Method, device, electronic equipment and medium for detecting maximum principal strain of sample crack

Abstract

The present invention provides a method, device, electronic device, and medium for detecting the maximum principal strain of a specimen crack, belonging to the technical field of rock mechanics strain field analysis. The method comprises: obtaining multiple photographic images of a specimen study area changing over time, collected using a three-dimensional digital image correlation method; drawing a maximum principal strain cloud map based on the multiple photographic images, and determining the location of each crack propagation region based on the maximum principal strain cloud map; selecting all nodes within a principal strain concentration region based on the location of each crack propagation region, and determining the maximum principal strain information and node time corresponding to each node within the principal strain concentration region; and determining the maximum principal strain of the specimen crack based on the maximum principal strain information and node time corresponding to each node within the principal strain concentration region. The present invention employs a calculation method for nodes within the principal strain concentration region to address the technical problem of the relatively complex crack principal strain detection methods of existing methods.

Description

Technical Field

[0001] The present invention relates to the technical field of rock mechanics strain field analysis, and in particular to a method, device, electronic equipment and medium for detecting the maximum principal strain of a sample crack. Background Art

[0002] By studying the relevant failure characteristics of rock samples under indoor rock mechanics tests, it can provide certain reference value for mine safety mining design and evaluation. The initiation and expansion of microcracks is one of the main causes of rock instability and failure. Therefore, it is necessary to conduct an in-depth study of the expansion process of sample cracks during the experiment.

[0003] During the experiment, there is a good correspondence between the expansion of the crack and the concentration of the principal strain, so the study of crack expansion can be achieved by detecting the principal strain of the crack. This process inevitably involves the application of some optical measurement methods.

[0004] Existing methods for detecting crack principal strain typically obtain a specimen principal strain contour map and then post-process the image using mathematical statistics or auxiliary software to determine the crack principal strain. While these methods yield relatively accurate and continuous crack principal strain values, they often involve complex mathematical calculations or require additional software for post-processing, making the maximum crack principal strain detection process more complex. Summary of the Invention

[0005] In view of this, it is necessary to provide a method, device, electronic equipment and medium for detecting the maximum principal strain of a specimen crack, so as to solve the technical problem that the existing method for detecting the principal strain of a crack is relatively complex.

[0006] In order to solve the above problems, the present invention provides a method for detecting the maximum principal strain of a crack in a specimen, comprising:

[0007] Acquire multiple photographic images of the sample study area over time based on three-dimensional digital image correlation;

[0008] Drawing a maximum principal strain nephogram based on the plurality of photographic images, and determining the position of each crack propagation region based on the maximum principal strain nephogram;

[0009] Based on the location of each crack propagation area, all nodes in the principal strain concentration area are selected, and the maximum principal strain information and node time corresponding to each node in the principal strain concentration area are determined;

[0010] The maximum principal strain of the specimen crack is determined based on the maximum principal strain information and node time corresponding to each node in the principal strain concentration area.

[0011] In a possible implementation, drawing a maximum principal strain cloud map based on the multiple photographic images includes:

[0012] After dividing the sample research area of ​​the plurality of photographic images into speckle domains and creating seed points, a maximum principal strain cloud map is drawn for the photographic images according to a three-dimensional digital image correlation method.

[0013] In one possible implementation, determining the location of each crack propagation region based on the maximum principal strain contour includes:

[0014] In the maximum principal strain cloud map, cracks in the same strain concentration region are regarded as a main crack, and crack extension regions are searched to obtain the positions of the respective crack extension regions.

[0015] In one possible implementation, the maximum principal strain of the specimen crack is determined based on the maximum principal strain information and the node time corresponding to each node in the principal strain concentration region, including:

[0016] Calculating an average value of the maximum principal strain information corresponding to each node in the principal strain concentration region, and determining the average value as the maximum principal strain in the crack propagation region;

[0017] Based on the maximum principal strain in the crack propagation area and the node time, a characteristic curve of the evolution of the maximum principal strain of the crack with time during the test is drawn, and the maximum principal strain of the sample crack is determined based on the characteristic curve of the evolution process.

[0018] In a possible implementation, calculating an average value of maximum principal strain information corresponding to each node in the principal strain concentration region and determining the average value as the maximum principal strain in the crack propagation region includes:

[0019] After removing abnormal nodes in the principal strain concentration region, the maximum principal strain information corresponding to each remaining node in the principal strain concentration region is averaged, and the average value is determined as the maximum principal strain in the crack propagation region.

[0020] In a possible implementation, the node time corresponding to each node in the principal strain concentration region is determined based on an acquisition rate of the photographic image and a number of acquisition times of the photographic image.

[0021] In a possible implementation, the node time corresponding to each node in the strain concentration area is obtained by dividing the number of times the photographic images are collected by the acquisition rate of the photographic images.

[0022] On the other hand, the present invention also provides a device for detecting the maximum principal strain of a crack in a specimen, comprising:

[0023] An acquisition module, used to acquire multiple photographic images of the sample study area changing over time based on a three-dimensional digital image correlation method;

[0024] a position determination module, configured to draw a maximum principal strain nephogram based on the plurality of photographic images, and determine the position of each crack propagation region based on the maximum principal strain nephogram;

[0025] A node determination module is used to select all nodes in the principal strain concentration area based on the location of each crack propagation area, and determine the maximum principal strain information and node time corresponding to each node in the principal strain concentration area;

[0026] The principal strain calculation module is used to determine the maximum principal strain of the specimen crack based on the maximum principal strain information and node time corresponding to each node in the principal strain concentration area.

[0027] On the other hand, the present invention also provides an electronic device, comprising a memory and a processor, wherein:

[0028] The memory is used to store programs;

[0029] The processor is coupled to the memory and is used to execute the program stored in the memory to implement the steps of the method for detecting the maximum principal strain of a crack in a specimen as described in any one of the above.

[0030] On the other hand, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method for detecting the maximum principal strain of a specimen crack as described in any one of the above.

[0031] The beneficial effects of adopting the above-mentioned implementation method are as follows: the maximum principal strain detection method, device, electronic device and medium of the specimen crack provided by the present invention use multiple photographic images of the specimen study area changing over time collected by the three-dimensional digital image correlation method to draw a maximum principal strain cloud map, thereby determining the position of each crack extension area. Based on the position of each crack extension area, all node data in the principal strain concentration area are selected for simple mathematical calculations to obtain the maximum principal strain of the crack. The present invention does not require post-processing of the entire photographic image according to mathematical statistical methods or some auxiliary software. It only needs to find the position of the crack extension area from the maximum principal strain cloud map and select the nodes in the principal strain concentration area for calculation. The calculation method of the nodes in the principal strain concentration area uses less calculation amount than that of performing calculations on the entire photographic image, thereby reducing the complexity of the crack principal strain detection method. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0033] Figure 1 A flow chart of an embodiment of a method for detecting the maximum principal strain of a crack in a specimen provided by the present invention;

[0034] Figure 2 A schematic diagram of the expansion area of ​​the main crack provided by the present invention;

[0035] Figure 3 A schematic diagram of nodes within the principal strain concentration area provided by the present invention;

[0036] Figure 4 A schematic diagram of the derived node information provided by the present invention;

[0037] Figure 5 A schematic diagram of the dynamic evolution process of the maximum principal strain of a crack provided by the present invention;

[0038] Figure 6 Schematic diagram of the image acquisition device provided by the present invention;

[0039] Figure 7 A flow chart of another embodiment of the method for detecting the maximum principal strain of a crack in a specimen provided by the present invention;

[0040] Figure 8 A flow chart for searching for the location of each crack extension area provided by the present invention;

[0041] Figure 9 A principle block diagram of an embodiment of a device for detecting the maximum principal strain of a specimen crack provided by the present invention;

[0042] Figure 10 This is a schematic structural diagram of an embodiment of the electronic device provided by the present invention. DETAILED DESCRIPTION

[0043] The following will provide a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0044] In the description of the embodiments of the present application, unless otherwise specified, “a plurality of” means two or more.

[0045] The terms "including" and "having" and any variations thereof in the embodiments of the present invention are intended to cover non-exclusive inclusions. For example, a process, method, apparatus, product or device comprising a series of steps or modules is not necessarily limited to those steps or modules explicitly listed, but may include other steps or modules not explicitly listed or inherent to these processes, methods, products or devices.

[0046] The naming or numbering of the steps in the embodiments of the present invention does not mean that the steps in the method flow must be executed in the time / logical sequence indicated by the naming or numbering. The execution order of the named or numbered process steps can be changed according to the technical purpose to be achieved, as long as the same or similar technical effects can be achieved.

[0047] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present invention. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute a separate or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0048] The present invention provides a method, device, electronic equipment and medium for detecting the maximum principal strain of a specimen crack, which are described below respectively.

[0049] like Figure 1 As shown, the present invention provides a method for detecting the maximum principal strain of a crack in a specimen, comprising:

[0050] S101, acquiring multiple photographic images of the sample study area changing over time based on a three-dimensional digital image correlation method;

[0051] S102, drawing a maximum principal strain nephogram based on the plurality of photographic images, and determining the position of each crack propagation region based on the maximum principal strain nephogram;

[0052] S103, based on the position of each crack extension area, selecting all nodes in the principal strain concentration area, and determining the maximum principal strain information and node time corresponding to each node in the principal strain concentration area;

[0053] S104 , determining the maximum principal strain of the crack of the specimen based on the maximum principal strain information and the node time corresponding to each node in the principal strain concentration area.

[0054] It can be understood that the method for detecting the maximum principal strain of a sample crack provided by the present invention can obtain the evolution process of the maximum principal strain of the sample crack over time while being fast, simple, direct, accurate, and highly applicable.

[0055] The present invention provides a method for detecting the maximum principal strain of a sample crack, comprising the following steps:

[0056] Using 3D-DIC (three-dimensional digital image correlation) technology, a series of high-definition photographic images of the specimen's study area changing over time during the experiment are obtained. The series of images obtained using 3D-DIC technology are discontinuous in time, and the camera acquisition frame rate is adjusted in a timely manner based on the experiment duration and crack growth rate.

[0057] Based on the high-definition photographic images of the specimen study area, the maximum principal strain cloud map is drawn to search for the location of each crack propagation area;

[0058] Based on the location of the crack propagation area, all nodes in the principal strain concentration area are selected, and the time and maximum principal strain information of each node are derived;

[0059] Based on the derived node information, the average maximum principal strain of all nodes in the crack propagation area is taken as the maximum principal strain of the crack. The evolution of the maximum principal strain of the crack with time during the experiment is plotted to realize the detection of the maximum principal strain of the specimen crack.

[0060] In some embodiments, drawing a maximum principal strain cloud map based on the plurality of photographic images includes:

[0061] After dividing the sample research area of ​​the plurality of photographic images into speckle domains and creating seed points, a maximum principal strain cloud map is drawn for the photographic images according to a three-dimensional digital image correlation method.

[0062] It can be understood that the speckle domain is divided in the specimen study area, seed points are created, and the maximum principal strain cloud map is drawn for each collected image based on the 3D-DIC image recognition technology.

[0063] In some embodiments, determining the location of each crack propagation region based on the maximum principal strain contour includes:

[0064] In the maximum principal strain cloud map, cracks in the same strain concentration region are regarded as a main crack, and crack extension regions are searched to obtain the positions of the respective crack extension regions.

[0065] It can be understood that there is a good correspondence between the principal strain concentration area and the crack extension of the specimen. In the final image collected in which the principal strain cloud map can be clearly identified, the cracks in the same strain concentration area are regarded as a main crack, and the crack extension area is searched according to this method.

[0066] For example, by analyzing the maximum principal strain cloud map of the study area on the surface of the sandstone specimen, the extension areas of two main cracks were found, such as Figure 2 As shown, it includes main crack 1 and main crack 2.

[0067] The corresponding positions of the main strain concentration areas in the main crack 1 and main crack 2 extension areas of the specimen are as follows: Figure 2 As shown in FIG, it includes the main strain concentration area 1' and the main strain concentration area 2'. Specifically, taking the main strain concentration area 1' as an example, as shown in FIG. Figure 3 As shown in Figure 1, all nodes 1-19 in the principal strain concentration area 1' are selected, totaling 19 nodes, and then the stage and maximum principal strain information of each node are derived. Taking node 1 as an example, the derived node information is as follows: Figure 4 As shown in Figure 3, each node corresponds to 802 stages, that is, 802 digital images were collected during the experiment.

[0068] In some embodiments, determining the maximum principal strain of the crack of the specimen based on the maximum principal strain information and the node time corresponding to each node in the principal strain concentration region includes:

[0069] Calculating an average value of the maximum principal strain information corresponding to each node in the principal strain concentration region, and determining the average value as the maximum principal strain in the crack propagation region;

[0070] Based on the maximum principal strain in the crack propagation area and the node time, a characteristic curve of the evolution of the maximum principal strain of the crack with time during the test is drawn, and the maximum principal strain of the sample crack is determined based on the characteristic curve of the evolution process.

[0071] It can be understood that based on the derived information of each node, the average value of the maximum principal strain of all nodes in the crack propagation area is used as the maximum principal strain of the crack, and the evolution process of the maximum principal strain of the crack with time during the experiment is plotted to realize the detection of the maximum principal strain of the specimen crack.

[0072] The characteristic curve of the evolution of the maximum principal strain of the crack with time during the experiment is obtained by plotting the characteristic curve with the experimental time and the maximum principal strain of the crack corresponding to each time as the horizontal axis and the vertical axis respectively.

[0073] For example, the information derived from all nodes in the principal strain concentration region 1' and the principal strain concentration region 2' is processed, and the node time t determined by the acquisition rate v and the stage number n is in the range of 0 to 401 s. After removing the nodes with abnormal data, the average value of the maximum principal strain of the remaining nodes in each principal strain concentration region is used as the crack principal strain, as shown in the following example: Figure 5 As shown in the figure, a curve graph is drawn with the experimental time and the maximum principal strain of the crack corresponding to each time as the horizontal axis and the vertical axis respectively, and the dynamic evolution process of the maximum principal strain of the crack with the experimental time during the experiment is obtained.

[0074] In some embodiments, the node time corresponding to each node in the principal strain concentration region is determined based on the acquisition rate of the photographic image and the number of acquisition times of the photographic image.

[0075] Furthermore, the node time corresponding to each node in the strain concentration area is obtained by dividing the number of acquisition times of the photographic images by the acquisition rate of the photographic images.

[0076] It can be understood that the node time determination method is: in 3D-DIC, one stage is added for each acquisition, that is, stage=n represents the nth image acquired, and the node time information t=n / v is determined according to the acquisition rate v and the number of stages n.

[0077] Specifically, taking a standard cylindrical sandstone specimen with dimensions of ϕ 50 mm × 100 mm under uniaxial compression as an example, scattered spots were first sprayed on the study area of ​​the specimen. Then, a DIC image acquisition device was installed to take real-time photos of the study area on the specimen surface under uniaxial compression to collect image information. Figure 6 This is the principle diagram of the image acquisition device of the present invention. During the experiment, the camera acquisition rate t was set to 2 frames / s, and a series of high-definition camera images of the study area on the surface of the sandstone sample changing with time were obtained during the experiment.

[0078] In some embodiments, averaging the maximum principal strain information corresponding to each node in the principal strain concentration region and determining the average value as the maximum principal strain in the crack propagation region includes:

[0079] After removing abnormal nodes in the principal strain concentration region, the maximum principal strain information corresponding to each remaining node in the principal strain concentration region is averaged, and the average value is determined as the maximum principal strain in the crack propagation region.

[0080] In some embodiments, as Figure 7 As shown, a method for detecting the maximum principal strain of a sample crack based on 3D-DIC according to the present invention includes the following steps:

[0081] Step 1: Using 3D-DIC technology, obtain a series of high-definition photographic images of the specimen study area over time during the experiment;

[0082] Step 2: Based on the high-definition photographic image of the specimen study area, a maximum principal strain cloud map is drawn to search for the location of each crack propagation area;

[0083] Step 3: Based on the location of the crack propagation area, select all nodes in the principal strain concentration area and derive the time and maximum principal strain information of each node;

[0084] Step 4: Based on the derived node information, the average maximum principal strain of all nodes in the crack propagation area is used as the maximum principal strain of the crack. The evolution of the maximum principal strain of the crack with time during the experiment is plotted to realize the maximum principal strain detection of the specimen crack.

[0085] Furthermore, in step 1, the series of images obtained based on the 3D-DIC technology are discontinuous in time, and the number of camera acquisition frames is adjusted in time according to the experiment duration and the crack growth rate.

[0086] Furthermore, the step 2 specifically includes the following steps:

[0087] Step 2.1: Divide the speckle domain in the specimen study area, create seed points, and draw a maximum principal strain contour map for each collected image based on 3D-DIC image recognition technology;

[0088] Step 2.2: The principal strain concentration region has a good correspondence with the specimen crack propagation. In the final image collected where the principal strain contour can be clearly identified, the cracks in the same strain concentration region are considered as a main crack, and the crack propagation region is searched based on this method.

[0089] Furthermore, in step 3, the node time is determined by adding one stage for each acquisition in 3D-DIC, i.e., stage=n represents the nth image acquired, and the node time information t=n / v is determined according to the acquisition rate v and the number of stages n.

[0090] Furthermore, in step 4, the evolution of the maximum principal strain of the crack with time during the experiment is obtained by drawing a characteristic curve with the experimental time and the maximum principal strain of the crack corresponding to each time as the horizontal axis and the vertical axis respectively.

[0091] Specifically, taking a standard cylindrical sandstone specimen with dimensions of ϕ 50 mm × 100 mm under uniaxial compression as an example, scattered spots were first sprayed on the study area of ​​the specimen. Then, a DIC image acquisition device was installed to take real-time photos of the study area on the specimen surface under uniaxial compression to collect image information. Figure 6 This is the principle diagram of the image acquisition device of the present invention. During the experiment, the camera acquisition rate t was set to 2 frames / s, and a series of high-definition camera images of the study area on the surface of the sandstone sample changing with time were obtained during the experiment.

[0092] It is understandable that if Figure 8 As shown, the step 2 specifically includes the following steps:

[0093] Step 2.1: Divide the speckle domain in the study area of ​​the collected sandstone sample image surface, create seed points, and then draw the maximum principal strain contour map for each collected image based on 3D-DIC image recognition technology;

[0094] Step 2.2: Cracks in the same strain concentration area are considered as a main crack, and this method is used to search for the crack extension range in the study area on the surface of the sandstone specimen.

[0095] Specifically, in step 2.2, by analyzing the maximum principal strain cloud map of the study area on the surface of the sandstone specimen, the extension areas of two main cracks are found, such as Figure 2 As shown, it includes main crack 1 and main crack 2.

[0096] It can be understood that in step 3, the corresponding positions of the main strain concentration areas in the extension areas of the main cracks 1 and 2 of the specimen are as follows: Figure 2 As shown in FIG, it includes the main strain concentration area 1' and the main strain concentration area 2'. Specifically, taking the main strain concentration area 1' as an example, as shown in FIG. Figure 3 As shown in Figure 1, all nodes 1-19 in the principal strain concentration area 1' are selected, totaling 19 nodes, and then the stage and maximum principal strain information of each node are derived. Taking node 1 as an example, the derived node information is as follows: Figure 4 As shown in Figure 3, each node corresponds to 802 stages, that is, 802 digital images were collected during the experiment.

[0097] It is understood that in step 4, the information derived from all nodes in the principal strain concentration region 1' and the principal strain concentration region 2' is processed, and the node time t determined by the acquisition rate v and the stage number n is within the range of 0 to 401 s. After removing the nodes with abnormal data, the average value of the maximum principal strain of the remaining nodes in each principal strain concentration region is used as the crack principal strain, as shown in Figure 5 As shown in the figure, a curve graph is drawn with the experimental time and the maximum principal strain of the crack corresponding to each time as the horizontal axis and the vertical axis respectively, and the dynamic evolution process of the maximum principal strain of the crack with the experimental time during the experiment is obtained.

[0098] In summary, the present invention provides a method for detecting the maximum principal strain of a specimen crack, comprising: acquiring multiple photographic images of a specimen study area changing with time, collected based on a three-dimensional digital image correlation method; drawing a maximum principal strain cloud map based on the multiple photographic images, and determining the position of each crack extension area based on the maximum principal strain cloud map; selecting all nodes in a principal strain concentration area based on the position of each crack extension area, and determining the maximum principal strain information and node time corresponding to each node in the principal strain concentration area; and determining the maximum principal strain of the specimen crack based on the maximum principal strain information and node time corresponding to each node in the principal strain concentration area.

[0099] The present invention provides a method for detecting the maximum principal strain of a specimen crack. Multiple photographic images of a specimen study area changing over time are collected using a three-dimensional digital image correlation method, and a maximum principal strain cloud map is drawn to further determine the position of each crack extension area. Based on the position of each crack extension area, all node data within the principal strain concentration area are selected for simple mathematical calculations to obtain the maximum principal strain of the crack. The present invention does not require post-processing of the entire photographic image using mathematical statistical methods or auxiliary software. Instead, the method only requires finding the position of the crack extension area from the maximum principal strain cloud map and performing calculations on the nodes within the principal strain concentration area. Using the calculation method of the nodes within the principal strain concentration area reduces the amount of computation compared to performing calculations on the entire photographic image, thereby reducing the complexity of the method for detecting the principal strain of the crack.

[0100] The beneficial effects of adopting the above detection method are:

[0101] 1. The present invention provides a method for detecting the maximum principal strain of a specimen crack based on 3D-DIC. This method is based on DIC technology and obtains the maximum principal strain of the crack by performing simple mathematical calculations on the node data within the study area. The calculation method is simple and fast.

[0102] 2. Compared with monocular data acquisition equipment, binocular 3D-DIC technology can obtain three-dimensional spatial data information of nodes within the crack propagation area through image matching. Therefore, this method can be extended to multiple fields and has better universality.

[0103] 3. The acquisition rate can be adjusted according to different experimental conditions, and the dynamic evolution process of the crack principal strain with the experimental time can be approximately obtained. This method is easy to understand, and the final crack evolution results are intuitive and reliable.

[0104] like Figure 9 As shown, the present invention also provides a device 900 for detecting the maximum principal strain of a crack in a specimen, comprising:

[0105] An acquisition module 901 is used to acquire multiple photographic images of a sample study area changing over time, collected using a three-dimensional digital image correlation method;

[0106] a position determination module 902 for drawing a maximum principal strain nephogram based on the plurality of photographic images, and determining the position of each crack propagation region based on the maximum principal strain nephogram;

[0107] A node determination module 903 is configured to select all nodes in the principal strain concentration region based on the locations of the crack propagation regions, and determine the maximum principal strain information and node time corresponding to each node in the principal strain concentration region;

[0108] The principal strain calculation module 904 is used to determine the maximum principal strain of the sample crack based on the maximum principal strain information and node time corresponding to each node in the principal strain concentration area.

[0109] The device for detecting the maximum principal strain of a crack in a specimen provided in the above embodiment can implement the technical solution described in the embodiment of the method for detecting the maximum principal strain of a crack in a specimen. The specific implementation principles of the above modules or units can be found in the corresponding contents of the embodiment of the method for detecting the maximum principal strain of a crack in a specimen, and will not be repeated here.

[0110] like Figure 10 As shown, the present invention also provides an electronic device 1000. The electronic device 1000 includes a processor 1001, a memory 1002 and a display 1003. Figure 10 Only some of the components of the electronic device 1000 are shown, but it should be understood that it is not required to implement all of the shown components, and more or fewer components may be implemented instead.

[0111] In some embodiments, the memory 1002 may be an internal storage unit of the electronic device 1000, such as a hard disk or memory of the electronic device 1000. In other embodiments, the memory 1002 may also be an external storage device of the electronic device 1000, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. equipped on the electronic device 1000.

[0112] Furthermore, the memory 1002 may include both an internal storage unit of the electronic device 1000 and an external storage device. The memory 1002 is used to store application software installed in the electronic device 1000 and various data.

[0113] In some embodiments, the processor 1001 may be a central processing unit (CPU), a microprocessor, or other data processing chip, configured to execute program codes or process data stored in the memory 1002, such as the method for detecting the maximum principal strain of a specimen crack in the present invention.

[0114] In some embodiments, display 1003 can be an LED display, a liquid crystal display, a touch-sensitive liquid crystal display, or an OLED (Organic Light-Emitting Diode) touchscreen. Display 1003 is used to display information on electronic device 1000 and to display a visual user interface. Components 1001-1003 of electronic device 1000 communicate with each other via a system bus.

[0115] In some embodiments of the present invention, when the processor 1001 executes the sample crack maximum principal strain detection program in the memory 1002, the following steps may be implemented:

[0116] Acquire multiple photographic images of the sample study area over time based on three-dimensional digital image correlation;

[0117] Drawing a maximum principal strain nephogram based on the plurality of photographic images, and determining the position of each crack propagation region based on the maximum principal strain nephogram;

[0118] Based on the location of each crack propagation area, all nodes in the principal strain concentration area are selected, and the maximum principal strain information and node time corresponding to each node in the principal strain concentration area are determined;

[0119] The maximum principal strain of the specimen crack is determined based on the maximum principal strain information and node time corresponding to each node in the principal strain concentration area.

[0120] It should be understood that, when the processor 1001 executes the sample crack maximum principal strain detection program in the memory 1002 , in addition to the above functions, it can also implement other functions. For details, please refer to the description of the corresponding method embodiment above.

[0121] Furthermore, the embodiments of the present invention do not specifically limit the type of electronic device 1000 mentioned. The electronic device 1000 may be a portable electronic device such as a mobile phone, tablet computer, personal digital assistant (PDA), wearable device, or laptop computer. Exemplary embodiments of portable electronic devices include, but are not limited to, portable electronic devices running iOS, Android, Microsoft, or other operating systems. The portable electronic devices mentioned above may also be other portable electronic devices, such as a laptop computer with a touch-sensitive surface (e.g., a touch panel). It should also be understood that in some other embodiments of the present invention, the electronic device 1000 may not be a portable electronic device, but rather a desktop computer with a touch-sensitive surface (e.g., a touch panel).

[0122] In another aspect, the present invention further provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method for detecting the maximum principal strain of a crack in a specimen provided by the above methods, the method comprising:

[0123] Acquire multiple photographic images of the sample study area over time based on three-dimensional digital image correlation;

[0124] Drawing a maximum principal strain nephogram based on the plurality of photographic images, and determining the position of each crack propagation region based on the maximum principal strain nephogram;

[0125] Based on the location of each crack propagation area, all nodes in the principal strain concentration area are selected, and the maximum principal strain information and node time corresponding to each node in the principal strain concentration area are determined;

[0126] The maximum principal strain of the specimen crack is determined based on the maximum principal strain information and node time corresponding to each node in the principal strain concentration area.

[0127] Those skilled in the art will appreciate that all or part of the process steps of the above-described embodiments can be implemented by instructing related hardware through a computer program, and the program can be stored in a computer-readable storage medium, such as a magnetic disk, an optical disk, a read-only memory, or a random access memory.

[0128] The above is a detailed introduction to the method, device, electronic equipment and medium for detecting the maximum principal strain of a specimen crack provided by the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the ideas of the present invention, there may be changes in the specific implementation methods and application scopes. In summary, the contents of this specification should not be understood as limiting the present invention.

Claims

1. A method for detecting the maximum principal strain of a specimen crack, characterized in that: include: Acquire multiple photographic images of the sample study area over time based on three-dimensional digital image correlation; Drawing a maximum principal strain nephogram based on the plurality of photographic images, and determining the position of each crack propagation region based on the maximum principal strain nephogram; Based on the location of each crack propagation area, all nodes in the principal strain concentration area are selected, and the maximum principal strain information and node time corresponding to each node in the principal strain concentration area are determined; Based on the maximum principal strain information and node time corresponding to each node in the principal strain concentration area, the maximum principal strain of the specimen crack is determined; Based on the maximum principal strain information and node time corresponding to each node in the principal strain concentration area, the maximum principal strain of the specimen crack is determined, including: Calculating an average value of the maximum principal strain information corresponding to each node in the principal strain concentration region, and determining the average value as the maximum principal strain in the crack propagation region; Based on the maximum principal strain in the crack propagation area and the node time, a characteristic curve of the evolution of the maximum principal strain of the crack with time during the test is drawn, and the maximum principal strain of the sample crack is determined based on the characteristic curve of the evolution process.

2. The method for detecting the maximum principal strain of a crack in a specimen according to claim 1, wherein: Based on the plurality of photographic images, a maximum principal strain cloud map is drawn, including: After dividing the sample research area of ​​the plurality of photographic images into speckle domains and creating seed points, a maximum principal strain cloud map is drawn for the photographic images according to a three-dimensional digital image correlation method.

3. The method for detecting the maximum principal strain of a crack in a specimen according to claim 1, wherein: Based on the maximum principal strain cloud map, the location of each crack propagation area is determined, including: In the maximum principal strain cloud map, cracks in the same strain concentration region are regarded as a main crack, and crack extension regions are searched to obtain the positions of the respective crack extension regions.

4. The method for detecting the maximum principal strain of a crack in a specimen according to claim 1, wherein: Calculating an average value of the maximum principal strain information corresponding to each node in the principal strain concentration region, and determining the average value as the maximum principal strain in the crack propagation region, including: After removing abnormal nodes in the principal strain concentration region, the maximum principal strain information corresponding to each remaining node in the principal strain concentration region is averaged, and the average value is determined as the maximum principal strain in the crack propagation region.

5. The method for detecting the maximum principal strain of a crack in a specimen according to claim 1, wherein: The node time corresponding to each node in the principal strain concentration region is determined based on the acquisition rate of the photographic image and the number of acquisition times of the photographic image.

6. The method for detecting the maximum principal strain of a crack in a specimen according to claim 5, wherein: The node time corresponding to each node in the strain concentration area is obtained by dividing the number of acquisitions of the photographic image by the acquisition rate of the photographic image.

7. A device for detecting the maximum principal strain of a specimen crack, characterized in that: include: An acquisition module, used to acquire multiple photographic images of the sample study area changing over time based on a three-dimensional digital image correlation method; a position determination module, configured to draw a maximum principal strain nephogram based on the plurality of photographic images, and determine the position of each crack propagation region based on the maximum principal strain nephogram; A node determination module is used to select all nodes in the principal strain concentration area based on the location of each crack propagation area, and determine the maximum principal strain information and node time corresponding to each node in the principal strain concentration area; A principal strain calculation module is used to determine the maximum principal strain of the specimen crack based on the maximum principal strain information and node time corresponding to each node in the principal strain concentration area; Based on the maximum principal strain information and node time corresponding to each node in the principal strain concentration area, the maximum principal strain of the specimen crack is determined, including: Calculating an average value of the maximum principal strain information corresponding to each node in the principal strain concentration region, and determining the average value as the maximum principal strain in the crack propagation region; Based on the maximum principal strain in the crack propagation area and the node time, a characteristic curve of the evolution of the maximum principal strain of the crack with time during the test is drawn, and the maximum principal strain of the sample crack is determined based on the characteristic curve of the evolution process.

8. An electronic device, characterized in that: comprising a memory and a processor, wherein, The memory is used to store programs; The processor is coupled to the memory and is configured to execute the program stored in the memory to implement the steps of the method for detecting the maximum principal strain of a specimen crack as claimed in any one of claims 1 to 6.

9. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method for detecting the maximum principal strain of a specimen crack are implemented as claimed in any one of claims 1 to 6.

Images