Stress prediction method based on creep-containing first-stage regeneration effect

Abstract

The invention discloses a stress prediction method based on a creep-containing first-stage regeneration effect, and the method comprises the steps: constructing a total stress decomposition model containing the creep-containing first-stage regeneration effect, which comprises an elastic strain module, a plastic strain module and a creep strain module; correcting the plastic strain module based on a preset nonlinear motion hardening model and an isotropic hardening rule; correcting the creep model of the creep strain module through a preset creep correction rule; obtaining a target non-uniform constitutive model based on the elastic strain module, the corrected target plastic strain module and the target creep strain module; target material parameters of a to-be-tested material are obtained through a preset material mechanical property test and substituted into the target non-uniform constitutive model, and strain information of the to-be-tested material under the high-temperature cyclic load is obtained through prediction. Therefore, the strain information under the high-temperature cyclic load can be accurately predicted, so that the creep behavior and the experimental life of the material can be effectively predicted.

Description

Technical Field

[0001] The present application relates to the technical field of material stress analysis, and in particular to a stress prediction method based on the first-stage regeneration effect of creep. Background Art

[0002] With advancements in fourth-generation nuclear technology and improvements in operational efficiency, the operating conditions of nuclear power equipment are becoming increasingly demanding, placing higher demands on material performance. Fluctuations in load and temperature subject materials to cyclic loading, further complicating their stress-strain response. Therefore, understanding the mechanical behavior of materials under cyclic creep loading is crucial for accurately predicting the stress-strain response of high-temperature structures and ensuring the reliability and safety of nuclear power plants.

[0003] Primary creep regeneration (PCR) behavior refers to the degradation of the strain hardening memory of a material when subjected to reverse loading. This degradation causes subsequent forward creep to exhibit high strain rate deformation behavior, similar to the first stage of creep. The recurrence of this phenomenon prolongs the duration of the first stage of creep, amplifies creep deformation, and accelerates material failure.

[0004] Therefore, how to improve the accuracy of the evolution analysis of the regeneration effect of the first stage of creep of materials is an urgent problem to be solved. Summary of the Invention

[0005] In order to solve the above problems, the embodiments of the present application provide a stress prediction method and device based on the first stage regeneration effect of creep, an electronic device, a computer-readable storage medium, and a computer program product.

[0006] In the first aspect, in order to solve the above technical problems, the present application provides a stress prediction method based on the first stage regeneration effect of creep, comprising:

[0007] Constructing a total stress decomposition model for the material including the first stage regeneration effect of creep, wherein the total stress decomposition model includes an elastic strain module, a plastic strain module, and a creep strain module;

[0008] The plastic strain module is modified based on a preset nonlinear kinematic hardening model and an isotropic hardening rule to obtain a target plastic strain module;

[0009] Correcting the creep model of the creep strain module by using a preset creep correction rule to obtain a target creep strain module;

[0010] Obtaining a target non-unified constitutive model based on the elastic strain module, the target plastic strain module, and the target creep strain module;

[0011] Obtain target material parameters of a preset type of material to be tested through a preset material mechanical property test;

[0012] The target material parameters are substituted into the target non-uniform constitutive model, and the strain information of the material to be tested under high temperature cyclic loading is predicted by the target non-uniform constitutive model.

[0013] The beneficial effects are:

[0014] In the technical solution provided in the embodiments of the present application, the total strain decomposition model is divided into modules corresponding to elastic, plastic and creep strain components, and the total strain decomposition model is adaptively modified for the purpose of considering the PCR phenomenon during cyclic creep. The nonlinear kinematic hardening model is used to describe the ratchet effect in cyclic loading for the plastic strain module, and a preset isotropic hardening rule is introduced to capture the cyclic tension-compression asymmetry. The creep strain module uses the creep model to consider the PCR phenomenon during cyclic creep, so that the target non-uniform constitutive model formed after the correction can assume that the complete PCR behavior occurs in each cycle, effectively capturing the asymmetric tension-compression behavior and PCR evolution of the material during the cycle, and providing a reliable description of the stress-strain response during cyclic creep loading. In this way, when applying the target non-uniform constitutive model, by substituting the target material parameters of the material to be tested into the corresponding parameter positions, the strain information under high-temperature cyclic loading can be accurately predicted, thereby effectively predicting the creep behavior and experimental life of the material.

[0015] Furthermore, the total stress decomposition model containing the first stage creep regeneration effect for the material is constructed, and the total stress decomposition model includes an elastic strain module, a plastic strain module and a creep strain module, including:

[0016] Based on Hooke's law, the elastic strain module is constructed;

[0017] The plastic strain module is constructed based on the viscoplastic flow equation;

[0018] The creep strain module is constructed based on the primary-secondary creep model;

[0019] Based on the elastic strain module, the plastic strain module and the creep strain module, a total stress decomposition model including the first stage creep regeneration effect for the material is constructed.

[0020] Furthermore, the equation of the total stress decomposition model is:

[0021]

[0022] Among them, ε is the total strain decomposition model, and e, p, and c represent the components of elastic, plastic, and creep strains, respectively.

[0023] Furthermore, the equation of the plastic strain module is:

[0024]

[0025] Among them, K and n are viscoplastic material parameters representing the viscosity of the material, Sa is the deviation between stress and back stress, σ y is the initial yield stress, and R is the isotropic hardening of the accumulated plastic strain.

[0026] Furthermore, the plastic strain module is modified based on the preset nonlinear kinematic hardening model and isotropic hardening rule to obtain a target plastic strain module, including:

[0027] Correcting the back stress component of the plastic strain module by a nonlinear motion hardening model to obtain a back stress component correction term, wherein the nonlinear motion hardening model includes a back stress component superposition equation and a back stress component evolution equation;

[0028] Correcting the isotropic hardening of the plastic strain module using a preset isotropic hardening rule to obtain an isotropic hardening correction term;

[0029] The isotropic hardening correction term and the isotropic hardening correction term are applied to the plastic strain module to obtain a target plastic strain module.

[0030] Furthermore, the back stress component superposition equation of the nonlinear kinematic hardening model is:

[0031]

[0032] The back stress component evolution equation is:

[0033]

[0034] Where M is the total number of back stresses, ζ i , μ is the dynamic hardening material parameter, r i is the temperature material parameter related to back stress and temperature, and H() is the Heaviside step function.

[0035] Furthermore, the equation of the isotropic hardening rule is:

[0036] R=R c (p)-J m (σ)

[0037] Among them, J m (σ) is the first stress invariant,

[0038] J m(σ)=η|trσ| l sgn(trσ);

[0039] R C (p) = Q[1-exp(-bp)], where Q and b are isotropic hardening parameters, η and l are asymmetric material parameters related to cyclic tension-compression asymmetry, trσ is the stress tensor trajectory, and sgn(x) represents the sign function.

[0040] Furthermore, the creep model of the creep strain module is corrected by using a preset creep correction rule to obtain a target creep strain module, including:

[0041] Based on the preset creep correction rule, the equivalent creep strain related to the number of cycles is obtained;

[0042] The creep model of the creep strain module is modified based on the equivalent creep strain to obtain a target creep model for the evolution of the regenerative effect behavior in the first stage of creep, thereby forming a target creep strain module.

[0043] Furthermore, the target creep model is expressed as:

[0044]

[0045] in, is the equivalent creep strain of the ith cycle, λ and β are creep material parameters, ε pr,i is the creep strain increment at the transition point from the primary creep stage to the secondary creep stage within each holding cycle;

[0046]

[0047] Among them, C1, C2, χ1, χ2 are fitting parameters, ∈ ini is the initial equivalent plastic strain, ε rev,i-1 is the reverse plastic strain for each cycle.

[0048] Furthermore, the target material parameters include target elastic parameters, target viscoplastic material parameters, target isotropic hardening parameters, target asymmetric material parameters, target dynamic hardening material parameters and target creep material parameters;

[0049] The method of obtaining target material parameters of a preset type of the material to be tested through a preset material mechanical property test includes:

[0050] Through uniaxial tensile tests, target elastic parameters and target viscoplastic material parameters are obtained;

[0051] Through strain-controlled cyclic tests, the target isotropic hardening parameters and target asymmetric material parameters are obtained by fitting.

[0052] The target dynamic hardening material parameters are obtained by inversion using the experimental data of the uniaxial ratchet test;

[0053] Through stress-controlled creep tests, the target creep material parameters are fitted.

[0054] In a second aspect, the present invention provides a stress prediction device based on the first stage regeneration effect of creep, comprising:

[0055] A construction unit is used to construct a total stress decomposition model containing a first-stage creep regeneration effect for the material, wherein the total stress decomposition model includes an elastic strain module, a plastic strain module, and a creep strain module;

[0056] A plastic strain correction unit, configured to correct the plastic strain module based on a preset nonlinear kinematic hardening model and an isotropic hardening rule to obtain a target plastic strain module;

[0057] A creep strain correction unit, configured to correct the creep model of the creep strain module according to a preset creep correction rule to obtain a target creep strain module;

[0058] a processing unit, configured to obtain a target non-unified constitutive model based on the elastic strain module, the target plastic strain module, and the target creep strain module;

[0059] A test data acquisition unit, used to obtain target material parameters of a preset type of the material to be tested through a preset material mechanical property test;

[0060] A prediction unit is used to substitute the target material parameters into the target non-uniform constitutive model, and predict the strain information of the material to be tested under high temperature cyclic loading through the target non-uniform constitutive model.

[0061] In a third aspect, the present application also provides an electronic device comprising: one or more processors; a storage device for storing one or more programs, wherein when the one or more programs are executed by the one or more processors, the electronic device implements the stress prediction method based on the first stage regeneration effect of creep as described above.

[0062] In a fourth aspect, the present application also provides a computer-readable storage medium having computer-readable instructions stored thereon. When the computer-readable instructions are executed by a computer processor, the computer executes the stress prediction method based on the first-stage regeneration effect of creep as described above.

[0063] In a fifth aspect, the present application further provides a computer program product or computer program, comprising computer instructions stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium and executes the computer instructions, causing the computer device to perform the stress prediction method based on the creep first-stage regeneration effect provided in the various optional embodiments described above.

[0064] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] The accompanying drawings are incorporated into and constitute a part of the specification, illustrating embodiments consistent with the present application and, together with the specification, serving to explain the principles of the present application. It is obvious that the drawings described below are merely some embodiments of the present application, and a person of ordinary skill in the art can derive other drawings based on these drawings without inventive effort. In the drawings:

[0066] Figure 1 This is a flowchart of a stress prediction method based on the first stage regeneration effect of creep, shown in an exemplary embodiment of the present application;

[0067] Figure 2 is a schematic diagram comparing creep strain predicted by a target non-unified constitutive model and test results in an exemplary embodiment of the present application;

[0068] Figure 3 is a schematic diagram comparing the strain-time response under test and the strain-time response predicted by the target non-unified constitutive model in an exemplary embodiment of the present application;

[0069] Figure 4 This is a block diagram of a stress prediction device based on the first stage regeneration effect of creep, shown in an exemplary embodiment of the present application;

[0070] Figure 5 It is a structural diagram of a computer system suitable for implementing the electronic device of the embodiment of the present application. DETAILED DESCRIPTION

[0071] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present application, as detailed in the appended claims.

[0072] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically separate entities. That is, these functional entities may be implemented in software, in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0073] The flowcharts shown in the accompanying drawings are for illustrative purposes only and do not necessarily include all contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps may be decomposed, while others may be combined or partially combined. Therefore, the actual execution order may vary depending on the actual situation.

[0074] In this application, "plurality" refers to two or more. "And / or" describes the relationship between related objects, indicating that three possible relationships exist. For example, "A and / or B" can mean: A exists alone, A and B exist simultaneously, and B exists alone. The character " / " generally indicates that the related objects are in an "or" relationship.

[0075] In the related art, for the analysis of the regenerative effect behavior of the first stage of creep, the viscoplastic constitutive model has been proven to be particularly effective in simulating the time-varying deformation behavior of metal materials under high temperature environments. Based on their treatment of time-varying plastic strain and time-varying creep strain, viscoplastic models can be divided into non-unified constitutive models and unified constitutive models. The unified constitutive model solves plastic deformation and creep deformation at the same time, which can more accurately describe the creep-plastic interaction. However, these models are limited when applied to conditions where creep is the dominant factor, and rarely consider the PCR phenomenon during cyclic creep. The model does not solve the problem of predicting plastic deformation and ratcheting behavior. It can be seen that there is an urgent need for a method to construct a non-unified constitutive model of a material containing the regenerative effect of the first stage of creep, so as to meet the needs of exploring cyclic loading behavior and the influence of PCR on the material during cyclic loading.

[0076] In order to solve the above problems, the embodiments of the present application propose a stress prediction method and device based on the first stage regeneration effect of creep, an electronic device, and a computer-readable storage medium, which mainly involve stress prediction technology based on non-unified constitutive models included in material stress analysis technology. These embodiments will be described in detail below.

[0077] First see Figure 1 , Figure 1This is a flowchart illustrating a stress prediction method based on the creep first-stage regeneration effect, as illustrated by an exemplary embodiment of the present application. The method can be specifically executed by a server, which can be a standalone server or a cloud server that provides basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communications, middleware services, domain name services, security services, content delivery networks (CDNs), and big data and artificial intelligence platforms, without limitation herein.

[0078] like Figure 1 As shown, in an exemplary embodiment, the stress prediction method based on the creep first stage regeneration effect may include steps S101 to S106, which are described in detail as follows:

[0079] Step S101 : constructing a total stress decomposition model for the material including the first stage creep regeneration effect, wherein the total stress decomposition model includes an elastic strain module, a plastic strain module, and a creep strain module.

[0080] Step S102 : Modifying the plastic strain module based on a preset nonlinear kinematic hardening model and an isotropic hardening rule to obtain a target plastic strain module.

[0081] Step S103 : Correcting the creep model of the creep strain module using a preset creep correction rule to obtain a target creep strain module.

[0082] Step S104 : obtaining a target non-uniform constitutive model based on the elastic strain module, the target plastic strain module, and the target creep strain module.

[0083] Step S105 : obtaining target material parameters of a preset type of the material to be tested through a preset material mechanical property test.

[0084] Step S106 , substituting the target material parameters into the target non-uniform constitutive model, and predicting the strain information of the material to be tested under high temperature cyclic loading by using the target non-uniform constitutive model.

[0085] As can be seen from the above, in the method provided in this embodiment, on the one hand, a total stress decomposition model containing the first stage regeneration effect of creep is constructed for the material, and the total stress decomposition model includes an elastic strain module, a plastic strain module and a creep strain module; based on the preset nonlinear motion hardening model and the isotropic hardening rule, the plastic strain module is corrected to obtain a target plastic strain module; through the preset creep correction rule, the creep model of the creep strain module is corrected to obtain a target creep strain module; based on the elastic strain module, the target plastic strain module and the target creep strain module, a target non-uniform constitutive model is obtained. In this way, the target non-uniform constitutive model formed after the correction of this application can assume that the complete PCR behavior occurs in each cycle, effectively capture the asymmetric tensile and compressive behavior of the material during the cycle and the evolution of PCR, and provide a reliable description of the stress-strain response during cyclic creep loading.

[0086] On the other hand, when applying the target non-uniform constitutive model, the target material parameters of the preset type of the material to be tested are obtained through a preset material mechanical property test; the target material parameters are substituted into the target non-uniform constitutive model, and the strain information of the material to be tested under high-temperature cyclic load is predicted through the target non-uniform constitutive model. In this way, by substituting the target material parameters of the material to be tested into the corresponding parameter positions, the present application can accurately predict the strain information under high-temperature cyclic load, including but not limited to stress-strain response, creep accumulation and strain-time evolution law, thereby significantly improving the capture of cyclic stress-strain response of materials containing PCR behavior, and is suitable for durability analysis and optimization design of high-temperature components in the fields of nuclear power, chemical industry, etc., thereby effectively predicting the creep behavior and experimental life of the material.

[0087] In an exemplary embodiment of the present application, the steps of constructing a total stress decomposition model for a material including the first stage creep regeneration effect may specifically include:

[0088] Based on Hooke's law, the elastic strain module is constructed;

[0089] The plastic strain module is constructed based on the viscoplastic flow equation;

[0090] The creep strain module is constructed based on the primary-secondary creep model;

[0091] Based on the elastic strain module, plastic strain module and creep strain module, a total stress decomposition model including the first stage creep regeneration effect of the material is constructed.

[0092] Hooke's law is the basis for the development of elastic mechanics, and is applicable to some materials under specific loading conditions. Therefore, in this embodiment, an elastic strain module is calculated and constructed based on Hooke's law. The viscoplastic flow equation is a mathematical expression that describes the relationship between stress, strain and strain rate of viscoplastic materials when they are subjected to stress, and can well reflect the plastic strain of the material. Therefore, in this embodiment, in addition, creep refers to the plastic deformation behavior of a substance when it is exposed to high temperature for a long time, which is mainly divided into primary creep, secondary creep and stable creep. Primary creep is rapid deformation under actual stress, and secondary creep is gradual deformation under decreasing stress. Therefore, in this embodiment, in order to analyze the stress of the material containing the regeneration effect of the first stage of creep, a creep strain module is constructed based on the primary-secondary creep model.

[0093] In another exemplary embodiment, the equation of the total stress decomposition model is:

[0094]

[0095] Among them, ε is the total strain decomposition model, e, p, and c represent the components of elastic, plastic, and creep strains, respectively. That is, in this embodiment, ε e Characterized as elastic strain module, ε p Characterized as a plastic strain module, ε c Characterized as a creep strain module.

[0096] In another exemplary embodiment, the plastic strain module may be expressed as:

[0097]

[0098] Among them, K and n are viscoplastic material parameters representing the viscosity of the material, Sa is the deviation between stress and back stress, σ y is the initial yield stress, R is the isotropic hardening of the accumulated plastic strain. In addition, the Macaulay bracket <x>Expressed as the differential with respect to time t, the variable x in Macaulay brackets is defined as x = 0 when x < 0 and x = x when x ≥ 0.

[0099] In this way, through the above embodiments, the present application decomposes the total strain model into modules corresponding to elastic, plastic and creep strain components. The plastic strain module and the creep strain module are used for correction in subsequent steps so that the obtained target non-unified constitutive model can assume that the complete PCR behavior occurs in each cycle, effectively capturing the asymmetric tensile and compressive behavior of the material during the cycle and the evolution of PCR, and providing a reliable description of the stress-strain response during cyclic creep loading.

[0100] In an exemplary embodiment provided herein, the specific steps of modifying the plastic strain module based on a preset nonlinear kinematic hardening model and an isotropic hardening rule to obtain a target plastic strain module may include:

[0101] The back stress component of the plastic strain module is corrected by a nonlinear motion hardening model to obtain a back stress component correction term. The nonlinear motion hardening model includes a back stress component superposition equation and a back stress component evolution equation.

[0102] The isotropic hardening of the plastic strain module is corrected by the preset isotropic hardening rule to obtain the isotropic hardening correction term;

[0103] The isotropic hardening correction term and the isotropic hardening correction term are applied to the plastic strain module to obtain the target plastic strain module.

[0104] In another exemplary embodiment, the back stress component superposition equation of the nonlinear kinematic hardening model is:

[0105]

[0106] The evolution of the back stress component is controlled by the dynamic hardening material parameters and the Heaviside step function. The back stress component evolution equation is:

[0107] Where M is the total number of back stresses, ζ i , μ is the dynamic hardening material parameter, r i is the temperature material parameter related to back stress and temperature, and H() is the Heaviside step function.

[0108] In another exemplary embodiment, the isotropic hardening of the plastic strain module is corrected by using a preset isotropic hardening rule. Specifically, a correction term for the first stress invariant is first obtained. Then, the isotropic hardening rule is obtained by combining the classical isotropic hardening term with the correction term for the first stress invariant. The isotropic hardening rule is then implemented to correct the isotropic hardening of the plastic strain module to obtain the isotropic hardening correction term. The implementation equation of the isotropic hardening rule is:

[0109] R=R c (p)-J m (σ)

[0110] Among them, J m (σ) is the correction term of the first stress invariant,

[0111] J m (σ)=η|trσ| l sgn(trσ);

[0112] R C (p) = Q[1-exp(-bp)], where Q and b are isotropic hardening parameters, η and l are asymmetric material parameters related to cyclic tension-compression asymmetry, trσ is the stress tensor trajectory, and sgn(x) represents the sign function, which takes the value of 1 for x>1 and −1 for x<1.

[0113] In this way, through the above embodiments, the present application combines the nonlinear kinematic hardening model to describe the ratchet effect in cyclic loading, and introduces a preset isotropic hardening rule to capture the cyclic tension-compression asymmetry, so as to realize the correction of the plastic strain module and obtain the target plastic strain module.

[0114] In an exemplary embodiment of the present application, the creep model of the creep strain module is corrected by a preset creep correction rule to obtain a target creep strain module. The specific steps may include:

[0115] Based on the preset creep correction rule, the equivalent creep strain related to the number of cycles is obtained;

[0116] The creep model of the creep strain module is modified based on the equivalent creep strain to obtain a target creep model for the evolution of the regenerative effect behavior in the first stage of creep, thus forming a target creep strain module.

[0117] In another exemplary embodiment, the target creep model is expressed as:

[0118]

[0119] in, is the equivalent creep strain of the ith cycle, λ and β are creep material parameters, ε pr,i is the creep strain increment at the transition point from the primary creep stage to the secondary creep stage within each holding cycle;

[0120]

[0121] Among them, C1, C2, χ1, χ2 are fitting parameters, ∈ ini is the initial equivalent plastic strain, ε rev,i-1 is the reverse plastic strain for each cycle.

[0122] In this way, through the above embodiments, the present application aims at the PCR behavior and realizes the correction of the creep strain module by dynamically adjusting the primary creep strain, which is manifested as quantifying the creep evolution under cyclic loading through the equivalent creep strain increment and the reverse plastic strain parameter.

[0123] In an exemplary embodiment of the present application, the target material parameters correspond one-to-one to various material parameters of the target non-unified constitutive model, including target elastic parameters, target viscoplastic material parameters, target isotropic hardening parameters, target asymmetric material parameters, target dynamic hardening material parameters, and target creep material parameters. The steps of obtaining the target material parameters of the preset type of the material to be tested through the preset material mechanical property test may specifically include:

[0124] Through uniaxial tensile tests, target elastic parameters and target viscoplastic material parameters are obtained;

[0125] Through strain-controlled cyclic tests, the target isotropic hardening parameters and target asymmetric material parameters are obtained by fitting.

[0126] The target dynamic hardening material parameters are obtained by inversion using the experimental data of the uniaxial ratchet test;

[0127] Through stress-controlled creep tests, the target creep material parameters are fitted.

[0128] In another exemplary embodiment, 316H stainless steel (S31609) at 650°C is predicted using a target non-unified constitutive model. First, the target material parameters of 316H stainless steel at 650°C are obtained. Specifically, the target elastic parameters E = 132.5 GPa, ν = 0.3, the initial yield stress σy = 112 MPa, and the target viscoplastic material parameters K0 = 37 MPa, n = 14.5 are obtained through uniaxial tensile testing. The target isotropic hardening parameters Q = 52 MPa, b = 46.59, as well as the target asymmetric material parameters η and l related to cyclic tension and compression asymmetry are determined based on the relationship between the peak stress evolution during strain-controlled cyclic loading. The target dynamic hardening material parameters ζ1 = 2227.46, μ = 0.48 are obtained by inversion based on the uniaxial ratchet test data. The target creep material parameter A = 1.75×10 -41 , λ = 0.95, β = 316.33. Then, the above target material parameters are substituted into the target non-unified constitutive model to predict the strain information of 316H stainless steel under high temperature environment of 650℃.

[0129] A stress test was conducted on 316H stainless steel at 650℃, and the predictions of the non-uniform constitutive model containing the first stage regeneration effect of creep as the target non-uniform constitutive model were compared with the test results. Figure 2 As shown, Figure 2 This is a schematic diagram comparing the creep strain predicted by the target non-uniform constitutive model and the test results in an exemplary embodiment of this application. It can be seen that the target non-uniform constitutive model with the regeneration effect of the first stage of creep successfully predicts the creep strain caused by the PCR effect and successfully reproduces the characteristics of PCR evolution during the cycle. Figure 3 As shown, Figure 3 Figure 2 is a schematic diagram comparing the strain-time response under test and the strain-time response predicted by the target non-uniform constitutive model in an exemplary embodiment of this application. It can be seen that the target non-uniform constitutive model of this application captures the overall trend of the maximum strain evolution, characterized by an initial rapid decrease followed by a gradual increase in subsequent cycles.

[0130] Figure 4 FIG. 4 is a block diagram of a stress prediction device 400 based on the creep first stage regeneration effect, as shown in an exemplary embodiment of the present application. Figure 4 As shown, the device includes:

[0131] A construction unit 401 is used to construct a total stress decomposition model for the material including the first stage creep regeneration effect, wherein the total stress decomposition model includes an elastic strain module, a plastic strain module, and a creep strain module;

[0132] The plastic strain correction unit 402 is used to correct the plastic strain module based on a preset nonlinear kinematic hardening model and an isotropic hardening rule to obtain a target plastic strain module;

[0133] The creep strain correction unit 403 is used to correct the creep model of the creep strain module by using a preset creep correction rule to obtain a target creep strain module;

[0134] A processing unit 404 is configured to obtain a target non-unified constitutive model based on the elastic strain module, the target plastic strain module, and the target creep strain module;

[0135] The test data acquisition unit 405 is used to obtain target material parameters of a preset type of the material to be tested through a preset material mechanical property test;

[0136] The prediction unit 406 is used to substitute the target material parameters into the target non-uniform constitutive model, and predict the strain information of the material to be tested under high temperature cyclic loading through the target non-uniform constitutive model.

[0137] The device applies the stress prediction method based on the regeneration effect of the first stage of creep provided in this application, and decomposes the total strain model into modules corresponding to elastic, plastic and creep strain components through the construction unit 401. In order to consider the PCR phenomenon during cyclic creep, the total strain decomposition model is adaptively corrected through the plastic strain correction unit 402 and the creep strain correction unit 403. The plastic strain module uses a nonlinear kinematic hardening model to describe the ratchet effect in cyclic loading, and introduces a preset isotropic hardening rule to capture the cyclic tension and compression asymmetry. The creep strain module uses the creep model to consider the PCR phenomenon during cyclic creep, so that the target non-unified constitutive model formed by the processing unit 404 after correction can assume that the complete PCR behavior occurs in each cycle, effectively capturing the asymmetric tension and compression behavior of the material during the cycle and the evolution of PCR, and providing a reliable description of the stress-strain response during cyclic creep loading. In this way, when applying the target non-uniform constitutive model, the prediction unit 406 can accurately predict the strain information under high-temperature cyclic load by substituting the target material parameters of the material to be tested obtained by the test data acquisition unit 405 into the corresponding parameter positions, thereby effectively predicting the creep behavior and experimental life of the material.

[0138] In another exemplary embodiment, the construction unit 401 is also used to construct an elastic strain module based on Hooke's law; construct a plastic strain module based on the viscoplastic flow equation; construct a creep strain module based on the primary-secondary creep model; and construct a total stress decomposition model containing the first stage creep regeneration effect for the material based on the elastic strain module, the plastic strain module and the creep strain module.

[0139] In another exemplary embodiment, the equation of the total stress decomposition model is:

[0140] ε=ε e +ε p +ε c

[0141] Among them, ε is the total strain decomposition model, and e, p, and c represent the components of elastic, plastic, and creep strains, respectively.

[0142] 4. The method according to claim 3, wherein the equation of the plastic strain module is:

[0143]

[0144] Among them, K and n are viscoplastic material parameters representing the viscosity of the material, Sa is the deviation between stress and back stress, σ y is the initial yield stress, and R is the isotropic hardening of the accumulated plastic strain.

[0145] In another exemplary embodiment, the plastic strain correction unit 402 is also used to correct the back stress component of the plastic strain module through a nonlinear motion hardening model to obtain a back stress component correction term, the nonlinear motion hardening model includes a back stress component superposition equation and a back stress component evolution equation; correct the isotropic hardening of the plastic strain module through a preset isotropic hardening rule to obtain an isotropic hardening correction term; apply the isotropic hardening correction term and the isotropic hardening correction term to the plastic strain module to obtain a target plastic strain module.

[0146] In another exemplary embodiment, the back stress component superposition equation of the nonlinear kinematic hardening model is:

[0147]

[0148] The back stress component evolution equation is:

[0149]

[0150] Where M is the total number of back stresses, ζ i , μ is the dynamic hardening material parameter, r i is the temperature material parameter related to back stress and temperature, and H() is the Heaviside step function.

[0151] In another exemplary embodiment, the implementation equation of the isotropic hardening rule is:

[0152] R=R c (p)-J m (σ)

[0153] Among them, J m (σ) is the first stress invariant,

[0154] J m (σ)=η|trσ| l sgn(trσ);

[0155] R C (p) = Q[1-exp(-bp)], where Q and b are isotropic hardening parameters, η and l are asymmetric material parameters related to cyclic tension-compression asymmetry, trσ is the stress tensor trajectory, and sgn(x) represents the sign function.

[0156] In another exemplary embodiment, the creep strain correction unit 403 is also used to obtain an equivalent creep strain related to the number of cycles based on a preset creep correction rule; based on the equivalent creep strain, the creep model of the creep strain module is corrected to obtain a target creep model for the evolution of the regenerative effect behavior in the first stage of creep, thereby forming a target creep strain module.

[0157] In another exemplary embodiment, the target creep model is expressed as:

[0158]

[0159] Δε pr,i =(1-F pcr )Δε pr,ini

[0160] in, is the equivalent creep strain of the ith cycle, λ and β are creep material parameters, ε pr,i is the creep strain increment at the transition point from the primary creep stage to the secondary creep stage within each holding cycle;

[0161]

[0162] Among them, C1, C2, χ1, χ2 are fitting parameters, ∈ ini is the initial equivalent plastic strain, ε rev,i-1 is the reverse plastic strain for each cycle.

[0163] In another exemplary embodiment, the target material parameters include target elastic parameters, target viscoplastic material parameters, target isotropic hardening parameters, target asymmetric material parameters, target dynamic hardening material parameters and target creep material parameters; the test data acquisition unit 405 is also used to obtain target elastic parameters and target viscoplastic material parameters through a uniaxial tensile test; to fit the target isotropic hardening parameters and target asymmetric material parameters through a strain-controlled cyclic test; to invert the target dynamic hardening material parameters through the test data of the uniaxial ratchet test; and to fit the target creep material parameters through a stress-controlled creep test.

[0164] It should be noted that the stress prediction device based on the first-stage regenerative effect of creep provided in the above-mentioned embodiment and the stress prediction method based on the first-stage regenerative effect of creep provided in the above-mentioned embodiment are based on the same concept. The specific manner in which each module and unit performs operations has been described in detail in the method embodiment and will not be repeated here. In actual applications, the stress prediction device based on the first-stage regenerative effect of creep provided in the above-mentioned embodiment can, as needed, allocate the above-mentioned functions to different functional modules, that is, divide the internal structure of the device into different functional modules to complete all or part of the functions described above, and this is not limited here.

[0165] An embodiment of the present application also provides an electronic device, comprising: one or more processors; a storage device for storing one or more programs, wherein when the one or more programs are executed by one or more processors, the electronic device implements the stress prediction method based on the first stage regeneration effect of creep provided in the above-mentioned embodiments.

[0166] Figure 5 The following is a schematic diagram showing the structure of a computer system suitable for implementing an electronic device according to an embodiment of the present application. Figure 5 The computer system 500 of the electronic device shown is only an example and should not bring any limitation to the functions and scope of use of the embodiments of the present application.

[0167] like Figure 5 As shown, the computer system 500 includes a central processing unit (CPU) 501, which can perform various appropriate actions and processes according to the program stored in the read-only memory (ROM) 502 or the program loaded from the storage part 508 into the random access memory (RAM) 503, such as executing the method in the above embodiment. Various programs and data required for system operation are also stored in the RAM 503. The CPU 501, ROM 502 and RAM 503 are connected to each other via a bus 504. An input / output (I / O) interface 505 is also connected to the bus 504.

[0168] The following components are connected to the I / O interface 505: an input section 506 including a keyboard, a mouse, and the like; an output section 507 including devices such as a cathode ray tube (CRT), a liquid crystal display (LCD), and a speaker; a storage section 508 including a hard disk; and a communication section 509 including a network interface card such as a LAN (Local Area Network) card or a modem. The communication section 509 performs communication processing via a network such as the Internet. A drive 510 is also connected to the I / O interface 505 as needed. Removable media 511, such as a magnetic disk, an optical disk, a magneto-optical disk, or a semiconductor memory, is installed in the drive 510 as needed, so that computer programs read therefrom can be installed into the storage section 508 as needed.

[0169] In particular, according to an embodiment of the present application, the process described above with reference to the flowchart can be implemented as a computer software program. For example, an embodiment of the present application includes a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program includes a computer program for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from a network via the communication section 509, and / or installed from a removable medium 511. When the computer program is executed by the central processing unit (CPU) 501, the various functions defined in the system of the present application are executed.

[0170] It should be noted that the computer-readable medium shown in the embodiments of the present application can be a computer-readable signal medium or a computer-readable storage medium or any combination of the above two. The computer-readable storage medium can be, for example, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or device, or any combination of the above. More specific examples of computer-readable storage media can include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM), a flash memory, an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present application, a computer-readable signal medium can include a data signal propagated in baseband or as part of a carrier wave, which carries a computer-readable computer program. This propagated data signal can take a variety of forms, including but not limited to an electromagnetic signal, an optical signal, or any suitable combination of the above. A computer-readable signal medium may also be any computer-readable medium other than a computer-readable storage medium that can transmit, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. A computer program embodied on a computer-readable medium may be transmitted using any suitable medium, including but not limited to wireless, wired, or any suitable combination thereof.

[0171] The flowcharts and block diagrams in the accompanying drawings illustrate the possible implementation architecture, functions and operations of the systems, methods and computer program products according to various embodiments of the present application. Among them, each box in the flowchart or block diagram can represent a module, program segment, or part of the code, and the above-mentioned module, program segment, or part of the code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in an order different from that marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram or flowchart, and the combination of boxes in the block diagram or flowchart, can be implemented with a dedicated hardware-based system that performs the specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0172] The units involved in the embodiments described in this application may be implemented by software or hardware, and the units described may also be set in a processor. In some cases, the names of these units do not constitute limitations on the units themselves.

[0173] Another aspect of the present application provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the aforementioned stress prediction method based on the creep first-stage regeneration effect. The computer-readable storage medium may be included in the electronic device described in the above embodiments, or may exist independently and not be incorporated into the electronic device.

[0174] Another aspect of the present application provides a computer program product or computer program, comprising computer instructions stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium and executes the computer instructions, causing the computer device to perform the stress prediction method based on the creep first-stage regeneration effect provided in each of the above-mentioned embodiments.

[0175] The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements or improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.< / x>

Claims

1. A stress prediction method based on the first stage regeneration effect of creep, characterized in that: The method comprises: Constructing a total stress decomposition model for the material including the first stage regeneration effect of creep, wherein the total stress decomposition model includes an elastic strain module, a plastic strain module, and a creep strain module; The plastic strain module is modified based on a preset nonlinear kinematic hardening model and an isotropic hardening rule to obtain a target plastic strain module; Correcting the creep model of the creep strain module by using a preset creep correction rule to obtain a target creep strain module; Obtaining a target non-unified constitutive model based on the elastic strain module, the target plastic strain module, and the target creep strain module; Obtain target material parameters of a preset type of material to be tested through a preset material mechanical property test; The target material parameters are substituted into the target non-uniform constitutive model, and the strain information of the material to be tested under high temperature cyclic loading is predicted by the target non-uniform constitutive model.

2. The method according to claim 1, characterized in that The total stress decomposition model containing the first stage creep regeneration effect for the material is constructed, and the total stress decomposition model includes an elastic strain module, a plastic strain module and a creep strain module, including: Based on Hooke's law, the elastic strain module is constructed; The plastic strain module is constructed based on the viscoplastic flow equation; The creep strain module is constructed based on the primary-secondary creep model; Based on the elastic strain module, the plastic strain module and the creep strain module, a total stress decomposition model including the first stage creep regeneration effect for the material is constructed.

3. The method according to claim 2, characterized in that The equation of the total stress decomposition model is: e=e e +e p +e c Among them, ε is the total strain decomposition model, and e, p, and c represent the components of elastic, plastic, and creep strains, respectively.

4. The method according to claim 3, characterized in that The equation of the plastic strain module is: Among them, K and n are viscoplastic material parameters representing the viscosity of the material, Sa is the deviation between stress and back stress, σ y is the initial yield stress, and R is the isotropic hardening of the accumulated plastic strain.

5. The method according to claim 1, wherein The plastic strain module is modified based on the preset nonlinear kinematic hardening model and isotropic hardening rule to obtain a target plastic strain module, including: Correcting the back stress component of the plastic strain module by a nonlinear motion hardening model to obtain a back stress component correction term, wherein the nonlinear motion hardening model includes a back stress component superposition equation and a back stress component evolution equation; Correcting the isotropic hardening of the plastic strain module using a preset isotropic hardening rule to obtain an isotropic hardening correction term; The isotropic hardening correction term and the isotropic hardening correction term are applied to the plastic strain module to obtain a target plastic strain module.

6. The method according to claim 5, characterized in that The back stress component superposition equation of the nonlinear kinematic hardening model is: The back stress component evolution equation is: Where M is the total number of back stresses, ζ i , μ is the dynamic hardening material parameter, r i is the temperature material parameter related to back stress and temperature, and H() is the Heaviside step function.

7. The method according to claim 5, characterized in that The realization equation of the isotropic hardening rule is: R=R c (p)-J m (s) Among them, J m (σ) is the first stress invariant, J m (σ)=η|trσ| l sgn(trσ);R C (p) = Q[1-exp(-bp)], where Q and b are isotropic hardening parameters, η and l are asymmetric material parameters related to cyclic tension-compression asymmetry, trσ is the stress tensor trajectory, and sgn(x) represents the sign function.

8. The method according to claim 1, characterized in that The creep model of the creep strain module is corrected by using a preset creep correction rule to obtain a target creep strain module, including: Based on the preset creep correction rule, the equivalent creep strain related to the number of cycles is obtained; The creep model of the creep strain module is modified based on the equivalent creep strain to obtain a target creep model for the evolution of the regenerative effect behavior in the first stage of creep, thereby forming a target creep strain module.

9. The method according to claim 8, characterized in that The target creep model is expressed as: No pr,i =(1-F pcr )No pr,ini in, is the equivalent creep strain of the ith cycle, λ and β are creep material parameters, ε pr,i is the creep strain increment at the transition point from the primary creep stage to the secondary creep stage within each holding cycle; Among them, C1, C2, χ1, χ2 are fitting parameters, ∈ ini is the initial equivalent plastic strain, ε rev,i-1 is the reverse plastic strain for each cycle.

10. The method according to claim 1, characterized in that The target material parameters include target elastic parameters, target viscoplastic material parameters, target isotropic hardening parameters, target asymmetric material parameters, target dynamic hardening material parameters and target creep material parameters; The method of obtaining target material parameters of a preset type of the material to be tested through a preset material mechanical property test includes: Through uniaxial tensile tests, target elastic parameters and target viscoplastic material parameters are obtained; Through strain-controlled cyclic tests, the target isotropic hardening parameters and target asymmetric material parameters are obtained by fitting. The target dynamic hardening material parameters are obtained by inversion using the experimental data of the uniaxial ratchet test; Through stress-controlled creep tests, the target creep material parameters are fitted.

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