3d printed modular component assembly joint structure and method based on engineered cementitious composite

Abstract

This invention relates to a 3D-printed modular component assembly and connection structure and method based on engineering cement-based composite materials, belonging to the field of architectural 3D printing. It includes a first module unit and a second module unit, with alternating protrusions and recesses at the ends of each module unit. When the first and second module units are assembled, the protrusions of one module unit embed into the recesses of the other, creating multiple closed cavities extending along the connection direction at the mating interface. These closed cavities are filled with engineering cement-based composite materials, thus constructing multiple independent or weakly coupled flexible connection units at the connection interface. Under external loads or uneven foundation settlement, each flexible connection unit can undergo asynchronous deformation, and stress dispersion and energy dissipation are achieved through the strain hardening and multi-crack characteristics of the engineering cement-based composite material, effectively reducing stress concentration at the connection interface and preventing brittle failure.

Description

Technical Field

[0001] This invention relates to a 3D-printed modular component assembly and connection structure and method based on engineering cement-based composite materials, belonging to the technical field of prefabricated buildings and 3D-printed concrete structures. Background Technology

[0002] With the advancement of smart grid construction, substations are gradually developing towards modularization, rapid deployment, and green technology. Due to its advantages such as high construction efficiency, high material utilization, and the ability to achieve integrated molding of complex structures, 3D printing technology has been gradually applied to the prefabrication and on-site construction of substation components. Currently, substation foundation components, wall components, and equipment supports can all be prepared using 3D printed concrete, thereby improving construction efficiency and reducing labor costs.

[0003] However, during modular assembly, the connection points between components remain weak links in the structural system. Especially under conditions of soft soil foundations, heavy equipment loads, or complex geological conditions, uneven settlement of the foundation can easily occur, causing the connection areas to bear large tensile, compressive, and shear stresses, which can easily lead to cracking or even failure.

[0004] Existing connection methods for 3D printed components mainly include cast-in-place concrete connections, rebar lap splices, or shear keys. These connection methods typically rely on continuous rigid contact interfaces to transfer loads, which not only involves complex construction procedures and low standardization, but also easily leads to stress concentration at the interface when subjected to uneven deformation, thus causing brittle failure and failing to meet the deformation adaptability requirements of modular structures.

[0005] Engineering cement-based composites are highly ductile cement-based materials with strain-hardening properties. Under tensile conditions, they can form multiple microcracks and continue to bear loads, exhibiting excellent deformation capacity and energy dissipation capacity. Therefore, engineering cement-based composites have been applied in seismic structures and reinforcement projects. However, current technologies have not yet integrated the structural design of the connection interface between engineering cement-based composites and 3D-printed modular components, particularly lacking a connection technology solution that can achieve deformation coordination through the construction of discrete connection units.

[0006] Therefore, there is an urgent need for a new modular component connection structure that can effectively disperse stress and adapt to uneven settlement while ensuring connection strength, so as to meet the actual engineering needs of 3D printed substation structures. Summary of the Invention

[0007] This invention provides a 3D-printed modular component assembly and connection structure and method based on engineering cement-based composite materials. By setting an undulating complementary interface structure at the docking ends of the modular units, multiple closed cavities extending along the connection direction are formed in the docking area after two structurally identical modular units are assembled relative to each other. The closed cavities are filled with engineering cement-based composite materials, thereby constructing multiple independent or weakly coupled flexible connection units at the connection interface. Under external loads or uneven foundation settlement, each flexible connection unit can undergo asynchronous deformation, and stress dispersion and energy dissipation are achieved through the strain hardening and multi-crack characteristics of the engineering cement-based composite materials. This effectively reduces stress concentration at the connection interface, avoids brittle failure, and improves the overall deformation adaptability and connection reliability of the structure.

[0008] The technical solution of the present invention is as follows:

[0009] A 3D-printed modular component assembly and connection structure based on engineering cement-based composite material includes a first module unit and a second module unit, wherein the first module unit and the second module unit are printed components with the same structure.

[0010] The end of the first module unit includes alternating protrusions and recesses with the same height. The sidewalls of adjacent protrusions form a lateral limiting structure, which can provide lateral constraint on the filling material after assembly. The protrusions and recesses of each module unit extend along the connection direction to form an undulating complementary interface structure.

[0011] Each protrusion has a notch at its end. When the first module unit and the second module unit are spliced ​​together, the protrusion of one module unit is embedded in the recess of the other module unit. The notch forms multiple closed cavities extending along the connection direction on the docking interface. Each closed cavity is distributed at intervals along the connection interface and each cavity is independent of the others.

[0012] The enclosed cavity is filled with engineering cement-based composite material (ECC). The enclosed cavity is formed by the enclosed parts of the protrusions and the depressions, thereby geometrically constraining the engineering cement-based composite material, so that each enclosed cavity acts as a relatively independent force-bearing unit when subjected to force.

[0013] Preferably, the shape of the enclosed cavity is rectangular, trapezoidal, semi-circular, or stepped.

[0014] Preferably, the engineering cement-based composite material (ECC) is prepared using cement, fly ash, fine sand and PVA fiber, with a fiber volume fraction of 1.5% to 2.0%.

[0015] Preferably, the ultimate tensile strain of the engineering cement-based composite material (ECC) is 6% to 10%, and multiple dispersed microcracks are formed when subjected to tension.

[0016] Engineering cement-based composite materials are filled in the closed cavities and contact gaps between modular units, forming multiple distributed flexible connection units after curing. Each flexible connection unit is a localized connection of engineering cement-based composite material filled within a single closed cavity and cured. Multiple flexible connection units together constitute the engineering cement-based composite material connection layer. Under stress, each flexible connection unit can undergo relatively independent local deformation, and through the strain hardening and multi-crack characteristics of the engineering cement-based composite material, it can achieve coordinated stress and deformation, thereby dispersing stress concentration at the connection interface and improving the overall deformation adaptability and connection reliability of the structure.

[0017] A construction method for the above-mentioned 3D-printed modular component assembly and connection structure based on engineering cement-based composite materials includes the following steps:

[0018] S1, the first module unit and the second module unit are prepared by 3D printing, with a printing layer height of 8-12 mm and a printing strip width of 24-36 mm; the end of each module unit is composed of alternating protrusions and recesses;

[0019] S2, the first module unit and the second module unit are misaligned and aligned and then assembled (the assembly process only requires embedding and does not require additional steel reinforcement connection), so that the protrusion of the first module unit is precisely embedded into the recess of the second module unit, forming multiple closed cavities on the mating surface.

[0020] S3. After assembly, the engineering cement-based composite material (ECC) is injected into the closed cavity. During the pouring process, slight vibration or self-leveling is used to ensure that the material fully fills the closed cavity.

[0021] S4, after pouring, should be naturally cured or covered for curing.

[0022] Preferably, the material of the printed component is 3D printed concrete.

[0023] Preferably, in step S2, the height of the protrusion is 150~250 mm, the width is 300 mm, and the distance between adjacent protrusions is 300 mm.

[0024] Preferably, in step S2, the height of the enclosed cavity is 80-100mm and the width is 120-150mm.

[0025] Preferably, in step S4, the curing time is 3 to 7 days to harden the engineering cement-based composite material.

[0026] During the service life of the structure, when uneven settlement of the foundation occurs or the structure is subjected to external loads, the flexible connection units formed in each closed cavity can undergo varying degrees of deformation. Due to the constraint effect of the lateral restraint structure, the engineering cement-based composite material mainly undergoes tensile and shear deformation within the cavity, and gradually releases stress through multi-slit cracking, thereby avoiding the formation of concentrated cracks at the connection interface.

[0027] Even if the engineered cement-based composite material in a local cavity cracks or is damaged, the remaining cavities can still bear the load, thus ensuring the stability of the overall connection structure.

[0028] This invention is applicable to the assembly and connection of 3D printed modular components such as substation foundations, equipment supports, and enclosure components.

[0029] For any details not covered in this invention, please refer to the prior art.

[0030] The beneficial effects of this invention are as follows:

[0031] This invention constructs an undulating complementary structure at the interface of modular units, creating multiple closed cavities extending along the connection direction after assembly. These cavities are filled with engineering cement-based composite material, forming multiple independent flexible connection units in the connection area. This structure transforms the traditional continuous rigid connection interface into a combined system of "discrete cavities and flexible filling." Under stress, each flexible connection unit can undergo relatively independent local deformation, while also achieving coordinated stress distribution and overall deformation through the strain hardening and multi-crack characteristics of the engineering cement-based composite material, effectively dispersing stress and dissipating energy. Because each flexible connection unit has relatively independent stress characteristics, damage to a local unit will not lead to overall failure, significantly improving the structure's safety and redundancy.

[0032] Furthermore, the connection structure of this invention does not rely on complex steel reinforcement connections or cast-in-place construction. The modular units can achieve standardized prefabrication and rapid assembly, exhibiting excellent engineering applicability. In summary, this invention achieves a transformation from rigid overall stress to distributed flexible collaborative stress in the connection mechanism, significantly improving the deformation adaptability and service reliability of the structure, and is particularly suitable for engineering scenarios with uneven settlement or complex stress conditions. Attached Figure Description

[0033] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute an undue limitation of this application.

[0034] Figure 1 This is a schematic diagram of the structure of the first module unit and the second module unit of the present invention before they are assembled.

[0035] Figure 2 This is a schematic diagram of the structure after the first module unit and the second module unit of the present invention are assembled;

[0036] Figure 3 This is a schematic diagram of the closed cavity filling process in this invention;

[0037] Figure 4 This is a schematic diagram of a stepped structure for a closed cavity in one embodiment of the present invention;

[0038] Figure 5 This is a schematic diagram of a semi-circular structure for the enclosed cavity in one embodiment of the present invention;

[0039] Among them, 1-first module unit, 2-second module unit, 3-engineering cement-based composite material, 4-protrusion, 5-recess, 6-closed cavity, 7-flexible connection unit, 8-interface structure, 9-lateral limiting structure. Detailed Implementation

[0040] To enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. However, this is not the only description; all aspects not described in detail herein are based on conventional techniques in the art.

[0041] Example 1

[0042] A 3D-printed modular component assembly and connection structure based on engineering cement-based composite materials, such as... Figures 1 to 3 As shown, it includes a first module unit 1 and a second module unit 2, and the first module unit 1 and the second module unit 2 are printed components with the same structure;

[0043] The end of the first module unit 1 includes alternating protrusions 4 and recesses 5, with the same height for the protrusions 4 and recesses 5. The sidewalls of adjacent protrusions 4 form a lateral limiting structure 9, which can provide lateral constraint to the filling material after assembly. The protrusions and recesses of each module unit extend along the connection direction to form an undulating complementary interface structure 8.

[0044] Each protrusion 4 has a notch at its end. When the first module unit 1 and the second module unit 2 are spliced ​​together, the protrusion of one module unit is embedded in the recess of the other module unit. The notch forms multiple closed cavities 6 extending along the connection direction on the docking interface. Each closed cavity 6 is distributed at intervals along the connection interface and each closed cavity is independent of the others.

[0045] The closed cavity 6 is filled with engineering cement-based composite material 3. The closed cavity 6 is formed by the enclosed part and the recessed part, which geometrically constrains the engineering cement-based composite material, so that each closed cavity is a relatively independent force unit when subjected to force.

[0046] In this embodiment, the shape of the enclosed cavity 6 is rectangular;

[0047] The engineering cement-based composite material 3 is prepared using cement, fly ash, fine sand and PVA fiber, with a fiber volume fraction of 1.5% to 2.0%.

[0048] The ultimate tensile strain of the engineering cement-based composite material 3 is 6% to 10%, and multiple dispersed microcracks are formed when it is under tension.

[0049] Example 2

[0050] A 3D-printed modular component assembly and connection structure based on engineering cement-based composite materials, as described in Example 1, except that... Figure 4 As shown, the closed cavity 6 has a stepped shape.

[0051] Example 3

[0052] A 3D-printed modular component assembly and connection structure based on engineering cement-based composite materials, as described in Example 2, differs in that... Figure 5 As shown, the closed cavity 6 is semi-circular in shape.

[0053] Example 4

[0054] A construction method for assembling and connecting 3D-printed modular components based on engineering cement-based composite materials includes the following steps:

[0055] S1. The first module unit 1 and the second module unit 2 are prepared by 3D printing. The material of the printed components is 3D printed concrete. The printing layer height is 8-12 mm and the printing strip width is 24-36 mm. The end of each module unit is composed of alternating protrusions and recesses.

[0056] S2, after the first module unit 1 and the second module unit 2 are misaligned and aligned, they are assembled (the assembly process only requires embedding and does not require additional steel reinforcement connection), so that the protrusion of the first module unit is precisely embedded into the recess of the second module unit, forming multiple closed cavities 6 on the mating surface.

[0057] The height of the protrusion 4 is 200 mm and the width is 300 mm. The distance between adjacent protrusions 4 is 300 mm. The height of the closed cavity 6 is 90 mm and the width is 130 mm.

[0058] S3. After assembly, inject the engineering cement-based composite material 3 into the closed cavity 6 (it can be injected at the splice joint). During the pouring process, use slight vibration or self-leveling to fully fill the closed cavity with the material. For multiple independent closed cavities 6 in different locations, the filling can be completed by pouring one by one or pouring simultaneously.

[0059] S4, after pouring, is naturally cured or covered for 3 to 7 days to harden the cement-based composite material.

[0060] During the service life of the structure, when uneven settlement of the foundation occurs or the structure is subjected to external loads, the flexible connection units 7 formed in each closed cavity can undergo deformation to varying degrees. Due to the restraining effect of the lateral limiting structure 9, the engineering cement-based composite material 3 mainly undergoes tensile and shear deformation within the cavity, and gradually releases stress through multi-slit cracking, thereby avoiding the formation of concentrated cracks at the connection interface.

[0061] Even if the engineering cement-based composite material in the local cavity cracks or is damaged, the remaining closed cavities 6 can still bear the load, thus ensuring the stability of the overall connection structure.

[0062] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A 3D-printed modular component assembly and connection structure based on engineering cement-based composite materials, characterized in that, It includes a first module unit and a second module unit, wherein the first module unit and the second module unit are printed components with the same structure; The end of the first module unit includes alternating protrusions and recesses, the protrusions and recesses are of the same height, and the sidewalls of adjacent protrusions form a lateral limiting structure. Each protrusion has a notch at its end. When the first module unit and the second module unit are spliced ​​together, the protrusion of one module unit is embedded in the recess of the other module unit. The notch forms multiple closed cavities extending along the connection direction on the docking interface. The enclosed cavity is filled with an engineering cement-based composite material.

2. The 3D-printed modular component assembly and connection structure based on engineering cement-based composite materials according to claim 1, characterized in that, The shape of the enclosed cavity is rectangular, trapezoidal, semi-circular, or stepped.

3. The 3D-printed modular component assembly and connection structure based on engineering cement-based composite materials according to claim 2, characterized in that, The engineering cement-based composite material is prepared using cement, fly ash, fine sand and PVA fiber, with a fiber volume fraction of 1.5% to 2.0%.

4. The 3D-printed modular component assembly and connection structure based on engineering cement-based composite materials according to claim 3, characterized in that, The ultimate tensile strain of the engineering cement-based composite material is 6% to 10%, and multiple dispersed microcracks are formed when it is under tension.

5. A construction method for an assembly and connection structure of 3D-printed modular components based on engineering cement-based composite materials as described in any one of claims 1-4, characterized in that, Includes the following steps: S1, the first module unit and the second module unit are prepared by 3D printing, with a printing layer height of 8-12 mm and a printing strip width of 24-36 mm; the end of each module unit is composed of alternating protrusions and recesses; S2, the first module unit and the second module unit are misaligned and aligned and then assembled so that the protrusion of the first module unit is precisely embedded in the recess of the second module unit, forming multiple closed cavities on the mating surface. S3. After assembly, inject engineering cement-based composite material into the closed cavity. During the pouring process, use vibration or self-leveling to ensure that the material fully fills the closed cavity. S4, after pouring, should be naturally cured or covered for curing.

6. The method for preparing a 3D-printed modular component assembly and connection structure based on engineering cement-based composite materials according to claim 5, characterized in that, The printed components are made of 3D printed concrete.

7. The method for preparing a 3D-printed modular component assembly and connection structure based on engineering cement-based composite materials according to claim 5, characterized in that, In step S2, the height of the protrusion is 150~250 mm, the width is 300 mm, and the distance between adjacent protrusions is 300 mm.

8. The method for preparing a 3D-printed modular component assembly and connection structure based on engineering cement-based composite materials according to claim 5, characterized in that, In step S2, the height of the enclosed cavity is 80-100mm and the width is 120-150mm.

9. The method for preparing a 3D-printed modular component assembly and connection structure based on engineering cement-based composite materials according to claim 5, characterized in that, In step S4, the curing time is 3 to 7 days to harden the engineering cement-based composite material.

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