Concrete elastic-plastic damage model valuing method considering constraint effect

Abstract

The invention discloses a concrete elastic-plastic damage model valuing method considering a constraint effect. The concrete elastic-plastic damage model valuing method comprises the following steps: acquiring stress-strain curves of concrete in different constraint states; secondly, calculating the constraint stress of the concrete based on the yield surface in an equivalent pseudo-triaxial stress state; converting a stress-strain curve of the concrete based on the yield surface in a constraint state into a stress-strain curve in a uniaxial stress state; then plastic flow correction is carried out on the concrete based on the plastic potential function in a constraint state; and finally performing material unit test verification and component numerical simulation calculation. On the basis of the constitutive model yield surface, a constraint stress calculation method and a curve conversion process are deduced, and stress-strain curve integration is achieved; and meanwhile, a plastic expansion angle correction formula is deduced, so that numerical simulation better fits a test result, the strength and ductility improvement of the concrete under a constraint effect can be accurately simulated, and the accuracy of numerical simulation of a complex structure is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of constitutive relations of building materials, and in particular to a method for determining the value of a concrete elastic-plastic damage model taking constraint effects into consideration. Background Art

[0002] With the continuous deepening of concrete research, the phenomenon of significant improvement in the strength and ductility of concrete under confinement has attracted more and more attention. Based on this, a variety of confined concrete structures have been derived, such as steel tube confined concrete, fiber reinforced plastic (FRP) confined concrete, and FRP confined steel concrete.

[0003] Steel tube confined concrete (also known as steel tube concrete), as an important representative of confined concrete structures, has been widely used in actual projects such as China Zun, Guangzhou West Tower, and Beijing Metro Line 1, and corresponding standards have been formed in different regions such as China, Japan, Europe and the United States.

[0004] Although confined concrete structures have been widely used in actual engineering, the numerical simulation research on the mechanical properties of the concrete under the confinement effect is still relatively lagging. In the numerical simulation research of concrete using the finite element method, the concrete damage plasticity constitutive method (CDP) of the well-known software ABAQUS is widely used. However, its numerical calculation results are often quite different from the experimental test data, especially in simulating the ductility improvement phenomenon of concrete under confinement. This shows that the accuracy of the numerical simulation of complex confined concrete structures based on this method still needs to be improved. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for determining the value of a concrete elastic-plastic damage model taking into account the constraint effect in order to solve the problems existing in the prior art.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] A method for determining the value of a concrete elastoplastic damage model considering constraint effects includes the following steps:

[0008] Step 1: Based on existing research results, concrete pseudo-triaxial and concrete true triaxial tests, an empirical model is established to obtain the stress-strain curves of concrete under different constraint states;

[0009] The stress-strain curve includes a stress-inelastic strain curve ( ) and the derivative curve of lateral plastic strain to axial plastic strain ( ),in and are the stress and inelastic strain of concrete under restraint state; are the plastic strains in the three directions corresponding to the principal stresses.

[0010] Step 2: Equivalent the stress state of concrete under complex loading to the stress state of concrete under pseudo-triaxial loading mode. The equivalent equation is as follows:

[0011]

[0012] in ( ) is the concrete yield surface function with stress state as input, are the principal stresses of concrete under complex stress conditions, and are the restraint stresses of the concrete stress state under pseudo-triaxial loading mode, , substitute the yield surface function into the equivalent equation and calculate .

[0013] Preferably, the yield surface function adopts the Barcelona yield surface function of the CDP model in ABAQUS software, and its expression is as follows:

[0014]

[0015] in is the maximum value among the principal stresses, <·> takes a positive sign, , is the input stress and inelastic strain curve, , , is the parameter of concrete under multiaxial stress state;

[0016] In the pseudo-triaxial test of concrete, the load state (i.e. ), Mises equivalent stress and hydrostatic pressure for:

[0017]

[0018]

[0019] Substituting the Barcelona yield surface function into the equivalent equation, the following formula can be obtained:

[0020]

[0021] Thus we can solve:

[0022]

[0023] Substituting the yield surface function into the equivalent equation, the following formula is obtained:

[0024]

[0025] Preferably, and The values of are 0.12 and 3.0 respectively.

[0026] The above steps theoretically derive the calculation method of equivalent constraint stress, which builds a bridge between the solid finite element numerical simulation of concrete and the stress-strain curve under different constraint stress states.

[0027] Step 3: To be equivalent, the stress state of concrete under pseudo-triaxial loading mode is equivalent to the stress state of concrete under uniaxial loading. The equivalent formula is as follows:

[0028]

[0029] in is the stress of concrete under uniaxial loading, and the yield surface function is substituted into the equivalent formula to obtain ;

[0030] Preferably, the yield surface function adopts the Barcelona yield surface function of the CDP model in ABAQUS software, and its expression is as follows:

[0031]

[0032] According to the Barcelona yield surface function, concrete under uniaxial load is:

[0033]

[0034]

[0035]

[0036]

[0037] According to the Barcelona yield surface function, concrete under pseudo-triaxial loading state:

[0038]

[0039]

[0040]

[0041]

[0042] According to the equivalent formula, the stress state of concrete under pseudo-triaxial loading mode is equivalent to the stress state of concrete under uniaxial loading, and the following formula is obtained:

[0043]

[0044] Thus the following formula is derived:

[0045] .

[0046] The above steps theoretically derive the transformation process of the stress-strain curve of concrete from the constrained state to the uniaxial stress state, and realize the integration of the stress-strain curves of concrete under different constrained stress states.

[0047] Step 4: Use flow potential function , through the flow law , in real time during the calculation, the parameter values in the plastic potential function are corrected , is the stress tensor of concrete;

[0048] Preferably, according to the flow law in elastic-plastic mechanics theory, ,in is the size of the plastic strain increment, given by Determine the direction of plastic strain increment.

[0049] So that the plastic flow satisfies the plastic principal strain-lateral strain curve ( ).

[0050] Preferably, the expression of the plastic potential function used in the CDP model in ABAQUS software is as follows:

[0051]

[0052] Plugging this into the above flow law and using the chain rule for function differentiation, the process is as follows:

[0053]

[0054]

[0055] make

[0056]

[0057]

[0058] Will and Substituting the flow laws respectively, we get the following expressions:

[0059]

[0060]

[0061] Will and Dividing them, we get the following expression:

[0062]

[0063] When the material develops plasticity, Much smaller than , so it is ignored.

[0064]

[0065] Pick Substitute into the above formula

[0066]

[0067] Especially, when When , the plastic strain of the material develops under pseudo triaxial loading.

[0068]

[0069] Step 5: Based on the existing test data, the following formula for the derivative of lateral plastic strain to axial plastic strain is proposed, and based on this formula, real-time back calculation is performed. , making the strain development of numerical simulation more consistent with the experimental results.

[0070]

[0071]

[0072] in are the peak point strain and stress of the material axial stress-strain curve under the current constraint stress, is the axial plastic strain, is the lateral plastic strain.

[0073] Step 6: Complete the material property assignment through the above steps, establish the material unit test model and the complex constrained concrete structure model, and extract the calculation results.

[0074] The material unit test model and the complex constrained concrete structure model are established using ABAQUS software, and calculations are performed using ABAQUS.

[0075] The calculation results are compared with the empirical model and test data to verify the accuracy of the calculation results, and the calculation results are used to predict the mechanical properties of complex confined concrete structures.

[0076] Compared with the prior art, the present invention has the following beneficial effects:

[0077] 1. The method provided by this invention is based on the yield surface of the constitutive model used by the material, and theoretically derives the calculation method of the equivalent constraint stress, which builds a bridge between the solid finite element numerical simulation of concrete and the stress-strain curves under different constraint stress states.

[0078] 2. The method provided by the present invention is based on the yield surface of the constitutive model used by the material, and theoretically derives the transformation process of the stress-strain curve of concrete from the constrained state to the uniaxial stress state, realizing the integration of the stress-strain curves of concrete under different constrained stress states.

[0079] 3. The method provided by the present invention derives a revised calculation formula for the plastic expansion angle based on the plastic potential function of the constitutive model used for the material, so that the strain development of the numerical simulation is more consistent with the experimental results.

[0080] 4. The method provided by the present invention is applicable to all yield surfaces in the CDP model, so that the significant improvement in the strength and ductility of concrete under the confinement effect can be accurately simulated in ABAQUS, which improves the accuracy of the numerical simulation of complex confined concrete structures and makes the numerical simulation results have reference value in practical applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0081] Figure 1 Schematic diagram of concrete in an active restraint state according to an embodiment of the present invention;

[0082] Figure 2 Schematic diagram of concrete in a passive restraint state according to an embodiment of the present invention;

[0083] Figure 3 Graph showing an empirical model of stress-strain curves of concrete under different restraint stresses in an embodiment of the present invention;

[0084] Figure 4 : This is a graph showing equivalent uniaxial stress-inelastic strain curves of concrete under different restraint stresses in an embodiment of the present invention;

[0085] Figure 5 This is a diagram of a finite element unit test model in an embodiment of the present invention;

[0086] Figure 6 10MP confinement stress in the concrete numerical calculation model and the empirical model of the embodiment of the present invention;

[0087] Figure 7 30MP confinement stress in the concrete numerical calculation model and the empirical model of the embodiment of the present invention;

[0088] Figure 8 1 is a comparison diagram of the numerical calculation model and the empirical model of concrete under 50MP confinement stress in an embodiment of the present invention;

[0089] Figure 9 A finite element model of concrete plastic strain flow, a proposed calculation formula, and a comparison chart of specific test data in an embodiment of the present invention;

[0090] Figure 10 Schematic diagram of the finite element method model in an embodiment of the present invention;

[0091] Figure 11 is a function diagram of normal hard contact in finite element analysis in an embodiment of the present invention;

[0092] Figure 12 is a function diagram of the tangential penalty function in the finite element analysis in an embodiment of the present invention;

[0093] Figure 13 A comparison diagram of the force-displacement curves obtained by numerical calculation and testing in an embodiment of the present invention;

[0094] Figure 14 The internal concrete damage distribution diagram calculated by the finite element method in an embodiment of the present invention;

[0095] Figure 15 A schematic diagram of an embodiment of the present invention;

[0096] In the figure: 1. Stress-strain curve 1; 2. Stress-strain curve 2; 3. Stress-strain curve 3; 4. Stress-inelastic strain curve 1; 5. Stress-inelastic strain curve 2; 6. Stress-inelastic strain curve 3; 7. Empirical formula curve; 8. Finite element method (USDFLD correction) curve; 9. Finite element method (no correction) curve; 10. Experimental data. DETAILED DESCRIPTION

[0097] The following will clearly and completely describe the technical solution of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0098] In the description of the present invention, it should be noted that the terms "middle", "upper", "lower", "left", "right", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the present invention.

[0099] like Figures 1 to 13 As shown, the specific scheme of the embodiment is as follows: A method for determining the value of a concrete elastoplastic damage model considering the constraint effect is applied to ultra-high performance concrete containing coarse aggregate mixed with fibers, comprising the following steps:

[0100] Step 1: Based on existing research results, pseudo-triaxial and true triaxial tests of concrete, select and establish an empirical model to describe the stress-inelastic strain curve of concrete under different constraint states ( ) and the plastic principal strain-lateral strain curve ( ).in and are the stress and inelastic strain of concrete under restraint state; are the plastic strains in the three directions corresponding to the principal stresses.

[0101] Figure 1 and Figure 2 The schematic diagram of active constraint of concrete and the schematic diagram of passive constraint of concrete are shown respectively.

[0102] The stress-strain curve in the above steps adopts the formula based on GB50010, and the specific formula is as follows:

[0103]

[0104]

[0105]

[0106]

[0107]

[0108]

[0109]

[0110]

[0111]

[0112]

[0113] In this embodiment, They are set to 120Mpa, 0 and 0.02 respectively.

[0114] like Figure 3 As shown, the empirical model in the above steps includes a stress-strain curve 1 with a constraint stress of 10 MPa, a stress-strain curve 2 with a constraint stress of 30 MPa, and a stress-strain curve 3 with a constraint stress of 50 MPa.

[0115] Step 2: To uniformly apply the stress-inelastic strain curve in step 1, it is necessary to equate the stress state of concrete under complex loading to its stress state under the pseudo-triaxial loading mode. The key point is to calculate the constraint stress of concrete under the equivalent pseudo-triaxial stress state. This embodiment is based on the principles of elastic-plastic mechanics and uses the calculation result of the concrete stress tensor in the yield surface function as an equivalent quantity to derive the calculation formula for the constraint stress of concrete under the equivalent pseudo-triaxial stress state.

[0116] The stress state of concrete under complex loading is equivalent to the stress state of concrete under pseudo-triaxial loading mode. The equivalent equation is as follows:

[0117]

[0118] in ( ) is the concrete yield surface function with stress state as input, are the principal stresses of concrete under complex stress conditions, and are the restraint stresses of the concrete stress state under pseudo-triaxial loading mode, , substitute the yield surface function into the equivalent equation and calculate .

[0119] The yield surface function adopts the Barcelona yield surface function of the CDP model in ABAQUS software, and its expression is as follows:

[0120]

[0121] in is the maximum value among the principal stresses, <·> takes a positive sign, , is the input stress and inelastic strain curve, , , is the parameter of concrete under multiaxial stress state;

[0122] In the pseudo-triaxial test of concrete, the load state (i.e. ), Mises equivalent stress and hydrostatic pressure for:

[0123]

[0124]

[0125] Substituting the Barcelona yield surface function into the equivalent equation, we can obtain the following formula:

[0126]

[0127] Thus we can solve:

[0128]

[0129] Substituting the yield surface function into the equivalent equation, we obtain the following formula:

[0130]

[0131] and The values of are 0.12 and 3.0 respectively.

[0132] According to the formula derived in step 2, the USDFLD subroutine is written in Fortran, then compiled and called in ABAQUS software. In the USDFLD subroutine of ABAQUS software, the three principal stresses of the current element, SP1, SP2, and SP3, can be obtained and introduced into the calculation formula proposed above:

[0133]

[0134]

[0135] That is, the constraint stress under the corresponding equivalent pseudo-triaxial state can be calculated .

[0136] Step 3: Calculate the result in the yield surface function using the current concrete stress tensor As an equivalent quantity, the stress state of concrete under pseudo-triaxial loading mode is equivalent to the stress state of concrete under uniaxial loading, and the stress-strain curve of concrete under constraint state is completed ( ) to the uniaxial stress-strain curve under uniaxial loading. The equivalent formula based on the yield surface is as follows:

[0137]

[0138] in is the stress of concrete under uniaxial loading, and the yield surface function is substituted into the equivalent formula to obtain ;

[0139] The yield surface function adopts the Barcelona yield surface function of the CDP model in ABAQUS software, and its expression is as follows:

[0140]

[0141] According to the Barcelona yield surface function, concrete under uniaxial load is:

[0142]

[0143]

[0144]

[0145]

[0146] According to the Barcelona yield surface function, concrete under pseudo-triaxial loading state:

[0147]

[0148]

[0149]

[0150]

[0151] According to the equivalent formula, the stress state of concrete under pseudo-triaxial loading mode is equivalent to the stress state of concrete under uniaxial loading, and the following formula is obtained:

[0152]

[0153] Thus the following formula is derived:

[0154] .

[0155] In the material modeling of ABAQUS software, its hardening rule requires the input of the stress-inelastic strain curve of the equivalent uniaxial stress state. Using the formulas of steps 2 and 3, the stress-strain curve under the constraint state in step 1 is converted to obtain the equivalent uniaxial stress-strain curve under different constraint stresses. By further eliminating its elastic part, the stress-inelastic strain curve under the equivalent uniaxial stress state can be obtained.

[0156] like Figure 4As shown, the empirical model in the above steps includes a stress-inelastic strain curve 1 for the equivalent uniaxial stress state with a constraint stress of 10 MPa, a stress-inelastic strain curve 2 for the equivalent uniaxial stress state with a constraint stress of 30 MPa, and a stress-inelastic strain curve 3 for the equivalent uniaxial stress state with a constraint stress of 50 MPa.

[0157] Step 4: According to the plastic force function and flow law in the elastic-plastic mechanics theory, use the flow potential function , the parameter values in the plastic potential function are modified in real time during the calculation, where are the plastic strains in the three directions corresponding to the principal stresses, is the plastic expansion angle that needs to be corrected, is the stress tensor of concrete;

[0158] According to the flow law in elastic-plastic mechanics theory, ,in is the size of the plastic strain increment, given by Determine the direction of plastic strain increment.

[0159] Thus, the plastic flow of concrete under constraint state is corrected so that the plastic flow of concrete satisfies the plastic principal strain-lateral strain curve ( ).

[0160] The expression of the plastic potential function used in the CDP model in ABAQUS software is as follows:

[0161]

[0162] Plugging this into the above flow law and using the chain rule for function differentiation, the process is as follows:

[0163]

[0164]

[0165] make

[0166]

[0167]

[0168] Will and Substituting the flow laws respectively, we get the following expressions:

[0169]

[0170]

[0171] Will and Dividing them, we get the following expression:

[0172]

[0173] When the material develops plasticity, Much smaller than , so it is ignored.

[0174]

[0175] Pick Substitute into the above formula

[0176]

[0177] Especially, when When , the plastic strain of the material develops under pseudo triaxial loading.

[0178]

[0179] Step 5: Real-time back calculation based on the following formula for the derivative of lateral plastic strain to axial plastic strain , making the strain development of numerical simulation more consistent with the experimental results.

[0180]

[0181]

[0182] in are the peak point strain and stress of the material axial stress-strain curve under the current constraint stress, is the axial plastic strain, is the lateral plastic strain.

[0183] According to the formula derived in step 5, the USDFLD subroutine is written in Fortran language, and then compiled and called in ABAQUS software to realize the plastic flow correction under multi-axial loading.

[0184] Step 6: Use ABAQUS software to assign material properties according to the requirements of the above steps, establish a material unit test model and a complex constrained concrete structure model and submit them for calculation, and test the proposed method for determining the value of the concrete elastic-plastic damage model considering the constraint effect.

[0185] The material unit test model is as follows Figure 5 As shown in the figure, the stress-strain curves under different constraint stresses can be calculated based on the ABAQUS material unit test model.

[0186] After the modeling is completed, the calculation results are extracted and compared with the aforementioned empirical model and test data to verify the effectiveness and accuracy of the proposed method and predict the mechanical properties of complex confined concrete structures.

[0187] like Figure 6 、 Figure 7 and Figure 8 As shown in the figure, the comparison between the empirical model of the stress-strain curve and the numerical calculation results is respectively shown. According to the comparison results, it can be concluded that the ABAQUS-based concrete elastic-plastic damage model considering the constraint effect proposed in this embodiment can more accurately simulate the mechanical behavior of concrete under the constraint state compared with other existing technical solutions.

[0188] like Figure 9 As shown, a comparison diagram of the finite element model of concrete plastic strain flow, the proposed calculation formula, and specific experimental data is shown, including the empirical formula curve 7, the finite element method (USDFLD correction) curve 8, the finite element method (uncorrected) curve 9, and the experimental data 10. According to the comparison, it can be seen that the finite element method (USDFLD correction) curve 8 obtained after correction by the method proposed in this embodiment can more accurately describe the plastic strain development of concrete under different confining pressures than the finite element method (uncorrected) curve 9. By correcting the plastic expansion angle, it is also achieved that the finite element model can accurately predict the plastic strain development of concrete under different confining pressures.

[0189] This embodiment also uses this constitutive model to perform numerical simulations on the most representative steel tube concrete column under monotonic compressive load. Figure 10 、 Figure 11 and Figure 12 As shown in Figure 2, the three together show the schematic diagram of the finite element model of the steel tube concrete column.

[0190] The pairs of interacting objects in the finite element model schematic are ultra-high performance concrete and end plates, and steel pipes and end plates. In the real world, these pairs are connected by welding and general contact, respectively. In finite element modeling, appropriate modeling methods, such as bonding and general contact, need to be selected based on actual conditions to simulate the interactions between these pairs of interacting objects.

[0191] Figure 13 The force-displacement curve of the numerical calculation is compared with the force-displacement curve of the experiment. It can be seen that the two are very close. Using the constitutive model of confined concrete proposed in the present invention, the force-displacement curve of steel tube concrete can be accurately predicted.

[0192] Figure 14 Numerically calculated internal concrete damage maps are shown.

[0193] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for determining the value of a concrete elastoplastic damage model considering constraint effects, characterized in that: The following steps are involved: Obtain stress-strain curves of concrete under different constraint states; The stress state of concrete under complex loading is converted to the stress state of concrete under pseudo-triaxial loading mode through yield surface equivalence and stress space deviatoric plane equivalence. The equivalent equation is as follows: in ( ) is the concrete yield surface function with stress state as input, are the principal stresses of concrete under complex stress conditions, and are the axial stress and constraint stress of concrete under pseudo-triaxial loading mode, and the yield surface function is substituted into the equivalent equation to obtain ; by As an equivalent quantity, the stress state of concrete under pseudo-triaxial loading mode is equivalent to the stress state of concrete under uniaxial loading. The equivalent formula is as follows: in is the stress of concrete under uniaxial loading, and the yield surface function is substituted into the equivalent formula to obtain ; Using flow potential function , through the flow law , in real time during the calculation, the parameter values in the plastic potential function are corrected , in are the plastic strains in the three directions corresponding to the principal stresses, is the plastic expansion angle that needs to be corrected, is the stress tensor of concrete; Through the above steps, the material property assignment is completed, the material unit test model and the complex constrained concrete structure model are established, and the calculation results are extracted.

2. The method for determining the value of the concrete elastoplastic damage model considering the constraint effect according to claim 1, characterized in that: The stress-strain curve includes a stress-inelastic strain curve ( ) and the derivative curve of lateral plastic strain to axial plastic strain ( ),in and are the stress and inelastic strain of concrete under restraint state; are the plastic strain increments in the three main directions respectively.

3. The method for determining the value of the concrete elastoplastic damage model considering the constraint effect according to claim 1, characterized in that: Based on existing research results, concrete pseudo-triaxial and concrete true triaxial tests, an empirical model is established to obtain the stress-strain curves of concrete under different constraint states.

4. The method for determining the value of the concrete elastoplastic damage model considering the constraint effect according to claim 1, characterized in that: The yield surface function adopts the Barcelona yield surface function of the CDP model in ABAQUS software. Substituting the yield surface function into the equivalent equation, the following formula is obtained: in and is the Mises equivalent stress and hydrostatic pressure, , , are the three principal stresses of the stress tensor, , are the parameters of concrete under multiaxial stress state.

5. The method for determining the value of the concrete elastoplastic damage model considering the constraint effect according to claim 1, characterized in that: The yield surface function adopts the Barcelona yield surface function of the CDP model in ABAQUS software. Substituting the yield surface function into the equivalent formula, the following formula is obtained: 。 6. The method for determining the value of the concrete elastoplastic damage model considering the constraint effect according to claim 2, characterized in that: According to the flow law in elastic-plastic mechanics theory, , so that the plastic flow satisfies the derivative curve of lateral plastic strain to axial plastic strain ( ).

7. The method for determining the value of the concrete elastoplastic damage model considering the constraint effect according to claim 1, characterized in that: Based on the plastic potential function used in the CDP model in ABAQUS software, combined with the flow potential function , we can get the following formula: in Furthermore, when When , the plastic strain of the material develops under pseudo-triaxial loading. 。 8. The method for determining the value of the concrete elastoplastic damage model considering the constraint effect according to claim 1, characterized in that: The formula for the derivative of lateral plastic strain with respect to axial plastic strain is as follows: in , are the peak strain and stress of the axial stress-strain curve of the material under the current constraint stress. is the axial plastic strain is the lateral plastic strain.

9. The method for determining the value of the concrete elastoplastic damage model considering the constraint effect according to claim 1, characterized in that: The material unit test model and the complex constrained concrete structure model are established using ABAQUS software, and calculations are performed using ABAQUS.

10. The method for determining the value of the concrete elastoplastic damage model considering the constraint effect according to claim 1, characterized in that: The calculation results are compared with the empirical model and test data to verify the accuracy of the calculation results, and the calculation results are used to predict the mechanical properties of complex confined concrete structures.

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