quickly evaluated, only the airport geometric parameters, explosive equivalent and blast center distance need to be input, then the explosion load and the dynamic response of the airport under the action of the explosion caused earthquake can be output. The specific steps are as follows:

[0079] S31, input the two-dimensional explosion model established in S2 into LS-DYNA software for simulation, and preliminarily determine the damage index of the airport.

[0080] S32, establish the damage evolution model of the terminal building structure column, determine the critical plastic deformation energy of the structure column by accumulating damage and improving the Johnson-Cook constitutive equation, so as to determine the damage index of the structure column, and the formula is as follows:

[0081]

[0082] Wherein, D c represents the damage index of the column, 0 c ≤0.60, the concrete protective layer peels off, 0.60 c ≤0.90, the concrete appears a large number of cracks, 0.90 c ≤1.00, the structure column is seriously damaged, and the column body fails; E p represents the accumulated plastic deformation energy, E p，crit represents the critical plastic deformation energy, σ represents the stress tensor, and ε p represents the plastic strain increment, E p0 represents the critical plastic deformation energy under quasi-static state, represents the strain rate, represents the reference strain rate, and k represents the material strain rate sensitivity coefficient.

[0083] S33, establish the damage evolution model of the terminal building glass curtain wall structure, based on the particularity of the terminal building, combine the shock wave theory, and improve the Power-Law type strain rate model through numerical simulation, so as to determine the damage index of the glass curtain wall, and the formula is as follows:

[0084]

[0085] Wherein, D g represents the damage index of the glass curtain wall, 0 g ≤0.5, visible cracks appear, 0.50 g ≤0.80, the glass is broken, 0.80 g ≤1.00, the glass curtain wall is seriously damaged, and the fragments splash; σ eq represents the equivalent stress, σ crit represents the dynamic critical stress, which is related to the stress rate, σ0 represents the quasi-static fracture strength, represents the current stress rate, the reference stress rate (usually 1.00 MPa / s), and α and β are material parameters, α is used to quantify the overall sensitivity of the glass curtain wall strength to the increase of strain rate, and β is used to quantify the nonlinear degree of the sensitivity of the glass curtain wall strength to the strain rate, represents the damage rate, when the stress exceeds a certain proportion of the critical stress, the accumulation begins, is the cumulative damage of glass curtain wall, max(·) is the maximum value function, and t is time.

[0086] S4, based on the terminal damage index obtained in S3, the overall safety of the terminal is evaluated, and the evaluation result is visualized and output, and the specific steps are as follows:

[0087] S41, the overall safety state of the terminal is evaluated in real time, and different results can be output according to different explosion action times. Evaluation criteria: when the maximum value of all component damage indexes is less than 0.8, the terminal is in a safe state; when the damage of glass curtain wall D g ≥0.80, and the damage of all columns D c <0.90, the terminal is in an alert state; when the column damage 0.90≤D c <0.95 or all glass curtain wall cumulative damage ≥3.00, the terminal is in a dangerous state; when the column damage D c ≥0.95, the terminal is in a failure state.

[0088] S42, the overall safety state of the terminal is visualized and output, and a two-dimensional damage thermal map is generated, as shown in Figure 6 , orange represents 0.6≤D c <0.9, the column structure in this area appears damage, such as concrete protective layer peeling; yellow represents 0.5≤D g <0.8, the glass curtain wall in this area appears damage, such as cracks; red represents the damaged area of the terminal, D c ≥0.9 or D g ≥0.8, the column structure in this area fails or the glass curtain wall breaks; green represents a safe area.

[0089] The output result of the terminal damage evolution model of the application is the damage condition of the structural column and the glass curtain wall, the terminal damage evolution model can quantitatively evaluate the damage characteristics of the material, capture the damage accumulation process, provide a basis for the design of the terminal, through the established explosion model, a large number of working condition analysis can be carried out, the anti-explosion performance of the terminal under different explosion conditions can be quickly evaluated, and through the visualized way, the safety state of the terminal can be more directly observed.

[0090] Experimental verification

[0091] The load of the model is verified by using the mapping method and the traditional ALE algorithm respectively, and the verification range is proportional distance 1.8-6m / kg 1 / 3The present application firstly establishes a one-dimensional explosion model, and exports the obtained result through a MAP file; then a two-dimensional model is established, and the exported MAP file is imported into the two-dimensional model to realize the mapping of the explosion load. The traditional ALE algorithm directly establishes a two-dimensional model, and compares and analyzes the simulated load result with an empirical formula, and the result is shown in Figure 7 The error of the mapping method of the present application is within 15%, which illustrates the accuracy and reliability of the explosion load application, and the running time of the traditional ALE algorithm is compared, and the result is shown in Figure 8 The calculation time of the mapping method of the present application is only half of that of the traditional ALE algorithm.

[0092] The explosion model is that the air domain size is 100m*100m, and the explosive equivalent is 50kg. The mapping method is that firstly, a one-dimensional explosion model is established, and the size is divided into 10mm, which is to simulate the explosion initiation process, and the obtained result is exported through a MAP file; then a two-dimensional model is established, and the size is divided into 50mm, and the exported MAP file is imported into the two-dimensional model to realize the mapping of the explosion load. The traditional ALE method is that the same two-dimensional model grid size as the mapping is established, and the grid size is 25mm, and the explosive needs to be added through the keyword *INITIAL_VOLUME_FRACTION_GEOMETRY, and the air and TNT adopt the ALE2D algorithm, and the grid size needs to be more fine than that of the mapping method, otherwise it is difficult to guarantee the precision of the explosion load. The traditional ALE method takes 4.5h, while the mapping method takes 4min in the first step, and takes 116min in the second step, and the total time is 2h, as shown in Figure 9 By comparing the peak overpressure curves obtained by the traditional ALE method and the mapping method, the overpressure curves of the above two methods are better matched with the simulation curve and the measured curve compared with the empirical equation, and the mapping method is less than the measured value because of the difference in grid size between the one-dimensional model and the two-dimensional model in the mapping process, but the error is less than 15%, which illustrates that the numerical model and the related parameters of the mapping method can better simulate the explosion load. The damage of the output terminal building part glass curtain wall and the structure column is compared, and the result is shown in Figure 10 It can be observed that the damage comparison results are basically consistent, which illustrates that the mapping method is consistent in precision compared with the traditional ALE algorithm, which can greatly improve the calculation efficiency.

[0093] Each embodiment in the specification is described in a related manner, and the same and similar parts between each embodiment can be referred to each other, and each embodiment mainly illustrates the difference from other embodiments. Especially, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the related parts can be referred to the part of the method embodiment.

[0094] The above merely provides the preferred embodiments of the application, and not intended to limit the protection scope of the application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the application shall fall within the protection scope of the application.

Claims

1. A method for terminal blast resistance assessment based on mesh mapping and ALE, characterized by the steps of The method comprises the following steps: Step S1, obtaining explosion working condition parameters and terminal building structure data; Step S2, establishing an explosion model based on S1 and initializing an ALE grid, and dynamically adjusting the size of the grid according to the threshold condition of adaptive mapping; Step S3, based on the explosion model of S2, establishing a damage evolution model of the terminal building; Step S4, overall safety assessment of the terminal building, and visual output of the evaluation results.

2. The method for airport blast resistance evaluation based on mesh mapping and ALE according to claim 1, wherein, The specific steps of S2 are as follows: S21, constructing an explosion load model, including a one-dimensional explosion load model and a two-dimensional terminal building explosion model; S22, initializing the ALE grid at the air domain-terminal building coupling interface, and setting the threshold condition of adaptive mapping, including the grid deformation threshold |J| and the element aspect ratio threshold AS, which are as follows: Grid deformation threshold: the critical value of the Jacobian determinant calculated by the two-dimensional explosion model is used as the grid deformation threshold |J|, and when |J|≤0.2, the grid is forced to be reconstructed; Cell aspect ratio threshold: AS > 10 triggers grid optimization; S23, based on the threshold of S22, adjust the size of the air domain grid and the structure domain grid through the dynamic adjustment coefficient γ, the formula is as follows: f = 1 + ne -λt sin(2πf0t) where g(·) represents the pressure gradient response function, represents the air domain pressure gradient field, h(·) represents the structural deformation coupling function, represents the structural displacement gradient, f represents the shock wave time-varying factor, n is the oscillation amplitude coefficient, the value range is 0.3-0.5; λ is the attenuation coefficient, the value range is 0.015-0.025; f0represents the main frequency of the shock wave, the unit is Hz, t represents the time, sin represents the sine function, e represents the natural constant, min(·) represents the minimum value, and ε represents the strain value of the structure.

3. The method of airport blast resistance evaluation based on mesh mapping and ALE according to claim 2, characterized in that, The specific steps of constructing the explosion load model are as follows: S21a, a one-dimensional explosion load model containing only air and explosives is established, an axisymmetric one-dimensional air domain is first established, explosives are set at the origin, air is defined and an air grid is established, then explosives are added in a volume filling manner, and the parameters of the explosives are defined, and air and explosives are finely meshed by ALE1D elements; S21b, a two-dimensional terminal building explosion model is established by using ALE2D elements, the mapping coordinates are defined, the boundary conditions are set as symmetric boundary, and the non-reflecting boundary condition is set at the right boundary of the model.

4. The method of airport blast resistance evaluation based on mesh mapping and ALE of claim 1, wherein, In S3, the specific steps of establishing the damage evolution model of the terminal building are as follows: S31, inputting the two-dimensional terminal building explosion model established in S2 into LS-DYNA software for simulation to preliminarily determine the damage index of the terminal building; S32, establishing a damage evolution model of the terminal building structure column, the formula is as follows: E p = ∫σ dε p where D c represents the damage index of the column, E p represents the cumulative plastic deformation energy, E p，crit represents the critical plastic deformation energy, σ represents the stress tensor, ε p represents the plastic strain increment, E p0 represents the critical plastic deformation energy under quasi-static state, represents the strain rate, represents the reference strain rate, k represents the material strain rate sensitivity coefficient; S33, establishing a damage evolution model of the glass curtain wall structure, the formula is as follows: where D g represents the damage index of the glass curtain wall, σ eq represents the equivalent stress, σ crit represents the dynamic critical stress, σ0represents the quasi-static fracture strength, represents the current stress rate, the reference stress rate, and α and β are material parameters, α is used to quantify the overall sensitivity of the glass curtain wall strength to the increase of the strain rate, and β is used to quantify the nonlinearity of the strain rate sensitivity of the glass curtain wall strength, represents the damage rate, is the cumulative damage of the glass curtain wall, and max(·) is the maximum function, and t is the time.

5. The method of airport blast resistance evaluation based on mesh mapping and ALE of claim 1, wherein, The safety assessment is based on the terminal building damage index obtained in S3, which is a real-time evaluation of the overall safety state of the terminal building, and the specific steps are as follows: When the maximum value of all component damage indexes is <0.8, the terminal building is in a safe state; When there is a glass curtain wall damage D g ≥ 0.80, and all column damage D c < 0.90, the terminal is in an alert state; When column damage is 0.90 ≤ D c When column damage is 0.90 ≤ D c When column damage is 0.90 ≤ D c When column damage is 0.90 ≤ D c When column damage is 0.90 ≤ D c When column damage is 0.90 When the column is damaged D c When D ≥ 0.95, the terminal is in a failure state.

6. The method of airport blast resistance evaluation based on mesh mapping and ALE of claim 1, wherein, The visual output is a two-dimensional damage thermal map generated by the safety state evaluation, which represents the damage degree of the terminal building by different colors, and the specific steps are as follows: Orange 0.6 < D < 0.8 c <0.9, the column structure in this area is damaged; Yellow indicates 0.5 < D < 1.0 g <0.8, in this area the glass curtain wall is damaged; Red indicates areas of the terminal that are destroyed, D c ≥ 0.9 or D g ≥ 0.8, this area the column structure fails or the glass curtain wall breaks; Green represents a safe area.

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