A three-dimensional monomer rough crack modeling method, system, equipment and medium

Abstract

The present invention relates to a three-dimensional monomer rough crack modeling method, system, equipment and medium, and the method includes: performing contour processing through a one-dimensional random rough surface generating function to obtain a crack model with an irregular contour; performing surface processing through a two-dimensional random rough surface generating function to obtain a crack model with a rough and uneven surface; obtaining a crack model with a spatial morphology through spatial transformation; and performing numerical simulation of crack detection based on the crack model with a spatial morphology. The present invention uses an ellipsoid to set parameters for simulating crack thickness, and constructs the basic shape of the crack in accordance with the characteristics of edge pinch-out; uses one-dimensional and two-dimensional random rough surfaces in turn to depict the irregular contour of the crack and the rough and undulating surface of the crack, and forms a crack with a spatial distribution through spatial transformations such as translation changes and rotation transformations. The crack model with a spatial morphology finally generated by the present invention has the characteristics of irregularity, pinch-out, roughness, etc., and is closer to the actual crack.

Description

Technical Field

[0001] The present invention relates to the technical field of crack modeling, and in particular to a three-dimensional monomer rough crack modeling method, system, equipment and medium. Background Art

[0002] Fractures refer to surface discontinuities without obvious displacement formed by the fracture of rocks due to structural deformation or physical diagenesis. Fractures play an important role in many engineering fields. For example, in petroleum engineering, fractures mainly play a role in storage and seepage; in hydrogeology, fractures are the main seepage channels and play a leading role in the process of water pollution; in nuclear engineering, the location and migration capacity of fracture zones are important evaluation criteria for the selection of nuclear waste storage sites; in addition, the study of the spatial distribution of fractures is of great significance to geothermal development, mining, geotechnical engineering, engineering exploration and other fields.

[0003] Since in most practical cases, cracks cannot be observed directly and can only be observed and studied at their intersections with boreholes, outcrops or offsets, numerical simulation can avoid this limitation and thus become an effective means of studying cracks. Crack modeling is a key step in numerical simulation of cracks, and researchers have proposed some crack modeling methods. The flat plate model is a commonly used crack model. Because it is simple and easy to implement, many scholars use this model to carry out research. However, the flat plate model is only a simple approximation of the crack. The cracks in reality are not smooth planes, but rough and irregular. Therefore, the simulation results using the flat plate model are significantly different from the actual crack response. The Baecher disk model is a discrete crack grid model constructed based on the fact that the possible shape of a real crack is a rough circle or ellipse. Subsequently, some improved models have emerged, such as the enhanced Baecher model, the BART model, the random polygon model, etc. These crack models take into account the shape characteristics of the cracks well, but cannot set parameters such as the thickness and roughness of the cracks. For the simulation study of single cracks, these discrete crack grid modeling methods lack accurate characterization of the cracks. The Brown crack model consists of two random rough surfaces, and the roughness of the crack can be described by fractal dimension, root mean square height, and correlation length. The Brown crack model takes into account the characteristics of the rough surface of the crack, but it is an unbounded model that does not involve the construction of the crack contour and ignores the characteristics of the crack edge pinching out and irregular shape.

[0004] Therefore, the existing crack simulation does not have a crack model that can simultaneously reflect the characteristics of roughness, pinch-out, irregularity, etc. The crack model obtained by using an unreasonable crack modeling method is quite different from the actual crack, and the results obtained after simulation with such a crack model are also unreliable. Summary of the invention

[0005] 1. Technical issues to be resolved

[0006] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a three-dimensional monomer rough crack modeling method, which solves the technical problem that the existing crack simulation has not yet had a crack model that can simultaneously reflect the characteristics of roughness, pinch-out, irregularity, etc.

[0007] (II) Technical solution

[0008] In order to achieve the above object, the main technical solutions adopted by the present invention include:

[0009] In a first aspect, an embodiment of the present invention provides a three-dimensional monomer rough crack modeling method, the method comprising:

[0010] The preset three-dimensional crack basic shape is processed by a one-dimensional random rough surface generation function to obtain a crack model with irregular contour;

[0011] Performing surface processing on the irregular-contour crack model by using a two-dimensional random rough surface generation function to obtain a crack model with a rough surface;

[0012] Performing spatial transformation on the crack model with a rough surface to obtain a crack model with a spatial form;

[0013] A numerical simulation of crack detection is performed based on the crack model with spatial morphology.

[0014] Optionally, the basic shape of the crack includes an ellipsoid, and the ellipsoid satisfies:

[0015]

[0016] Among them, a>b>c, a is the length of the major semiaxis, b is the length of the middle semiaxis, and c is the length of the minor semiaxis; a and b affect the contour of the xoy surface of the ellipsoid, and c is in the z direction of the ellipsoid; twice the minor semiaxis c is the crack thickness.

[0017] Optionally, contour processing is performed on a preset three-dimensional crack basic shape by a one-dimensional random rough surface generating function to obtain a crack model with an irregular contour, including:

[0018] Based on a one-dimensional random rough surface generating function of a Gaussian spectrum, two one-dimensional random rough surfaces are obtained, which are used to respectively describe the upper and lower contours of the xoy surface of the basic shape of the crack;

[0019] Superimposing two one-dimensional random rough surfaces on the upper and lower contours of the crack according to a first ratio, respectively, to obtain a new crack contour;

[0020] Making a determination based on the new crack profile and the basic shape of the crack;

[0021] If the new crack contour is included in the basic shape of the crack, the new crack contour is retained to obtain a crack model with an irregular contour;

[0022] If the new crack contour is not included in the basic crack shape, the contour of the basic crack shape is retained to obtain a crack model with an irregular contour;

[0023] The one-dimensional random rough surface used to describe the upper contour of the xoy surface of the basic shape of the crack has a different value from the one-dimensional random rough surface used to describe the lower contour of the xoy surface of the basic shape of the crack.

[0024] Optionally,

[0025] The one-dimensional random rough surface generation function based on Gaussian spectrum is:

[0026]

[0027] Among them, x n =nΔx (n = -N / 2+1, ..., N / 2) represents the nth sampling point on a one-dimensional random rough surface, L is the generation length, N is the number of equally spaced discrete points, Δx is the distance between two adjacent points, F(k j ) and f(x n ) is called the Fourier transform pair and is defined as:

[0028]

[0029] In which, the discrete wave number k is defined j The expression for k j =2πj / L, S(k j ) is the power spectral density of a one-dimensional random rough surface, N(0,1) represents a normally distributed random number with a mean of 0 and a variance of 1;

[0030] The power spectral density of the one-dimensional random rough surface is:

[0031]

[0032] Where δ1 is the average root height of the one-dimensional rough surface; l is the correlation length;

[0033] The first ratio is:

[0034] y c =y b +y b ·y a / n

[0035] Among them, y c is the upper contour of the crack after superposition, y b is the upper contour of the crack before superposition, ya is a one-dimensional random rough surface used to describe the upper contour of the xoy surface of the basic shape of the crack, n is a scale factor, and the scale factor n can be taken to y b The maximum value of .

[0036] Optionally, performing surface processing on the irregular-profile crack model by using a two-dimensional random rough surface generating function to obtain a crack model with a rough surface includes:

[0037] Based on a two-dimensional random rough surface generating function of a Gaussian spectrum, two two-dimensional random rough surfaces are obtained, which are used to respectively describe the upper and lower surfaces of the crack model with irregular contours;

[0038] Superimposing two two-dimensional random rough surfaces on the upper and lower surfaces of the irregularly contoured crack model according to a second ratio, respectively, to obtain a new crack surface;

[0039] The two-dimensional random rough surface used to depict the upper surface of the crack model with irregular contour has a different value from the two-dimensional random rough surface used to depict the lower surface of the crack model with irregular contour.

[0040] Optionally,

[0041] The two-dimensional random rough surface generation function based on Gaussian spectrum is:

[0042]

[0043] where x m =mΔx(m=-M / 2+1,…,M / 2), y n =nΔy (n = -N / 2+1, ..., N / 2) represent the mth sampling point in the x direction and the nth sampling point in the y direction on the two-dimensional random rough surface, respectively. x and L y are the generated lengths in the x and y directions, M and N are the number of equally spaced discrete points in the x and y directions, Δx and Δy are the distances between two adjacent points in the x and y directions, With f(x m ,y n ) is called the Fourier transform pair and is defined as:

[0044]

[0045] The discrete wave number is defined as and The expressions are is the power spectral density of the two-dimensional random rough surface;

[0046] The power spectral density of the two-dimensional random rough surface is:

[0047]

[0048] Where δ2 is the root mean square height of the two-dimensional rough surface; l x and l y are the correlation lengths along the x and y directions, respectively;

[0049] The second ratio is:

[0050] z c =z b +z b ·z a / m

[0051] Among them, z c is the upper surface of the crack after superposition, z b is the upper surface of the crack before superposition, z a is a two-dimensional random rough surface used to characterize the upper surface of the crack, m is a scale factor, and the scale factor m can be taken to z b The maximum value of .

[0052] Optionally, performing spatial transformation on the crack model with a rough surface to obtain a crack model with a spatial form includes:

[0053] Add corresponding translation parameters in the XYZ directions of the crack model with a rough surface;

[0054] Translating the crack center of the crack model with a rough surface from the starting point to the origin;

[0055] The crack model with a rough surface is rotated around the x-axis, the y-axis and the z-axis respectively;

[0056] The crack center of the rotated crack model with rough surface is translated back from the origin to the starting point;

[0057] The translation parameters include an x ​​translation amount, a y translation amount, and a z translation amount.

[0058] In a second aspect, an embodiment of the present invention provides a three-dimensional monomer rough crack modeling system, comprising:

[0059] A contour processing module is used to perform contour processing on a preset three-dimensional crack basic shape through a one-dimensional random rough surface generation function to obtain a crack model with an irregular contour;

[0060] A surface processing module, used for performing surface processing on the irregular-contour crack model by using a two-dimensional random rough surface generation function to obtain a crack model with a rough surface;

[0061] A spatial transformation module, used for performing spatial transformation on the crack model with a rough surface to obtain a crack model with a spatial form;

[0062] The numerical simulation module is used to perform numerical simulation of crack detection based on the crack model with spatial morphology.

[0063] In the third aspect, an embodiment of the present invention provides a three-dimensional monomer rough crack modeling device, comprising: at least one database; and a memory communicatively connected to the at least one database; wherein the memory stores instructions executable by the at least one database, and the instructions are executed by the at least one database so that the at least one database can execute a three-dimensional monomer rough crack modeling method as described above.

[0064] In a fourth aspect, an embodiment of the present invention provides a computer-readable medium having computer executable instructions stored thereon, and when the executable instructions are executed by a processor, the three-dimensional monomer rough crack modeling method as described above is implemented.

[0065] (III) Beneficial effects

[0066] The beneficial effects of the present invention are as follows: the present invention can set the parameters of the simulated crack thickness by using an ellipsoid, and construct the basic shape of the crack in accordance with the characteristics of edge pinching out; based on the basic shape of the crack, the irregular outline of the crack and the rough and undulating surface of the crack are depicted by using one-dimensional and two-dimensional random rough surfaces in turn, and the degree of roughness can be quantitatively adjusted by using the correlation length and the average root height; the crack is subjected to spatial transformations such as translational change and rotational transformation to form a crack with spatial distribution. The crack model with spatial morphology finally generated by the present invention has the characteristics of irregularity, pinching out, roughness, etc., and is closer to the actual crack. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Figure 1 A schematic flow chart of a three-dimensional monomer rough crack modeling method provided by an embodiment of the present invention;

[0068] Figure 2 A specific flow chart of step S1 of a three-dimensional monomer rough crack modeling method provided by an embodiment of the present invention;

[0069] Figure 3 A specific flow chart of step S2 of a three-dimensional monomer rough crack modeling method provided by an embodiment of the present invention;

[0070] Figure 4 A modeling process evolution diagram of a three-dimensional monomer rough crack modeling method provided by an embodiment of the present invention;

[0071] Figure 5A schematic diagram of a specific flow chart of step S3 of a three-dimensional monomer rough crack modeling method provided by an embodiment of the present invention;

[0072] Figure 6 A crack contour characterization process evolution diagram of a three-dimensional monomer rough crack modeling method provided by an embodiment of the present invention;

[0073] Figure 7 A crack variation diagram at different roughness levels of a three-dimensional monomer rough crack modeling method provided by an embodiment of the present invention;

[0074] Figure 8 A crack discretization process of a three-dimensional monomer rough crack modeling method provided by an embodiment of the present invention;

[0075] Fig. 9 A model slice diagram of a three-dimensional monomer rough crack modeling method provided by an embodiment of the present invention;

[0076] Fig.10 A schematic diagram of crack simulation results of a three-dimensional monomer rough crack modeling method provided by an embodiment of the present invention;

[0077] Fig.11 A schematic diagram of the composition of a three-dimensional monomer rough crack modeling system provided in an embodiment of the present invention.

[0078] [Description of Reference Numerals]

[0079] 100: Three-dimensional monomer rough crack modeling system;

[0080] 110: contour processing module;

[0081] 120: surface treatment module;

[0082] 130: spatial transformation module;

[0083] 140: Numerical simulation module. DETAILED DESCRIPTION

[0084] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below through specific implementation modes in conjunction with the accompanying drawings.

[0085] like Figure 1As shown, a three-dimensional monomer rough crack modeling method proposed in an embodiment of the present invention is implemented based on a spatial rectangular coordinate system, and the method includes: first, contour processing is performed on the basic shape of the three-dimensional crack through a one-dimensional random rough surface generating function to obtain a crack model with an irregular contour; secondly, surface processing is performed on the crack model with an irregular contour through a two-dimensional random rough surface generating function to obtain a crack model with a rough surface; then, spatial transformation is performed on the crack model with a rough surface to obtain a crack model with a spatial morphology; finally, numerical simulation of crack detection is performed based on the crack model with a spatial morphology.

[0086] The present invention uses an ellipsoid to set parameters for simulating crack thickness, and constructs the basic shape of the crack in accordance with the characteristics of edge pinching out; based on the basic shape of the crack, one-dimensional and two-dimensional random rough surfaces are used in turn to depict the irregular outline of the crack and the rough and undulating surface of the crack, and the correlation length and average root height can be used to quantitatively adjust the roughness; the crack is subjected to spatial transformations such as translation and rotation transformation to form a crack with spatial distribution. The crack model with spatial morphology finally generated by the present invention has the characteristics of irregularity, pinching out, roughness, etc., and is closer to the actual crack.

[0087] In order to better understand the above technical solution, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a clearer and more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0088] Specifically, the present invention provides a three-dimensional monomer rough crack modeling method, comprising:

[0089] S1. Use a one-dimensional random rough plane to perform contour processing on the basic shape of the three-dimensional crack to obtain a crack model with an irregular contour.

[0090] A simple three-dimensional shape can be selected as the basic shape for the crack model. The actual crack is a rough circular or elliptical thin disk, such as Figure 4 As shown in (a), the present invention adopts an ellipsoid as the basic form of the crack. The reason why an ellipsoid is chosen instead of a thin disk is that the thickness information can be set for the ellipsoid. When the thickness (length in the direction of the short semi-axis) decreases to 0, it degenerates into a thin disk. The thin disk is a special case of the ellipsoid. Although the thickness of the actual crack is very small, the thickness will still affect the response of the crack, and the thickness information needs to be considered. Another feature of the crack is the edge pinching out, that is, the edge gradually approaches zero, and the ellipsoid can reflect this. After comprehensive consideration, it is more common and reasonable to use the ellipsoid as the basic form of the crack.

[0091] The contour of an actual crack is unlikely to be a complete circle or ellipse (ellipsoid contour). Taking this into consideration, a one-dimensional random rough surface is added to the ellipsoid contour to make the crack contour irregular.

[0092] The basic shape of the crack includes an ellipsoid, and the ellipsoid satisfies:

[0093]

[0094] Among them, a>b>c, a is the length of the major semiaxis, b is the length of the middle semiaxis, and c is the length of the minor semiaxis; a and b mainly affect the contour of the xoy surface of the ellipsoid, and c is in the z direction of the ellipsoid; twice the minor semiaxis c is the crack thickness.

[0095] like Figure 2 As shown, step S1 includes:

[0096] S11. Based on the one-dimensional random rough surface generation function of the Gaussian spectrum, two one-dimensional random rough surfaces are obtained, which are used to describe the upper and lower contours of the xoy surface of the basic shape of the crack. Figure 6 As shown in (b), Upper refers to the upper contour and Lower refers to the lower contour. In other words, the xoy surface (ellipse) is divided into two parts, the upper part is the upper contour (y is greater than 0), and the lower part is the lower contour (y is less than 0). The upper contour and the lower contour are separated by the straight line where y=0. y>0 is the upper contour and y<0 is the lower contour.

[0097] S12, superimposing two one-dimensional random rough surfaces on the upper and lower contours of the crack according to a first ratio, to obtain a new crack contour.

[0098] S13. Make a determination based on the new crack outline and the basic shape of the crack.

[0099] S14a. If the new crack contour is included in the basic shape of the crack, the new crack contour is retained to obtain a crack model with an irregular contour.

[0100] S14b, if the new crack contour is not included in the basic crack shape, retain the contour of the basic crack shape, and obtain the following Figure 4 (b) The crack model with irregular contour is shown.

[0101] The one-dimensional random rough surface used to describe the upper contour of the xoy surface of the basic shape of the crack has a different value from the one-dimensional random rough surface used to describe the lower contour of the xoy surface of the basic shape of the crack. The value here can refer to the y coordinate value. That is, Figure 6 The value of y in (a).

[0102] Further,

[0103] The one-dimensional random rough surface generation function based on Gaussian spectrum is:

[0104]

[0105] Among them, x n =nΔx (n = -N / 2+1, ..., N / 2) represents the nth sampling point on a one-dimensional random rough surface, L is the generation length, N is the number of equally spaced discrete points, Δx is the distance between two adjacent points, F(k j ) and f(x n ) is called the Fourier transform pair and is defined as:

[0106]

[0107] In which, the discrete wave number k is defined j The expression for k j =2πj / L, S(k j ) is the power spectral density of a one-dimensional random rough surface, N(0,1) represents a normally distributed random number with a mean of 0 and a variance of 1;

[0108] The power spectral density of the one-dimensional random rough surface is:

[0109]

[0110] Among them, δ1 is the mean root height of the one-dimensional rough surface, which determines the scale of the rough surface in the y direction (vertical direction); l is the correlation length, which is related to the scale of the rough surface in the x direction (horizontal direction); k is the wave number;

[0111] The first ratio is:

[0112] y c =y b +y b ·y a / n

[0113] Among them, y c is the crack contour after superposition, y b is the upper contour of the crack before superposition, y a is a one-dimensional random rough surface used to describe the upper contour of the xoy surface of the basic shape of the crack, n is the scale factor, and the scale factor n can be taken to y b The maximum value of .

[0114] S2. Use a two-dimensional random rough surface to depict the surface of the crack model with irregular contours to obtain a crack model with a rough and uneven surface.

[0115] like Figure 3 As shown, step S2 includes:

[0116] S21. Based on the two-dimensional random rough surface generation function of the Gaussian spectrum, two two-dimensional random rough surfaces are obtained, which are used to describe the upper and lower surfaces of the crack model with irregular contours. Figure 4 As shown in (b), the xoy plane where z=0 is the boundary, the upper half is the upper surface (z is greater than 0), and the lower half is the lower surface (z is less than 0). The upper and lower surfaces are divided according to the z coordinate, z>0 is the upper surface, and z<0 is the lower surface.

[0117] S22, superimposing two two-dimensional random rough surfaces on the upper and lower surfaces of the irregularly contoured crack model according to the second ratio, to obtain a new crack surface, and then obtain the following: Figure 4 (b) Crack model with rough surface shown.

[0118] The values ​​of the two-dimensional random rough surface on the upper surface of the crack model with irregular contour and the two-dimensional random rough surface on the lower surface of the crack model with irregular contour are different. The values ​​here may refer to the z coordinate value. That is, Figure 4 The value of z in (b).

[0119] Further,

[0120] The two-dimensional random rough surface generation function based on Gaussian spectrum is:

[0121]

[0122] where x m =mΔx(m=-M / 2+1,…,M / 2), y n =nΔy (n = -N / 2+1, ..., N / 2) represent the mth sampling point in the x direction and the nth sampling point in the y direction on the two-dimensional random rough surface, respectively. x and L y are the generated lengths in the x and y directions, M and N are the number of equally spaced discrete points in the x and y directions, Δx and Δy are the distances between two adjacent points in the x and y directions, With f(x m ,y n ) is called the Fourier transform pair and is defined as:

[0123]

[0124] The discrete wave number is defined as and The expressions are is the power spectral density of the two-dimensional random rough surface;

[0125] The power spectral density of the two-dimensional random rough surface is:

[0126]

[0127] Among them, δ2 is the root mean square height of the two-dimensional rough surface, which determines the scale of the rough surface in the z direction (vertical direction); l x and l y are the correlation lengths along the x and y directions, respectively, which are related to the scale of the rough surface in the x and y directions (horizontal direction); k x and k y are the wave numbers of the rough surface in the x and y directions, respectively;

[0128] The second ratio is:

[0129] z c =z b +z b ·z a / m

[0130] Among them, z c is the upper surface of the crack after superposition, z b is the upper surface of the crack before superposition, z a is a two-dimensional random rough surface used to characterize the upper surface of the crack, m is a scale factor, and the scale factor m can be taken to z b The maximum value of .

[0131] In the above method, roughness is also an important feature of cracks. For this purpose, a two-dimensional random rough surface is added to the surface of the ellipsoid. Whether it is a one-dimensional random rough surface or a two-dimensional random rough surface, the degree of roughness can be quantitatively adjusted by using the correlation length and the mean square root height. Therefore, it is possible to quantitatively describe the roughness characteristics of cracks. The simple rule of rough cracks is: the smaller the correlation length, the rougher the crack; the larger the root mean square height, the rougher the crack. The cracks obtained through the above steps already have characteristics such as roughness, pinching out, and irregularity, which are more consistent with actual cracks. In addition, various forms of cracks can be changed by adjusting parameters. After setting the parameters, the crack model is automatically generated, which is far better than artificial characterization of cracks.

[0132] S3. Perform spatial transformation on the crack model with a rough surface to obtain a crack model with a spatial shape. Figure 4 (d) shows the crack after spatial transformation.

[0133] like Figure 5 As shown, step S3 includes:

[0134] S31. Perform the following translation transformation on the crack model with a rough surface.

[0135] S32. Add corresponding translation parameters in the XYZ directions of the crack model with a rough surface.

[0136] S33, translating the crack center of the crack model with a rough surface from the starting point to the origin.

[0137] S34, respectively rotating the crack model with a rough surface around the x-axis, around the y-axis, and around the z-axis, wherein the angles around the x-axis, around the y-axis, and around the z-axis are artificially selected. Figure 4 (c) to Figure 4 (d) A 30 degree counterclockwise rotation around the x-axis was performed. Figure 4 In (d), there is no rotation about the y-axis and about the z-axis.

[0138] S35, translating the crack center of the rotated crack model with a rough surface back from the origin to the starting point.

[0139] In a specific embodiment, the three-dimensional crack surface is initially assumed to be a disk, because the crack is initially approximately circular or elliptical when it is generated, and as the fracture process continues, its shape becomes relatively irregular due to various restrictions such as the layer. Therefore, the perfect ellipse does not conform to the shape of the crack contour in reality, and the present invention uses a one-dimensional random rough surface to characterize the crack contour. Figure 6 The evolution diagram of the crack contour characterization process shows the specific process of crack contour characterization: the first step is to generate Figure 6 The two one-dimensional random rough surfaces shown in (a) are used to depict the upper and lower contours of the ellipse respectively; the second step is based on Figure 6 (b) shows the ellipse profile. Two random rough surfaces are superimposed on the upper and lower sides of the ellipse in proportion to obtain the following: Figure 6 (c) shows the new ellipse outline; the third step is to make a judgment based on the new ellipse outline. When the new ellipse outline is within the original ellipse outline, the new ellipse outline is retained, otherwise the original ellipse outline is retained, and finally the following is generated: Figure 6 (d) Crack profile shown.

[0140] Figure 7 This is a diagram of crack changes at different roughness levels. Figure 7 (a) is the case when the correlation length is fixed and the RMS height increases; Figure 7 (b) is the case where the correlation length is fixed and the RMS height becomes smaller; Figure 7 (c) is the case when the RMS height is fixed and the correlation length becomes larger; Figure 7 (d) is the case when the RMS height is constant and the correlation length becomes smaller. Figure 4 (c) and Figure 7 By comparison, we can observe the change of crack roughness when the rough surface parameters change. x and l y When fixed, the larger the RMS height δ2, the rougher the surface ( Figure 7(a)), whereas a smaller RMS height δ2 means a smoother surface ( Figure 7 (b)). When the RMS height δ2 is fixed, the correlation length l x and l y The smaller the surface, the rougher the corresponding direction. Figure 7 (c)), whereas the correlation length l x or y The larger the value, the smoother the surface is ( Figure 7 (d)). Therefore, the cracks based on the random rough surface can be expressed by the root mean square height δ2, the correlation length l x or y The parameters such as surface roughness can be used to describe the roughness of the crack, and then the roughness characteristics of the crack can be quantitatively studied.

[0141] S4. Perform numerical simulation of crack detection based on the crack model with spatial morphology.

[0142] The crack model with spatial morphology is constructed by the above method, and the crack model is used as a numerical model to carry out numerical simulation research on crack detection. The method selected for crack detection is borehole radar, and the numerical simulation method is the finite difference time domain method. Borehole radar is a special form of ground penetrating radar. Since its antenna is located in the borehole, it can be closer to the detection target and avoid the influence of the near-surface weathering layer. The finite difference time domain method is to perform differential discretization based on the differential form of Maxwell's equations to obtain a set of time domain advancement formulas.

[0143] In order to perform finite-difference time-domain calculations, it is necessary to perform a step-by-step approximation on the irregular shape to make it conform to an orthogonal grid. This process is also called discretization. Figure 4 Taking the crack model in (d) as an example, the effect after discretization is as follows Figure 8 shown. Figure 8 (a) with Figure 4 (d) The same, placed here for easy observation; Figure 8 (b) is the result after the crack model is discretized (grid size 0.1m); Figure 8 (c) The locations of cracks and holes in the simulation area.

[0144] The simulation area is 8m×8m×16m, and the borehole is located at x=4m, y=1.5m. Figure 8 (c) Slice along the plane x = 4m and the slice image is Fig. 9. The cracks are filled with air, with a dielectric constant of ε0 and a conductivity of 0. The dielectric constant of the surrounding rock is 4ε0, and the conductivity is 0.001S / m. The embodiment of the present invention mainly studies the response relationship between waves and media, so the borehole and antenna are not actually modeled. The excitation source selects the Ricker wavelet, with a center frequency of f0=100Mhz, a grid size of Δx=Δy=Δz=0.1m, a number of grids in the simulation area of ​​80×80×160, and a time step of 0.16677ns. The transmitting point is initially located at 2.8m in the borehole, and the receiving point is located below the transmitting point, 1.6m apart. During measurement, the transmitting point and the receiving point move upward at the same time, 0.2m each time, for a total of 60 times. Since each channel of the borehole radar measurement is independent of each other, parallel computing can be easily implemented. OpenMP is used to implement parallel computing, thereby making full use of the computer's computing resources and improving computing efficiency. The final crack simulation results are shown in Fig.10 .

[0145] like Fig.11 As shown, the present invention provides a three-dimensional monomer rough crack modeling system 100, comprising:

[0146] The contour processing module 110 is used to perform contour processing on a preset three-dimensional crack basic shape by using a one-dimensional random rough surface generation function to obtain a crack model with an irregular contour.

[0147] The surface processing module 120 is used to perform surface processing on the irregular-contour crack model by using a two-dimensional random rough surface generation function to obtain a crack model with a rough surface.

[0148] The space transformation module 130 is used to perform space transformation on the crack model with a rough surface to obtain a crack model with a spatial form.

[0149] The numerical simulation module 140 is used to perform numerical simulation of crack detection based on the crack model with spatial morphology.

[0150] Since the system / device described in the above embodiments of the present invention is a system / device used to implement the method of the above embodiments of the present invention, a person skilled in the art can understand the specific structure and deformation of the system / device based on the method described in the above embodiments of the present invention, and thus will not be described in detail here. All systems / devices used in the method of the above embodiments of the present invention belong to the scope of protection of the present invention.

[0151] In addition, an embodiment of the present invention also provides a three-dimensional monomer rough crack modeling device, including: at least one database; and a memory communicatively connected to the at least one database; wherein the memory stores instructions that can be executed by at least one database, and the instructions are executed by at least one database so that the at least one database can execute a three-dimensional monomer rough crack modeling method as described above.

[0152] Furthermore, an embodiment of the present invention provides a computer-readable medium having computer executable instructions stored thereon, and when the executable instructions are executed by a processor, a three-dimensional monomer rough crack modeling method as described above is implemented.

[0153] In summary, the present invention discloses a three-dimensional monomer rough crack modeling method, system and medium, and the present invention mainly includes: (1) constructing the basic shape of the crack; wherein the basic shape can select a three-dimensional simple shape, preferably an ellipsoid as the basic shape of the crack; (2) crack contour processing; wherein, according to the basic shape selected in step (1), the xoy surface contour of the crack is characterized to obtain a crack model with an irregular contour. (3) crack surface processing; wherein, based on the crack obtained in step (2), the crack is surface processed to obtain a crack with a rough surface. (4) spatial transformation; wherein, according to the crack obtained in step (3), the crack is spatially transformed to obtain a crack with a spatial form.

[0154] Based on the above description, it can be seen that the crack model obtained by the modeling method of the present invention can simultaneously reflect the characteristics of roughness, pinch-out, irregularity, etc., and provide a reliable numerical model for subsequent crack numerical simulation research.

[0155] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0156] The present invention is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems) and computer program products according to the embodiments of the present invention. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions.

[0157] It should be noted that in the claims, any reference numerals placed between brackets shall not be construed as limiting the claims. The word "comprising" does not exclude the presence of components or steps not listed in the claims. The word "a" or "an" preceding a component does not exclude the presence of a plurality of such components. The invention may be implemented by means of hardware comprising several different components and by means of a suitably programmed computer. In the claims enumerating several means, several of these means may be embodied by the same hardware. The use of the words first, second, third, etc., is for convenience of expression only and does not indicate any order. These words may be understood as part of the component name.

[0158] In addition, it should be noted that, in the description of this specification, the description of the terms "one embodiment", "some embodiments", "embodiment", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0159] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments after knowing the basic creative concept. Therefore, the claims should be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present invention.

[0160] Obviously, those skilled in the art can make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention should also include these modifications and variations.

Claims

1. A three-dimensional monomer rough crack modeling method, characterized in that: The method comprises: The preset three-dimensional crack basic shape is processed by a one-dimensional random rough surface generation function to obtain a crack model with an irregular contour, including: based on a one-dimensional random rough surface generation function of a Gaussian spectrum, obtaining two one-dimensional random rough surfaces for respectively describing the upper and lower contours of the xoy surface of the crack basic shape; superimposing two one-dimensional random rough surfaces on the upper and lower contours of the crack according to a first ratio to obtain a new crack contour; making a judgment based on the new crack contour and the crack basic shape; if the new crack contour is included in the crack basic shape, retaining the new crack contour to obtain a crack model with an irregular contour; if the new crack contour is not included in the crack basic shape, retaining the contour of the crack basic shape to obtain an irregular crack model; wherein the one-dimensional random rough surface for describing the upper contour of the xoy surface of the crack basic shape has a different value from the one-dimensional random rough surface for describing the lower contour of the xoy surface of the crack basic shape, and the three-dimensional crack basic shape is an ellipsoid; The surface of the irregular-contour crack model is processed by a two-dimensional random rough surface generation function to obtain a crack model with a rough surface, including: obtaining two two-dimensional random rough surfaces respectively used to describe the upper and lower surfaces of the irregular-contour crack model based on a two-dimensional random rough surface generation function of a Gaussian spectrum; superimposing two two-dimensional random rough surfaces on the upper and lower surfaces of the irregular-contour crack model according to a second ratio to obtain a new crack surface; wherein the two-dimensional random rough surface used to describe the upper surface of the irregular-contour crack model has a different value from the two-dimensional random rough surface used to describe the lower surface of the irregular-contour crack model; Performing spatial transformation on the crack model with a rough surface to obtain a crack model with a spatial form; A numerical simulation of crack detection is performed based on the crack model with spatial morphology.

2. A three-dimensional monomer rough crack modeling method as claimed in claim 1, characterized in that: The ellipsoid satisfies: Among them, a>b>c, a is the length of the major semiaxis, b is the length of the middle semiaxis, and c is the length of the minor semiaxis; a and b affect the contour of the xoy surface of the ellipsoid, and c is in the z direction of the ellipsoid; twice the minor semiaxis c is the crack thickness.

3. A three-dimensional monomer rough crack modeling method as claimed in claim 1, characterized in that: The one-dimensional random rough surface generation function based on Gaussian spectrum is: Among them, x n =nΔx (n = -N / 2+1, ..., N / 2) represents the nth sampling point on a one-dimensional random rough surface, L is the generation length, N is the number of equally spaced discrete points, Δx is the distance between two adjacent points, F(k j ) and f(x n ) is called the Fourier transform pair and is defined as: In which, the discrete wave number k is defined j The expression for k j =2πj / L, S(k j ) is the power spectral density of a one-dimensional random rough surface, N(0,1) represents a normally distributed random number with a mean of 0 and a variance of 1; The power spectral density of the one-dimensional random rough surface is: Where δ1 is the average root height of the one-dimensional rough surface; l is the correlation length; The first ratio is: and c =and b +y b ·and a / n Among them, y c is the crack contour after superposition, y b is the upper contour of the crack before superposition, y a is a one-dimensional random rough surface used to describe the upper contour of the xoy surface of the basic shape of the crack, n is a scale factor, and the scale factor n can be taken to y b The maximum value of .

4. A three-dimensional monomer rough crack modeling method as claimed in claim 1, characterized in that: The two-dimensional random rough surface generation function based on Gaussian spectrum is: where x m =mΔx(m=-M / 2+1,…,M / 2), y n =nΔy (n = -N / 2+1, ..., N / 2) represent the mth sampling point in the x direction and the nth sampling point in the y direction on the two-dimensional random rough surface, respectively. x and L y are the generated lengths in the x and y directions, respectively; M and N are the number of equally spaced discrete points in the x and y directions, respectively; Δx and Δy are the distances between two adjacent points in the x and y directions, respectively; With f(x m ,y n ) is called the Fourier transform pair and is defined as: The discrete wave number is defined as and The expressions are is the power spectral density of the two-dimensional random rough surface; The power spectral density of the two-dimensional random rough surface is: Where δ2 is the root mean square height of the two-dimensional rough surface; l x and l y are the correlation lengths along the x and y directions, respectively; The second ratio is: With c =from b +with b ·With a / m Among them, z c is the upper surface of the crack after superposition, z b is the upper surface of the crack before superposition, z a is a two-dimensional random rough surface used to characterize the upper surface of the crack, m is a scale factor, and the scale factor m can be taken to z b The maximum value of .

5. A three-dimensional monomer rough crack modeling method as claimed in claim 4, characterized in that: The crack model with a rough surface is spatially transformed to obtain a crack model with a spatial form, including: Add corresponding translation parameters in the XYZ directions of the crack model with a rough surface; Translating the crack center of the crack model with a rough surface from the starting point to the origin; The crack model with a rough surface is rotated around the x-axis, the y-axis and the z-axis respectively; The crack center of the rotated crack model with rough surface is translated back from the origin to the starting point; The translation parameters include an x ​​translation amount, a y translation amount, and a z translation amount.

6. A three-dimensional monomer rough crack modeling system, characterized in that: include: A contour processing module, used for contour processing of a preset three-dimensional crack basic shape through a one-dimensional random rough surface generation function to obtain a crack model with an irregular contour, including: based on a one-dimensional random rough surface generation function of a Gaussian spectrum, obtaining two one-dimensional random rough surfaces for respectively describing the upper and lower contours of the xoy surface of the crack basic shape; superimposing two one-dimensional random rough surfaces on the upper and lower contours of the crack according to a first ratio to obtain a new crack contour; making a judgment based on the new crack contour and the crack basic shape; if the new crack contour is included in the crack basic shape, retaining the new crack contour to obtain a crack model with an irregular contour; if the new crack contour is not included in the crack basic shape, retaining the contour of the crack basic shape to obtain an irregular crack model; wherein the one-dimensional random rough surface for describing the upper contour of the xoy surface of the crack basic shape has a different value from the one-dimensional random rough surface for describing the lower contour of the xoy surface of the crack basic shape, and the three-dimensional crack basic shape is an ellipsoid; A surface processing module, used for performing surface processing on the irregular-contour crack model through a two-dimensional random rough surface generation function to obtain a crack model with a rough surface, comprising: obtaining two two-dimensional random rough surfaces respectively used to depict the upper and lower surfaces of the irregular-contour crack model based on a two-dimensional random rough surface generation function of a Gaussian spectrum; superimposing two two-dimensional random rough surfaces on the upper and lower surfaces of the irregular-contour crack model according to a second ratio to obtain a new crack surface; wherein the two-dimensional random rough surface used to depict the upper surface of the irregular-contour crack model has a different value from the two-dimensional random rough surface used to depict the lower surface of the irregular-contour crack model; A spatial transformation module, used for performing spatial transformation on the crack model with a rough surface to obtain a crack model with a spatial form; The numerical simulation module is used to perform numerical simulation of crack detection based on the crack model with spatial morphology.

7. A three-dimensional monomer rough crack modeling device, characterized in that: include: at least one database; and a memory in communication with the at least one database; The memory stores instructions that can be executed by the at least one database, and the instructions are executed by the at least one database so that the at least one database can execute the three-dimensional monomer rough crack modeling method as described in any one of claims 1-5.

8. A computer-readable medium having computer-executable instructions stored thereon, characterized in that: When the executable instructions are executed by the processor, a three-dimensional monomer rough crack modeling method as described in any one of claims 1 to 5 is implemented.

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