A two-dimensional numerical modeling method for porous materials

Abstract

This invention provides a two-dimensional numerical modeling method for porous materials, using C++ as the underlying code and Javascript as the scripting language. It can not only model any number and shape of holes, but also accurately set the size parameters of the holes to follow a specific distribution function (such as uniform distribution, normal distribution, and Weiber distribution). Subsequently, the two-dimensional numerical computation mesh is obtained using Gmsh mesh generation software. This invention provides researchers and engineers with a method to quickly obtain two-dimensional numerical meshes for porous materials, and accurately set the number, shape characteristics, and spatial location of the holes, applicable to fields such as numerical calculations of porous materials. The modeling method of this invention can not only easily and quickly construct two-dimensional numerical models based on the actual size parameters of the holes, but also easily and quickly construct two-dimensional numerical models of porous materials based on certain distribution characteristics.

Description

Technical Field

[0001] This invention belongs to the field of porous materials technology and relates to numerical calculation, specifically to a two-dimensional numerical modeling method for porous materials. Background Technology

[0002] Porous materials (rock, concrete, etc.) are widely found in national defense engineering, infrastructure engineering, and mining engineering. Rock can be considered a natural material composed of mineral particles and cementing substances formed under long-term geological processes, and related indoor observations indicate that a large number of micropores exist within rocks. Concrete is an artificial material composed of cement and sand, and related indoor observations also show that a large number of micropores exist within concrete. Under external loads, stress concentration occurs near these micropores, leading to the initiation and propagation of cracks. Current research indicates that micropores within materials have a significant impact on the material's constitutive characteristics and mechanical parameters.

[0003] To investigate the impact of micropores on the constitutive characteristics and mechanical parameters of materials, researchers have begun to conduct studies based on numerical simulations. Preprocessing is a crucial step in numerical simulations, but currently there is no simple and effective method to obtain two-dimensional numerical models of porous materials. On the one hand, it is impossible to perform rapid batch modeling of a large number of pores; on the other hand, it is impossible to easily and quickly set the size and spatial location parameters of the pores. This not only results in a significant amount of time being spent on preprocessing, but also in the fact that the constructed two-dimensional numerical models cannot accurately reflect the micropore characteristics of the material. Therefore, it is necessary to establish a simple and effective method for modeling two-dimensional numerical models of porous materials. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a two-dimensional numerical modeling method for porous materials, thereby solving the technical problem of long preprocessing time required for numerical calculations in existing technologies.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] A two-dimensional numerical modeling method for porous materials, comprising the following steps:

[0007] Step 1: Based on indoor observation methods, obtain the total number N of holes inside the object under study that need to be characterized in the modeling stage;

[0008] Step 2: For the N holes inside the object under study, based on the shape characteristics of the holes, an approximate method is used to classify the holes into five shapes: triangles, rectangles, polygons, circles, and ellipses, and the number N of each shape is obtained. i ;

[0009] Step 3: For the five types of holes—triangles, rectangles, polygons, circles, and ellipses—obtain the size parameters for each hole.

[0010] Step 4: For the five types of holes—triangles, rectangles, polygons, circles, and ellipses—if the exact size parameters of each hole cannot be obtained, but it is known that the size parameters of the holes follow one of the uniform distribution type, normal distribution type, and Weibull distribution type, then the size parameters of each hole can be obtained by setting the parameters of this distribution type.

[0011] In step 4, the dimensional parameter L is calculated as follows:

[0012] For a uniform distribution: L = L min +(L max -L min )α;

[0013] For the Weibull distribution:

[0014] For the normal distribution:

[0015] In the formula:

[0016] α is a random value uniformly distributed in the interval [0, 1].

[0017] L min This represents the lower limit value of the dimensional parameter;

[0018] L max This represents the upper limit of the dimensional parameter;

[0019] λ is the scaling parameter;

[0020] k is a shape parameter;

[0021] μ is the mean;

[0022] σ is the standard deviation;

[0023] Step 5: For the five types of holes—triangles, rectangles, polygons, circles, and ellipses—obtain the spatial position parameters for each hole.

[0024] The spatial position parameters include the coordinate value x in the X direction and the coordinate value y in the Y direction;

[0025] Step 6: First, establish a two-dimensional geometric model of the entire object under study without considering holes. The outer contour of this geometric model can be any irregular or regular shape.

[0026] Step 7: Based on the number, size, and spatial location parameters of the holes obtained in Steps 2, 3, 4, and 5, use Javascript scripting language and iterative loops to build the geometric model of each hole within the two-dimensional geometric model of the entire object under study.

[0027] Step 8: After the geometric model of all the holes is established, the two-dimensional geometric modeling of the material containing holes is completed; then, the geometric data is output as a geo file according to the format type.

[0028] Step 9: Import the geo file into the Gmsh mesh generation software. Using the 2D mesh generation function, you will obtain a two-dimensional numerical model of the porous material.

[0029] The present invention also has the following technical features:

[0030] In step 1, the indoor observation methods include capillary pressure curve method, CT scanning technology, scanning electron microscopy and nuclear magnetic resonance technology.

[0031] In step 3, for the triangular hole, the dimensional parameters include the length l of each side. i For rectangular holes, the dimensional parameters include length a. i and width b i For polygonal holes, the dimensional parameters include the length l of each side. i For circular holes, the dimensional parameters include radius r. i For elliptical holes, the dimensional parameters include the major semi-axis a. i and short half-axis b i .

[0032] In step 5, if the spatial location parameters of each hole cannot be accurately obtained, the spatial location parameters are set in a randomized manner; it is possible to set the spatial location parameters of the holes to be randomly distributed throughout the entire model, or to set the holes to be randomly distributed in a local area of ​​the model.

[0033] The coordinate values ​​x and y are calculated as follows:

[0034] In the formula:

[0035] α represents a random value uniformly distributed in the interval [0, 1].

[0036] X min This represents the lower limit of the X-axis coordinate value.

[0037] X max This represents the upper limit of the X-axis coordinate value.

[0038] Y minThis represents the lower limit of the Y-axis coordinate value.

[0039] Y max This represents the upper limit of the Y-axis coordinate value.

[0040] In step 6, the regular shapes include triangles, rectangles, circles, and ellipses.

[0041] In step 8, the format types include four main categories: Point, Line, LineLoop, and Surface.

[0042] Compared with the prior art, the present invention has the following technical effects:

[0043] (I) The modeling method of the present invention can not only quickly and easily construct a two-dimensional numerical model based on the actual size parameters of the holes, but also quickly and easily construct a two-dimensional numerical model of a porous material based on a certain distribution characteristic.

[0044] (II) The modeling method of the present invention can not only greatly reduce the time of the preprocessing part in the numerical calculation process, but also characterize the complex pore distribution characteristics in the two-dimensional numerical model, laying the foundation for studying the failure process of porous materials under external load.

[0045] (III) The modeling method of this invention can be applied to fields such as numerical calculation of porous materials. This invention provides researchers and engineers with a method for quickly obtaining two-dimensional numerical models of porous materials, and enables accurate setting of the number, shape characteristics, and spatial location of pores during the modeling process. Attached Figure Description

[0046] Figure 1 This is a flowchart of the two-dimensional numerical modeling method for porous materials according to the present invention.

[0047] Figure 2 This is a schematic diagram of a two-dimensional model of the porous material of the present invention.

[0048] Figure 3 This is a schematic diagram of the geometric model of the two-dimensional porous material of the present invention.

[0049] Figure 4 This is a schematic diagram of a two-dimensional porous material mesh model according to the present invention. Figure 4 (a) in the diagram is a schematic diagram of the overall mesh model. Figure 4 (b) in the diagram is a schematic diagram of the local mesh model.

[0050] The specific content of the present invention will be further explained in detail below with reference to the embodiments. Detailed Implementation

[0051] It should be noted that, unless otherwise specified, all models and parameters in this invention are based on models and parameters known in the prior art.

[0052] Currently, there is no simple and effective method to quickly construct the internal pores of materials containing several pores (such as rock and concrete), resulting in a significant time consumption in the preprocessing work for numerical calculations. To address this issue, this invention proposes a two-dimensional numerical modeling method for porous materials.

[0053] Reference Figure 2 To establish a two-dimensional numerical model of porous materials, this invention utilizes the C++ and Javascript programming languages ​​and employs a parametric modeling method to model any number and shape of pores.

[0054] The method of this invention uses C++ as the underlying code and Javascript as the scripting language. It can not only model any number and shape of holes, but also accurately set the size parameters of the holes to follow a specific distribution function (such as uniform distribution, normal distribution, and Weiber distribution). Subsequently, a two-dimensional numerical computation mesh is obtained using Gmsh mesh generation software. This invention provides researchers and engineers with a method for rapidly obtaining two-dimensional numerical meshes for porous materials, and accurately setting the number, shape characteristics, and spatial location of the holes. It can be used in fields such as numerical computation of porous materials.

[0055] The following are specific embodiments of the present invention. It should be noted that the present invention is not limited to the following specific embodiments. All equivalent modifications made based on the technical solutions of this application fall within the protection scope of the present invention.

[0056] Example:

[0057] This embodiment presents a two-dimensional numerical modeling method for porous materials, such as... Figure 1 As shown, the method includes the following steps:

[0058] Step 1: Based on indoor observation methods, obtain the total number N of holes inside the object under study that need to be characterized in the modeling stage;

[0059] In step 1, the indoor observation methods include capillary pressure curve method, CT scan technology, scanning electron microscopy, and nuclear magnetic resonance technology. All of these indoor observation methods are known and commonly used techniques.

[0060] Step 2: For the N holes inside the object under study, based on the shape characteristics of the holes, an approximate method is used, such as... Figure 2 As shown, the holes are divided into five shapes: triangles, rectangles, polygons, circles, and ellipses, and the number N of holes for each shape is obtained.i ;

[0061] Step 3: For the five types of holes—triangles, rectangles, polygons, circles, and ellipses—obtain the size parameters for each hole.

[0062] In step 3, for the triangular hole, the dimensional parameters include the length l of each side. i For rectangular holes, the dimensional parameters include length a. i and width b i For polygonal holes, the dimensional parameters include the length l of each side. i For circular holes, the dimensional parameters include radius r. i For elliptical holes, the dimensional parameters include the major semi-axis a. i and short half-axis b i .

[0063] Step 4: For the five types of holes—triangles, rectangles, polygons, circles, and ellipses—if the exact size parameters of each hole cannot be obtained, but it is known that the size parameters of the holes follow one of the uniform distribution type, normal distribution type, and Weibull distribution type, then the size parameters of each hole can be obtained by setting the parameters of this distribution type.

[0064] In step 4, for a uniform distribution, a lower limit value L needs to be set for the dimensional parameters to conform to a uniform distribution. min and upper limit value L max For the Weiber distribution, the scaling parameter λ and shape parameter k need to be set when the size parameters follow the Weiber distribution; for the normal distribution, the mean μ and standard deviation σ need to be set when the size parameters follow the normal distribution.

[0065] In step 4, the dimensional parameter L is calculated as follows:

[0066] For a uniform distribution: L = L min +(L max -L min )α;

[0067] For the Weibull distribution:

[0068] For the normal distribution:

[0069] In the formula:

[0070] α is a random value uniformly distributed in the interval [0, 1].

[0071] L min This represents the lower limit value of the dimensional parameter;

[0072] L max This represents the upper limit of the dimensional parameter;

[0073] λ is the scaling parameter;

[0074] k is a shape parameter;

[0075] μ is the mean;

[0076] σ is the standard deviation.

[0077] Step 5: For the five types of holes—triangles, rectangles, polygons, circles, and ellipses—obtain the spatial position parameters for each hole.

[0078] The spatial position parameters include the coordinate value x in the X direction and the coordinate value y in the Y direction.

[0079] In step 5, if the spatial location parameters of each hole cannot be accurately obtained, a randomized approach is adopted to set the spatial location parameters; this can be done either by setting the spatial location parameters of the holes to be randomly distributed throughout the entire model or by setting the holes to be randomly distributed in local areas of the model.

[0080] The coordinate values ​​x and y are calculated as follows:

[0081] In the formula:

[0082] α represents a random value uniformly distributed in the interval [0, 1].

[0083] X min This represents the lower limit of the X-axis coordinate value.

[0084] X max This represents the upper limit of the X-axis coordinate value.

[0085] Y min This represents the lower limit of the Y-axis coordinate value.

[0086] Y max This represents the upper limit of the Y-axis coordinate value.

[0087] Step 6: First, establish a two-dimensional geometric model of the entire object under study without considering holes. The outer contour of this geometric model can be any irregular or regular shape.

[0088] In step 6, the regular shapes include triangles, rectangles, circles, and ellipses.

[0089] In this step, the specific process of establishing the two-dimensional geometric model can be the same as the known and commonly used process for establishing two-dimensional geometric models.

[0090] Step 7: Based on the number, size, and spatial location parameters of the holes obtained in Steps 2, 3, 4, and 5, use JavaScript to iteratively build the geometric model of each hole within the entire two-dimensional geometric model of the object under study. For example... Figure 3 As shown;

[0091] In this step, the specific process of establishing the geometric model of the hole can be the same as the known and commonly used process of establishing the geometric model of the hole.

[0092] Step 8: After the geometric model of all the holes is established, the two-dimensional geometric modeling of the material containing holes is completed; then, the geometric data is output as a geo file according to the format type.

[0093] In step 8, the format types include four main categories: Point, Line, LineLoop, and Surface.

[0094] Step 9: Import the geo file into the Gmsh mesh generation software. Using the 2D mesh generation function, a two-dimensional numerical model of the porous material is obtained, such as... Figure 4 As shown in the image. Then, commonly used numerical simulation software can be imported to perform numerical simulations.

Claims

1. A method of modeling a two-dimensional numerical model of a porous material, the method comprising: The method comprises the following steps: Step 1, based on indoor observation means, obtaining the total number N of holes inside the object to be studied which need to be characterized in the modeling stage; Step 2, for N holes inside the object to be studied, according to the shape characteristics of the holes, the holes are divided into five types of holes of triangle, rectangle, polygon, circle and ellipse by using an approximate method, and the number N of holes of each type is obtained i ; Step 3, for the five types of holes of triangle, rectangle, polygon, circle and ellipse, the size parameters of each hole are obtained respectively; Step 4, for the five types of holes of triangle, rectangle, polygon, circle and ellipse, if the accurate size parameters of each hole cannot be obtained, but it is known that the size parameters of the holes are subject to one of the uniform distribution type, normal distribution type and Weibull distribution type, then the size parameters of each hole are obtained by setting the parameters of this distribution type; In step 4, the calculation of the size parameter L is: For uniform distribution: L = L min + (L max - L min )α; For the Weibull distribution: For normal distribution: In the formula: α is a random value uniformly distributed in the interval [0, 1]; L min is the lower limit value for the dimension parameter; L max is an upper limit value for the dimension parameter; λ is the proportion parameter; k is the shape parameter; μ is the mean value; σ is the standard deviation; Step 5, for the five types of holes of triangle, rectangle, polygon, circle and ellipse, the spatial position parameters of each hole are obtained respectively; The spatial position parameters include the coordinate value x in the X direction and the coordinate value y in the Y direction; Step 6, first, a two-dimensional geometric model of the entire object to be studied without considering the holes is established, and the outer contour line of the geometric model can be an arbitrary irregular shape or a regular shape; Step 7, according to the number of holes, size parameters and spatial position parameters obtained in steps 2, 3, 4 and 5, the geometric model of each hole is established inside the two-dimensional geometric model of the entire object to be studied by using the Javascript script language and the method of loop iteration; Step 8, after the geometric models of all holes are established, the two-dimensional geometric modeling of the material containing holes is completed; then the geometric data is output as a file in the geo file format according to the format type; Step 9, the file in the geo file format is imported into the Gmsh mesh division software, and the two-dimensional mesh division function is used to obtain the two-dimensional numerical model of the material containing holes.

2. The method of claim 1, wherein, In step 1, the indoor observation means include capillary pressure curve method, CT scanning technology, scanning electron microscope method and nuclear magnetic resonance technology.

3. The method of claim 1, wherein, In Step 3, for a triangular hole, the size parameters include the length of each side, l i ; for a rectangular hole, the size parameters include the length, a i , and the width, b i ; for a polygonal hole, the size parameters include the length of each side, l i ; for a circular hole, the size parameters include the radius, r i ; and for an elliptical hole, the size parameters include the major axis, a i , and the minor axis, b i .

4. The method of claim 1, wherein, In step 5, if the spatial position parameters of each hole cannot be accurately obtained, a randomized way is adopted to set the spatial position parameters; both the random distribution of the spatial position parameters of the holes in the entire model and the random distribution of the holes in the local area of the model can be set; The calculation of the coordinate values x and y is: In the formula: α represents a random value uniformly distributed in the interval [0, 1]; X min is a lower limit value of the X-direction coordinate value; X max is an upper limit value of the X-direction coordinate value; Y min is a lower limit value of the Y-direction coordinate value; Y max is an upper limit value of the Y-direction coordinate value.

5. The method of claim 1, wherein, In step 6, the regular shape includes triangle, rectangle, circle and ellipse.

6. The method of claim 1, wherein, In step 8, the format type includes four major format types of Point, Line, LineLoop and Surface.

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