A method, system, apparatus, and medium for improving interlayer shear performance of concrete

Abstract

The application discloses a method, system, device and medium for improving interlayer shear performance of concrete, and relates to the technical field of 3D printing concrete. The method comprises the following steps: acquiring concrete material parameters, steel fiber material parameters, size parameters and interlayer weak surface shear strength; creating a three-dimensional steel fiber concrete double-shear finite element model according to the concrete material parameters, the steel fiber material parameters, the size parameters and the interlayer weak surface shear strength; determining steel fiber layout parameters based on the three-dimensional steel fiber concrete double-shear finite element model; the steel fiber layout parameters comprise a cross-sectional area, a layout density and a length; and laying steel fibers between layers of 3D printing concrete according to the steel fiber layout parameters. The method can improve interlayer bonding performance and the overall load-carrying capacity of a component by laying steel fibers between layers.

Description

Technical Field

[0001] This invention relates to the field of 3D printed concrete technology, and in particular to a method, system, equipment and medium for improving the interlayer shear properties of concrete. Background Technology

[0002] 3D printed concrete is a formless additive manufacturing process that uses computer-controlled machinery to precisely place materials and accumulate them layer by layer along a pre-set printing path. Compared to traditional concrete construction methods, 3D printed concrete does not require formwork, offering advantages such as convenient construction, aesthetically pleasing appearance, low cost, and short construction period. It can greatly promote the mechanization, intelligence, and personalization of the construction industry, thus possessing significant development potential.

[0003] With the application of 3D printed concrete, due to its construction characteristics, the material deposition process relies solely on gravity without external vibration, resulting in a lack of fusion between continuously printed concrete strips. As surface moisture evaporates, water migration occurs between the concrete strips, leading to air trapping or closure between layers. This results in uneven deposition of the printed material, higher porosity, and more large pores between layers. Under load, stress concentration easily occurs at these pores, reducing interlayer bond strength and forming weak interlayer surfaces. To address this issue, Wu Lei et al. studied the effect of applying different interlayer interface agents on weak interlayer surfaces, showing that modified acrylic emulsion significantly improved the bonding performance of weak interlayer surfaces. Xu Hui et al. analyzed the influence mechanism of weak interlayer surfaces by considering printing process parameters and statistically analyzing domestic and international experimental data. Their results showed that optimizing three controllable printing process parameters—printing time interval, nozzle parameters, and printing speed—improves interlayer bonding performance. Marchment et al. designed a dual-nozzle printhead that can lay a 1mm thick layer of cementitious material between layers. Their results showed that laying a 1mm thick layer of cementitious material increases the interlayer bonding area, reduces interlayer porosity, and thus increases interlayer bond strength. Hosseini et al. applied a novel polymer mortar bonding layer composed of sulfur and black carbon between the layers, and the results showed that it improved the interlayer bonding strength.

[0004] In summary, the improvement of weak interlayer surfaces is mainly achieved by optimizing the printing process and developing modified materials to improve interlayer bonding performance. Although some progress has been made, steel fibers have not been incorporated, resulting in limited improvement in interlayer bonding performance and failing to enhance the overall load-bearing capacity of the component. Summary of the Invention

[0005] The purpose of this invention is to provide a method, system, device and medium for improving the interlayer shear properties of concrete, thereby improving interlayer bonding performance and the overall load-bearing capacity of the component by laying steel fibers between the layers.

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

[0007] A method for improving the interlayer shear properties of concrete includes:

[0008] Obtain concrete material parameters, steel fiber material parameters, dimensional parameters, and interlayer weak surface shear strength;

[0009] A three-dimensional steel fiber reinforced concrete double shear finite element model is created based on the concrete material parameters, the steel fiber material parameters, the dimensional parameters, and the interlayer weak surface shear strength.

[0010] The steel fiber layout parameters are determined based on the three-dimensional steel fiber reinforced concrete double shear finite element model; the steel fiber layout parameters include: cross-sectional area, layout density, and length;

[0011] According to the steel fiber layout parameters, steel fibers are laid between the layers of 3D printed concrete.

[0012] Optionally, a three-dimensional steel fiber reinforced concrete double-shear finite element model is created based on the concrete material parameters, the steel fiber material parameters, the dimensional parameters, and the interlayer weak surface shear strength, specifically including:

[0013] Create a concrete material constitutive model and a steel fiber material constitutive model based on the concrete material parameters and the steel fiber material parameters;

[0014] A three-dimensional steel fiber reinforced concrete double shear finite element model is created based on the constitutive model of the concrete material, the constitutive model of the steel fiber material, the dimensional parameters, and the interlayer weak surface shear strength.

[0015] Optionally, the constitutive model of the concrete material is a multilinear isotropic strengthening model; the constitutive model of the steel fiber material is a bilinear kinematic strengthening model.

[0016] Optionally, the steel fiber placement parameters are determined based on the three-dimensional steel fiber reinforced concrete double shear finite element model, specifically including:

[0017] The planned layout parameters are input into the three-dimensional steel fiber reinforced concrete double shear finite element model to obtain the maximum shear strength of the interlayer weak surface;

[0018] Determine whether the maximum shear strength of the interlaminar weak surface is within the target strength range, and obtain the determination result;

[0019] If the judgment result is negative, then adjust the parameters in the planned layout parameters according to the set order, and return to the step "input the planned layout parameters into the three-dimensional steel fiber reinforced concrete double shear finite element model to obtain the maximum shear strength of the interlayer weak surface";

[0020] If the judgment result is yes, then the planned deployment parameters are determined as steel fiber deployment parameters.

[0021] Optionally, the setting order is determined based on the three-dimensional steel fiber reinforced concrete double shear finite element model, using different parameters as influencing variables, through double shear failure simulation experiments; the setting order characterizes the degree of influence of each parameter on the shear resistance of the interlayer weak surface.

[0022] Optionally, the setting order is: cross-sectional area takes precedence over layout density, and layout density takes precedence over length.

[0023] Optionally, the three-dimensional steel fiber reinforced concrete double shear finite element model is created based on the Ansys parametric language.

[0024] A system for improving the interlayer shear properties of concrete includes:

[0025] The parameter acquisition module is used to acquire concrete material parameters, steel fiber material parameters, dimensional parameters, and interlayer weak surface shear strength.

[0026] The model creation module is used to create a three-dimensional steel fiber reinforced concrete double shear finite element model based on the concrete material parameters, the steel fiber material parameters, the dimensional parameters, and the interlayer weak surface shear strength.

[0027] The layout parameter determination module is used to determine the steel fiber layout parameters based on the three-dimensional steel fiber reinforced concrete double shear finite element model; the steel fiber layout parameters include: cross-sectional area, layout density, and length;

[0028] A steel fiber placement module is used to place steel fibers between layers of 3D printed concrete according to the steel fiber placement parameters.

[0029] An electronic device includes a memory and a processor, the memory storing a computer program, and the processor running the computer program to cause the electronic device to perform the above-described method for improving the interlayer shear resistance of concrete.

[0030] A computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method for improving the interlayer shear properties of concrete.

[0031] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0032] The method for improving the interlayer shear resistance of concrete provided by the present invention not only inhibits the development of interlayer cracks and bears the shear force at the cracks by arranging steel fibers in the interlayer, thus improving the interlayer bonding performance, but also inhibits the extension of cracks into the concrete layer, thereby improving the overall load-bearing capacity of the component. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 A flowchart of a method for improving the interlayer shear properties of concrete provided by the present invention;

[0035] Figure 2 A schematic diagram of the geometric model of steel fiber reinforced concrete provided by the present invention;

[0036] Figure 3 A schematic diagram showing the relative positions of the steel fibers provided by this invention;

[0037] Figure 4 A comparison diagram of the maximum shear strength of the interlaminar weak surface with different steel fiber cross-sectional areas provided by the present invention;

[0038] Figure 5 A comparison diagram of the maximum shear strength of interlaminar weak surfaces with different steel fiber density provided by this invention;

[0039] Figure 6 A comparison diagram of the maximum shear strength of interlaminar weak surfaces with different steel fiber lengths provided by this invention;

[0040] Figure 7 This is a schematic diagram of crack development in the absence of steel fibers, provided by the present invention.

[0041] Figure 8 A schematic diagram of crack development in the presence of steel fibers, provided by the present invention;

[0042] Figure 9 A comparison diagram of the maximum shear strength increment of interlaminar weak surfaces for different steel fiber influence variables provided by this invention.

[0043] Symbol explanation:

[0044] Rigid pad block—201, steel fiber—202, interlayer weak surface—203, 3D printed concrete block—204. Detailed Implementation

[0045] 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.

[0046] In recent years, steel fibers have been increasingly used in concrete components. The combination of steel fibers and concrete creates a complementary advantage, greatly improving the performance of the material itself. The purpose of this invention is to provide a method, system, device, and medium for improving the interlayer shear properties of concrete, thereby enhancing interlayer bonding performance and the overall load-bearing capacity of the component by arranging steel fibers between layers.

[0047] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0048] Example 1

[0049] This invention provides a method for improving the interlayer shear properties of concrete, such as... Figure 1 As shown, it includes:

[0050] Step S1: Obtain concrete material parameters, steel fiber material parameters, dimensional parameters, and interlayer weak surface shear strength.

[0051] Step S2: Create a three-dimensional steel fiber reinforced concrete double shear finite element model based on the concrete material parameters, the steel fiber material parameters, the dimensional parameters, and the interlayer weak surface shear strength.

[0052] Step S2 specifically includes:

[0053] Step S21: Create a constitutive model for the concrete material and a constitutive model for the steel fiber material based on the concrete material parameters and the steel fiber material parameters. The concrete material constitutive model is a multilinear isotropic hardening model; the steel fiber material constitutive model is a bilinear kinematic hardening model.

[0054] Specifically, the constitutive model of 3D printed concrete adopts the multilinear isotropic hardening model (MISO). The constitutive relationship of concrete, i.e., the uniaxial compressive stress-strain relationship, adopts the German Rush stress-strain mathematical model. The elastic modulus of concrete must be consistent with the slope of the first point of the curve, and the Poisson's ratio is μ = 0.2. The Rush stress-strain relationship expression is as follows:

[0055]

[0056] In the formula: f c ε is the uniaxial compressive strength; ε0 is the peak strain; ε u σ represents the ultimate compressive strain; σ represents the stress in the concrete material; and ε represents the strain in the concrete material.

[0057] The failure criterion for concrete adopts the William-Warnke 5-parameter model, and the expression is as follows:

[0058]

[0059] In the formula: F is the principal stress state function, and S is the failure surface function determined by the concrete material. Taking C50 concrete as an example for simulation, its uniaxial compressive strength f c =23.1 MPa, uniaxial tensile strength f t =1.89 MPa. Both of the above parameters were obtained by consulting the literature.

[0060] The steel fiber adopts a bilinear kinematic hardening model (BKIN), and the stress-strain relationship is approximated as that of the steel reinforcement. An ideal elastic-plastic model is selected, and its expression is as follows:

[0061]

[0062] Where: E is the elastic modulus of steel fiber; f y ε is the yield strength of steel fiber; y For yield strain; σ s For the stress of steel fiber materials; ε s Let f be the strain of the steel fiber material. Specifically, the elastic modulus of the steel fiber is E = 2.1e5 MPa, Poisson's ratio is μ = 0.3, and the yield strength is f. y =400Mpa.

[0063] In addition, the elastic modulus of the pad is E = 2e6 MPa, and the Poisson's ratio is μ = 0.3.

[0064] Step S22: Based on the constitutive model of the concrete material, the constitutive model of the steel fiber material, the dimensional parameters, and the interlayer weak surface shear strength, create a three-dimensional steel fiber reinforced concrete double-shear finite element model. The three-dimensional steel fiber reinforced concrete double-shear finite element model is created using the Ansys parametric language. The dimensional parameters include the dimensional parameters of the rigid pad and the 3D printed concrete block.

[0065] Steel fiber reinforced concrete double shear model, such as Figure 2 and Figure 3 As shown, where, Figure 2 This is a schematic diagram of the geometric model of steel fiber reinforced concrete. Figure 3This is a schematic diagram showing the relative positions of the steel fibers. The 3D-printed concrete block 204 is simulated using Solid65 elements, while the steel fiber 202 and rigid pad 201 are simulated using Solid185 elements. The interlayer weak surface 203 is simulated using Combin39 elements. The z-axis of the coordinate system is defined as the direction along the print head's movement path, the x-axis is defined as the direction of layer increase, and the y-axis is perpendicular to the xoz plane. Three 3D-printed concrete blocks 204 with dimensions of 100mm in the z-direction, 64mm in the y-direction, and 20mm in the x-direction, and three rigid pads 201 with dimensions of 100mm in the z-direction, 4mm in the y-direction, and 20mm in the x-direction are created. The mesh of the 3D-printed concrete block 204 is 2mm in the x-direction and 4mm in both the y and z directions, while the mesh of the rigid pad 201 is 4mm in all three directions. The bottom surfaces of the pads at both ends are fully constrained, and a vertically downward displacement load is applied to the top surface of the middle pad through a reference point. Before the steel fiber is laid, the maximum shear strength f of the weak interlaminar surface 203 is measured. τ The input values ​​are taken as 1.5 MPa, 2 MPa, and 2.5 MPa respectively in the program for calculation, f τ The input values ​​and the output values ​​after solving are shown in Table 1.

[0066] Table 1 Different f τ Comparison of input values ​​and output values ​​after solving

[0067] <![CDATA[f τ Input value / MPa]]> 1.5 2 2.5 fτ output value / MPa 1.50439 2.0016 2.48963

[0068] Table 1 shows that there are slight errors between the input values ​​and the solved output values, all of which are controlled within 0.5%, indicating that the simulation of weak interlayer surfaces using this element is valid.

[0069] The variables affecting the steel fibers studied are cross-sectional area, fiber density, and length. The cross-sectional area is represented by S. A This indicates that the unit is mm. 2 Length is represented by l, and the unit is mm. Fiber density refers to the number of steel fibers laid per unit area between 3D printed concrete layers, represented by pA, and the unit is pi / m². 2 Steel fibers perpendicular to the interface are uniformly distributed at the interface, connecting adjacent concrete layers. A grid is formed with a length of 2mm in the x-direction. Wang Jiahe et al. studied the pull-out behavior of steel wires from concrete, showing that the larger the angle between the pull-out direction and the embedment direction, the greater the pull-out ultimate bearing capacity. In this invention, steel fibers are evenly distributed in the interlayer with the interlayer weak surface as the boundary. The angle between the steel fiber and the plane containing the interlayer weak surface is 90°. The angle between the stress direction of the steel fiber and the embedment direction is relatively large. Based on the above theory, it is assumed that the steel fiber and concrete have good adhesion; therefore, bond slip is not considered.

[0070] Step S3: Determine the steel fiber layout parameters based on the three-dimensional steel fiber reinforced concrete double shear finite element model; the steel fiber layout parameters include: cross-sectional area, layout density and length.

[0071] Step S3 specifically includes:

[0072] Step S31: Input the planned layout parameters into the three-dimensional steel fiber reinforced concrete double shear finite element model to obtain the maximum shear strength of the interlayer weak surface.

[0073] Step S32: Determine whether the maximum shear strength of the interlaminar weak surface is within the target strength range, and obtain the determination result.

[0074] Step S33: If the judgment result is negative, adjust the parameters in the planned layout parameters according to the set order, and return to step S31. The set order is determined based on the three-dimensional steel fiber reinforced concrete double shear finite element model, using different parameters as influencing variables, through double shear failure simulation experiments; the set order characterizes the degree of influence of each parameter on the shear resistance of the interlayer weak surface.

[0075] Step S34: If the judgment result is yes, then the planned layout parameters are determined as steel fiber layout parameters.

[0076] Preferably, the setting order is: cross-sectional area takes precedence over layout density, and layout density takes precedence over length.

[0077] Specifically, based on the three-dimensional steel fiber reinforced concrete double shear finite element model, the steps for conducting a double shear failure simulation experiment with different parameters as influencing variables are as follows.

[0078] Three sets of steel fiber influence variables were simulated in the order of cross-sectional area, density, and length. The placement parameter that maximizes the improvement of interlayer weak surface shear performance in the previous set was assigned to the simulation of the next set of influence variables, thus determining the steel fiber influence variable and placement parameter that maximizes the improvement of interlayer weak surface shear performance. The 3D printed concrete material parameters were set according to C50 concrete, whose maximum shear strength in cast-in-place concrete is 2.9 MPa. Studies show that the maximum shear strength of the interlayer weak surface is reduced by 22%–30% compared to cast-in-place concrete; therefore, the maximum shear strength of the interlayer weak surface is calculated as 70% of that of cast-in-place concrete. τ The input value is approximated as 2 MPa. During data analysis, to more accurately compare the changes in shear performance of the interlaminar weak surface before and after steel fiber placement, the maximum shear strength of the interlaminar weak surface without steel fiber is taken as the output value f from Table 1. τ =2.0016 MPa to reduce error.

[0079] First, we simulated double shear failure under the influence of cross-sectional area variables.

[0080] Twelve steel fibers are laid between the layers, i.e., a density ρ A =1875pi / m 2 Under the condition that the length l = 16 mm remains constant, the influence of cross-sectional area on the shear resistance of the interlaminar weak surface was studied. Four different steel fiber cross-sectional areas were used for finite element simulation. The specific steel fiber placement parameters and calculation results are shown in Table 2. The maximum shear strength of the interlaminar weak surface under the double shear model for different steel fiber cross-sectional areas is shown in Table 2. Figure 4 As shown. The maximum shear strength of the interlaminar weak surface increases with the increase of the cross-sectional area of ​​the steel fiber. When S A =0.5mm 2 When the time is maximum, f τ =2.0558 MPa, compared to without steel fiber f τ It increased by 5.42%. Among them, the experimental values ​​of various steel fiber layout parameters were artificially defined based on the existing material dimensions, the convenience of modeling, and the requirement to achieve the research law.

[0081] Table 2. Layout parameters and calculation results of steel fibers with different cross-sectional areas.

[0082]

[0083] Secondly, we simulated the double shear failure under the influence of density variables.

[0084] In the cross-sectional area S of the steel fiber A =0.5mm 2 Under the condition that the length l = 16 mm remains constant, the influence of steel fiber density on the shear resistance of the interlaminar weak surface was studied. Seven different steel fiber densities were set up for finite element simulation. The density values ​​were calculated based on the ratio of 12, 16, 20, 24, 28, 32, and 40 fibers to the interface area at the same interlaminar interface, respectively, in the double shear model described above. The specific steel fiber placement parameters and calculation results are shown in Table 3. The maximum shear strength of the interlaminar weak surface under the double shear model for different steel fiber densities is shown in Table 3. Figure 5 As shown. The maximum shear strength of the interlaminar weak surface increases with the increase of steel fiber density, when ρ A =6250pi / m 2 When the time is maximum, f τ =2.1844 MPa, compared to without steel fiber f τ It increased by 9.13%.

[0085] Table 3. Parameters and calculation results for steel fiber layout at different densities.

[0086]

[0087] Finally, we simulated double shear failure under the influence of length variables.

[0088] In the cross-sectional area S of the steel fiber A =0.5mm 2 , deployment density ρ A =6250pi / m 2 Under the condition of keeping constant, the effect of steel fiber length on the shear resistance of the interlaminar weak surface was studied. Three different steel fiber lengths were used in finite element simulations. The specific steel fiber placement parameters and calculation results are shown in Table 4. The maximum shear strength of the interlaminar weak surface under the double shear model for different steel fiber lengths is shown in Table 4. Figure 6 As shown, the maximum shear strength of the interlaminar weak surface first increases and then remains constant with the increase of steel fiber length, reaching a maximum value when the length l = 16 mm. τ =2.1844 MPa, compared to without steel fiber f τ It increased by 9.13%.

[0089] Table 4. Layout parameters and calculation results for steel fibers of different lengths

[0090]

[0091]

[0092] Based on the above simulation steps, the toughening and crack-resistant effect of steel fibers on the specimen can be revealed, as follows.

[0093] Taking the simulation that showed the greatest improvement in shear resistance of the interlaminar weak surface as an example, the crack development in the case without steel fibers and the case with steel fibers are respectively referred to Figure 7 and Figure 8It can be observed that without steel fibers, stress concentration easily occurs at the tips of interlayer pores, leading to initial cracking and stress redistribution in the surrounding area. The stress state of adjacent pores is also more significantly disturbed, further causing stress concentration at the pore tips. This results in cracks connecting the interlayer pores, ultimately leading to the failure of the weak interlayer surface. With steel fibers placed in the interlayer, when stress concentration occurs at the pore tips and cracks initiate, the steel fibers can inhibit crack development and prevent direct connection to the interlayer pores. In the initiation stage, cracks are fewer and concentrated in the interlayer; a higher fiber density can inhibit the development of more interlayer cracks. Therefore, the shear resistance of the weak interlayer surface increases with increasing fiber density. As the load continues to increase and numerous cracks appear in the interlayer, the steel fibers act as a bridge, transferring and bearing the shear force at the cracks. At this point, a larger cross-sectional area can bear and transfer a greater shear force. Simultaneously, cracks can extend into the concrete, affecting the bond between the steel fibers and the concrete. Increasing the length can suppress crack propagation, but because the interlayer weak surface has weak shear resistance and the deformation capacity of concrete is far less than that of steel fibers, the interlayer weak surface is already damaged even if the crack does not extend into the interior and break the bond between the steel fibers and the concrete. Therefore, the shear resistance of the interlayer weak surface increases with the increase of cross-sectional area. With the increase of length, it first increases and then remains constant.

[0094] To save costs and fully utilize the mechanical properties of steel fibers, it is necessary to analyze the influence of various variables on the shear strength of the interlaminar weak surface and determine the optimal steel fiber placement parameters. Therefore, the concept of steel fiber volume fraction (η) is introduced, which is the ratio of the volume of steel fibers contained in the concrete block to the volume of the concrete block. By comparing the increase in the maximum shear strength of the interlaminar weak surface with each increase in steel fiber volume fraction, the influence of each variable is analyzed. For the cross-sectional area, Table 2 shows that an average increase of 1 mm... 3 (η=7.81E-6) The shear strength of the interlaminar weak surface increases by 5.9028E-4 MPa when steel fibers are used, denoted by △P, with units of MPa / mm. 3 That is, △P 截面积 =5.9028E-4 MPa / mm 3 Similarly, from Table 3, we can obtain △P. 布设密度 =5.7416E-4 MPa / mm 3 For interlayer weak surfaces with a length l exceeding 16 mm, the shear resistance is no longer improved. Therefore, from the first two sets of data in Table 4, we can obtain ΔP. 长度 =7.5E-6 MPa / mm 3 For every increase in the volume fraction η = 7.81E-6 of steel fibers, the maximum shear strength of the interlaminar weak surface increases for different variables as follows: Figure 9 As shown in the figure. In summary, length has a relatively small impact, while cross-sectional area and layout density have a larger impact.

[0095] Step S4: According to the steel fiber layout parameters, steel fibers are laid between the layers of 3D printed concrete.

[0096] Specifically, when 3D printing a wall, the weak points between concrete layers are the weakest parts of the entire wall. By placing steel fibers between the layers, the bonding performance between layers can be enhanced. In engineering, the actual parameters, dimensions, and shear strength of the weak points in the interlayer of the 3D-printed concrete can be input into the program. Then, the planned cross-sectional area, density, and length of the steel fibers are input into the program for calculation. The results are then checked to determine if the engineering requirements are met. If the requirements are not met, the simulation is repeated by changing the placement parameters until the requirements are met. This simulation method improves efficiency and reduces time costs. Furthermore, a comparison of the influence of cross-sectional area, density, and length on the shear performance of the weak points in the interlayer shows that cross-sectional area and density have a significant impact, with cross-sectional area having the greatest impact, while length has the least impact. This principle can guide the placement of steel fibers by first adjusting the cross-sectional area and then adjusting the density, thereby saving costs.

[0097] This invention utilizes Ansys large-scale finite element software for nonlinear analysis to study the influence of three different steel fiber variables—cross-sectional area, fiber density, and fiber length—on the shear resistance of weak interlayer surfaces in 3D-printed concrete from a microscopic perspective. The study reveals the inhibitory effect of steel fibers on damage and cracking in these weak interlayer surfaces. Existing research on improving weak interlayer surfaces mainly focuses on optimizing the printing process and developing modified materials to enhance interlayer bonding performance. This invention, however, involves placing steel fibers in the interlayer, which not only inhibits crack development and bears shear force at crack locations, improving interlayer bonding performance, but also inhibits crack extension into the concrete layer, thereby enhancing the overall load-bearing capacity of the component.

[0098] Example 2

[0099] In order to implement the method corresponding to Embodiment 1 above and achieve the corresponding functions and technical effects, a system for improving the interlayer shear performance of concrete is provided below, comprising:

[0100] The parameter acquisition module is used to acquire concrete material parameters, steel fiber material parameters, dimensional parameters, and interlayer weak surface shear strength.

[0101] The model creation module is used to create a three-dimensional steel fiber reinforced concrete double shear finite element model based on the concrete material parameters, the steel fiber material parameters, the dimensional parameters, and the interlayer weak surface shear strength.

[0102] The layout parameter determination module is used to determine the steel fiber layout parameters based on the three-dimensional steel fiber reinforced concrete double shear finite element model; the steel fiber layout parameters include: cross-sectional area, layout density and length.

[0103] A steel fiber placement module is used to place steel fibers between layers of 3D printed concrete according to the steel fiber placement parameters.

[0104] Example 3

[0105] This invention also provides an electronic device, including a memory and a processor. The memory stores a computer program, and the processor runs the computer program to enable the electronic device to perform the method for improving the interlayer shear resistance of concrete as described in Embodiment 1. The electronic device may be a server.

[0106] In addition, the present invention also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the method for improving the interlayer shear resistance of concrete in Embodiment 1.

[0107] In summary, this invention provides a method, system, equipment, and medium for improving the interlayer shear properties of concrete, exploring the influence of steel fiber placement on interlayer shear properties at a microscopic level. Based on the Ansys parametric language, a three-dimensional steel fiber reinforced concrete bi-shear finite element model was established, consisting of steel fibers, 3D-printed concrete, and the concrete interlayer interface. Finite element simulations were used to reveal the toughening and crack-resistant effect of steel fibers on the specimens and to investigate bi-shear failure under three different steel fiber influence variables: cross-sectional area, placement density, and length.

[0108] 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 systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be referred to the method section.

[0109] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for improving the interlayer shear properties of concrete, characterized in that, include: Obtain concrete material parameters, steel fiber material parameters, dimensional parameters, and interlayer weak surface shear strength; A three-dimensional steel fiber reinforced concrete double-shear finite element model is created based on the concrete material parameters, the steel fiber material parameters, the dimensional parameters, and the interlayer weak surface shear strength. Specifically, this creation includes: creating a concrete material constitutive model and a steel fiber material constitutive model based on the concrete material parameters and steel fiber material parameters; and creating a three-dimensional steel fiber reinforced concrete double-shear finite element model based on the concrete material constitutive model, the steel fiber material constitutive model, the dimensional parameters, and the interlayer weak surface shear strength. The steel fiber placement parameters are determined based on the three-dimensional steel fiber reinforced concrete double shear finite element model. These parameters include cross-sectional area, placement density, and length. Specifically, determining the steel fiber placement parameters involves: inputting the planned placement parameters into the three-dimensional steel fiber reinforced concrete double shear finite element model to obtain the maximum shear strength of the inter-layer weak surface; determining whether the maximum shear strength of the inter-layer weak surface is within the target strength range, and obtaining the determination result; if the determination result is negative, adjusting each of the planned placement parameters according to a set order. The parameters are entered into the three-dimensional steel fiber reinforced concrete double shear finite element model to obtain the maximum shear strength of the inter-story weak surface. If the judgment result is yes, the planned layout parameters are determined as steel fiber layout parameters. The setting order is determined based on the three-dimensional steel fiber reinforced concrete double shear finite element model, using different parameters as influencing variables, and conducting double shear failure simulation experiments. The setting order characterizes the degree of influence of each parameter on the shear performance of the inter-story weak surface. The setting order is: cross-sectional area takes precedence over layout density, and layout density takes precedence over length. According to the steel fiber layout parameters, steel fibers are laid between the layers of 3D printed concrete.

2. The method for improving the interlayer shear properties of concrete according to claim 1, characterized in that, The constitutive model of the concrete material is a multilinear isotropic strengthening model; the constitutive model of the steel fiber material is a bilinear kinematic strengthening model.

3. The method for improving the interlayer shear properties of concrete according to claim 1, characterized in that, The three-dimensional steel fiber reinforced concrete double shear finite element model was created using the Ansys parametric language.

4. A system for improving the interlayer shear resistance of concrete, characterized in that, include: The parameter acquisition module is used to acquire concrete material parameters, steel fiber material parameters, dimensional parameters, and interlayer weak surface shear strength. The model creation module is used to create a three-dimensional steel fiber reinforced concrete double-shear finite element model based on the concrete material parameters, the steel fiber material parameters, the dimensional parameters, and the interlayer weak surface shear strength. Specifically, this includes: creating a concrete material constitutive model and a steel fiber material constitutive model based on the concrete material parameters and steel fiber material parameters; and creating a three-dimensional steel fiber reinforced concrete double-shear finite element model based on the concrete material constitutive model, the steel fiber material constitutive model, the dimensional parameters, and the interlayer weak surface shear strength. The fiber placement parameter determination module is used to determine the fiber placement parameters based on the three-dimensional steel fiber reinforced concrete double shear finite element model. The fiber placement parameters include cross-sectional area, placement density, and length. Specifically, determining the fiber placement parameters based on the three-dimensional steel fiber reinforced concrete double shear finite element model involves: inputting the planned placement parameters into the three-dimensional steel fiber reinforced concrete double shear finite element model to obtain the maximum shear strength of the inter-layer weak surface; determining whether the maximum shear strength of the inter-layer weak surface is within the target strength range and obtaining a determination result; if the determination result is negative, adjusting the planned placement according to a set sequence. The parameters in the parameters are selected, and the process returns to the step "Input the planned layout parameters into the three-dimensional steel fiber reinforced concrete double shear finite element model to obtain the maximum shear strength of the inter-story weak surface"; if the judgment result is yes, then the planned layout parameters are determined as steel fiber layout parameters; the setting order is determined based on the three-dimensional steel fiber reinforced concrete double shear finite element model, using different parameters as influencing variables, and conducting double shear failure simulation experiments; the setting order characterizes the degree of influence of each parameter on the shear performance of the inter-story weak surface; the setting order is: cross-sectional area takes precedence over layout density, and layout density takes precedence over length; A steel fiber placement module is used to place steel fibers between layers of 3D printed concrete according to the steel fiber placement parameters.

5. An electronic device, characterized in that, The device includes a memory and a processor, the memory being used to store a computer program, and the processor running the computer program to cause the electronic device to perform the method for improving the interlayer shear properties of concrete as described in any one of claims 1 to 3.

6. A computer-readable storage medium, characterized in that, It stores a computer program that, when executed by a processor, implements the method for improving the interlayer shear properties of concrete as described in any one of claims 1 to 3.

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