EP-4738176-A1 - CREEP FATIGUE STATE EVALUATION METHOD AND SYSTEM FOR HIGH-TEMPERATURE NUCLEAR POWER DEVICE

EP4738176A1EP 4738176 A1EP4738176 A1EP 4738176A1EP-4738176-A1

Abstract

Provided in the present application 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 the device, and deducing creep data and plastic strain data of device materials according to the isochronous stress-strain curve; calculating creep constitutive parameters of the device materials according to the creep data of the device materials; performing inelastic creep analysis according to the creep constitutive parameters to acquire a time history of a stress parameter and a strain parameter; performing equivalent stress calculation according to the stress parameter to acquire a time history of a corrected equivalent stress response during service life, and calculating a creep damage in view of a minimum fracture stress curve; performing equivalent strain calculation according to the strain parameter to acquire a strain range of each time point during service life, and calculating a fatigue damage in view of a fatigue curve; and estimating a creep fatigue state of the device according to the creep damage and the fatigue damage. The present application is simple and easy to implement, and reduces the conservativeness and complexity of estimation by means of elastic analysis methods.

Inventors

PAN, Keqi
ZHOU, Shaochong
YIN, HAIFENG
HU, Zhelin
LI, JUAN
LU, QIANG
CHEN, XINGWEN
FENG, Shaodong

Assignees

Shanghai Nuclear Engineering Research & Design Institute Co., Ltd.

Dates

Publication Date: 20260506
Application Date: 20240430

Claims (10)

A creep fatigue state evaluation method for a high-temperature nuclear power device, comprising following steps: step S1: acquiring an isochronous stress-strain curve of the device, and deducing creep data and plastic strain data of device materials according to the isochronous stress-strain curve; step S2: calculating creep constitutive parameters of the device materials according to the creep data of the device materials; step S3: performing inelastic creep analysis according to the creep constitutive parameters to acquire a time history of a stress parameter and a strain parameter; step S4: performing equivalent stress calculation according to the stress parameter to acquire a time history of a corrected equivalent stress response during service life, and calculating a creep damage based on a minimum fracture stress curve; performing equivalent strain calculation according to the strain parameter to acquire a strain range at each time point during service life, and calculating a fatigue damage based on a fatigue curve; and step S5: estimating the creep fatigue state of the device according to the creep damage and the fatigue damage.
The creep fatigue state evaluation method for a high-temperature nuclear power device according to claim 1, wherein in step S1, the creep data corresponding to different stresses and different times are acquired according to the isochronous stress-strain curve.
The creep fatigue state evaluation method for a high-temperature nuclear power device according to claim 1, wherein following steps are included in step S2: step S21: drawing a creep curve according to the creep data of the device materials; and step S22: constructing a creep parameterized model according to key point information of the creep curve to acquire the creep constitutive parameters of the device materials.
The creep fatigue state evaluation method for a high-temperature nuclear power device according to claim 1, wherein a total strain of the device materials includes elastic strain, plastic strain and creep strain, the elastic strain and the plastic strain are acquired from a thermal tensile curve of the isochronous stress-strain curve, and the creep strain is acquired from the isochronous stress-strain curves corresponding to different service times.
The creep fatigue state evaluation method for a high-temperature nuclear power device according to claim 1, wherein in step S3, when performing the inelastic creep analysis, a static analysis step is first established, then a creep analysis step is established, the strain parameter is restricted, so that a strain averaged along a thickness of a maximum accumulated inelastic strain of the strain parameter does not exceed 1%; a surface strain caused by an equivalent linear distribution of the strain along the thickness does not exceed 2%; and a local strain at any point does not exceed 5%.
The creep fatigue state evaluation method for a high-temperature nuclear power device according to claim 1, wherein in step S4, performing equivalent stress calculation according to the stress parameter is implemented by performing equivalent stress calculation based on the stress parameter at a critical point; and performing equivalent strain calculation according to the strain parameter is implemented by performing equivalent strain calculation based on the strain parameter at the critical point.
The creep fatigue state evaluation method for a high-temperature nuclear power device according to claim 1, wherein following steps are comprised in step S5: step S51: adding the creep damage and the fatigue damage, and determining whether a resulted sum satisfies a total creep-fatigue damage limit; step S52: checking, under a premise of satisfying the total creep-fatigue damage limit, the creep damage and the fatigue damage according to preset values; evaluating, if the checking is passed, a high-temperature creep fatigue state of the device as qualified; and evaluating, if the checking is failed, the high-temperature creep fatigue state of the device as unqualified.
A creep fatigue state evaluation system for a high-temperature nuclear power device, comprising: a data acquisition module, configured to acquire isochronous stress-strain data of the device, and deduce creep data and plastic strain data of device materials according to the isochronous stress-strain data; a creep constitutive parameter calculation module, configured to calculate creep constitutive parameters of the device materials according to the creep data; a inelastic creep analysis module, configured to perform inelastic creep analysis according to the creep constitutive parameters to acquire a time history of a stress parameter and a strain parameter; an equivalent calculation module, configured to perform equivalent stress calculation according to the stress parameter to acquire a time history of a corrected equivalent stress response during service life, and perform equivalent strain calculation according to the strain parameter to acquire a strain range of each time point during service life; a damage calculation module, configured to calculate a creep damage according to the time history of the corrected equivalent stress response and a minimum fracture stress curve, and calculate a fatigue damage according to the strain range and a fatigue curve; and a state evaluation module, configured to estimate the creep fatigue state of the device by combining the creep damage and the fatigue damage.
A computer-readable storage medium, wherein a computer program is stored in the computer-readable storage medium, and the computer program is loaded by a processor of a terminal device to implement the creep fatigue state evaluation method for a high-temperature nuclear power device according to any one of claims 1 to 7.
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 creep fatigue state evaluation method for a high-temperature nuclear power device according to any one of claims 1 to 7 is implemented.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application claims priority to Chinese patent application No. 202310790182.6, filed on June 29, 2023 and entitled "CREEP FATIGUE STATE EVALUATION METHOD AND SYSTEM FOR HIGH-TEMPERATURE NUCLEAR POWER DEVICE", which is incorporated herein by reference in its entirety. TECHNICAL FIELD The present application relates to the technical field of service life evaluation for high-temperature nuclear power device, and in particular to a creep fatigue state evaluation method and system for a high-temperature nuclear power device. BACKGROUND The operating temperature of the fourth-generation high-temperature reactor reaches up to 600°C~800°C. During the long-term high-temperature service of components, coupled with factors such as creep deformation and stress relaxation, the mechanical properties of materials and the service life of devices will be seriously affected. Therefore, it is necessary to evaluate the impact of high-temperature in the design stage to promote the optimization of device structure design and processing and manufacturing. Currently, elastic analysis methods are mostly used for evaluating the strain, deformation and fatigue of a high-temperature nuclear power device, and if the evaluation fails, the structural design or system operating conditions are usually directly modified. However, the above analysis methods are relatively conservative and the process is not only complicated, but also costly and time-consuming. Therefore, how to reasonably and efficiently evaluate the creep fatigue state of the high-temperature nuclear power device based on inelastic analysis methods has become an urgent issue to be solved in the existing technology. SUMMARY In view of the shortcomings of the prior art, the purpose of the present application is to provide a creep fatigue state evaluation method and system for a high-temperature nuclear power device, which features a simple process and easy implementation, reduces the conservatism and complexity of the existing elastic analysis method-based estimation, and improves the accuracy of the evaluation. In order to solve the above issue, the present application mainly provides the following technical solutions: In an aspect, the present application provides a creep fatigue state evaluation method for a high-temperature nuclear power device, including the following steps: step S1: acquiring an isochronous stress-strain curve of the device, and deducing creep data and plastic strain data of device materials according to the isochronous stress-strain curve;step S2: calculating creep constitutive parameters of the device materials according to the creep data of the device materials;step S3: performing inelastic creep analysis according to the creep constitutive parameters to acquire a time history of a stress parameter and a strain parameter;step S4: performing equivalent stress calculation according to the stress parameter to acquire a time history of a corrected equivalent stress response during service life, and calculating a creep damage based on a minimum fracture stress curve; performing equivalent strain calculation according to the strain parameter to acquire a strain range at each time point during service life, and calculating a fatigue damage based on a fatigue curve; andstep S5: estimating the creep fatigue state of the device according to the creep damage and the fatigue damage. Preferably, in step S1, the creep data corresponding to different stresses and different times are acquired according to the isochronous stress-strain curve. Preferably, following steps are included in step S2: step S21: drawing a creep curve according to the creep data of the device materials; andstep S22: constructing a creep parameterized model according to key point information of the creep curve to acquire the creep constitutive parameters of the device materials. Preferably, a total strain of the device materials includes elastic strain, plastic strain and creep strain, wherein the elastic strain and the plastic strain are acquired from a thermal tensile curve of the isochronous stress-strain curve, and the creep strain is acquired from the isochronous stress-strain curves corresponding to different service times. Preferably, in step S3, when performing the inelastic creep analysis, a static analysis step is first established, then a creep analysis step is established,wherein the strain parameter is restricted, so that a strain averaged along a thickness of a maximum accumulated inelastic strain of the strain parameter does not exceed 1%; a surface strain caused by an equivalent linear distribution of the strain along the thickness does not exceed 2%; and a local strain at any point does not exceed 5%. Preferably, in step S4, performing equivalent stress calculation based on the stress parameter is implemented by performing equivalent stress calculation based on the stress parameter at a critical point; and performing equivalent strain