Fracture toughness testing method and system, electronic equipment and storage medium

Abstract

The invention discloses a fracture toughness testing method and system, electronic equipment and a storage medium, and relates to the technical field of fracture toughness tests.The method comprises the steps that in the process of carrying out a fracture toughness test on a sample, a DIC system is used for measuring and obtaining a curve of crack opening displacement at multiple preset positions of a preset notch of the sample along with time; and obtaining a critical point in the curve of the crack opening displacement of each preset position along with the time change, performing linear fitting, and then determining the crack opening displacement at the tip of the preset gap. Based on the digital image technology, the fracture deformation process of the sample can be truly and effectively reflected, the crack opening displacement at the tip of the preset notch of the sample is accurately determined, the testing efficiency is high, the testing result is accurate and reliable, and the fracture toughness of the sample at multiple temperatures can be rapidly and accurately measured.

Description

Background Art

[0002] Pipeline transportation is a large-scale and economical way to transport oil and natural gas. Pipeline failure can have serious consequences. Analysis of historical data shows that the main causes of pipeline leakage and rupture are defects in pipeline design and manufacturing, environmental impacts and human factors. The probability of an accident in a pipeline is related to whether there are defects in the pipeline, the size of the defects and fracture control. Fracture control is the main factor in controlling risks.

[0003] Structural fracture resistance depends on characterizing the fracture properties of pipeline steels, which are characterized by resistance to crack initiation and propagation. As toughness increases, the crack tip becomes increasingly blunt. In sufficiently tough steels, the degree of blunting is such that failures controlled by fracture tend to be plastically controlled, and the response becomes insensitive to increasing toughness. Fracture toughness refers to the resistance of a material to stable crack growth. In the late 1950s, due to concerns about the fracture behavior occurring in the pipeline industry, the industry adopted the then-popular Charpy V-Notch (CVN) impact test to determine the toughness of pipeline steels. The CVN test is often supplemented by a drop weight tear test (DWTT) to define the fracture mode and ensure that fracture occurs in a ductile manner at the service temperature. Both CVN and DWTT are dynamic test methods. With the development of fracture mechanics, material fracture toughness can also be measured using quasi-static laboratory fracture tests, such as plane strain or plane stress fracture toughness tests, J-integral JR curve tests, or crack opening displacement (CTOD) tests.

[0004] Since the fracture toughness test has high requirements on specimens and test measurement methods, the oil and gas pipeline industry still uses the simple and convenient Charpy impact test method to test the fracture toughness of materials, which has the disadvantages of low test efficiency and low test result accuracy. Summary of the invention

[0005] The technical problem to be solved by the present invention is to address the deficiencies of the prior art and specifically provide a fracture toughness testing method, system, electronic device and storage medium, as follows:

[0006] 1) In the first aspect, the present invention provides a fracture toughness testing method, and the specific technical scheme is as follows:

[0007] In the process of fracture toughness test on the sample, the DIC system is used to measure the curve of crack opening displacement at multiple preset positions of the preset notch of the sample versus time;

[0008] Obtain the critical point in the curve of crack opening displacement changing with time at each preset position, and perform linear fitting, in which the horizontal axis of the fitted straight line is the distance between the preset position and the tip of the preset notch, and the vertical axis is the measured crack opening displacement;

[0009] The crack opening displacement corresponding to when the abscissa is 0 is determined as the crack opening displacement at the tip of the preset notch.

[0010] The beneficial effects of a fracture toughness testing method provided by the present invention are as follows:

[0011] Based on digital imaging (DIC) technology, it can truly and effectively reflect the fracture deformation process of the sample and accurately determine the crack opening displacement at the tip of the preset notch of the sample. It has high test efficiency, accurate and reliable test results, and can quickly and accurately measure the fracture toughness of the sample at multiple temperatures.

[0012] Based on the above solution, a fracture toughness testing method of the present invention can also be improved as follows.

[0013] Furthermore, it also includes:

[0014] According to the crack opening displacement at the tip of the preset notch, the crack tip opening displacement of the specimen in the critical state is calculated.

[0015] Furthermore, in the process of conducting a fracture toughness test on the sample, the DIC system is used to measure the curves of crack opening displacement at multiple preset positions of the preset notch of the sample over time, including:

[0016] In the DIC system, a virtual extensometer is set for each preset position, and a curve of crack opening displacement changing with time at multiple preset positions of the preset notch of the specimen is measured by setting multiple virtual extensometers.

[0017] Furthermore, the fracture toughness test is a low temperature fracture toughness test.

[0018] 2) In the second aspect, the present invention also provides a fracture toughness testing system, and the specific technical solution is as follows:

[0019] It includes a crack opening displacement curve acquisition module, a linear fitting module and a crack opening displacement determination module;

[0020] The crack opening displacement curve acquisition module is used to: in the process of performing a fracture toughness test on a sample, use the DIC system to measure and obtain a curve of crack opening displacement changing with time at multiple preset positions of a preset notch of the sample;

[0021] The linear fitting module is used to obtain the critical point in the curve of crack opening displacement of each preset position versus time, and perform linear fitting. In the fitted straight line, the horizontal axis is the distance between the preset position and the tip of the preset notch, and the vertical axis is the measured crack opening displacement.

[0022] The crack opening displacement determination module is used to determine the crack opening displacement corresponding to when the horizontal coordinate is 0 as the crack opening displacement at the tip of the preset notch.

[0023] Based on the above solution, the fracture toughness testing system of the present invention can also be improved as follows.

[0024] Furthermore, it also includes a critical crack tip opening displacement determination module, which is used to calculate the crack tip opening displacement of the sample in a critical state according to the crack opening displacement at the tip of the preset notch.

[0025] Furthermore, the crack opening displacement curve acquisition module is specifically used for:

[0026] In the DIC system, a virtual extensometer is set for each preset position, and a curve of crack opening displacement changing with time at multiple preset positions of the preset notch of the specimen is measured by setting multiple virtual extensometers.

[0027] Furthermore, the fracture toughness test is a low temperature fracture toughness test.

[0028] 3) In a third aspect, the present invention further provides an electronic device, comprising a processor, the processor being coupled to a memory, the memory storing at least one computer program, the at least one computer program being loaded and executed by the processor, so that the electronic device can implement any one of the above-mentioned fracture toughness testing methods.

[0029] 4) In a fourth aspect, the present invention further provides a computer-readable storage medium, in which at least one computer program is stored, and the at least one computer program is loaded and executed by a processor so that a computer implements any one of the above-mentioned fracture toughness testing methods.

[0030] It should be noted that the beneficial effects achieved by the technical solutions of the second to fourth aspects of the present invention and the corresponding possible implementation methods can be found in the above-mentioned technical effects of the first aspect and its corresponding possible implementation methods, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0032] Figure 1A schematic flow chart of a fracture toughness testing method according to an embodiment of the present invention;

[0033] Figure 2 It is a schematic diagram of the structure of the three-point bending specimen;

[0034] Figure 3 The processed speckle sample;

[0035] Figure 4 Schematic diagram of DIC equipment;

[0036] Figure 5 Schematic diagram of crack opening displacement curve measured by virtual extensometer;

[0037] Figure 6 is the elongation variation curve of the extensometer;

[0038] Figure 7 A schematic diagram for obtaining the crack opening displacement at the tip of a preset notch;

[0039] Figure 8 Schematic diagram of crack tip opening displacement;

[0040] Fig. 9 It is a schematic diagram of the structure of the blank;

[0041] Fig.10 A structural schematic diagram of a fracture toughness testing system according to an embodiment of the present invention;

[0042] Fig.11 The figure is a schematic diagram of the structure of an electronic device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0043] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0044] like Figure 1 As shown, a fracture toughness testing method according to an embodiment of the present invention comprises the following steps:

[0045] S1. During the fracture toughness test of the sample, the DIC system is used to measure the curve of the crack opening displacement at multiple preset positions of the preset notch of the sample versus time.

[0046] The specimen may be a three-point bending specimen, or may be set according to actual conditions.

[0047] S2. Obtain the critical point in the curve of crack opening displacement of each preset position versus time, and perform linear fitting. In the fitted straight line, the horizontal axis is the distance between the preset position and the tip of the preset notch, and the vertical axis is the measured crack opening displacement.

[0048] S3. The crack opening displacement corresponding to when the horizontal coordinate is 0 is determined as the crack opening displacement at the tip of the preset notch.

[0049] The preset notch is a notch obtained by machining the sample in advance, which can also be called a preset machining notch.

[0050] In a fracture toughness testing method of an embodiment of the present invention, based on digital imaging (DIC) technology, it can truly and effectively reflect the fracture deformation process of the sample, accurately determine the crack opening displacement at the tip of the preset notch of the sample, have high test efficiency, and the test results are accurate and reliable. It can also quickly and accurately measure the fracture toughness of the sample at multiple temperatures.

[0051] Optionally, in the above technical solution, it also includes:

[0052] S4. Calculate the crack tip opening displacement of the specimen in the critical state based on the crack opening displacement at the tip of the preset notch.

[0053] Optionally, in S1, during the fracture toughness test of the sample, a DIC system is used to measure a curve of crack opening displacement at a plurality of preset positions of a preset notch of the sample over time, including:

[0054] S10. In the DIC system, a virtual extensometer is respectively set for each preset position, and a curve of crack opening displacement changing with time at multiple preset positions of the preset notch of the specimen is measured by using the multiple virtual extensometers.

[0055] Optionally, the fracture toughness test is a low temperature fracture toughness test.

[0056] The present invention is described by taking a low temperature fracture toughness test as an example. The equipment used in the test includes: a fatigue testing machine, a cooling cycle system, a fracture extensometer and a DIC system. The DIC system includes a high-precision and high-resolution static camera, electronic control hardware and analysis software modules, image acquisition and processing software, etc. The test principle is as follows:

[0057] During the low-temperature fracture toughness test, the DIC system is used to measure the surface displacement and strain distribution of the sample, and the software is used for data analysis. The relationship between the pixel point and the sample size is established and then calculated. The virtual extensometer is used to mark the elongation of different positions of the machining notch. The displacement before expansion at different positions is extracted from the curve of the surface displacement on both sides of the crack at different positions with the loading load. The least squares method is then used for linear fitting. The intersection of the fitting line and the vertical axis is the crack opening displacement COD at the tip of the preset notch. The specific test process is as follows:

[0058] S101. Process three-point bending specimens according to the test standard. Specifically, process three-point bending specimens according to the test standard GB / T21143. Specifically:

[0059] S1010. Use mechanical or thermal processing methods to cut blanks from steel pipes. The blanks cannot be flattened.

[0060] S1011. Use mechanical cutting or thermal cutting to remove a portion of about one steel pipe thickness around the blank to avoid the impact of thermal cutting on the performance of the blank.

[0061] S1012. Process the basic three-point bending specimen according to the test standard. The structure of the three-point bending specimen is as follows: Figure 2 shown.

[0062] S1013. Measure and record the basic parameters of the three-point bending specimen, mark the arrival point of the pre-crack, and clamp it to the fatigue testing machine for pre-crack. The process of pre-crack fatigue crack is as follows:

[0063] Place the three-point bending specimen on the fatigue testing machine, place the three-point bending specimen correctly, align the pressure head with the mid-span position of the three-point bending specimen, and use a vernier caliper to check repeatedly to prevent the three-point bending specimen from being skewed. Then follow the operating steps of the fatigue testing machine, set the maximum and minimum values ​​of the alternating load, the vibration frequency is 25HZ, start the fatigue testing machine, and then perform fatigue crack prefabrication. The maximum fatigue prefabrication crack load is determined according to the following formula:

[0064]

[0065] Among them, F f is the maximum fatigue pre-crack force; R p0.2 is the non-proportional extension strength of the material at the fatigue crack prefabrication temperature, W represents the width, B represents the thickness, a0 represents the crack length, and S represents the span.

[0066] S102. According to the requirements of the DIC equipment, local painting and speckle printing are performed on the processing notch of the three-point bending specimen, such as Figure 3 As shown, specifically:

[0067] S1020. Remove the fine hair debris on the surface of the three-point bending specimen and clean the surface of the three-point bending specimen with alcohol.

[0068] S1021. Label the three-point bending specimens, and use a micrometer and a vernier caliper to measure and record the initial geometric parameters of the three-point bending specimens, such as width W, thickness B, etc.;

[0069] S1022. Spray matte white primer evenly on the surface to be tested on the three-point bending specimen, place it in a cool and ventilated place to dry, spray matte black speckle evenly on the matte white primer, and let it dry.

[0070] S103. Place the three-point bending specimen on the testing machine according to the specific requirements of the test. Specifically:

[0071] The low-temperature test box is placed. The length, width and height of the low-temperature test box are 750mm, 800mm and 750mm respectively. A 145mm×145mm square window is set at the front of the low-temperature test box for observation by the high-precision and high-resolution static camera of the DIC system. The high-precision and high-resolution static camera in the DIC system collects image information through the observation window (window) of the low-temperature test box. The observation window of the low-temperature test box adopts vacuum double-layer glass, which can prevent fog condensation on the observation window in the low-temperature test environment.

[0072] S104. Place the DIC system in a position where the fracture process of the three-point bending specimen can be clearly photographed, and calibrate the system, such as Figure 4 As shown, specifically:

[0073] S1040. Install the high-precision and high-resolution static camera in the DIC system on a tripod, and connect the high-precision and high-resolution static camera to the acquisition computer through a data cable and a data acquisition card, and make the lens field of view of the high-precision and high-resolution static camera face the three-point bending specimen.

[0074] S1041. Adjust the focus of the high-precision and high-resolution still camera and turn it to the maximum aperture position.

[0075] S1042. Adjust the reflection effect, cover one light source, and fine-tune the two cameras.

[0076] S1043. Adjust the aperture and focal length of the high-precision and high-resolution static camera so that the image displayed on the acquisition computer is clear.

[0077] S105, test temperature adjustment: Use a cooling circulation system based on liquid nitrogen cooling to adjust the temperature to the test required temperature (room temperature or low temperature, etc.), and then keep the entire three-point bending specimen warm. After the temperature in the low-temperature test chamber is stable and maintained for 20 minutes, execute S106.

[0078] S106. Start the fatigue testing machine to conduct a low-temperature fracture toughness test.

[0079] Among them, when clamping the three-point bending specimen, it must be ensured that the load applied to the three-point bending specimen is loaded in the axial direction. After clamping the three-point bending specimen, check whether the three-point bending specimen is subjected to excessive force. First, reset the force value of the fatigue testing machine, then connect the lower tie rod, insert the lower fixture pin, complete the connection of the tie rod and the installation of the three-point bending specimen.

[0080] S107. Collect data using DIC system software, establish the relationship between pixel points and size, and then perform calculations. Use a virtual extensometer to mark the elongation of different positions of the machining notch. From the curve of surface displacement on both sides of the crack at different positions changing with loading, extract the critical displacement before expansion at different positions.

[0081] Four virtual extensometers are set in the DIC system, which are respectively named as the first virtual extensometer, the second virtual extensometer, the third virtual extensometer and the fourth virtual extensometer, and are used to record and measure the crack opening displacement curves at different positions, such as Figure 5 and Figure 6 shown.

[0082] S108, perform linear fitting, the intersection of the fitting line and the longitudinal axis is the crack opening distance at the processing notch, specifically:

[0083] Extract four extensometer elongation data and define Figure 6 The mutation point in each curve is the critical point. The least square method is used for linear fitting. Figure 7 As shown in the figure, the horizontal axis r is the distance between the end point of the extensometer and the vertex of the machined notch, and the vertical axis Δl is the elongation of the virtual extensometer. The intersection of the fitting curve and the vertical axis is the crack opening displacement at the tip of the preset notch.

[0084] S109. Calculate CTOD according to the following formula.

[0085] The opening displacement at the point where the critical crack tip retreats 0.2 mm before expansion is defined as the critical crack tip opening displacement δ 0.2 , this value can be obtained by using the COD value at the machining notch using the similar triangle relationship, that is:

[0086]

[0087] Among them, a f is the length of the prefabricated fatigue crack, L0 is the tip opening displacement of the machined notch, that is, the COD value obtained above, and the crack tip opening displacement at the critical state (that is, the crack tip opening displacement of the specimen at the critical state) CTOD (δ 0.2 ) Schematic diagram as Figure 8 After obtaining L0, substitute it into the above formula to calculate and obtain the CTOD value.

[0088] In another embodiment, comprising:

[0089] S201. Take a 1016mm diameter straight seam submerged arc welded pipe of X70 steel grade for oil and gas pipelines, with a thickness of about 25mm. Take a 300×300mm blank from the original steel pipe, cut it by thermal cutting, and mark the direction of the steel pipe on the blank, such as Fig. 9 shown.

[0090] S202. According to the requirements of "Metallic Materials - Unified Test Method for Quasi-static Fracture Toughness" (GBT / 21143), a transverse three-point bending specimen is taken from the blank. The specimen dimensions are: thickness B is 20 mm, height W is 40 mm, span is 2.3W, 92 mm, initial crack is 0.55W, side groove depth is 4 mm, side groove angle is 45°, such as Fig. 9 shown.

[0091] S203, measuring samples B, B N , W values ​​and record them, mark the arrival point of the prefabricated crack, and clamp them to the fatigue testing machine for pre-cracking; (the pre-cracking length of all specimens is the corresponding 0.1W);

[0092] S204. Perform local spray painting and speckle printing on the processed notch of the sample and let it dry.

[0093] S205. Clamp the pre-cracked specimen onto the universal testing machine.

[0094] S206, placing the DIC system at a position where the fracture process of the sample can be clearly photographed, connecting the acquisition computer to the camera via a data cable and a data acquisition card, making the lens field of view face the sample, and performing system calibration.

[0095] S207. Close the low-temperature test chamber, set the test temperature, and maintain it for 20 minutes after the temperature inside the chamber stabilizes.

[0096] S208. Start the test and stop when the sample is loaded to a force exceeding the maximum force.

[0097] S209, collect test temperature, crack opening displacement and image data, save the data, and observe whether there is any abnormal phenomenon.

[0098] S210, use the DIC system to analyze the data, establish the relationship between pixel points and size, and then calculate, use the virtual extensometer to mark the elongation of different positions of the machining notch. From the curve of the surface displacement of both sides of the crack at different positions with the load, extract the critical displacement before expansion at different positions, and perform linear fitting to obtain the COD value of the crack opening displacement at the tip of the machining notch.

[0099] S211, perform linear fitting to obtain COD value.

[0100] S212. Calculate and obtain CTOD.

[0101] The present invention proposes a fracture toughness test method based on digital imaging (DIC) technology. Through this test method, based on the non-contact measurement method of the optical video extensometer, the change of the speckle on the surface of the object can be analyzed, and the image-related area can be found through grayscale to calculate the displacement and strain distribution on the surface of the object. It can truly and effectively reflect the fracture deformation process of the sample, and finally obtain the crack opening displacement at the tip of the preset notch of the sample and the crack tip opening displacement CTOD of the sample in the critical state through curve fitting. This test method can quickly and accurately measure the fracture toughness of the sample at multiple temperatures, make up for the above-mentioned gaps and deficiencies in existing standards and technologies, and provide a reliable and fast test method for accurately predicting the fracture toughness of steel pipes.

[0102] In the above embodiments, although the steps are numbered S1, S2, etc., these are only specific embodiments given by the present invention. Those skilled in the art may adjust the execution order of S1, S2, etc. according to actual conditions, which is also within the protection scope of the present invention. It can be understood that in some embodiments, some or all of the above embodiments may be included.

[0103] like Fig.10 As shown, a fracture toughness testing system 200 according to an embodiment of the present invention includes a crack opening displacement curve acquisition module 201, a linear fitting module 202 and a crack opening displacement determination module 203;

[0104] The crack opening displacement curve acquisition module 201 is used to: in the process of performing a fracture toughness test on a sample, use a DIC system to measure and obtain a curve of crack opening displacement at multiple preset positions of a preset notch of the sample over time;

[0105] The linear fitting module 202 is used to obtain the critical point in the curve of crack opening displacement of each preset position versus time, and perform linear fitting. In the fitted straight line, the horizontal axis is the distance between the preset position and the tip of the preset notch, and the vertical axis is the measured crack opening displacement.

[0106] The crack opening displacement determination module 203 is used to determine the crack opening displacement corresponding to when the horizontal coordinate is 0 as the crack opening displacement at the tip of the preset notch.

[0107] Optionally, a critical crack tip opening displacement determination module is further included, and the critical crack tip opening displacement determination module is used to calculate the crack tip opening displacement of the sample in a critical state according to the crack opening displacement at the tip of a preset notch.

[0108] Optionally, in the above technical solution, the crack opening displacement curve acquisition module 201 is specifically used for:

[0109] In the DIC system, a virtual extensometer is set for each preset position, and a curve of crack opening displacement changing with time at multiple preset positions of the preset notch of the specimen is measured by setting multiple virtual extensometers.

[0110] Optionally, in the above technical solution, the fracture toughness test is a low-temperature fracture toughness test.

[0111] It should be noted that the beneficial effects of the fracture toughness testing system 200 provided in the above embodiment are the same as the beneficial effects of the fracture toughness testing method described above, which will not be described in detail here. In addition, when the system provided in the above embodiment realizes its functions, only the division of the above functional modules is used as an example. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the system can be divided into different functional modules according to actual conditions to complete all or part of the functions described above. In addition, the system and method embodiments provided in the above embodiment belong to the same concept, and the specific implementation process is detailed in the method embodiment, which will not be described in detail here.

[0112] like Fig.11 As shown, an electronic device 300 according to an embodiment of the present invention includes a processor 320, the processor 320 is coupled to a memory 310, and the memory 310 stores at least one computer program 330, and the at least one computer program 330 is loaded and executed by the processor 320, so that the electronic device 300 implements any of the above fracture toughness testing methods, specifically:

[0113] The electronic device 300 may have relatively large differences due to different configurations or performances, and may include one or more processors 320 (Central Processing Units, CPU) and one or more memories 310, wherein at least one computer program 330 is stored in the one or more memories 310, and the at least one computer program 330 is loaded and executed by the one or more processors 320, so that the electronic device 300 implements any fracture toughness test method provided in the above embodiments. Of course, the electronic device 300 may also have components such as a wired or wireless network interface, a keyboard, and an input and output interface for input and output. The electronic device 300 may also include other components for realizing the functions of the device, which will not be described in detail here. The electronic device may specifically be a computer, etc.

[0114] A computer-readable storage medium according to an embodiment of the present invention stores at least one computer program, and the at least one computer program is loaded and executed by a processor so that a computer implements any one of the above-mentioned fracture toughness testing methods.

[0115] Optionally, the computer-readable storage medium may be a read-only memory (ROM), a random access memory (RAM), a compact disc (CD-ROM), a magnetic tape, a floppy disk, an optical data storage device, and the like.

[0116] In an exemplary embodiment, a computer program product or a computer program is also provided, the computer program product or the computer program comprising computer instructions, the computer instructions being stored in a computer-readable storage medium. A processor of an electronic device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the electronic device performs any of the above-mentioned fracture toughness test methods.

[0117] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects and represent the definition of a specific order or sequence. The order of use of similar objects can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than the order shown or described.

[0118] Those skilled in the art know that the present invention can be implemented as a system, method or computer program product. Therefore, the present invention can be specifically implemented in the following forms, namely: it can be complete hardware, it can be complete software (including firmware, resident software, microcode, etc.), or it can be a combination of hardware and software, which is generally referred to as "circuit", "module" or "system" herein. In addition, in some embodiments, the present invention can also be implemented in the form of a computer program product in one or more computer-readable media, and the computer-readable medium contains computer-readable program code.

[0119] Any combination of one or more computer-readable media can be used. The computer-readable medium can be a computer-readable signal medium or a computer-readable storage medium. The computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or device, or any combination of the above. More specific examples of computer-readable storage media (a non-exhaustive list) include: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present invention, a computer-readable storage medium can be any tangible medium containing or storing a program, which can be used by an instruction execution system, device or device or used in combination with it.

[0120] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A fracture toughness testing method, characterized in that: include: In the process of performing a fracture toughness test on the sample, a curve of crack opening displacement at multiple preset positions of a preset notch of the sample changing with time is measured using a DIC system; Obtaining the critical point in the curve of crack opening displacement changing with time at each preset position, and performing linear fitting, wherein the horizontal coordinate of the fitted straight line is: the distance between the preset position and the tip of the preset notch, and the vertical coordinate is: the measured crack opening displacement; The crack opening displacement corresponding to when the abscissa is 0 is determined as the crack opening displacement at the tip of the preset notch.

2. A fracture toughness testing method according to claim 1, characterized in that: Also includes: The crack tip opening displacement of the sample in a critical state is calculated according to the crack opening displacement at the tip of the preset notch.

3. A fracture toughness testing method according to claim 1, characterized in that: In the process of conducting a fracture toughness test on a sample, a curve of crack opening displacement versus time at multiple preset positions of a preset notch of the sample is measured using a DIC system, including: In the DIC system, a virtual extensometer is respectively set for each preset position, and a curve of crack opening displacement changing with time at multiple preset positions of the preset notch of the sample is measured by using the multiple virtual extensometers.

4. A fracture toughness testing method according to any one of claims 1 to 3, characterized in that: The fracture toughness test is a low temperature fracture toughness test.

5. A fracture toughness testing system, characterized in that: It includes a crack opening displacement curve acquisition module, a linear fitting module and a crack opening displacement determination module; The crack opening displacement curve acquisition module is used to: in the process of performing a fracture toughness test on a sample, use a DIC system to measure and obtain a curve of crack opening displacement at multiple preset positions of a preset notch of the sample over time; The linear fitting module is used to obtain the critical point in the curve of crack opening displacement of each preset position versus time, and perform linear fitting, wherein the horizontal coordinate of the fitted straight line is the distance between the preset position and the tip of the preset notch, and the vertical coordinate is the measured crack opening displacement; The crack opening displacement determination module is used to determine the crack opening displacement corresponding to when the horizontal coordinate is 0 as the crack opening displacement at the tip of the preset notch.

6. A fracture toughness testing system according to claim 5, characterized in that: It also includes a critical crack tip opening displacement determination module, which is used to calculate the crack tip opening displacement of the sample in a critical state according to the crack opening displacement at the tip of the preset notch.

7. A fracture toughness testing system according to claim 6, characterized in that: The crack opening displacement curve acquisition module is specifically used for: In the DIC system, a virtual extensometer is respectively set for each preset position, and a curve of crack opening displacement changing with time at multiple preset positions of the preset notch of the sample is measured by using the multiple virtual extensometers.

8. A fracture toughness testing system according to any one of claims 5 to 7, characterized in that: The fracture toughness test is a low temperature fracture toughness test.

9. An electronic device, characterized in that: The electronic device includes a processor, the processor is coupled to a memory, at least one computer program is stored in the memory, and the at least one computer program is loaded and executed by the processor so that the electronic device implements a fracture toughness testing method as described in any one of claims 1 to 4.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores at least one computer program, and the at least one computer program is loaded and executed by a processor so that a computer implements a fracture toughness testing method according to any one of claims 1 to 4.

Images