A damage plasticity constitutive calculation method of concrete polymorphic material based on double driving architecture

Abstract

The application discloses a damage plastic constitutive calculation method of a concrete polymorphic material based on a double driving architecture. The calculation method comprises the following steps: obtaining material physical basic information and a characteristic length of a finite element grid; activating a double driving parameter cascade deduction engine based on a material matrix determination mechanism; introducing a crack band theory to perform displacement type damage conversion, converting cracking strain into crack opening displacement based on the characteristic length, and adaptively correcting an exponential softening coefficient; performing parallel calculation of tension and compression to obtain a tensile damage variable and a compressive damage variable; reconstructing a nonlinear unloading-reloading stiffness degradation trajectory, deducing a tensile-compressive asymmetric residual plastic strain, and dynamically giving a loading-unloading pinch coefficient; and data cleaning, cutting and numerical interface formatting output. The method breaks the limitation of traditional empirical formula, enables a single system to be downward compatible with low-strength extremely brittle materials, and expands the material application range of nonlinear finite element simulation.

Description

Technical Field

[0001] This invention relates to the field of data processing, and in particular to a method for calculating the damage-plastic constitutive model of concrete polymorphic materials based on a dual-drive architecture. Background Technology

[0002] In the field of civil engineering, with the development of numerical simulation technology, finite element analysis is widely used to evaluate the mechanical response of concrete and other material components or systems under complex stress states (such as seismic cyclic loads). Among them, the concrete damaged plasticity (CDP) model has become one of the most commonly used constitutive models for concrete in mainstream commercial finite element software (such as ABAQUS) because it can simultaneously consider the plastic yielding and stiffness degradation of materials.

[0003] To accurately apply the CDP model, a complete set of monotonic constitutive envelopes for the material and damage evolution parameters (including tensile and compressive damage variables) needs to be predefined. However, current techniques and data processing tools in the generation and preprocessing stages of CDP finite element parameters generally suffer from the following limitations:

[0004] First, existing technologies are largely based on empirical formulas for ordinary concrete, lacking adaptability to various special materials that are not ordinary concrete. Existing parameter derivation formulas typically impose a forced binding between material fracture energy, crushing energy, and other failure evolution parameters and macroscopic nominal strength (such as cubic compressive strength). With the development of engineering materials, special quasi-brittle materials such as autoclaved aerated concrete (AAC) or high-ductility concrete are widely used. Their fracture characteristics and macroscopic strength no longer conform to the empirical relationship of traditional ordinary concrete. Forcibly applying existing generation tools can lead to physical and logical conflicts in the underlying parameter matrix (e.g., calculating negative plastic strain), making existing technologies incompatible with the finite element modeling requirements of these special materials that are not ordinary concrete.

[0005] Second, existing parameter generation methods struggle to accurately track the unloading-reloading behavior of materials under cyclic loading, leading to inaccurate predictions of structural hysteretic energy dissipation. Existing methods for calculating damage variables (including recommended formulas from relevant standards and commonly used parameter calculation tools) generally assume that strain ratio factors are constant when describing material stiffness degradation. This assumption of constant coefficients ignores the nonlinear characteristics of damage development rates as crack propagation changes. In simulating cyclic loading conditions such as earthquakes, existing models often overestimate or underestimate the degree of stiffness degradation and fail to accurately characterize the pinching effect and asymmetric residual plastic deformation unique to quasi-brittle materials during tension-compression cyclic switching, ultimately affecting the reliability of overall structural energy dissipation analysis.

[0006] Third, existing strain softening models are prone to mesh sensitivity issues when simulating severe structural damage. Traditional parameter generation methods mostly output softened constitutive data based on cracking strain or inelastic strain. When nonlinear calculations enter the strain localization stage, this strain-based softening data causes the calculation results to heavily depend on the finite element mesh size (i.e., the denser the mesh, the smaller the energy dissipated during fracture). This can easily lead to singular solution matrices and computational non-convergence in simulations of tensile cracking or severe damage to large, complex components.

[0007] In summary, there is an urgent need for a computational method that can overcome mesh sensitivity, accurately reconstruct the degradation path of cyclic hysteresis stiffness, and possess adaptive processing capabilities for multi-state materials, in order to meet the data preprocessing requirements of finite element simulation in modern complex civil engineering. Summary of the Invention

[0008] This invention provides a method for calculating the damage-plastic constitutive properties of concrete polymorphic materials based on a dual-drive architecture, in order to solve the above-mentioned problems.

[0009] The damage-plastic constitutive calculation method for concrete multimorphic materials based on a dual-drive architecture includes the following steps:

[0010] S1. Obtain fundamental information about materials physics and the characteristic length of the finite element mesh;

[0011] S2. Activate the dual-drive parameter cascade deduction engine based on the material matrix determination mechanism: If the material is determined to be a special material that is not ordinary concrete, the preset empirical formula binding is removed and the customized non-standard fracture energy data is directly read; if the material is determined to be ordinary concrete and the calculation is enabled, the mechanical parameters are automatically calculated and cascaded based on a single macroscopic strength scalar.

[0012] S3. Introduce the crack zone theory to perform displacement-type damage transformation. Based on the characteristic length, the cracking strain is converted into crack opening displacement, and the exponential softening coefficient is adaptively corrected.

[0013] S4. Parallel calculation of tension and compression: The strain ratio coefficient is dynamically calculated using the underlying nonlinear polynomial equation, and then the tensile damage variable and the compressive damage variable are obtained through coupled calculation.

[0014] S5. Reconstruct the nonlinear unloading-reloading stiffness degradation trajectory, deduce the residual plastic strain of tension-compression asymmetry, and dynamically assign loading and unloading pinching coefficients.

[0015] S6, Data Cleaning, Truncation, and Numerical Interface Formatting Output.

[0016] Based on the aforementioned method for calculating the damage-plastic constitutive properties of concrete multimorphic materials using a dual-drive architecture, the calculation rules for activating the dual-drive parameter cascade derivation engine in step S2 based on the material matrix determination mechanism are as follows:

[0017] If the material is determined to be ordinary concrete, then further determine whether to use single-parameter estimation.

[0018] If single-parameter calculation is enabled, the single-parameter cascaded calculation engine is activated, calling the built-in GB / T 50010-2010 standard criteria to automatically calculate and cascade mechanical parameters based on a single macroscopic strength scalar; where the single macroscopic strength scalar is the cubic compressive strength f. cu Or the nominal grade; if it is determined that single-parameter calculation is not enabled, then the basic material physics information is read directly;

[0019] The calculation rules for activating the single-parameter cascaded inference engine are as follows:

[0020] S21. Calculate the standard value of axial compressive strength f of concrete. ck :

[0021] ;

[0022] S22. Calculate the average axial compressive strength f of concrete. cm :

[0023] ;

[0024] S23. Calculate the average axial tensile strength f of concrete. tm :

[0025] ;

[0026] S24. Automatically estimate the concrete fracture energy G based on the empirical formula for macroscopic strength. F With crushing energy G C :

[0027] ;

[0028] ;

[0029] If the material is determined to be a special material that is not ordinary concrete, the system will automatically deselect the empirical formula in the GB / T 50010-2010 standard. The underlying layer is forcibly bound, and the customized non-standard fracture energy G for this special material is forcibly read. F With crushing energy G C .

[0030] Based on the aforementioned method for calculating the damage-plastic constitutive properties of concrete multimorphic materials using a dual-drive architecture, step S3 specifically includes the following steps:

[0031] Determine whether to enable displacement-based damage transformation, and when it is determined in step S2 that the material is a special material that is not ordinary concrete, the system bottom layer forcibly enables the displacement-based damage transformation.

[0032] If so, the following steps are included:

[0033] S31. Introducing the crack zone theory and using the equivalent relationship to express the cracking strain ε ck Converted to crack opening displacement w:

[0034] ;

[0035] In the formula, h is the characteristic length;

[0036] S32. System adaptive inversion and correction of the tensile softening coefficient c:

[0037] ;

[0038] If it is determined that displacement-based damage transformation is not enabled, the system calls the traditional strain softening module, directly based on the macroscopic strength f. cu The pre-defined empirical formula is used to calculate the tensile softening coefficient c:

[0039] When f cu When ≤50.0MPa, When f cu When >50.0MPa, .

[0040] Based on the aforementioned method for calculating the damage-plastic constitutive properties of concrete multimorphic materials using a dual-drive architecture, the tensile damage variable in step S4... and pressure damage variables The calculation process is as follows:

[0041] Tensile damage variable d t The calculation process is as follows:

[0042] S41. Solve for the tensile monotonic constitutive damped response using the equation Extract the equivalent crack displacement w or crack strain ε ck And calculate the tensile undamaged elastic strain according to the following formula. :

[0043] ;

[0044] In the formula, σ t The nominal tensile stress is E0, and the initial elastic modulus is E0.

[0045] S42. Extract the maximum value of the independent variable in the process and solve for the normalized crack strain. Substituting into the underlying nonlinear polynomial equation, the tensile strain ratio coefficient k is dynamically calculated. t :

[0046] ;

[0047] S43. The dynamically obtained tensile strain ratio coefficient k t Substituting into the displacement-type damage evolution equation, calculate the tensile damage variable d. t :

[0048] ;

[0049] Compression damage variable d c The calculation process is as follows:

[0050] S41' Solve for the three-segment constitutive hardening-softening response under compression, and calculate the nominal compressive stress σ at each strain step. c And calculate the compressive inelastic strain ε according to the following formula. in :

[0051] ;

[0052] In the formula, ε c The total compressive strain is given; simultaneously, the compressive undamaged elastic strain is calculated according to the following formula. :

[0053] ;

[0054] S42' Extract the maximum value of the independent variable in the process and solve for the normalized inelastic strain. Substituting into the underlying nonlinear polynomial equation, the compressive strain ratio coefficient k is dynamically calculated. c :

[0055] ;

[0056] S43', The dynamically obtained compressive strain ratio coefficient k c Substituting into the strain-type damage evolution equation, calculate the compressive damage variable d. c :

[0057] .

[0058] Based on the aforementioned method for calculating the damage-plastic constitutive properties of concrete multimorphic materials using a dual-drive architecture, step S5 specifically includes the following steps:

[0059] Determine whether to reconstruct the cyclic load-reload path. If so, include the following steps:

[0060] S51. Rigorous derivation of asymmetric tensile residual plastic strain and compressive residual plastic strain :

[0061] ;

[0062] ;

[0063] S52. Introduce the local loading history variable ξ:

[0064] ;

[0065] In the formula, ε is the total strain of the current loading step, ε res To unload residual strain, ε peak This represents the historical peak strain.

[0066] S53. Dynamically assign nonlinear loading / unloading pinch coefficients based on the strain loading process:

[0067] Tension-reload pinch coefficient The coefficient of pinching under pressure and reloading ;

[0068] S54. Solve for the reconstructed nonlinear unloading-reloading stiffness degradation trajectory.

[0069] If not, skip the hysteresis reconstruction and retain and output the monotonic skeleton envelope data.

[0070] Based on the aforementioned method for calculating the damage-plastic constitutive properties of concrete multimorphic materials using a dual-drive architecture, in step S2, when the material is determined to be autoclaved aerated concrete, and the system activates the ALC custom mode, the tensile envelope cutoff stress ratio is forcibly adjusted to approach 0, and displacement-based damage transformation is forcibly enabled. Its tensile softening coefficient c strictly follows the inversion of the thermodynamic equivalent equation:

[0071] ;

[0072] At this point, the displacement decay equation becomes an extremely steep exponential form: .

[0073] Based on the aforementioned damage-plastic constitutive calculation method for concrete multimorphic materials with a dual-drive architecture, in step S2, when the material is determined to be high-ductility concrete, the system automatically identifies high fracture energy inputs and reconstructs its constitutive evolution path when activating the HDC customized mode:

[0074] The system divides the entire tensile curve into an "elastic rise segment", a "multi-crack pseudo-strain hardening segment", and a "localized softening segment of the main crack".

[0075] In the "localized softening segment of the main fracture", the system inverts the tensile softening coefficient c based on the large fracture energy:

[0076] .

[0077] Based on the aforementioned damage-plastic constitutive calculation method for concrete multimorphic materials using a dual-drive architecture, the material in S2 is determined to be cement mortar; when the system activates the mortar customization mode, it deactivates... The forced binding equation for ordinary concrete; the system directly reads the low-compression crushing energy G unique to mortar. C Input and reconstruct the equations for the pressure-softened segment;

[0078] The system's pressure softening parameters are based on the decoupling γ c Crushing energy G c Calculate independently:

[0079] ;

[0080] In the formula, b is the plastic strain proportionality coefficient.

[0081] Based on the aforementioned method for calculating the damage-plastic constitutive properties of concrete multimorphic materials using a dual-drive architecture, step S6 specifically includes the following steps:

[0082] S61. Numerically truncate and constrain the independent and damage variable matrices obtained from the solution, explicitly forcing the retention of the zero damage initiation point, at w=0 or ε. in At point =0, let d t =0,d c =0, and limit the damage cap to 0.999999;

[0083] S62. Execute the formatted interface output to generate the numerical text cards required for the Concrete Damaged Plasticity model in the finite element simulation software ABAQUS.

[0084] Compared with the prior art, the present invention has the following beneficial effects:

[0085] (1) The calculation method of the present invention breaks the limitations of traditional empirical formulas, enabling a single system to be backward compatible with low-strength brittle materials and upward compatible with high-ductility materials with strain hardening characteristics. It eliminates the physical logic conflicts that are easy to occur when generating special material parameters (such as negative plastic strain), and greatly expands the material application range of nonlinear finite element simulation.

[0086] (2) The calculation method of the present invention establishes a mapping between the strain softening behavior of the material and the finite element mesh size, and transforms the “strain space boundary” into the “displacement space boundary” from the underlying algorithm. This mechanism eliminates the mesh dependence caused by softening localization in nonlinear finite element analysis, and improves the calculation stability and solution convergence rate of large and complex components under extreme failure conditions.

[0087] (3) The calculation method of the present invention can more accurately characterize the nonlinear characteristics of the stiffness degradation of concrete materials in the early stage, the middle stage, and the later stage. The generated parameter matrix gives the finite element model the ability to accurately reconstruct the hysteretic energy dissipation characteristics of the structure, and improves the accuracy of mechanical response prediction of RC structure under cyclic loads such as earthquakes. Attached Figure Description

[0088] Figure 1 The flowchart shows the logic of the damage-plastic constitutive calculation method for concrete multimorphic materials based on a dual-drive architecture.

[0089] Figure 2 This is a monotonic physical damage feature map of an embodiment;

[0090] Figure 3 Simulation diagram of the stretching, pinching, and hysteresis path for an embodiment;

[0091] Figure 4 The simulation diagram of compression pinching and hysteresis path is shown in the example. Detailed Implementation

[0092] To make the technical problem to be solved, the technical solution and advantages of the present invention clearer, the following description will be provided in conjunction with the accompanying drawings. Figures 1 to 4 The technical solution of the present invention will be clearly and completely described in conjunction with specific embodiments.

[0093] In the technical solution of this invention, the term "multi-state material" refers to a general term for quasi-brittle and cement-based composite materials whose failure mechanisms, energy dissipation modes, and crack evolution characteristics exhibit distinctly different mechanical forms under complex stress. Specifically, the "multi-state" encompasses the following three typical physical evolution forms:

[0094] (1) Conventional softened state: represented by ordinary concrete, which exhibits standard exponential stress softening and moderate fracture energy dissipation characteristics after being subjected to tensile cracking.

[0095] (2) Extremely brittle sudden drop state: represented by high-porosity lightweight materials such as autoclaved aerated concrete (ALC), which have extremely low initial elastic modulus and extremely small fracture energy. After being tensile and cracked, the stress drops instantly, exhibiting an extremely brittle energy dissipation state.

[0096] (3) Strain hardening multi-crack state: represented by high ductility concrete (HDC), when subjected to tension, the cracks are distributed in multiple points, with extremely high fracture energy and macroscopically exhibiting significant "pseudo-strain hardening" and long-tailed ductility attenuation.

[0097] This invention aims to simultaneously and accurately simulate the three “polymorphic” mechanical behaviors with great physical contrasts through a single underlying adaptive algorithm architecture.

[0098] The damage-plastic constitutive calculation method for concrete multimorphic materials based on a dual-drive architecture includes the following steps:

[0099] S1. Obtain fundamental information about material physics and the characteristic length of the finite element mesh.

[0100] S2. Activate the dual-drive parameter cascade deduction engine based on the material matrix determination mechanism: If the material is determined to be a special material that is not ordinary concrete, the preset empirical formula binding is removed and the customized non-standard fracture energy data is directly read; if the material is determined to be ordinary concrete and the calculation is enabled, the mechanical parameters are automatically calculated and cascaded based on a single macroscopic strength scalar.

[0101] The calculation rules for activating the dual-drive parameter cascade inference engine based on the material matrix determination mechanism in step S2 are as follows:

[0102] If the material is determined to be ordinary concrete, then further determine whether to use single-parameter estimation.

[0103] If single-parameter calculation is enabled, the single-parameter cascaded calculation engine is activated, calling the built-in GB / T 50010-2010 standard criteria to automatically calculate and cascade mechanical parameters based on a single macroscopic strength scalar; where the single macroscopic strength scalar is the cubic compressive strength f. cu Alternatively, the nominal grade can be used; if it is determined that single-parameter calculation is not enabled, the basic material physics information can be read directly.

[0104] The calculation rules for activating the single-parameter cascaded inference engine are as follows:

[0105] S21. Calculate the standard value of axial compressive strength f of concrete. ck :

[0106] .

[0107] S22. Calculate the average axial compressive strength f of concrete. cm :

[0108] .

[0109] S23. Calculate the average axial tensile strength f of concrete. tm :

[0110] .

[0111] S24. Automatically estimate the concrete fracture energy G based on the empirical formula for macroscopic strength. F With crushing energy G C :

[0112] ;

[0113] .

[0114] In step S2, when the material is determined to be autoclaved aerated concrete, the system activates the ALC custom mode, forcibly adjusting the tensile envelope cutoff stress ratio to be close to 0, and forcibly enabling displacement-based damage transformation. Its tensile softening coefficient c strictly follows the thermodynamic equivalent equation inversion:

[0115]

[0116] At this point, the displacement decay equation becomes an extremely steep exponential form: .

[0117] In step S2, when the material is determined to be high-ductility concrete, the system automatically identifies high fracture energy inputs and reconstructs its constitutive evolution path upon activating the HDC customized mode.

[0118] The system divides the entire tensile curve into an "elastic rise segment", a "multi-crack pseudo-strain hardening segment", and a "localized softening segment of the main crack".

[0119] In the "localized softening segment of the main fracture", the system inverts the tensile softening coefficient c based on the large fracture energy:

[0120] .

[0121] S2 determines the material to be cement mortar; when the system activates the mortar customization mode, it deactivates... The forced binding equation for ordinary concrete; the system directly reads the low-compression crushing energy G unique to mortar. C Input and reconstruct the equations for the pressure-softened segment;

[0122] The system's pressure softening parameters are based on the decoupling γ c Crushing energy G c Calculate independently:

[0123] ;

[0124] In the formula, b is the plastic strain proportionality coefficient.

[0125] If the material is determined to be a special material that is not ordinary concrete, the system will automatically deselect the empirical formula in the GB / T 50010-2010 standard. The underlying layer is forcibly bound, and the customized non-standard fracture energy G for this special material is forcibly read. F With crushing energy G C .

[0126] S3. Introduce the crack zone theory to perform displacement-type damage transformation. Based on the characteristic length, the cracking strain is converted into crack opening displacement, and the exponential softening coefficient is adaptively corrected.

[0127] Step S3 specifically includes the following steps:

[0128] Determine whether to enable displacement-based damage transformation, and when it is determined in step S2 that the material is a special material that is not ordinary concrete, the system bottom layer forcibly enables the displacement-based damage transformation.

[0129] If so, the following steps are included:

[0130] S31. Introducing the crack zone theory and using the equivalent relationship to express the cracking strain ε ck Converted to crack opening displacement w:

[0131] ;

[0132] In the formula, h is the characteristic length;

[0133] S32. System adaptive inversion and correction of the tensile softening coefficient c:

[0134] ;

[0135] If it is determined that displacement-based damage transformation is not enabled, the system calls the traditional strain softening module, directly based on the macroscopic strength f. cu The pre-defined empirical formula is used to calculate the tensile softening coefficient c:

[0136] When f cu When ≤50.0MPa, When f cu When >50.0MPa, .

[0137] S4. Parallel calculation of tension and compression: The strain ratio coefficient is dynamically calculated using the underlying nonlinear polynomial equation, and then the tensile damage variable and the compressive damage variable are obtained through coupled calculation.

[0138] Tensile damage variables in step S4 and pressure damage variables The calculation process is as follows:

[0139] Tensile damage variable d t The calculation process is as follows:

[0140] S41. Solve for the tensile monotonic constitutive damped response using the equation Extract the equivalent crack displacement w or crack strain ε ck And calculate the tensile undamaged elastic strain according to the following formula. :

[0141] ;

[0142] In the formula, σ t The nominal tensile stress is E0, and the initial elastic modulus is E0.

[0143] S42. Extract the maximum value of the independent variable in the process and solve for the normalized crack strain. Substituting into the underlying nonlinear polynomial equation, the tensile strain ratio coefficient k is dynamically calculated. t :

[0144] ;

[0145] S43. The dynamically obtained tensile strain ratio coefficient k t Substituting into the displacement-type damage evolution equation, calculate the tensile damage variable d. t :

[0146] ;

[0147] Compression damage variable d c The calculation process is as follows:

[0148] S41' Solve for the three-segment constitutive hardening-softening response under compression, and calculate the nominal compressive stress σ at each strain step. c And calculate the compressive inelastic strain ε according to the following formula. in :

[0149] ;

[0150] In the formula, ε c The total compressive strain is given; simultaneously, the compressive undamaged elastic strain is calculated according to the following formula. :

[0151] ;

[0152] S42' Extract the maximum value of the independent variable in the process and solve for the normalized inelastic strain. Substituting into the underlying nonlinear polynomial equation, the compressive strain ratio coefficient k is dynamically calculated. c :

[0153] ;

[0154] S43', The dynamically obtained compressive strain ratio coefficient kc Substituting into the strain-type damage evolution equation, calculate the compressive damage variable d. c :

[0155] .

[0156] S5. Reconstruct the nonlinear unloading-reloading stiffness degradation trajectory, deduce the residual plastic strain of tension-compression asymmetry, and dynamically assign loading and unloading pinching coefficients.

[0157] Step S5 specifically includes the following steps:

[0158] Determine whether to reconstruct the cyclic load-reload path. If so, include the following steps:

[0159] S51. Rigorous derivation of asymmetric tensile residual plastic strain and compressive residual plastic strain :

[0160] ;

[0161] ;

[0162] S52. Introduce the local loading history variable ξ:

[0163] ;

[0164] In the formula, ε is the total strain of the current loading step, ε res To unload residual strain, ε peak This represents the historical peak strain.

[0165] S53. Dynamically assign nonlinear loading / unloading pinch coefficients based on the strain loading process:

[0166] Tension-reload pinch coefficient The pinching coefficient under pressure and reloading ;

[0167] S54. Solve for the reconstructed nonlinear unloading-reloading stiffness degradation trajectory;

[0168] If not, skip the hysteresis reconstruction and retain and output the monotonic skeleton envelope data.

[0169] S6, Data Cleaning, Truncation, and Numerical Interface Formatting Output.

[0170] Step S6 specifically includes the following steps:

[0171] S61. Numerically truncate and constrain the independent and damage variable matrices obtained from the solution, explicitly forcing the retention of the zero damage initiation point, at w=0 or ε. in At point =0, let d t=0,d c =0, and limit the damage cap to 0.999999;

[0172] S62. Execute the formatted interface output to generate the numerical text cards required for the Concrete Damaged Plasticity model in the finite element simulation software ABAQUS.

[0173] Compared with the prior art, the present invention has the following beneficial effects:

[0174] (1) This invention constructs an intelligent decision tree for the material matrix at the top level of the algorithm and innovatively proposes a "dual-drive" parameter cascade deduction architecture. For conventional engineering applications, the system has a built-in single-parameter cascade deduction engine, which can automatically reduce the dimensionality of the entire set of mechanical parameters by inputting only a single macroscopic strength index; while for special materials that are not ordinary concrete (such as high-ductility concrete HDC, autoclaved aerated concrete ALC, etc.), the system activates a high-order test customization mode, automatically removes the forced binding of the underlying standard formula, and directly reads the customized non-standard fracture energy data. This architecture breaks the limitations of traditional empirical formulas, enabling a single system to be backward compatible with low-strength extremely brittle materials and upward compatible with high-ductility materials with strain hardening characteristics, eliminating the physical logic conflicts that are easy to occur when generating parameters for special materials (such as negative values ​​for plastic strain), and greatly expanding the material applicability range of nonlinear finite element simulation.

[0175] (2) This invention introduces a displacement-type damage conversion mechanism based on crack zone theory into the underlying data processing flow. The algorithm forcibly reads the characteristic length h of the finite element mesh and uses the equivalent geometric mapping relationship to convert the cracking strain into crack opening displacement. At the same time, the system can adaptively back-calculate and correct the exponential softening coefficient. This method establishes a mapping between the strain softening behavior of the material and the finite element mesh size, and converts the "strain space boundary" into the "displacement space boundary" from the underlying algorithm. This mechanism eliminates the mesh dependence caused by softening localization in nonlinear finite element analysis and improves the computational stability and solution convergence rate of large and complex components under extreme failure conditions.

[0176] (3) In the core parallel computing module, this invention abandons the constant coefficient assumption and adopts a nonlinear polynomial equation based on normalized crack inelastic strain to dynamically solve the tensile and compressive strain ratio coefficients, and then coupled to calculate the damage variable d. t d cBased on this, the system activates a dynamic hysteresis path reconstruction algorithm to rigorously deduce the residual plastic strain with tension-compression asymmetry characteristics. A nonlinear dynamic pinching coefficient is assigned according to the strain loading history, thereby reconstructing a nonlinear unloading-reloading stiffness degradation trajectory. This method can more accurately characterize the nonlinear characteristics of concrete stiffness degradation—slow in the initial stage, accelerated in the middle stage, and gradual in the later stage. The generated parameter matrix endows the finite element model with the ability to accurately reconstruct the hysteresis energy dissipation characteristics of the structure, improving the prediction accuracy of the mechanical response of RC structures under cyclic loads such as earthquakes.

[0177] To better illustrate the computational mechanism by which this invention solves the problem of generating finite element parameters for special extremely brittle materials under the "adaptive generation architecture of multi-state materials," a typical autoclaved aerated concrete (ALC) model is used as an example to explain in detail how the underlying algorithm of this invention generates a complete set of finite element numerical parameters for the CDP model without physical and logical conflicts through "feature decoupling" and "displacement-type transformation."

[0178] Select "No" if the selected material matrix is ​​ordinary concrete, and activate "Advanced Test Customization Mode," selecting "Autoclaved Aerated Concrete (ALC)" as the material matrix; at this point, the system automatically removes the underlying empirical formula based on the strength of ordinary concrete (such as...). Forced binding of parameters (e.g., ALC) directly reads user-inputted ALC-customized physical base parameters:

[0179] The initial elastic modulus E0 = 2500.0 MPa;

[0180] Average compressive strength f cm =4.5MPa;

[0181] Average tensile strength f tm =0.45MPa;

[0182] Customized non-standard fracture energy G F =0.015 N / mm;

[0183] Custom crushing energy G C =1.2N / mm.

[0184] Meanwhile, the characteristic length h of the mesh element for subsequent nonlinear finite element analysis is set to 50 mm, and the tensile envelope cutoff stress ratio is set to a small value of 0.01 that approaches 0.

[0185] Because ALC materials are extremely brittle, if the output is based on the traditional "cracking strain ε"... ck In ABAQUS, softened data, once the mesh is distorted, can easily lead to local fractures and energy dissipation approaching zero, causing computational crashes (mesh sensitivity problem).

[0186] The system's underlying layer forcibly enables "displacement-based damage transformation," introducing crack zone theory. First, the elastic limit cracking strain of the ALC is calculated:

[0187]

[0188] The system rejects the use of macroscopic empirical formulas for ordinary concrete (such as...). Instead, it is based strictly on the minimum fracture energy G customized by ALC. F To ensure the conservation of thermodynamic energy Adaptive inversion and correction of the exponential softening coefficient c ALC :

[0189]

[0190] The system establishes the displacement attenuation equation for the tensile softening segment and calculates the nominal tensile stress σ. t :

[0191]

[0192] The equation exhibits a steep exponential decay consistent with the extremely brittle physical characteristics of ALC, and establishes a strict equivalent integral mapping relationship between strain softening behavior and finite element mesh size. This fundamentally eliminates the mesh dependency in tensile crack analysis of ALC components.

[0193] Parallel calculations of tension and compression were performed to obtain the tensile damage variable d. t and the pressure damage variable d c .

[0194] Among them, the tensile damage variable d t The calculation process is as follows:

[0195] Tensile damage variable d t The calculation process is as follows:

[0196] When the crack opening displacement w = 0.05 mm,

[0197] (1) Corresponding cracking strain ;

[0198] (2) Calculate the current nominal tensile stress. ;

[0199] (3) Calculate the non-destructive elastic strain in this step. .

[0200] The system abandons the assumption of constant coefficients and extracts normalized crack strain. Substituting into the underlying nonlinear polynomial equation, the tensile strain ratio coefficient k is dynamically solved. t (Assuming that k is calculated in this step)t =0.45). (k) t Substituting 0.45 into the displacement-type damage evolution equation, the corresponding ALC tensile damage variable d is calculated using coupled calculation. t :

[0201]

[0202] The d t The value accurately characterizes the extremely brittle nature of ALC materials, which suffer severe stiffness degradation (damage up to 93.1%) when a tiny crack opens (0.05 mm).

[0203] Compression damage variable d c The calculation process is as follows:

[0204] Because ALC has extremely low crushing energy (G C =1.2N / mm), at a certain calculation step in the nonlinear decreasing segment under compression (e.g., when the compressive strain reaches ε). c =0.005, exceeding the peak compressive strain ε cm (when =0.0028):

[0205] ① The system calculates the current nominal compressive stress based on the decoupled three-segment constitutive model. ;

[0206] ② Extract the compressive inelastic strain in this step

[0207] ;

[0208] ③ Calculate the non-destructive elastic strain in this step. .

[0209] Extracting normalized inelastic strain (Assuming the extreme value in this step is 0.5), substitute it into the underlying nonlinear polynomial equation to dynamically solve for the compressive strain ratio coefficient k. c (Assuming that k is calculated in this step) c =0.65). (k) c Substituting 0.65 into the strain-type damage evolution equation, the corresponding ALC compressive damage variable d is calculated using coupled calculation. c :

[0210]

[0211] This algorithm abandons the traditional assumption of constant coefficients and accurately reproduces the real physical process of the nonlinear evolution of ALC material with strain depth under pressure.

[0212] Deducing asymmetric residual plastic strain (to prevent physical-logical conflicts).

[0213] In traditional parameter generation tools, if the extremely low elastic modulus (2500.0MPa) and brittle parameters of ALC are forcibly input, negative values ​​are very likely to occur when calculating the residual strain after unloading, causing ABAQUS to report an error and exit.

[0214] This invention is strictly based on the inverse operation of the one-dimensional damage-plastic relationship, and derives the actual tensile residual plastic strain of the calculation step. With compressive residual plastic strain :

[0215]

[0216]

[0217] By introducing a truncation mechanism and rigorous inversion based on real damage variables, the system maintains the lower limit of physical logic (greater than 0), completely eliminating the physical logic paradox of "negative plastic strain" in special materials when parameters are generated.

[0218] Data cleaning and formatted output:

[0219] The system performs numerical cleaning on all generated ALC tensile and compressive evolution matrices. Explicitly, it forces the preservation of the zero-damage initiation point (i.e., at w=0 or ε). in At point =0, let d t =0,d c =0), and limit the damage upper limit to 0.999999 to prevent singularity in the solution matrix. After cleaning, the system automatically outputs results suitable for ABAQUS. These generated results can be directly used for nonlinear failure simulation of special brittle components such as ALC partition walls, exhibiting extremely high computational stability and convergence rate, as detailed below. Figures 2 to 4 As shown in Table 1, the data that can be copied to ABAQUS is as follows.

[0220] Table 1. Data table for CAE solver mapping

[0221]

[0222] Finally, it should be noted that the above-described embodiments are merely specific implementations of the present invention, used to illustrate the technical solutions of the present invention, and not to limit them. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the scope of the technology disclosed in the present invention, or make equivalent substitutions for some of the technical features; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered within the scope of protection of the present invention.

Claims

1. A method for calculating the damage-plastic constitutive model of concrete multimorphic materials based on a dual-drive architecture, characterized in that, Includes the following steps: S1. Obtain fundamental information about materials physics and the characteristic length of the finite element mesh; S2. Activate the dual-drive parameter cascade deduction engine based on the material matrix determination mechanism: If the material is determined to be a special material that is not ordinary concrete, the preset empirical formula binding is removed and the customized non-standard fracture energy data is directly read; if the material is determined to be ordinary concrete and the calculation is enabled, the mechanical parameters are automatically calculated and cascaded based on a single macroscopic strength scalar. S3. Introduce the crack zone theory to perform displacement-type damage transformation. Based on the characteristic length, the cracking strain is converted into crack opening displacement, and the exponential softening coefficient is adaptively corrected. S4. Parallel calculation of tension and compression: The strain ratio coefficient is dynamically calculated using the underlying nonlinear polynomial equation, and then the tensile damage variable and the compressive damage variable are obtained through coupled calculation. S5. Reconstruct the nonlinear unloading-reloading stiffness degradation trajectory, deduce the residual plastic strain of tension-compression asymmetry, and dynamically assign loading and unloading pinching coefficients. S6, Data Cleaning, Truncation, and Numerical Interface Formatting Output.

2. The damage-plastic constitutive calculation method for concrete multimorphic materials based on a dual-drive architecture according to claim 1, characterized in that, The calculation rules for activating the dual-drive parameter cascade inference engine based on the material matrix determination mechanism in step S2 are as follows: If the material is determined to be ordinary concrete, then further determine whether to use single-parameter estimation. If single-parameter calculation is enabled, the single-parameter cascaded calculation engine is activated, calling the built-in GB / T 50010-2010 standard criteria to automatically calculate and cascade mechanical parameters based on a single macroscopic strength scalar; where the single macroscopic strength scalar is the cubic compressive strength f. cu Or the nominal grade; if it is determined that single-parameter calculation is not enabled, then the basic material physics information is read directly; The calculation rules for activating the single-parameter cascaded inference engine are as follows: S21. Calculate the standard value of axial compressive strength f of concrete. ck : ； S22. Calculate the average axial compressive strength f of concrete. cm : ； S23. Calculate the average axial tensile strength f of concrete. tm : ； S24. Automatically estimate the concrete fracture energy G based on the empirical formula for macroscopic strength. F With crushing energy G C : ； ； If the material is determined to be a special material that is not ordinary concrete, the system will automatically deselect the empirical formula in the GB / T 50010-2010 standard. The underlying layer is forcibly bound, and the customized non-standard fracture energy G for this special material is forcibly read. F With crushing energy G C .

3. The method for calculating the damage-plastic constitutive model of concrete multimorphic materials based on a dual-drive architecture according to claim 2, characterized in that, Step S3 specifically includes the following steps: Determine whether to enable displacement-based damage transformation, and when it is determined in step S2 that the material is a special material that is not ordinary concrete, the system bottom layer forcibly enables the displacement-based damage transformation. If so, the following steps are included: S31. Introducing the crack zone theory and using the equivalent relationship to express the cracking strain ε ck Converted to crack opening displacement w: ； In the formula, h is the characteristic length; S32. System adaptive inversion and correction of the tensile softening coefficient c: ； If it is determined that displacement-based damage transformation is not enabled, the system calls the traditional strain softening module, directly based on the cubic compressive strength f. cu The pre-defined empirical formula is used to calculate the tensile softening coefficient c: When f cu When ≤50.0MPa, When f cu When >50.0MPa, .

4. The method for calculating the damage-plastic constitutive model of concrete multimorphic materials based on a dual-drive architecture according to claim 3, characterized in that, Tensile damage variables in step S4 and pressure damage variables The calculation process is as follows: Tensile damage variable d t The calculation process is as follows: S41. Solve for the tensile monotonic constitutive damped response using the equation Extract the equivalent crack displacement w or crack strain ε ck And calculate the tensile undamaged elastic strain according to the following formula. : ； In the formula, σ t The nominal tensile stress is E0, and the initial elastic modulus is E0. S42. Extract the maximum value of the independent variable in the process and solve for the normalized crack strain. Substituting into the underlying nonlinear polynomial equation, the tensile strain ratio coefficient k is dynamically calculated. t : ； S43. The dynamically obtained tensile strain ratio coefficient k t Substituting into the displacement-type damage evolution equation, calculate the tensile damage variable d. t : ； Compression damage variable d c The calculation process is as follows: S41' Solve for the three-segment constitutive hardening-softening response under compression, and calculate the nominal compressive stress σ at each strain step. c And calculate the compressive inelastic strain ε according to the following formula. in : ； In the formula, ε c The total compressive strain is given; simultaneously, the compressive undamaged elastic strain is calculated according to the following formula. : ； S42' Extract the maximum value of the independent variable in the process and solve for the normalized inelastic strain. Substituting into the underlying nonlinear polynomial equation, the compressive strain ratio coefficient k is dynamically calculated. c : ； S43', The dynamically obtained compressive strain ratio coefficient k c Substituting into the strain-type damage evolution equation, calculate the compressive damage variable d. c : 。 5. The method for calculating the damage-plastic constitutive model of concrete multimorphic materials based on a dual-drive architecture according to claim 4, characterized in that, Step S5 specifically includes the following steps: Determine whether to reconstruct the cyclic load-reload path. If so, include the following steps: S51. Rigorous derivation of asymmetric tensile residual plastic strain and compressive residual plastic strain : ； ； S52. Introduce the local loading history variable ξ: ； In the formula, ε is the total strain of the current loading step, ε res To unload residual strain, ε peak This represents the historical peak strain. S53. Dynamically assign nonlinear loading / unloading pinch coefficients based on the strain loading process: Tension-reload pinch coefficient The pinching coefficient under pressure and reloading ; S54. Solve for the reconstructed nonlinear unloading-reloading stiffness degradation trajectory; If not, skip the hysteresis reconstruction and retain and output the monotonic skeleton envelope data.

6. The method for calculating the damage-plastic constitutive model of concrete multimorphic materials based on a dual-drive architecture according to claim 2, characterized in that, In step S2, when the material is determined to be autoclaved aerated concrete, the system activates the ALC custom mode, forcibly adjusting the tensile envelope cutoff stress ratio to be close to 0, and forcibly enabling displacement-based damage transformation. Its tensile softening coefficient c strictly follows the thermodynamic equivalent equation inversion: ； At this point, the displacement decay equation becomes an extremely steep exponential form: ； In the formula, σ t Let w be the nominal tensile stress, and w be the crack opening displacement.

7. The method for calculating the damage-plastic constitutive model of concrete multimorphic materials based on a dual-drive architecture according to claim 2, characterized in that, In step S2, when the material is determined to be high-ductility concrete, the system automatically identifies high fracture energy inputs and reconstructs its constitutive evolution path upon activating the HDC customized mode. The system divides the entire tensile curve into an "elastic rise segment", a "multi-crack pseudo-strain hardening segment", and a "localized softening segment of the main crack". In the "localized softening section of the main fracture", the system inverts the tensile softening coefficient c based on the large fracture energy: 。 8. The method for calculating the damage-plastic constitutive model of concrete multimorphic materials based on a dual-drive architecture according to claim 2, characterized in that, S2 determines the material to be cement mortar; when the system activates the mortar customization mode, it deactivates... The forced binding equation for ordinary concrete; the system directly reads the low-compression crushing energy G unique to mortar. C Input and reconstruct the equations for the pressure-softened segment; The system's pressure softening parameters are based on the decoupling γ c Crushing energy G c Calculate independently: ； In the formula, b is the plastic strain proportionality coefficient, and ε cm denoted as peak compressive strain, h as characteristic length, and E0 as initial elastic modulus.

9. The method for calculating the damage-plastic constitutive model of concrete multimorphic materials based on a dual-drive architecture according to claim 5, characterized in that, Step S6 specifically includes the following steps: S61. Numerically truncate and constrain the independent and damage variable matrices obtained from the solution, explicitly forcing the retention of the zero damage initiation point, at w=0 or ε. in At point =0, let d t =0,d c =0, and limit the damage cap to 0.999999; S62. Execute the formatted interface output to generate the numerical text cards required for the Concrete Damaged Plasticity model in the finite element simulation software ABAQUS.

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