A method for lightweight design of cylindrical charge for damaging reinforced concrete column

Abstract

The application discloses a column charge lightweight design method for damaging reinforced concrete columns, which comprises the following steps: step 1, setting the structure characteristic parameters and bearing characteristic parameters of the reinforced concrete column to be struck; step 2, selecting a charge type, determining charge material model parameters, giving a charge striking precision and an initiation mode; step 3, setting a column charge design constraint condition; step 4, according to the column charge constraint condition, batch generating column charge parameters meeting the constraint condition requirements, according to the different constraint condition setting modes in step 3, the column charge parameter batch generation methods are different; step 5, carrying out charge lightweight design simulation; and step 6, counting the simulation results and screening out the charge lightweight design results. The application realizes the customized design of small charge structures according to the column damage state, and can give the lightweight design results meeting the damage requirements under a series of charge size design constraint conditions.

Description

[0001] The application belongs to the technical field of damage, and particularly relates to a lightweight design method of a blasting charge, in particular to a cylindrical charge lightweight design method for damaging a reinforced concrete column. BACKGROUND

[0002] The reinforced concrete column is a core load-bearing component of a building target, and effective damage to multiple reinforced concrete columns in a building system can cause the building to collapse. With the development of small-sized cluster unmanned platforms, using a'swarm' to attack reinforced concrete columns to induce the overall collapse of a building is a potential effective damage method for the cluster platforms to attack buildings.

[0003] After investigation, the current small-sized cluster unmanned platform can only carry a kilogram-level effective load, but the reinforced concrete column is a typical solid target, and small charges can only produce certain damage effects on the reinforced concrete column when the distance is close. Considering the load requirement and endurance requirement of the cluster platform, the shape of the charge should be reasonably designed, and the damage capacity of the charge to the reinforced concrete column should be fully controlled to adapt to the small-sized and lightweight design requirements of the charge. At present, there is no lightweight design method of a blasting charge for supporting the damage of a reinforced concrete column. SUMMARY

[0004] In order to overcome the problem of lack of lightweight design of small charges in the prior art, the application provides a cylindrical charge lightweight design method for damaging a reinforced concrete column, which can customize and lightweight design a cylindrical blasting charge meeting the damage requirement according to the structural characteristics and bearing characteristics of a specific reinforced concrete column.

[0005] In order to achieve the above task, the application adopts the following technical solutions:

[0006] A cylindrical charge lightweight design method for damaging a reinforced concrete column comprises the following steps:

[0007] Step 1: setting structural characteristic parameters and bearing characteristic parameters of a reinforced concrete column to be attacked;

[0008] Step 2: selecting a charge type, determining a charge material model parameter, and giving a charge attack precision and a detonation mode;

[0009] Step 3: setting a cylindrical charge design constraint condition, and the parameters of the constraint condition can include a charge length L, a charge diameter D, a charge length-diameter ratio LDR and a charge mass M;

[0010] Step 4: generating a cylindrical charge parameter meeting the constraint condition requirement in batches according to the cylindrical charge constraint condition, and the cylindrical charge parameter batch generation method is different according to the different constraint condition setting modes in step 3;

[0011] Step 5: carry out charge lightweight design simulation, including the following steps:

[0012] Step 5.1: select an optional set of cylindrical charge parameters in step 4;

[0013] Step 5.2: establish a numerical simulation model of pre-axial compression of the reinforced concrete column by LS-DYNA preprocessing; the components in the model should include the reinforced concrete column, the axial compression loading rod and the gasket;

[0014] Step 5.3: according to the axial static load of the reinforced concrete column, a constant axial compression is applied to the reinforced concrete column until the internal force of the structure is balanced;

[0015] Step 5.4: on the basis of the simulation results in step 5.2, carry out a full restart analysis, and add air and explosive components;

[0016] Step 5.5: detonate the explosive charge, continuously observe the damage state of the reinforced concrete column, judge whether the reinforced concrete column is crushed or not, and record the simulation results, including "the column is crushed" or "the column is not crushed";

[0017] Wherein, the simulation result of "the column is crushed" refers to the axial instability of the column under the simultaneous action of axial compression and explosive load; the simulation result of "the column is not crushed" refers to the axial stability of the column under the simultaneous action of axial compression and explosive load;

[0018] Step 5.6: judge whether all the cylindrical charge parameters in step 4 have been traversed or not; if they have been completely traversed, end step 5; if they have not been completely traversed, return to step 5.1;

[0019] Step 6: count the simulation results, and select the lightest charge in the "column is crushed" working condition as the lightweight design result.

[0020] The cylindrical charge lightweight design method for damaging the reinforced concrete column of the present application has the following technical effects:

[0021] The present application realizes the customized design of small charge structure according to the column damage state ("the column is crushed" or "the column is not crushed"), can give the lightweight design result meeting the damage demand under a series of charge size design constraints, and further effectively reduces the charge mass redundancy for damaging the reinforced concrete column, improves the charge damage energy utilization rate, and the present application can support the development of small warhead for building damage. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is the flow chart of the cylindrical charge lightweight design method for damaging the reinforced concrete column of the present application;

[0023] Figure 2 is a schematic diagram of a numerical simulation model of a reinforced concrete column with pre-axial compression in the embodiment;

[0024] Figure 3 is a structural axial stress distribution diagram at the initial moment and after 50 ms of pre-axial compression in the embodiment;

[0025] Figure 4 is a diagram of the change trend of the mid-span axial compression of the structure over time during the pre-axial compression process in the embodiment;

[0026] Figure 5 is a schematic diagram of the simulation model after adding air and explosives after full restart analysis in the embodiment;

[0027] Figure 6 is a simulation result diagram of three charging parameter working conditions in the embodiment, where (a) is 1 kg, not crushed, (b) is 1.2 kg, not crushed, and (c) is 1.4 kg, crushed; DETAILED DESCRIPTION

[0028] The present application will be further described in conjunction with the preferred embodiments and the accompanying drawings.

[0029] As shown in Figure 1 , the columnar charge lightweight design method for damaging reinforced concrete columns provided by the present application comprises the following steps:

[0030] Step 1: Set the structural characteristic parameters and load-bearing characteristic parameters of the reinforced concrete column to be struck;

[0031] The structural characteristic parameters of the reinforced concrete column include length, width, height, longitudinal reinforcement diameter, longitudinal reinforcement quantity, stirrup diameter, stirrup spacing, cladding layer thickness, concrete uniaxial compressive strength, and steel yield strength;

[0032] The load-bearing characteristic parameter of the reinforced concrete column refers to its axial static load;

[0033] Step 2: Select the charge type, determine the charge material model parameter, and give the charge striking accuracy and initiation mode;

[0034] Step 3: Set the columnar charge design constraint conditions, the parameters of which can be set include charge length L, charge diameter D, charge length-diameter ratio LDR, and charge mass M, and the ways of which can be set include the following two:

[0035] Method 1: Set the range of charge length L and charge diameter D as design constraint conditions at the same time.

[0036] Charge length constraint condition: L min ≤L≤L max , where L min , L maxLmin and Lmax are minimum and maximum values of the charge length, respectively;

[0037] Dmin and Dmax are minimum and maximum values of the charge diameter, respectively; min ≤D≤D max , wherein D min , D max are minimum and maximum values of the charge diameter, respectively;

[0038] Method 2: Set the range of the charge length-diameter ratio LDR and the charge mass M as design constraints at the same time.

[0039] LDRmin and LDRmax are minimum and maximum values of the charge length-diameter ratio, respectively; min ≤LDR≤LDR max , wherein LDR min , LDR max are minimum and maximum values of the charge length-diameter ratio, respectively;

[0040] Mmin and Mmax are minimum and maximum values of the charge mass, respectively; min ≤M≤M max , wherein M min , M max are minimum and maximum values of the charge mass, respectively;

[0041] Step 4: According to the cylindrical charge constraint conditions, batch generate cylindrical charge parameters that meet the constraint condition requirements. According to the different constraint condition setting methods in step 3, the batch generation method of cylindrical charge parameters is different:

[0042] For method 1, according to the charge length constraint condition L min ≤L≤L max and the charge diameter constraint condition D min ≤D≤D max , respectively, m charge length samples L1, L2, L3, …, Li and n charge diameter samples D1, D2, D3, …, Dj are defined and generated, respectively, wherein 1≤i≤m, 1≤j≤n; m n

[0043]

[0044] Then, the parameters in the charge length samples and the charge diameter samples are combined in any way to form m×n groups of cylindrical charge size parameters (L i , D j ), wherein 1≤i≤m, 1≤j≤n;

[0045] For method 2, according to the charge length-diameter ratio constraint condition LDR min ≤LDR≤LDR max and the charge mass constraint condition M min ≤M≤M max ​​m charge length-diameter ratio samples LDR1, LDR2, LDR3, …, LDRm and n charge mass samples M1, M2, M3, …, Mn are respectively defined and generated m n The samples should satisfy:

[0046]

[0047] Then, parameters in the charge length-diameter ratio samples and the charge mass samples are combined in any way to form m x n groups of cylindrical charge parameters (LDRi,j i , Mi, j j ), where 1≤i≤m, 1≤j≤n, and further, the charge diameter D and the charge length L can be calculated according to the cylindrical charge parameters (LDRi,j i , Mi, j j ):

[0048]

[0049] Step 5: Perform charge lightweight design simulation, including the following steps:

[0050] Step 5.1: Select one group of cylindrical charge parameters in step 4;

[0051] Step 5.2: Establish a numerical simulation model of the pre-axial compression of the reinforced concrete column through LS-DYNA preprocessing; the components in the model should include the reinforced concrete column, the axial compression loading rod, and the gasket;

[0052] Step 5.3: According to the axial static load of the reinforced concrete column, apply constant axial compression to the reinforced concrete column until the internal force of the structure is balanced;

[0053] Step 5.4: Based on the simulation results of step 5.3, perform a full restart analysis and add air and explosive components;

[0054] Step 5.5: Initiate the explosive charge, continuously observe the damage state of the reinforced concrete column, determine whether the reinforced concrete column is crushed, and record the simulation results, which include “the column is crushed” or “the column is not crushed”;

[0055] The simulation result of “the column is crushed” refers to the axial instability of the column under the simultaneous action of axial compression and explosive load; the simulation result of “the column is not crushed” refers to the axial stability of the column under the simultaneous action of axial compression and explosive load.

[0056] Step 5.6: Determine whether all cylindrical charge parameters in step 4 have been traversed; if they have been completely traversed, end step 5; if they have not been completely traversed, return to step 5.1;

[0057] ​Step 6: Statistics simulation results, and screen out the charge lightweight design results, select the minimum weight of the charge in the "column is crushed" working condition as the lightweight design result.

[0058] The application is further described below through specific examples.

[0059] Example 1:

[0060] Step 1: Set the structural characteristic parameters and bearing characteristic parameters of the struck reinforced concrete column;

[0061] The structural characteristic parameters of the reinforced concrete column include length, width, height, longitudinal reinforcement diameter, longitudinal reinforcement quantity, stirrup diameter, stirrup spacing, cladding thickness, concrete uniaxial compressive strength and steel yield strength;

[0062] The bearing characteristic parameters of the reinforced concrete column refer to its axial static load;

[0063] In this embodiment, a typical scaled-down reinforced concrete column is taken as the research object, the reinforced concrete column has a length of 1900mm, a width of 200mm, a height of 200mm, a longitudinal reinforcement diameter of 8 longitudinal reinforcement quantities, a stirrup diameter of a stirrup spacing of 100mm, a cladding thickness of 25mm, a concrete specification of C40, a concrete compressive strength of 40MPa, a steel specification of HRB400, and a yield strength of 400MPa.

[0064] The axial static load of the reinforced concrete column is set to 320kN.

[0065] Step 2: Select the charge type, determine the charge material model parameters, give the charge striking accuracy and initiation mode;

[0066] In this embodiment, the charge type is set to TNT, the TNT explosive detonation and shock wave propagation process is described by the *MAT_HIGH_EXPLOSIVE_BURN material model and the *EOS_JWL state equation, and the explosive material model parameters are shown in the following table, in which the density, D CJ , P CJ are parameters related to the *MAT_HIGH_EXPLOSIVE_BURN material model, and the other parameters are related to the *EOS_JWL state equation.

[0067] Table 1 Charge material model parameters in the embodiment

[0068]

[0069] In this embodiment, the initiation mode is single-point initiation at the center of the upper end surface of the charge, and the striking accuracy is set to 0.2m.

[0070] Step 3: Set the design constraints for the cylindrical charge. The parameters that can be set as constraints include charge length L, charge diameter D, charge aspect ratio LDR, and charge mass M. There are two ways to set the constraints; in this embodiment, method 2 is used, and the charge aspect ratio constraint is LDR. min =0.5, LDR max =0.5, the charge mass constraint is M min =1kg, M max =1.4kg.

[0071] Step 4: Based on the constraints of cylindrical charge, generate cylindrical charge parameters that meet the constraints in batches. Depending on the constraint setting method in Step 3, there are two methods for batch generating cylindrical charge parameters. In this embodiment, method 2 is used. Based on the aspect ratio constraint 0.5≤LDR≤0.5 and the charge mass constraint 1≤M≤1.4, one aspect ratio sample LDR1 and three charge mass samples M1=1, M2=1.2, and M3=1.4 are generated respectively. The samples satisfy:

[0072]

[0073] Then, the parameters in the aspect ratio and mass samples of the charge are arbitrarily combined to form a 1×3 set of columnar charge parameters (LDR). i M j ), where 1≤i≤1, 1≤j≤3, and further, based on the cylindrical charge parameters (LDR) i M j Calculate the charge diameter D and charge length L:

[0074]

[0075] The table below lists all the parameters for the batch-generated cylindrical charges.

[0076] Table 2 lists the cylindrical charge parameters generated based on the constraints in the embodiments.

[0077] Charge parameter conditions Charge length-diameter ratio Charge mass / kg Charge length / mm Charge diameter / mm 1 0.5 1 58.03 116.08 2 0.5 1.2 61.68 123.34 3 0.5 1.4 64.92 129.85

[0078] Step 5: Conduct simulation for lightweight propellant design, including the following steps:

[0079] Step 5.1: Select any set of cylindrical charge parameters from Step 4;

[0080] Step 5.2: Establish a numerical simulation model of the pre-loaded axially compressed reinforced concrete column using LS-DYNA preprocessing; the model should include components such as the reinforced concrete column, axially compressed loading rod, and gasket. The simulation model is as follows: Figure 2As shown in Fig. 5, all nodes in region A are applied with full freedom constraints, and all nodes in region B are applied with constraints of all freedoms except axial displacement of the column, and axial pressure is applied to the end of the loading rod;

[0081] Step 5.3: According to the axial static load of the reinforced concrete column, a constant axial pressure of 320 kN is applied to the reinforced concrete column until the internal force of the structure is balanced. In this embodiment, the axial pressure is applied to 50 ms, Figure 3 (a) and (b) show the axial stress distribution at the initial time and the 50 ms time, respectively, Figure 4 The change process of the axial pressure of the structure is shown in Fig. 5, from Figure 3 、 Figure 4 It can be seen from Fig. 5 that the axial force of the structure is evenly distributed at 50 ms;

[0082] Step 5.4: Based on the simulation results of step 5.3, a full restart analysis is carried out, and air and explosive components are added, as shown in Fig. 5; Figure 5

[0083] Step 5.5: The explosive charge is detonated, and the damage state of the reinforced concrete column is continuously observed to determine whether the reinforced concrete column is crushed, and the simulation results are recorded, including “the column is crushed” or “the column is not crushed”;

[0084] Step 5.6: Determine whether all column charge parameters in step 4 have been traversed; if all have been completely traversed, end step 5; if not, return to step 5.1;

[0085] Step 6: The simulation results are counted, and the charge lightweight design results are selected. In the “column crushed” working condition, the charge with the smallest weight is selected as the lightweight design result.

[0086] Figure 6 The crushing state of the column when the charge mass is 1 kg, 1.2 kg and 1.4 kg is shown in Fig. 5. When the charge mass is 1.4 kg, the reinforced concrete column is crushed, so the column charge lightweight design result is that the charge mass is 1.4 kg, the charge diameter is 129.85 mm, and the charge length is 64.92 mm.​

Claims

1. A method for lightweight design of cylindrical charge for damaging reinforced concrete columns, characterized in that, The method comprises the following steps: Step 1: setting structural characteristic parameters and bearing characteristic parameters of the reinforced concrete column to be struck; Step 2: selecting a charge type, determining charge material model parameters, and giving a charge striking precision and an initiation mode; Step 3: setting column charge design constraint conditions, and the constraint condition parameters that can be set include a charge length L, a charge diameter D, a charge length-diameter ratio LDR and a charge mass M; Step 4: generating column charge parameters that meet the constraint condition requirements in batches according to the column charge constraint conditions, and the column charge parameter batch generation methods are different according to different constraint condition setting modes in Step 3; Step 5: carrying out charge lightweight design simulation, comprising the following steps: Step 5.1: selecting a group of column charge parameters in Step 4; Step 5.2: establishing a reinforced concrete column pre-axial compression numerical simulation model through LS-DYNA preprocessing; the components in the model should include a reinforced concrete column, an axial compression loading rod and a gasket; Step 5.3: applying a constant axial compression to the reinforced concrete column until the internal force of the structure is balanced according to the axial static load of the reinforced concrete column; Step 5.4: carrying out a complete restart analysis, and adding air and explosive components; Step 5.5: initiating the explosive charge, continuously observing the damage state of the reinforced concrete column, judging whether the reinforced concrete column is crushed or not, and recording the simulation results, which include "the column is crushed" or "the column is not crushed"; wherein the simulation result of "the column is crushed" refers to that the column is axially unstable under the simultaneous action of axial compression and explosive load; the simulation result of "the column is not crushed" refers to that the column remains axially stable under the simultaneous action of axial compression and explosive load; Step 5.6: judging whether all the column charge parameters in Step 4 have been traversed or not; if all the column charge parameters have been traversed, ending Step 5; if all the column charge parameters have not been traversed, returning to Step 5.1; Step 6: counting the simulation results, and selecting the charge lightweight design result, that is, the charge with the smallest weight in the working condition of "the column is crushed".

2. The cylindrical charge lightweight design method for damaging a reinforced concrete column according to claim 1, characterized by, In Step 1, the structural characteristic parameters of the reinforced concrete column include length, width, height, longitudinal reinforcement diameter, longitudinal reinforcement quantity, stirrup diameter, stirrup spacing, cladding thickness, concrete uniaxial compressive strength and steel yield strength; and the bearing characteristic parameter of the reinforced concrete column refers to the axial static load.

3. The cylindrical charge lightweight design method for damaging a reinforced concrete column according to claim 2, characterized by, In Step 3, the constraint condition setting modes include the following two modes: Mode 1: simultaneously setting the ranges of the charge length L and the charge diameter D as design constraint conditions; Charge length constraint: L min ≤ L ≤ L max where L min , L max are the minimum and maximum values of the charge length, respectively. Charge diameter constraint condition: D min ≤ D ≤ D max where D min , D max are minimum and maximum values of the charge diameter, respectively. Mode 2: simultaneously setting the ranges of the charge length-diameter ratio LDR and the charge mass M as design constraint conditions. Charge aspect ratio constraint: LDR min ≤ LDR ≤ LDR max where LDR min , LDR max are the minimum and maximum values of the charge aspect ratio, respectively. Charge mass constraint condition: M min ≤ M ≤ M max , where M min , M max are minimum and maximum values of the charge mass, respectively.

4. The cylindrical charge lightweight design method for damaging a reinforced concrete column according to claim 3, characterized by, In Step 4, for Approach 1, m charge length samples L1, L2, L3, …, Ln are generated from the charge length constraint condition L min ≤ L ≤ L max and n charge diameter samples D1, D2, D3, …, Dn are generated from the charge diameter constraint condition D min ≤ D ≤ D max respectively, which should satisfy: m L1 < L2 < L3 < … < Ln n and D1 < D2 < D3 < … < Dn. Then, any combination of parameters in the charge length sample and the charge diameter sample is formed into m x n groups of cylindrical charge size parameters (L i ,D j ), where 1≤i≤m, 1≤j≤n; For Mode 2, according to the charge aspect ratio constraint LDR min ≤ LDR ≤ LDR max and the charge mass constraint M min ≤ M ≤ M max respectively define m charge aspect ratio samples LDR1, LDR2, LDR3, …, LDR m and n charge mass samples M1, M2, M3, …, M n , which should satisfy: Then, any combination of parameters in the charge LDR samples and the charge mass samples is formed to form m x n groups of cylindrical charge parameters (LDR i ,M j ), where 1≤i≤m, 1≤j≤n, further, the charge diameter D and the charge length L can be calculated according to the cylindrical charge parameters (LDR i ,M j ).

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