A constitutive calculation method, device and equipment for improving GTN model and medium
By introducing a preset switching mechanism between the improved GTN yield criterion and the Von Mises yield criterion into the GTN model, the iterative divergence problem caused by negative porosity was solved, and stable numerical simulation of porous metallic materials was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHENZHEN WANZE ZHONGNAN RES INST CO LTD
- Filing Date
- 2026-04-07
- Publication Date
- 2026-07-10
AI Technical Summary
The traditional GTN model suffers from divergence and non-convergence in numerical iteration due to negative porosity during the numerical iteration process, which affects the stability of numerical simulation of porous metal materials.
In the implicit finite element method, the initial porosity of the target material is obtained and it is determined whether it is greater than the preset minimum porosity threshold. If it is greater than the threshold, the improved GTN yield criterion is used for constitutive calculation. Otherwise, the Von Mises yield criterion is used to ensure that the shape of the yield function changes continuously and to avoid iterative divergence caused by negative porosity.
The numerical stability and implicit iterative convergence of the GTN model in the low porosity stage were achieved, ensuring the stability and reliability of material constitutive calculations, and making it suitable for numerical simulation of porous metallic materials.
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Figure CN122369715A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of thermal radiation simulation, and in particular to a constitutive calculation method, apparatus, device and medium for improving GTN models. Background Technology
[0002] Porous metallic materials and metal castings containing shrinkage cavities and porosity defects are widely used in aerospace, machinery manufacturing, and other fields. Hot isostatic pressing (HIP) and hot compression forming are core technologies for improving the density of these materials and eliminating internal defects. To achieve precise optimization of process parameters and reduce trial production costs, numerical simulation of the compression forming process of these materials has become a necessary technical approach.
[0003] Currently, implicit finite element method is mostly used in existing technologies to numerically simulate the compression forming process of this type of material. Specifically, the Gurson-Tvergaard-Needleman (GTN) model is constructed to characterize the yielding and deformation behavior of porous metallic materials, thereby achieving accurate numerical simulation of the compression forming process of this type of material.
[0004] However, the GTN model suffers from significant numerical stability defects in implicit finite element calculations under compressive loads: when the material porosity approaches 0, the hyperbolic cosine function term in the model's yield function tends towards infinity. Furthermore, during numerical iteration, the hyperbolic cosine function value becomes discontinuous when negative porosity occurs, leading to abrupt changes in the yield function shape. This ultimately causes residual oscillations and computational divergence in the Newton-Raphson iteration process, making the native GTN model in mainstream finite element software such as ANSYS and ABAQUS difficult to apply to the numerical simulation of compression processes such as hot isostatic pressing of alloy castings. Therefore, it is urgent to develop a material constitutive calculation method that can effectively improve the numerical stability and implicit iterative convergence of the GTN model in the low porosity stage without altering its fundamental yield function. Summary of the Invention
[0005] This application provides a constitutive calculation method, apparatus, device, and medium for improving the GTN model, aiming to solve the technical problem that the numerical iteration of the traditional GTN model diverges and fails to converge due to the appearance of negative porosity during the numerical iteration process.
[0006] In a first aspect, embodiments of this application provide a constitutive calculation method for improving a GTN model, comprising: In the implicit finite element method calculation, the initial porosity of the target material in the current increment step is obtained; Determine whether the initial porosity is greater than a preset minimum porosity threshold; If the initial porosity is greater than the preset minimum porosity threshold, then based on the preset improved GTN yield criterion, the constitutive calculation of the target material in the current increment step is completed. The preset improved GTN yield criterion is used to calculate the constitutive material parameters of the target material.
[0007] Optionally, the method further includes: If the initial porosity is less than or equal to the preset minimum porosity threshold, the Von Mises yield criterion is used to complete the constitutive calculation of the target material in the current increment step.
[0008] Optionally, if the initial porosity is greater than the preset minimum porosity threshold, then a preset improved GTN yield criterion is used to complete the constitutive calculation of the target material in the current increment step, including: If the initial porosity is greater than the preset minimum porosity threshold, then the initial stress, initial strain, and strain increment of the target material in the current increment step are obtained; The hydrostatic pressure and Mises equivalent stress of the target material are calculated based on the initial stress, the initial strain, and the strain increment, respectively. The hydrostatic pressure and the Mises equivalent stress are input into a preset improved GTN model to obtain the yield value; Determine whether the yield value is greater than a preset yield threshold; If the yield value is greater than the preset yield threshold, the return map method is used to complete the constitutive calculation of the target material in the current increment step.
[0009] Optionally, the preset improved GTN model is:
[0010] in, The yield value, For hydrostatic pressure, For Mises equivalent stress, and These are all material parameters. The yield strength when the porosity is zero. Porosity This is the porosity adjustment function. This is a material parameter function.
[0011] Optionally, the for:
[0012] in, Porosity This is the preset minimum porosity threshold.
[0013] Optionally, the for:
[0014] in, Porosity To preset the minimum porosity threshold, These are material parameters.
[0015] Optionally, if the yield value is greater than the preset yield threshold, the return map method is used to complete the constitutive calculation of the target material in the current increment step, including: Determine the Is it greater than the preset threshold? If the above If the value is greater than the preset threshold, the current incremental step is divided into multiple sub-incremental steps; The return map method is used to complete the constitutive calculation of the target material in each of the multiple sub-incremental steps.
[0016] Secondly, embodiments of this application also provide a constitutive computing apparatus for improving a GTN model, which includes a unit for performing the above-described method.
[0017] Thirdly, embodiments of this application also provide a computer device, which includes a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the above-described method.
[0018] Fourthly, embodiments of this application also provide a computer-readable storage medium storing a computer program that, when executed by a processor, can implement the above-described method.
[0019] This application provides a constitutive calculation method, apparatus, device, and medium for improving a GTN model. The method includes: obtaining the initial porosity of a target material in the current increment step during implicit finite element calculation; determining whether the initial porosity is greater than a preset minimum porosity threshold; and if the initial porosity is greater than the preset minimum porosity threshold, completing the constitutive calculation of the target material in the current increment step based on a preset improved GTN yield criterion, wherein the preset improved GTN yield criterion is used to calculate the constitutive material parameters of the target material. Therefore, the technical solution of this application first obtains the initial porosity of the target material in the current increment step during implicit finite element calculation; then determines whether the initial porosity is greater than a preset minimum porosity threshold; and finally, if the initial porosity is greater than the preset minimum porosity threshold, completes the constitutive calculation of the target material in the current increment step based on a preset improved GTN yield criterion. The preset improved GTN yield criterion is used to calculate the constitutive material parameters of the target material. Therefore, this application first performs a minimum threshold validity check on the initial porosity in the incremental step of the implicit finite element calculation. Only when the porosity meets the physical rationality requirements is the improved GTN yield criterion used to carry out material constitutive calculation. Furthermore, it ensures that the shape of the yield function changes continuously when a negative porosity value occurs during the iteration process. This solves the technical problem of numerical iteration divergence and non-convergence caused by negative porosity in the traditional GTN model, and achieves stable and reliable calculation of material constitutive properties. Attached Figure Description
[0020] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.
[0021] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0022] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.
[0023] Figure 1 A flowchart illustrating a constitutive calculation method for improving a GTN model, provided as an embodiment of this application; Figure 2 A flowchart of a GTN model material subroutine provided for an embodiment of this application; Figure 3 This application provides an embodiment of the yield function shape of the GTN model before and after adjustment; Figure 4 Hydrostatic pressure before and after adjustment for the GTN model provided in the embodiments of this application p Schematic diagram of the curve of porosity f; Figure 5 Mises stress before and after adjustment in the GTN model provided in the embodiments of this application q Schematic diagram of the curve of porosity f; Figure 6a A schematic diagram illustrating the non-convergence result obtained by using ABAQUS software with the GTN model in an embodiment of this application; Figure 6b This is a schematic diagram illustrating the convergence results obtained by using WeICME with a preset improved GTN model in an embodiment of this application. Figure 7 Porosity results of a pre-defined improved GTN model for hot isostatic pressing simulation of a turbine blade containing shrinkage cavities and porosity provided in the embodiments of this application; Figure 8 A schematic block diagram of a constitutive computing device for improving a GTN model, provided for embodiments of this application; Figure 9 A computer device provided in an embodiment of this application. Detailed Implementation
[0024] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0025] The following disclosure provides numerous different embodiments or examples for implementing various structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed.
[0026] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.
[0027] It should also be understood that the terminology used in this application specification is for the purpose of describing particular embodiments only and is not intended to limit the application. As used in this application specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.
[0028] It should also be further understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.
[0029] As used in this specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if [described condition or event] is detected" may be interpreted, depending on the context, as "once determined," "in response to determination," "once [described condition or event] is detected," or "in response to detection of [described condition or event]."
[0030] To address the technical problem of numerical iteration divergence and non-convergence caused by negative porosity in the traditional GTN model during numerical iteration, this application provides a constitutive computing device for improving the GTN model, which solves the technical problem of numerical iteration divergence and non-convergence caused by negative porosity in the traditional GTN model.
[0031] Please see Figure 1 and Figure 2 , Figure 1 This is a flowchart illustrating a constitutive calculation method for improving a GTN model, provided as an embodiment of this application. Figure 2 A flowchart of a GTN model material subroutine is provided for an embodiment of this application. In one embodiment, the method includes: S101-S103.
[0032] S101. During the implicit finite element calculation, obtain the initial porosity of the target material in the current increment step.
[0033] In the material subroutine of the implicit finite element method, the material subroutine reads the initial porosity of the target material in the current increment step. The target material includes, but is not limited to, porous or shrinkage-filled metallic materials.
[0034] S102. Determine whether the initial porosity is greater than the preset minimum porosity threshold.
[0035] The preset minimum porosity threshold is set based on practical experience. This application does not impose any restrictions on this setting. Preferably, the preset minimum porosity threshold is 0.
[0036] S103. If the initial porosity is greater than the preset minimum porosity threshold, then the constitutive calculation of the target material in the current increment step is completed based on the preset improved GTN yield criterion.
[0037] The preset improved GTN yield criterion is used to calculate the constitutive material parameters of the target material. Specifically, the preset improved GTN yield criterion is used to maintain the continuous change of the yield surface shape when the porosity changes from a positive value to a negative value during the iteration process. The constitutive material parameters include, but are not limited to, stress, strain, porosity, and the material tangent stiffness matrix.
[0038] This application provides a constitutive calculation method for improving a GTN model. The method includes: obtaining the initial porosity of the target material in the current increment step during the implicit finite element method (FEM) calculation; determining whether the initial porosity is greater than a preset minimum porosity threshold; and if the initial porosity is greater than the preset minimum porosity threshold, completing the constitutive calculation of the target material in the current increment step based on a preset improved GTN yield criterion, wherein the preset improved GTN yield criterion is used to calculate the constitutive material parameters of the target material. Therefore, the technical solution of this application first obtains the initial porosity of the target material in the current increment step during the implicit finite element method (FEM) calculation; then, determines whether the initial porosity is greater than a preset minimum porosity threshold; and finally, if the initial porosity is greater than the preset minimum porosity threshold, completes the constitutive calculation of the target material in the current increment step based on the preset improved GTN yield criterion. The preset improved GTN yield criterion is used to calculate the constitutive material parameters of the target material. Therefore, this application first performs a minimum threshold validity check on the initial porosity in the incremental step of the implicit finite element calculation. Only when the porosity meets the physical rationality requirements is the improved GTN yield criterion used to carry out material constitutive calculation. Furthermore, it ensures that the shape of the yield function changes continuously when a negative porosity value occurs during the iteration process. This solves the technical problem of numerical iteration divergence and non-convergence caused by negative porosity in the traditional GTN model, and achieves stable and reliable calculation of material constitutive properties.
[0039] In one embodiment, the method further includes: S104.
[0040] S104. If the initial porosity is less than or equal to the preset minimum porosity threshold, the Von Mises yield criterion is adopted to complete the constitutive calculation of the target material in the current increment step.
[0041] Among them, the Von Mises yield criterion is the most widely used yield criterion for isotropic metallic materials.
[0042] It should be noted that this application uses the return map method to calculate the stress, strain, and tangential stiffness matrix of the target material according to the Von Mises yield criterion. The return map method (often called the reflection method or mapping back-transmission method) is a core implicit integral algorithm for plastic correction in elastoplastic finite element numerical analysis, and a classic method for handling elastoplastic deformation in implicit finite element calculations. Its core function is to reflect (pull back) the super-yield surface stress obtained from elastic calculations to the material's yield surface along the plastic flow direction, obtaining the true elastoplastic stress state that satisfies the yield criterion, while simultaneously completing accurate updates of plastic strain and internal state variables.
[0043] In one embodiment, S103 specifically includes S1031-S1036.
[0044] S1031. If the initial porosity is greater than the preset minimum porosity threshold, then obtain the initial stress, initial strain, and strain increment of the target material in the current increment step.
[0045] It should be noted that in the implicit finite element calculation process, the initial stress, initial strain, and strain increment of the current increment step are obtained at the integration point.
[0046] S1032. Based on the initial stress, initial strain, and strain increment, the hydrostatic pressure and Mises equivalent stress of the target material are calculated respectively.
[0047] It should be noted that the hydrostatic pressure of the target material is calculated based on the initial stress, initial strain, and strain increment, and the Mises equivalent stress of the target material is also calculated based on the initial stress, initial strain, and strain increment. The specific calculation process is prior art, and will not be elaborated here.
[0048] S1033. Input the hydrostatic pressure and Mises equivalent stress into the preset improved GTN model to obtain the yield value.
[0049] The yield value is also called the yield function value.
[0050] The preset improved GTN model is as follows:
[0051] in, The yield value, For hydrostatic pressure, For Mises equivalent stress, and These are all material parameters. The yield strength when the porosity is zero. Porosity This is the porosity adjustment function. This is a material parameter function.
[0052] It should be noted that, physically, porosity Negative values are impossible, but porosity is calculated from plastic strain during simulation, which may result in negative values.
[0053] Porosity adjustment function, porosity smaller ( The closer the yield surface approaches 0, the more the minor axis of the yield surface ( q The yield strength of the shaft in a dense state ( σ y Within ) , under the condition that the above conditions are met ( ) can take many forms of continuous functions.
[0054] It is a material parameter function, and f smaller The closer it is to 0, that is, the longer the yield surface axis ( p The axis tends towards infinity, provided the above conditions are met. Continuous functions can take many forms.
[0055] In one embodiment, the for:
[0056] in, Porosity This is the preset minimum porosity threshold.
[0057] It should be noted that porosity It can be a negative number, and f Smaller function ( The closer the yield strength is to 0. In other words, the yield strength in the dense state is always at the point where the minor axis (q-axis) of the yield surface is always close to 0. σ y Within 100%. Under the condition that the above conditions are met... ( ) can be a continuous function in various forms. One of them can be defined as a piecewise function, which is used when the porosity is greater than or equal to a preset minimum porosity threshold. min Take the current porosity f When the porosity is less than min Take the preset minimum porosity threshold min .
[0058] In one embodiment, the for:
[0059] in, Porosity To preset the minimum porosity threshold, These are material parameters.
[0060] Porosity It can be a negative number, and Smaller function The closer it gets to 0, the closer the major axis of the yield surface (p-axis) approaches infinity. Under the condition that the above conditions are met... Various forms of continuous functions can be used. One such function can be defined as a piecewise function that varies with porosity, where the porosity is less than a preset minimum porosity threshold. At that time, for the parameters corresponding to the hyperbolic function terms in the GTN model Reduce the amount.
[0061] S1034. Determine whether the yield value is greater than the preset yield threshold. If yes, proceed to S1035; otherwise, proceed to S1036.
[0062] The preset yield threshold is set based on practical experience. This application does not impose any restrictions on this setting. Preferably, the preset yield threshold is 0.
[0063] S1035. Using the return map method, complete the constitutive calculation of the target material in the current increment step.
[0064] It should be noted that the return map method has been described in detail in the above embodiments. Therefore, it will not be repeated here.
[0065] S1036. According to the elasticity theory, complete the constitutive calculation of the target material in the current increment step.
[0066] Specifically, if the target material does not yield, the stress, strain, and tangential stiffness matrix of the material are calculated according to elasticity theory.
[0067] In one embodiment, S1035 specifically includes the following steps: S10351-S10353.
[0068] S10351, Judgment Is it greater than the preset threshold?
[0069] S10352, if If the value exceeds a preset threshold, the current increment step will be divided into multiple sub-increment steps.
[0070] In this process, each of the multiple sub-incremental steps is less than or equal to a preset threshold. Preferably, the preset threshold is 1×10-1. 100 .
[0071] S10353. Using the return map method, complete the constitutive calculation of the target material in each of the multiple sub-incremental steps.
[0072] It should be noted that S10351-S10353 will be explained in detail below.
[0073] When calculating the yield equation, Too large a value will cause the program to overflow. Therefore, it is necessary to... Keep it within a reasonable range. Greater than a preset threshold (for example, the preset threshold is 1×10). 100 When performing implicit finite element method (FEM) calculations, the current increment step can be divided into multiple sub-increment steps, and the constitutive material parameters can be iteratively calculated using a step-by-step accumulation method. For example, in the entire FEM implicit calculation process, the simulation time is 0-1 seconds. If the FEM calculation is divided into 0.1-second increments, then the current increment step span is 0.1 seconds (e.g., 0.2-0.3 seconds). If the cosh function is too large, the current increment step of 0.1 seconds is divided into several sub-increment steps to ensure that the cosh function is less than a threshold in each sub-increment step, for example: 0.2-0.21, 0.21-0.22, ..., 0.28-0.29. Then, the constitutive material parameters of the target material are iteratively calculated using a step-by-step accumulation method. If the cosh function is too large in a certain sub-increment step, the sub-increment step is further divided into multiple sub-sub-increment steps until the cosh function in all sub-sub-increment steps is less than or equal to a preset threshold.
[0074] Figure 3 This application provides an embodiment of the yield function shape of a GTN model before and after adjustment. The model parameters are set as follows: q 1= q 2= q 3=1, σ y =1 MPa f min=0.0001. It can be seen that when the porosity is less than the threshold of 0.0001, the yield surfaces of the two models are consistent. However, when the porosity is less than or equal to 0, the adjusted model can still maintain the same shape as the original model, while the original model becomes a straight line and an upward-curving curve, which makes convergence difficult when using Newton's iteration method.
[0075] Please see Figure 4 and Figure 5 . Figure 4 Hydrostatic pressure before and after adjustment for the GTN model provided in the embodiments of this application p A schematic diagram of the curves showing the change in porosity f. Figure 5 Mises stress before and after adjustment in the GTN model provided in the embodiments of this application q A schematic diagram showing the curve of porosity f. Figure 4 It can be seen that the original model has a porosity f hydrostatic pressure less than 0 p The absence of a value is the main reason why the iteration fails to converge. Figure 5 It can be seen that Mises stress q This would exceed the yield strength in the dense state. σ y The adjusted model can guarantee hydrostatic pressure. p It can converge to a fixed porosity value. Although this porosity may be negative, the negative value will not be too small after iterative convergence and will still be near 0. Furthermore, in the next incremental step, it will be judged as dense according to S102 above, and the Mises yield criterion will be used for subsequent calculations, without further reducing the porosity.
[0076] Figure 6a This illustration shows a non-convergence result obtained by using the GTN model with ABAQUS software in an embodiment of this application. Figure 6b This diagram illustrates the convergence results obtained using the WeICME software and a preset improved GTN model, as described in an embodiment of this application. Specifically, it is set to... q 1= q 2= q 3=1, σ y =1 MPa f min =0.0001, f 0=0.1, load pressure is 10MPa. ABAQUS cannot calculate a convergent result; the porosity in the last step before termination is approximately 0.05. Figure 6a As shown. The adjusted model successfully completed the calculation, with the porosity almost zero after compression, as shown. Figure 6b As shown.
[0077] Figure 7The porosity results of a turbine blade with shrinkage cavities provided in this application embodiment are obtained through hot isostatic pressing simulation using a preset improved GTN model. The simulation shows that the hot isostatic pressing process can essentially eliminate the blade porosity.
[0078] See Figure 8 , Figure 8 This is a schematic block diagram of a constitutive computing device for improving a GTN model, provided in an embodiment of this application. Corresponding to the above-described constitutive computing method for improving a GTN model, this application also provides a constitutive computing device for improving a GTN model. This constitutive computing device for improving a GTN model includes a unit for executing the above-described constitutive computing method for improving a GTN model, and can be configured in a terminal such as a desktop computer, tablet computer, or laptop computer. Specifically, the constitutive computing device for improving a GTN model includes: Acquisition unit 801 is used to acquire the initial porosity of the target material in the current increment step during the implicit finite element calculation process; The judgment unit 802 is used to determine whether the initial porosity is greater than a preset minimum porosity threshold. The completion unit 803 is used to complete the constitutive calculation of the target material in the current increment step based on the preset improved GTN yield criterion if the initial porosity is greater than the preset minimum porosity threshold. The preset improved GTN yield criterion is used to calculate the constitutive material parameters of the target material.
[0079] In one embodiment, the completion unit 803 is further configured to: If the initial porosity is less than or equal to the preset minimum porosity threshold, the Von Mises yield criterion is used to complete the constitutive calculation of the target material in the current increment step.
[0080] In one embodiment, the completion unit 803 is specifically used for: If the initial porosity is greater than the preset minimum porosity threshold, then the initial stress, initial strain, and strain increment of the target material in the current increment step are obtained; The hydrostatic pressure and Mises equivalent stress of the target material are calculated based on the initial stress, the initial strain, and the strain increment, respectively. The hydrostatic pressure and the Mises equivalent stress are input into a preset improved GTN model to obtain the yield value; Determine whether the yield value is greater than a preset yield threshold; If the yield value is greater than the preset yield threshold, the return map method is used to complete the constitutive calculation of the target material in the current increment step.
[0081] In one embodiment, the preset improved GTN model is:
[0082] in, The yield value, For hydrostatic pressure, For Mises equivalent stress, and These are all material parameters. The yield strength when the porosity is zero. Porosity This is the porosity adjustment function. This is a material parameter function.
[0083] In one embodiment, the for:
[0084] in, Porosity This is the preset minimum porosity threshold.
[0085] In one embodiment, the for:
[0086] in, Porosity To preset the minimum porosity threshold, These are material parameters.
[0087] In one embodiment, the completion unit 803 is specifically used for: Determine the Is it greater than the preset threshold? If the above If the value is greater than the preset threshold, the current incremental step is divided into multiple sub-incremental steps; The return map method is used to complete the constitutive calculation of the target material in each of the multiple sub-incremental steps.
[0088] like Figure 9 As shown, this application provides a computer device including a processor 91, a communication interface 92, a memory 93, and a communication bus 94. The processor 91, the communication interface 92, and the memory 93 communicate with each other through the communication bus 94. The memory 93 is used to store computer programs. In one embodiment of this application, when the processor 91 executes the program stored in the memory 93, it implements the control method for improving the constitutive calculation of the GTN model provided in any of the foregoing method embodiments.
[0089] It will be understood by those skilled in the art that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program may be stored in a storage medium, which is a computer-readable storage medium. The computer program is executed by at least one processor in the computer system to implement the process steps of the embodiments of the above methods.
[0090] Therefore, embodiments of this application also provide a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the constitutive calculation method for improving the GTN model as provided in any of the foregoing method embodiments.
[0091] The storage medium is a physical, non-transient storage medium, such as a USB flash drive, external hard drive, read-only memory (ROM), magnetic disk, or optical disk, or any other physical storage medium capable of storing program code. The computer-readable storage medium can be non-volatile or volatile.
[0092] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this application.
[0093] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative. For example, the division of each unit is merely a logical functional division, and there may be other division methods in actual implementation. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed.
[0094] The steps in the methods of this application embodiment can be adjusted, merged, or deleted according to actual needs. The units in the apparatus of this application embodiment can be merged, divided, or deleted according to actual needs. Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.
[0095] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, a terminal, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application.
[0096] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.
[0097] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Since these modifications and variations fall within the scope of the claims and their equivalents, this application also intends to include these modifications and variations.
[0098] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.
Claims
1. A constitutive calculation method for improving GTN models, characterized in that, include: In the implicit finite element method calculation, the initial porosity of the target material in the current increment step is obtained; Determine whether the initial porosity is greater than a preset minimum porosity threshold; If the initial porosity is greater than the preset minimum porosity threshold, then based on the preset improved GTN yield criterion, the constitutive calculation of the target material in the current increment step is completed. The preset improved GTN yield criterion is used to calculate the constitutive material parameters of the target material.
2. The method according to claim 1, characterized in that, The method further includes: If the initial porosity is less than or equal to the preset minimum porosity threshold, the Von Mises yield criterion is used to complete the constitutive calculation of the target material in the current increment step.
3. The method according to claim 1, characterized in that, If the initial porosity is greater than the preset minimum porosity threshold, then a preset improved GTN yield criterion is used to complete the constitutive calculation of the target material in the current increment step, including: If the initial porosity is greater than the preset minimum porosity threshold, then the initial stress, initial strain, and strain increment of the target material in the current increment step are obtained; The hydrostatic pressure and Mises equivalent stress of the target material are calculated based on the initial stress, the initial strain, and the strain increment, respectively. The hydrostatic pressure and the Mises equivalent stress are input into a preset improved GTN model to obtain the yield value; Determine whether the yield value is greater than a preset yield threshold; If the yield value is greater than the preset yield threshold, the return map method is used to complete the constitutive calculation of the target material in the current increment step.
4. The method according to claim 3, characterized in that, The preset improved GTN model is: in, The yield value, For hydrostatic pressure, For Mises equivalent stress, and These are all material parameters. The yield strength when the porosity is zero. Porosity This is the porosity adjustment function. This is a material parameter function.
5. The method according to claim 4, characterized in that, The for: in, Porosity This is the preset minimum porosity threshold.
6. The method according to claim 4, characterized in that, The for: in, Porosity To preset the minimum porosity threshold, These are material parameters.
7. The method according to claim 4, characterized in that, If the yield value is greater than the preset yield threshold, the return map method is used to complete the constitutive calculation of the target material in the current increment step, including: Determine the Is it greater than the preset threshold? If the above If the value is greater than the preset threshold, the current incremental step is divided into multiple sub-incremental steps; The return map method is used to complete the constitutive calculation of the target material in each of the multiple sub-incremental steps.
8. A constitutive computational apparatus for improving GTN models, characterized in that, include: The acquisition unit is used to acquire the initial porosity of the target material in the current increment step during the implicit finite element calculation process. The judgment unit is used to determine whether the initial porosity is greater than a preset minimum porosity threshold. The completion unit is used to complete the constitutive calculation of the target material in the current increment step based on a preset improved GTN yield criterion if the initial porosity is greater than the preset minimum porosity threshold. The preset improved GTN yield criterion is used to calculate the constitutive material parameters of the target material.
9. A computer device, characterized in that, The computer device includes a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the method as described in any one of claims 1 to 7.
10. A computer-readable storage medium, characterized in that, The storage medium stores a computer program that, when executed by a processor, can implement the method as described in any one of claims 1 to 7.