CN112903443A - Method and device for determining propagation speed of fracture process zone of rock material crack tip - Google Patents
Method and device for determining propagation speed of fracture process zone of rock material crack tip Download PDFInfo
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- CN112903443A CN112903443A CN202110121916.2A CN202110121916A CN112903443A CN 112903443 A CN112903443 A CN 112903443A CN 202110121916 A CN202110121916 A CN 202110121916A CN 112903443 A CN112903443 A CN 112903443A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/08—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/02—Details
- G01N3/06—Special adaptations of indicating or recording means
- G01N3/068—Special adaptations of indicating or recording means with optical indicating or recording means
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0001—Type of application of the stress
- G01N2203/0003—Steady
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0014—Type of force applied
- G01N2203/0016—Tensile or compressive
- G01N2203/0019—Compressive
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0058—Kind of property studied
- G01N2203/006—Crack, flaws, fracture or rupture
- G01N2203/0062—Crack or flaws
- G01N2203/0066—Propagation of crack
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0058—Kind of property studied
- G01N2203/006—Crack, flaws, fracture or rupture
- G01N2203/0067—Fracture or rupture
Abstract
The invention provides a method and equipment for determining the propagation speed of a fracture process zone of a rock material crack tip. The method comprises the following steps: loading a test-grade rock sample, acquiring a plurality of pictures according to time intervals, and obtaining full-field displacement distribution of the surface of the test-grade rock sample according to the pictures; arranging a plurality of virtual displacement meters on a discontinuous line of the crack tip at a distance, and obtaining an opening displacement set of the crack tip at different loading moments according to time intervals; in the curve inflection point region of each expansion displacement in the expansion displacement set, connecting points on the curve corresponding to the end points of the curve slope threshold range to obtain a reference straight line of each expansion displacement, and acquiring the corresponding duration of the maximum value of the difference value between the curve and the reference straight line in the vertical direction; and obtaining the propagation speed of the crack tip fracture process area corresponding to each opening displacement according to a distance and corresponding duration. The method can realize the quantitative analysis of the evolution and propagation of the fracture process zone of the crack tip.
Description
Technical Field
The embodiment of the invention relates to the technical field of rock fracture mechanics, in particular to a method and equipment for determining the propagation speed of a fracture process area of a rock material crack tip.
Background
In the field of rock mechanics, the rock material has the phenomena of crack initiation and propagation under the action of external force load. When the damage caused by the internal fracture of the material is accumulated to a certain degree, the material fails, and even further engineering accidents occur, so that the research and the understanding of the fracture rule of the internal crack of the material have very important significance for the construction of engineering. At present, research on fracture process zones is mainly focused on theoretical analysis, related tests and identification and characterization research on fracture process zones in the test process are few, and particularly quantitative research on evolution and propagation of fracture process zones related to time is rare. Therefore, it is an urgent technical problem in the art to develop a method and apparatus for determining the propagation velocity of the fracture process zone of the crack tip of the rock material, so as to perform quantitative analysis on the evolution and propagation of the fracture process zone of the crack tip.
Disclosure of Invention
In view of the above problems in the prior art, embodiments of the present invention provide a method and an apparatus for determining a propagation velocity of a fracture process zone at a crack tip of a rock material.
In a first aspect, embodiments of the present invention provide a method of determining a propagation velocity of a fracture process zone at a crack tip of a rock material, comprising: loading a test-grade rock sample, acquiring a plurality of pictures according to time intervals, and obtaining full-field displacement distribution of the surface of the test-grade rock sample according to the pictures; arranging a plurality of virtual displacement meters on a discontinuous line of the crack tip at a distance, and obtaining an opening displacement set of the crack tip at different loading moments according to the time intervals; in the curve inflection point region of each expansion displacement in the expansion displacement set, connecting points on the curve corresponding to the end points of the curve slope threshold range to obtain a reference straight line of each expansion displacement, and acquiring the corresponding duration of the maximum value of the difference value between the curve and the reference straight line in the vertical direction; and obtaining the propagation speed of the crack tip fracture process area corresponding to each opening displacement according to the distance and the corresponding duration.
Based on the content of the above method embodiments, the method for determining the propagation velocity of the fracture process zone of the rock material crack tip provided in the embodiments of the present invention includes that the full-field displacement distribution of the surface of the test-grade rock sample includes:
wherein u isi,xAnd ui,yRespectively displacement of the ith point in the picture along the x direction and the y direction; u. of0And v0Displacement along the x direction and the y direction at the central point respectively; (x)0,y0) And (x)i,yi) Respectively a coordinate at the central point and a coordinate at the ith point; the partial derivative of u or v with respect to the coordinate x or y is the gradient of the displacement along the x-axis or y-axis.
On the basis of the content of the above method embodiment, the method for determining the propagation velocity of the fracture process zone of the rock material crack tip provided in the embodiment of the present invention includes:
t＝n×Δt
wherein t is the loading time; n is the number of the plurality of virtual displacement meters; Δ t is the duration interval.
Based on the above disclosure of the method embodiments, the method for determining the propagation velocity of the fracture process zone of the crack tip of the rock material provided in the embodiments of the present invention, where the slope threshold is in a range from 0 to 0.95, correspondingly, connecting points on the curve corresponding to the end points of the slope threshold of the curve to obtain the reference line for each opening displacement, includes: and connecting the point with the slope of 0 with the point with the slope of 0.95 on the curve to obtain a reference straight line of each opening displacement.
On the basis of the content of the above method embodiment, the method for determining the propagation velocity of the fracture process zone of the crack tip of the rock material, provided in the embodiment of the present invention, obtaining the propagation velocity of the fracture process zone of the crack tip corresponding to each opening displacement according to the distance and the corresponding time length includes:
wherein v isi+1The propagation speed of a crack tip fracture process area between the ith virtual displacement meter and the (i + 1) th virtual displacement meter is measured; u is the distance; t is ti+1And tiThe time length of the fracture process zone reaching the (i + 1) th and the (i) th virtual displacement meters is shown.
Based on the above disclosure of the method embodiments, the method for determining the propagation velocity of the rock material crack tip fracture process zone provided in the embodiments of the present invention further includes, before the loading the test-grade rock sample: drilling and cutting a rock material to prepare a Brazilian disc-shaped rock sample, and blackening and whitening the Brazilian disc-shaped rock sample to obtain the test-grade rock sample.
On the basis of the content of the above method embodiments, the method for determining the propagation velocity of the fracture process zone at the crack tip of the rock material provided in the embodiment of the present invention, wherein the blackening and whitening of the brazilian disc-shaped rock sample, includes: and uniformly spraying white matte paint on the surface of the Brazilian disc-shaped rock sample, and after the white matte paint is solidified, randomly spraying black matte paint on the upper part of the white matte paint to form black and white speckles.
In a second aspect, embodiments of the present invention provide an apparatus for determining a propagation velocity of a fracture process zone at a crack tip of a rock material, comprising:
the full-field displacement distribution module is used for loading the test-grade rock sample, acquiring a plurality of pictures according to the time interval, and acquiring the full-field displacement distribution of the surface of the test-grade rock sample according to the pictures; the virtual displacement meter module is used for distributing a plurality of virtual displacement meters at a distance on a discontinuous line of the crack tip and obtaining an opening displacement set of the crack tip at different loading moments according to the time intervals; a difference module, configured to connect, in a curve inflection point region of each opening displacement in the opening displacement set, points on the curve corresponding to an end point of a curve slope threshold range to obtain a reference line of each opening displacement, and obtain a corresponding duration of a maximum value of a difference between the curve and the reference line in a vertical direction; and the propagation speed module is used for obtaining the propagation speed of the crack tip fracture process area corresponding to each opening displacement according to the distance and the corresponding duration.
In a third aspect, an embodiment of the present invention provides an electronic device, including:
at least one processor; and
at least one memory communicatively coupled to the processor, wherein:
the memory stores program instructions executable by the processor, the processor invoking the program instructions to perform a method of determining a propagation velocity of a fracture process zone of a crack tip of a rock material provided by any of the various implementations of the first aspect.
In a fourth aspect, embodiments of the present invention provide a non-transitory computer readable storage medium storing computer instructions for causing a computer to perform a method of determining propagation velocity of a fracture process zone at a crack material crack tip as provided in any of the various implementations of the first aspect.
According to the method and the device for determining the propagation speed of the fracture process area of the crack tip of the rock material, provided by the embodiment of the invention, the propagation speed of the fracture process area of the crack tip can be finally obtained by obtaining the full-field displacement distribution of the surface of a test-grade rock sample, distributing a plurality of virtual displacement meters on a discontinuous line of the crack tip, obtaining opening displacement sets at different loading moments and corresponding duration of a reference straight line of each opening displacement and a maximum value of a curve difference value, and realizing the quantitative analysis of the evolution and propagation of the fracture process area of the crack tip.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, a brief description will be given below to the drawings required for the description of the embodiments or the prior art, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
FIG. 1 is a flow chart of a method for determining propagation velocity of a fracture process zone of a crack tip of a rock material according to an embodiment of the invention;
FIG. 2 is a schematic structural diagram of an apparatus for determining a propagation velocity of a fracture process zone at a crack tip of a rock material according to an embodiment of the present invention;
fig. 3 is a schematic physical structure diagram of an electronic device according to an embodiment of the present invention;
fig. 4 is a schematic diagram illustrating an arrangement effect of a virtual displacement meter according to an embodiment of the present invention;
FIG. 5 is a graph of the variation of the opening displacement with the loading duration according to the embodiment of the present invention;
fig. 6 is a schematic diagram of obtaining a difference of opening displacement according to an embodiment of the present invention;
fig. 7 is a schematic diagram of obtaining a maximum value of the opening displacement difference according to an embodiment of the present invention;
FIG. 8 is a schematic diagram of the preparation of a Brazilian disc rock sample provided by an embodiment of the present invention;
fig. 9 is a schematic diagram of a test-grade rock sample preparation provided by an embodiment of the invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. In addition, technical features of various embodiments or individual embodiments provided by the present invention may be arbitrarily combined with each other to form a feasible technical solution, and such combination is not limited by the sequence of steps and/or the structural composition mode, but must be realized by a person skilled in the art, and when the technical solution combination is contradictory or cannot be realized, such a technical solution combination should not be considered to exist and is not within the protection scope of the present invention.
An embodiment of the present invention provides a method for determining a propagation velocity of a fracture process zone at a crack tip of a rock material, referring to fig. 1, the method including: loading a test-grade rock sample, acquiring a plurality of pictures according to time intervals, and obtaining full-field displacement distribution of the surface of the test-grade rock sample according to the pictures; arranging a plurality of virtual displacement meters on a discontinuous line of the crack tip at a distance, and obtaining an opening displacement set of the crack tip at different loading moments according to the time intervals; in the curve inflection point region of each expansion displacement in the expansion displacement set, connecting points on the curve corresponding to the end points of the curve slope threshold range to obtain a reference straight line of each expansion displacement, and acquiring the corresponding duration of the maximum value of the difference value between the curve and the reference straight line in the vertical direction; and obtaining the propagation speed of the crack tip fracture process area corresponding to each opening displacement according to the distance and the corresponding duration.
Based on the content of the foregoing method embodiment, as an optional embodiment, in the method for determining a propagation velocity of a fracture process zone at a crack tip of a rock material provided in an embodiment of the present invention, a full-field displacement distribution of a surface of the test-grade rock sample includes:
wherein u isi,xAnd ui,yRespectively displacement of the ith point in the picture along the x direction and the y direction; u. of0And v0Displacement along the x direction and the y direction at the central point respectively; (x)0,y0) And (x)i,yi) Respectively a coordinate at the central point and a coordinate at the ith point; the partial derivative of u or v with respect to the coordinate x or y is the gradient of the displacement along the x-axis or y-axis.
Specifically, n photos are selected from the images in the test process according to a certain time interval delta t, and the selected photos are processed by adopting a digital image correlation method, so that the change rule of the full-field displacement of the surface of the test-grade rock sample along with the loading time is obtained. In the digital image correlation method, the displacement is calculated using equation (1). And obtaining the displacement distribution of the surface of the test-grade rock sample at different moments in the whole loading process, as shown in fig. 4. When the test-grade rock sample is damaged, the displacement of the crack tip along the x direction shows a discontinuous characteristic, so that the crack tip is damaged to a certain extent, and the fracture process area also has an evolution and propagation phenomenon on the discontinuous line. In order to study and judge the propagation speed of the fracture process zone, a certain number of virtual displacement meters L are arranged on the discontinuous line at equal intervals u1To LnThe distance between the virtual displacement meters is u (i.e. the distance, i.e. the distance between any two adjacent virtual lines in fig. 4).
Based on the content of the foregoing method embodiment, as an optional embodiment, the method for determining the propagation velocity of the fracture process zone at the crack tip of the rock material provided in the embodiment of the present invention includes:
t＝n×Δt (2)
wherein t is the loading time; n is the number of the plurality of virtual displacement meters; Δ t is the duration interval.
In particular, a virtual displacement meter L is used1To LnCan obtainThe different loading time is shown as the formula (2). Opening displacement u near the tip of a crack (in another embodiment, a type I crack) in a test grade rock sample1To unThe opening displacement and the loading time period t are plotted as a curve as shown in FIG. 5 (in u)1For example) for subsequent analysis.
Based on the content of the foregoing method embodiment, as an alternative embodiment, the method for determining the propagation velocity of the fracture process zone at the crack tip of the rock material provided in the embodiment of the present invention, where the slope threshold range is 0 to 0.95, and correspondingly, the connecting points on the curve corresponding to the end points of the slope threshold range of the curve to obtain the reference line for each opening displacement, includes: and connecting the point with the slope of 0 with the point with the slope of 0.95 on the curve to obtain a reference straight line of each opening displacement.
Specifically, during the loading process of the test-grade rock sample, the opening displacement measured by the virtual displacement meter will change with the increase of the loading time. At the early stage of loading, the internal damage at the tip of the crack (I-type in another embodiment) is small, and the deformation is mainly in an elastic deformation stage, so that a fracture process area is not formed at this time and the change of the opening displacement is not obvious. When the loading is increased to a certain extent, the opening displacement measured by the virtual displacement meter at the crack tip will have a rapidly increasing trend of change. The test process is recorded by the ultra-high-speed camera, and the change process of rapid increase of the opening displacement can be well captured and calculated. FIG. 5 is a 1 st virtual displacement meter L at the tip of a type I crack1The change rule of the opening displacement along with the loading time, which is calculated by a digital image correlation method, is the opening displacement u1A rapidly increasing trend of change is exhibited in the region a. With the region A as the object of study, the opening displacement u in the range can be obtained1The trend with the duration of loading is shown in fig. 6. Two points on the curve with a slope close to 0 and a slope close to 1 are connected (it should be noted that, within the range of the slope threshold 0 to 1, two points close to the slopes 0 and 1 may be selected, and the maximum value of the difference may be included), so as to form the reference line 602. In the vertical directionThe opening displacement of each point on the curve is subtracted from the opening displacement on the reference line, so that an opening displacement difference 601 (which can be recorded as Δ u) can be obtained.
Based on the content of the foregoing method embodiment, as an optional embodiment, the method for determining a propagation velocity of a fracture process zone of a crack tip of a rock material provided in the embodiment of the present invention, where the obtaining the propagation velocity of the fracture process zone of the crack tip corresponding to each opening displacement according to the distance and the corresponding time duration includes:
wherein v isi+1The propagation speed of a crack tip fracture process area between the ith virtual displacement meter and the (i + 1) th virtual displacement meter is measured; u is the distance; t is ti+1And tiThe time length for the fracture process zone to reach the (i + 1) th and (i) th virtual displacement meters (i.e., the corresponding time length).
Specifically, the obtained opening displacement difference value and the loading time period are plotted as a curve, as shown in fig. 7. The opening displacement difference value delta u has a maximum value in the loading time period, so the time period corresponding to the maximum value is the time period from the fracture process area to the 1 st virtual displacement meter L1Time duration t1. Repeatedly obtaining t1Can calculate and solve the problem that the fracture process zone reaches other virtual displacement meters L2To LnTime duration t2To tn. Based on the calculated time for the fracture process zone to reach the virtual displacement meter and the distance (i.e. u, the distance) between the virtual displacement meters, ratio processing is performed to obtain the propagation velocity of the fracture process zone in different interval ranges, as shown in formula (3).
Based on the content of the foregoing method embodiment, as an optional embodiment, the method for determining a propagation velocity of a fracture process zone at a crack tip of a rock material provided in the embodiment of the present invention further includes, before the loading the test-grade rock sample: drilling and cutting a rock material to prepare a Brazilian disc-shaped rock sample, and blackening and whitening the Brazilian disc-shaped rock sample to obtain the test-grade rock sample.
Specifically, the rock material to be investigated is made into a specimen in the shape of a pucks by drilling and cutting, the specimen size being 50mm diameter by 25mm thickness. To prepare cracks in the material (in another embodiment, type I cracks can be obtained), a crack with a length of 10mm and a width of 1mm can be cut in the center of the sample by means of water jet cutting and wire cutting, and a brazilian disc-shaped rock sample is obtained, as shown in fig. 8.
Based on the content of the above method embodiment, as an alternative embodiment, the method for determining the propagation velocity of the fracture process zone at the crack tip of the rock material provided in the embodiment of the present invention further performs black whitening on the brazilian disc rock sample, including: and uniformly spraying white matte paint on the surface of the Brazilian disc-shaped rock sample, and after the white matte paint is solidified, randomly spraying black matte paint on the upper part of the white matte paint to form black and white speckles.
Specifically, before the test is started, the surface of the Brazilian disc-shaped rock sample is uniformly sprayed to be white by adopting white matte paint, and the sample is kept stand for dozens of minutes to wait for the solidification of the white matte paint. And then, randomly spraying black matte paint on the upper part of the white matte paint, so that a black and white speckle pattern can be formed on the surface of the Brazilian disc-shaped rock sample, and finally obtaining the test-grade rock sample, as shown in fig. 9. The test-grade rock sample is placed on loading equipment for developing the Brazilian disc splitting test, and the direction of the prefabricated crack and the loading direction are ensured to be on the same axis. With this arrangement, the crack produced by the pre-crack tip will be an I-type crack and the displacements on both sides thereof will be mainly opening displacements. In addition, an ultra-high speed camera is required to be placed right in front of the test-grade rock sample in the test process to record the damage process, the axial direction of the camera is required to be as vertical as possible to the surface of the test-grade rock sample, and then the test is carried out.
The method for determining the propagation speed of the fracture process area of the crack tip of the rock material provided by the embodiment of the invention can finally obtain the propagation speed of the fracture process area of the crack tip by obtaining the full-field displacement distribution of the surface of a test-grade rock sample, arranging a plurality of virtual displacement meters on a discontinuous line of the crack tip to obtain opening displacement sets at different loading moments and corresponding duration of a reference straight line of each opening displacement and a maximum value of a curve difference value, and realizes the quantitative analysis of the evolution and propagation of the fracture process area of the crack tip.
The implementation basis of the various embodiments of the present invention is realized by programmed processing performed by a device having a processor function. Therefore, in engineering practice, the technical solutions and functions thereof of the embodiments of the present invention can be packaged into various modules. Based on this real situation, on the basis of the embodiments described above, embodiments of the present invention provide an apparatus for determining a propagation velocity of a fracture process zone of a crack tip of a rock material, the apparatus being configured to perform the method for determining a propagation velocity of a fracture process zone of a crack tip of a rock material according to the above-described method embodiments. Referring to fig. 2, the apparatus includes:
the full-field displacement distribution module is used for loading the test-grade rock sample, acquiring a plurality of pictures according to the time interval, and acquiring the full-field displacement distribution of the surface of the test-grade rock sample according to the pictures; the virtual displacement meter module is used for distributing a plurality of virtual displacement meters at a distance on a discontinuous line of the crack tip and obtaining an opening displacement set of the crack tip at different loading moments according to the time intervals; a difference module, configured to connect, in a curve inflection point region of each opening displacement in the opening displacement set, points on the curve corresponding to an end point of a curve slope threshold range to obtain a reference line of each opening displacement, and obtain a corresponding duration of a maximum value of a difference between the curve and the reference line in a vertical direction; and the propagation speed module is used for obtaining the propagation speed of the crack tip fracture process area corresponding to each opening displacement according to the distance and the corresponding duration.
The device for determining the propagation speed of the fracture process area of the crack tip of the rock material provided by the embodiment of the invention adopts various modules in the figure 2, obtains the opening displacement sets at different loading moments by obtaining the full-field displacement distribution of the surface of a test-grade rock sample and distributing a plurality of virtual displacement meters on a discontinuous line of the crack tip, and finally obtains the propagation speed of the fracture process area of the crack tip and realizes the quantitative analysis of the evolution and propagation of the fracture process area of the crack tip.
It should be noted that, the apparatus in the apparatus embodiment provided by the present invention may be used for implementing methods in other method embodiments provided by the present invention, except that corresponding function modules are provided, and the principle of the apparatus embodiment provided by the present invention is basically the same as that of the apparatus embodiment provided by the present invention, so long as a person skilled in the art obtains corresponding technical means by combining technical features on the basis of the apparatus embodiment described above, and obtains a technical solution formed by these technical means, on the premise of ensuring that the technical solution has practicability, the apparatus in the apparatus embodiment described above may be modified, so as to obtain a corresponding apparatus class embodiment, which is used for implementing methods in other method class embodiments. For example:
based on the content of the above embodiment of the apparatus, as an optional embodiment, the apparatus for determining a propagation velocity of a fracture process zone at a crack tip of a rock material provided in an embodiment of the present invention further includes: a second module for achieving full field displacement distribution of the test grade rock sample surface, comprising:
wherein u isi,xAnd ui,yRespectively displacement of the ith point in the picture along the x direction and the y direction; u. of0And v0Displacement along the x direction and the y direction at the central point respectively; (x)0,y0) And (x)i,yi) Respectively as coordinates of the center pointAnd coordinates at the ith point; the partial derivative of u or v with respect to the coordinate x or y is the gradient of the displacement along the x-axis or y-axis.
Based on the content of the above embodiment of the apparatus, as an optional embodiment, the apparatus for determining a propagation velocity of a fracture process zone at a crack tip of a rock material provided in an embodiment of the present invention further includes: a third module, configured to implement the different loading moments, including:
t＝n×Δt
wherein t is the loading time; n is the number of the plurality of virtual displacement meters; Δ t is the duration interval.
Based on the content of the above embodiment of the apparatus, as an optional embodiment, the apparatus for determining a propagation velocity of a fracture process zone at a crack tip of a rock material provided in an embodiment of the present invention further includes: a fourth module, configured to implement the slope threshold range from 0 to 0.95, and correspondingly, connect points on the curve corresponding to endpoints of the slope threshold range of the curve to obtain a reference line for each opening displacement, where the fourth module includes: and connecting the point with the slope of 0 with the point with the slope of 0.95 on the curve to obtain a reference straight line of each opening displacement.
Based on the content of the above embodiment of the apparatus, as an optional embodiment, the apparatus for determining a propagation velocity of a fracture process zone at a crack tip of a rock material provided in an embodiment of the present invention further includes: a fifth module, configured to obtain, according to the distance and the corresponding duration, a propagation speed of the crack tip fracture process area corresponding to each opening displacement, where the fifth module includes:
wherein v isi+1The propagation speed of a crack tip fracture process area between the ith virtual displacement meter and the (i + 1) th virtual displacement meter is measured; u is the distance; t is ti+1And tiThe time length of the fracture process zone reaching the (i + 1) th and the (i) th virtual displacement meters is shown.
Based on the content of the above embodiment of the apparatus, as an optional embodiment, the apparatus for determining a propagation velocity of a fracture process zone at a crack tip of a rock material provided in an embodiment of the present invention further includes: a sixth module, configured to implement before the loading of the test-grade rock sample, further including: drilling and cutting a rock material to prepare a Brazilian disc-shaped rock sample, and blackening and whitening the Brazilian disc-shaped rock sample to obtain the test-grade rock sample.
Based on the content of the above embodiment of the apparatus, as an optional embodiment, the apparatus for determining a propagation velocity of a fracture process zone at a crack tip of a rock material provided in an embodiment of the present invention further includes: a seventh module for performing the blackening and whitening of the brazilian disc rock sample, comprising: and uniformly spraying white matte paint on the surface of the Brazilian disc-shaped rock sample, and after the white matte paint is solidified, randomly spraying black matte paint on the upper part of the white matte paint to form black and white speckles.
The method of the embodiment of the invention is realized by depending on the electronic equipment, so that the related electronic equipment is necessarily introduced. To this end, an embodiment of the present invention provides an electronic apparatus, as shown in fig. 3, including: at least one processor (processor)301, a communication Interface (Communications Interface)304, at least one memory (memory)302 and a communication bus 303, wherein the at least one processor 301, the communication Interface 304 and the at least one memory 302 are configured to communicate with each other via the communication bus 303. The at least one processor 301 may invoke logic instructions in the at least one memory 302 to perform all or a portion of the steps of the methods provided by the various method embodiments described above.
Furthermore, the logic instructions in the at least one memory 302 may be implemented in software functional units and stored in a computer readable storage medium when sold or used as a stand-alone product. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the method embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.
The above-described embodiments of the apparatus are merely illustrative, and the units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.
Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware. With this understanding in mind, the above-described technical solutions may be embodied in the form of a software product, which can be stored in a computer-readable storage medium such as ROM/RAM, magnetic disk, optical disk, etc., and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the methods described in the embodiments or some parts of the embodiments.
The flowchart and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to various embodiments of the present invention. Based on this recognition, each block in the flowchart or block diagrams may represent a module, a program segment, or a portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems which perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.
In this patent, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (10)
1. A method of determining the propagation velocity in a fracture process zone at a crack tip of a rock material, comprising: loading a test-grade rock sample, acquiring a plurality of pictures according to time intervals, and obtaining full-field displacement distribution of the surface of the test-grade rock sample according to the pictures; arranging a plurality of virtual displacement meters on a discontinuous line of the crack tip at a distance, and obtaining an opening displacement set of the crack tip at different loading moments according to the time intervals; in the curve inflection point region of each expansion displacement in the expansion displacement set, connecting points on the curve corresponding to the end points of the curve slope threshold range to obtain a reference straight line of each expansion displacement, and acquiring the corresponding duration of the maximum value of the difference value between the curve and the reference straight line in the vertical direction; and obtaining the propagation speed of the crack tip fracture process area corresponding to each opening displacement according to the distance and the corresponding duration.
2. The method of determining propagation velocity in a region of a fracture process at a crack tip of a rock material according to claim 1, wherein the full field displacement profile of the surface of the test grade rock sample comprises:
wherein u isi,xAnd ui,yRespectively displacement of the ith point in the picture along the x direction and the y direction; u. of0And v0Displacement along the x direction and the y direction at the central point respectively; (x)0,y0) And (x)i,yi) Respectively a coordinate at the central point and a coordinate at the ith point; the partial derivative of u or v with respect to the coordinate x or y is the gradient of the displacement along the x-axis or y-axis.
3. The method of determining propagation velocity in a fracture process zone of a crack tip of a rock material as claimed in claim 1, wherein said different loading moments comprise:
t＝n×Δt
wherein t is the loading time; n is the number of the plurality of virtual displacement meters; Δ t is the duration interval.
4. A method for determining propagation velocity in a fracture process zone of a crack tip of a rock material according to claim 1, wherein the slope threshold range is 0 to 0.95, and correspondingly, the connecting points on the curve corresponding to the end points of the slope threshold range of the curve to obtain the reference line for each opening displacement comprises: and connecting the point with the slope of 0 with the point with the slope of 0.95 on the curve to obtain a reference straight line of each opening displacement.
5. The method for determining propagation velocity of a fracture process zone of a crack tip of a rock material according to claim 1, wherein the obtaining the propagation velocity of the fracture process zone of the crack tip for each opening displacement according to the distance and the corresponding time duration comprises:
wherein v isi+1The propagation speed of a crack tip fracture process area between the ith virtual displacement meter and the (i + 1) th virtual displacement meter is measured; u is the distance; t is ti+1And tiThe time length of the fracture process zone reaching the (i + 1) th and the (i) th virtual displacement meters is shown.
6. The method of determining propagation velocity in a region of a rock material crack tip fracture process as claimed in claim 1, further comprising, prior to said loading the test grade rock sample: drilling and cutting a rock material to prepare a Brazilian disc-shaped rock sample, and blackening and whitening the Brazilian disc-shaped rock sample to obtain the test-grade rock sample.
7. The method for determining the propagation velocity of a crack tip fracture process zone of a rocky material according to claim 6, wherein the blackening and whitening of the Brazilian disc rock sample comprises: and uniformly spraying white matte paint on the surface of the Brazilian disc-shaped rock sample, and after the white matte paint is solidified, randomly spraying black matte paint on the upper part of the white matte paint to form black and white speckles.
8. An apparatus for determining the propagation velocity in a fracture process zone at the tip of a crack in rock material, comprising:
the full-field displacement distribution module is used for loading the test-grade rock sample, acquiring a plurality of pictures according to the time interval, and acquiring the full-field displacement distribution of the surface of the test-grade rock sample according to the pictures; the virtual displacement meter module is used for distributing a plurality of virtual displacement meters at a distance on a discontinuous line of the crack tip and obtaining an opening displacement set of the crack tip at different loading moments according to the time intervals; a difference module, configured to connect, in a curve inflection point region of each opening displacement in the opening displacement set, points on the curve corresponding to an end point of a curve slope threshold range to obtain a reference line of each opening displacement, and obtain a corresponding duration of a maximum value of a difference between the curve and the reference line in a vertical direction; and the propagation speed module is used for obtaining the propagation speed of the crack tip fracture process area corresponding to each opening displacement according to the distance and the corresponding duration.
9. An electronic device, comprising:
at least one processor, at least one memory, and a communication interface; wherein the content of the first and second substances,
the processor, the memory and the communication interface are communicated with each other;
the memory stores program instructions executable by the processor, the processor invoking the program instructions to perform the method of any of claims 1 to 7.
10. A non-transitory computer-readable storage medium storing computer instructions for causing a computer to perform the method of any one of claims 1 to 7.
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| CN115791460A (en) * | 2022-11-18 | 2023-03-14 | 中国矿业大学 | Sensor for propagation speed of blasting crack in rock material and testing method thereof |
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