Creep fatigue state evaluation method and system for high-temperature nuclear power device

Abstract

Provided in the present invention are a creep fatigue state evaluation method and system for a high-temperature nuclear power device, the creep fatigue state evaluation method for a high-temperature nuclear power device comprising: acquiring an isochronous stress-strain curve of a device, and, according to the isochronous stress-strain curve, deducing creep data and plastic strain data of device materials; according to the creep data of the device materials, calculating a creep constitutive parameter of the device materials; according to the creep constitutive parameter, performing non-elastic creep analysis to obtain a stress parameter and a strain parameter; performing, according to the stress parameter, equivalent stress calculation to obtain a time history of a corrected equivalent stress response in a life period, and, in view of a minimum rupture stress curve, calculating a creep damage; according to the strain parameter, performing equivalent strain calculation to obtain a strain range of each time point in the life period, and, in view of a fatigue curve, calculating a fatigue damage; and, according to the creep damage and the fatigue damage, estimating a creep fatigue state of the device. The present invention is simple and easy to implement, and reduces the conservativeness and complexity of estimation by means of elastic analysis methods.

Description

A creep fatigue state assessment method and system for high-temperature nuclear power equipment

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application No. 202310790182.6, filed on June 29, 2023, entitled “A creep fatigue state assessment method and system for high-temperature nuclear power equipment,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present invention relates to the technical field of life assessment of high-temperature nuclear power equipment, and in particular to a creep fatigue state assessment method and system for high-temperature nuclear power equipment. Background Art

[0004] Fourth-generation high-temperature reactors operate at temperatures as high as 600°C to 800°C. The long-term high-temperature service of components, coupled with creep deformation and stress relaxation, will severely impact the mechanical properties of materials and the lifespan of equipment. Therefore, the impact of high temperatures must be assessed during the design phase to optimize the design and manufacturing of equipment structures. Currently, strain, deformation, and fatigue assessments for high-temperature nuclear power equipment are mostly performed using elastic analysis methods. If the estimates fail, the structural design or system operating conditions are typically modified. However, these analytical methods are conservative, complex, costly, and time-consuming.

[0005] Therefore, how to reasonably and efficiently evaluate the creep fatigue state of high-temperature nuclear power equipment based on inelastic analysis methods has become an urgent problem to be solved in existing technologies.

[0006] Summary of the Invention

[0007] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a creep fatigue state assessment method and system for high-temperature nuclear power equipment, which has a simple process and is easy to implement, reduces the conservatism and complexity of the existing elastic analysis-based method, and improves the accuracy of the assessment.

[0008] In order to solve the above problems, the present invention mainly provides the following technical solutions:

[0009] In one aspect, the present invention provides a method for evaluating the creep fatigue state of high-temperature nuclear power equipment, comprising the following steps:

[0010] Step S1: obtaining an isochronous stress-strain curve of the device, and deriving creep data and plastic strain data of the device material according to the isochronous stress-strain curve;

[0011] Step S2: Calculating creep constitutive parameters of the equipment material according to the creep data of the equipment material;

[0012] Step S3: performing inelastic creep analysis according to the creep constitutive parameters to obtain the time history of stress parameters and strain parameters;

[0013] Step S4: performing an equivalent stress calculation based on the stress parameters to obtain a time history of a modified equivalent stress response within the service life, and calculating creep damage in combination with a minimum fracture stress curve; performing an equivalent strain calculation based on the strain parameters to obtain a strain range at each time point within the service life, and calculating fatigue damage in combination with a fatigue curve;

[0014] Step S5: estimating the creep fatigue state of the equipment based on the creep damage and the fatigue damage.

[0015] Preferably, in the step S1, the creep data corresponding to different stresses and different times are obtained according to the isochronous stress-strain curve.

[0016] Preferably, the step S2 includes the following steps:

[0017] Step S21: drawing a creep curve according to the creep data of the equipment material;

[0018] Step S22: constructing a creep parameterized model according to the key point information of the creep curve to obtain creep constitutive parameters of the equipment material.

[0019] Preferably, the total strain of the device material includes elastic strain, plastic strain and creep strain;

[0020] The elastic strain and the plastic strain are obtained from the thermal tensile curve of the isochronous stress-strain curve, and the creep strain is obtained from the isochronous stress-strain curves at different service times.

[0021] Preferably, in step S3,

[0022] When performing inelastic creep analysis, first establish a static analysis step, then a creep analysis step;

[0023] The strain parameters are restricted so that the maximum cumulative inelastic strain of the strain parameters averaged along the thickness does not exceed 1%; the surface strain caused by the equivalent linear distribution of the strain along the thickness does not exceed 2%; and the local strain at any point does not exceed 5%.

[0024] Preferably, in step S4, performing equivalent stress calculation based on stress parameters is performing equivalent stress calculation based on stress parameters at the dangerous point;

[0025] The performing equivalent strain calculation according to the strain parameters is performing equivalent strain calculation based on the strain parameters at the dangerous point.

[0026] Preferably, the step S5 includes the following steps:

[0027] Step S51: adding the creep damage and the fatigue damage, and determining whether the added sum satisfies the total creep-fatigue damage limit;

[0028] Step S52: On the premise that the total creep-fatigue damage limit is met, the creep damage and the fatigue damage are checked according to preset values; if the check passes, the high-temperature creep fatigue state assessment of the equipment is qualified; if the check fails, the high-temperature creep fatigue state assessment of the equipment is unqualified.

[0029] In a second aspect, the present invention provides a creep fatigue state assessment system for high-temperature nuclear power equipment, comprising:

[0030] A data acquisition module, configured to acquire isochronous stress and strain data of the equipment, and derive creep data and plastic strain data of the equipment material based on the isochronous stress and strain data;

[0031] A creep constitutive parameter calculation module, which calculates creep constitutive parameters of equipment materials based on the creep data;

[0032] An inelastic creep analysis module, performing inelastic creep analysis based on the creep constitutive parameters to obtain a time history of stress parameters and strain parameters;

[0033] An equivalent calculation module performs an equivalent stress calculation based on the stress parameters to obtain a time history of a modified equivalent stress response within the life cycle, and performs an equivalent strain calculation based on the strain parameters to obtain a strain range at each time point within the life cycle;

[0034] a damage calculation module, calculating creep damage according to the time history of the modified equivalent stress response and the minimum fracture stress curve, and calculating fatigue damage according to the strain range and the fatigue curve;

[0035] A state assessment module is used to estimate the creep fatigue state of the equipment by combining the creep damage and the fatigue damage.

[0036] In a third aspect, the present invention provides a computer-readable storage medium, in which a computer program is stored. The computer program is loaded by a processor of a terminal device and completes the steps described in the above-mentioned creep fatigue state assessment method for high-temperature nuclear power equipment.

[0037] In a fourth aspect, the present invention provides a terminal device comprising a processor and a computer-readable storage medium, wherein the memory stores a computer program, and when the processor executes the computer program, the steps described in the above-mentioned creep fatigue state assessment method for high-temperature nuclear power equipment are implemented.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] The present invention discloses a creep fatigue state assessment method and system for high-temperature nuclear power equipment. The method analyzes the strain and stress of high-temperature nuclear power equipment based on a non-elastic analysis method, thereby enabling an assessment of the impact of high temperature during the design phase. The process of the present invention is simple and easy to implement, which can reduce the conservatism and complexity of existing estimates based on elastic analysis methods and improve the accuracy of the assessment.

[0040] The present invention calculates equivalent stress and equivalent strain in different ways based on the stress and strain parameters obtained from the inelastic creep analysis, obtains creep damage and fatigue damage, and sets inelastic strain limits to ensure the rationality of creep fatigue assessment.

[0041] It should be understood that the foregoing general description and the following detailed description are merely illustrative and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments of the present application.

[0043] FIG1 is a flow chart of creep-fatigue state assessment in an embodiment of the present invention;

[0044] FIG2 is a schematic diagram of an isochronous stress-strain curve according to an embodiment of the present invention;

[0045] FIG3 is a flow chart of obtaining creep constitutive parameters in an embodiment of the present invention;

[0046] FIG4 is a schematic diagram of a creep curve according to an embodiment of the present invention;

[0047] FIG5 is a schematic diagram of a loading step setting according to an embodiment of the present invention;

[0048] FIG6 is a flow chart of calculating creep damage according to an embodiment of the present invention;

[0049] FIG7 is a schematic diagram of a modified equivalent stress curve in an embodiment of the present invention;

[0050] FIG8 is a flow chart of calculating the allowable creep time in an embodiment of the present invention;

[0051] FIG9 is a schematic diagram of a temperature curve in an embodiment of the present invention;

[0052] FIG10 is a schematic diagram showing a three-dimensional display of a minimum fracture stress curve according to an embodiment of the present invention;

[0053] FIG11 is a schematic diagram of a minimum fracture stress curve according to an embodiment of the present invention;

[0054] FIG12 is a schematic diagram of stress interpolation calculation in an embodiment of the present invention;

[0055] FIG13 is a schematic diagram of temperature interpolation calculation in an embodiment of the present invention;

[0056] FIG14 is a flow chart of calculating fatigue damage according to an embodiment of the present invention;

[0057] FIG15 is a schematic diagram of a fatigue curve according to an embodiment of the present invention;

[0058] FIG16 is a schematic diagram of a creep-fatigue limit line in an embodiment of the present invention;

[0059] FIG17 is a structural block diagram of a creep fatigue state assessment system for high-temperature nuclear power equipment according to an embodiment of the present invention.

[0060] Reference numerals: 1-data acquisition module; 2-creep constitutive parameter calculation module; 3-inelastic creep analysis module; 4-equivalent calculation module; 5-damage calculation module; 6-state assessment module; a-hot stretching curve; b-isochronous stress-strain curve after 30 hours of service; c-isochronous stress-strain curve after 300 hours of service; d-isochronous stress-strain curve after 3×10 3 Isochronous stress-strain curve of hr; e-service 3×10 4 Isochronous stress-strain curve of hr; f-service 3×10 5 hr's isochronous stress-strain curve; 31-static loading; 32-creep loading. DETAILED DESCRIPTION

[0061] In order to better understand the technical solution of the present application, the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0062] FIG1 is a flow chart of creep-fatigue state assessment according to an embodiment of the present invention.

[0063] This embodiment provides a method for evaluating the creep fatigue state of high-temperature equipment, as shown in FIG1 , including the following steps:

[0064] Step S1: obtaining an isochronous stress-strain curve of the device, and deriving creep data and plastic strain data of the device material according to the isochronous stress-strain curve;

[0065] Step S2: Calculating creep constitutive parameters of the equipment material according to the creep data of the equipment material;

[0066] Step S3: performing inelastic creep analysis according to the creep constitutive parameters to obtain the time history of stress parameters and strain parameters;

[0067] Step S4: performing an equivalent stress calculation based on the stress parameters to obtain a time history of a modified equivalent stress response within the service life, and calculating creep damage in combination with a minimum fracture stress curve; performing an equivalent strain calculation based on the strain parameters to obtain a strain range at each time point within the service life, and calculating fatigue damage in combination with a fatigue curve;

[0068] Step S5: estimating the creep fatigue state of the equipment based on the creep damage and the fatigue damage.

[0069] The following describes each step in detail.

[0070] Step S1: obtaining an isochronous stress-strain curve of the device, and deriving creep data and plastic strain data of the device material according to the isochronous stress-strain curve.

[0071] FIG2 is a schematic diagram of the isochronous stress-strain curves of an embodiment of the present invention (ASME Volume III, Section 5, Figure HBB-T-1800 provides isochronous stress-strain curves for specific materials). The hot stretching curve a only contains plastic strain and elastic strain, the isochronous stress-strain curve b after 30 hours of service, the isochronous stress-strain curve c after 300 hours of service, and the isochronous stress-strain curve after 3×10 3 Isochronous stress-strain curve d of hr, service 3×10 4 The isochronous stress-strain curve of hr and service 3×10 5 The isochronous stress-strain curve f of hr only contains creep strain and elastic strain.

[0072] As shown in Figure 2, creep data corresponding to different stresses and different times can be obtained based on the isochronous stress-strain curve. The total strain of the equipment material includes elastic strain, plastic strain and creep strain. Among them, the elastic strain and plastic strain are obtained from the hot stretching curve a in Figure 2, and the creep strain is obtained from the isochronous stress-strain curves of different service times except the hot stretching curve a in Figure 2 (isochronous stress-strain curve b for 30 hours of service, isochronous stress-strain curve c for 300 hours of service, and isochronous stress-strain curve c for 3×10 3 Isochronous stress-strain curve d of hr, service 3×10 4 Isochronous stress-strain curve of hr, service 3×10 5 The isochronous stress-strain curve f) of hr is obtained, and the specific expression is: ε T =ε e +ε p +ε c

[0073] Among them, ε T is the total strain of the device material, ε e is the elastic strain, ε p is the plastic strain, ε c is the creep strain.

[0074] Step S2: Calculating creep constitutive parameters of the equipment material according to the creep data of the equipment material.

[0075] FIG3 is a flow chart of obtaining creep constitutive parameters according to an embodiment of the present invention. Calculating creep constitutive parameters of equipment materials according to creep data of equipment materials includes:

[0076] Step S21: drawing a creep curve according to the creep data of the equipment material.

[0077] Step S22: constructing a creep parameterized model based on the key point information of the creep curve to obtain the creep constitutive parameters of the equipment material.

[0078] FIG4 is a schematic diagram of a creep curve according to an embodiment of the present invention.

[0079] According to the isochronous stress-strain curve in Figure 2, the creep strains at multiple stresses and different time periods can be derived: ε c =ε T -ε e

[0080] Thus, creep strain curves varying with time at different stress levels are obtained, as shown in FIG4 .

[0081] As shown in FIG4 , the creep constitutive parameters required by commercial mechanics software can be derived. In this embodiment, ABAQUS software is selected, and the Norton-Bailey creep parameterized constitutive model is adopted as follows:

[0082] Among them, A, n, and m are the creep constitutive parameters of the equipment material related to temperature, A is the Norton-Bailey coefficient, m is the time index, n is the stress index, σ is the stress, and t is the creep time.

[0083] According to the creep curves shown in Figure 4 under two sets of stress, the three key points P1(t1,ε c1 ,σ2),P2(t2,ε c2 ,σ2),P3(t2,ε c3 ,σ1), calculate:

[0084] Step S3: performing inelastic creep analysis according to the creep constitutive parameters to obtain time histories of stress parameters and strain parameters.

[0085] FIG5 is a schematic diagram of a loading step setting in an embodiment of the present invention.

[0086] In the process of performing inelastic creep analysis in combination with the Norton-Bailey creep parameterized constitutive model, as shown in FIG5 , static loading 31 is first performed, i.e., a static analysis step is established, such as a deadweight load, to establish an initial load; then creep loading 32 is performed, i.e., a creep analysis step is established, loads related to time and temperature are considered, and creep analysis is performed. While ensuring accuracy, the incremental steps can be minimized to improve computational efficiency.

[0087] In this embodiment, the strain parameters are restricted, and the calculated strain parameters must satisfy the following conditions: the average strain along the thickness of the maximum cumulative inelastic strain does not exceed 1%; the surface strain caused by the equivalent linear distribution of the strain along the thickness does not exceed 2%; and the local strain at any point does not exceed 5%.

[0088] Step S4: performing an equivalent stress calculation based on the stress parameters to obtain a time history of a modified equivalent stress response during the life cycle, and calculating creep damage in combination with the minimum fracture stress curve; performing an equivalent strain calculation based on the strain parameters to obtain a strain range at each time point during the life cycle, and calculating fatigue damage in combination with the fatigue curve.

[0089] In this embodiment, calculating the equivalent stress according to the stress parameters is calculating the equivalent stress based on the stress parameters at the dangerous point; and calculating the equivalent strain according to the strain parameters is calculating the equivalent strain based on the strain parameters at the dangerous point.

[0090] FIG6 is a flow chart of calculating creep damage in an embodiment of the present invention.

[0091] As shown in Figure 6, the calculation of creep damage includes the following steps:

[0092] Step S411: performing equivalent stress calculation based on the stress parameters at the dangerous point to obtain a time history of the corrected equivalent stress response within the life cycle.

[0093] In the above steps, the calculation of equivalent stress is based on the Mises stress and the principal stresses in the three directions at each moment during the life cycle at the critical point. The calculation of stress value is related to time, so the Mises stress and the principal stresses in the three directions can be calculated at each moment. Therefore, the time history of the equivalent stress response during the life cycle is calculated according to the following formula to obtain the equivalent stress, that is: J1=σ1+σ2+σ3

[0094] Among them, σ e is the equivalent stress, is the Mises stress, C is the material constant (e.g., for 316 stainless steel, C = 0.24), σ1, σ2, and σ3 are the principal stresses in the three directions respectively.

[0095] FIG7 is a schematic diagram of a modified equivalent stress curve in an embodiment of the present invention.

[0096] As shown in Figure 7, the equivalent stress curve after correction by the coefficient K′ (K′=0.67 for inelastic analysis) is divided into q time periods according to the time interval Δt, and the stress σ=σ at the corresponding moment is extracted. e K′, thus obtaining the time history of the modified equivalent stress response during the life cycle.

[0097] Figure 8 is a flow chart for calculating the allowable creep time in an embodiment of the present invention, Figure 9 is a schematic diagram of the temperature curve in an embodiment of the present invention, Figure 10 is a schematic diagram of the three-dimensional display of the minimum fracture stress curve in an embodiment of the present invention, Figure 11 is a schematic diagram of the minimum fracture stress curve in an embodiment of the present invention, Figure 12 is a schematic diagram of the stress interpolation calculation in an embodiment of the present invention, and Figure 13 is a schematic diagram of the temperature interpolation calculation in an embodiment of the present invention.

[0098] Step S412: As shown in FIG8 , calculating the allowable creep time includes the following steps:

[0099] Step S4121: Obtain the temperature T and stress σ corresponding to a certain moment t.

[0100] In the above steps, the stress σ corresponding to a certain moment t can be obtained from FIG7 ; FIG9 is a transient curve of time corresponding to temperature, from which the temperature T corresponding to a certain moment t can be obtained.

[0101] Step S4122: Find the previous set of temperatures T corresponding to a certain time t prev , calculate the previous set of temperatures T prev The corresponding allowable time The steps include:

[0102] Step S4122.1: As shown in Figure 10, the minimum fracture stress curve is composed of a specific set of temperatures, the corresponding minimum fracture stress, and the allowable time. Each set of temperatures corresponds to a set of data. In Figure 10, the previous set of temperatures T that is lower than the temperature T corresponding to a certain time t can be found. prev .

[0103] Step S4122.2: As shown in FIG10 , at the previous set of temperatures T prev Find the previous stress σ that is lower than the stress σ corresponding to a certain time t _prev and the subsequent stress σ higher than the stress σ corresponding to a certain time t _next .

[0104] Step S4122.3: As shown in Figure 11, which is a schematic diagram of the minimum fracture stress curve (ASME Volume III, Section 5, Table HBB-I-14.6 provides the minimum fracture stress strength of specific materials), find the previous set of temperatures Tprev and the previous stress σ _prev The corresponding previous allowed time T d_prev , the previous set of temperatures T prev and the latter stress σ _next The corresponding next allowed time T d_next .

[0105] Step S4122.4: As shown in Figure 12, obtain the stress σ corresponding to a certain time t at the previous set of temperatures T by linear interpolation. prev The corresponding allowable time Right now:

[0106] Among them, σ is the stress corresponding to a certain moment, σ _prev is the previous stress, σ _next is the latter stress, T d_prev is the previous allowed time, T d_next For the next time, It is the allowable time corresponding to the previous set of temperatures.

[0107] Step S4123: Find the next set of temperatures T corresponding to a certain time t next , calculate the next set of temperatures T next Corresponding allowable time The steps include:

[0108] Step S4123.1: Find the next set of temperatures T in FIG10 that are lower than the temperature T corresponding to a certain time t. next .

[0109] Step S4123.2: As shown in FIG10 , at the next set of temperatures T next Find the previous stress σ′ that is lower than the stress σ corresponding to a certain time t _prev and the subsequent stress σ′ higher than the stress σ corresponding to a certain time t _next .

[0110] Step S4123.3: As shown in FIG11 , find the next set of temperatures T next and the previous stress σ′ _prev The corresponding previous allowed time T' d_prev , the latter set of temperatures T next and the latter stress σ′ _next The corresponding next allowed time T' d_next .

[0111] Step S4123.4: As shown in Figure 12, obtain the stress σ corresponding to a certain time t at the next set of temperatures T by linear interpolation. next The corresponding allowable time The calculation principle is the same as the previous set of temperatures T in step S4122.4. prev The corresponding allowable time The calculation principle is the same as that of , and will not be repeated here.

[0112] Step S4124: As shown in FIG13 , the allowable creep time corresponding to the temperature T and stress σ at a certain time t is calculated:

[0113] Where T is the temperature corresponding to a certain moment t, (T d ) k is the allowable creep time, and k is the time interval.

[0114] Step S413: Calculate creep damage, namely:

[0115] Where q is the number of time intervals and Δt is the duration of time interval k.

[0116] FIG14 is a flow chart of calculating fatigue damage in an embodiment of the present invention.

[0117] As shown in Figure 14, the calculation of fatigue damage includes the following steps:

[0118] Step S421: performing equivalent strain calculation based on the strain parameters at the dangerous point to obtain the strain range.

[0119] In the above steps, the extreme state point of the cycle (maximum or minimum) is selected. The strain component of interest among the six strain components can be selected as the reference variable of the extreme point state. The time point is represented by the lower strain state as "0". The strain component at 0 is subtracted from the strain component corresponding to each time point i in the cycle process, and the equivalent strain range of each time point is calculated: Δε xi =ε xi -ε xo Δε yi =ε yi -ε yo Δε zi =ε zi -ε zo Δγ xyi =γ xyi -γ xyo Δγ xzi =γ xzi -γ xzo Δγ yzi =γ yzi -γ yzo

[0120] Among them, Δε equiv,i is the equivalent strain range at each time point, εxi , ε yi , ε zi , γ xyi , γ xzi , γ yzi represents the strain value at a certain moment, ε xo , ε yo , ε zo , γ xy i, γ xzi , γ yzi represents the strain value at the initial moment, Δε xi , Δε yi , Δε zi , Δγ xyi , Δγ xzi , Δγ yzi Represents the strain difference, inelastic analysis ν*=0.5.

[0121] Strain range ε t From the equivalent strain range at each time point Δε equiv,i The maximum value of ε is determined, that is, t =Δε max =max(ε equiv,i ).

[0122] FIG15 is a schematic diagram of a fatigue curve in an embodiment of the present invention (ASME Volume III, Section 5, Figure HBB-T-1420-1 provides fatigue curve data for specific materials).

[0123] Step S422: Select a corresponding fatigue curve according to the highest value of the corresponding temperature in the cycle, and calculate fatigue damage according to the fatigue curve and strain range.

[0124] In the above steps, as shown in Figure 15, the allowable fatigue times N corresponding to the strain range are calculated by interpolation based on the fatigue curve of the equipment material. d , calculate fatigue damage, that is:

[0125] Where P is the number of cycles, (n) j is the number of actions in the j-th cycle.

[0126] Step S5: estimating the creep fatigue state of the equipment based on creep damage and fatigue damage, including the following steps:

[0127] FIG16 is a schematic diagram of a creep-fatigue limit curve in an embodiment of the present invention (ASME Volume III, Section 5, Figure HBB-T-1420-2 provides creep-fatigue limit curves for specific materials).

[0128] Step S51: Add the creep damage and fatigue damage to determine whether the added sum satisfies the total creep-fatigue damage limit D shown in FIG16 . The sum of the creep damage and fatigue damage must satisfy the following relationship:

[0129] Step S52: On the premise of satisfying the total creep-fatigue damage limit, the creep damage and fatigue damage are checked according to the envelope shown in FIG16 .

[0130] In the above steps, when the creep-fatigue damage is within the envelope, it is called creep-fatigue damage. and If all conditions are met at the same time and the creep fatigue damage check is passed, the equipment can be considered to have passed the high-temperature creep fatigue state assessment; otherwise, it is unqualified and needs to be improved by changing the structural design, changing the load-bearing condition design, or reducing the design life, and then re-assessed after the improvement.

[0131] It should be noted that all stress and strain parameters in this embodiment meet the requirements of industry regulations. For example, the isochronous stress and strain material data should meet the requirements of ASME Volume III, Division 5; the creep constitutive parameters should meet the requirements of commercial mechanical analysis software; the strain meets the maximum cumulative inelastic strain requirements of ASME Volume III, Division 5; and the calculation and criterion of fatigue damage and creep damage meet the requirements of ASME Volume III, Division 5.

[0132] FIG17 is a structural block diagram of a creep fatigue state assessment system for high-temperature nuclear power equipment according to an embodiment of the present invention.

[0133] This embodiment provides a creep fatigue state assessment system for high-temperature nuclear power equipment, as shown in Figure 17, including a data acquisition module 1, a creep constitutive parameter calculation module 2, an inelastic creep analysis module 3, an equivalent calculation module 4, a damage calculation module 5 and a state assessment module 6 connected in sequence.

[0134] The data acquisition module 1 is configured to acquire isochronous stress and strain data of the device to be evaluated, and derive material creep data and plastic strain data based on the isochronous stress and strain data.

[0135] The creep constitutive parameter calculation module 2 is configured to calculate the creep constitutive parameters of the equipment material according to the creep data of the equipment material.

[0136] The inelastic creep analysis module 3 is configured to perform inelastic creep analysis according to creep constitutive parameters to obtain time histories of stress parameters and strain parameters.

[0137] The equivalent calculation module 4 is configured to perform equivalent stress calculation according to the stress parameters to obtain the time history of the modified equivalent stress response during the life cycle, and perform equivalent strain calculation according to the strain parameters to obtain the strain range at each time point during the life cycle.

[0138] The damage calculation module 5 is configured to calculate creep damage according to the time history of the modified equivalent stress response during the life cycle and the minimum fracture stress curve, and calculate fatigue damage according to the strain range and fatigue curve.

[0139] The condition assessment module 6 is configured to estimate the creep fatigue condition of the equipment by combining creep damage and fatigue damage.

[0140] This embodiment provides a computer-readable storage medium, in which a computer program is stored. The computer program is loaded by a processor of a terminal device and completes the steps of the above-mentioned creep fatigue state assessment method for high-temperature nuclear power equipment.

[0141] This embodiment provides a terminal device, including a processor and a computer-readable storage medium, wherein the memory stores a computer program. When the processor executes the computer program, the steps of the above-mentioned creep fatigue state assessment method for high-temperature nuclear power equipment are implemented.

[0142] The steps involved in the above-described creep fatigue state assessment system, computer-readable storage medium, and terminal device for high-temperature nuclear power equipment correspond to the creep fatigue state assessment method for high-temperature nuclear power equipment. For detailed implementation, please refer to the relevant description of the creep fatigue state assessment method for high-temperature nuclear power equipment. The term "computer-readable storage medium" should be understood to mean a single medium or multiple media containing one or more instruction sets; it should also be understood to include any medium capable of storing, encoding, or carrying an instruction set for execution by a processor and causing the processor to perform any method of the present invention.

[0143] Those skilled in the art will appreciate that the modules or steps of the present invention described above can be implemented using a general-purpose computer device. Alternatively, they can be implemented using program code executable by a computing device, which can then be stored in a storage device and executed by the computing device. Alternatively, they can be fabricated into separate integrated circuit modules, or multiple modules or steps can be fabricated into a single integrated circuit module for implementation. The present invention is not limited to any specific combination of hardware and software.

[0144] Although the above describes the specific embodiments of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without any creative work are still within the scope of protection of the present invention.

Claims

1. A creep fatigue state assessment method for high temperature nuclear power equipment, characterized in that: The steps include: Step S1: obtaining an isochronous stress-strain curve of the equipment, and deriving creep data and plastic strain data of the equipment material according to the isochronous stress-strain curve; Step S2: Calculating creep constitutive parameters of the equipment material according to the creep data of the equipment material; Step S3: performing inelastic creep analysis according to the creep constitutive parameters to obtain the time history of stress parameters and strain parameters; Step S4: performing equivalent stress calculation according to the stress parameters to obtain the time history of the modified equivalent stress response during the service life, and calculating the creep damage in combination with the minimum fracture stress curve; performing equivalent strain calculation according to the strain parameters to obtain the strain range at each time point during the service life, and calculating the fatigue damage in combination with the fatigue curve; Step S5: estimating the creep fatigue state of the equipment according to the creep damage and the fatigue damage.

2. The creep fatigue state assessment method for high temperature nuclear power equipment according to claim 1, characterized in that: In step S1, The creep data corresponding to different stresses and different times are obtained according to the isochronous stress-strain curve.

3. The creep fatigue state assessment method for high temperature nuclear power equipment according to claim 1, characterized in that: In step S2, the following steps are included: Step S21: drawing a creep curve according to the creep data of the equipment material; Step S22: construct a creep parameterized model based on the key point information of the creep curve to obtain Creep constitutive parameters of equipment materials.

4. The creep fatigue state assessment method for high temperature nuclear power equipment according to claim 1, characterized in that: The total strain of the equipment material includes elastic strain, plastic strain and creep strain; The elastic strain and the plastic strain are obtained from the thermal tensile curve of the isochronous stress-strain curve, and the creep strain is obtained from the isochronous stress-strain curve at different service times.

5. The creep fatigue state assessment method for high temperature nuclear power equipment according to claim 1, characterized in that: In step S3, When performing inelastic creep analysis, first establish a static analysis step, then establish a creep analysis step; The strain parameters are restricted so that the average strain along the thickness of the maximum accumulated inelastic strain of the strain parameters does not exceed 1%; the surface strain caused by the equivalent linear distribution of the strain along the thickness does not exceed 2%; and the local strain at any point does not exceed 5%.

6. The creep fatigue state assessment method for high temperature nuclear power equipment according to claim 1, characterized in that: In step S4, The equivalent stress calculation according to the stress parameters is to calculate the equivalent stress based on the stress parameters at the dangerous point; The performing equivalent strain calculation according to the strain parameters is performing the equivalent strain calculation based on the strain parameters at the dangerous point.

7. The creep fatigue state assessment method for high temperature nuclear power equipment according to claim 1, characterized in that: In step S5, the following steps are included: Step S51: adding the creep damage and the fatigue damage, and determining whether the added sum satisfies the total creep-fatigue damage limit; Step S52: On the premise of satisfying the total creep-fatigue damage limit, the creep damage and the fatigue damage are checked according to preset values; if the check passes, the high-temperature creep fatigue state evaluation of the equipment is qualified; if the check fails, the high-temperature creep fatigue state evaluation of the equipment is unqualified.

8. A creep fatigue state assessment system for high temperature nuclear power equipment, characterized in that: include: A data acquisition module, used to acquire isochronous stress-strain data of the equipment, and derive creep data and plastic strain data of the equipment material according to the isochronous stress-strain data; A creep constitutive parameter calculation module, which calculates the creep constitutive parameters of the equipment material according to the creep data; An inelastic creep analysis module, which performs inelastic creep analysis according to the creep constitutive parameters to obtain a time history of stress parameters and strain parameters; An equivalent calculation module, performing an equivalent stress calculation according to the stress parameters to obtain a time history of a modified equivalent stress response during the life cycle, and performing an equivalent strain calculation according to the strain parameters to obtain a strain range at each time point during the life cycle; A damage calculation module, which calculates creep damage according to the time history of the modified equivalent stress response and the minimum fracture stress curve, and calculates fatigue damage according to the strain range and the fatigue curve; The state assessment module is used to estimate the creep fatigue state of the equipment by combining the creep damage and the fatigue damage.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, which is loaded by a processor of a terminal device and completes the creep fatigue state assessment method for high-temperature nuclear power equipment according to any one of claims 1 to 7.

10. A terminal device, characterized in that: It comprises a processor and a computer-readable storage medium, wherein the memory stores a computer program, and when the processor executes the computer program, the creep fatigue state assessment method of high-temperature nuclear power equipment according to any one of claims 1 to 7 is implemented.

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