Cyclic plasticity analysis method and device, electronic equipment and readable storage medium

Abstract

The application provides a cyclic plasticity analysis method and device, electronic equipment and readable storage medium, and relates to the technical field of metal structure, which comprises the following steps: reading a previous internal state variable of a previous cyclic plasticity process; predicting a first tunneling shear strain and determining a previous kinematic hardening modulus based on the previous internal state variable through a dislocation trap model; determining a second tunneling shear strain of a current cyclic plasticity process; if it is determined that the tunneling state converges, determining a stress-strain relationship based on the previous kinematic hardening modulus; taking the current internal state variable and the stress-strain relationship as a cyclic plasticity analysis result of the current cyclic plasticity process, and continuing to determine a cyclic plasticity analysis result of a next cyclic plasticity process. The application designs a unique dislocation trap model to analyze the kinematic hardening in the cyclic plasticity process, can characterize the kinematic hardening behavior in the cyclic plasticity process based on micro parameters, and improves the applicability of the cyclic plasticity analysis method.

Description

Technical Field

[0001] This invention relates to the field of metal structure technology, and in particular to a cyclic plasticity analysis method, apparatus, electronic device, and readable storage medium. Background Technology

[0002] Kinematic hardening is widely observed in the cyclic deformation of various metals, and this phenomenon is fundamentally related to changes in internal stress and dislocation structure caused by the cyclic loading process. In polycrystalline materials, kinematic hardening is mainly due to the accumulation of polarized dislocations before grain boundaries, while in single crystals it is explained by the cell wall structure of polarized dislocations. Because kinematic hardening is widely associated with the Bauschinger effect, cyclic hardening / softening, mean stress relaxation, yield surface evolution, non-proportional hardening, and ratcheting effect, it plays a crucial role in the constitutive modeling of cyclic plastic deformation in continuum mechanics. Therefore, an accurate description of the kinematic hardening effect is necessary when performing cyclic plasticity analysis of metals.

[0003] While the commonly used Ohno-Wang and Armstrong-Frederick models have stood the test of time and have relatively high accuracy, these types of cyclic plasticity models are only phenomenological, considering only the apparent plastic strain. They cannot be combined with microscopic deformation, and the microscopic simulation and experimental results cannot be reflected in traditional models, thus limiting their use and cross-scale integration. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a cyclic plasticity analysis method, apparatus, electronic device and readable storage medium, and to design a unique dislocation trap model for analyzing kinematic hardening in the cyclic plasticity process, which can characterize the kinematic hardening behavior in the cyclic plasticity process based on microscopic parameters, thereby improving the applicability of the cyclic plasticity analysis method.

[0005] In a first aspect, embodiments of the present invention provide a method for cyclic plasticity analysis, comprising:

[0006] During the current cyclic plasticity process, the previous internal state variables of the previous cyclic plasticity process are read; wherein, the previous internal state variables include at least the previous total shear strain and the previous pile-up shear strain;

[0007] Using a pre-configured dislocation trap model, the first tunneling shear strain of the current cyclic plasticity process is predicted based on the previous total shear strain and the previous pile-up shear strain; and the previous kinematic hardening modulus of the previous cyclic plasticity process is determined based on the previous pile-up shear strain using the dislocation trap model.

[0008] Determine the current internal state variables of the current cyclic plastic process, and determine the second tunneling shear strain of the current cyclic plastic process based on the current internal state variables;

[0009] If the tunneling state convergence of the current cyclic plastic process is determined based on the first tunneling shear strain and the second tunneling shear strain, then the stress-strain relationship of the current cyclic plastic process is determined based on the previous kinematic hardening modulus.

[0010] The current internal state variables and the stress-strain relationship are used as the cyclic plasticity analysis results of the current cyclic plasticity process, and the cyclic plasticity analysis results of the next cyclic plasticity process are determined based on the current internal state variables of the current cyclic plasticity process until the preset iteration stop condition is met.

[0011] In one implementation, the first tunneling shear strain of the current cyclic plastic process is predicted based on the previous total shear strain and the previous pile-up shear strain using a pre-configured dislocation trap model, including:

[0012] Determine the total shear strain rate corresponding to the previous total shear strain; and determine the absolute pile-up strain tolerance based on the distance of the material point to the nearest grain boundary in the slip direction and a preset critical distance;

[0013] Using the dislocation trap model, based on the total shear strain rate, the absolute pile-up strain tolerance, and the previous pile-up shear strain, the tunneling shear strain rate of the current cyclic plastic process is predicted, and the first tunneling shear strain of the current cyclic plastic process is determined based on the tunneling shear strain rate.

[0014] In one embodiment, the absolute pile-up strain tolerance is determined based on the distance of a material point to the nearest grain boundary in the slip direction and a preset critical distance, including:

[0015] The absolute pile-up strain tolerance is determined by multiplying the reciprocal of the sum of the distance of a material point from the nearest grain boundary in the slip direction and the preset critical distance with a preset constant.

[0016] In one implementation, the tunneling shear strain rate of the current cyclic plastic process is predicted using the dislocation trap model, based on the total shear strain rate, the absolute pile-up strain tolerance, and the previous pile-up shear strain, including:

[0017] The tunneling shear strain rate of the current cyclic plastic process is predicted using the following formula:

[0018]

[0019]

[0020] in, For tunneling shear strain rate, s + s - For absolute pile-up strain tolerance, γ imp This represents the shear strain of the previous plug. Let H be the total shear strain rate, and H be the unit step function.

[0021] In one implementation, determining the previous kinematic hardening modulus of the previous cyclic plastic process based on the previous pile-up shear strain using the dislocation trap model includes:

[0022] The previous kinematic hardening modulus of the previous cyclic plastic process is determined based on the odd symmetric function of the previous plug shear strain.

[0023] In one implementation, determining the current internal state variables of the current cyclic plastic process includes:

[0024] Determine the total shear strain increment of the current cyclic plastic process, and take the sum of the total shear strain increment and the previous total shear strain as the current total shear strain of the current cyclic plastic process;

[0025] In addition, the pile-up dislocation density of the current cyclic plastic process is obtained, and the product of the pile-up dislocation density, the Borgs vector length of the dislocation motion, and the length of the mean free path of the dislocation motion is used as the current pile-up shear strain of the current cyclic plastic process.

[0026] The current total shear strain and the current pile-up shear strain are used as the current internal state variables of the current cyclic plastic process.

[0027] In one implementation, determining the second tunneling shear strain of the current cyclic plastic process based on the current internal state variables includes:

[0028] The difference between the current total shear strain and the current pile-up shear strain is taken as the second tunneling shear strain of the current cyclic plastic process.

[0029] Secondly, embodiments of the present invention also provide a cyclic plasticity analysis apparatus, comprising:

[0030] The previous variable reading module is used to read the previous internal state variable of the previous plastic process in the current plastic process; wherein, the previous internal state variable includes at least the previous total shear strain and the previous pile-up shear strain.

[0031] The first strain determination module is used to predict the first tunneling shear strain of the current cyclic plasticity process based on the previous total shear strain and the previous pile-up shear strain using a pre-configured dislocation trap model; and to determine the previous kinematic hardening modulus of the previous cyclic plasticity process based on the previous pile-up shear strain using the dislocation trap model.

[0032] The second strain determination module is used to determine the current internal state variables of the current cyclic plastic process, and to determine the second tunneling shear strain of the current cyclic plastic process based on the current internal state variables.

[0033] The stress-strain relationship determination module is used to determine the stress-strain relationship of the current cyclic plastic process based on the previous kinematic hardening modulus if the tunneling state of the current cyclic plastic process is determined to converge based on the first tunneling shear strain and the second tunneling shear strain.

[0034] The plasticity analysis module is used to take the current internal state variables and the stress-strain relationship as the cyclic plasticity analysis result of the current cyclic plasticity process, and continue to determine the cyclic plasticity analysis result of the next cyclic plasticity process based on the current internal state variables of the current cyclic plasticity process, until the preset iteration stop condition is met.

[0035] Thirdly, embodiments of the present invention also provide an electronic device, including a processor and a memory, the memory storing computer-executable instructions executable by the processor, the processor executing the computer-executable instructions to implement the method described in any of the first aspects.

[0036] Fourthly, embodiments of the present invention also provide a computer-readable storage medium storing computer-executable instructions, which, when invoked and executed by a processor, cause the processor to implement the method described in any of the first aspects.

[0037] This invention provides a method, apparatus, electronic device, and readable storage medium for cyclic plasticity analysis. During the current cyclic plasticity process, it reads the previous internal state variables (including at least the previous total shear strain and the previous pile-up shear strain) from the previous cyclic plasticity process. Then, using a pre-configured dislocation trap model, it predicts the first tunneling shear strain of the current cyclic plasticity process based on the previous total shear strain and the previous pile-up shear strain. Furthermore, using the dislocation trap model, it determines the previous kinematic hardening modulus of the previous cyclic plasticity process based on the previous pile-up shear strain, further determining the current state of the current cyclic plasticity process. The internal state variables are used to determine the second tunneling shear strain of the current cyclic plasticity process. If the tunneling state of the current cyclic plasticity process converges based on the first and second tunneling shear strains, the stress-strain relationship of the current cyclic plasticity process is determined based on the previous kinematic hardening modulus. Finally, the current internal state variables and stress-strain relationship are used as the cyclic plasticity analysis results of the current cyclic plasticity process. The cyclic plasticity analysis results of the next cyclic plasticity process are then determined based on the current internal state variables of the current cyclic plasticity process until the preset iteration stopping condition is met. The above method designs a unique dislocation trap model to analyze kinematic hardening during cyclic plasticity. The dislocation trap model predicts the first tunneling shear strain in the current cyclic plasticity process and determines the previous kinematic hardening modulus in the previous cyclic plasticity process. The first tunneling shear strain is compared with the second tunneling shear strain determined based on the current internal state variables. If the comparison result indicates convergence of the tunneling state, the stress-strain relationship can be determined based on the previous kinematic hardening modulus. The current internal state variables and stress-strain relationship are then used as the cyclic plasticity analysis result for the current cyclic plasticity process. This embodiment of the invention, through the above dislocation trap model, can characterize the kinematic hardening behavior during cyclic plasticity based on microscopic parameters, thus improving the applicability of the cyclic plasticity analysis method.

[0038] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention are realized and obtained in accordance with the structures particularly pointed out in the description, claims and drawings.

[0039] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0040] 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.

[0041] Figure 1 A schematic flowchart of a cyclic plasticity analysis method provided in an embodiment of the present invention;

[0042] Figure 2 A schematic diagram of a dislocation trap provided in an embodiment of the present invention;

[0043] Figure 3 A schematic diagram of dislocation tunneling provided in an embodiment of the present invention;

[0044] Figure 4 A schematic diagram of a curve provided for an embodiment of the present invention;

[0045] Figure 5 A schematic flowchart of another cyclic plasticity analysis method provided in an embodiment of the present invention;

[0046] Figure 6 This is a schematic diagram of the structure of a cyclic plasticity analysis device provided in an embodiment of the present invention;

[0047] Figure 7 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. 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.

[0049] Currently, cyclic plasticity analysis of metals involving kinematic hardening is mainly conducted using the Ohno-Wang model and the Armstrong-Frederick model. In the Ohno-Wang model, for uniaxial loading of isotropic materials, the kinematic hardening variable is calculated by introducing the following equation:

[0050]

[0051] In the formula Let be the total plastic strain, h and m be material constants, and r be the critical value for the magnitude of kinematic hardening. In the Armstrong-Frederick model, the kinematic hardening effect under uniaxial loading is simplified as:

[0052] in, The material parameter is greater than 0.

[0053] Existing cyclic plasticity models are all phenomenological, only considering the apparent plastic strain, and cannot be combined with microscopic deformation. Microscopic simulation and experimental results cannot be reflected in traditional models, and cross-scale integration is not possible. For example, the grain boundary effect of kinematic hardening cannot be accurately considered, which limits their use.

[0054] Based on this, the present invention provides a cyclic plasticity analysis method, apparatus, electronic device, and readable storage medium. A unique dislocation trap model is designed to analyze kinematic hardening during the cyclic plasticity process. It can characterize the kinematic hardening behavior during the cyclic plasticity process based on microscopic parameters, thereby improving the applicability of the cyclic plasticity analysis method.

[0055] To facilitate understanding of this embodiment, a cyclic plasticity analysis method disclosed in this invention will first be described in detail, see [link to relevant documentation]. Figure 1 The diagram shows a flow chart of a cyclic plasticity analysis method, which mainly includes the following steps S102 to S110:

[0056] Step S102: In the current cyclic plasticity process, read the previous internal state variables of the previous cyclic plasticity process. These previous internal state variables include the previous total shear strain, the previous pile-up shear strain, the previous split shear stress, and the previous tunneling state of all octahedral slip systems. This previous tunneling state characterizes the tunneling shear strain of the previous cyclic plasticity process. Additionally, the previous stress of the previous cyclic plasticity process can also be read.

[0057] In one implementation, if the current cyclic plasticity process is the first iteration, the pre-configured initial stress and initial internal state variables can be read directly. The initial internal state variables include the initial total shear strain and initial pile-up shear strain, the initial split shear stress, and the initial tunneling state of all octahedral slip systems. In another implementation, if the current cyclic plasticity process is not the first cycle, the previous stress and previous internal state variables of the previous cyclic plasticity process (i.e., at the end of the previous iteration step) can be read.

[0058] Step S104: Using a pre-configured dislocation well model, predict the first tunneling shear strain of the current cyclic plasticity process based on the previous total shear strain and the previous pile-up shear strain; and determine the previous kinematic hardening modulus of the previous cyclic plasticity process based on the previous pile-up shear strain using the dislocation well model. In one embodiment, the dislocation well model describes the relationship between pile-up shear strain and tunneling shear strain, and the first tunneling shear strain of the current cyclic plasticity process can be predicted based on the described relationship between pile-up shear strain and tunneling shear strain, combined with the previous total shear strain and the previous pile-up shear strain. In another embodiment, the dislocation well model also describes an expression of kinematic hardening caused by pile-up dislocations, and the previous kinematic hardening modulus of the previous cyclic plasticity process can be determined based on the described expression of kinematic hardening caused by pile-up dislocations, combined with the previous pile-up shear strain.

[0059] Step S106: Determine the current internal state variables of the current cyclic plasticity process, and determine the second tunneling shear strain of the current cyclic plasticity process based on the current internal state variables. In one embodiment, an existing algorithm can be used to determine the total shear strain increment of the current cyclic plasticity process, so as to obtain the current total shear strain of the current cyclic plasticity process based on the total shear strain increment. At the same time, the current pile-up shear strain of the current cyclic plasticity process can be obtained according to the pile-up dislocation density, the Boges vector length of dislocation motion, and the length of the mean free path of dislocation motion. Then, the difference between the current total shear strain and the current pile-up shear strain in the current internal state variables is determined as the second tunneling shear strain of the current cyclic plasticity process.

[0060] Step S108: If the tunneling state of the current cyclic plastic process converges based on the first tunneling shear strain and the second tunneling shear strain, then the stress-strain relationship of the current cyclic plastic process is determined based on the previous kinematic hardening modulus. In one embodiment, if the loss value between the first tunneling shear strain and the second tunneling shear strain is less than a preset threshold, the tunneling state of the current cyclic plastic process can be considered to have converged. At this time, the Jacobian matrix of the finite element analysis can be calculated based on the previous kinematic hardening modulus, and then the stress-strain relationship of the current cyclic plastic process can be determined using the Jacobian matrix of the finite element analysis.

[0061] Step S110: The current internal state variables and stress-strain relationship are used as the cyclic plasticity analysis results of the current cyclic plasticity process. The cyclic plasticity analysis results of the next cyclic plasticity process are then determined based on the current internal state variables of the current cyclic plasticity process, until a preset iteration stop condition is met. The preset iteration stop condition may include a preset number of iterations; that is, if the number of iterations in the current cyclic plasticity process reaches the preset number of iterations, the iteration stop condition is considered met.

[0062] The cyclic plasticity analysis method provided in this invention employs a unique dislocation trap model to analyze kinematic hardening during the cyclic plasticity process. The dislocation trap model predicts the first tunneling shear strain in the current cyclic plasticity process and determines the previous kinematic hardening modulus in the previous cyclic plasticity process. The first tunneling shear strain is compared with the second tunneling shear strain determined based on the current internal state variables. If the comparison result indicates convergence of the tunneling state, the stress-strain relationship can be determined based on the previous kinematic hardening modulus. The current internal state variables and stress-strain relationship are then used as the cyclic plasticity analysis result for the current cyclic plasticity process. This invention, through the aforementioned dislocation trap model, can characterize the kinematic hardening behavior during the cyclic plasticity process based on microscopic parameters, thus improving the applicability of the cyclic plasticity analysis method.

[0063] Based on the quantum mechanical potential well concept, this invention presents a unique dislocation well model designed to analyze kinematic hardening during cyclic plasticity, while effectively incorporating grain boundary effects into the model. To facilitate understanding of the dislocation well model, this invention provides a method for constructing the model, specifically:

[0064] Assume the dislocation source O (or simply dislocation source O) is located within a "dislocation trap" barrier, specifically a microscopic barrier on the dislocation slip surface, such as a grain boundary. See also... Figure 2 The diagram shows a dislocation trap, with the two sides of the trap represented by the symbols [↖,↗] and [↙,↘], respectively. The normal vector and slip vector of the corresponding slip surface are respectively... and Since the shear stresses on both sides of the slip surface are equal, it is clear that each well side is symmetrical about the dislocation source O, i.e., [↖,↘] are the same, and [↙,↗] are the same. The "height" of the dislocation well represents its maximum capacity to accommodate pile-up dislocations, which is also the strength of the dislocation barrier. At the same time, drawing on the concept of potential well, it is believed that before the dislocation "overflows" (exceeding the maximum capacity of the pile-up dislocation in the dislocation well), there is a tunneling effect that allows the dislocation to escape through the dislocation well.

[0065] According to dislocation dynamics theory, under the action of shear stress τ, a pair of dislocations with opposite signs will originate from dislocation source O and move towards opposite well sides [↙,↗]. Since the well sides [↙,↗] simultaneously cause pile-up of these dislocations, the number of dislocations piled up on the well side [↗] is... The number of dislocations equal to the number of pile-up dislocations on the well side. Right now Similarly, the number of tunneling dislocations on the well side ↗” and the well side ↙ is also equal, that is If the shear stress τ decreases, the dislocations on the well side at the "↙ and ↗" positions will return to their dislocation sources and decrease in pairs, instead of moving to the opposite well side. Therefore, by the same logic, and Thus far, by distinguishing the positions of dislocations in the upper and lower halves of the model and their states as either pile-up dislocations or tunneling dislocations through the notation on the well side, the well-side symbols "↙" and "↗" are defined as positive well sides, and pile-up dislocations and tunneling dislocations are considered positive. This is the negative well side; therefore, due to the point symmetry of the model, half of the model is sufficient for subsequent analysis. The number of pile-up dislocations z... imp Number of tunneling dislocations z tun The number of dislocations, z, and the total number of dislocations can be calculated using the following formulas:

[0066]

[0067]

[0068]

[0069] See Figure 3 The diagram illustrates a dislocation tunneling process. Under shear stress τ, a pair of opposite dislocations are initially generated at the center, then temporarily blocked by interstitial atoms, and finally pass through the barrier (dislocation tunneling).

[0070] Considering only the velocity of dislocations and neglecting their signs, the pile-up dislocation density ρ imp tunneling dislocation density ρ tun And the total dislocation density ρ can be written as:

[0071]

[0072]

[0073]

[0074] In the formula z imp and z tun The number of pile-up dislocations and tunneling dislocations represents half the area of ​​the selected representative region, where w and g represent the width and length of the region, respectively. Assuming that pile-up dislocations and tunneling dislocations contribute equally to the shear strain, the pile-up shear strain γ... imp Tunneling shear strain γ tun The total shear strain γ can be written as:

[0075]

[0076]

[0077]

[0078] In the formula, b represents the length of the Boges vector of the dislocation, and g represents the length of the mean free path of the dislocation motion.

[0079] Based on experimental findings, dislocations are often hindered at grain boundaries. Therefore, the dislocation density is not constant throughout the grain but increases with decreasing distance from the grain boundary. Here, we assume that the hindering effect on a dislocation is only related to the nearest grain boundary along the slip direction on the slip plane. We consider the pile-up shear strain and tunneling shear strain of dislocations while neglecting their spatial distribution, thus obtaining a description of a positive well. The expression for the lateral tunneling shear strain rate with respect to the plug shear strain is as follows:

[0080]

[0081]

[0082] and These represent the tunneling shear strain rate and the total shear strain rate, respectively; γ imp represents the pile-up shear strain, l represents the distance of a material point to the nearest grain boundary in the slip direction; s + With s - The absolute plugging strain tolerance depends on l on both the positive and negative trap sides; the positive tunneling exponent n + With n - This represents the evolution trend of pile-up and tunneling shear strain on the corresponding trap side; H is a unit step function, that is, H(x) = 1 when x ≥ 0, and H(x) = 0 when x < 0. It is easy to see from the above equation that H(x) = 1 if and only if γ imp and The presence of tunneling shear strain when the signs are the same implies that the dislocation is willing to react with its emission source at the dislocation well boundary, rather than returning to the dislocation source and annihilating. See also Figure 4 The diagram shown is a schematic representation of a curve. Figure 4 To calculate the obtained s + With n + The influence of plug-in shear strain and tunneling shear strain shows that the plug-in shear strain tolerance is only related to s. + Related, n + It only affects the evolution trend of pile-up shear strain and tunneling shear strain. When n + =0, the pile-up shear strain first continues to increase until about s + Saturation occurs, followed by an increase in tunneling shear strain due to dislocation overflow from the dislocation trap; and when n + >0, throughout the loading stage, the tunneling shear strain continuously evolves and reaches its maximum value as the pile-up shear strain gradually saturates.

[0083] By expressing the absolute pile-up strain tolerance function s(l) as a function of grain boundary distance, the influence of grain boundaries on kinematic hardening under cyclic loading can be successfully incorporated into the model.

[0084] In the formula, l represents the distance to the nearest grain boundary, l0 is the critical distance to avoid an infinite value at the grain boundary, and Y is a constant.

[0085] Based on this, the kinematic hardening caused by pile-up dislocations can be expressed as: χ=ψ(γ imp ); where χ is the ratio of γ to γ imp Motion hardening variables with the same sign, ψ represents the relationship with respect to γ imp The odd-symmetric function can be derived through a simple linear relationship: χ = c·γ imp In the formula, c is the linear hardening modulus.

[0086] The equilibrium relationship on the slip surface is: |τ'-|=k0; where τ' represents the shear stress on the slip surface, which can be obtained through Schmidt's law, and k0 is the initial yield resistance on the slip surface.

[0087] The above dislocation trap model can be imported and calculated using the UMAT module in ABAQUS software.

[0088] Based on the dislocation trap model provided in the above embodiments, this invention provides a specific implementation of a cyclic plasticity analysis method. This method is applied to finite element software. (See [link]). Figure 5 The diagram shows another flow chart for cyclic plasticity analysis, which mainly includes the following steps S502 to S514:

[0089] In step S502, the relevant calculation program for the dislocation trap model was called and written through the finite element software.

[0090] Step S504: Read the previous stress and the previous internal state variables at the end of the previous iteration step. The previous internal state variables include the previous total shear strain, the previous pile shear strain, the previous split shear stress, and the previous tunneling state of all octahedral slip systems.

[0091] Step S506: Based on the relationship between plug shear strain and tunneling shear strain, predict the first tunneling shear strain of the current cyclic plastic process, and determine the previous kinematic hardening modulus of each slip system.

[0092] For ease of understanding, this embodiment of the invention provides an implementation method for predicting the first tunneling shear strain of the current cyclic plastic process based on the previous total shear strain and the previous pile-up shear strain using a pre-configured dislocation trap model, as shown in steps 1 to 2 below:

[0093] Step 1: Determine the total shear strain rate corresponding to the previous total shear strain; and determine the absolute pile-up strain tolerance based on the distance of the material point to the nearest grain boundary in the slip direction and a preset critical distance. In practice, the absolute pile-up strain tolerance can be determined by multiplying the reciprocal of the sum of the distance of the material point to the nearest grain boundary in the slip direction and the preset critical distance with a preset constant. Specifically, the absolute pile-up strain tolerance can be determined according to the following steps:

[0094] In the formula, l represents the distance to the nearest grain boundary, l0 is the critical distance to avoid an infinite value at the grain boundary (that is, the above-mentioned preset critical distance), and Y is a constant (that is, the above-mentioned preset constant).

[0095] Step 2: Using the dislocation trap model, based on the total shear strain rate, absolute pile-up strain tolerance, and previous pile-up shear strain, predict the tunneling shear strain rate of the current cyclic plastic process, and determine the first tunneling shear strain of the current cyclic plastic process based on the tunneling shear strain rate. For specific implementation, please refer to (1) to (2) below:

[0096] (1) If the total shear strain rate and the previous pile shear strain are both positive, then determine the first absolute value of the ratio of the previous pile shear strain to the absolute pile strain tolerance on the positive well side, and determine the first index of the first absolute value based on the evolution trend of the pile and tunnel shear strain on the positive well side; determine the tunnel shear strain rate of the current cyclic plastic process based on the total shear strain rate, the first absolute value and the first index.

[0097] (2) If both the total shear strain rate and the previous pile shear strain are negative, then determine the second absolute value of the ratio of the previous pile shear strain to the absolute pile strain tolerance on the negative well side, and determine the second index of the second absolute value based on the evolution trend of the pile and tunnel shear strain on the negative well side; determine the tunnel shear strain rate of the current cyclic plastic process based on the total shear strain rate, the second absolute value and the second index.

[0098] To facilitate understanding of (1) to (2) above, the tunneling shear strain rate of the current cyclic plastic process can be determined according to the following formula:

[0099]

[0100]

[0101] and These represent the tunneling shear strain rate and the total shear strain rate, respectively; γ imp represents the pile-up shear strain, l represents the distance of a material point to the nearest grain boundary in the slip direction; s + With s -The absolute plugging strain tolerance depends on l on both the positive and negative trap sides; the positive tunneling exponent n + With n - It represents the evolution trend of the pile-up and tunneling shear strain on the corresponding trap side; H is the unit step function, that is, H(x) = 1 when x ≥ 0, and H(x) = 0 when x < 0.

[0102] To facilitate understanding, this embodiment of the invention also provides an implementation method for determining the previous kinematic hardening modulus of the previous cycle of plasticity based on the previous pile-up shear strain using a dislocation trap model. The previous kinematic hardening modulus of the previous cycle of plasticity can be determined according to the odd-symmetric function of the previous pile-up shear strain. Specifically, the previous kinematic hardening modulus can be determined according to the following formula:

[0103] χ=ψ(γ imp ) or χ=c·γ imp Where χ is the ratio of γ to γ imp Motion hardening variables with the same sign, ψ represents the relationship with respect to γ imp It is an odd symmetric function, and c is the linear hardening modulus.

[0104] Step S508: Determine the total shear strain increment and the current internal state variables of the current cyclic plastic process. Specifically, see steps a to c below:

[0105] Step a: Determine the total shear strain increment of the current cyclic plastic process, and use the sum of the total shear strain increment and the previous total shear strain as the current total shear strain of the current cyclic plastic process.

[0106] In one implementation, the total shear strain increment of the current cyclic plasticity process can be determined using existing algorithms, such as those described in Rate Independent Crystal Plasticity.

[0107] For example, the total shear strain increment of all 12 slip systems can be obtained using the following formula:

[0108]

[0109] Where L is the fourth-order anisotropic stiffness tensor of the single crystal, u α For α th Sliding system The symmetrical part, Δε is the total strain increment, δ αβ Let y be the Kronecker notation, and y be the kinematic hardening modulus with respect to the total shear strain increment Δγ, which depends on the contribution of the tunneling factor.

[0110] After determining the total shear strain increment, the sum of the total shear strain increment and the previous total shear strain can be used as the current total shear strain for the current cyclic plastic process.

[0111] Step b: Obtain the pile-up dislocation density of the current cyclic plastic process. The product of the pile-up dislocation density, the Borgs vector length of the dislocation motion, and the mean free path length of the dislocation motion is used as the current pile-up shear strain of the current cyclic plastic process. In one embodiment, the current pile-up shear strain of the current cyclic plastic process can be determined according to the following formula:

[0112] In the formula, b represents the length of the Boges vector of the dislocation, and g represents the length of the mean free path of the dislocation motion.

[0113] Step c: The current total shear strain and the current pile-up shear strain are used as the current internal state variables of the current cyclic plastic process.

[0114] Step S510: Based on the current stress and current internal state variables, compare them with the first tunneling shear strain to determine whether the tunneling state has converged. If yes, proceed to step S512; if no, proceed to step S506.

[0115] In one implementation, the difference between the current total shear strain and the current pile-up shear strain can be used as the second tunneling shear strain in the current cyclic plasticity process. Then, the first tunneling shear strain and the second tunneling shear strain are compared. If the loss value of both is less than a preset threshold, the tunneling state can be determined to have converged.

[0116] Step S512: Save the current stress and current internal state variables of the current cyclic plastic process, and calculate the Jacobian matrix for finite element analysis. In one embodiment, the Jacobian matrix can be determined based on the previous kinematic hardening modulus.

[0117] Step S514: Return the solved Jacobian matrix to the finite element software.

[0118] In summary, the cyclic plasticity analysis method provided by the embodiments of the present invention can characterize the kinematic hardening behavior in the cyclic plasticity process based on microscopic parameters, and can also incorporate the influence of grain boundary effects on kinematic hardening into the model.

[0119] Regarding the cyclic plasticity analysis method provided in the foregoing embodiments, this invention provides a cyclic plasticity analysis apparatus, see [link to relevant documentation]. Figure 6 The diagram shows a structural schematic of a cyclic plasticity analysis device, which mainly includes the following parts:

[0120] The previous variable reading module 602 is used to read the previous internal state variable of the previous plastic process in the current plastic process; wherein, the previous internal state variable includes at least the previous total shear strain and the previous pile-up shear strain.

[0121] The first strain determination module 604 is used to predict the first tunneling shear strain of the current cyclic plasticity process based on the previous total shear strain and the previous pile-up shear strain using a pre-configured dislocation trap model; and to determine the previous kinematic hardening modulus of the previous cyclic plasticity process based on the previous pile-up shear strain using the dislocation trap model.

[0122] The second strain determination module 606 is used to determine the current internal state variables of the current cyclic plastic process, and to determine the second tunneling shear strain of the current cyclic plastic process based on the current internal state variables.

[0123] The stress-strain relationship determination module 608 is used to determine the stress-strain relationship of the current cyclic plastic process based on the previous kinematic hardening modulus if the tunneling state of the current cyclic plastic process converges based on the first tunneling shear strain and the second tunneling shear strain.

[0124] The plasticity analysis module 610 is used to take the current internal state variables and stress-strain relationship as the cyclic plasticity analysis result of the current cyclic plasticity process, and continue to determine the cyclic plasticity analysis result of the next cyclic plasticity process based on the current internal state variables of the current cyclic plasticity process, until the preset iteration stop condition is met.

[0125] The cyclic plasticity analysis apparatus provided in this invention features a unique dislocation trap model designed to analyze kinematic hardening during the cyclic plasticity process. The dislocation trap model predicts the first tunneling shear strain in the current cyclic plasticity process and determines the previous kinematic hardening modulus in the previous cyclic plasticity process. The first tunneling shear strain is compared with the second tunneling shear strain determined based on the current internal state variables. If the comparison result indicates convergence of the tunneling state, the stress-strain relationship can be determined based on the previous kinematic hardening modulus. The current internal state variables and stress-strain relationship are then used as the cyclic plasticity analysis result for the current cyclic plasticity process. This invention, through the aforementioned dislocation trap model, can characterize the kinematic hardening behavior during the cyclic plasticity process based on microscopic parameters, thus improving the applicability of the cyclic plasticity analysis method.

[0126] In one embodiment, the first strain determination module 604 is further configured to:

[0127] Determine the total shear strain rate corresponding to the previous total shear strain; and determine the absolute pile-up strain tolerance based on the distance of the material point to the nearest grain boundary in the slip direction and the preset critical distance;

[0128] Using the dislocation trap model, based on the total shear strain rate, absolute pile-up strain tolerance, and previous pile-up shear strain, the tunneling shear strain rate of the current cyclic plastic process is predicted, and the first tunneling shear strain of the current cyclic plastic process is determined based on the tunneling shear strain rate.

[0129] In one embodiment, the first strain determination module 604 is further configured to:

[0130] The absolute pile-up strain tolerance is determined by multiplying the reciprocal of the sum of the distance of a material point from the nearest grain boundary in the slip direction and the preset critical distance with a preset constant.

[0131] In one embodiment, the first strain determining module 604 is further configured to:

[0132] The tunneling shear strain rate of the current cyclic plastic process is predicted using the following formula:

[0133]

[0134]

[0135] in, For tunneling shear strain rate, s + s - For absolute pile-up strain tolerance, γ imp This represents the shear strain of the previous plug. Let H be the total shear strain rate, and H be the unit step function.

[0136] In one embodiment, the first strain determination module 604 is further configured to:

[0137] Based on the odd-symmetric function of the previous plug shear strain, determine the previous kinematic hardening modulus of the previous cyclic plastic process.

[0138] In one implementation, determining the current internal state variables of the current cyclic plastic process includes:

[0139] Determine the total shear strain increment of the current cyclic plastic process, and take the sum of the total shear strain increment and the previous total shear strain as the current total shear strain of the current cyclic plastic process;

[0140] In addition, the pile-up dislocation density of the current cyclic plastic process is obtained, and the product of the pile-up dislocation density, the Boges vector length of the dislocation motion, and the length of the mean free path of the dislocation motion is used as the current pile-up shear strain of the current cyclic plastic process.

[0141] The current total shear strain and the current pile-up shear strain are used as the current internal state variables of the current cyclic plastic process.

[0142] In one embodiment, the second strain determination module 606 is further configured to:

[0143] The difference between the current total shear strain and the current pile-up shear strain is taken as the second tunneling shear strain in the current cyclic plastic process.

[0144] The device provided in this embodiment of the invention has the same implementation principle and technical effect as the aforementioned method embodiment. For the sake of brevity, any parts not mentioned in the device embodiment can be referred to the corresponding content in the aforementioned method embodiment.

[0145] This invention provides an electronic device, specifically, the electronic device includes a processor and a storage device; the storage device stores a computer program, and the computer program, when run by the processor, executes the method described in any of the above embodiments.

[0146] Figure 7 The present invention provides a schematic diagram of the structure of an electronic device 100, which includes a processor 70, a memory 71, a bus 72 and a communication interface 73. The processor 70, the communication interface 73 and the memory 71 are connected through the bus 72. The processor 70 is used to execute executable modules, such as computer programs, stored in the memory 71.

[0147] The memory 71 may include high-speed random access memory (RAM) or non-volatile memory, such as at least one disk storage device. Communication between this system network element and at least one other network element is achieved through at least one communication interface 73 (which can be wired or wireless), such as the Internet, wide area network, local area network, metropolitan area network, etc.

[0148] Bus 72 can be an ISA bus, PCI bus, or EISA bus, etc. The bus can be divided into address bus, data bus, control bus, etc. For ease of representation, Figure 7 The symbol is represented by a single double-headed arrow, but this does not mean that there is only one bus or one type of bus.

[0149] The memory 71 is used to store programs. After receiving an execution instruction, the processor 70 executes the programs. The method executed by the device for defining the flow process disclosed in any of the foregoing embodiments of the present invention can be applied to the processor 70 or implemented by the processor 70.

[0150] The processor 70 may be an integrated circuit chip with signal processing capabilities. In implementation, each step of the above method can be completed by the integrated logic circuitry in the hardware of the processor 70 or by instructions in software form. The processor 70 may be a general-purpose processor, including a Central Processing Unit (CPU), a Network Processor (NP), etc.; it may also be a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field-Programmable Gate Array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this invention. The general-purpose processor may be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this invention can be directly embodied in the execution of a hardware decoding processor, or executed by a combination of hardware and software modules in the decoding processor. The software modules may reside in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. The storage medium is located in memory 71. Processor 70 reads the information in memory 71 and, in conjunction with its hardware, completes the steps of the above method.

[0151] The computer program product of the readable storage medium provided in the embodiments of the present invention includes a computer-readable storage medium storing program code. The instructions included in the program code can be used to execute the methods described in the foregoing method embodiments. For specific implementation, please refer to the foregoing method embodiments, which will not be repeated here.

[0152] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, essentially, or the part that contributes to the prior art, or a portion 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, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0153] 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 it. 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 technical scope 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. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for cyclic plasticity analysis, characterized in that, include: During the current cyclic plasticity process, the previous internal state variables of the previous cyclic plasticity process are read; wherein, the previous internal state variables include at least the previous total shear strain and the previous pile-up shear strain; Using a pre-configured dislocation trap model, the first tunneling shear strain of the current cyclic plasticity process is predicted based on the previous total shear strain and the previous pile-up shear strain; and the previous kinematic hardening modulus of the previous cyclic plasticity process is determined based on the previous pile-up shear strain using the dislocation trap model. Determine the current internal state variables of the current cyclic plastic process, and determine the second tunneling shear strain of the current cyclic plastic process based on the current internal state variables; If the tunneling state convergence of the current cyclic plastic process is determined based on the first tunneling shear strain and the second tunneling shear strain, then the stress-strain relationship of the current cyclic plastic process is determined based on the previous kinematic hardening modulus. The current internal state variables and the stress-strain relationship are used as the cyclic plasticity analysis results of the current cyclic plasticity process, and the cyclic plasticity analysis results of the next cyclic plasticity process are determined based on the current internal state variables of the current cyclic plasticity process until the preset iteration stop condition is met. Using a pre-configured dislocation trap model, based on the previous total shear strain and the previous pile-up shear strain, the first tunneling shear strain of the current cyclic plastic process is predicted, including: Determine the total shear strain rate corresponding to the previous total shear strain; And the absolute pile-up strain tolerance is determined based on the distance of the material point from the nearest grain boundary in the slip direction and a preset critical distance, including: the product of the reciprocal of the sum of the distance of the material point from the nearest grain boundary in the slip direction and the preset critical distance and a preset constant is determined as the absolute pile-up strain tolerance; Using the dislocation trap model, based on the total shear strain rate, the absolute pile-up strain tolerance, and the previous pile-up shear strain, the tunneling shear strain rate of the current cyclic plastic process is predicted, and the first tunneling shear strain of the current cyclic plastic process is determined according to the tunneling shear strain rate, including: predicting the tunneling shear strain rate of the current cyclic plastic process according to the following formula: ； ； in, The tunnel shear strain rate is... This represents the distance of a material point from the nearest grain boundary along the slip direction. For the positive and negative well sides to depend on Absolute plugging strain tolerance, positive tunneling index and This represents the evolution trend of pile-up and tunneling shear strain on the corresponding trap side. This represents the shear strain of the previous plug. The total shear strain rate is... It is a unit step function; Determining the current internal state variables of the current cyclic plastic process includes: Determine the total shear strain increment of the current cyclic plastic process, and take the sum of the total shear strain increment and the previous total shear strain as the current total shear strain of the current cyclic plastic process; In addition, the pile-up dislocation density of the current cyclic plastic process is obtained, and the product of the pile-up dislocation density, the Borgs vector length of the dislocation motion, and the length of the mean free path of the dislocation motion is used as the current pile-up shear strain of the current cyclic plastic process. The current total shear strain and the current pile-up shear strain are used as the current internal state variables of the current cyclic plastic process.

2. The cyclic plasticity analysis method according to claim 1, characterized in that, Using the dislocation trap model, the previous kinematic hardening modulus of the previous cyclic plastic process is determined based on the previous pile-up shear strain, including: Using the dislocation trap model, the previous kinematic hardening modulus of the previous cyclic plastic process is determined based on the odd symmetric function of the previous pile-up shear strain.

3. The cyclic plasticity analysis method according to claim 1, characterized in that, Determining the second tunneling shear strain of the current cyclic plastic process based on the current internal state variables includes: The difference between the current total shear strain and the current pile-up shear strain is taken as the second tunneling shear strain of the current cyclic plastic process.

4. A cyclic plasticity analysis device, characterized in that, The apparatus for implementing the cyclic plasticity analysis method of claim 1 includes: The previous variable reading module is used to read the previous internal state variable of the previous plastic process in the current plastic process; wherein, the previous internal state variable includes at least the previous total shear strain and the previous pile-up shear strain. The first strain determination module is used to predict the first tunneling shear strain of the current cyclic plasticity process based on the previous total shear strain and the previous pile-up shear strain using a pre-configured dislocation trap model; and to determine the previous kinematic hardening modulus of the previous cyclic plasticity process based on the previous pile-up shear strain using the dislocation trap model. The second strain determination module is used to determine the current internal state variables of the current cyclic plastic process, and to determine the second tunneling shear strain of the current cyclic plastic process based on the current internal state variables. The stress-strain relationship determination module is used to determine the stress-strain relationship of the current cyclic plastic process based on the previous kinematic hardening modulus if the tunneling state of the current cyclic plastic process is determined to converge based on the first tunneling shear strain and the second tunneling shear strain. The plasticity analysis module is used to take the current internal state variables and the stress-strain relationship as the cyclic plasticity analysis result of the current cyclic plasticity process, and continue to determine the cyclic plasticity analysis result of the next cyclic plasticity process based on the current internal state variables of the current cyclic plasticity process, until the preset iteration stop condition is met.

5. An electronic device, characterized in that, The method includes a processor and a memory, the memory storing computer-executable instructions executable by the processor, the processor executing the computer-executable instructions to implement the method of any one of claims 1 to 3.

6. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions that, when invoked and executed by a processor, cause the processor to perform the method described in any one of claims 1 to 3.

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