Concrete 3D printing device and method based on magnetorheological response

Abstract

The embodiment of the invention relates to the technical field of concrete 3D printing, and provides a concrete 3D printing device and method based on magnetorheological response, and the device comprises a printer main body, a first magnetic field module and a second magnetic field module; the first magnetic field module is arranged on the outer side of a printing head of the printer body and used for applying an annular magnetic field to the printing head so as to guide the extrusion direction of steel fibers in a concrete material to be directionally arranged before the concrete material is extruded to a component. The second magnetic field module is arranged below the component and used for applying an adjustable magnetic field to the printed concrete strip so as to guide steel fibers in the concrete strip to be sequentially connected with the interlayer interface of the component in a bridging mode, and the direction of the magnetic field generated by the first magnetic field module is matched with the direction of the magnetic field generated by the second magnetic field module. By means of the device provided by the embodiment of the specification, the printability of 3D printing concrete and the interlayer bonding performance can be improved.

Description

Technical Field

[0001] This specification relates to the field of concrete 3D printing technology, and in particular to a concrete 3D printing apparatus and method based on magnetorheological response. Background Technology

[0002] 3D printing of concrete based on extrusion technology is a groundbreaking technology in the field of construction engineering, which has developed rapidly in recent years. This technology achieves automated and rapid construction of complex geometries by layer-by-layer concrete deposition, offering extremely high design flexibility and construction efficiency. Compared with traditional formwork casting methods, 3D printed concrete technology eliminates the need for formwork, significantly reducing labor costs and material waste, aligning with the low-carbon, sustainable, and intelligent development trends of the construction industry. To improve the ductility and tensile strength of printed components, ductile fibers are typically added to the mix proportions. Steel fibers, due to their excellent tensile strength and good compatibility with cementitious materials, are widely used in research and practice. However, the addition of steel fibers reduces the workability and printability of the concrete. Especially during extrusion, the slender steel fibers are prone to entanglement, leading to nozzle clogging and print strip breakage. In other words, the weak interlayer and inter-strip bonding properties of the printed components are not effectively improved by the incorporation of steel fibers. Conventional improvement methods include optimizing the mix proportions (e.g., using water-reducing agents or viscosity modifiers) or adjusting printing parameters (e.g., modifying printing speed and nozzle height). However, the above methods rely on a large number of experiments, resulting in high trial-and-error costs and a lack of versatility. In addition, once concrete is mixed, the time-varying relationship of its printing properties is determined, lacking the ability to actively control unexpected situations during the printing process (such as reduced workability due to delays) and the rheological properties of concrete. Summary of the Invention

[0003] In view of the above-mentioned problems in the prior art, the purpose of the embodiments of this specification is to provide a concrete 3D printing device and method based on magnetorheological response, so as to improve the printability of 3D printed concrete and the bonding performance between layers.

[0004] To solve the above-mentioned technical problems, the specific technical solutions of the embodiments in this specification are as follows:

[0005] On the one hand, the embodiments of this specification provide a concrete 3D printing device based on magnetorheological response, the device including: a printer body, a first magnetic field module and a second magnetic field module;

[0006] The first magnetic field module is disposed on the outside of the print head of the printer body, and is used to apply a ring magnetic field at the print head to guide the steel fibers in the concrete material to align in the extrusion direction before the concrete material is extruded into the component.

[0007] The second magnetic field module is disposed below the component and is used to apply an adjustable magnetic field to the printed concrete strip to guide the steel fibers therein to sequentially bridge the interlayer interface of the component. The direction of the magnetic field generated by the first magnetic field module matches the direction of the magnetic field generated by the second magnetic field module.

[0008] Furthermore, the first magnetic field module includes a ring magnet and a first fixing device; the ring magnet is sleeved on the outside of the print head, and the first fixing device is fixedly connected to the print head to fix the ring magnet on the print head; the magnetic field generated by the ring magnet is in the same direction as the extrusion direction of the print head to guide the steel fibers to oriented along the extrusion direction.

[0009] Furthermore, the second magnetic field module includes a block magnet, an XY plane moving platform, a tiltable / liftable platform, and a second fixing device;

[0010] The block magnet is mounted on the tiltable / liftable platform via the second fixing device to apply an adjustable magnetic field to the printed concrete strips, so as to guide the steel fibers therein to sequentially bridge the interlayer interfaces of the component.

[0011] The upper part of the tiltable / liftable platform is connected to the block magnet, which is used to support the block magnet and adjust its height and tilt angle;

[0012] The upper part of the XY plane moving platform is connected to the tiltable / liftable platform, which is used to drive the tiltable / liftable platform to move synchronously along the printing path.

[0013] Furthermore, the device also includes a deformation monitoring module, which is installed above and to the side of the printer body to monitor the width and height data of the printed concrete strips on the printing platform in real time.

[0014] Furthermore, the deformation monitoring module includes at least two laser displacement sensors and a third fixing device; one laser displacement sensor is mounted on the side of the printing platform via the third fixing device to monitor the width data of the concrete strip; the other laser displacement sensor is mounted above the printing platform via the third fixing device to monitor the height data of the concrete strip.

[0015] Furthermore, the device also includes a control system, which is electrically connected to the first magnetic field module, the second magnetic field module, and the deformation monitoring module, respectively, for receiving monitoring data from the deformation monitoring module and adjusting the first magnetic field module and the second magnetic field module in real time based on the monitoring data.

[0016] Furthermore, the control system includes a data acquisition unit, a data processing unit, and an execution control unit;

[0017] The data acquisition unit is used to receive the monitoring data transmitted by the laser displacement sensor;

[0018] The data processing unit is used to compare and analyze the monitoring data with preset standard parameters, determine whether there is a deviation, and generate control instructions based on the magnitude of the deviation.

[0019] The execution control unit is used to send the control command to the XY plane moving platform and the tiltable / liftable platform to adjust the position of the block magnet.

[0020] Furthermore, the method is applied to the concrete 3D printing apparatus described in any one of the above embodiments, comprising:

[0021] Obtain the pre-prepared concrete slurry;

[0022] The concrete slurry is injected into the concrete 3D printing device, and the concrete slurry is printed according to the preset target height and width;

[0023] Receive dimensional monitoring data of printed concrete strips;

[0024] The constructability of the printed concrete strip is assessed based on the dimensional monitoring data.

[0025] Determine whether to adjust the position of the block magnet based on the evaluation results;

[0026] Repeat the process of receiving the dimensional monitoring data of the printed concrete strips until printing is complete.

[0027] Furthermore, the dimensional monitoring data includes height monitoring data and width monitoring data; the assessment of the constructability of the printed concrete strip based on the dimensional monitoring data includes:

[0028] The aspect ratio stability coefficient and inter-story height difference are calculated based on the height monitoring data and width monitoring data.

[0029] The constructability of the printed concrete strip is evaluated based on the aspect ratio stability coefficient, the interlayer height difference, and their respective thresholds.

[0030] Furthermore, the position of the block magnet can be controlled using the following method:

[0031] The aspect ratio stability coefficient is calculated based on height monitoring data, width monitoring data, and preset target height and width.

[0032] The distance adjustment amount is calculated based on the aspect ratio stability coefficient.

[0033] If the aspect ratio stability coefficient is greater than the preset threshold, the tiltable / liftable platform is driven to descend according to the distance adjustment amount.

[0034] If the aspect ratio stability coefficient is less than a preset threshold, the tiltable / liftable platform is driven to rise according to the distance adjustment amount.

[0035] The tilt angle adjustment is calculated based on the actual magnetic field lines and preset angle generated by the block magnet at the printing platform; the preset angle is calculated based on the actual force applied to the printed object.

[0036] Adjust the tilt angle of the tiltable / liftable platform according to the tilt angle adjustment amount.

[0037] By adopting the above technical solution, the magnetorheological response-based concrete 3D printing device provided in this specification, through the setting of a first magnetic field module, utilizes a ring magnet to generate a magnetic field consistent with the extrusion direction, which can guide the steel fibers in the concrete to oriented along the extrusion direction, effectively avoiding the print head clogging problem caused by random distribution of steel fibers, and significantly improving the extrudability of 3D printed concrete; at the same time, the oriented steel fibers can better transmit stress, enhancing the strength of the printed component itself. Through the block magnet in the second magnetic field module, a controllable magnetic field can be applied to the printed concrete strips along the printing path, causing the steel fibers between layers to move and rotate in a preset manner to cope with different stress modes, creating fiber bridging between adjacent strips, greatly enhancing the bonding strength of the interlayer / strip interface, reducing the risk of cracking of the printed component, and improving the strength and durability of the overall structure. In addition, by moving or adjusting the block magnet of the platform magnetic field, a dynamically changing magnetic field can be generated, driving the fibers to produce rotational and translational response movements, locally disturbing and compacting the concrete matrix, thereby inducing beneficial micro-deformation in the concrete on a macroscopic level, and enhancing its constructability in real time. The above description is merely an overview of some embodiments of the technical solutions in this specification. In order to better understand the technical means of some embodiments of this specification and to implement them in accordance with the content of the specification, and to make the above and other objects, features and advantages of the embodiments of this specification more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments or prior art of this specification, the drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this specification. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 A schematic diagram of a concrete 3D printing apparatus based on magnetorheological response is shown in some embodiments of this specification.

[0040] Figure 2 A schematic diagram of the printing process of the first magnetic field module in some embodiments of this specification is shown;

[0041] Figure 3 This specification shows a schematic diagram of the structure of the second magnetic field module in some embodiments;

[0042] Figure 4 A schematic diagram of the printing process of the second magnetic field module in some embodiments of this specification is shown;

[0043] Figure 5 The diagram illustrates the steps of a concrete 3D printing method based on magnetorheological response in some embodiments of this specification.

[0044] Figure 6 The diagram illustrates the steps for evaluating the constructability of printed concrete strips in some embodiments of this specification;

[0045] Figure 7 This specification shows schematic diagrams illustrating the steps for adjusting the position of the block magnet in some embodiments;

[0046] Figure 8 The results of interlayer bond strength tests for printed components in some embodiments of this specification are shown;

[0047] Figure 9 A schematic diagram of the structure of a computer device according to an embodiment of this specification is shown.

[0048] Explanation of symbols in the attached drawings:

[0049] 1. Printer body;

[0050] 2. First magnetic field module;

[0051] 3. Second magnetic field module 3;

[0052] 4. Concrete material;

[0053] 5. Steel fiber;

[0054] 6. Direction of the magnetic field;

[0055] 7. Interlayer interface;

[0056] 201. Ring magnet;

[0057] 301. Block magnet;

[0058] 302. XY Plane Moving Platform;

[0059] 303. Tilting / lifting platform;

[0060] 902. Computer equipment;

[0061] 904, Processor;

[0062] 906. Memory;

[0063] 908. Drive mechanism;

[0064] 910. Input / Output Module;

[0065] 912. Input devices;

[0066] 914. Output devices;

[0067] 916. Presentation equipment;

[0068] 918. Graphical User Interface;

[0069] 920. Network interface;

[0070] 922. Communication link;

[0071] 924. Communication bus. Detailed Implementation

[0072] The technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this specification, and not all embodiments. Based on the embodiments in this specification, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this specification.

[0073] It should be noted that the terms "first," "second," etc., used in this specification, claims, and the foregoing drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, apparatus, product, or device that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices.

[0074] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties. Furthermore, the acquisition, storage, use, and processing of data in the technical solutions described in the embodiments of this application all comply with relevant regulations.

[0075] Steel fiber is a material with good ferromagnetic properties. Previous research has attempted to use magnetic fields to orient the arrangement of steel fibers in concrete components, thereby improving their tensile and flexural strength. Magnetic fields hold immense promise for applications in 3D-printed concrete. However, the magnetic field generating devices used in existing technologies are complex in design and manufacturing, and expensive. Their effectiveness depends on the incorporation of micron / nano-scale magnetic particles, and has not yet been validated in more common 3D-printed steel fiber reinforced concrete systems. Furthermore, it is difficult to achieve synergistic optimization of printing performance and material mechanical properties. Moreover, existing technologies only focus on the orientation of steel fibers in a single direction or region, lacking freely adjustable magnetic field strength and range of action. This fails to simultaneously improve the extrudability, constructability, and interlayer / strip bond strength of steel fiber reinforced concrete, thus preventing the integrated and active control of the printability and mechanical properties of 3D-printed steel fiber reinforced concrete.

[0076] To address the aforementioned problems, this specification provides an embodiment of a concrete 3D printing device based on magnetorheological response. Figure 1 This is a structural schematic diagram of a concrete 3D printing device based on magnetorheological response provided in the embodiments of this specification, as shown below. Figure 1As shown, the device includes a printer body 1, a first magnetic field module 2, and a second magnetic field module 3. The first magnetic field module 2 is disposed outside the printhead of the printer body 1 and is used to apply a ring magnetic field at the printhead to guide the steel fibers in the concrete material to align in the extrusion direction before the concrete material is extruded into the component. The second magnetic field module 3 is disposed below the component and is used to apply an adjustable magnetic field to the printed concrete strip to guide the steel fibers therein to sequentially bridge the interlayer interfaces of the component. The direction of the magnetic field generated by the first magnetic field module matches the direction of the magnetic field generated by the second magnetic field module.

[0077] When the printing material enters the print head for extrusion, the first magnetic field module 2 generates a magnetic field along the extrusion direction, initially guiding the steel fibers within the material to align along the flow direction, avoiding increased extrusion resistance caused by disordered fibers. Simultaneously, the second magnetic field module 3 moves synchronously with the print head's trajectory. Through the synergistic effect of the first magnetic field module 2 and the second magnetic field module 3, the directional alignment of steel fibers in the unextruded material is improved, reducing energy loss caused by the "wall effect," minimizing the risk of nozzle clogging, and enhancing the material's extrudability. After the material is extruded and deposited as a printed strip, the second magnetic field module 3 generates vertical / oblique radial magnetic fields to reorient the steel fibers in the printed strip. This breaks the limitation of traditional fibers only being distributed along the strip's geometric boundaries, driving the fibers to rotate vertically or obliquely to meet different stress requirements. Vertical fibers can connect upper and lower printed strips, solving the problem of weak interlayer bonding in traditional 3D printing, while oblique fibers can connect adjacent printed strips, thereby improving the overall structural integrity. As the printhead continues to extrude new material along the path, the new fibers oriented by the magnetic field and the old fibers redirected by the second magnetic field module 3 form an orderly connection, avoiding the conflict between the fiber directions of the new strip and the old strip, and further strengthening the interlayer and interstrip interface bonding.

[0078] By adopting the above technical solution, the magnetorheological response-based concrete 3D printing device provided in this specification, through the setting of a first magnetic field module, utilizes a ring magnet to generate a magnetic field consistent with the extrusion direction, which can guide the steel fibers in the concrete to oriented along the extrusion direction, effectively avoiding the print head clogging problem caused by random distribution of steel fibers, and significantly improving the printability of 3D printed concrete; at the same time, the oriented steel fibers can better transmit stress, enhancing the strength of the printed component itself. Through the block magnet in the second magnetic field module, an adjustable magnetic field can be applied to the printed concrete strips along the printing path, causing the steel fibers between layers to attract each other and cross-anchor, greatly enhancing the bonding strength of the interlayer interface, reducing the risk of cracking of the printed component, and improving the strength and durability of the overall structure.

[0079] In the embodiments described in this specification, such as Figure 2As shown, the first magnetic field module 2 includes a ring magnet 201 and a first fixing device (not shown in the figure). The ring magnet 201 is sleeved on the outside of the print head. In some embodiments, the ring magnet 201 can be an electromagnet or a permanent magnet with a surface magnetic intensity of 0.1-0.3T. The first fixing device is fixedly connected to the print head and is used to fix the ring magnet 201 to the print head. The magnetic field generated by the ring magnet 201 is aligned with the extrusion direction of the print head. The vertical magnetic field formed inside the ring magnet 201 guides the steel fibers to align in the extrusion direction, optimizing the internal structural consistency of the printed component from the source.

[0080] In some embodiments of this specification, such as Figure 3 As shown, the printer body 1 also includes a printing platform with a printing plate on it for supporting the printed concrete strips. A second magnetic field module 3 is positioned between the printing plate and the printing platform. The second magnetic field module 3 includes a block magnet 301, an XY plane moving platform 302, a tiltable / liftable platform 303, and a second fixing device (not shown). The block magnet 301 is mounted on the tiltable / liftable platform 303 via the second fixing device and is used to apply an adjustable magnetic field to the printed concrete strips to guide the steel fibers within them to sequentially bridge the interlayer or interstrip interfaces of the structural members. Figure 4 As shown, the radial (vertical and oblique) magnetic field formed by the block magnet 301 causes the steel fibers to align vertically / obliquely during the stacking of the printing strips, thereby connecting the upper and lower or adjacent printing strips. In some embodiments, the block magnet 301 can be an electromagnet or a permanent magnet with a surface magnetic intensity of 0.1-0.3T.

[0081] The upper part of the XY plane moving platform 302 is connected to the tiltable / liftable platform 303, which is used to drive the tiltable / liftable platform 303 to move synchronously along the printing path of the print head, thereby driving the block magnet 301 to move synchronously along the printing path. Driven by the XY plane moving platform 302, the block magnet 301 can apply an adjustable magnetic field to the printed concrete strips and newly extruded concrete material along the printing path. This magnetic field will attract the steel fibers in the newly extruded concrete, allowing the steel fibers of the new layer and the old layer, and the new strip and the old strip to attract each other and cross-anchor, which greatly enhances the bonding performance between layers and strips, reduces the risk of cracking of printed components, and improves the strength and durability of the overall structure.

[0082] The upper part of the tiltable / liftable stage 303 is connected to the block magnet 301, which is used to support the block magnet 301 and adjust its height and tilt angle. Through the XY plane moving platform 302 and the tiltable / liftable stage 303, the block magnet 301 has four-way movable capability, which can be flexibly moved and adjusted according to printing needs, thereby adjusting the range and angle of the magnetic field and providing a suitable magnetic field environment for different areas of the printing platform, further enhancing the orientation effect of the steel fiber.

[0083] In some embodiments of this specification, the device further includes a deformation monitoring module. The deformation monitoring module is installed above and to the side of the printing platform to monitor the width and height data of the printed concrete strips on the printing platform in real time. It is understood that by monitoring the width and height data of the printed concrete strips in real time, it is possible to determine whether there are any abnormal problems such as uneven fiber orientation leading to accumulation or dispersion during the printing process, thereby allowing for timely adjustment of the printing process.

[0084] In some embodiments of this specification, the deformation monitoring module includes at least two laser displacement sensors and a third fixing device. One laser displacement sensor is mounted on the side of the printing platform via the third fixing device and is used to monitor the width data of the concrete strip. The other laser displacement sensor is mounted above the printing platform via the third fixing device and is used to monitor the height data of the concrete strip.

[0085] In some embodiments of this specification, the device further includes a control system. The control system is electrically connected to the first magnetic field module 2, the second magnetic field module 3, and the deformation monitoring module, respectively, and is used to receive monitoring data from the deformation monitoring module and to adjust the first magnetic field module 2 and the second magnetic field module 3 in real time based on the monitoring data. Combined with monitoring data from the displacement sensor, the control system can automatically adjust the distance between the second magnetic field module 3 and the printed bottom strip during the printing process, thereby dynamically matching the magnetic field strength with the molding requirements, achieving closed-loop adaptive control of the magnetic field and printing molding requirements. Compared with existing solutions relying on chemical additives, auxiliary cementitious materials, or other pretreatment methods, the embodiments of this specification can achieve active, real-time control of steel fiber orientation, printability, and interlayer / strip bonding performance, avoiding the decline in printing quality caused by material fluctuations, environmental changes, etc., and realizing intelligent control of the 3D printed concrete printing process. The embodiments of this specification can be applied to large-scale 3D printing of buildings, bridges, and prefabricated components requiring high interlayer strength.

[0086] In some embodiments of this specification, the control system includes a data acquisition unit, a data processing unit, and an execution control unit. The data acquisition unit receives monitoring data transmitted by the laser displacement sensor. The data processing unit compares and analyzes the monitoring data with preset standard parameters to determine if there is a deviation, and generates control commands based on the magnitude of the deviation. The execution control unit sends the control commands to the XY plane moving platform 302 and the tiltable / liftable platform 303 to adjust the position of the block magnet 301. For example, when the aspect ratio stability coefficient of the concrete strip is detected to be too small, the execution control unit can control the height of the tiltable / liftable platform 303 to reduce the distance between the block magnet 301 and the printing layer, enhance the magnetic field strength, improve the accumulation effect of the concrete material, and restore the aspect ratio of the strip to the standard range.

[0087] In some embodiments of this specification, the execution control unit controls the movement of the XY plane moving platform 302 and the tiltable / liftable platform 303 through an X / Y / Z three-axis controller, and can set the magnetic field strength and direction as needed to achieve the orientation of steel fibers at different positions of the printed strip.

[0088] Based on the above-described concrete 3D printing device based on magnetorheological response, this specification also provides a corresponding concrete 3D printing method based on magnetorheological response. Figure 5 This is a schematic diagram illustrating the steps of a concrete 3D printing method based on magnetorheological response provided in the embodiments of this specification. This specification provides the operational steps of the methods described in the embodiments or flowcharts, but based on conventional or non-inventive labor, more or fewer operational steps may be included. The order of steps listed in the embodiments is merely one possible execution order among many and does not represent the only possible execution order. In actual system or device products, the methods shown in the embodiments or drawings can be executed sequentially or in parallel. Specifically, as shown in the figures... Figure 5 As shown, the method may include:

[0089] S501: Obtain the pre-prepared concrete slurry;

[0090] S502: Inject the concrete slurry into the concrete 3D printing device, and print the concrete slurry according to the preset target height and width;

[0091] S503: Receive dimensional monitoring data of the printed concrete strips;

[0092] S504: Assess the constructability of the printed concrete strip based on the dimensional monitoring data;

[0093] S505: Determine whether to adjust the position of the block magnet based on the evaluation results;

[0094] S506: Repeat the step of receiving the dimensional monitoring data of the printed concrete strips until printing is complete.

[0095] Using the above technical solution, the concrete 3D printing method based on magnetorheological response provided in this specification prints according to a preset target height and width. During the printing process, it continuously receives dimensional monitoring data of the printed concrete strips, assesses the buildability of the strips based on the data, and determines whether to adjust the position of the block magnet. Finally, the dimensional monitoring steps are repeated until printing is complete. Its technical advantage lies in its ability to capture dimensional deviations of the printed strips in real time, accurately determine whether the position of the block magnet needs to be adjusted through buildability assessment to adapt to the influence of the magnetic field on the orientation of the steel fibers, and thus dynamically correct printing process deviations. This effectively ensures the dimensional accuracy of the concrete strips, reduces printing defects, improves the process stability and finished product quality of concrete 3D printing, and ensures that the printing process always conforms to the preset molding requirements, providing support for the reliable molding of concrete 3D printed components.

[0096] In this embodiment of the specification, the preparation process of concrete slurry in step S501 includes: selecting short, straight, copper-plated low-carbon steel fibers with a volume fraction of 1%-2%, a length of 6-13 mm, a diameter of 0.2-0.3 mm, and a length-to-diameter ratio of approximately 30-45; the mass ratio of cement to fly ash, silica fume, and slag is 0.65:0.15:0.05:0.15; the mortar-to-cement ratio is 1:1; the maximum aggregate particle size is ≤ 2 mm; and the water-cement ratio is 0.32. A three-stage mixing method is used to prepare the 3D printing mortar. First, cement, auxiliary cementitious materials (fly ash, silica fume, and slag), aggregate, and powdered water-reducing agent are accurately weighed according to the mixing ratio and pre-mixed in a planetary mixer for at least 2 minutes. After ensuring uniform distribution of each component, a predetermined amount of water is added, and the mixture is stirred at low speed for 3 minutes. Subsequently, the mixer is paused for 30 seconds, and any unmixed mortar on the mixing blades and the mixing drum wall is scraped off. After pausing, mix again at low speed for 1.5 minutes, slowly pouring the steel fibers into the mixer during this time to prevent instantaneous clumping and ensure proper dispersion. Finally, switch the mixer to high speed and mix for 1.5 minutes. The total time for the entire wet mixing process should be kept under 7 minutes.

[0097] Step S502 involves injecting the prepared concrete slurry into the barrel of the printer body. A print head with an appropriate inner diameter is selected based on printing requirements, and the position of the laser displacement sensor in the deformation monitoring module is adjusted to ensure accurate monitoring of the width and height of the concrete strip. Then, the standard width, height parameters, and printing path parameters of the concrete strip are set in the control system. The printer body is started, and the concrete slurry in the barrel moves towards the print head under the action of the conveying mechanism. When the concrete slurry passes the annular magnet around the print head, the steel fibers in the concrete align along the extrusion direction under the magnetic field generated by the annular magnet. It is then extruded through the print head onto the printing platform, beginning the first layer printing. During printing, the control system controls the XY plane moving platform in the second magnetic field module to move the block magnet along the preset printing path. The magnetic field generated by the block magnet acts on the printed concrete strip and the newly extruded concrete material, causing the steel fibers between layers and strips to attract each other and cross-anchor, enhancing adhesion. Simultaneously, the tiltable / liftable platform adjusts the height and tilt angle of the printing platform in real time according to the instructions of the control system, ensuring that the magnetic field accurately acts on the interfaces between layers and strips.

[0098] In step S503, the laser displacement sensor in the deformation monitoring module monitors the dimensional data of the concrete strip in real time. In this embodiment, the dimensional monitoring data includes height monitoring data and width monitoring data. The height monitoring data is collected by a laser displacement sensor installed above the printing platform, and the width monitoring data is collected by a laser displacement sensor installed on the side of the printing platform.

[0099] Step S504: The deformation monitoring module transmits the dimensional monitoring data to the control system, which then evaluates the constructability of the printed concrete strip based on the dimensional monitoring data. In this embodiment, reference is made to... Figure 6 The constructability of the printed concrete strips is assessed based on dimensional monitoring data, specifically including the following steps:

[0100] S601: Calculate the aspect ratio stability coefficient and inter-story height difference based on the height monitoring data and width monitoring data;

[0101] S602: The constructability of the printed concrete strip is evaluated based on the aspect ratio stability coefficient, the interlayer height difference, and their respective threshold values.

[0102] It is understandable that in 3D printed concrete, constructability refers to the ability of materials to maintain their shape and not collapse when stacked between layers. The essence of constructability assessment is to determine the dimensional differences between the printed strips and the pre-set strips by quantifying the stability and consistency of dimensional monitoring data. In the embodiments of this specification, the following indicators are used for evaluation in conjunction with strip dimensional changes:

[0103] The aspect ratio stability coefficient is used to evaluate the overall shape stability of a single strip. For printed strips obtained using a fixed material and a fixed printing procedure, since height and width influence each other, the aspect ratio stability coefficient is calculated using monitoring data obtained from both. In the embodiments of this specification, the formula is used... Calculate the aspect ratio stability coefficient, where h r and h d These are the actual height and the preset height, respectively. r and w d These represent the actual width and the preset width, respectively. The closer the aspect ratio stability coefficient S is to 1, the more uniform the dimensions; S>1 indicates that the strip becomes "tall and thin," meaning the height is relatively large and the width is relatively small; S<1 indicates that the strip becomes "short and wide," meaning the height is relatively small and the width is relatively large.

[0104] The interlayer height difference is calculated when printing more than two layers, taking into account the height of the current layer and the height of the previous layer. This difference reflects whether the multi-layer stacking is flat. In the embodiments of this specification, the formula is used... Calculate the height difference between floors, where This represents the average height of the current layer. This indicates the average height of the previous layer. A larger difference in height between layers indicates that the subsequent layers are more likely to have poor overlap.

[0105] After calculating the above index values, the constructability of the strip is evaluated based on the index values ​​and corresponding thresholds. The thresholds can be determined through preliminary experimental calibration, combined with the material properties of 3D printed concrete, printing parameters, and functional requirements of the components. When the aspect ratio stability coefficient is greater than or less than the preset threshold, or the interlayer height difference is greater than the preset threshold, the constructability of the strip is poor, and the position of the block magnet needs to be adjusted based on monitoring data.

[0106] In the embodiments of this specification, refer to Figure 7 Step S505 adjusts the position of the block magnet in the following manner:

[0107] S701: The aspect ratio stability coefficient is calculated based on height monitoring data, width monitoring values, and preset target height and width.

[0108] S702: The distance adjustment amount is calculated based on the aspect ratio stability coefficient;

[0109] S703: If the aspect ratio stability coefficient is greater than the preset threshold, the tiltable / liftable platform is driven to descend according to the distance adjustment amount.

[0110] S704: If the aspect ratio stability coefficient is less than a preset threshold, the tiltable / liftable platform is driven to rise according to the distance adjustment amount.

[0111] S705: Calculate the tilt angle adjustment amount based on the actual magnetic field line direction and preset angle generated by the block magnet at the printing platform; the preset angle is calculated based on the actual force applied to the printed object.

[0112] S706: Adjust the tilt angle of the tiltable / liftable platform according to the tilt angle adjustment amount.

[0113] It is understandable that the distance adjustment refers to the change in height of the tilting / lifting platform, which alters the vertical distance between the block magnet and the printing strip, thereby changing the magnetic field strength; that is, a smaller distance strengthens the magnetic field, and a larger distance weakens the magnetic field, ultimately correcting shape deviations. The tilt angle adjustment refers to the change in the rotation angle of the tilting / lifting platform, which changes the tilt direction of the block magnet, thereby changing the direction of the magnetic field lines on the strip, ultimately correcting fiber movement behavior. In the embodiments of this specification, the distance adjustment is calculated using the aspect ratio stability coefficient, and the tilt angle adjustment is calculated using the direction of force.

[0114] When the aspect ratio stability coefficient is greater than the preset threshold, it indicates that the actual aspect ratio is greater than the target aspect ratio. The reason why the strip is too "tall and thin" is that the distance between the block magnet and the strip is too close, resulting in an excessively strong magnetic field. This causes the concrete slurry to be attracted by the strong magnetic field and excessively aggregate. Therefore, it is necessary to increase the distance between the block magnet and the strip, that is, drive the tiltable / liftable platform to descend. At this time, the block magnet moves down accordingly, the distance between the block magnet and the strip increases, the magnetic field strength weakens, the force of the slurry being attracted by the magnetic field decreases, and the aspect ratio of the subsequently printed strip will decrease, gradually approaching the target aspect ratio. Conversely, when the aspect ratio stability coefficient is less than the preset threshold, it indicates that the actual aspect ratio is less than the target aspect ratio. The strip is too "short and wide" because the distance between the block magnet and the strip is too far, resulting in a weak magnetic field. This causes the concrete slurry to be insufficiently affected by the strong magnetic field. Therefore, it is necessary to reduce the distance between the block magnet and the strip, that is, drive the tiltable / liftable platform to rise. At this time, the block magnet moves upward, the distance between the block magnet and the strip decreases, the magnetic field strength increases, the force of the slurry being attracted by the magnetic field increases, and the height of the subsequently printed strip will increase, gradually approaching the target height.

[0115] By dynamically adjusting the tilt angle of the bottom magnetic field, active and precise control of the spatial orientation of steel fibers is achieved, thereby customizing the enhancement of component performance for different stress conditions. When the structure mainly bears interlaminar shear, the tilt angle of the magnet is not changed, guiding the fibers through the interlaminar interface to provide bridging and shear resistance. When facing the risk of interlaminar tension or delamination, the tilt angle is calculated to generate an oblique magnetic field in the magnet, efficiently converting tensile stress into tensile stress in the fibers. This strategy upgrades fiber reinforcement from the traditional "uniform distribution" to "on-demand orientation," fundamentally optimizing the anisotropy of the material.

[0116] To better illustrate the effectiveness of the above-mentioned scheme in improving extrudability and interlayer bonding in concrete 3D printing, this specification verifies it with a specific embodiment. C50 grade 3D printing steel fiber mortar was prepared using steel fibers with a length of 13 mm and a diameter of 0.3 mm at a volume fraction of 2%. The prepared steel fiber cement mortar was poured into a 3D printer to print cuboid specimens of 300 mm, 125 mm, and 100 mm. The horizontal printing speed was 4800 mm / min, and the layer width and height were 25 mm and 10 mm, respectively. After printing, the specimens were covered with a protective film and cut after 24 hours. The resulting specimens (40 mm × 40 mm × 40 mm cubes) were placed in a laboratory environment with a temperature of 20 degrees Celsius and a humidity of 50% for curing. Interlayer bond strength tests were conducted after 28 days. The cube specimens were divided into two categories based on whether they were affected by the magnetic field of the second magnetic field module: those affected by the magnetic field and those not affected by the magnetic field. The test results are shown in […]. Figure 8 .

[0117] Figure 8 Data shows that, under the influence of the second magnetic field module, the interlayer and interstrip interface bond strength of the cubic sample affected by the magnetic field are higher than those of the corresponding unaffected sample, with the interlayer and interstrip interface bond strengths increasing by 31% and 11%, respectively. It is evident that the technical solution of the embodiments in this specification significantly improves the interfacial bonding performance of 3D printing steel fiber mortar and enhances the overall integrity of the printed component.

[0118] Reference Figure 9As shown, based on the above-described method for 3D printing concrete using magnetorheological response, one embodiment of this specification also provides a computer device 902, wherein the above-described method operates on the computer device 902. The computer device 902 may include one or more processors 904, such as one or more central processing units (CPUs), each of which can implement one or more hardware threads. The computer device 902 may also include any memory 906 for storing any kind of information, such as code, settings, data, etc. Non-limitingly, for example, the memory 906 may include any type of RAM, any type of ROM, flash memory, hard disk, optical disk, etc. More generally, any memory can use any technology to store information. Further, any memory can provide volatile or non-volatile retention of information. Further, any memory can represent a fixed or removable component of the computer device 902. In one case, when the processor 904 executes associated instructions stored in any memory or combination of memories, the computer device 902 can perform any operation of the associated instructions. The computer device 902 also includes one or more drive mechanisms 908 for interacting with any memory, such as a hard disk drive mechanism, an optical disk drive mechanism, etc.

[0119] Computer device 902 may also include an input / output module 910 (I / O) for receiving various inputs (via input device 912) and providing various outputs (via output device 914). A specific output mechanism may include a presentation device 916 and an associated graphical user interface (GUI) 918. In other embodiments, the input / output module 910 (I / O), input device 912, and output device 914 may be omitted, and the device may function solely as a computer device within a network. Computer device 902 may also include one or more network interfaces 920 for exchanging data with other devices via one or more communication links 922. One or more communication buses 924 couple the components described above together.

[0120] Communication link 922 can be implemented in any way, such as via a local area network, a wide area network (e.g., the Internet), a point-to-point connection, or any combination thereof. Communication link 922 may include any combination of hardwired links, wireless links, routers, gateway functions, name servers, etc., governed by any protocol or combination of protocols.

[0121] Corresponding to, for example Figures 5 to 7 In addition to the method shown, embodiments of this specification also provide a computer-readable storage medium storing a computer program that, when executed by a processor, performs the steps of the above-described method.

[0122] This specification also provides computer-readable instructions, wherein when a processor executes the instructions, the program therein causes the processor to perform the following... Figures 5 to 7 The method shown.

[0123] This specification also provides a computer program product, including at least one instruction or at least one program segment, wherein the at least one instruction or the at least one program segment is loaded and executed by a processor to achieve the following: Figures 5 to 7 The method shown.

[0124] It should be understood that in the various embodiments of this specification, the sequence number of each process does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this specification.

[0125] It should also be understood that, in the embodiments of this specification, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this specification generally indicates that the preceding and following related objects have an "or" relationship.

[0126] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed in this specification can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of each example have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this specification.

[0127] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0128] In the several embodiments provided in this specification, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the couplings or direct couplings or communication connections shown or discussed may be indirect couplings or communication connections through some interfaces, devices, or units, or they may be electrical, mechanical, or other forms of connection.

[0129] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of the embodiments described in this specification, depending on actual needs.

[0130] Furthermore, the functional units in the various embodiments of this specification can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0131] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this specification, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this specification. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0132] This specification uses specific embodiments to illustrate the principles and implementation methods of this specification. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this specification. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this specification. Therefore, the content of this specification should not be construed as a limitation of this specification.

Claims

1. A magnetorheological response based concrete 3D printing device, characterized by, The device comprises a printer body, a first magnetic field module and a second magnetic field module; The first magnetic field module is arranged outside the print head of the printer body, and is used to apply a ring-shaped magnetic field at the print head to guide the steel fibers in the concrete material to be arranged in the extrusion direction before the concrete material is extruded into the component; The second magnetic field module is arranged below the component, and is used to apply an adjustable magnetic field to the printed concrete strip to guide the steel fibers therein to sequentially bridge the interlayer interfaces of the component, and the magnetic field direction generated by the first magnetic field module matches the magnetic field direction generated by the second magnetic field module.

2. The apparatus of claim 1, wherein, The first magnetic field module comprises a ring-shaped magnet and a first fixing device; the ring-shaped magnet is sleeved outside the print head, and the first fixing device is fixedly connected with the print head to fix the ring-shaped magnet on the print head; the magnetic field direction generated by the ring-shaped magnet is consistent with the extrusion direction of the print head to guide the steel fibers to be arranged in the extrusion direction.

3. The apparatus of claim 1, wherein, The second magnetic field module comprises a block-shaped magnet, an XY plane moving platform, an inclinable / liftable object table and a second fixing device; The block-shaped magnet is installed on the inclinable / liftable object table through the second fixing device, and is used to apply an adjustable magnetic field to the printed concrete strip to guide the steel fibers therein to sequentially bridge the interlayer interfaces of the component; The upper part of the inclinable / liftable object table is connected with the block-shaped magnet to carry the block-shaped magnet and adjust the height and inclination angle thereof; The upper part of the XY plane moving platform is connected with the inclinable / liftable object table to drive the inclinable / liftable object table to synchronously move along the printing path.

4. The apparatus of claim 3, wherein, The device further comprises a deformation monitoring module which is installed above and on the side of the printer body, and is used to monitor the width data and height data of the printed concrete strip on the printing platform in real time.

5. The apparatus of claim 4, wherein, The deformation monitoring module comprises at least two laser displacement sensors and a third fixing device; one laser displacement sensor is installed on the side of the printing platform through the third fixing device to monitor the width data of the concrete strip; and the other laser displacement sensor is installed above the printing platform through the third fixing device to monitor the height data of the concrete strip.

6. The apparatus of claim 5, wherein, The device further comprises a control system which is electrically connected with the first magnetic field module, the second magnetic field module and the deformation monitoring module respectively, and is used to receive the monitoring data of the deformation monitoring module and to real-time regulate and control the first magnetic field module and the second magnetic field module according to the monitoring data.

7. The apparatus of claim 6, wherein, The control system comprises a data acquisition unit, a data processing unit and an execution control unit; The data acquisition unit is used to receive the monitoring data transmitted by the laser displacement sensor; The data processing unit is used to compare and analyze the monitoring data with the preset standard parameters, to judge whether there is a deviation, and to generate a regulation instruction according to the deviation size; The execution control unit is used to send the regulation instruction to the XY plane moving platform and the inclinable / liftable object table to adjust the position of the block-shaped magnet.

8. A method for 3D printing of concrete based on magneto-rheological response, characterized by, The method is applied to the concrete 3D printing device of any one of claims 1-7, comprising: acquiring a pre-prepared concrete slurry; injecting the concrete slurry into the concrete 3D printing device and printing the concrete slurry according to a preset target height and width; receiving size monitoring data of the printed concrete strip; evaluating the constructability of the printed concrete strip according to the size monitoring data; judging whether to regulate the position of the block magnet according to the evaluation result; repeating the step of receiving size monitoring data of the printed concrete strip until printing is completed.

9. The method of claim 8, wherein, The size monitoring data includes height monitoring data and width monitoring data; the evaluation of the constructability of the printed concrete strip according to the size monitoring data comprises: calculating a height-width ratio stability coefficient and an interlayer height difference according to the height monitoring data and width monitoring data; evaluating the constructability of the printed concrete strip according to the height-width ratio stability coefficient and the interlayer height difference and their respective threshold values.

10. The method of claim 9, wherein, The position of the block magnet is regulated in the following way: calculating a height-width ratio stability coefficient according to the height monitoring data, width monitoring data, preset target height, and width; calculating a distance adjustment amount according to the height-width ratio stability coefficient; if the height-width ratio stability coefficient is greater than a preset threshold value, driving the tiltable / liftable object table to descend according to the distance adjustment amount; if the height-width ratio stability coefficient is less than a preset threshold value, driving the tiltable / liftable object table to ascend according to the distance adjustment amount; calculating a tilting angle adjustment amount according to the actual magnetic field line direction generated by the block magnet at the printing platform and a preset angle; the preset angle is calculated according to the actual stress mode of the printed object; adjusting the tilting angle of the tiltable / liftable object table according to the tilting angle adjustment amount.

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