CN115577582A - Method and device for evaluating service life of repaired multi-crack cast steel component - Google Patents
Method and device for evaluating service life of repaired multi-crack cast steel component Download PDFInfo
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- G06F2119/02—Reliability analysis or reliability optimisation; Failure analysis, e.g. worst case scenario performance, failure mode and effects analysis [FMEA]
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Abstract
The invention relates to a method and a device for evaluating the service life of a repaired multi-crack cast steel component, wherein the method comprises the steps of setting a stress concentration area of the component to be evaluated through a preset finite element model, and presetting a virtual crack according to the characteristic dimension of a typical buried crack acquired in the repairing process of the component to be evaluated; and performing calculation and analysis on a stress field in a preset area, based on fracture mechanics, adopting a failure evaluation graph method to evaluate and calculate whether the preset crack can generate destabilization expansion under the current service condition according to an analysis result, resetting a predicted service period shorter than the predicted service period when the evaluation result of the part to be evaluated is dangerous in the predicted service period, and adopting the failure evaluation graph method again to evaluate and calculate whether the new crack expanded in the predicted service period can generate destabilization expansion under the current service condition. The invention can evaluate the service life of the repaired cast steel part and prevent the equipment from cracking in the using process to cause safety problems.
Description
Technical Field
The invention belongs to the technical field of life prediction, and particularly relates to a method and a device for evaluating the service life of a repaired multi-crack cast steel component.
Background
Enterprises such as coal-fired power plants, chemical plants and the like use a large amount of thick-walled metal parts made of cast steel as through-flow parts of high-temperature and high-pressure flowing working media (such as supercritical water steam), such as main steam block valves, high-pressure automatic main valves, steam turbine cylinders and the like. In the long-term service process of the thick-wall metal part, the temperature and the pressure of the internal working medium are periodically changed, such as starting and stopping of equipment, peak shaving operation of a coal-fired power plant and the like. When the temperature of the working medium changes, a certain time is needed for heat transfer in the wall thickness direction of the component, so that a certain temperature difference is generated between the inner wall and the outer wall of the component. At different temperatures, the thermal expansion of the steel material varies, causing a constraining thermal stress in the component metal material. Generally, the faster the temperature change of the working substance, the greater the thermal stress that is caused. This cyclic variation in thermal stress is a major cause of thermal fatigue damage to thick-walled metal components. Thermal fatigue damage causes a reduction in the load-bearing properties of the metal material.
After the thick-wall cast steel high-temperature pressure-bearing component is subjected to long-term thermal fatigue damage, a plurality of parts are easy to crack and lose efficacy, and the number of cracks of one high-pressure automatic main valve can reach dozens or hundreds. And related researches show that the casting defects such as sand holes, shrinkage cavities, looseness and the like inevitably exist in the metal of the cast steel part, so that the buried cracks which do not extend to the surface of the part exist in the part under the action of long-term thermal fatigue stress.
The large crystal grains of the cast steel material have serious attenuation effect on the ultrasonic wave adopted by nondestructive testing; and various casting defects existing inside the parts are also liable to cause interference with ultrasonic flaw detection signals. Therefore, it is difficult to know whether or not crack defects exist in the metal of the cast steel member by a non-destructive inspection method.
The cracks that have been found in the above-mentioned parts are usually removed by mechanical grinding, and the size of the removed part is restored by welding. However, for the buried cracks possibly existing in other parts of the component, effective methods cannot be adopted for flaw detection and discovery, and the service life problem of the buried cracks which are not discovered and processed cannot be known, so that repeated cracking of the equipment can be caused, and the method becomes a great potential safety hazard.
Disclosure of Invention
In view of the above, the present invention provides a method and an apparatus for evaluating the lifetime of a repaired multi-crack cast steel component to solve the problem that the lifetime of the buried cracks that are not discovered and treated cannot be known in the prior art.
In order to achieve the purpose, the invention adopts the following technical scheme: a method for evaluating the life of a multi-cracked cast steel part after repair, comprising:
setting a stress concentration area of a component to be evaluated through a preset finite element model, and setting at least one preset virtual crack with the same size as the characteristic size in the stress concentration area according to the characteristic size of a typical buried crack obtained in the repair process of the component to be evaluated;
calculating and analyzing the stress field of the preset virtual crack in a preset area, and evaluating and calculating whether the preset crack can generate destabilization expansion under the current service condition by adopting a failure evaluation graph method according to the analysis result based on fracture mechanics; if the analysis result represents that the preset crack can be unstably expanded under the current service condition, the evaluation result of the part to be evaluated is dangerous under the current condition; otherwise, the evaluation result of the part to be evaluated is safe under the current condition;
and when the evaluation result of the part to be evaluated is the danger in the expected service period, resetting the expected service period shorter than the expected service period, and evaluating and calculating whether the new crack expanded in the expected service period is subjected to unstable expansion under the current service condition by adopting a failure evaluation graph method again.
Further, the feature sizes include:
buried depth, length and width.
Further, the evaluation calculation of whether the preset crack can be unstably expanded under the current service condition by adopting a failure evaluation graph method based on fracture mechanics according to the analysis result comprises the following steps:
crack propagation calculations controlled by high temperature creep factors, and crack propagation calculations controlled by thermal fatigue factors.
Further, the resetting of the predicted service period shorter than the predicted service period and the evaluation and calculation of whether the new crack expanded in the predicted service period will be unstably expanded under the current service condition by using the failure evaluation graph method again include:
after acquiring the characteristic size of a new crack which is expanded after the end of the expected service period, evaluating and calculating whether the new crack can be unstably expanded or not under the current service condition by adopting a failure evaluation graph method again; if the analysis result represents that the preset crack can be unstably expanded under the current service condition, the evaluation result of the part to be evaluated is a risk in the expected service period; otherwise, the evaluation result of the part to be evaluated is safety in the expected service period.
Further, when the evaluation life of the part to be evaluated is dangerous,
and repairing or replacing the part to be evaluated.
The embodiment of the application provides a life evaluation device after multi-crack cast steel part is restoreed, includes:
the system comprises a presetting module, a detection module and a control module, wherein the presetting module is used for setting a stress concentration area of a part to be evaluated through a preset finite element model, and setting at least one preset virtual crack with the same characteristic size in the stress concentration area according to the characteristic size of a typical buried crack obtained in the process of repairing the part to be evaluated;
the calculation and analysis module is used for calculating and analyzing the stress field of the preset virtual crack in a preset area, and evaluating and calculating whether the preset virtual crack can be subjected to destabilization expansion under the current service condition by adopting a failure evaluation graph method according to the analysis result based on fracture mechanics; if the analysis result represents that the preset crack can be unstably expanded under the current service condition, the evaluation result of the part to be evaluated is dangerous under the current condition; otherwise, the evaluation result of the part to be evaluated is safe under the current condition;
and the evaluation processing module is used for resetting the predicted service period shorter than the predicted service period when the evaluation result of the part to be evaluated is the risk in the predicted service period, and evaluating and calculating whether the new crack expanded in the predicted service period can be unstably expanded under the current service condition by adopting a failure evaluation graph method again.
An embodiment of the present application provides a computer device, including: a memory storing a computer program that, when executed by the processor, causes the processor to perform the steps of the method for evaluating a lifetime of a multi-crack cast steel component after repair as provided in any of the above embodiments.
The embodiment of the application also provides a computer storage medium, which stores a computer program, and when the computer program is executed by a processor, the processor executes the steps of the method for evaluating the service life of the repaired multi-crack cast steel component provided by any one of the embodiments.
By adopting the technical scheme, the invention can achieve the following beneficial effects:
the invention provides a method and a device for evaluating the service life of a repaired multi-crack cast steel component, wherein the method comprises the steps of setting a stress concentration area of the component to be evaluated through a preset finite element model, and presetting a virtual crack according to the characteristic dimension of a typical buried crack acquired in the repairing process of the component to be evaluated; and performing calculation and analysis on a stress field in a preset area, based on fracture mechanics, adopting a failure evaluation graph method to evaluate and calculate whether the preset crack can generate destabilization expansion under the current service condition according to an analysis result, resetting a predicted service period shorter than the predicted service period when the evaluation result of the part to be evaluated is dangerous in the predicted service period, and adopting the failure evaluation graph method again to evaluate and calculate whether the new crack expanded in the predicted service period can generate destabilization expansion under the current service condition. The invention can evaluate the service life of the repaired cast steel part and prevent the equipment from cracking in the using process to cause safety problems.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the prior art descriptions will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
FIG. 1 is a schematic step diagram of the method for evaluating the service life of a multi-crack cast steel part after repair according to the present invention;
FIG. 2 is a schematic diagram of a predetermined crack of a regularized characterization provided by the present invention;
FIG. 3 is a schematic diagram of the evaluation result of the FAD map of the preset crack under the service condition provided by the invention;
FIG. 4 is a schematic view of a crack on the circumferential surface of the inner surface formed after propagation of a predetermined crack provided by the present invention;
FIG. 5 is the FAD map evaluation result of the new crack after expansion under the service condition;
FIG. 6 is a schematic structural view of a life evaluation apparatus after repairing a multi-cracked cast steel part according to the present invention;
fig. 7 is a schematic hardware structure diagram of the operating environment of the method for evaluating the service life of a multi-crack cast steel component after repair.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be described in detail below. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the examples given herein without any inventive step, are within the scope of the present invention.
In the related technology, 62 cracks are found on the surface of the inner wall of the valve casing when the high-pressure automatic main valve is stopped and repaired, and about 394 new cracks are found in the process of eliminating the defects by adopting a mechanical grinding method. According to the specifications of the repair welding technology of the DL/T753-2015 steam turbine steel casting, the size of the part of the valve casing which is eliminated is repaired by adopting a welding method. Before the unit is started, the safety and the service life of the components need to be evaluated in order to solve the possible existence of buried cracks.
The following describes a specific method and apparatus for evaluating the life of a multi-crack cast steel component after repair, provided in the embodiments of the present application, with reference to the accompanying drawings.
As shown in fig. 1, the method for evaluating the life of a multi-crack cast steel component after repair provided in the embodiment of the present application includes:
s101, setting a stress concentration area of a component to be evaluated through a preset finite element model, and setting at least one preset virtual crack with the same size as a characteristic size in the stress concentration area according to the characteristic size of a typical buried crack obtained in the repair process of the component to be evaluated;
stress concentration refers to the phenomenon of local increase of stress in an object, and generally occurs in places with sharp changes of the shape of the object, such as notches, holes, grooves and places with rigid constraints. Stress concentration can cause fatigue cracks on the object and also can cause static load fracture of parts made of brittle materials, and the maximum value (peak stress) of the stress at the stress concentration is related to factors such as the geometric shape and the loading mode of the object.
It is noted that in this application, the typical locations and characteristic dimensions of burial cracks are found during the ablation process.
S102, calculating and analyzing a stress field of the preset virtual crack in a preset area, and evaluating and calculating whether the preset virtual crack can be subjected to destabilization expansion under the current service condition by adopting a failure evaluation graph method according to an analysis result based on fracture mechanics; if the analysis result represents that the preset crack can be unstably expanded under the current service condition, the evaluation result of the part to be evaluated is dangerous under the current condition; otherwise, the evaluation result of the part to be evaluated is safe under the current condition;
the finite element model is a model established by using a finite element analysis method, and is a group of unit combinations which are only connected at nodes, only transmit force by virtue of the nodes and are only restrained at the nodes. Wherein the preset crack is a virtual crack.
S103, when the evaluation result of the part to be evaluated is the danger in the expected service period, resetting the expected service period shorter than the expected service period, and evaluating and calculating whether the new crack expanded in the expected service period is subjected to instability expansion under the current service condition by adopting a failure evaluation graph method again.
According to the method and the device, the stress field calculation can be carried out on the area around the preset crack through the finite element model by constructing the finite element model, so that the service life of the part to be evaluated is evaluated according to the calculation and analysis result. The predetermined region is a region near the predetermined crack.
The working principle of the method for evaluating the service life of the repaired multi-crack cast steel part is as follows: firstly, setting a stress concentration area of a component to be evaluated through a preset finite element model, and setting at least one preset virtual crack with the same characteristic size in the stress concentration area according to the characteristic size of a typical buried crack obtained in the repair process of the component to be evaluated; calculating and analyzing a stress field of the preset virtual crack in a preset area, and evaluating and calculating whether the preset crack can generate destabilization expansion under the current service condition by adopting a failure evaluation graph method according to an analysis result based on fracture mechanics; if the analysis result represents that the preset crack can be unstably expanded under the current service condition, the evaluation result of the part to be evaluated is dangerous under the current condition; otherwise, the evaluation result of the part to be evaluated is safe under the current condition; and when the evaluation result of the part to be evaluated is the danger in the predicted service period, resetting the predicted service period shorter than the predicted service period, and evaluating and calculating whether the new crack expanded in the predicted service period is subjected to unstable expansion under the current service condition by adopting a failure evaluation graph method again.
Preferably, the characteristic dimensions include:
buried depth, length and width.
In the related art, when the number of the cracks is two, whether the distance between the two cracks is larger than a preset depth is judged; if the distance between the two cracks is larger than the preset depth, respectively carrying out calculation analysis on the two cracks; and if the distance between the two cracks is smaller than or equal to the preset depth, combining the two cracks into one combined crack, and performing calculation analysis on the combined crack.
Specifically, the preset depth is 5mm, the two cracks are set to be two in the application, the two cracks have the same size, as shown in fig. 2, the application firstly judges that the distance between the two cracks of the two cracks is greater than the half-depth of the crack by 5mm, the two cracks are not in accordance with the crack merging condition, and the analysis is carried out according to the single crack. The specific service working condition stress analysis and calculation process can be realized by adopting the prior art, and the details are not repeated herein.
In some embodiments, the evaluation and calculation of whether the preset crack may generate destabilization and propagation under the current service condition by using a failure assessment graph method according to the analysis result based on fracture mechanics includes:
crack propagation calculations controlled by high temperature creep factors, and crack propagation calculations controlled by thermal fatigue factors.
Preferably, the resetting of the predicted service period shorter than the predicted service period and the evaluation and calculation of whether the new crack after propagation in the predicted service period will generate unstable propagation under the current service condition by using the failure evaluation graph method again include:
after acquiring the characteristic size of a new crack expanded after the predicted service period is ended, evaluating and calculating whether the new crack can be subjected to destabilization expansion under the current service condition by adopting a failure evaluation graph method again; if the analysis result represents that the preset crack can be unstably expanded under the current service condition, the evaluation result of the part to be evaluated is a risk in the expected service period; otherwise, the evaluation result of the component to be evaluated is safety in the expected service period.
If the calculation result shows that the crack can be unstably expanded under the current service condition, the service life evaluation conclusion of the part is unqualified, and the part needs to be repaired or replaced. And if the calculation result is safe, analyzing and calculating the crack propagation condition of the crack in the planned service period by adopting a fracture mechanics method, and evaluating and calculating a new crack with the propagated size and position by adopting a failure assessment map method (FAD). And if the calculation result shows that the new crack can not generate destabilization propagation under the current service condition, the service life evaluation conclusion of the component is safe in the planned service period. If the calculation result is unqualified, the planned service period can be reset, and the crack propagation calculation and the FAD map evaluation are repeatedly carried out.
The present application uses the failure assessment map method (FAD) to assess the above cracks. The FAD graph is a short for Failure access Diagram, and is a safety evaluation method based on double parameters, wherein the first parameter (abscissa) is a plastic instability factor (Lr), the second parameter (ordinate) is a fracture factor (Kr), and a curve in the graph is a cutoff line Lrmax. Wherein the cut-off line is related to the mechanical properties of the material; the two parameters are obtained by calculation according to parameters such as the characteristic size of the crack, the two parameters form a coordinate point in the graph, the coordinate point is located in a region enclosed by a cut-off line and an XY axis, safety is achieved, and danger is achieved when the coordinate point exceeds the cut-off line. The results obtained by the technical scheme provided by the application are shown in fig. 3, which shows that the valve shell can not have sudden instability fracture under the position, size and service condition of the crack. (note: the black dots are located within the range formed by the coordinate axis and the curve in the figure), it is understood that the farther the black dots are from the curve in the figure, the farther the instability fracture occurs, and the closer the black dots are from the curve, the easier the instability fracture occurs.
In some embodiments, the present application calculates and analyzes the propagation of a crack over a 1 ten thousand hour planned service period. Taking into account the crack propagation due to creep and fatigue factors, the calculations show that the buried crack has propagated to the inner surface of the component, as shown in fig. 4.
And calculating and analyzing the new cracks under the service condition by adopting an FAD (false face detection) image method. As a result, as shown in FIG. 5, after the valve body is in service for 1 ten thousand hours, the valve body still has no sudden unstable fracture. However, the evaluation result of the new crack is close to the boundary line, so that a larger safety risk exists, and replacement treatment is recommended.
In some embodiments, the distance between the two ends of the predetermined crack and the inner wall of the part to be evaluated is 10 mm and 20 mm, respectively;
the length of the preset crack is 10 mm;
the distance between the two preset cracks is 10 mm.
As shown in fig. 6, an embodiment of the present application provides an apparatus for evaluating a lifetime of a multi-crack cast steel part after repair, including:
the acquisition module 601 is used for acquiring a stress concentration region of a component to be evaluated and determining a typical position and a characteristic size of a buried crack in the stress concentration region;
the establishing module 602 is configured to establish a finite element model according to a typical position and a characteristic size of a buried crack in the stress concentration region, where at least one preset crack having the same size as the buried crack is set in the finite element model;
and the evaluation module 603 is configured to perform calculation analysis on the stress field of the preset crack in the preset region based on the finite element model, and evaluate the service life of the component to be evaluated according to an analysis result.
The service life evaluation device after repairing the multi-crack cast steel component provided by the embodiment of the application has the working principle that the acquisition module 601 acquires a stress concentration area of the component to be evaluated and determines the typical position and the characteristic size of a buried crack in the stress concentration area; the establishing module 602 establishes a finite element model according to the typical position and the characteristic size of the buried crack in the stress concentration region, and at least one preset crack with the same size as the buried crack is arranged in the finite element model; the evaluation module 603 performs calculation and analysis on the stress field of the preset crack in the preset region based on the finite element model, and evaluates the service life of the component to be evaluated according to the analysis result.
The present application provides a computer device comprising: a memory, which may include volatile memory in a computer readable medium, random Access Memory (RAM), and/or non-volatile memory, such as Read Only Memory (ROM) or flash memory (flash RAM). The computer device stores an operating system, and the memory is an example of a computer-readable medium. The computer program, when executed by the processor, causes the processor to perform a method for life assessment after multi-crack cast steel component repair, the structure shown in fig. 7 is a block diagram of only a portion of the structure associated with the present application, and does not constitute a limitation on the computer apparatus to which the present application is applied, and a specific computer apparatus may include more or less components than those shown in the figure, or combine certain components, or have a different arrangement of components.
In one embodiment, the method for evaluating the service life of the multi-crack cast steel component after repair provided by the application can be realized in the form of a computer program which can be run on a computer device as shown in fig. 7.
In some embodiments, the computer program, when executed by the processor, causes the processor to perform the steps of: acquiring a stress concentration area of a component to be evaluated, and determining a typical position and a characteristic size of a buried crack in the stress concentration area; establishing a finite element model according to the typical position and the characteristic size of the buried crack in the stress concentration region, and arranging at least one preset crack with the same size as the buried crack in the finite element model; and calculating and analyzing the stress field of the preset crack in a preset area based on the finite element model, and evaluating the service life of the part to be evaluated according to the analysis result.
The present application also provides a computer storage medium, examples of which include, but are not limited to, phase change memory (PRAM), static Random Access Memory (SRAM), dynamic Random Access Memory (DRAM), other types of Random Access Memory (RAM), read Only Memory (ROM), electrically Erasable Programmable Read Only Memory (EEPROM), flash memory or other memory technology, compact disc read only memory (CD-ROM), digital Versatile Discs (DVD) or other optical storage, magnetic cassette tape storage or other magnetic storage devices, or any other non-transmission medium, that can be used to store information that can be accessed by a computing device.
In some embodiments, the present invention further provides a computer-readable storage medium storing a computer program, which when executed by a processor, acquires a stress concentration region of a component to be evaluated, and determines a typical position and a characteristic dimension of a buried crack in the stress concentration region; establishing a finite element model according to the typical position and the characteristic size of the buried crack in the stress concentration region, and arranging at least one preset crack with the same size as the buried crack in the finite element model; and calculating and analyzing the stress field of the preset crack in a preset area based on the finite element model, and evaluating the service life of the part to be evaluated according to the analysis result.
In summary, the invention provides a method and a device for evaluating the service life of a repaired multi-crack cast steel component, wherein the method comprises the steps of obtaining a stress concentration area of the component to be evaluated, and determining a typical position and a characteristic dimension of a buried crack in the stress concentration area; establishing a finite element model according to the typical position and the characteristic size of the buried crack in the stress concentration region, and arranging at least one preset crack with the same size as the buried crack in the finite element model; and calculating and analyzing the stress field of the preset crack in the preset area based on the finite element model, and evaluating the service life of the component to be evaluated according to the analysis result. The method can evaluate the service life of the repaired cast steel part, and prevent equipment from cracking in the using process to cause safety problems.
It is to be understood that the embodiments of the method provided above correspond to the embodiments of the apparatus described above, and the corresponding specific contents may be referred to each other, which is not described herein again.
As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, optical storage, and the like) having computer-usable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.
Claims (8)
1. A method for evaluating the service life of a multi-crack cast steel component after repair, comprising:
setting a stress concentration area of a component to be evaluated through a preset finite element model, and setting at least one preset virtual crack with the same size as the characteristic size in the stress concentration area according to the characteristic size of a typical buried crack obtained in the repair process of the component to be evaluated;
calculating and analyzing the stress field of the preset virtual crack in a preset area, and evaluating and calculating whether the preset crack can generate destabilization expansion under the current service condition by adopting a failure evaluation graph method according to the analysis result based on fracture mechanics; if the analysis result represents that the preset crack can be unstably expanded under the current service condition, the evaluation result of the part to be evaluated is dangerous under the current condition; otherwise, the evaluation result of the part to be evaluated is safe under the current condition;
and when the evaluation result of the part to be evaluated is the risk in the expected service period, resetting the expected service period shorter than the expected service period, and evaluating and calculating whether the new crack expanded in the expected service period can be unstably expanded under the current service condition by adopting a failure evaluation graph method again.
2. The method of claim 1, wherein the feature size comprises:
buried depth, length and width.
3. The method according to claim 1, wherein the evaluation calculation of whether the preset crack can generate destabilized propagation under the current service condition by adopting a failure assessment chart method according to the analysis result based on fracture mechanics comprises the following steps:
crack propagation calculations controlled by high temperature creep factors, and crack propagation calculations controlled by thermal fatigue factors.
4. The method according to claim 3, wherein the resetting of the predicted service period shorter than the predicted service period and the evaluation and calculation of whether the new crack after the propagation in the predicted service period will have instability propagation under the current service condition by using the failure evaluation graph method again comprise:
after acquiring the characteristic size of a new crack which is expanded after the end of the expected service period, evaluating and calculating whether the new crack can be unstably expanded or not under the current service condition by adopting a failure evaluation graph method again; if the analysis result indicates that the preset crack can be unstably expanded under the current service condition, the evaluation result of the part to be evaluated is a risk in the expected service period; otherwise, the evaluation result of the part to be evaluated is safety in the expected service period.
5. The method according to any one of claims 1 to 4, characterized in that, when the estimated lifetime of the component to be evaluated is dangerous,
and repairing or replacing the part to be evaluated.
6. An apparatus for evaluating a lifetime of a multi-cracked cast steel member after repair, comprising:
the system comprises a presetting module, a detection module and a control module, wherein the presetting module is used for setting a stress concentration area of a part to be evaluated through a preset finite element model, and setting at least one preset virtual crack with the same characteristic size in the stress concentration area according to the characteristic size of a typical buried crack obtained in the process of repairing the part to be evaluated;
the calculation and analysis module is used for calculating and analyzing the stress field of the preset virtual crack in a preset area, and evaluating and calculating whether the preset virtual crack can be subjected to destabilization expansion under the current service condition by adopting a failure evaluation graph method according to the analysis result based on fracture mechanics; if the analysis result represents that the preset crack can be unstably expanded under the current service condition, the evaluation result of the part to be evaluated is dangerous under the current condition; otherwise, the evaluation result of the part to be evaluated is safe under the current condition;
and the evaluation processing module is used for resetting the predicted service period shorter than the predicted service period when the evaluation result of the part to be evaluated is the risk in the predicted service period, and evaluating and calculating whether the new crack expanded in the predicted service period can be unstably expanded under the current service condition by adopting a failure evaluation graph method again.
7. A computer device, comprising: a memory storing a computer program that, when executed by the processor, causes the processor to execute the method for life assessment after multi-crack cast steel component repair as claimed in any one of claims 1 to 5.
8. A computer storage medium, characterized by storing a computer program which, when executed by a processor, causes the processor to execute the method for life assessment after multi-crack cast steel component repair as claimed in any one of claims 1 to 5.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN117473839A (en) * | 2023-12-26 | 2024-01-30 | 合肥通用机械研究院有限公司 | Calculation method for fatigue life of crack-containing stress concentration part |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN117473839A (en) * | 2023-12-26 | 2024-01-30 | 合肥通用机械研究院有限公司 | Calculation method for fatigue life of crack-containing stress concentration part |
| CN117473839B (en) * | 2023-12-26 | 2024-03-15 | 合肥通用机械研究院有限公司 | Calculation method for fatigue life of crack-containing stress concentration part |
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