A method and system for generating a microscopic model of a concrete beam with precast cracks

Abstract

This invention discloses a method and system for generating a microscopic model of a concrete beam containing precast cracks, applicable to the field of concrete microscopic finite element model construction technology. The main steps include: determining the specimen size, precast crack size, aggregate volume fraction, gradation curve, interface transition zone thickness, and mesh accuracy based on the required concrete specimen shape and microscopic component characteristics; arranging the discrete elements of the specimen cross-section into a mapping mesh plane based on the specimen size and mesh accuracy; randomly generating aggregate shapes for each gradation level based on the gradation curve, and placing them onto the mapping mesh plane based on boundary exceedance, crack intrusion, and aggregate intrusion criteria; terminating aggregate generation and placement based on whether the volume fractions of each gradation level and the aggregate volume fraction are satisfied, thus obtaining a concrete microscopic model in the form of a mesh mapping. This invention optimizes the aggregate generation process, adjusting its concavity and convexity characteristics through angle and radius transformation coefficients, making the aggregate shape closer to the actual situation.

Description

Technical Field

[0001] This invention relates to the field of concrete micro-finite element model construction technology, and more specifically to a method and system for generating a micro-model of a concrete beam containing precast cracks. Background Technology

[0002] Concrete, as one of the most widely used composite building materials, has a significant impact on the service performance and lifespan of building structures due to its physical and mechanical properties, especially its fracture performance. Three-point or four-point bending beam tests are the most common method for evaluating the fracture performance of concrete, typically requiring the pre-introduction of cracks into the specimen to determine parameters such as crack initiation toughness. Researchers usually employ both laboratory experiments and numerical simulations to analyze the influence of concrete microstructure characteristics on its fracture performance. However, considering the requirements for specimen size, preparation environment, and loading conditions, conducting experiments often presents certain difficulties and limitations; therefore, the importance of numerical simulation research is increasingly evident, and constructing a reasonable and accurate microstructure model of concrete with pre-introduced cracks is crucial for effectively conducting concrete fracture performance simulation experiments.

[0003] At a microscale, concrete can be viewed as a composite material composed of aggregates, mortar, interfacial transition zones, and initial microcracks. The shape, volume fraction, maximum particle size, and gradation information of the aggregates significantly influence the fracture properties of concrete. Considering the uncertainty of the concrete aggregates themselves and their placement, the construction of a concrete microstructure model can be simplified to a process of random aggregate generation and placement, i.e., using a computer to generate random combinations of materials with the same statistical significance as concrete. Most studies have used methods such as simplifying aggregates into more ideal shapes like spheres or ellipsoids to establish characterization models of the concrete microstructure. However, many studies have shown that simplifying the shape of aggregates leads to distortion of simulation results, and random polyhedral aggregates can better describe the microstructural characteristics and macroscopic mechanical properties of concrete materials compared to spherical or ellipsoidal aggregates. Furthermore, many existing microstructure model construction algorithms perform complex geometric calculations for aggregate generation and intrusion judgment, resulting in low aggregate filling rates and low computational efficiency.

[0004] Therefore, proposing a method and system for generating a microscopic model of a concrete beam containing precast cracks to solve the difficulties existing in the prior art is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention provides a method and system for generating a microscopic model of a concrete beam containing precast cracks, which can simultaneously generate a mesh mapping and a geometrically partitioned finite element model of a concrete beam containing precast cracks, so as to meet different needs of numerical simulation of three-point or four-point bending tests of concrete beams.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A method for generating a microscopic model of a concrete beam containing precast cracks includes the following steps:

[0008] S1. Based on the shape and microstructure characteristics of the required concrete specimens, determine the required dimensions L×W, the dimensions l×w of the precast cracks, the number of aggregate volumes Va, the gradation curve, the thickness t of the interface transition zone, and the grid precision a.

[0009] S2. Based on the required size and mesh accuracy of the concrete specimen, the specimen section is discretized into a mapped mesh plane composed of INT(L / a)×INT(W / a) elements, and each element is assigned an initial value of 0. The INT(l / a)×INT(w / a) elements at the precast crack are assigned a value of 2.

[0010] S3. Based on the required gradation curve of the concrete specimen, randomly generate the shape of each grade of aggregate. Through boundary exceedance judgment, crack intrusion judgment and aggregate intrusion judgment, place them in the mapped grid plane and assign a value of 2. Determine the interface position according to the thickness of the transition zone and assign a value of 1.

[0011] S4. By judging whether the volume fraction of each grade and the total volume fraction of aggregate are satisfied, the aggregate generation and placement are terminated. Then, the INT(l / a)×INT(w / a) elements at the precast crack are deleted to obtain the concrete microstructure model in the form of mesh mapping. By recording the aggregate vertex information, the concrete microstructure model in the form of geometric subdivision is generated.

[0012] Optionally, in the above method, the shape of aggregates at each grade is randomly generated in S3, including the following steps:

[0013] 1) Given a random point as the centroid in the mapped grid plane, form a regular n-sided polygon with a random number of sides n on a circle with a certain random particle size as its diameter. The initial diagonal α of each side is given. j (j≤n) is 2π / n;

[0014] 2) Randomize the diagonals of the polygon by randomly selecting two opposite angles α from each side. i ,α j (i,j≤n), use the following formula to randomly transform it to determine the transformed diagonal α′. i ,α′ j :

[0015]

[0016] In the formula: v is the angle transformation coefficient, and r is the distance from each vertex of the polygon after angle randomization to the initial center.j (j≤n) remains the same;

[0017] 3) Use the following formula to evaluate r j Randomize the graph to determine the distance r' from the vertex to the center of the circle after the transformation. j :

[0018] r′ j =r j +rand(-r j ×u,r j ×u)

[0019] In the formula: rand(a,b) means to generate a random number between a and b, and u is the radius transformation coefficient.

[0020] The above method, optionally, includes the following specific content regarding boundary exceedance judgment in S3:

[0021] After the aggregate is generated, the coordinates (x, y) of each vertex are determined based on the diagonal of each vertex and its distance from the initial center. j ,y j Then determine the coordinates (x) j ,y j Check if the aggregate polygon is within the model's boundaries. If all vertices of the aggregate polygon are inside the model, continue the current operation; if any vertices are outside the model, regenerate the aggregate.

[0022] Optionally, the specific details of crack penetration judgment and aggregate penetration judgment in S3 of the above method include:

[0023] When forming aggregates and interface units, if the current value of the assigned unit is found to be equal to 0, the current operation continues; if it is not equal to 0, it is determined that the aggregate has intruded into the aggregate that has already been placed, so the aggregate is discarded, the aggregate is regenerated and placed again.

[0024] Optionally, in the above method, S3 involves placing random aggregates into the mapped grid plane and assigning a value of 2, and determining the interface position based on the transition zone thickness and assigning a value of 1. This includes the following steps:

[0025] 1) Determine the angle β between each side and the x-axis based on the coordinates of each vertex of the aggregate polygon. If |tanβ|<0, define the side as the dominant side of the x-axis; if |tanβ|>0, define the side as the dominant side of the y-axis. When filling the aggregate boundary element, if the vertex of the bisector of the non-dominant axis direction of the element is inside the aggregate, then treat it as an aggregate element and assign it a value of 2.

[0026] 2) Use the flood filling algorithm to assign values ​​to the unassigned units inside the aggregate, that is, assign the value 2 to all the adjacent points of a point until all the points in this area are assigned values;

[0027] 3) Treat the INT(t / a) unit around the aggregate as the interface unit and assign it a value of 1.

[0028] Optionally, in the above method, step S4 involves recording aggregate vertex information to further generate a geometrically partitioned concrete microstructure model. The main content of this step is as follows:

[0029] Record the vertex coordinates of each aggregate polygon and the geometric position of the aggregate polygon within the newly created model plate. Then, perform adaptive re-mesh re-division of the model to generate the concrete micro-geometry model.

[0030] A microstructure model generation system for concrete beams with precast cracks, which applies the above-mentioned method for generating microstructure models of concrete beams with precast cracks, includes a specimen feature determination module, a mapping mesh plane formation module, a graded aggregate shape formation module, and a concrete microstructure model module connected in sequence.

[0031] Specimen characteristic determination module: Based on the shape and microstructure characteristics of the required concrete specimen, determine the required concrete specimen size L×W, precast crack size l×w, aggregate volume fraction Va, gradation curve, interface transition zone thickness t, and mesh accuracy a.

[0032] Mapped Mesh Plane Formation Module: Based on the required size and mesh accuracy of the concrete specimen, the specimen section is discretized into a mapped mesh plane composed of INT(L / a)×INT(W / a) elements, and each element is assigned an initial value of 0. The INT(l / a)×INT(w / a) elements at the precast crack are assigned a value of 2.

[0033] Graded aggregate shape formation module: Based on the required gradation curve of the concrete specimen, randomly generate the shape of each graded aggregate. Through boundary exceedance judgment, crack intrusion judgment and aggregate intrusion judgment, place it in the mapped grid plane and assign a value of 2. Determine the interface position according to the thickness of the transition zone and assign a value of 1.

[0034] Concrete microstructure model: By judging whether the volume fraction of each grade of mix and the total volume fraction of aggregate are satisfied, the generation and placement of aggregate are terminated. Then, INT(l / a)×INT(w / a) elements at the precast crack are deleted, thus obtaining a concrete microstructure model in the form of mesh mapping. By recording the aggregate vertex information, a concrete microstructure model in the form of geometric subdivision is generated.

[0035] As can be seen from the above technical solution, compared with the prior art, the present invention discloses a method and system for generating a microscopic model of a concrete beam containing precast cracks, the beneficial effects of which are:

[0036] (1) The present invention optimizes the generation process of polygonal aggregates. The concave and convex features of the aggregates can be adjusted by the angle transformation coefficient and the radius transformation coefficient, so that the shape of the aggregates is closer to the actual situation.

[0037] (2) The present invention uses the grid assignment test method to judge the intrusion between aggregates, and by pre-setting the precast crack as the aggregate area for intrusion judgment, it avoids the crack being occupied by aggregates. There is no need to perform cumbersome straight line intersection judgment. It has high accuracy and simple calculation, making the algorithm more concise and efficient.

[0038] (3) The present invention can simultaneously generate two concrete beam models with precast cracks based on mesh mapping and geometric subdivision, realizing a four-phase expression of the concrete microstructure, and meeting the different needs of numerical simulation of three-point or four-point bending tests of concrete beams. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0040] Figure 1 A flowchart of a method for generating a microscopic model of a concrete beam with precast cracks, provided by the present invention;

[0041] Figure 2 A flowchart illustrating the overall method for generating a microscopic model of a concrete beam containing precast cracks, provided by this invention.

[0042] Figure 3 A structural block diagram of a system for generating a microscopic model of a concrete beam with precast cracks, provided for this invention;

[0043] Figure 4 This is a diagram illustrating the process of generating random aggregates according to the present invention;

[0044] Figure 5 This is a flowchart illustrating the assignment of values ​​to the four phases of concrete microstructure in this invention.

[0045] Figure 6 This is the aggregate gradation curve of Embodiment 1 of the present invention;

[0046] Figure 7 This is a schematic diagram of the final generated mesh mapping and geometric subdivision model of the concrete beam with precast cracks in Embodiment 1 of the present invention, wherein 7.1 is the mesh mapping model of the concrete beam with precast cracks, and 7.2 is the geometric subdivision model of the concrete beam with precast cracks. Detailed Implementation

[0047] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] See Figure 1 As shown, this invention discloses a method for generating a microscopic model of a concrete beam containing precast cracks, comprising the following steps:

[0049] A method for generating a microscopic model of a concrete beam containing precast cracks includes the following steps:

[0050] S1. Based on the shape and microstructure characteristics of the required concrete specimens, determine the required dimensions L×W, the dimensions l×w of the precast cracks, the number of aggregate volumes Va, the gradation curve, the thickness t of the interface transition zone, and the grid precision a.

[0051] S2. Based on the required size and mesh accuracy of the concrete specimen, the specimen section is discretized into a mapped mesh plane composed of INT(L / a)×INT(W / a) elements, and each element is assigned an initial value of 0. The INT(l / a)×INT(w / a) elements at the precast crack are assigned a value of 2.

[0052] S3. Based on the required gradation curve of the concrete specimen, randomly generate the shape of each grade of aggregate. Through boundary exceedance judgment, crack intrusion judgment and aggregate intrusion judgment, place them in the mapped grid plane and assign a value of 2. Determine the interface position according to the thickness of the transition zone and assign a value of 1.

[0053] S4. By judging whether the volume fraction of each grade and the total volume fraction of aggregate are satisfied, the aggregate generation and placement are terminated. Then, the INT(l / a)×INT(w / a) elements at the precast crack are deleted to obtain the concrete microstructure model in the form of mesh mapping. By recording the aggregate vertex information, the concrete microstructure model in the form of geometric subdivision is generated.

[0054] Furthermore, such as Figure 4 As shown, S3 randomly generates the shapes of aggregates at each grade, including the following steps:

[0055] 1) Given a random point as the centroid in the mapped grid plane, form a regular n-sided polygon with a random number of sides n on a circle with a certain random particle size as its diameter. The initial diagonal α of each side is given. j (j≤n) is 2π / n;

[0056] 2) Randomize the diagonals of the polygon by randomly selecting two opposite angles α from each side. i ,α j (i,j≤n), use the following formula to randomly transform it to determine the transformed diagonal α′. i ,α′ j :

[0057]

[0058] In the formula: v is the angle transformation coefficient, and r is the distance from each vertex of the polygon after angle randomization to the initial center. j (j≤n) remains the same;

[0059] 3) Use the following formula to evaluate r j Randomize the graph to determine the distance r′ from the vertex to the center of the circle after the transformation. j :

[0060] r′ j =r j +rand(-r j ×u,r j ×u)

[0061] In the formula: rand(a,b) means to generate a random number between a and b, and u is the radius transformation coefficient.

[0062] Furthermore, the specific content of the boundary exceedance judgment in S3 includes:

[0063] After the aggregate is generated, the coordinates (x, y) of each vertex are determined based on the diagonal of each vertex and its distance from the initial center. j ,y j Then determine the coordinates (x) j ,y j Check if the aggregate polygon is within the model's boundaries. If all vertices of the aggregate polygon are inside the model, continue the current operation; if any vertices are outside the model, regenerate the aggregate.

[0064] Furthermore, the specific details of crack intrusion and aggregate intrusion judgment in S3 include:

[0065] When forming aggregates and interface units, if the current value of the assigned unit is found to be equal to 0, the current operation continues; if it is not equal to 0, it is determined that the aggregate has intruded into the aggregate that has already been placed, so the aggregate is discarded, the aggregate is regenerated and placed again.

[0066] Furthermore, such as Figure 5 As shown, in S3, random aggregates are placed into the mapped grid plane and assigned a value of 2. The interface position is determined based on the thickness of the transition zone and assigned a value of 1. This includes the following steps:

[0067] 1) Determine the angle β between each side and the x-axis based on the coordinates of each vertex of the aggregate polygon. If |tanβ|<0, define the side as the dominant side of the x-axis; if |tanβ|>0, define the side as the dominant side of the y-axis. When filling the aggregate boundary element, if the vertex of the bisector of the non-dominant axis direction of the element is inside the aggregate, then treat it as an aggregate element and assign it a value of 2.

[0068] 2) Use the flood filling algorithm to assign values ​​to the unassigned units inside the aggregate, that is, assign the value 2 to all the adjacent points of a point until all the points in this area are assigned values;

[0069] 3) Treat the INT(t / a) unit around the aggregate as the interface unit and assign it a value of 1.

[0070] Furthermore, in S4, by recording aggregate vertex information, a geometrically partitioned concrete mesoscopic model is generated, the specific content of which is as follows:

[0071] Record the vertex coordinates of each aggregate polygon and the geometric position of the aggregate polygon within the newly created model plate. Then, perform adaptive re-mesh re-division of the model to generate a concrete micro-geometric subdivision model.

[0072] and Figure 1 Corresponding to the method described above, the present invention also provides a system for generating a microscopic model of a concrete beam containing precast cracks, for use in... Figure 1 The specific implementation of the Chinese method, and its system structure diagram are as follows: Figure 3 As shown, it includes a specimen feature determination module, a mapping mesh plane formation module, a graded aggregate shape formation module, and a concrete microstructure model module connected in sequence;

[0073] Specimen characteristic determination module: Based on the shape and microstructure characteristics of the required concrete specimen, determine the required concrete specimen size L×W, precast crack size l×w, aggregate volume fraction Va, gradation curve, interface transition zone thickness t, and mesh accuracy a.

[0074] Mapped Mesh Plane Formation Module: Based on the required size and mesh accuracy of the concrete specimen, the specimen section is discretized into a mapped mesh plane composed of INT(L / a)×INT(W / a) elements, and each element is assigned an initial value of 0. The INT(l / a)×INT(w / a) elements at the precast crack are assigned a value of 2.

[0075] Graded aggregate shape formation module: Based on the required gradation curve of the concrete specimen, randomly generate the shape of each graded aggregate. Through boundary exceedance judgment, crack intrusion judgment and aggregate intrusion judgment, place it in the mapped grid plane and assign a value of 2. Determine the interface position according to the thickness of the transition zone and assign a value of 1.

[0076] Concrete microstructure model: By judging whether the volume fraction of each grade of mix and the total volume fraction of aggregate are satisfied, the generation and placement of aggregate are terminated. Then, INT(l / a)×INT(w / a) elements at the precast crack are deleted, thus obtaining a concrete microstructure model in the form of mesh mapping. By recording the aggregate vertex information, a concrete microstructure model in the form of geometric subdivision is generated.

[0077] Specifically: Example 1

[0078] S1. Determine the specimen size as 800×200mm 2 The precast crack size is 50×10mm 2 The aggregate volume fraction is 50%, the interface transition zone thickness is 1mm, the grid precision is 1mm, and the aggregate gradation curve is as follows: Figure 4 ;

[0079] S2. Based on the specimen size and mesh accuracy, the specimen section is discretized into a mapped mesh plane consisting of 800×200 elements, and each element is assigned an initial value of 0. The 50×10 elements at the precast crack are assigned a value of 2.

[0080] S3. According to the gradation curve as follows Figure 6 As shown, the shapes of aggregates at each grade are randomly generated. Through boundary exceedance judgment, crack intrusion judgment and aggregate intrusion judgment, they are placed in the mapped grid plane and assigned a value of 2. The interface position is determined according to the thickness of the transition zone and assigned a value of 1.

[0081] S4. By judging whether the volume fraction of each grade of aggregate and the total volume fraction of aggregate are satisfied, the aggregate generation and placement are terminated. Then, the 50×10 elements at the precast cracks are deleted, thus obtaining a concrete mesoscopic model in the form of a mesh mapping. By recording the aggregate vertex information, a concrete mesoscopic model in the form of a geometric partition is generated. The final generated mesh mapping and geometric partition model of the concrete beam with precast cracks in Example 1 is as follows. Figure 7 As shown.

[0082] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0083] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for generating a microscopic model of a concrete beam containing precast cracks, characterized in that, Includes the following steps: S1. Determine the required dimensions of the concrete specimens based on their shape and microstructure characteristics. L×W Dimensions of precast cracks l×w , aggregate volume fraction Va Gradation curve, thickness of interface transition zone t Grid accuracy a ; S2. Based on the required concrete specimen size and mesh accuracy, discretize the specimen cross-section into INT( L / a ) × INT( W / a A mapped mesh plane consisting of ) units is created, and each unit is initialized to 0. The INT(...) value at the prefabricated crack is then... l / a )×INT( w / a ) units are assigned the value 2; S3. Based on the required gradation curve of the concrete specimen, randomly generate the shape of each grade of aggregate. Through boundary exceedance judgment, crack intrusion judgment and aggregate intrusion judgment, project the shape of each grade of aggregate onto the mapped grid plane and assign a value of 2. Determine the interface position based on the thickness of the transition zone and assign a value of 1. S4. Based on whether the volume fractions of each grade and the total volume fraction of aggregates are satisfied, terminate aggregate generation and feeding, and then INT( at the precast crack) l / a )×INT( w / a ) elements are deleted to obtain a concrete microstructure model in the form of a mesh mapping, and a concrete microstructure model in the form of geometric partitioning is generated by recording aggregate vertex information; S3 randomly generates the shapes of aggregates at each grade, including the following steps: 1) Given a random point as the centroid within the mapped grid plane, form a circle with a random number of sides on a circumference with a certain random grain size as the diameter. n of righteousness n polygon, initial opposite angles of each side The value is 2π / n, j≤n; 2) Randomize the diagonals of the polygon by randomly selecting two opposite corners from each side. , The following formula is used to randomly transform it to determine the transformed diagonal. : In the formula: v The angle transformation coefficients represent the distances from each vertex of the polygon after angle randomization to the initial center. Still the same, ; 3) Use the following formula to... Randomize the graph to determine the distance from the vertex to the center of the circle after the transformation. : In the formula: finger take a , b Random numbers between u These are the radius transformation coefficients; The specific content of the boundary exceedance judgment in S3 includes: After the aggregate is generated, the coordinates of each vertex are determined based on the diagonal of each vertex and the distance to the initial center of the circle. Then determine the coordinates If the aggregate polygon is within the model's boundaries, continue the current operation if all vertices are inside the model; otherwise, regenerate the aggregate. The specific content of crack intrusion judgment and aggregate intrusion judgment in S3 includes: When forming aggregates and interface units, if the current value of the assigned unit is found to be equal to 0, the current operation continues; if it is not equal to 0, it is determined that the aggregate has intruded into the aggregate that has already been placed, so the aggregate is discarded, the aggregate is regenerated and placed again.

2. The method for generating a microscopic model of a concrete beam with precast cracks according to claim 1, characterized in that: In S3, random aggregates are placed into the mapped grid plane and assigned a value of 2. The interface position is determined based on the thickness of the transition zone and assigned a value of 1. This includes the following steps: 1) Determine the coordinates of each side and the coordinates of each vertex of the aggregate polygon. Angle between axes ,if Then the edge is defined as The axis is the dominant edge; if Then the edge is defined as Dominant axis edge; When filling aggregate boundary elements, if the vertex of the bisector of the non-dominant axis direction of the element is inside the aggregate, it is treated as an aggregate element and assigned a value of 2. 2) Use the flooding filling algorithm to assign values ​​to the unassigned units inside the aggregate, that is, assign the value 2 to all the adjacent points of a point until all the points in this area are assigned values; 3) INT( around the aggregate) t / a The unit is used as the interface unit and assigned a value of 1.

3. The method for generating a microscopic model of a concrete beam with precast cracks according to claim 1, characterized in that: In S4, by recording the aggregate vertex information, a geometrically partitioned concrete microstructure model is generated. The specific details are as follows: Record the vertex coordinates of each aggregate polygon and the geometric position of the aggregate polygon within the newly created model plate. Then, perform adaptive re-mesh re-division of the model to generate a concrete micro-geometric subdivision model.

4. A system for generating a microscopic model of a concrete beam containing precast cracks, characterized in that... The method for generating a microstructure model of a concrete beam with precast cracks according to any one of claims 1-3 includes a specimen feature determination module, a mapping mesh plane formation module, a graded aggregate shape formation module, and a concrete microstructure model module connected in sequence. Specimen Characterization Module: Based on the shape and microstructure characteristics of the required concrete specimens, determine their dimensions. L×W Dimensions of precast cracks l×w , aggregate volume fraction Va Gradation curve, thickness of interface transition zone t Grid accuracy a ; Mapped Mesh Plane Forming Module: Based on the required concrete specimen size and mesh accuracy, the specimen cross-section is discretized into INT( L / a ) × INT( W / a A mapped mesh plane consisting of ) units is created, and each unit is initialized to 0. The INT(...) value at the prefabricated crack is then... l / a )×INT( w / a ) units are assigned the value 2; Graded aggregate shape formation module: Based on the required gradation curve of the concrete specimen, randomly generate the shape of each graded aggregate. Through boundary exceedance judgment, crack intrusion judgment and aggregate intrusion judgment, place it in the mapped grid plane and assign a value of 2. Determine the interface position according to the thickness of the transition zone and assign a value of 1. Concrete microstructure model module: This module terminates aggregate generation and placement by determining whether the volume fractions of each mix grade and the total aggregate volume fraction are met. Then, it calculates the INT(...) value at the precast cracks. l / a )×INT( w / a The concrete microstructure model is obtained by deleting 100 units and then generating a geometrically partitioned concrete microstructure model by recording aggregate vertex information.

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