Strain rate based phase field stress corrosion cracking simulation method, system and apparatus

Abstract

This invention provides a method, system, and apparatus for simulating phase-field stress corrosion cracking (SCC) based on strain rate, belonging to the field of SCC simulation technology. The method includes: constructing a finite element model based on sample information and boundary conditions, obtaining a finite element output file; constructing a phase-field model, which includes variables, input parameters, free energy functionals, and governing equations; solving the governing equations based on the finite element output file; and obtaining convergent solutions of the variables through the phase-field model based on different strain rates, obtaining a result file. This scheme can simulate the initiation and propagation of SCC cracks in metals at the micrometer scale. By comparing the crack initiation time, crack propagation morphology, and crack propagation rate values ​​under different strain rates, it guides the design of SCC experimental design for novel alloy compositions, thereby improving evaluation efficiency.

Description

Technical Field

[0001] This invention relates to the field of phase field stress corrosion cracking simulation technology, and in particular to a method, system and apparatus for simulating phase field stress corrosion cracking based on strain rate. Background Technology

[0002] Metals such as aluminum alloys are highly susceptible to stress corrosion cracking (SCC), which limits their engineering applicability and service safety in harsh environments.

[0003] To assess the SCC susceptibility of metals such as aluminum alloys, slow strain rate tensile (SSRT) tests are typically used. Depending on the specific testing standard, a single strain rate is usually selected for aluminum alloys. To demonstrate the mechanical and electrochemical coupling phenomena during stress corrosion cracking (SCC), different strain rates should be selected for aluminum alloys with different compositions during SSRT testing. The optimal strain rate for reflecting the SCC process should be chosen by comparing the SSRT curves of samples in air and corrosive media. Furthermore, different strain rates are closely related to crack initiation and propagation during stress corrosion cracking.

[0004] With the development of simulation technology, it has become possible to simulate the mechanical and electrochemical coupling effects of the strain-induced cracking (SCC) process. However, existing simulation methods typically use strain hardening rate to describe the hardening effect caused by strain rate, and are mainly applied to fracture under single stress, without considering the influence of electrochemical coupling. Summary of the Invention

[0005] The purpose of this invention is to provide a method, system, and apparatus for simulating phase field stress corrosion cracking based on strain rate, so as to solve at least one of the above-mentioned technical problems existing in the prior art.

[0006] In a first aspect, to solve the above-mentioned technical problems, the present invention provides a phase field stress corrosion cracking simulation method based on strain rate, comprising the following steps:

[0007] Step 1: Based on the sample information and boundary conditions, construct the finite element model (using the finite element command flow program) and obtain the finite element output file.

[0008] In one feasible implementation, the sample information includes the matrix size and crack size; the crack size is the average size of pitting pits obtained from the SSRT test.

[0009] In one feasible implementation, the boundary conditions include fixed displacement boundary constraints, specified displacement boundary constraints, and a solid-liquid interface; the solid-liquid interface is located at the crack; thus, both the metal dissolution caused by electrolytes and the material degradation caused by metal damage due to mechanical action are taken into account, effectively revealing the evolution process driven by both electrochemistry and mechanics at the crack on the metal surface in the SSRT test.

[0010] In one feasible implementation, the finite element output file includes the total number of nodes, the total number of elements, the number of degrees of freedom, the element type, the number of Gaussian points, the node position information at the solid-liquid interface, the number of constrained nodes, and the degree of freedom information at the constraint points.

[0011] Step 2: Construct a phase-field model; the phase-field model includes variables, input parameters, free energy functionals, and governing equations; the governing equations include the Cahn-Hilliard equation controlled by the concentration field, the Allen-Cahn equation controlled by the phase field, and the displacement finite element equation controlled by the displacement field.

[0012] In one feasible implementation, the phase-field model is implemented using the MATLAB language.

[0013] In one feasible implementation, the variables of the phase-field model include: strain energy, stress, and concentration. Sum of parameters Among them, when , When, it corresponds to the solid phase; when , When, it corresponds to the liquid phase; when At that time, corresponding to the corrosion boundary, the specific value range can be... The concentration It is the concentration after the sample material composition has been normalized.

[0014] In one feasible implementation, the input parameters of the phase-field model include sample material parameters and time integration parameters; the sample material parameters include known or calculable parameters such as free energy density curvature, diffusion coefficient, metal atom concentration, saturation concentration of metal ions, elastic modulus of the solid phase, virtual elastic modulus of the liquid phase, Poisson's ratio, interface thickness, and interface dynamic parameters; the time integration parameters include the total time step (i.e., the total length of physical time) and the output step (i.e., the time interval).

[0015] In one feasible implementation, the interface kinetic parameters are obtained by conventional calculation based on the corrosion current density measured by the SSRT test and the proportional relationship between the interface kinetic parameters and the corrosion current density.

[0016] In one feasible implementation, the specific expression of the free energy functional includes:

[0017] ;

[0018] in, Represents the total free energy; Specific expressions for chemical free energy, including chemical free energy density, include:

[0019] ;in, Represents the local chemical energy density of a solid metal; Represents the local chemical energy density of a liquid; Represents a degenerate function;

[0020] Specific expressions representing surface energy, including surface energy density, include:

[0021] ;in, The gradient of the order parameter; Represents the gradient energy coefficient. This represents the height of the applied double-well barrier, which can be obtained through interfacial energy. and the interface thickness of the anodic dissolution model The results were obtained through fitting. Let represent a double-well potential, and we have: ;

[0022] Indicates strain energy; Indicates displacement.

[0023] In one feasible implementation, the specific expression of the Cahn-Hilliard equation includes:

[0024] ;

[0025] ;

[0026] in, Indicates about The trial function; Indicates about The trial function; Indicates ion mobility; This represents the total free energy density of the system; Indicates displacement; Indicates time; Indicates the interface dynamics parameters; The first derivative of the degenerate function; The first derivative of the double-well potential is expressed. This represents a history function related to strain, used to process the loading process;

[0027] Therefore, the Cahn-Hilliard equation at this point is a parabolic equation involving first-order time derivatives and second-order (or fourth-order) spatial derivatives. Directly converting it to a weak form would result in the existence of second-order spatial derivatives, requiring special finite elements with higher-order shape functions (such as C1 continuous cubic Hermite elements), thus significantly increasing the computational workload. Therefore, it is rearranged into two coupled second-order equations in the region... The integrals are as follows:

[0028] ;

[0029] ;

[0030] in, Indicates intermediate variables; Represents chemical free energy density; Indicates the gradient energy coefficient;

[0031] Thus, the unknown now becomes and Therefore, the concentration-related degrees of freedom at the element nodes also become two, thus allowing the use of the standard isoparametric element (commonly the finite element) with high computational efficiency and sufficient accuracy. Combined with Green's formula, the weak form of the effective integral equation is obtained as follows:

[0032] ;

[0033] ;

[0034] in, Indicates the time step number;

[0035] Thus, the subsequent sequence passes through two adjacent time steps. and The difference between them can be used to solve for the intermediate variable. And the Cahn-Hilliard equation.

[0036] Step 3: Solve the governing equations based on the finite element output file; based on different strain rates, obtain the convergent solution of the variables through the phase field model, and obtain the result file.

[0037] In one feasible implementation, in step 3, the Cahn-Hilliard equation, used to describe ion diffusion in the stress corrosion cracking process, is solved using the Newton-Raphson method through conventional iterative methods; the Allen-Cahn equation, used to describe interface movement caused by metal dissolution, is solved using time discretization and semi-implicit Euler integrals; and the displacement finite element equation, used to describe the stress state of the material, is solved using conventional methods by establishing a global stiffness matrix and a global force vector.

[0038] In one feasible implementation, the global force vector includes a strain rate scaling factor.

[0039] In one feasible implementation, the strain rate includes , , and .

[0040] In one feasible implementation, the phase field stress corrosion cracking simulation method further includes step 4, which involves visualizing the result files with different total time steps to obtain the variable values ​​at the solid-liquid interface under the corresponding total time step and performing cracking analysis.

[0041] In one feasible implementation, the specific method for crack analysis includes: obtaining the crack propagation rate through differential calculation; collecting the crack tip stress and strain energy values ​​at crack initiation; comparing the changes in crack propagation rate, crack tip stress, and strain energy values ​​under different strain rates, and making a determination.

[0042] When the stress at the crack tip exceeds the yield strength, the cracking is determined to be mechanically caused.

[0043] When the stress at the crack tip is less than the yield strength, the crack is determined to be caused by both mechanical and electrochemical factors.

[0044] Secondly, based on the same inventive concept, this application also provides a phase field stress corrosion cracking simulation system based on strain rate, including a data acquisition module, a data processing module and a result generation module;

[0045] The data acquisition module is used to collect sample information;

[0046] The data processing module includes finite element model units, phase field model units, and solution units;

[0047] The finite element model unit is used to construct a finite element model based on sample information and boundary conditions, and obtain a finite element output file.

[0048] The phase-field model unit is used to construct the phase-field model; the phase-field model includes variables, input parameters, free energy functionals, and governing equations; the governing equations include the Cahn-Hilliard equation controlled by the concentration field, the Allen-Cahn equation controlled by the phase field, and the displacement finite element equation controlled by the displacement field.

[0049] The solving unit is used to solve the governing equations based on the finite element output file; based on different strain rates, it obtains the convergent solution of the variables through the phase field model and obtains the result file.

[0050] The result generation module is used to send the processing results of the solving unit to external systems.

[0051] In one feasible implementation, the solving unit also performs visualization processing on the result files with different total time steps to obtain the variable values ​​at the solid-liquid interface under the corresponding total time step and performs crack analysis.

[0052] Thirdly, based on the same inventive concept, this application also provides a phase field stress corrosion cracking simulation device based on strain rate, including a processor, a memory, and a bus. The memory stores instructions and data that can be read by the processor. The processor is used to call the instructions and data in the memory to execute the phase field stress corrosion cracking simulation method as described above. The bus connects the functional components for transmitting information.

[0053] By adopting the above technical solution, the present invention has the following beneficial effects:

[0054] This invention provides a phase field stress corrosion cracking simulation method, system, and apparatus based on strain rate. Based on phase field simulation calculation, it can simulate the initiation and propagation of SCC cracks in metals at the micrometer scale. By comparing the crack initiation time, crack propagation morphology, and crack propagation rate (plateau period) under different strain rates, it can guide the design of SSRT experiments for novel alloy compositions, thereby improving the evaluation efficiency for different strain rate selections. Attached Figure Description

[0055] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0056] Figure 1 A flowchart of a phase field stress corrosion cracking simulation method based on strain rate is provided for an embodiment of the present invention;

[0057] Figure 2 A schematic diagram of a sample geometric model including boundary conditions provided in an embodiment of the present invention;

[0058] Figure 3 Comparison of crack propagation under two conditions, with and without load, provided for embodiments of the present invention;

[0059] Figure 4 The following are output distribution cloud maps provided for embodiments of the present invention during crack propagation; wherein, (a) is a concentration distribution cloud map; (b) is a strain energy distribution cloud map; (c) is a sequence parameter distribution cloud map; (d) is an X-direction stress distribution cloud map; (e) is a Y-direction stress distribution cloud map; and (f) is an XY-direction stress distribution cloud map.

[0060] Figure 5 The crack propagation rate versus time at different strain rates is provided in the embodiments of the present invention; wherein, (a) is The following is a change diagram; (b) is a diagram showing the changes. The following is a change diagram; (c) is a diagram showing the changes. The following is a change graph; (d) is a graph showing the changes. The following is a change graph;

[0061] Figure 6 The figures provided in this embodiment of the invention are a comparison of the surface morphology of the crack after the SSRT test and the simulation results; wherein, (a) is a microscopic image of the crack; (b) is an enlarged view of (a); and (c) is a simulation result.

[0062] Figure 7 A diagram of a phase field stress corrosion cracking simulation system based on strain rate is provided for an embodiment of the present invention. Detailed Implementation

[0063] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0064] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0065] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0066] The present invention will be further explained below with reference to specific embodiments.

[0067] It should also be noted that the specific embodiments or implementation methods described below are a series of optimized settings listed by the present invention to further explain the specific content of the invention, and these settings can be combined or used in conjunction with each other.

[0068] Example 1:

[0069] like Figure 1 As shown in the figure, this embodiment provides a phase field stress corrosion cracking simulation method based on strain rate, which includes the following steps:

[0070] Step 1: Based on the sample information and boundary conditions, construct the finite element model (using the finite element command flow program) and obtain the finite element output file.

[0071] Furthermore, the sample information includes the matrix size and crack size; the crack size is the average size of pitting corrosion obtained from the SSRT test. Figure 2 As shown, in this embodiment, the cross-section of the substrate is a rectangle with a length of 200μm and a width of 160μm; at the midpoint on the left side of the rectangle, a crack defect with a length and width of 6μm is prefabricated.

[0072] Furthermore, the boundary conditions include fixed displacement boundary constraints, specified displacement boundary constraints, and a solid-liquid interface; the solid-liquid interface is located at the crack. This simultaneously addresses both metal dissolution caused by electrolytes and material degradation due to metal damage caused by mechanical forces, effectively revealing the evolution process driven by both electrochemistry and mechanics at the metal surface crack in the SSRT test. In this embodiment, the lower boundary of the rectangle is set as a fixed displacement boundary constraint, a specified displacement boundary constraint is applied to the upper boundary of the rectangle, and the strain rate is set using a scaling factor.

[0073] Furthermore, the finite element output file includes the total number of nodes, the total number of elements, the number of degrees of freedom, the element type, the number of Gaussian points, the node position information at the solid-liquid interface, the number of constrained nodes, and the degree of freedom information at the constraint points.

[0074] Step 2: Construct a phase-field model; the phase-field model includes variables, input parameters, free energy functionals, and governing equations; the governing equations include the Cahn-Hilliard equation controlled by the concentration field, the Allen-Cahn equation controlled by the phase field, and the displacement finite element equation controlled by the displacement field.

[0075] Furthermore, the phase-field model is implemented using the MATLAB language.

[0076] Furthermore, the variables in the phase-field model include: strain energy, stress, and concentration. Sum of parameters Among them, when , When, it corresponds to the solid phase; when , When, it corresponds to the liquid phase; when At that time, corresponding to the corrosion boundary, the specific value range can be... The concentration It is the concentration after the sample material composition has been normalized.

[0077] Furthermore, the input parameters of the phase-field model include sample material parameters and time integration parameters; the sample material parameters include free energy density curvature, diffusion coefficient, metal atom concentration, saturation concentration of metal ions, elastic modulus of the solid phase, virtual elastic modulus of the liquid phase, Poisson's ratio, interface thickness, and interface kinetic parameters.

[0078] Furthermore, the interface kinetic parameters are obtained through conventional calculations based on the ratio between the interface kinetic parameters and the corrosion current density, after the corrosion current density is measured by the SSRT test.

[0079] In this embodiment, the sample material is 7N01 aluminum alloy, and its sample material parameters are shown in Table 1.

[0080] Table 1

[0081]

[0082] Furthermore, the specific expression of the free energy functional includes:

[0083] ;

[0084] in, Represents the total free energy; Specific expressions for chemical free energy, including chemical free energy density, include:

[0085] ;in, Represents the local chemical energy density of a solid metal; Represents the local chemical energy density of a liquid; Represents a degenerate function;

[0086] Specific expressions representing surface energy, including surface energy density, include:

[0087] ;in, The gradient of the order parameter; Represents the gradient energy coefficient. This represents the height of the applied double-well barrier, which can be obtained through interfacial energy. and the interface thickness of the anodic dissolution model The results were obtained through fitting. Let represent a double-well potential, and we have: ;

[0088] Indicates strain energy; Indicates displacement.

[0089] Furthermore, the specific expression of the Cahn-Hilliard equation includes:

[0090] ;

[0091] ;

[0092] in, Indicates about The trial function; Indicates about The trial function; Indicates ion mobility; This represents the total free energy density of the system; Indicates displacement; Indicates time; Indicates the interface dynamics parameters; The first derivative of the degenerate function; The first derivative of the double-well potential is expressed. This represents a history function related to strain, used to process the loading process;

[0093] Therefore, the Cahn-Hilliard equation at this point is a parabolic equation involving first-order time derivatives and second-order (or fourth-order) spatial derivatives. Directly converting it to a weak form would result in the existence of second-order spatial derivatives, requiring special finite elements with higher-order shape functions (such as C1 continuous cubic Hermite elements), thus significantly increasing the computational workload. Therefore, it is rearranged into two coupled second-order equations in the region... The integrals are as follows:

[0094] ;

[0095] ;

[0096] in, Indicates intermediate variables; Represents chemical free energy density; Indicates the gradient energy coefficient;

[0097] Thus, the unknown now becomes and Therefore, the concentration-related degrees of freedom at the element nodes also become two, thus allowing the use of the standard isoparametric element (commonly the finite element) with high computational efficiency and sufficient accuracy. Combined with Green's formula, the weak form of the effective integral equation is obtained as follows:

[0098] ;

[0099] ;

[0100] in, Indicates the time step number;

[0101] Thus, the subsequent sequence passes through two adjacent time steps. and The difference between them can be used to solve for the intermediate variable. And the Cahn-Hilliard equation.

[0102] Step 3: Solve the governing equations based on the finite element output file; based on different strain rates, obtain the convergent solution of the variables through the phase field model, and obtain the result file.

[0103] Furthermore, in step 3, the Cahn-Hilliard equation, used to describe ion diffusion in the stress corrosion cracking process, is solved iteratively using the Newton-Raphson method; the Allen-Cahn equation, used to describe interface movement caused by metal dissolution, is solved using time discretization and semi-implicit Euler integrals; and the displacement finite element equation, used to describe the stress state of the material, is solved by establishing a global stiffness matrix and a global force vector.

[0104] Furthermore, the global force vector includes a strain rate scaling factor.

[0105] Furthermore, the strain rate includes , , and .

[0106] Furthermore, the phase field stress corrosion cracking simulation method also includes step 4, which involves visualizing the result files with different total time steps to obtain the variable values ​​at the solid-liquid interface under the corresponding total time step and performing cracking analysis.

[0107] Furthermore, the specific method for crack analysis includes: obtaining the crack propagation rate through differential calculation; collecting the crack tip stress and strain energy values ​​at crack initiation; comparing the changes in crack propagation rate, crack tip stress, and strain energy values ​​under different strain rates, and making a judgment.

[0108] When the stress at the crack tip exceeds the yield strength, the cracking is determined to be mechanically caused.

[0109] When the stress at the crack tip is less than the yield strength, the crack is determined to be caused by both mechanical and electrochemical factors.

[0110] In this embodiment, Figure 3 The morphological evolution of the semi-circular crack is shown with and without external load. The change in crack length exhibits an exponential relationship with the total time step; specifically, without external load (pink spherical chain in the figure), the exponent is approximately 0.5, and at a strain rate of [missing information], [missing information]. Under an applied load (purple ball chain in the figure), the exponent increases significantly, approximately eight times that of the case without an applied load.

[0111] Figure 4 The diagram illustrates the output distribution of the sample during crack propagation in this embodiment. Figure (a) shows the concentration distribution cloud map; (b) shows the strain energy distribution cloud map; (c) shows the order parameter distribution cloud map; (d) shows the stress distribution cloud map in the X direction; (e) shows the stress distribution cloud map in the Y direction; and (f) shows the stress distribution cloud map in the XY direction. These figures show that the evolution of the order parameter and concentration is consistent with the stress field changes, and corrosion preferentially initiates and propagates from the crack initiation point. The maximum strain energy is located in the solid-liquid interface region near the liquid phase. Figure 4 Point A), while the maximum stress is located in the solid-liquid interface region near the solid phase (point A), Figure 4 (Point B in the middle). Compared to the crack tail region, the crack tip exhibits a higher stress concentration, thus resulting in a faster propagation rate. As the corrosion zone extends further, stress relaxation occurs in the crack tail region, causing the path of the crack dissolution zone to expand perpendicular to the direction of the external load.

[0112] Figure 5 The figure shows the crack propagation rate of the sample in this embodiment as a function of time under different strain rates; wherein, (a) is The following is a change diagram; (b) is a diagram showing the changes. The following is a change diagram; (c) is a diagram showing the changes. The following is a change graph; (d) is a graph showing the changes. The changes were plotted below; the crack length variation at different total time steps was statistically analyzed, and the crack propagation rate at that total time step could be calculated through differential operations. The results show that under high strain rate conditions ( and The crack will continue to accelerate during propagation; under low strain rate conditions ( and The crack propagation rate will plateau for a period of time.

[0113] Figure 6 The figures show a comparison between the surface morphology of the crack in the sample after the SSRT test and the simulation results; (a) is a microscopic image of the crack; (b) is an enlarged view of (a); and (c) is the simulation result. As can be seen from the figures: at a strain rate of... At this time, dissolution preferentially occurs near the pit, followed by crack initiation and further propagation along the direction perpendicular to the applied load.

[0114] Example 2:

[0115] like Figure 7 As shown, this embodiment provides a phase field stress corrosion cracking simulation system based on strain rate, including a data acquisition module, a data processing module, and a result generation module;

[0116] The data acquisition module is used to collect sample information;

[0117] The data processing module includes finite element model units, phase field model units, and solution units;

[0118] The finite element model unit is used to construct a finite element model based on sample information and boundary conditions, and a finite element output file is obtained.

[0119] The phase-field model unit is used to construct the phase-field model; the phase-field model includes variables, input parameters, free energy functionals, and governing equations; the governing equations include the Cahn-Hilliard equation controlled by the concentration field, the Allen-Cahn equation controlled by the phase field, and the displacement finite element equation controlled by the displacement field.

[0120] The solving unit is used to solve the governing equations based on the finite element output file; based on different strain rates, it obtains the convergent solution of the variables through the phase field model and obtains the result file.

[0121] The result generation module is used to send the processing results of the solving unit to external systems.

[0122] Furthermore, the solution unit also performs visualization processing on the result files with different total time steps to obtain the variable values ​​at the solid-liquid interface under the corresponding total time step and performs crack analysis.

[0123] Example 3:

[0124] This embodiment provides a phase field stress corrosion cracking simulation device based on strain rate, including a processor, a memory, and a bus. The memory stores instructions and data that can be read by the processor. The processor is used to call the instructions and data in the memory to execute the phase field stress corrosion cracking simulation method as described above. The bus connects the various functional components for information transmission.

[0125] In another embodiment, this solution can also be implemented using an integrated device, which may include corresponding modules that perform one or more steps in the various embodiments described above. A module may be one or more hardware modules specifically configured to perform the corresponding step, or implemented by a processor configured to perform the corresponding step, or stored in a computer-readable medium for implementation by a processor, or implemented through some combination thereof.

[0126] The processor executes the various methods and processes described above. For example, the method implementations in this scheme can be implemented as software programs tangibly contained in a machine-readable medium, such as memory. In some implementations, part or all of the software program can be loaded and / or installed via memory and / or a communication interface. When the software program is loaded into memory and executed by the processor, one or more steps of the methods described above can be performed. Alternatively, in other implementations, the processor can be configured to execute one of the methods described above by any other suitable means (e.g., by means of firmware).

[0127] This device can be implemented using a bus architecture. A bus architecture can include any number of interconnect buses and bridges, depending on the specific application of the hardware and overall design constraints. The bus connects various circuits, including one or more processors, memory, and / or hardware modules. The bus can also connect various other circuits such as peripherals, voltage regulators, power management circuitry, external antennas, etc.

[0128] Buses can be Industry Standard Architecture (ISA) buses, Peripheral Component Interconnect (PCI) buses, or Extended Industry Standard Component (EISA) buses, etc. Buses can be divided into address buses, data buses, control buses, etc.

[0129] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A strain rate based phase field stress corrosion cracking simulation method, characterized by, include: Step 1: Based on the sample information and boundary conditions, construct a finite element model and obtain the finite element output file; Step 2: Construct the phase-field model; The phase-field model includes variables, input parameters, free energy functionals, and governing equations; the governing equations include the Cahn-Hilliard equation controlled by the concentration field, the Allen-Cahn equation controlled by the phase field, and the displacement finite element equation controlled by the displacement field. Step 3: Solve the governing equations based on the finite element output file; Based on different strain rates, the convergent solution of the variables is obtained through the phase field model, and the result file is obtained. The sample information includes the matrix size and crack size; the crack size is the average size of pitting corrosion obtained from the SSRT test. The boundary conditions include fixed displacement boundary constraints, specified displacement boundary constraints, and solid-liquid interfaces; the solid-liquid interfaces are located at the crack openings. The finite element output file includes the total number of nodes, the total number of elements, the number of degrees of freedom, the element type, the number of Gaussian points, the node location information at the solid-liquid interface, the number of constrained nodes, and the degree of freedom information at the constraint points. The variables of the phase field model include: strain energy, stress, concentration and order parameter ; The input parameters of the phase-field model include sample material parameters and time integration parameters; the sample material parameters include free energy density curvature, diffusion coefficient, metal atom concentration, saturation concentration of metal ions, elastic modulus of the solid phase, virtual elastic modulus of the liquid phase, Poisson's ratio, interface thickness, and interface dynamic parameters; the time integration parameters include total time step and output step. The specific expression of the free energy functional includes: ； wherein Gtotalrepresents the total free energy; Gchemrepresents the chemical free energy, and specific expressions for the chemical free energy density include: ; wherein, represents the local chemical energy density of a solid metal; represents the local chemical energy density of a liquid; represents a degenerate function; represents the surface energy, and a specific expression of the surface energy density includes: ; where, represents the gradient of the order parameter; represents the gradient energy coefficient, represents the applied double-well barrier height, both through the interfacial energy and the interfacial thickness of the anodic dissolution model were fitted to obtain; represents the double-well potential, and has: ; Indicates strain energy; Indicates displacement; The crack propagation rate was obtained through differential calculation; the crack tip stress and strain energy values ​​at crack initiation were collected; the changes in crack propagation rate, crack tip stress, and strain energy values ​​under different strain rates were compared and judged. When the stress at the crack tip exceeds the yield strength, the cracking is determined to be mechanically caused. When the stress at the crack tip is less than the yield strength, the crack is determined to be caused by both mechanical and electrochemical factors.

2. The simulation method according to claim 1, characterized in that, It also includes step 4, which visualizes the result files for different total time steps to obtain the variable values ​​at the solid-liquid interface under the corresponding total time step and performs crack analysis.

3. A strain rate-based phase-field stress corrosion cracking simulation system employing the simulation method described in any one of claims 1-2, characterized in that, It includes a data acquisition module, a data processing module, and a result generation module; The data acquisition module is used to collect sample information; The data processing module includes finite element model units, phase field model units, and solution units; The finite element model unit is used to construct a finite element model based on sample information and boundary conditions, and a finite element output file is obtained. The phase-field model unit is used to construct the phase-field model; the phase-field model includes variables, input parameters, free energy functionals, and governing equations; the governing equations include the Cahn-Hilliard equation controlled by the concentration field, the Allen-Cahn equation controlled by the phase field, and the displacement finite element equation controlled by the displacement field. The solving unit is used to solve the governing equations based on the finite element output file; Based on different strain rates, the convergent solution of the variables is obtained through the phase field model, and the result file is obtained. The result generation module is used to send the processing results of the solving unit to external systems.

4. A phase-field stress corrosion cracking simulation device based on strain rate, characterized in that, It includes a processor, a memory, and a bus. The memory stores instructions and data read by the processor. The processor is used to call the instructions and data in the memory to execute the simulation method as described in any one of claims 1-2. The bus connects the functional components for transmitting information.

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