Method for generating two-dimensional circular element model of complex morphology materials containing holes and cracks

Abstract

The application discloses a kind of complex topography material two-dimensional circle unit model generation methods containing hole and fissure, comprising the following steps: based on Boolean operation, draw two-dimensional complex topography material model containing hole and fissure;Set circle unit parameter, generate initial circle unit in two-dimensional complex topography material model, obtain initial two-dimensional circle unit model;Based on circle unit non-continuous deformation analysis method, calculate circle unit displacement increment by enlarging circle unit, update circle unit position, repeat operation until the radius of all circle units reaches the preset radius range;Continuously calculate circle unit displacement increment and update circle unit position, obtain final two-dimensional circle unit model.The application can quickly generate specified circle unit packing density, the distribution form and range of circle unit radius, contain any hole and fissure, and have complex boundary high-quality two-dimensional circle unit model.The principle of the method of the application is simple, and the calculation is efficient, which can significantly reduce the numerical simulation modeling cost of circle unit.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of computational mechanics and material modeling, and particularly relates to a two-dimensional circular element model generation method for a material with complex morphology containing holes and cracks. BACKGROUND

[0002] At present, discrete element and non-continuous deformation analysis methods using circular elements as basic calculation elements are increasingly mature, and they are often used to simulate the mechanical failure behavior of materials. The accuracy of the simulation results of such numerical methods is often affected by the distribution of the radii of the circular elements, the radii of the circular elements and the density of the circular elements, so it is crucial to generate high-quality two-dimensional circular element models.

[0003] However, existing modeling methods, such as the "rainfall method", can only generate models with simple geometric shapes such as squares and circles; the "extrusion method" can generate relatively complex models, but cannot generate models containing complex holes, and the above modeling methods are low in efficiency, complex in modeling process, and can make the coordination number of the model in some directions dominant; the "triangular mesh generation method" can quickly generate relatively complex models, but has the problems of uneven distribution of circular elements and difficulty in controlling the density of circular elements, and cannot generate models containing cracks. Therefore, how to quickly generate high-quality two-dimensional circular element models with complex shapes and containing holes and small cracks inside is a major challenge for such numerical methods. SUMMARY

[0004] The purpose of the present application is to overcome the shortcomings of the prior art and provide a two-dimensional circular element model generation method for a material with complex morphology containing holes and cracks.

[0005] The present application provides a two-dimensional circular element model generation method for a material with complex morphology containing holes and cracks, comprising the following steps:

[0006] S1. Based on Boolean operation, draw a two-dimensional complex morphology material model containing holes and cracks;

[0007] S2. Set the circular element parameters to generate initial circular elements in the two-dimensional complex morphology material model to obtain an initial two-dimensional circular element model;

[0008] S3. Based on the non-continuous deformation analysis method of circular elements, calculate the displacement increment of the circular elements by enlarging the circular elements, update the position of the circular elements, and repeat the operations of circular element enlargement and circular element position adjustment until the radii of all circular elements reach the preset radius range;

[0009] S4. Based on the non-continuous deformation analysis method of circular elements, continuously calculate the displacement increment of the circular elements and update the position of the circular elements until the displacement increment calculated in a single time step is lower than the preset threshold value to obtain the final two-dimensional circular element model.

[0010] In step S1, the preset two-dimensional complex topography material is discretized into basic geometric figures, and a two-dimensional complex topography material model is obtained through Boolean operation; the preset two-dimensional complex topography material is a complex topography material containing holes and cracks.

[0011] In step S1, the preset two-dimensional complex topography material is discretized into basic geometric figures, and a two-dimensional complex topography material model is obtained through Boolean operation; the preset two-dimensional complex topography material is a complex topography material containing holes and cracks.

[0012] Step S2 includes the following steps:

[0013] Setting the circular unit parameters;

[0014] Calculating the area of the two-dimensional complex topography material model;

[0015] According to the area of the two-dimensional complex topography material model and the circular unit parameters, a set of circular unit radii is generated;

[0016] Taking points in the model as the initial center positions of the circular units, and generating circular units at the initial center positions of the circular units with the set of circular unit radii obtained, a set of circular units is obtained;

[0017] Continuously reducing the circular unit radii of the set of circular units obtained in a proportion, until all the circular units are not embedded with each other, and the circular units are not embedded with cracks, holes and model boundaries, and finally the set of circular units obtained and the two-dimensional complex topography material model are taken as the initial two-dimensional circular unit model.

[0018] Step S2 specifically includes the following steps:

[0019] Setting the circular unit density, the circular unit radius distribution form and the circular unit radius range;

[0020] Calculating the area of the two-dimensional complex topography material model;

[0021] According to the area of the two-dimensional complex topography material model and the circular unit density, the total area of the circular units is obtained, and a set of circular unit radii is continuously generated until the sum of the areas of the circular units calculated based on the set of circular unit radii reaches the total area of the circular units;

[0022] Uniformly scattering points in the model as the initial center positions of the circular units, and then generating circular units at the initial center positions of the circular units with the set of circular unit radii obtained, a set of circular units is obtained;

[0023] The circular unit radius of a group of circular units is continuously reduced proportionally until all circular units are not embedded in each other, there is no embedding between the circular units and the cracks, and there is no embedding between the circular units and the model boundary. The final circular unit set and the two-dimensional complex morphology material model are used as the initial two-dimensional circular unit model.

[0024] The circular unit parameters include circular unit density, circular unit radius distribution form, and circular unit radius range; the circular unit density is the ratio of the total area of ​​all circular units in the model to the model area; the circular unit radius distribution forms include equal diameter distribution, uniform distribution, normal distribution, power law distribution, and custom circular unit gradation; specific requirements for determining the circular unit radius range are: when the circular unit radius distribution form is equal diameter distribution, a single circular unit radius value is required to determine the circular unit radius range; when the circular unit radius distribution form is uniform distribution, determining the circular unit radius range requires determining the maximum and minimum radius of the circular unit; when the circular unit radius distribution form is normal distribution, determining the circular unit radius range requires determining the circular unit radius mean, standard deviation, maximum and minimum radius; when the circular unit radius distribution form is power law distribution, determining the circular unit radius range requires determining the power exponent, the maximum and minimum radius of the circular unit; when the circular unit radius distribution form is custom circular unit gradation, determining the circular unit radius range requires determining the radius and proportion of each circular unit.

[0025] Step S3 is specifically as follows:

[0026] Continue to proportionally enlarge the circular elements in the initial two-dimensional circular element model obtained in step S2 until the radius of all circular elements reaches the circular element radius range set in step S2; during the enlargement process, when any circular elements or the circular elements and the model contour lines overlap, the displacement increment of the circular elements is calculated based on the circular element discontinuous deformation analysis method and the circular element position is updated before the next proportional enlargement.

[0027] The calculation of the displacement increment of the circular element based on the circular element discontinuous deformation analysis method specifically includes the following steps:

[0028] First, construct the total equilibrium equation for the circular unit system with enlarged radius, and use the following formula to express it: Among them, when hour, is the interaction stiffness submatrix between circular element i and circular element j, and the interaction stiffness submatrix is matrix; is the radius correlation matrix of circular unit i, and the radius correlation matrix is matrix; is the unknown quantum matrix of the displacement of circular unit i, denoted as ,in For circular unit i xdirectional displacement, is the directional displacement of the circular element i in y directional displacement; is the generalized force vector of the circular element i, denoted as , where is the directional force of the circular element i in x directional force, is the directional force of the circular element i in y directional force;

[0029] Further, using the principle of minimum potential energy, the contact sub-matrix between the circular elements is constructed, which is represented by the following formula: , where is the normal spring stiffness of the circular element i and the circular element j; is the directional vector matrix between the contact points of the circular element i and the circular element j, where is the x-axis directional vector between the contact points, is the y-axis directional vector between the contact points; is the normal distance of the circular element i and the circular element j;

[0030] The holes, cracks and model outline in contact with the circular element are simulated by line segments, and the contact sub-matrix between the circular element and the line segment is constructed using the principle of minimum potential energy, which is represented by the following formula: , where is the normal spring stiffness of the circular element i and the circular element j or the line segment L; is the directional vector matrix between the contact points of the circular element i and the line segment L, where is the x-axis directional vector between the contact points, is the y-axis directional vector between the contact points; is the normal distance of the contact points of the circular element i and the line segment L;

[0031] The contact sub-matrix between the circular elements and the contact sub-matrix between the circular element and the line segment are added to the total balance equation of the circular element system, and the displacement unknowns in the total balance equation are solved to obtain the displacement increment of the circular element.

[0032] Further, the circular element non-continuous deformation analysis method based on the circular element can also be used to construct and solve equations in the case of three degrees of freedom, four degrees of freedom of the circular element, and the principle is consistent with the above-mentioned two degrees of freedom equation construction and solving method; the two degrees of freedom are X and Y translation, the three degrees of freedom are X, Y translation and rotation, and the four degrees of freedom are X, Y translation, rotation and radius R.

[0033] The step S4 is specifically: for the circle unit obtained in the step S3, continuing to calculate the displacement increment of the circle unit and updating the position of the circle unit according to the displacement increment based on the circle unit non-continuous deformation analysis method until the displacement increment calculated in a single time step is lower than a preset threshold value, the calculation converges, the calculation is stopped, and the finally obtained two-dimensional circle unit model is output as the final result.

[0034] The application discloses a two-dimensional circle unit model generation method for a complex-morphology material containing holes and cracks. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 The figure is a flowchart of the method;

[0036] Figure 2 The figure is a two-dimensional circle unit model generated by using the method in actual application;

[0037] Figure 3 The figure is a two-dimensional complex-morphology material model geometry contour graph drawn in the embodiment of the application;

[0038] Figure 4 The figure is an initial two-dimensional circle unit model graph generated in the embodiment of the application;

[0039] Figure 5 The figure is a two-dimensional circle unit model graph after the circle unit is processed based on the circle unit DDA method in the embodiment of the application. DETAILED DESCRIPTION

[0040] The application provides a two-dimensional circle unit model generation method for a complex-morphology material containing holes and cracks. Figure 1 As shown in the figure, the method comprises the following steps:

[0041] S1. Drawing a two-dimensional complex-morphology material model based on Boolean operation;

[0042] In the step S1, the preset two-dimensional complex-morphology material is discretized into a basic geometry graph, and then a two-dimensional complex-morphology material model is obtained through Boolean operation; the preset two-dimensional complex-morphology material is a complex-morphology material containing holes and cracks.

[0043] The step S1 specifically comprises: abstracting the preset two-dimensional complex topography material into a model outer contour, a hole and a crack; discretizing the model outer contour and the hole into polygons, and drawing the outer contour and the hole of the model through polygon end point coordinates; discretizing the crack into a plurality of line segments, and drawing the plurality of line segments into a plurality of line frames according to the width of the crack; and finally obtaining the two-dimensional complex topography material model through Boolean operation.

[0044] S2. Setting a circle unit parameter, generating an initial circle unit in the two-dimensional complex topography material model, and obtaining an initial two-dimensional circle unit model;

[0045] The step S2 comprises the following steps:

[0046] Setting a circle unit parameter;

[0047] Calculating the area of the two-dimensional complex topography material model;

[0048] Generating a group of circle unit radii according to the area of the two-dimensional complex topography material model and the circle unit parameter;

[0049] Taking points in the model as initial center positions of the circle units, generating the circle units at the initial center positions of the circle units with the group of circle unit radii obtained, and obtaining a group of circle units;

[0050] Continuously reducing the circle unit radii of the group of circle units in equal proportions until all the circle units are not embedded with each other, the circle units are not embedded with the cracks and the hole, and the circle units are not embedded with the model boundary, and finally obtaining a circle unit set and the two-dimensional complex topography material model as an initial two-dimensional circle unit model.

[0051] The step S2 specifically comprises:

[0052] Setting a circle unit density, a circle unit radius distribution form and a circle unit radius range;

[0053] Calculating the area of the two-dimensional complex topography material model;

[0054] According to the area of the two-dimensional complex topography material model and the circle unit density, obtaining a total circle unit area, and continuously generating a group of circle unit radii until the sum of the circle unit areas calculated based on the group of circle unit radii reaches the total circle unit area;

[0055] Uniformly scattering points in the model as initial center positions of the circle units, and then generating the circle units at the initial center positions of the circle units with the group of circle unit radii obtained, and obtaining a group of circle units;

[0056] Continuously reducing the circle unit radii of the group of circle units in equal proportions until all the circle units are not embedded with each other, the circle units are not embedded with the cracks and the hole, and the circle units are not embedded with the model boundary, and finally obtaining a circle unit set and the two-dimensional complex topography material model as an initial two-dimensional circle unit model.

[0057] The circular unit parameters include circular unit density, circular unit radius distribution form, and circular unit radius range; the circular unit density is the ratio of the total area of ​​all circular units in the model to the model area; the circular unit radius distribution forms include equal diameter distribution, uniform distribution, normal distribution, power law distribution, and custom circular unit gradation; specific requirements for determining the circular unit radius range are: when the circular unit radius distribution form is equal diameter distribution, a single circular unit radius value is required to determine the circular unit radius range; when the circular unit radius distribution form is uniform distribution, determining the circular unit radius range requires determining the maximum and minimum radius of the circular unit; when the circular unit radius distribution form is normal distribution, determining the circular unit radius range requires determining the circular unit radius mean, standard deviation, maximum and minimum radius; when the circular unit radius distribution form is power law distribution, determining the circular unit radius range requires determining the power exponent, the maximum and minimum radius of the circular unit; when the circular unit radius distribution form is custom circular unit gradation, determining the circular unit radius range requires determining the radius and proportion of each circular unit.

[0058] S3. Based on the circular element discontinuous deformation analysis method, the circular element displacement increment is calculated by enlarging the circular element, the circular element position is updated, and the circular element enlargement and circular element position adjustment operations are repeated until the radius of all circular elements reaches the preset radius range;

[0059] Step S3 is specifically as follows:

[0060] Continue to proportionally enlarge the circular elements in the initial two-dimensional circular element model obtained in step S2 until the radius of all circular elements reaches the circular element radius range set in step S2; during the enlargement process, when any circular elements or the circular elements and the model contour lines overlap, the displacement increment of the circular elements is calculated based on the circular element discontinuous deformation analysis method and the circular element position is updated before the next proportional enlargement.

[0061] The calculation of the displacement increment of the circular element based on the circular element discontinuous deformation analysis method specifically includes the following steps:

[0062] First, construct the total equilibrium equation for the circular unit system with enlarged radius, and use the following formula to express it: Among them, when hour, is the interaction stiffness submatrix between circular element i and circular element j, and the interaction stiffness submatrix is matrix; is the radius correlation matrix of circular unit i, and the radius correlation matrix is matrix; is the unknown quantum matrix of the displacement of circular unit i, denoted as ,in For circular unit ix directional displacement, is the generalized force vector of the circular element i, denoted as y directional displacement; is the generalized force vector of the circular element i, denoted as wherein is the directional force of the circular element i in x directional force, is the directional force of the circular element i in y directional force;

[0063] Further, using the principle of minimum potential energy, the contact sub-matrix between the circular elements and the circular elements is constructed, and is expressed by the following formula: wherein, is the normal spring stiffness of the circular element i and the circular element j; is the directional vector matrix between the contact points of the circular element i and the circular element j, wherein is the x-axis directional vector between the contact points, is the y-axis directional vector between the contact points; is the normal distance of the circular element i and the circular element j;

[0064] The holes, cracks and the line segments of the outer contour of the model in contact with the circular elements are simulated, and the contact sub-matrix between the circular elements and the line segments is constructed using the principle of minimum potential energy, and is expressed by the following formula: wherein, is the normal spring stiffness of the circular element i and the circular element j or the line segment L; is the directional vector matrix between the contact points of the circular element i and the line segment L, wherein is the x-axis directional vector between the contact points, is the y-axis directional vector between the contact points; is the normal distance of the contact points of the circular element i and the line segment L;

[0065] The contact sub-matrix between the circular elements and the circular elements and the contact sub-matrix between the circular elements and the line segments are added to the total balance equation of the circular element system, and the displacement unknowns in the total balance equation are solved to obtain the displacement increments of the circular elements.

[0066] Further, the displacement increments of the circular elements are calculated based on the circular element non-continuous deformation analysis method, and the equations are constructed and solved based on the three degrees of freedom, four degrees of freedom of the circular element, and the principle is consistent with the equation construction and solving method of the above two degrees of freedom; the two degrees of freedom are X and Y translation, the three degrees of freedom are X, Y translation and rotation, and the four degrees of freedom are X, Y translation, rotation and radius R.

[0067] S4. Based on the circular element non-continuous deformation analysis method, the displacement increment of the circular element is continuously calculated and the position of the circular element is updated until the displacement increment calculated in a single time step is lower than a preset threshold value, and a final two-dimensional circular element model is obtained.

[0068] Step S4 is specifically: for the circular element obtained in step S3, the displacement increment of the circular element is continuously calculated and the position of the circular element is updated according to the displacement increment based on the circular element non-continuous deformation analysis method until the displacement increment calculated in a single time step is lower than a preset threshold value, the calculation converges, the calculation is stopped, and the last obtained two-dimensional circular element model is output as the final result.

[0069] Figure 2 A two-dimensional circular element model obtained by using the method of the present application in actual application is shown in the figure.

[0070] The method of the present application is further described below in combination with an embodiment:

[0071] The node coordinates of the polygon are input, the outer contour and the internal hole are created, the node coordinates of the polyline are input, the fissure is created, the thickness is set to 0.15 m, and then the model geometric contour is drawn through geometric processing, as shown in the figure. Figure 3

[0072] The circular element density is determined to be 1, that is, the total area of the final circular element is equal to the area of the model, the circular element radius distribution form is uniform distribution, the circular element radius range is 0.1 m~0.2 m, and finally 484048 initial circular elements are generated in the model, with a radius range of 0.0512 m~0.1024 m, as shown in the figure. Figure 4

[0073] The radius of the initial circular element is enlarged, at this time the circular element overlaps with the circular element and the model geometric contour, the position of the circular element is calculated based on the circular element DDA, and the circular element is moved to eliminate the overlap. The above process is repeated until the circular element radius reaches 0.1 m~0.2 m. Then, based on the circular element DDA method, the displacement increment of the circular element is calculated, and the position of the circular element is updated. When the displacement increment of the circular element calculated in a single time step is lower than a preset displacement increment, the calculation converges, the calculation is stopped, and the final circular element model is output, as shown in the figure. Figure 5

[0074] Although the present application has been disclosed with the above preferred embodiments, it is not intended to limit the present application. Any person skilled in the art can make many possible changes and modifications to the technical solutions of the present application or modify equivalent embodiments with equivalent changes without departing from the scope of the technical solutions of the present application, using the technical contents disclosed above. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application shall fall within the scope of protection of the technical solutions of the present application.​​​

Claims

1. A method for generating a two-dimensional circular unit model of a material with complex morphology containing holes and cracks, characterized in that: The following steps are included; S1. Render a 2D material model with complex morphology including pores and cracks based on Boolean operations. S2. Set the circular element parameters to generate an initial circular element in the two-dimensional complex morphology material model to obtain an initial two-dimensional circular element model; S3. Based on the circular element discontinuous deformation analysis method, the circular element is enlarged to calculate the unique circular element increment, the circular element position is updated, and the circular element enlargement and circular element position adjustment operations are repeated until the radius of all circular elements reaches the preset radius range; S4. Based on the circular element discontinuous deformation analysis method, continuously calculate the unique circular element increment and update the circular element position until the calculated displacement increment within a single time step is lower than the preset threshold, thereby obtaining the final two-dimensional circular element model; The calculation of the displacement increment of the circular element based on the circular element discontinuous deformation analysis method specifically includes the following steps: First, construct the total equilibrium equation for the circular unit system with enlarged radius, and use the following formula to express it: Among them, when hour, is the interaction stiffness submatrix between circular element i and circular element j, and the interaction stiffness submatrix is matrix; is the radius correlation matrix of circular unit i, and the radius correlation matrix is matrix; is the unknown quantum matrix of the displacement of circular unit i, denoted as ,in is the displacement of circular element i in the x direction, is the displacement of circular element i in the y direction; is the generalized force matrix of circular unit i, denoted as ,in is the force of circular element i in the x direction, is the force of circular element i in the y direction; Then, using the principle of minimum potential energy, the contact submatrix between the circular units is constructed and expressed using the following formula: in, is the normal spring stiffness of circular element i and circular element j; is the direction vector matrix between the contact points of circular element i and circular element j, where is the x-axis direction vector between the contact points, is the y-axis direction vector between the contact points; is the normal distance between circular element i and circular element j; The holes, cracks, and outer contours of the model that are in contact with the circular element are simulated with line segments. The contact submatrix between the circular element and the line segment is constructed using the principle of minimum potential energy, and is expressed using the following formula: in, is the normal spring stiffness of circular element i and circular element j or line segment L; is the direction vector matrix between the circle element i and the contact point of the line segment L, where is the x-axis direction vector between the contact points, is the y-axis direction vector between the contact points; is the normal distance between the contact point of the circular element i and the line segment L; The obtained contact submatrix between circular elements and the contact submatrix between circular elements and line segments are added to the total equilibrium equation of the circular element system, and the unknown displacement in the total equilibrium equation is solved as the displacement increment of the circular element.

2. The method for generating a two-dimensional circular unit model of a material with complex morphology containing holes and cracks according to claim 1, characterized in that: In step S1, a preset two-dimensional complex morphology material is discretized into basic geometric figures and then a two-dimensional complex morphology material model is obtained through Boolean operations; the preset two-dimensional complex morphology material is a complex morphology material containing pores and cracks.

3. The method for generating a two-dimensional circular unit model of a material with complex morphology containing holes and cracks according to claim 2, characterized in that: Step S1 is specifically as follows: abstracting the preset two-dimensional complex morphology material into the model's outer contour, holes, and cracks; discretizing the model's outer contour and holes into polygons, and drawing the model's outer contour and holes using the polygon endpoint coordinates; discretizing the cracks into polylines, and drawing the polylines into polyline frames based on the width of the cracks; and finally obtaining the two-dimensional complex morphology material model through Boolean operations.

4. The method for generating a two-dimensional circular unit model of a material with complex morphology containing holes and cracks according to claim 1, characterized in that: Step S2 includes the following steps: Set the circle unit parameters; Calculate the area of ​​2D complex morphology material models; Generate a set of circular element radii based on the area of ​​the two-dimensional complex morphology material model and the circular element parameters; A point is taken in the model as the initial center position of the circular unit, and a circular unit is generated at the initial center position of the circular unit using a set of circular unit radii to obtain a set of circular units; The circular unit radius of a group of circular units is continuously reduced proportionally until all circular units are not embedded in each other, and there is no embedding between the circular units and cracks, holes, and model boundaries. The final circular unit set and the two-dimensional complex morphology material model are used as the initial two-dimensional circular unit model.

5. The method for generating a two-dimensional circular unit model of a material with complex morphology containing holes and cracks according to claim 4, characterized in that: Step S2 is specifically as follows: Set the circle unit density, circle unit radius distribution form, and circle unit radius range; Calculate the area of ​​2D complex morphology material models; According to the area of ​​the two-dimensional complex morphology material model and the density of the circular unit, a total area of ​​the circular unit is obtained, and a set of circular unit radii is continuously generated until the sum of the circular unit areas calculated based on the set of circular unit radii reaches the total area of ​​the circular unit; Evenly scatter points in the model as the initial center positions of the circular units, and then generate circular units at the initial center positions of the circular units using the obtained set of circular unit radii to obtain a set of circular units; The circular unit radius of a group of circular units is continuously reduced proportionally until all circular units are not embedded in each other, there is no embedding between the circular units and the cracks, and there is no embedding between the circular units and the model boundary. The final circular unit set and the two-dimensional complex morphology material model are used as the initial two-dimensional circular unit model.

6. The method for generating a two-dimensional circular unit model of a material with complex morphology containing holes and cracks according to claim 5, characterized in that: The circular unit parameters include circular unit density, circular unit radius distribution form, and circular unit radius range; the circular unit density is the ratio of the total area of ​​all circular units in the model to the model area; the circular unit radius distribution forms include equal diameter distribution, uniform distribution, normal distribution, power law distribution, and custom circular unit gradation; specific requirements for determining the circular unit radius range are: when the circular unit radius distribution form is equal diameter distribution, a single circular unit radius value is required to determine the circular unit radius range; when the circular unit radius distribution form is uniform distribution, determining the circular unit radius range requires determining the maximum and minimum radius of the circular unit; when the circular unit radius distribution form is normal distribution, determining the circular unit radius range requires determining the circular unit radius mean, standard deviation, maximum and minimum radius; when the circular unit radius distribution form is power law distribution, determining the circular unit radius range requires determining the power exponent, the maximum and minimum radius of the circular unit; when the circular unit radius distribution form is custom circular unit gradation, determining the circular unit radius range requires determining the radius and proportion of each circular unit.

7. The method for generating a two-dimensional circular unit model of a material with complex morphology containing holes and cracks according to claim 1, characterized in that: Step S3 is specifically as follows: Continue to proportionally enlarge the circular elements in the initial two-dimensional circular element model obtained in step S2 until the radius of all circular elements reaches the circular element radius range set in step S2; during the enlargement process, when any circular elements or the circular elements and the model contour lines overlap, the displacement increment of the circular elements is calculated based on the circular element discontinuous deformation analysis method and the circular element position is updated before the next proportional enlargement.

8. The method for generating a two-dimensional circular unit model of a material with complex morphology containing holes and cracks according to claim 7, characterized in that: The discontinuous deformation analysis method based on the circular element calculates the displacement increment of the circular element and can also construct equations for solution based on the three degrees of freedom and four degrees of freedom of the circular element. The principle is consistent with the equation construction and solution method based on two degrees of freedom; the two degrees of freedom are X and Y translation, the three degrees of freedom are X and Y translation and rotation, and the four degrees of freedom are X and Y translation, rotation, and radius R.

9. The method for generating a two-dimensional circular unit model of a material with complex morphology containing holes and cracks according to claim 1, characterized in that: Step S4 is specifically as follows: for the circular element obtained in step S3, continue to calculate the displacement increment of the circular element based on the circular element discontinuous deformation analysis method and update the circular element position according to the displacement increment until the displacement increment calculated in a single time step is lower than the preset threshold, the calculation converges, stop the calculation, and output the final two-dimensional circular element model as the final result.

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