Method and system for generating three-dimensional meso-model of fiber reinforced recycled concrete based on boolean operation

Abstract

The application aims to provide a generation method and system of a fiber reinforced recycled concrete three-dimensional mesoscopic model based on Boolean operation, mainly considering the influence of the gradation, shape, replacement rate and old mortar content of recycled coarse aggregate and the influence of the shape, characteristic parameter and unit type of fiber. Meanwhile, the Boolean operation is used to perform collision test on the aggregate and fiber, to quickly generate a fiber reinforced recycled concrete three-dimensional mesoscopic random aggregate model, which can be effectively used to simulate the real damage characteristics of recycled concrete. The method comprises the following steps: step 1, generating a matrix under a given shape; step 2, generating coarse aggregate under a random shape and a given gradation; step 3, generating old mortar on the surface of the coarse aggregate to form recycled coarse aggregate; and step 4, generating fiber under a given shape, characteristic parameter and unit type.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of fiber reinforced concrete meso simulation, and particularly relates to a method and system for generating a three-dimensional meso model of fiber reinforced recycled concrete based on Boolean operation. BACKGROUND

[0002] As a green and recycled resource, recycled concrete is formed by mixing waste concrete with natural aggregate after crushing, cleaning and screening. The meso components of recycled aggregate are more complex than those of ordinary concrete because of the large amount of old mortar attached to the surface of recycled aggregate. A large number of studies have shown that the mechanical properties of recycled concrete are inferior to those of ordinary concrete, but the mechanical properties can still be effectively improved by proper modification (such as adding an appropriate amount of fiber), so that recycled concrete can replace ordinary concrete in engineering applications.

[0003] In order to promote the engineering application of recycled concrete materials, appropriate research methods are needed to reveal the real failure mode and damage mechanism. With the continuous development of computer technology and the continuous maturity of related numerical simulation technology, random aggregate models considering the internal meso structure of aggregate shape, gradation, etc. are used to study the meso failure mechanism of concrete materials. At present, the method of simplifying aggregate into a circle and randomly placing it to generate a circular random aggregate model is relatively mature and common, but the shape and type of coarse aggregate have a certain influence on the calculation results. Especially for recycled coarse aggregate, the influence of the old mortar attached to its surface on the mechanical properties and damage characteristics cannot be ignored. On the other hand, for fibers, the common practice in numerical modeling technology is to simplify the fiber into a straight linear element. This approach is relatively simple and has high calculation speed when testing the collision of fibers in the model. However, in actual situations, other different shaped fibers such as corrugated and end-hook shaped fibers are often used in tests. At this time, if the fiber is still equivalent to a straight shape, it is difficult to be convincing. SUMMARY

[0004] The present application is made to solve the above problems, and aims to provide a method and system for generating a three-dimensional meso model of fiber reinforced recycled concrete based on Boolean operation, mainly considering the influence of the gradation, shape, replacement rate and old mortar content of recycled coarse aggregate and the shape, characteristic parameters and element type of fiber. At the same time, Boolean operation is used to test the collision of aggregate and fiber, and a three-dimensional meso random aggregate model of fiber reinforced recycled concrete is quickly generated, which can be effectively used to simulate the real failure characteristics of recycled concrete.

[0005] In order to achieve the above purpose, the present application adopts the following scheme:

[0006] A method for generating a three-dimensional microstructure model of fiber-reinforced recycled concrete based on Boolean operations includes the following steps:

[0007] Step 1: Generate a matrix of a given shape and then generate a model surrounding the matrix.

[0008] Step 2, Generate coarse aggregate with random shape and given gradation: Randomly add aggregates to the matrix in sequence, and perform subtraction test on the aggregates based on Boolean operation;

[0009] Step 3: Old mortar is generated on the surface of the coarse aggregate to form recycled coarse aggregate;

[0010] Step 4: Generate fibers with given shape, feature parameters and unit type. After determining the fiber shape parameters and unit type, and the given number of fibers, add them into the matrix in sequence, and perform a subtraction test on the fibers based on Boolean operation.

[0011] Furthermore, step 2 includes the following sub-steps:

[0012] Step 2.1, Determine the shape of the coarse aggregate:

[0013] First, a certain number of points are generated as vertices of the aggregate; then these points are connected to form an envelope; next, these lines are used to form surfaces to generate the aggregate shell structure; finally, the shell is filled to form the aggregate solid.

[0014] Step 2.2, determine aggregate gradation:

[0015] Based on the standard Fuller gradation formula, the aggregate gradation in three-dimensional space is determined:

[0016]

[0017] In the formula, D max P(D0) represents the maximum aggregate size; P(D0) represents the volume percentage of aggregate with a size smaller than D0.

[0018] Based on Fuller's formula, the aggregate volume within each particle size range can be calculated:

[0019]

[0020] In the formula, v(D) i D j ) indicates that the particle size is in the range of D i ~D j Volume of coarse aggregate within the range; D max D min These represent the maximum and minimum coarse aggregate particle sizes, respectively; p k This indicates the volume ratio of coarse aggregate to concrete volume;

[0021] Step 2.3: Generate aggregate.

[0022] Furthermore, step 2.3 specifically includes:

[0023] The first step is to randomly generate the coordinates of the aggregate addition location and add the aggregate at that location. The second step is to first evaluate the model outside the matrix; if successful, abandon the addition and return to the first step; if unsuccessful, proceed to the next step. The third step is to perform a subtraction test on the newly added aggregate and the set of all previously added aggregates; if successful, abandon the addition and return to the first step; if unsuccessful, retain the aggregate and add it to the aggregate set for the next subtraction test. Finally, when each particle size range (D...) i ~D j The volume of the aggregate incorporated all reached v(D) i D j When the aggregate is generated, the aggregate production is complete.

[0024] Furthermore, the specific method for generating old mortar on the surface of coarse aggregate in step 3 is as follows:

[0025] Step 3.1. Divide all aggregates into a grid to form an aggregate unit set;

[0026] Step 3.2. Set the recycled coarse aggregate replacement rate to r%, then randomly select r% of the aggregate as recycled coarse aggregate; and set the volume content of the old mortar, expressed as v. oc In the set of recycled coarse aggregate units, v is randomly selected. oc The proportional units are given the material properties of old mortar, while the remaining units are given the material properties of natural aggregate.

[0027] Furthermore, step 4 includes the following sub-steps:

[0028] Step 4.1, Set fiber shape parameters: Determine the fiber shape according to actual needs;

[0029] Step 4.2, Determine the fiber unit type: Select to set the fiber as a 1D linear unit or a 3D solid unit;

[0030] Step 4.3, generating fibers: After determining the fiber shape parameters and single type, and given the number of fibers, they are sequentially incorporated into the matrix.

[0031] Furthermore, the process of incorporating aggregates into the matrix is ​​as follows:

[0032] The first step is to generate random locations within the matrix and incorporate fibers at these locations. The second step is to evaluate the fiber's compatibility with the matrix's external model. If successful, the incorporation is abandoned, and the process returns to the first step. If it fails, the process proceeds to the next step. The third step is to evaluate the fiber and aggregate set. If successful, the incorporation is abandoned, and the process returns to the first step. If it fails, the process proceeds to the next step. The fourth step is to perform a subtraction test on the newly incorporated fiber and the set of all previously incorporated fibers. If successful, the incorporation is abandoned, and the process returns to the first step. If it fails, the fiber is retained and added to the fiber set for the next subtraction test. This process is repeated until a sufficient number of fibers are generated.

[0033] Furthermore, in step 4, fiber models that meet various requirements are generated. In terms of geometry, they include straight, corrugated, and hooked shapes, and the shape parameters can be set arbitrarily. For different fibers, their shape parameters are set separately, including fiber length l and diameter d. For corrugated fibers, the number of corrugations n and corrugation width w1 are also included; for hooked fibers, the hook length l2 and width w2 are also included. In terms of model type, they include 1-dimensional linear units and 3-dimensional solid units.

[0034] On the other hand, the present invention provides a three-dimensional microscopic model generation system for fiber-reinforced recycled concrete based on Boolean operations, comprising:

[0035] The matrix generation section generates a three-dimensional micro-random aggregate model of recycled concrete with corresponding shape and size based on the information of the fiber-reinforced recycled concrete to be simulated.

[0036] Old mortar generation section: By imparting material properties, old mortar is applied to the surface of coarse aggregate;

[0037] The aggregate generation section generates coarse aggregates within each particle size range based on the aggregate gradation of fiber-reinforced recycled concrete.

[0038] The fiber generation section randomly generates fibers in the three-dimensional microscopic model of recycled concrete.

[0039] Furthermore, it also includes:

[0040] The control unit is communicatively connected to the matrix generation unit, aggregate generation unit, old mortar generation unit, and fiber generation unit, and controls their operation.

[0041] The input display unit is communicatively connected to the control unit and is used to allow the user to input operation commands and display the corresponding commands.

[0042] Furthermore, both the aggregate generation section and the fiber generation section perform subtraction tests on aggregates and fibers respectively, based on the concept of Boolean operations.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] 1) This invention mainly utilizes the "subtraction" operation based on Boolean operations, which eliminates a large number of cumbersome geometry-based "collision test" algorithms, thereby unifying the generation of matrices of different shapes, aggregates with arbitrary parameters, and fibers of different shapes and parameters.

[0045] 2) This invention avoids setting up a geometric model. Instead, by assigning material properties to the model units, it generates old mortar on the surface of recycled coarse aggregate based on the specific old mortar content, which is more in line with the real random distribution and can also improve the quality of the model mesh.

[0046] 3) This invention can generate fiber models that meet various needs. In terms of geometry, they include straight, corrugated, and hooked shapes, and the shape parameters can be set arbitrarily. In terms of model type, they include 1-dimensional linear units and 3-dimensional solid units to meet different simulation requirements.

[0047] 4) The present invention has simple operation steps, reasonable design, convenient implementation, good use effect, and low investment cost, and can be well applied to the microscopic numerical simulation of fiber-reinforced recycled concrete. Attached Figure Description

[0048] Figure 1 The flowchart is a method for generating a three-dimensional microscopic model of fiber-reinforced recycled concrete based on Boolean operations, as disclosed in this invention.

[0049] Figure 2 This invention relates to an algorithm for controlling fibers and aggregates within a matrix based on Boolean subtraction operations;

[0050] Figure 3 This is a schematic diagram of the geometric generation of coarse aggregate according to the present invention;

[0051] Figure 4 This invention relates to a schematic diagram of coarse aggregate collision detection based on the Boolean operation "subtraction".

[0052] Figure 5 This is a schematic diagram illustrating the generation of old mortar, as per the present invention.

[0053] Figure 6 This invention relates to schematic diagrams of fibers of different shapes and their parameters.

[0054] Figure 7 This invention relates to schematic diagrams of fibers of different model types;

[0055] Figure 8 This invention relates to a schematic diagram of fiber collision determination based on the Boolean operation "subtraction".

[0056] Figure 9 The three-dimensional mesoscopic random aggregate models of corrugated fiber-reinforced recycled concrete under different matrix shapes in Embodiment 1 of the present invention are shown below: (a) cube; (b) prism.

[0057] Figure 10 The following are three-dimensional mesoscopic random aggregate models of corrugated fiber reinforced recycled concrete under different fiber model types in Embodiment 2 of the present invention, wherein (a) is a 1-dimensional linear element; and (b) is a 3-dimensional solid element.

[0058] Figure 11 This invention relates to Embodiment 4, which describes a 3D solid unit, corrugated fiber reinforced recycled concrete 3D micro-random aggregate model with different old mortar contents; wherein, (a) the old mortar content is 0%; (b) the old mortar content is 12%; and (c) the old mortar content is 24%.

[0059] Figure 12 The three-dimensional micro-random aggregate model of recycled concrete reinforced with fiber-reinforced 3D solid unit under different fiber shapes in Embodiment 3 of the present invention; wherein, (a) is straight; (b) is corrugated; and (c) is hooked. Detailed Implementation

[0060] To facilitate understanding and implementation of the present invention by those skilled in the art, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0061] like Figure 1 As shown, this invention provides a method for generating a three-dimensional microstructure model of fiber-reinforced recycled concrete based on Boolean operations, comprising the following steps:

[0062] Step 1: Generate the base material of the given shape;

[0063] First, the basic shape and dimensions of the 3D model need to be determined. In general modeling methods, collision algorithms are often designed for only a specific geometric shape (i.e., the aggregate and fibers do not exceed the range of the matrix). However, in general, the shapes of the specimens used in experiments often include cubes and cylinders.

[0064] Preferably, the method for generating a three-dimensional microscopic model of fiber-reinforced recycled concrete based on Boolean operations provided by the present invention is based on the idea of ​​Boolean operations (geometric processing operations, including "union", "intersection", and "subtraction". This method focuses on using the "subtraction" algorithm), which unifies models of different shapes and can be set according to actual needs (inputting "cubic" for cubes or "cylinder" for cylinders). After determining the shape of the model, the size parameters of the model are input: length, width, and height.

[0065] Outside the matrix, a sufficiently large model is generated to surround the matrix. The purpose is to perform Boolean operations between this model and the aggregates and fibers. Specifically, for each aggregate or fiber generated, an attempt is made to perform a "shear" operation on the model outside the matrix. If the judgment is successful, it means the aggregate or fiber exceeds the matrix's boundaries, and the generated aggregate or fiber is discarded; if the judgment fails, it is retained, and subsequent judgments continue. Figure 2 As shown.

[0066] Step 2, generating coarse aggregate of random shape and given gradation; includes the following sub-steps:

[0067] Step 2.1, Determine the shape of the coarse aggregate:

[0068] To reflect a more realistic situation, the aggregate shape is set as a random, irregular body. The generation concept is: point—line—surface—volume. First, a certain number of points are generated as the vertices of the aggregate; then these points are connected to form an envelope; next, these lines are used to form surfaces, generating the aggregate shell structure; finally, the shell is filled to form the aggregate solid. For example... Figure 3 As shown.

[0069] Step 2.2, determine aggregate gradation:

[0070] Based on the standard Fuller gradation formula, the aggregate gradation in three-dimensional space is determined:

[0071]

[0072] In the formula, D max P(D0) represents the maximum aggregate size; P(D0) represents the volume percentage of aggregates with a size smaller than D0.

[0073] Based on Fuller's formula, the aggregate volume within each particle size range can be calculated:

[0074]

[0075] In the formula, v(D) i D j) indicates that the particle size is in the range of D i ~D j Volume of coarse aggregate within the range; D max D min These represent the maximum and minimum coarse aggregate particle sizes, respectively; p k This indicates the volume ratio of coarse aggregate to concrete volume.

[0076] Step 2.3, Generate aggregate:

[0077] like Figure 2 As shown, this invention provides a method for generating a three-dimensional microscopic model of fiber-reinforced recycled concrete based on Boolean operations. Aggregates are randomly added sequentially to the matrix, and a "subtraction test" is performed on the aggregates based on Boolean operations. The method mainly includes three parts: First, randomly generating the coordinates of the aggregate addition location and adding aggregates at these locations; second, as described in step 1, first judging the aggregates against the model outside the matrix. If successful, the addition is abandoned, and the process returns to step 1; if it fails, the process proceeds to the next step. Third, a "subtraction test" is performed on the newly added aggregates and the set of all previously added aggregates. If the judgment is successful, the addition is abandoned, and the process returns to step 1; if it fails, the aggregates are retained and added to the aggregate set for the next "subtraction test." Figure 4 As shown.

[0078] Ultimately, when within each particle size range (D) i ~D j The volume of the aggregate incorporated all reached v(D) i D j When the aggregate is generated, the aggregate production is complete.

[0079] Step 3: Old mortar is generated on the surface of the coarse aggregate to form recycled coarse aggregate;

[0080] The surface of recycled coarse aggregate is randomly covered with a large amount of old mortar. The current common modeling method is to set a geometrically uniform layer around the aggregate, which is seriously inconsistent with the actual random distribution of old mortar (which is randomly distributed inside and outside the recycled coarse aggregate). Moreover, this approach is often only suitable for spherical aggregates, and it is very difficult for irregular solid aggregates.

[0081] Preferably, the method for generating a three-dimensional mesoscopic model of fiber-reinforced recycled concrete based on Boolean operations provided by this invention does not start from the geometric level, but directly achieves the "establishment" of old mortar by assigning material properties to the model elements. Specifically: First, mesh all aggregates to form an aggregate element set. Second, set the recycled coarse aggregate replacement rate to r%, then randomly select r% of the aggregates as recycled coarse aggregates; and set the volume content of old mortar, expressed as v. oc In the set of recycled coarse aggregate units, v is randomly selected.oc The method assigns material properties of old mortar to proportional elements and material properties of natural aggregate to the remaining elements. This method perfectly realizes the random distribution of old mortar within and around the recycled coarse aggregate, and because it does not change the geometry of the aggregate, it improves the quality of the generated mesh, facilitating subsequent finite element calculations. Figure 5 As shown.

[0082] Step 4: Generate fibers with the given shape, feature parameters, and unit type; including the following sub-steps:

[0083] Step 4.1, set fiber shape parameters:

[0084] Preferably, the method for generating a three-dimensional microscopic model of fiber-reinforced recycled concrete based on Boolean operations provided by this invention involves first determining the shape of the fiber according to actual needs when incorporating fibers into the matrix. The fiber can be selected as a straight "line," a corrugated "corrugated," or a hooked "hook." For different fibers, their shape parameters are set separately, including fiber length l and diameter d. For corrugated fibers, this also includes the number of corrugations n and the corrugation width w1; for hooked fibers, this includes the hook length l2 and the hook width w2. Figure 6 As shown.

[0085] Step 4.2, determine the fiber unit type:

[0086] Traditional methods mostly equate fibers to 1-dimensional linear units.

[0087] Preferably, the present invention provides a method for generating a three-dimensional microscopic model of fiber-reinforced recycled concrete based on Boolean operations. To improve the flexibility of model design, the fibers can be set as 1-dimensional linear elements (without fiber diameter parameters) or 3-dimensional solid elements. For example... Figure 7 As shown.

[0088] Step 4.3, generating fibers:

[0089] After determining the fiber shape parameters and single type, and specifying the number of fibers, they are sequentially incorporated into the matrix.

[0090] Preferably, the present invention provides a method for generating a three-dimensional microscopic model of fiber-reinforced recycled concrete based on Boolean operations. This method uses a Boolean algorithm to perform a "subtraction test" on the fibers. Compared to aggregates, the operation on fibers is more complex, specifically including the following steps: First, generate random locations within the matrix and incorporate fibers at these locations; Second, evaluate the fiber and matrix external model. If successful, abandon the incorporation and return to the first step; if unsuccessful, proceed to the next step. Third, evaluate the fiber and aggregate set. If successful, abandon the incorporation and return to the first step; if unsuccessful, proceed to the next step. Fourth, perform a "subtraction test" on the newly incorporated fiber and the set of all previously incorporated fibers. If successful, abandon the incorporation and return to the first step; if unsuccessful, retain the fiber and add it to the fiber set for the next "subtraction test." Repeat the above operations until a sufficient number of fibers are generated. Figure 8 As shown.

[0091] Furthermore, the present invention also provides a system for generating a three-dimensional microscopic model of fiber-reinforced recycled concrete based on Boolean operations, which can automatically implement the above method, including:

[0092] The matrix generation section generates a three-dimensional micro-random aggregate model of recycled concrete with corresponding shape and size based on the information of the fiber-reinforced recycled concrete to be simulated.

[0093] The aggregate generation section generates coarse aggregates within each particle size range based on the aggregate gradation of fiber-reinforced recycled concrete.

[0094] The following steps 2.1 to 2.3 are used to randomly generate coarse aggregates in the three-dimensional microstructure model of recycled concrete;

[0095] Step 2.1, Determine the shape of the coarse aggregate:

[0096] First, a certain number of points are generated as vertices of the aggregate; then these points are connected to form an envelope; next, these lines are used to form surfaces to generate the aggregate shell structure; finally, the shell is filled to form the aggregate solid.

[0097] Step 2.2, determine aggregate gradation:

[0098] Based on the standard Fuller gradation formula, the aggregate gradation in three-dimensional space is determined:

[0099]

[0100] In the formula, D max P(D0) represents the maximum aggregate size; P(D0) represents the volume percentage of aggregates with a size smaller than D0.

[0101] Based on Fuller's formula, the aggregate volume within each particle size range can be calculated:

[0102]

[0103] In the formula, v(D) i D j ) indicates that the particle size is in the range of D i ~D j Volume of coarse aggregate within the range; D max D min These represent the maximum and minimum coarse aggregate particle sizes, respectively; p k This indicates the volume ratio of coarse aggregate to concrete volume.

[0104] Step 2.3, Generate aggregate:

[0105] Aggregates are randomly added sequentially to the matrix, and a "subtraction test" is performed on the aggregates based on Boolean operations. This process mainly consists of three parts: First, the coordinates of the aggregate addition location are randomly generated, and the aggregate is added at that location. Second, as described in step 1, the model outside the matrix is ​​first evaluated. If successful, the addition is abandoned, and the process returns to step 1; if it fails, the process proceeds to the next step. Third, a "subtraction test" is performed on the newly added aggregate and the set of all previously added aggregates. If successful, the addition is abandoned, and the process returns to step 1; if it fails, the aggregate is retained and added to the aggregate set for the next "subtraction test."

[0106] The old mortar generation section applies old mortar to the surface of coarse aggregates by assigning material properties. The first step involves dividing all aggregates into a grid, forming aggregate unit sets. The second step sets the recycled coarse aggregate replacement rate to r%, then randomly selects r% of the aggregates as recycled coarse aggregates; and sets the volume content of the old mortar, denoted as v. oc In the aggregate unit set, v is randomly selected. oc The proportional units are given the material properties of old mortar, while the remaining units are given the material properties of natural aggregate.

[0107] The fiber generation section employs the following steps 4.1 to 4.3 to randomly generate fibers in the three-dimensional microscopic model of recycled concrete;

[0108] Step 4.1, set fiber shape parameters:

[0109] When incorporating fibers into a matrix, the shape of the fibers is first determined based on actual needs. Options include straight ("line"), corrugated ("corrugated"), and hooked ("hook"). For different fibers, shape parameters are set separately, including fiber length *l* and diameter *d*. For corrugated fibers, this also includes the number of corrugations *n* and corrugation width *w1*; for hooked fibers, this includes hook length *l2* and hook width *w2*.

[0110] Step 4.2, determine the fiber unit type:

[0111] Choose to set the fiber as a 1D linear unit (in which case there is no fiber diameter parameter) or a 3D solid unit.

[0112] Step 4.3, generating fibers:

[0113] After determining the fiber shape parameters and type, and given the number of fibers, they are sequentially incorporated into the matrix. Similarly, a "subtraction test" is performed on the fibers using a Boolean algorithm. This includes the following steps: First, a random location is generated within the matrix, and the fiber is incorporated at this location. Second, the fiber is compared to the matrix outer model; if successful, the incorporation is abandoned, and the process returns to the first step; otherwise, the process continues. Third, the fiber is compared to the aggregate set; if successful, the incorporation is abandoned, and the process returns to the first step; otherwise, the process continues. Fourth, a "subtraction test" is performed between the newly incorporated fiber and the set of all previously incorporated fibers; if successful, the incorporation is abandoned, and the process returns to the first step; otherwise, the fiber is retained and added to the fiber set for the next "subtraction test." This process is repeated until a sufficient number of fibers are generated.

[0114] The control unit is connected in communication with the matrix generation unit, aggregate generation unit, old mortar generation unit, and fiber generation unit, and controls their operation.

[0115] Preferably, the system for generating a three-dimensional microscopic model of fiber-reinforced recycled concrete based on Boolean operations provided by the present invention may further include: an input display unit, communicatively connected to the control unit, for allowing users to input operation commands and displaying them accordingly. Through the graphical user interface of the input display unit, users can intuitively and quickly operate the generated and viewed models; the model parameters are highly adjustable and have a wide range of applications.

[0116] <Example 1>

[0117] The purpose of this first embodiment is to generate a 3D mesoscopic random aggregate model of fiber-reinforced recycled concrete with different matrix shapes. The matrix dimensions (length×width×height) are 75mm×75mm×75mm; the coarse aggregate particle size range is 10-20mm, and the volumetric admixture is 0.4; the fiber is a 3D solid corrugated fiber with 5 corrugations, a corrugation width of 2mm, a fiber length of 16mm, a diameter of 0.2mm, and a quantity of 100. The generation results are shown in [link to example]. Figure 8 .

[0118] <Example 2>

[0119] The purpose of this second embodiment is to generate 3D mesoscopic random aggregate models of corrugated fiber-reinforced recycled concrete under different fiber model types. The fiber model types are set as 1D linear elements and 3D solid elements. The cube matrix dimensions (length×width×height) are 75mm×75mm×75mm; the coarse aggregate particle size range is 10-20mm, and the volumetric admixture is 0.4; the end-hook fibers have an end-hook length and width of 2mm; the fiber length is 16mm, the diameter is 0.2mm, and the quantity is 100. The generation results are shown in [link to example]. Figure 9 .

[0120] <Example 3>

[0121] like Figure 12 The purpose of this third embodiment is to generate a 3D micro-random aggregate model of recycled concrete reinforced with corrugated fibers, consisting of 3D solid elements, under different old mortar contents. The old mortar contents are set to 0%, 12%, and 24%, respectively. The cube matrix dimensions (length × width × height) are 75mm × 75mm × 75mm; the coarse aggregate particle size range is 10–20mm, with a volumetric admixture of 0.4; the fiber length is 16mm, the diameter is 0.2mm, and the quantity is 100. The generation results are shown in [link to example]. Figure 10 .

[0122] <Example 4>

[0123] The purpose of this fourth embodiment is to generate 3D microscopic random aggregate models of recycled concrete reinforced with 3D solid unit fibers under different fiber shapes. The fiber shapes are set as straight, corrugated, and hooked. The cylindrical matrix dimensions (length × width × height) are 75mm × 75mm × 75mm; the coarse aggregate particle size range is 10–20mm, and the volumetric admixture is 0.4; the 3D solid fibers have a length of 16mm, a diameter of 0.2mm, and a quantity of 100. For corrugated fibers, the number of corrugations is 5, and the corrugation width is 2mm; for hooked fibers, the hook length and width are both 2mm. The generated results are shown in [link to example]. Figure 11 .

[0124] <Example 5>

[0125] In this fifth embodiment, a system is provided that can automatically generate a three-dimensional microscopic model of fiber-reinforced recycled concrete based on Boolean operations using the method of the present invention. The system includes a matrix generation unit, an aggregate generation unit, an old mortar generation unit, a fiber generation unit, an input display unit, and a control unit.

[0126] The matrix generation unit performs the steps described in step 1 above, generating a three-dimensional matrix of fiber-reinforced recycled concrete of corresponding size and shape based on the information of the fiber-reinforced recycled concrete to be simulated.

[0127] The aggregate generation section performs the steps described in step 2 above. First, it uses the "point-line-surface-volume" method to generate the aggregate shape. Then, based on the aggregate gradation of the 3D microscopic random aggregate model of fiber-reinforced recycled concrete, it calculates the volume of recycled coarse aggregate within each particle size range. Based on the Boolean operation "subtraction" algorithm, the aggregate is sequentially added into the matrix to control the aggregate to be located inside the matrix and not to collide with each other.

[0128] The old mortar generation section performs the steps described in step 3 above, first dividing the aggregate into grids to form units; setting the old mortar content, and setting different material properties for the units to achieve random distribution of old mortar on the surface of the recycled coarse aggregate;

[0129] The fiber generation section performs the steps described in step 4 above, setting the shape and unit type of the fiber; inputting the number of fibers; and sequentially incorporating fibers into the matrix based on the Boolean subtraction operation algorithm, controlling the fibers to be located inside the matrix and not to collide with the aggregate or with each other.

[0130] The input display unit is used to allow users to input operation commands and displays the corresponding information. For example, the input and output data and processing procedures of each unit are displayed in the form of text, tables, or static or dynamic graphs.

[0131] The control unit is connected in communication with the matrix generation unit, aggregate generation unit, old mortar generation unit, fiber generation unit, and input display unit to control their operation.

[0132] The above embodiments are merely illustrative examples of the technical solutions of the present invention. The method and system for generating three-dimensional microscopic models of fiber-reinforced recycled concrete based on Boolean operations involved in the present invention are not limited to the content described in the above embodiments, but are defined by the scope of the claims. Any modifications, additions, or equivalent substitutions made by those skilled in the art based on these embodiments are within the scope of protection claimed by the claims of the present invention.

Claims

1. A method for generating a three-dimensional microscopic model of fiber-reinforced recycled concrete based on Boolean operations, characterized in that, Includes the following steps: Step 1: Generate a matrix of a given shape and then generate a model surrounding the matrix. Step 2, generating coarse aggregates of random shape and given gradation: Aggregates are randomly added sequentially to the matrix, and a subtraction test is performed on the aggregates based on Boolean operations; this includes the following sub-steps: Step 2.1, Determine the shape of the coarse aggregate: First, a certain number of points are generated as vertices of the aggregate; then these points are connected to form an envelope; next, these lines are used to form surfaces to generate the aggregate shell structure; finally, the shell is filled to form the aggregate solid. Step 2.2, determine aggregate gradation: Based on the standard Fuller gradation formula, the aggregate gradation in three-dimensional space is determined: In the formula, D max Indicates the maximum aggregate particle size; P ( D 0) indicates that the particle size is smaller than D 0% of aggregate volume; Based on Fuller's formula, the aggregate volume within each particle size range can be calculated: In the formula, Indicates particle size at D i ~ D j The volume of coarse aggregate within the specified range; D max , D min These represent the maximum and minimum coarse aggregate particle sizes, respectively. p k This indicates the volume ratio of coarse aggregate to concrete volume; Step 2.3, Generate Aggregate; specifically: First, randomly generate aggregate incorporation location coordinates and incorporate aggregate at these locations; Second, first, judge the model outside the matrix with respect to the aggregate. If successful, abandon this incorporation and return to the first step; if unsuccessful, proceed to the next step; Third, perform a subtraction test on the newly incorporated aggregate and the set of all already incorporated aggregates. If successful, abandon this incorporation and return to the first step; if unsuccessful, retain the aggregate and add it to the aggregate set for the next subtraction test; Finally, when each particle size range ( D i ~ D j The volume of the added aggregates all reached Aggregate generation is completed at that time; Step 3: Old mortar is generated on the surface of the coarse aggregate to form recycled coarse aggregate; Step 4: Generate fibers with given shape, feature parameters and unit type. After determining the fiber shape parameters and unit type, and the given number of fibers, add them into the matrix in sequence, and perform a subtraction test on the fibers based on Boolean operation.

2. The method for generating a three-dimensional microstructure model of fiber-reinforced recycled concrete based on Boolean operations according to claim 1, characterized in that: The specific method for generating old mortar on the surface of coarse aggregate in step 3 is as follows: Step 3.

1. Divide all aggregates into a grid to form an aggregate unit set; Step 3.

2. Set the recycled coarse aggregate replacement rate. r %, then select randomly. r % of aggregate is used as recycled coarse aggregate; and the volume content of old mortar is set, expressed as... v oc Randomly select from the set of recycled coarse aggregate units v oc The proportional units are given the material properties of old mortar, while the remaining units are given the material properties of natural aggregate.

3. The method for generating a three-dimensional microstructure model of fiber-reinforced recycled concrete based on Boolean operations according to claim 1, characterized in that: Step 4 includes the following sub-steps: Step 4.1, Set fiber shape parameters: Determine the fiber shape according to actual needs; Step 4.2, Determine the fiber unit type: Select to set the fiber as a 1D linear unit or a 3D solid unit; Step 4.3, generating fibers: After determining the fiber shape parameters and single type, and given the number of fibers, they are sequentially incorporated into the matrix.

4. The method for generating a three-dimensional microstructure model of fiber-reinforced recycled concrete based on Boolean operations according to claim 3, characterized in that: The process of incorporating aggregates into the matrix is ​​as follows: The first step is to generate random locations within the matrix and incorporate fibers at these locations. The second step is to evaluate the relationship between the fibers and the matrix. If successful, the incorporation is abandoned, and the process returns to the first step. If it fails, the process proceeds to the next step. The third step is to evaluate the combination of fibers and aggregates. If successful, the incorporation is abandoned, and the process returns to the first step. If it fails, the process proceeds to the next step. The fourth step is to perform a "subtraction test" on the newly incorporated fiber and the set of all the fibers already incorporated. If the test is successful, the incorporation is abandoned and the process returns to the first step. If the test fails, the fiber is retained and added to the fiber set for the next "subtraction test". The above operation is repeated until a sufficient number of fibers are generated.

5. The method for generating a three-dimensional microstructure model of fiber-reinforced recycled concrete based on Boolean operations according to claim 1, characterized in that: In step 4, fiber models that meet various requirements are generated. Geometrically, these include straight, corrugated, and hooked shapes, and the shape parameters can be arbitrarily set. For different fibers, their shape parameters, including fiber length, are set separately. l and diameter d For corrugated fibers, this also includes the number of corrugations. n and ripple width w 1; For hooked fibers, this further includes the length of the hook. l 2 and width w 2; Based on model type, it includes 1-dimensional linear units and 3-dimensional solid units.

6. A system for generating a three-dimensional microscopic model of fiber-reinforced recycled concrete based on Boolean operations, characterized in that, include: The matrix generation section generates a three-dimensional micro-random aggregate model of recycled concrete with corresponding shape and size based on the information of the fiber-reinforced recycled concrete to be simulated. The aggregate generation section generates coarse aggregates within each particle size range based on the aggregate gradation of fiber-reinforced recycled concrete. Old mortar generation section: By imparting material properties, old mortar is applied to the surface of coarse aggregate; The fiber generation section randomly generates fibers in the three-dimensional microscopic model of recycled concrete. The Boolean operation-based three-dimensional microstructure model generation system for fiber-reinforced recycled concrete is used to perform the steps in the Boolean operation-based three-dimensional microstructure model generation method for fiber-reinforced recycled concrete as described in any one of claims 1-5.

7. The system for generating a three-dimensional microstructure model of fiber-reinforced recycled concrete based on Boolean operations according to claim 6, characterized in that, Also includes: The control unit is communicatively connected to the matrix generation unit, aggregate generation unit, old mortar generation unit, and fiber generation unit, and controls their operation. The input display unit is communicatively connected to the control unit and is used to allow the user to input operation commands and display the corresponding commands.

8. The system for generating a three-dimensional microstructure model of fiber-reinforced recycled concrete based on Boolean operations according to claim 6, characterized in that, Both the aggregate generation section and the fiber generation section perform subtraction tests on pairs of aggregates and pairs of fibers respectively, based on the idea of ​​Boolean operations.

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