Method and device for calculating fracture toughness value of crack tip low alloy steel material

Abstract

The invention provides a method and device for calculating the fracture toughness value of a crack tip low alloy steel material, and relates to the technical field of fracture mechanics. According to the method, the crack depth is assumed in the primary loop pressure-bearing equipment of the nuclear energy system, the ratio of the assumed crack depth to the wall thickness of the equipment is calculated, and whether the assumed crack is a deep crack or a shallow crack is judged according to the calculated ratio; then, according to a constructed calculation model of the fracture toughness of the crack tip low-alloy steel material considering the crack depth and the biaxial load effect, a more reliable and accurate fracture toughness value of the low-alloy steel material can be obtained, and the method can better serve analysis and evaluation of rapid fracture failure resistance of primary loop pressure-bearing equipment of a nuclear energy system. And safe operation of the equipment is protected.

Description

Technical Field

[0001] The present application relates to the technical field of fracture mechanics, and in particular to a method and device for calculating the fracture toughness value of a low alloy steel material at a crack tip. Background Art

[0002] The primary circuit pressure-bearing equipment of the nuclear energy system serves in a harsh environment where pressure (such as high pressure), temperature (such as high temperature), neutron irradiation, etc. coexist. In order to ensure the safe and stable operation of the pressure-bearing equipment during the design life, the designers pay great attention to the structural integrity evaluation of the above pressure-bearing equipment in the design. Among them, the evaluation of preventing the equipment from uncontrollable rapid fracture failure is an important part of the structural integrity evaluation. The primary circuit pressure-bearing equipment of the nuclear energy system mainly includes reactor pressure vessels, steam generators, pressurizers, main pump casings, etc. The above pressure-bearing equipment is often designed with low-alloy steel materials such as 18MND5 steel, 16MND5 steel, 20MND5 steel, SA5083-1 steel, SA5083-2 steel, and SA533B-1 steel. The low-alloy steel here is a steel made by adding a small amount of alloy elements on the basis of carbon steel. These alloy elements include manganese, silicon, vanadium, titanium, aluminum, chromium, nickel, and rare earth elements. The addition of these elements is intended to improve the comprehensive mechanical properties of steel, such as strength, toughness, welding performance, forming performance, and corrosion resistance.

[0003] In the current analysis of pressure-bearing equipment's resistance to rapid fracture failure, it is first necessary to assume that there is a crack defect in the pressure-bearing equipment, and then calculate the stress intensity factor K value of the dangerous area at the crack defect tip through simulation analysis software, and then consider a certain safety factor for the analyzed event or working condition, and finally compare the calculated stress intensity factor K value of the dangerous area at the crack tip with the fracture toughness limit of the crack tip material to determine whether the equipment has an uncontrollable rapid fracture failure risk. The corresponding judgment rule is: if the crack tip stress intensity factor K value after considering a certain safety factor is lower than the fracture toughness limit of the crack tip material, it is determined that the equipment will not fail rapidly; if the crack tip stress intensity factor K value after considering a certain safety factor is higher than the fracture toughness limit of the crack tip material, it is determined that the equipment will fail rapidly. From the above analysis and evaluation process of pressure-bearing equipment's resistance to rapid fracture failure, it can be found that the fracture toughness limit of the low-alloy steel material of pressure-bearing equipment is an important parameter in the fracture failure evaluation. Here, fracture toughness is an indicator that describes the material's ability to resist crack extension. The fracture toughness limit of low-alloy steel material refers to the maximum crack extension capacity that the low-alloy steel material can withstand before being safely used under specific conditions. Exceeding this limit may cause failure or damage to the structure.

[0004] Therefore, how to reliably and accurately calculate the fracture toughness value of low-alloy steel materials at the crack tip, so as to better serve the analysis and evaluation of the resistance to rapid fracture failure of the primary circuit pressure-bearing equipment of the nuclear energy system, has become a technical problem that needs to be solved urgently. Summary of the invention

[0005] In view of the above problems, the present application is proposed to provide a method and device for calculating the fracture toughness value of a low alloy steel material at a crack tip that overcomes the above problems or at least partially solves the above problems. The technical solution is as follows:

[0006] In a first aspect, a method for calculating the fracture toughness value of a low alloy steel material at a crack tip is provided, the method comprising:

[0007] Assuming a crack depth in a primary circuit pressure-bearing equipment of a nuclear energy system, and calculating the ratio of the assumed crack depth to the equipment wall thickness, and determining whether the assumed crack is a deep crack or a shallow crack based on the calculated ratio;

[0008] If it is determined that the assumed crack is a shallow crack, the fracture toughness value of the shallow crack tip low alloy steel material under uniaxial tensile load is calculated according to the pre-constructed fracture toughness calculation model of the deep and shallow crack tips of the low alloy steel material under uniaxial tensile load; and, based on the pre-constructed fracture toughness calculation model of the shallow crack tip low alloy steel material affected by the biaxial factor and the calculated fracture toughness value of the shallow crack tip low alloy steel material under uniaxial tensile load, the fracture toughness value of the shallow crack tip low alloy steel material considering biaxial load is calculated;

[0009] If it is determined that the assumed crack is a deep crack, the fracture toughness value of the deep crack tip low alloy steel material under uniaxial tensile load is calculated according to the pre-constructed fracture toughness calculation model of the low alloy steel material at the tips of deep and shallow cracks under uniaxial tensile load; and, based on the pre-constructed fracture toughness calculation model of the deep crack tip low alloy steel material affected by the biaxial factor and the calculated fracture toughness value of the deep crack tip low alloy steel material under uniaxial tensile load, the fracture toughness value of the deep crack tip low alloy steel material considering the biaxial load is calculated.

[0010] In a second aspect, a device for calculating the fracture toughness value of a low alloy steel material at a crack tip is provided, the device comprising:

[0011] A determination unit, used for assuming a crack depth in a primary circuit pressure-bearing device of a nuclear energy system, calculating a ratio of the assumed crack depth to the device wall thickness, and determining whether the assumed crack is a deep crack or a shallow crack according to the calculated ratio;

[0012] A first calculation unit is used to calculate the fracture toughness value of the shallow crack tip low alloy steel material under uniaxial tensile load according to a pre-constructed fracture toughness calculation model of the deep and shallow crack tip low alloy steel material under uniaxial tensile load if it is determined that the assumed crack is a shallow crack; and to calculate the fracture toughness value of the shallow crack tip low alloy steel material considering biaxial load based on a pre-constructed fracture toughness calculation model of the shallow crack tip low alloy steel material affected by a biaxial factor and the calculated fracture toughness value of the shallow crack tip low alloy steel material under uniaxial tensile load;

[0013] The second calculation unit is used to calculate the fracture toughness value of the deep crack tip low alloy steel material under uniaxial tensile load according to a pre-constructed fracture toughness calculation model of the low alloy steel material at the deep and shallow crack tips under uniaxial tensile load if it is determined that the assumed crack is a deep crack; and to calculate the fracture toughness value of the deep crack tip low alloy steel material considering biaxial load based on a pre-constructed fracture toughness calculation model of the deep crack tip low alloy steel material affected by the biaxial factor and the calculated fracture toughness value of the deep crack tip low alloy steel material under uniaxial tensile load.

[0014] In a third aspect, an electronic device is provided, comprising a processor and a memory, wherein the memory stores a computer program, and the processor is configured to run the computer program to execute any of the above-mentioned methods for calculating the fracture toughness value of the low alloy steel material at the crack tip.

[0015] In a fourth aspect, a storage medium is provided, wherein the storage medium stores a computer program, wherein the computer program is configured to execute any of the above-mentioned methods for calculating the fracture toughness value of a low-alloy steel material at a crack tip when running.

[0016] In a fifth aspect, a computer program product is provided, comprising a computer program, wherein the computer program is configured to execute any of the above-mentioned methods for calculating the fracture toughness value of a low alloy steel material at a crack tip when running.

[0017] By means of the above technical scheme, the embodiments of the present application provide a method and device for calculating the fracture toughness value of a low-alloy steel material at a crack tip, an electronic device and a storage medium. The method assumes a crack depth in a pressure-bearing device of a nuclear energy system primary circuit, and calculates the ratio of the assumed crack depth to the wall thickness of the equipment, and determines whether the assumed crack is a deep crack or a shallow crack according to the calculated ratio; then, calculations are carried out according to a pre-constructed fracture toughness calculation model for low-alloy steel materials at the deep and shallow crack tips under a uniaxial tensile load, and the constructed fracture toughness calculation model for low-alloy steel materials at the deep and shallow crack tips under a uniaxial tensile load takes into account the influence of the crack depth size on the fracture toughness of the low-alloy steel material at the crack tip; and then, based on the pre-constructed fracture toughness calculation model for low-alloy steel materials at the shallow crack tip affected by a biaxial factor and the calculated fracture toughness value of the low-alloy steel materials at the shallow crack tip under a uniaxial tensile load, the fracture toughness value of the low-alloy steel material at the shallow crack tip considering the biaxial load is calculated, and based on the pre-constructed fracture toughness calculation model for low-alloy steel materials at the shallow crack tip affected by a biaxial factor and the calculated fracture toughness value of the low-alloy steel materials at the shallow crack tip under a uniaxial tensile load, the fracture toughness value of the low-alloy steel material at the shallow crack tip considering the biaxial load is calculated. First, a calculation model for the fracture toughness of low-alloy steel materials at the deep crack tip affected by the biaxial factor and the calculated fracture toughness value of the low-alloy steel materials at the deep crack tip under uniaxial tensile load are constructed, and then the fracture toughness value of the low-alloy steel materials at the deep crack tip considering the biaxial load is calculated. It can be seen that the calculation model for the fracture toughness of low-alloy steel materials at the shallow crack tip affected by the biaxial factor and the calculation model for the fracture toughness of low-alloy steel materials at the deep crack tip affected by the biaxial factor constructed in this embodiment take into account the influence of the biaxial load effect on the fracture toughness of the low-alloy steel materials at the crack tip; thereby obtaining the fracture toughness value of the low-alloy steel materials considering the crack depth and biaxial load effect, that is, the fracture toughness value of the low-alloy steel materials at the shallow crack tip considering the biaxial load or the fracture toughness value of the low-alloy steel materials at the deep crack tip considering the biaxial load, which is more reliable and accurate, can better serve the analysis and evaluation of the resistance to rapid fracture failure of the primary circuit pressure-bearing equipment of the nuclear energy system, and escort the safe operation of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in describing the embodiments of the present application are briefly introduced below.

[0019] Figure 1 A flow chart showing a method for calculating the fracture toughness value of a low alloy steel material at a crack tip provided in an embodiment of the present application is shown;

[0020] Figure 2 A structural diagram of a device for calculating the fracture toughness value of a low alloy steel material at a crack tip provided in an embodiment of the present application is shown;

[0021] Figure 3 A structural diagram of an electronic device provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0022] The exemplary embodiments of the present application will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present application are shown in the accompanying drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present application and to fully convey the scope of the present application to those skilled in the art.

[0023] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that such use is interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the term "including" and its variants are to be interpreted as open-ended terms meaning "including but not limited to".

[0024] In order to solve the above technical problems, the present application embodiment provides a method for calculating the fracture toughness value of a low alloy steel material at a crack tip, such as Figure 1 As shown, the method for calculating the fracture toughness value of the low alloy steel material at the crack tip may include the following steps S101 to S103:

[0025] Step S101, assuming a crack depth in a primary circuit pressure-bearing device of a nuclear energy system, and calculating a ratio of the assumed crack depth to the device wall thickness, and determining whether the assumed crack is a deep crack or a shallow crack according to the calculated ratio;

[0026] Step S102, if it is determined that the assumed crack is a shallow crack, then according to the pre-constructed fracture toughness calculation model of the low-alloy steel material at the tip of a deep and shallow crack under a uniaxial tensile load, the fracture toughness value of the low-alloy steel material at the tip of a shallow crack under a uniaxial tensile load is calculated; and, based on the pre-constructed fracture toughness calculation model of the low-alloy steel material at the tip of a shallow crack affected by a biaxial factor and the calculated fracture toughness value of the low-alloy steel material at the tip of a shallow crack under a uniaxial tensile load, the fracture toughness value of the low-alloy steel material at the tip of a shallow crack considering a biaxial load is calculated;

[0027] Step S103, if it is determined that the assumed crack is a deep crack, then according to the pre-constructed fracture toughness calculation model of the low alloy steel material at the deep and shallow crack tips under uniaxial tensile load, the fracture toughness value of the deep crack tip low alloy steel material is calculated; and, based on the pre-constructed fracture toughness calculation model of the deep crack tip low alloy steel material affected by the biaxial factor and the calculated fracture toughness value of the deep crack tip low alloy steel material under uniaxial tensile load, the fracture toughness value of the deep crack tip low alloy steel material considering the biaxial load is calculated.

[0028] In this embodiment, a crack depth is assumed in the primary-loop pressure-bearing equipment of the nuclear energy system, and the ratio of the assumed crack depth to the wall thickness of the equipment is calculated, and whether the assumed crack is a deep crack or a shallow crack is determined according to the calculated ratio; then, calculations are carried out according to a pre-constructed fracture toughness calculation model for low-alloy steel materials at the tips of deep and shallow cracks under uniaxial tensile loads, and the constructed fracture toughness calculation model for low-alloy steel materials at the tips of deep and shallow cracks under uniaxial tensile loads takes into account the influence of the crack depth size on the fracture toughness of the low-alloy steel materials at the crack tip; and then, based on the pre-constructed fracture toughness calculation model for low-alloy steel materials at the tips of shallow cracks affected by biaxial factors and the calculated fracture toughness value of low-alloy steel materials at the tips of shallow cracks under uniaxial tensile loads, the fracture toughness value of the low-alloy steel materials at the tips of shallow cracks considering biaxial loads is calculated, as well as the fracture toughness value of the low-alloy steel materials at the tips of deep cracks affected by biaxial factors based on the pre-constructed fracture toughness calculation model for low-alloy steel materials at the tips of deep cracks under The toughness calculation model and the calculated fracture toughness value of the deep crack tip low alloy steel material under uniaxial tensile load, and the fracture toughness value of the deep crack tip low alloy steel material considering biaxial load are calculated. It can be seen that the fracture toughness calculation model of the shallow crack tip low alloy steel material affected by the biaxial factor and the fracture toughness calculation model of the deep crack tip low alloy steel material affected by the biaxial factor constructed in this embodiment take into account the influence of the biaxial load effect on the fracture toughness of the crack tip low alloy steel material; the fracture toughness value of the low alloy steel material considering the crack depth and biaxial load effect, that is, the fracture toughness value of the shallow crack tip low alloy steel material considering the biaxial load or the fracture toughness value of the deep crack tip low alloy steel material considering the biaxial load, are more reliable and accurate, and can better serve the analysis and evaluation of the resistance to rapid fracture failure of the primary circuit pressure-bearing equipment of the nuclear energy system, and escort the safe operation of the equipment.

[0029] In the above embodiment, in terms of the assumed crack depth of the pressure-bearing equipment, it is assumed that the crack depth a is related to the equipment wall thickness t. The provisions on the crack depth a in RCC-M (2017 edition) are:

[0030]

[0031] Among them, a is the crack depth, in mm (millimeter), and t is the equipment wall thickness, in mm. Since the material fracture toughness limit at the tip of a shallow crack is higher than the material fracture toughness limit at the tip of a deep crack, deep cracks and shallow cracks will affect the calculation results of the fracture toughness limit of low alloy steel materials. However, RCC-M (2017 edition) does not provide a judgment rule for deep cracks and shallow cracks. The RCC-M here is a series of specifications formulated by the Association for the Design, Construction and In-Service Inspection of Nuclear Island Components.

[0032] The present application provides a possible implementation method. In the above step S101, the ratio of the assumed crack depth to the equipment wall thickness is calculated. According to the calculated ratio, whether the assumed crack is a deep crack or a shallow crack is determined. Specifically, the following steps A1 to A3 may be included:

[0033] Step A1, calculating the ratio of the assumed crack depth to the equipment wall thickness;

[0034] Step A2, if the calculated ratio is greater than the set ratio, the assumed crack is a deep crack;

[0035] In step A3, if the calculated ratio is less than or equal to the set ratio, the assumed crack is a shallow crack.

[0036] In this embodiment, the ratio can be set according to actual needs, for example, the ratio can be set to 20% or 0.2, which is not limited in this embodiment.

[0037] In terms of the calculation model of the fracture toughness limit of low alloy steel materials, the fracture toughness limit is related to the crack tip temperature T and the ductile-brittle transition temperature RT of the material. NDT Related, RCC-M (2017 edition) is used to calculate the fracture toughness limit of low alloy steel materials at the deep crack tip as follows:

[0038]

[0039] Its applicable temperature range is -100℃≤T-RT NDT ≤60℃, T is the crack tip temperature, unit is ℃; RT NDT RT is the ductile-brittle transition temperature of low alloy steel, in °C. NDT Affected by multiple factors such as neutron irradiation, thermal aging, strain aging, etc. is the fracture toughness value of low alloy steel material at the deep crack tip, in MPa·m 1 / 2 The model can be obtained by analyzing the fracture toughness test data of laboratory uniaxial tensile specimens such as compact tensile specimens. However, in the process of transforming laboratory test data into engineering design applications, on the one hand, the model does not consider the influence of the ratio of crack depth to equipment wall thickness, i.e. a / t, on the fracture toughness limit of the material; on the other hand, the model does not consider the influence of the biaxial load generated by the service environment of the pressure equipment on the fracture toughness limit of the material.

[0040] From the above explanation, it can be seen that in engineering design applications, it is necessary to consider the ratio of the assumed crack depth size to the equipment wall thickness and the influence of the biaxial load of the pressure equipment in service in the fracture toughness limit calculation model of low alloy steel materials, so as to obtain a more reliable fracture toughness calculation model of low alloy steel materials, and then better serve the analysis and evaluation of the resistance to rapid fracture failure of the primary circuit pressure equipment of the nuclear energy system to ensure the safety of the equipment.

[0041] The embodiment of the present application introduces the influence of factors such as crack depth and biaxial load of pressure equipment on the fracture calculation model of low alloy steel materials at different temperatures, thereby establishing a low alloy steel fracture toughness model that takes into account the effects of crack depth and biaxial load; based on the established model, the resistance to rapid fracture failure of the primary circuit pressure equipment of the nuclear energy system can be analyzed and evaluated to ensure the safe operation of the equipment.

[0042] Specifically, the pre-built fracture toughness calculation model of low alloy steel material at the tip of deep or shallow crack under uniaxial tensile load mentioned in step S102 or step S103 above is as follows:

[0043]

[0044]

[0045] Among them, when the crack is a deep crack, F modi =1.0, is the fracture toughness value of low alloy steel material at the deep crack tip under uniaxial tensile load;

[0046] When the crack is a shallow crack,

[0047]

[0048] is the fracture toughness value of low alloy steel material at the shallow crack tip under uniaxial tensile load;

[0049] is the fracture toughness value of low alloy steel material at the deep crack tip, in MPa·m 1 / 2 ; T is the crack tip temperature, in °C; RT NDT is the ductile-brittle transition temperature of low alloy steel material, in °C; a is the crack depth, in mm; σ Y It is the yield stress strength of low alloy steel material that changes with temperature at the crack tip, in MPa.

[0050] In this embodiment, calculations are carried out based on a pre-constructed fracture toughness calculation model for low alloy steel materials at deep and shallow crack tips under uniaxial tensile loads. The constructed fracture toughness calculation model for low alloy steel materials at deep and shallow crack tips under uniaxial tensile loads takes into account the influence of crack depth on the fracture toughness of low alloy steel materials at crack tips.

[0051] A possible implementation method is provided in the embodiment of the present application. The pre-built fracture toughness calculation model of the low alloy steel material at the shallow crack tip affected by the biaxial factor mentioned in step S102 is as follows:

[0052]

[0053]

[0054] in, is the fracture toughness value of low alloy steel material at the shallow crack tip considering biaxial loading; biax is the influence coefficient of biaxial load; β biax is the biaxial factor, specifically the ratio of the stress component along the crack surface to the stress component normal to the crack surface.

[0055] A possible implementation method is provided in the embodiment of the present application. The pre-built fracture toughness calculation model of the low alloy steel material at the deep crack tip affected by the biaxial factor mentioned in step S103 above is as follows:

[0056]

[0057] in, is the fracture toughness value of low alloy steel material at the deep crack tip considering biaxial loading.

[0058] It can be seen that this embodiment provides a calculation method and model for the fracture toughness of low alloy steel materials taking into account the crack depth and biaxial load effects. Through the provided calculation method, when the crack tip temperature and the ductile-brittle transition temperature of the low alloy steel material are known, combined with the assumed crack depth, equipment wall thickness, yield stress strength of the low alloy steel material at the crack tip, and biaxial factor, a low alloy steel fracture toughness model taking into account the crack depth and biaxial load effects is established. Based on the established model, a more reliable fracture toughness value of the low alloy steel material can be obtained, which can better serve the analysis and evaluation of the resistance to rapid fracture failure of the primary circuit pressure equipment of the nuclear energy system, and safeguard the safe operation of the equipment.

[0059] The above introduces Figure 1 There are various implementation methods for each link of the illustrated embodiment. The calculation method of the fracture toughness value of the low alloy steel material at the crack tip of the embodiment of the present application will be further explained below through specific examples.

[0060] In a specific embodiment, the known parameters are the crack tip temperature T, the ductile-brittle transition temperature RT of the low alloy steel material. NDT .

[0061] Specifically, the crack tip temperature T = 35 ° C, the ductile-brittle transition temperature RT of low alloy steel material 16MND5 NDT =-20°C. Assuming the wall thickness of the pressure equipment is t = 200mm, the assumed crack depth according to RCC-M (2017 edition) is a = 20mm.

[0062] The detailed implementation process is as follows:

[0063] 1.1) Entering step S101, and specifically determining whether the assumed crack is a deep crack or a shallow crack according to steps A1 to A3;

[0064] The calculated value is a / t=20mm / 200mm=0.1, which is less than the set ratio of 0.2, and the crack is determined to be a shallow crack;

[0065] 1.2) Enter step S102, take the yield stress strength of the low alloy steel material at 35°C as σ Y =340MPa;

[0066] Calculated n=0.138,f modi =3.0, and then we get Here is the fracture toughness value of low alloy steel material at the shallow crack tip under uniaxial tensile load;

[0067] Furthermore, taking the biaxial factor β biax = 0.5, we get w biax =0.9;

[0068] So we can calculate

[0069] In another specific embodiment, the known parameters are the crack tip temperature T, the ductile-brittle transition temperature RT of the low alloy steel material NDT .

[0070] Specifically, the crack tip temperature T = 35 ° C, the ductile-brittle transition temperature RT of low alloy steel material 16MND5 NDT = -20°C. Assume that the wall thickness of the pressure-bearing equipment is t = 200 mm and the assumed crack depth is a = 50 mm.

[0071] The detailed implementation process is as follows:

[0072] 2.1) Entering step S101, and specifically determining whether the assumed crack is a deep crack or a shallow crack according to steps A1 to A3;

[0073] The calculated value a / t=50mm / 200mm=0.25 is greater than the set ratio 0.2, and the crack is determined to be a deep crack;

[0074] 2.2) Enter step S103 and calculate F modi =1.0, and then we get Here is the fracture toughness value of low alloy steel material at the deep crack tip under uniaxial tensile load;

[0075] Further, we calculate

[0076] In the above specific embodiment, a calculation model for the fracture toughness value of low alloy steel materials at the crack tip considering the crack depth and biaxial load effect is provided. The analysis process is: first, the crack depth is assumed in the primary pressure-bearing equipment of the nuclear energy system, and the ratio of the assumed crack depth to the equipment wall thickness is calculated, and the assumed crack is determined to be a deep crack or a shallow crack according to the ratio; second, the calculation is carried out according to the fracture toughness calculation model of the low alloy steel materials at the deep and shallow crack tips under the constructed uniaxial tensile load; third, if the assumed crack defect is a shallow crack, the influence of the biaxial factor on the calculation result of the fracture toughness of the crack tip needs to be further considered; if the assumed crack defect is a deep crack, there is no need to further consider the influence of the biaxial factor on the calculation result of the fracture toughness of the crack tip. It can be seen that the model established in this embodiment takes into account the ratio of the assumed crack size to the equipment wall thickness and the influence of the biaxial loading of the pressure-bearing equipment, and a more reliable fracture toughness calculation model of low alloy steel materials can be obtained, which can better serve the analysis and evaluation of the resistance to rapid fracture failure of the primary pressure-bearing equipment of the nuclear energy system, and escort the safe operation of the equipment.

[0077] It should be noted that the size of the sequence number of each step in the above embodiment does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present application. In practical applications, all the above possible implementation methods can be combined in any way to form possible embodiments of the present application, which will not be described one by one here.

[0078] Based on the calculation method of the fracture toughness value of the low alloy steel material at the crack tip provided in each of the above embodiments, based on the same inventive concept, the embodiment of the present application also provides a calculation device for the fracture toughness value of the low alloy steel material at the crack tip.

[0079] Figure 2 1 is a structural diagram of a device for calculating the fracture toughness value of a low alloy steel material at a crack tip provided in an embodiment of the present application. Figure 2As shown, the calculation device for the fracture toughness value of the crack tip low alloy steel material may specifically include a determination unit 210 , a first calculation unit 220 and a second calculation unit 230 .

[0080] The determination unit 210 is used to assume a crack depth in the primary circuit pressure-bearing equipment of the nuclear energy system, calculate the ratio of the assumed crack depth to the equipment wall thickness, and determine whether the assumed crack is a deep crack or a shallow crack according to the calculated ratio;

[0081] The first calculation unit 220 is used to calculate the fracture toughness value of the shallow crack tip low alloy steel material under uniaxial tensile load according to the pre-constructed fracture toughness calculation model of the deep and shallow crack tip low alloy steel material under uniaxial tensile load if it is determined that the assumed crack is a shallow crack; and to calculate the fracture toughness value of the shallow crack tip low alloy steel material considering biaxial load based on the pre-constructed fracture toughness calculation model of the shallow crack tip low alloy steel material affected by the biaxial factor and the calculated fracture toughness value of the shallow crack tip low alloy steel material under uniaxial tensile load;

[0082] The second calculation unit 230 is used to calculate the fracture toughness value of the deep crack tip low alloy steel material under uniaxial tensile load according to a pre-constructed fracture toughness calculation model of the low alloy steel material at the deep and shallow crack tips under uniaxial tensile load if it is determined that the assumed crack is a deep crack; and to calculate the fracture toughness value of the deep crack tip low alloy steel material considering biaxial load based on a pre-constructed fracture toughness calculation model of the deep crack tip low alloy steel material affected by the biaxial factor and the calculated fracture toughness value of the deep crack tip low alloy steel material under uniaxial tensile load.

[0083] A possible implementation manner is provided in an embodiment of the present application, wherein the determining unit 210 is further configured to:

[0084] Calculate the ratio of the assumed crack depth to the equipment wall thickness;

[0085] If the calculated ratio is greater than the set ratio, the assumed crack is a deep crack;

[0086] If the calculated ratio is less than or equal to the set ratio, the assumed crack is a shallow crack.

[0087] A possible implementation method is provided in the embodiment of the present application. The pre-constructed fracture toughness calculation model of low alloy steel material at the tip of deep and shallow cracks under uniaxial tensile load is as follows:

[0088]

[0089]

[0090] Among them, when the crack is a deep crack, F modi =1.0, is the fracture toughness value of low alloy steel material at the deep crack tip under uniaxial tensile load;

[0091] When the crack is a shallow crack,

[0092]

[0093] is the fracture toughness value of low alloy steel material at the shallow crack tip under uniaxial tensile load;

[0094] is the fracture toughness value of low alloy steel material at the deep crack tip, in MPa·m 1 / 2 ; T is the crack tip temperature, in °C; RT NDT is the ductile-brittle transition temperature of low alloy steel material, in °C; a is the crack depth, in mm; σ Y It is the yield stress strength of low alloy steel material that changes with temperature at the crack tip, in MPa.

[0095] A possible implementation method is provided in the embodiment of the present application. The pre-built fracture toughness calculation model of low alloy steel material at the shallow crack tip affected by the biaxial factor is as follows:

[0096]

[0097]

[0098] in, is the fracture toughness value of low alloy steel material at the shallow crack tip considering biaxial loading; biax is the influence coefficient of biaxial load; β biax is the biaxial factor, specifically the ratio of the stress component along the crack surface to the stress component normal to the crack surface.

[0099] A possible implementation method is provided in the embodiment of the present application. The pre-built fracture toughness calculation model of low alloy steel material at the deep crack tip affected by the biaxial factor is as follows:

[0100]

[0101] in, is the fracture toughness value of low alloy steel material at the deep crack tip considering biaxial loading.

[0102] Based on the same inventive concept, an embodiment of the present application also provides an electronic device, including a processor and a memory, wherein a computer program is stored in the memory, and the processor is configured to run the computer program to execute the method for calculating the fracture toughness value of the low alloy steel material at the crack tip of any of the above embodiments.

[0103] In an exemplary embodiment, an electronic device is provided, such as Figure 3 As shown, Figure 3 The electronic device 300 shown includes: a processor 301 and a memory 303. The processor 301 and the memory 303 are connected, such as through a bus 302. Optionally, the electronic device 300 may also include a transceiver 304. It should be noted that in actual applications, the transceiver 304 is not limited to one, and the structure of the electronic device 300 does not constitute a limitation on the embodiments of the present application.

[0104] Processor 301 may be a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array) or other programmable logic devices, transistor logic devices, hardware components or any combination thereof. It may implement or execute various exemplary logic blocks, modules and circuits described in conjunction with the disclosure of this application. Processor 301 may also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of a DSP and a microprocessor, etc.

[0105] The bus 302 may include a path to transmit information between the above components. The bus 302 may be a PCI (Peripheral Component Interconnect) bus or an EISA (Extended Industry Standard Architecture) bus. The bus 302 may be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 3 Only one thick line is used in the diagram, but this does not mean that there is only one bus or only one type of bus.

[0106] The memory 303 can be a ROM (Read Only Memory) or other types of static storage devices that can store static information and instructions, a RAM (Random Access Memory) or other types of dynamic storage devices that can store information and instructions, or an EEPROM (Electrically Erasable Programmable Read Only Memory), a CD-ROM (Compact Disc Read Only Memory) or other optical disk storage, optical disk storage (including compressed optical disk, laser disk, optical disk, digital versatile disk, Blu-ray disk, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store the desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited to these.

[0107] The memory 303 is used to store the computer program code for executing the solution of the present application, and the execution is controlled by the processor 301. The processor 301 is used to execute the computer program code stored in the memory 303 to implement the contents shown in the above method embodiment.

[0108] Among them, electronic devices include but are not limited to: mobile terminals such as mobile phones, laptops, digital broadcast receivers, PDAs (personal digital assistants), PADs (tablet computers), PMPs (portable multimedia players), vehicle-mounted terminals (such as vehicle-mounted navigation terminals), etc., and fixed terminals such as digital TVs, desktop computers, etc. Figure 3 The electronic device shown is merely an example and should not bring any limitation to the functions and scope of use of the embodiments of the present application.

[0109] Based on the same inventive concept, an embodiment of the present application further provides a storage medium, in which a computer program is stored, wherein the computer program is configured to execute a method for calculating the fracture toughness value of a low alloy steel material at a crack tip of any of the above embodiments when running.

[0110] Based on the same inventive concept, an embodiment of the present application also provides a computer program product, including a computer program, wherein the computer program is configured to execute the method for calculating the fracture toughness value of the low alloy steel material at the crack tip of any of the above embodiments when running.

[0111] Those skilled in the art can clearly understand that the specific working processes of the systems, devices, and modules described above can refer to the corresponding processes in the aforementioned method embodiments, and for the sake of brevity, they are not further described here.

[0112] Those skilled in the art can understand that the technical solution of the present application can be essentially or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, which includes a number of program instructions, so that an electronic device (such as a personal computer, a server, or a network device, etc.) executes all or part of the steps of the method described in each embodiment of the present application when running the program instructions. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), disk or optical disk, etc., various media that can store program codes.

[0113] Alternatively, all or part of the steps of implementing the aforementioned method embodiments may be accomplished by hardware associated with program instructions (such as electronic devices such as personal computers, servers, or network devices), and the program instructions may be stored in a computer-readable storage medium. When the program instructions are executed by a processor of an electronic device, the electronic device executes all or part of the steps of the methods described in the embodiments of the present application.

[0114] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that within the spirit and principles of the present application, they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not deviate from the protection scope of the present application.

Claims

1. A method for calculating the fracture toughness value of a low alloy steel material at a crack tip, characterized in that: The method comprises: Assuming a crack depth in a primary circuit pressure-bearing equipment of a nuclear energy system, and calculating the ratio of the assumed crack depth to the equipment wall thickness, and determining whether the assumed crack is a deep crack or a shallow crack based on the calculated ratio; If it is determined that the assumed crack is a shallow crack, the fracture toughness value of the shallow crack tip low alloy steel material under uniaxial tensile load is calculated according to the pre-constructed fracture toughness calculation model of the deep and shallow crack tips of the low alloy steel material under uniaxial tensile load; and, based on the pre-constructed fracture toughness calculation model of the shallow crack tip low alloy steel material affected by the biaxial factor and the calculated fracture toughness value of the shallow crack tip low alloy steel material under uniaxial tensile load, the fracture toughness value of the shallow crack tip low alloy steel material considering biaxial load is calculated; If it is determined that the assumed crack is a deep crack, the fracture toughness value of the deep crack tip low alloy steel material under uniaxial tensile load is calculated according to the pre-constructed fracture toughness calculation model of the low alloy steel material at the tips of deep and shallow cracks under uniaxial tensile load; and, based on the pre-constructed fracture toughness calculation model of the deep crack tip low alloy steel material affected by the biaxial factor and the calculated fracture toughness value of the deep crack tip low alloy steel material under uniaxial tensile load, the fracture toughness value of the deep crack tip low alloy steel material considering the biaxial load is calculated.

2. The method according to claim 1, characterized in that Calculate the ratio of the assumed crack depth to the equipment wall thickness, and determine whether the assumed crack is a deep crack or a shallow crack based on the calculated ratio, including: Calculate the ratio of the assumed crack depth to the equipment wall thickness; If the calculated ratio is greater than the set ratio, the assumed crack is a deep crack; If the calculated ratio is less than or equal to the set ratio, the assumed crack is a shallow crack.

3. The method according to claim 1 or 2, characterized in that: The pre-built fracture toughness calculation model for low alloy steel materials at the tip of deep and shallow cracks under uniaxial tensile load is as follows: Among them, when the crack is a deep crack, F modi =1.0, is the fracture toughness value of low alloy steel material at the deep crack tip under uniaxial tensile load; When the crack is a shallow crack, is the fracture toughness value of low alloy steel material at the shallow crack tip under uniaxial tensile load; is the fracture toughness value of low alloy steel material at the deep crack tip, in MPa·m 1 / 2 ; T is the crack tip temperature, in °C; RT NDT is the ductile-brittle transition temperature of low alloy steel material, in °C; a is the crack depth, in mm; σ Y It is the yield stress strength of low alloy steel material that changes with temperature at the crack tip, in MPa.

4. The method according to claim 3, characterized in that The pre-built fracture toughness calculation model for low alloy steel materials at the shallow crack tip affected by the biaxial factor is as follows: in, is the fracture toughness value of low alloy steel material at the shallow crack tip considering biaxial loading; biax is the influence coefficient of biaxial load; β biax is the biaxial factor, specifically the ratio of the stress component along the crack surface to the stress component normal to the crack surface.

5. The method according to claim 3, characterized in that: The pre-built fracture toughness calculation model for low alloy steel materials at the deep crack tip affected by the biaxial factor is as follows: in, is the fracture toughness value of low alloy steel material at the deep crack tip considering biaxial loading.

6. A device for calculating the fracture toughness value of a low alloy steel material at a crack tip, characterized in that: The device comprises: A determination unit, used for assuming a crack depth in a primary circuit pressure-bearing device of a nuclear energy system, calculating a ratio of the assumed crack depth to the device wall thickness, and determining whether the assumed crack is a deep crack or a shallow crack according to the calculated ratio; A first calculation unit is used to calculate the fracture toughness value of the shallow crack tip low alloy steel material under uniaxial tensile load according to a pre-constructed fracture toughness calculation model of the deep and shallow crack tip low alloy steel material under uniaxial tensile load if it is determined that the assumed crack is a shallow crack; and to calculate the fracture toughness value of the shallow crack tip low alloy steel material considering biaxial load based on a pre-constructed fracture toughness calculation model of the shallow crack tip low alloy steel material affected by a biaxial factor and the calculated fracture toughness value of the shallow crack tip low alloy steel material under uniaxial tensile load; The second calculation unit is used to calculate the fracture toughness value of the deep crack tip low alloy steel material under uniaxial tensile load according to a pre-constructed fracture toughness calculation model of the low alloy steel material at the deep and shallow crack tips under uniaxial tensile load if it is determined that the assumed crack is a deep crack; and to calculate the fracture toughness value of the deep crack tip low alloy steel material considering biaxial load based on a pre-constructed fracture toughness calculation model of the deep crack tip low alloy steel material affected by the biaxial factor and the calculated fracture toughness value of the deep crack tip low alloy steel material under uniaxial tensile load.

7. The device according to claim 6, characterized in that The determination unit is also used for: Calculate the ratio of the assumed crack depth to the equipment wall thickness; If the calculated ratio is greater than the set ratio, the assumed crack is a deep crack; If the calculated ratio is less than or equal to the set ratio, the assumed crack is a shallow crack.

8. An electronic device, characterized in that: The method comprises a processor and a memory, wherein a computer program is stored in the memory, and the processor is configured to run the computer program to execute the method for calculating the fracture toughness value of the crack tip low alloy steel material according to any one of claims 1 to 5.

9. A storage medium, characterized in that: The storage medium stores a computer program, wherein the computer program is configured to execute the method for calculating the fracture toughness value of the crack tip low alloy steel material according to any one of claims 1 to 5 when running.

10. A computer program product, comprising a computer program, characterized in that The computer program is configured to execute the method for calculating the fracture toughness value of a crack tip low alloy steel material according to any one of claims 1 to 5 when running.

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