Method, system, medium, and apparatus for determining fracture toughness of a metal material of a pipe

Abstract

The present application belongs to the field of metal testing, and particularly relates to a method, system, medium and equipment for determining the fracture toughness of a metal material of a pipeline. The method comprises: determining a size parameter of a material to be detected, cutting the material to be detected to obtain a fractured material to be detected, performing a fracture test on the fractured material to be detected based on an unloading compliance program to obtain test results at different times, the material to be detected being a metal material of a pipeline; determining an instantaneous rotation radius at a time based on the size parameter and the test results at the time, determining a plastic zone projection area at the time according to the instantaneous rotation radius at the time; and determining the fracture toughness of the material to be detected at the time based on the size parameter and the plastic zone projection area at the time. The fracture toughness characterization is more accurate, the method adopts a standard fracture test, and the operation is simple. The method also has good applicability to incomplete tests or tests with missing experimental data.

Description

Technical Field

[0001] This invention belongs to the field of metal testing, and particularly relates to methods, systems, media and equipment for determining the fracture toughness of metallic materials in pipelines. Background Technology

[0002] Currently, metals remain irreplaceable engineering materials in many fields such as aerospace, petroleum, and chemical engineering. However, despite their widespread use, metal components exhibit various failure modes, including fracture, corrosion, wear, and deformation. Fracture is the most dangerous failure mode for metal components, often resulting in catastrophic consequences. Therefore, in order to further reduce resource consumption, promote economic growth, and ensure national safety, finding an accurate and reliable method for assessing the fracture risk of metal materials is becoming increasingly important.

[0003] Currently, fracture toughness is widely accepted as a metric for the fracture properties of metallic materials. The traditional method for obtaining fracture toughness involves first conducting standard fracture tests, and then calculating the fracture toughness using empirical formulas based on the recommendations in GB / T 21143-2014, "Unified Test Method for Quasi-Static Fracture Toughness of Metallic Materials." However, relying solely on experience is not applicable to all metallic materials and ignores the heterogeneity and microscopic defects of materials under real-world conditions. Therefore, existing standard tests are insufficient to reflect the true impact of these factors on fracture toughness. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method, system, medium and equipment for determining the fracture toughness of metallic materials for pipelines.

[0005] The technical solution of this invention to solve the above-mentioned technical problems is as follows: A method for determining the fracture toughness of a metallic material for a pipeline, comprising:

[0006] The dimensional parameters of the material to be tested are determined, the material to be tested is cut open to obtain the fractured material to be tested, and a fracture test is performed on the fractured material to be tested based on the unloading compliance program to obtain the test results at different times. The material to be tested is the metal material of the pipe.

[0007] Based on the dimensional parameters and the test results at any given moment, determine the instantaneous radius of rotation at that moment, and then determine the projected area of ​​the plastic zone at that moment based on the instantaneous radius of rotation at that moment.

[0008] The fracture toughness of the material under test at that moment is determined based on the dimensional parameters and the projected area of ​​the plastic zone at that moment.

[0009] The beneficial effects of this invention are: This invention calculates fracture toughness using actual experimental fracture surfaces, which is more consistent with real-world conditions compared to empirical formulas, resulting in more accurate fracture toughness characterization. The method employs standard fracture tests and is simple to operate. Furthermore, this method can calculate fracture toughness JIC using only partial experimental data, making it well-suited for tests with missing or incomplete data. Therefore, it can serve as a method for determining the fracture toughness of components in engineering applications where data is lacking.

[0010] Based on the above technical solution, the present invention can be further improved as follows.

[0011] Furthermore, the instantaneous radius of rotation at that moment is calculated using a first formula, which is:

[0012]

[0013] Among them, R i Let V be the instantaneous rotation radius at time i. 1i V represents the extensometer displacement of the fractured material under test at time i, as described in the experimental results. 2i Let be the displacement of the external extensometer of the fractured material under test as described in the experimental results at time i, and e be the distance between the internal and external extensometers in the dimensional parameters.

[0014] Furthermore, the fracture toughness at that moment is calculated using a second formula, which is:

[0015]

[0016] Among them, J i Let be the fracture toughness at time i. U i Let B be the fracture plasticity at time i, B be the thickness of the material to be tested in the dimensional parameters, and a be the fracture plasticity. i Let B be the crack length at time i. N S represents the net thickness of the material to be tested in the dimensional parameters. i Let μ be the projected area of ​​the plastic region at time i, μ be Poisson's ratio, and ε be the area of ​​the plastic region at time i. f ε represents the fracture strain of the material to be tested. y ε is the yield strain of the material to be tested, K is the strength coefficient of the material to be tested, and ε t The value represents the true strain of the material to be tested, and n represents the hardening index of the material to be tested.

[0017] Furthermore, the process of determining the projected area of ​​the plastic zone at that moment based on the instantaneous radius of rotation is as follows:

[0018] The fracture morphology surface scanning detection is performed on the fractured material to obtain the fracture surface height curve;

[0019] The projected area of ​​the plastic zone at that moment is determined based on the fracture surface height curve and the instantaneous radius of rotation at that moment.

[0020] Another technical solution of the present invention to solve the above-mentioned technical problems is as follows: a system for determining the fracture toughness of metallic materials for pipelines, comprising:

[0021] The acquisition module is used to: determine the size parameters of the material to be tested, cut the material to be tested to obtain the fractured material to be tested, conduct a fracture test on the fractured material to be tested based on the unloading compliance program, and obtain the test results at different times. The material to be tested is the metal material of the pipe.

[0022] The first determining module is used to: determine the instantaneous radius of rotation at any given moment based on the dimensional parameters and the test results at any given moment, and determine the projected area of ​​the plastic zone at that moment based on the instantaneous radius of rotation at that moment;

[0023] The second determining module is used to: determine the fracture toughness of the material to be tested at that moment based on the size parameters and the projected area of ​​the plastic zone at that moment.

[0024] The beneficial effects of this invention are: This invention calculates fracture toughness using actual experimental fracture surfaces, which is more consistent with real-world conditions compared to empirical formulas, resulting in more accurate fracture toughness characterization. The method employs standard fracture tests and is simple to operate. Furthermore, this method can calculate fracture toughness JIC using only partial experimental data, making it well-suited for tests with missing or incomplete data. Therefore, it can serve as a method for determining the fracture toughness of components in engineering applications where data is lacking.

[0025] Furthermore, the instantaneous radius of rotation at that moment is calculated using a first formula, which is:

[0026]

[0027] Among them, R i Let V be the instantaneous rotation radius at time i. 1i V represents the extensometer displacement of the fractured material under test at time i, as described in the experimental results. 2i Let be the displacement of the external extensometer of the fractured material under test as described in the experimental results at time i, and e be the distance between the internal and external extensometers in the dimensional parameters.

[0028] Furthermore, the fracture toughness at that moment is calculated using a second formula, which is:

[0029]

[0030] Among them, J i Let be the fracture toughness at time i. U i Let B be the fracture plasticity at time i, B be the thickness of the material to be tested in the dimensional parameters, and a be the fracture plasticity. i Let B be the crack length at time i. N S represents the net thickness of the material to be tested in the dimensional parameters. i Let μ be the projected area of ​​the plastic region at time i, μ be Poisson's ratio, and ε be the area of ​​the plastic region at time i. f ε represents the fracture strain of the material to be tested. y ε is the yield strain of the material to be tested, K is the strength coefficient of the material to be tested, and ε t The value represents the true strain of the material to be tested, and n represents the hardening index of the material to be tested.

[0031] Furthermore, the process of determining the projected area of ​​the plastic zone at that moment based on the instantaneous radius of rotation is as follows:

[0032] The fracture morphology surface scanning detection is performed on the fractured material to obtain the fracture surface height curve;

[0033] The projected area of ​​the plastic zone at that moment is determined based on the fracture surface height curve and the instantaneous radius of rotation at that moment.

[0034] Another technical solution of the present invention to solve the above-mentioned technical problems is as follows: a storage medium storing instructions, wherein when a computer reads the instructions, the computer executes the method described in any of the above-mentioned methods.

[0035] The beneficial effects of this invention are: This invention calculates fracture toughness using actual experimental fracture surfaces, which is more consistent with real-world conditions compared to empirical formulas, resulting in more accurate fracture toughness characterization. The method employs standard fracture tests and is simple to operate. Furthermore, this method can calculate fracture toughness JIC using only partial experimental data, making it well-suited for tests with missing or incomplete data. Therefore, it can serve as a method for determining the fracture toughness of components in engineering applications where data is lacking.

[0036] Another technical solution of the present invention to solve the above-mentioned technical problems is as follows: an electronic device, including the above-mentioned storage medium and a processor that executes the instructions in the above-mentioned storage medium.

[0037] The beneficial effects of this invention are: This invention calculates fracture toughness using actual experimental fracture surfaces, which is more consistent with real-world conditions compared to empirical formulas, resulting in more accurate fracture toughness characterization. The method employs standard fracture tests and is simple to operate. Furthermore, this method can calculate fracture toughness JIC using only partial experimental data, making it well-suited for tests with missing or incomplete data. Therefore, it can serve as a method for determining the fracture toughness of components in engineering applications where data is lacking. Attached Figure Description

[0038] Figure 1 This is a schematic flowchart illustrating an embodiment of a method for determining the fracture toughness of a metallic material in a pipe according to the present invention.

[0039] Figure 2 A structural framework diagram provided for an embodiment of the fracture toughness determination system for a pipe made of metallic material according to the present invention;

[0040] Figure 3 This is a schematic diagram of the projected area of ​​the plastic zone after the first rotation, provided in an embodiment of the method for determining the fracture toughness of a pipe's metallic material according to the present invention.

[0041] Figure 4 This is a schematic diagram of the projected area of ​​the plastic zone after the second rotation, provided in an embodiment of the method for determining the fracture toughness of a pipe's metallic material according to the present invention.

[0042] Figure 5 This is a schematic diagram of the projected area of ​​the plastic zone after the third rotation, provided in an embodiment of the method for determining the fracture toughness of a pipe's metallic material according to the present invention.

[0043] Figure 6 This is a schematic diagram of the projected area of ​​the plastic zone after the fourth rotation, provided in an embodiment of the method for determining the fracture toughness of a pipe's metallic material according to the present invention.

[0044] Figure 7 A schematic diagram of the JR resistance curve provided in an embodiment of the method for determining the fracture toughness of a pipe's metallic material according to the present invention;

[0045] Figure 8 This is a schematic diagram of a CT sample provided in an embodiment of the method for determining the fracture toughness of a pipe's metallic material according to the present invention.

[0046] The attached diagram lists the components represented by each number as follows:

[0047] 1. External extensometer, 2. Internal extensometer, 3. CT sample. Detailed Implementation

[0048] The principles and features of the present invention are described below. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0049] like Figure 1 As shown, a method for determining the fracture toughness of a metallic material in a pipe includes:

[0050] The dimensional parameters of the material to be tested are determined, the material to be tested is cut open to obtain the fractured material to be tested, and a fracture test is performed on the fractured material to be tested based on the unloading compliance program to obtain the test results at different times. The material to be tested is the metal material of the pipe.

[0051] Based on the dimensional parameters and the test results at any given moment, determine the instantaneous radius of rotation at that moment, and then determine the projected area of ​​the plastic zone at that moment based on the instantaneous radius of rotation at that moment.

[0052] The fracture toughness of the material under test at that moment is determined based on the dimensional parameters and the projected area of ​​the plastic zone at that moment.

[0053] In some possible implementations, this invention calculates fracture toughness using actual experimental fracture surfaces, which is more consistent with real-world conditions and provides a more accurate characterization of fracture toughness compared to empirical formulas. The method employs standard fracture tests and is simple to operate. Furthermore, this method can calculate fracture toughness JIC using only partial experimental data, making it well-suited for tests with missing or incomplete data. Therefore, it can serve as a method for determining the fracture toughness of components to address the problem of insufficient data in engineering applications.

[0054] It should be noted that the metal to be tested will be referred to as CT sample 3 or sample in the following text.

[0055] 1) According to GB / T 21143-2014 "Unified Test Method for Quasi-Static Fracture Toughness of Metallic Materials", the dimensional parameters of CT specimen 3 are determined. The dimensional parameters are the distance e between the inner and outer extensometers 1, the specimen thickness B, and the net specimen thickness B. N ;

[0056] 2) The CT specimen 3 fracture test was carried out using the unloading compliance program, and the displacement V of the inner extensometer 2 (load line) was recorded at different times. 1i External extensometer 1 (notch) displacement V 2i The load-displacement curves from the experiment are shown. Note that the unloading compliance procedure uses the algorithm given above, which is existing technology. This procedure can be used to obtain the crack length 'a' at different times. i .

[0057] For example, by performing a fracture test on CT specimen 3 using an unloading compliance program, the displacement V at times 2, 3, 4, and 5 seconds was obtained. 1i : 1, 3, 5, 7 and V 2i : 2, 4, 6, 8.

[0058] 3) Scan the upper and lower fracture morphology surfaces of the test specimen after the test, and record the fracture surface height curve of the fracture morphology surface, that is, the curve corresponding to the small height change on the fracture surface. This curve is the fracture surface height curve.

[0059] 4) The instantaneous radius of rotation R of CT specimen 3 is calculated using the plastic hinge assumption and the definition of the rotation factor. The input parameters include the displacement V of the extensometer 2. 1i External extensometer 1 displacement V 2i The instantaneous radius of rotation R of CT specimen 3 is calculated using the following formula, based on the distance e between the inner and outer extensometers 1 and the plastic hinge assumption and the definition of the rotation factor:

[0060]

[0061] Among them, R i Let V be the instantaneous rotation radius at time i. 1i The displacement of the extensometer 2 of the fractured material under test described in the experimental results at time i is expressed in meters (m) and volume (V). 2i denoted as the displacement of the outer extensometer 1 at time i of the fractured material described in the experimental results, in meters (m), and e is the distance between the inner and outer extensometers 1 in the dimensional parameters, in meters (m).

[0062] For example, the instantaneous rotation radius at the 2nd, 3rd, 4th, and 5th seconds can be calculated using the above formula, assuming it to be 3m, 7m, 5m, and 8m.

[0063] 5) Based on the instantaneous rotation radius R obtained in step 4), rotate the upper and lower fracture morphology surfaces and calculate the projected area S of the plastic zone at different times. i This rotation is a fixed angle rotated at a fixed time interval.

[0064] For example, rotate the fractured specimen by 10° every 10 seconds. After the first rotation, rotate both the upper and lower sub-species. The projected area of ​​the plastic zone at the 2nd, 3rd, 4th, and 5th seconds of the current cycle can be calculated using the instantaneous rotation radius at the 2nd, 3rd, 4th, and 5th seconds. Note that different radii are needed for area calculation at different times. For example, at the 4th second of the current cycle, the instantaneous rotation radius at that moment is 5m, as shown in the example above. Therefore, the calculation of the projected area of ​​the plastic zone at that moment requires the data of 5m.

[0065] 6) Based on the integral definition of J and the plastic fracture energy equation, plot the JR resistance curve to finally obtain the fracture toughness JIC.

[0066]

[0067] Among them, J i Let be the fracture toughness at time i. U i Let B be the fracture plasticity at time i, B be the thickness of the material to be tested in the dimensional parameters, and a be the fracture plasticity. i Let B be the crack length at time i. N S represents the net thickness of the material to be tested in the dimensional parameters. i Let μ be the projected area of ​​the plastic region at time i, μ be Poisson's ratio, and ε be the area of ​​the plastic region at time i. f ε represents the fracture strain of the material to be tested. y ε is the yield strain of the material to be tested, K is the strength coefficient of the material to be tested, and ε t The value represents the true strain of the material to be tested, and n represents the hardening index of the material to be tested.

[0068] Example 1, such as Figure 8 As shown, the instantaneous rotation radius R of CT sample 3 is calculated using the first formula. The input parameters include the displacement of inner extensometer 2, the displacement of outer extensometer 1, the distance between inner and outer extensometer 1, and the crack length calculated by the unloading compliance method.

[0069] Based on the obtained instantaneous rotation radius R, the upper and lower fracture morphology surfaces (fracture surface height curves) are rotated, and the projected area of ​​the plastic zone at different times is calculated using software. The JR resistance curve is determined by the projected area of ​​the plastic zone and the second formula.

[0070] The following is a specific example to illustrate this.

[0071] 1) The physical and material parameters of the fractured specimens are shown in Table 1 and Table 2, respectively.

[0072] Table 1 Physical parameters of CT sample 3

[0073] Sample thickness Net thickness of the sample Internal and external extensometer distance 1 25.5mm 19.3mm 12mm

[0074] Table 2 Material parameters of CT sample 3

[0075] Poisson's ratio Strength coefficient Hardening index Yield strain Fracture strain 0.3 750MPa 0.28 0.03 0.23

[0076] 2) Calculate the instantaneous radius of rotation R according to Formula 1, and rotate the upper and lower fracture morphology surfaces, such as... Figure 3 , 4 As shown in Figures 5 and 6.

[0077] 3) Calculate the JR resistance curve according to formulas 2 and 3, such as... Figure 7 As shown, the fracture toughness JIC = 620.90 KJ / m2 was obtained.

[0078] Preferably, in any of the above embodiments, the instantaneous radius of rotation at that moment is calculated using a first formula, which is:

[0079]

[0080] Among them, R i Let V be the instantaneous rotation radius at time i. 1i V represents the displacement of the extensometer 2 of the fractured material under test at time i, as described in the experimental results. 2i Let be the displacement of the outer extensometer 1 of the fractured material under test as described in the experimental results at time i, and e be the distance between the inner and outer extensometers 1 in the dimensional parameters.

[0081] Preferably, in any of the above embodiments, the fracture toughness at that moment is calculated using a second formula, which is:

[0082]

[0083] Among them, J i Let be the fracture toughness at time i. U i Let B be the fracture plasticity at time i, B be the thickness of the material to be tested in the dimensional parameters, and a be the fracture plasticity. i Let B be the crack length at time i. N S represents the net thickness of the material to be tested in the dimensional parameters. i Let μ be the projected area of ​​the plastic region at time i, μ be Poisson's ratio, and ε be the area of ​​the plastic region at time i. f For fracture strain, ε y Where ε is the yield strain, K is the strength coefficient, and ε is the yield strain. t For the actual strain, n is the hardening exponent.

[0084] Preferably, in any of the above embodiments, it further includes:

[0085] The fracture morphology surface scanning detection is performed on the fractured material to obtain the fracture surface height curve.

[0086] like Figure 2 As shown, a system for determining the fracture toughness of a metallic material in a pipe includes:

[0087] The acquisition module 100 is used to: determine the size parameters of the material to be tested, cut the material to be tested to obtain the fractured material to be tested, conduct a fracture test on the fractured material to be tested based on the unloading compliance program, and obtain the test results at different times. The material to be tested is the metal material of the pipe.

[0088] The first determining module 200 is used to: determine the instantaneous radius of rotation at any given moment based on the dimensional parameters and the test results at any given moment, and determine the projected area of ​​the plastic zone at that moment based on the instantaneous radius of rotation at that moment;

[0089] The second determining module 300 is used to: determine the fracture toughness of the material to be tested at a given moment based on the dimensional parameters and the projected area of ​​the plastic zone at that moment.

[0090] In some possible implementations, this invention calculates fracture toughness using actual experimental fracture surfaces, which is more consistent with real-world conditions and provides a more accurate characterization of fracture toughness compared to empirical formulas. The method employs standard fracture tests and is simple to operate. Furthermore, this method can calculate fracture toughness JIC using only partial experimental data, making it well-suited for tests with missing or incomplete data. Therefore, it can serve as a method for determining the fracture toughness of components to address the problem of insufficient data in engineering applications.

[0091] Preferably, in any of the above embodiments, the instantaneous radius of rotation at that moment is calculated using a first formula, which is:

[0092]

[0093] Among them, R i Let V be the instantaneous rotation radius at time i. 1i V represents the displacement of the extensometer 2 of the fractured material under test at time i, as described in the experimental results. 2i Let be the displacement of the outer extensometer 1 of the fractured material under test as described in the experimental results at time i, and e be the distance between the inner and outer extensometers 1 in the dimensional parameters.

[0094] Preferably, in any of the above embodiments, the fracture toughness at that moment is calculated using a second formula, which is:

[0095]

[0096] Among them, J i Let be the fracture toughness at time i. U i Let B be the fracture plasticity at time i, B be the thickness of the material to be tested in the dimensional parameters, and a be the fracture plasticity. i Let B be the crack length at time i. N S represents the net thickness of the material to be tested in the dimensional parameters. i Let μ be the projected area of ​​the plastic region at time i, μ be Poisson's ratio, and ε be the area of ​​the plastic region at time i. f ε represents the fracture strain of the material to be tested. y ε is the yield strain of the material to be tested, K is the strength coefficient of the material to be tested, and ε t The value represents the true strain of the material to be tested, and n represents the hardening index of the material to be tested.

[0097] Preferably, in any of the above embodiments, the process of determining the projected area of ​​the plastic zone at that moment based on the instantaneous radius of rotation at that moment specifically involves:

[0098] The fracture morphology surface scanning detection is performed on the fractured material to obtain the fracture surface height curve;

[0099] The projected area of ​​the plastic zone at that moment is determined based on the fracture surface height curve and the instantaneous radius of rotation at that moment.

[0100] Another technical solution of the present invention to solve the above-mentioned technical problems is as follows: a storage medium storing instructions, wherein when a computer reads the instructions, the computer executes the method described in any of the above-mentioned methods.

[0101] In some possible implementations, this invention calculates fracture toughness using actual experimental fracture surfaces, which is more consistent with real-world conditions and provides a more accurate characterization of fracture toughness compared to empirical formulas. The method employs standard fracture tests and is simple to operate. Furthermore, this method can calculate fracture toughness JIC using only partial experimental data, making it well-suited for tests with missing or incomplete data. Therefore, it can serve as a method for determining the fracture toughness of components to address the problem of insufficient data in engineering applications.

[0102] Another technical solution of the present invention to solve the above-mentioned technical problems is as follows: an electronic device, including the above-mentioned storage medium and a processor that executes the instructions in the above-mentioned storage medium.

[0103] In some possible implementations, this invention calculates fracture toughness using actual experimental fracture surfaces, which is more consistent with real-world conditions and provides a more accurate characterization of fracture toughness compared to empirical formulas. The method employs standard fracture tests and is simple to operate. Furthermore, this method can calculate fracture toughness JIC using only partial experimental data, making it well-suited for tests with missing or incomplete data. Therefore, it can serve as a method for determining the fracture toughness of components to address the problem of insufficient data in engineering applications.

[0104] Readers should understand that in the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0105] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the method embodiments described above are merely illustrative. For instance, the division of steps is only a logical functional division, and there may be other division methods in actual implementation. For example, multiple steps may be combined or integrated into another step, or some features may be ignored or not executed.

[0106] If the above methods are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0107] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for determining the fracture toughness of a metallic material for a pipe, characterized in that, include: The dimensional parameters of the material to be tested are determined, the material to be tested is cut open to obtain the fractured material to be tested, and a fracture test is performed on the fractured material to be tested based on the unloading compliance program to obtain the test results at different times. The material to be tested is the metal material of the pipe. Based on the dimensional parameters and the test results at any given moment, determine the instantaneous radius of rotation at that moment, and then determine the projected area of ​​the plastic zone at that moment based on the instantaneous radius of rotation at that moment. The fracture toughness of the material under test at that moment is determined based on the dimensional parameters and the projected area of ​​the plastic zone at that moment. The fracture toughness at that moment is calculated using a second formula, which is: ； in, Let be the fracture toughness at time i. , Let B represent the fracture plasticity at time i, and B be the thickness of the material under test in the dimensional parameters. Let be the crack length at time i. The net thickness of the material to be tested is a parameter in the dimensional parameters. Let be the projected area of ​​the plastic region at time i. Poisson's ratio, The fracture strain of the material to be tested. Let K be the yield strain of the material to be tested, and K be the strength coefficient of the material to be tested. The value represents the true strain of the material to be tested, and n represents the hardening index of the material to be tested.

2. The method for determining the fracture toughness of a pipe's metallic material according to claim 1, characterized in that, The instantaneous radius of rotation at that moment is calculated using a first formula, which is: ； in, Let be the instantaneous rotation radius at time i. The extensometer displacement of the fractured test material at time i, as described in the experimental results. Let be the displacement of the external extensometer of the fractured material under test as described in the experimental results at time i, and e be the distance between the internal and external extensometers in the dimensional parameters.

3. The method for determining the fracture toughness of a pipe's metallic material according to claim 1, characterized in that, The process of determining the projected area of ​​the plastic zone at that moment based on the instantaneous radius of rotation is as follows: The fracture morphology surface scanning detection is performed on the fractured material to obtain the fracture surface height curve; The projected area of ​​the plastic zone at that moment is determined based on the fracture surface height curve and the instantaneous radius of rotation at that moment.

4. A system for determining the fracture toughness of metallic materials used in pipelines, characterized in that, include: The acquisition module is used to: determine the size parameters of the material to be tested, cut the material to be tested to obtain the fractured material to be tested, conduct a fracture test on the fractured material to be tested based on the unloading compliance program, and obtain the test results at different times. The material to be tested is the metal material of the pipe. The first determining module is used to: determine the instantaneous radius of rotation at any given moment based on the dimensional parameters and the test results at any given moment, and determine the projected area of ​​the plastic zone at that moment based on the instantaneous radius of rotation at that moment; The second determining module is used to: determine the fracture toughness of the material to be tested at that moment based on the dimensional parameters and the projected area of ​​the plastic zone at that moment; The fracture toughness at that moment is calculated using a second formula, which is: ； in, Let be the fracture toughness at time i. , Let B represent the fracture plasticity at time i, and B be the thickness of the material under test in the dimensional parameters. Let be the crack length at time i. The net thickness of the material to be tested is a parameter in the dimensional parameters. Let be the projected area of ​​the plastic region at time i. Poisson's ratio, The fracture strain of the material to be tested. Let K be the yield strain of the material to be tested, and K be the strength coefficient of the material to be tested. The value represents the true strain of the material to be tested, and n represents the hardening index of the material to be tested.

5. The system for determining the fracture toughness of metallic materials for pipelines according to claim 4, characterized in that, The instantaneous radius of rotation at that moment is calculated using a first formula, which is: ； in, Let be the instantaneous rotation radius at time i. The extensometer displacement of the fractured test material at time i, as described in the experimental results. Let be the displacement of the external extensometer of the fractured material under test as described in the experimental results at time i, and e be the distance between the internal and external extensometers in the dimensional parameters.

6. The system for determining the fracture toughness of a pipe's metallic material according to claim 4, characterized in that, The process of determining the projected area of ​​the plastic zone at a given moment based on the instantaneous radius of rotation is as follows: The fracture morphology surface scanning detection is performed on the fractured material to obtain the fracture surface height curve; The projected area of ​​the plastic zone at that moment is determined based on the fracture surface height curve and the instantaneous radius of rotation at that moment.

7. A storage medium, characterized in that, The medium stores instructions that, when read by a computer, cause the computer to execute the method as described in any one of claims 1 to 3.

8. An electronic device, characterized in that, Includes the storage medium of claim 7 and a processor that executes instructions within the storage medium.

Images