A 3D printing concrete interlayer bonding strength inversion method, device, equipment and storage medium

Abstract

This invention relates to the field of performance testing and prediction technology for building materials, and provides a method, apparatus, equipment, and storage medium for inverting the interlayer bond strength of 3D printed concrete. It determines the moisture evaporation index by weighing and monitoring accompanying concrete specimens, and determines the actual interlayer interval time by analyzing the printing path timing information of the target component. Based on the synchronous inversion technology of accompanying concrete specimens, the moisture evaporation index is calculated in real time using the mass change of accompanying specimens under the same environmental field, realizing the online quantitative acquisition of the core internal factors affecting interlayer strength. By calculating the dynamic relationship between the interlayer printing time interval and the environmental evaporation in real time, the online prediction of the interlayer bond strength inside the 3D printed concrete part is achieved, solving the problem of the inability to quantify hidden defects in real time. By comparing the estimated interlayer bond strength value with the pre-stored strength threshold, and outputting corresponding graded early warning signals based on the comparison results, proactive feedback early warning is realized.

Description

Technical Field

[0001] This invention relates to the field of performance testing and prediction technology for building materials, and in particular to a method, apparatus, equipment, and storage medium for inverting the interlayer bond strength of 3D printed concrete. Background Technology

[0002] With the rapid development of industrialized construction, concrete 3D printing technology, as an additive manufacturing technology that requires no molds and has a high degree of automation, is gradually changing the traditional production methods of the construction industry. It constructs three-dimensional entities by stacking materials layer by layer, showing great application potential in fields such as the construction of irregular-shaped buildings and disaster relief.

[0003] However, the layer-by-layer stacking process makes the interlayer interfaces a weak point in structural performance. Existing quality monitoring technologies mostly employ machine vision, laser scanning, or digital twin methods, comparing the printed object with the design model, mainly focusing on detecting geometric errors such as printing layer height and width deviations and collapse deformation, to ensure that the dimensional accuracy of the component meets the design requirements.

[0004] However, simple geometric inspection cannot detect the interlayer bond strength that determines structural safety. In actual printing, the dynamically changing interlayer interval and environmental factors lead to varying degrees of moisture accumulation and evaporation at the interface, resulting in a nonlinear decay of interlayer bond performance. Because current technology lacks a quantitative model that correlates the "spatiotemporal-evaporation" process with "mechanical strength," the system struggles to identify these hidden internal strength defects during printing, making real-time early warning and closed-loop control based on performance indicators impossible.

[0005] Therefore, it is necessary to propose a method, apparatus, equipment, and storage medium for inverting the interlayer bond strength of 3D printed concrete to solve or at least alleviate the above-mentioned defects. Summary of the Invention

[0006] The main objective of this invention is to provide a method, apparatus, equipment, and storage medium for inverting the interlayer bond strength of 3D printed concrete, in order to solve the technical problem that existing technologies, which rely on simple geometric detection, cannot perform online inversion of the interlayer bond strength that determines structural safety during the 3D printing process of concrete.

[0007] To achieve the above objectives, this invention provides a method for inverting the interlayer bond strength of 3D printed concrete, comprising the following steps:

[0008] S1, In the same environmental field that is physically separated from the target component, the concrete accompanying specimen is printed simultaneously using the same 3D printing equipment;

[0009] S2, acquire the weighing monitoring data of the concrete accompanying specimen, and determine the moisture evaporation index to reflect the degree of moisture evaporation of the concrete accompanying specimen based on the weighing monitoring data; and acquire the printing path timing information of the target component, and determine the actual interlayer interval time to reflect the process state between the current printing layer and the printed layer of the target component based on the printing path timing information.

[0010] S3, input the moisture evaporation index and the actual interlayer interval time into the pre-established strength inversion model, calculate the interlayer bond strength index of the target component at the current printing position in real time, and determine the estimated value of the interlayer bond strength with physical meaning based on the interlayer bond strength index; wherein, the strength inversion model includes the mapping relationship between the moisture evaporation index, the actual interlayer interval time and the interlayer bond strength index;

[0011] S4. The estimated value of interlayer bond strength is compared with the pre-stored strength threshold, and the corresponding graded early warning signal is output according to the comparison result.

[0012] Preferably, the intensity inversion model in step S3 is obtained through the following steps:

[0013] S31, based on the same concrete material mix ratio as the target component, perform multiple sets of calibration printing tests; wherein, each set of calibration printing tests sets a preset interlayer interval time and a set of environmental parameter combinations, and simultaneously prints calibration companion specimens in each set of calibration printing tests; the environmental parameter combinations include ambient temperature, ambient relative humidity and ambient wind speed.

[0014] S32, In each set of calibration printing tests, monitor the mass change of the calibration companion specimen to determine the moisture evaporation index of the calibration companion specimen, and record the corresponding preset interlayer interval time;

[0015] S33, after the calibration companion specimens of each group of calibration printing tests have been cured to the specified age, the interlaminar splitting tensile strength of the corresponding calibration companion specimens shall be tested respectively.

[0016] S34, using formula The actual value of the interlaminar bond strength index of the calibrated specimen was calculated. ;in, This is the measured value of interlaminar splitting tensile strength. The baseline interlaminar splitting tensile strength was obtained from a test without a printing time interval.

[0017] S35, using the preset interlayer interval time and the moisture evaporation index obtained from multiple sets of calibration printing tests as input samples, and the corresponding actual value of the interlayer bond strength index. As the output sample, the intensity inversion model is obtained by fitting through multivariate nonlinear regression analysis.

[0018] Preferably, the step S2 of obtaining the weighing monitoring data of the concrete accompanying specimen and determining the moisture evaporation index to reflect the degree of moisture evaporation of the concrete accompanying specimen based on the weighing monitoring data includes the following steps:

[0019] Obtain the initial mass of the concrete specimen. And obtain the real-time mass of the concrete specimen obtained by continuous monitoring by the weighing sensor. ;

[0020] Using formula Calculate the cumulative evaporation water volume of the concrete specimen. ;

[0021] Based on the initial total water content of the concrete specimens. and the cumulative evaporation volume According to the formula The moisture evaporation index was obtained. .

[0022] Preferably, step S2, which involves obtaining the printing path timing information of the target component and determining the actual interlayer interval time reflecting the process status between the current printing layer and the already printed layers of the target component, includes the following steps:

[0023] The motion control command stream of the 3D printing equipment is read in real time to obtain the current moment when the target component arrives at the preset position point in the current printing layer;

[0024] Retrieve and obtain the printing completion time of the preset position point at the corresponding position in the previous printing layer from the database storing the historical printing time sequence of the target component;

[0025] The actual interlayer interval time at the preset location point is calculated based on the current time and the printing completion time.

[0026] Preferably, during the execution of step S2, the following environmental adaptive monitoring steps are also executed in parallel:

[0027] Real-time acquisition of current environmental parameters, and comparison of current environmental parameters with baseline environmental parameters recorded when the concrete specimen printing begins, to obtain the environmental parameter difference;

[0028] Determine whether the difference in the environmental parameters is greater than or equal to a preset environmental mutation threshold;

[0029] When the difference in the environmental parameters is greater than or equal to the preset environmental mutation threshold, the reference environmental parameters are updated to the current environmental parameters, and the 3D printing equipment is controlled to reprint a new concrete accompanying specimen as the subsequent monitoring object after completing the current printing task. At the same time, the updated reference environmental parameters and the new concrete accompanying specimen are used as the new reference and new object for data acquisition in step S2.

[0030] When the difference in environmental parameters is less than a preset environmental mutation threshold, the current concrete specimen and the baseline environmental parameters are maintained and used in step S2.

[0031] Preferably, step S4 includes the following steps:

[0032] The estimated interlayer bond strength is compared with a pre-stored strength safety threshold and a strength warning threshold; wherein the strength threshold includes a strength safety threshold and a strength warning threshold, and the strength safety threshold is greater than the strength warning threshold;

[0033] Based on the comparison results, when the estimated value of the interlayer bond strength is greater than or equal to the strength safety threshold, a first state signal is output, and the current printing parameters are maintained to continue working.

[0034] When the estimated interlayer bond strength is less than the strength safety threshold and greater than or equal to the strength warning threshold, a second state signal is output and a process adjustment instruction for shortening the subsequent interlayer interval time is generated.

[0035] When the estimated interlayer bond strength is less than the strength warning threshold, a third state signal is output, and an intervention command is generated to immediately enhance the current interlayer interface bond performance.

[0036] Preferably, the step S4 is followed by the following step:

[0037] Establish a mapping relationship between the estimated interlayer bond strength and the three-dimensional printing path coordinates of the target component;

[0038] Based on the mapping relationship, the different numerical ranges of the estimated interlayer bond strength are mapped to different preset colors, generating and updating in real time a mass distribution cloud map covering the structural shape represented by the 3D printing path coordinates, so as to visualize the spatial distribution of interlayer bond strength.

[0039] The present invention also provides a 3D printed concrete interlayer bond strength inversion device for performing the 3D printed concrete interlayer bond strength inversion method as described above, comprising:

[0040] The accompanying printing module is used to simultaneously print concrete accompanying specimens in the same environmental field that is physically separate from the target component using the same 3D printing equipment.

[0041] The data acquisition module is used to acquire the weighing monitoring data of the concrete accompanying specimen, and determine the moisture evaporation index based on the weighing monitoring data to reflect the degree of moisture evaporation of the concrete accompanying specimen; and to acquire the printing path timing information of the target component, and determine the actual interlayer interval time based on the printing path timing information to reflect the process state between the current printing layer and the printed layer of the target component.

[0042] The data inversion module is used to input the moisture evaporation index and the actual interlayer interval time into a pre-established strength inversion model, calculate the interlayer bond strength index of the target component at the current printing position in real time, and determine the estimated value of the interlayer bond strength with physical meaning based on the interlayer bond strength index; wherein, the strength inversion model includes the mapping relationship between the moisture evaporation index, the actual interlayer interval time and the interlayer bond strength index;

[0043] The early warning decision module is used to compare the estimated value of the interlayer bond strength with the pre-stored strength threshold, and output the corresponding graded early warning signal based on the comparison result.

[0044] The present invention also provides a 3D printed concrete interlayer bond strength inversion device, including a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, it implements the steps of the 3D printed concrete interlayer bond strength inversion method as described above.

[0045] The present invention also provides a storage medium storing a computer program, which, when executed by a processor, implements the steps of the above-described method for inverting the interlayer bond strength of 3D printed concrete.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] This invention provides a method, apparatus, equipment, and storage medium for inverting the interlayer bond strength of 3D printed concrete. This application determines the moisture evaporation index by weighing and monitoring accompanying concrete specimens, and determines the actual interlayer interval time by analyzing the printing path timing information of the target component. Based on the synchronous inversion technology of accompanying concrete specimens, the moisture evaporation index is calculated in real time using the mass change of accompanying specimens under the same environmental field, realizing online quantification of the core internal factors affecting interlayer strength. By calculating the dynamic relationship between the interlayer printing time interval and the environmental evaporation rate in real time, the online inference of the interlayer bond strength inside the 3D printed concrete part is realized, solving the problem of the inability to quantify hidden defects in real time. By comparing the calculated estimated interlayer bond strength value with a pre-stored strength threshold, and outputting corresponding graded early warning signals based on the comparison results, proactive feedback early warning is achieved. Attached Figure Description

[0048] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0049] Figure 1 This is a schematic flowchart of one embodiment of the present invention;

[0050] Figure 2 This is a schematic diagram of a digital twin model in one embodiment of the present invention;

[0051] Figure 3 This is a quadratic fitting surface for interlayer interval time, moisture evaporation index, and splitting tensile strength index in one embodiment of the present invention;

[0052] Figure 4 This is a schematic diagram of the regression fitting of the concrete splitting tensile strength index based on the time-evaporation index in one embodiment of the present invention.

[0053] Figure 5 This is a schematic diagram of model verification in one embodiment of the present invention.

[0054] The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0055] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0056] 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 a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0057] In this invention, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Furthermore, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. If the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this invention.

[0058] Please refer to Figures 1 to 5 The present invention provides a method for inverting the interlayer bond strength of 3D printed concrete, comprising the following steps:

[0059] S1. In an identical environmental field, physically separated from the target component, a concrete accompanying specimen is simultaneously printed using the same 3D printing equipment. Before or simultaneously with the printing of the target component, in an adjacent location (i.e., an identical environmental field) physically separated from the target component but without obstruction and with consistent airflow, a simple concrete accompanying specimen is simultaneously printed using the same 3D printing equipment and the same batch of concrete material. The concrete accompanying specimen and the target component experience the same environmental conditions such as temperature, humidity, and wind speed.

[0060] S2, acquire the weighing monitoring data of the concrete accompanying specimen, and determine the moisture evaporation index to reflect the degree of moisture evaporation of the concrete accompanying specimen based on the weighing monitoring data; and acquire the printing path timing information of the target component, and determine the actual interlayer interval time to reflect the process state between the current printing layer and the printed layer of the target component based on the printing path timing information.

[0061] S3, the moisture evaporation index and the actual interlayer interval time are input into a pre-established strength inversion model to calculate the interlayer bond strength index of the target component at the current printing position in real time, and a physically meaningful estimated value of the interlayer bond strength is determined based on the interlayer bond strength index. The strength inversion model includes a mapping relationship between the moisture evaporation index, the actual interlayer interval time, and the interlayer bond strength index. This step inputs the real-time acquired moisture evaporation index and the actual interlayer interval time into the pre-established strength inversion model, outputs the interlayer bond strength index in real time, and then converts it into a physically meaningful (e.g., unit MPa) estimated value of the interlayer bond strength. This can be obtained by modifying the formula given in step S34 below. The dimensionless exponent was reduced to a physically meaningful estimated value for interlayer bond strength. And store it in the system database;

[0062] S4. The estimated value of interlayer bond strength is compared with the pre-stored strength threshold, and the corresponding graded early warning signal is output according to the comparison result.

[0063] This application determines the moisture evaporation index by weighing and monitoring the accompanying concrete specimens, and determines the actual interlayer interval time by analyzing the printing path timing information of the target component. Based on the synchronous inversion technology of the accompanying concrete specimens, the moisture evaporation index is calculated in real time using the mass change of the accompanying specimens under the same environmental field, realizing the online quantitative acquisition of the core internal factors affecting interlayer strength. By calculating the dynamic relationship between the interlayer printing time interval and the environmental evaporation in real time, the online extrapolation of the interlayer bond strength inside the 3D printed concrete part is realized, solving the problem that hidden defects cannot be quantified in real time. By comparing the calculated estimated value of interlayer bond strength with the pre-stored strength threshold, and outputting the corresponding graded early warning signal according to the comparison result, active feedback early warning is realized.

[0064] As a preferred embodiment, the intensity inversion model in step S3 is obtained through the following steps:

[0065] S31, based on the same concrete material mix ratio as the target component, perform multiple sets of calibration printing tests; wherein, each set of calibration printing tests sets a preset interlayer interval time and a set of environmental parameter combinations, and simultaneously prints calibration companion specimens in each set of calibration printing tests; the environmental parameter combinations include ambient temperature, ambient relative humidity and ambient wind speed.

[0066] To establish a strength inversion model, a series of systematic calibration printing tests were planned and executed in a controlled laboratory environment before formal construction, based on the proposed concrete mix proportions. The test design followed the univariate principle, simulating various conditions from continuous printing to long-interval shutdowns by setting a series of different preset interlayer intervals. Simultaneously, multiple combinations of environmental parameters were set, including ambient temperature (e.g., 15℃, 25℃, 35℃), relative humidity (e.g., 40%, 60%, 80%), and wind speed (e.g., 0m / s, 1m / s, 2m / s)—the three factors most significantly affecting moisture evaporation. This created multiple independent test conditions composed of different combinations of time and environmental conditions. For each condition consisting of preset interlayer intervals and environmental parameters, a calibration specimen was simultaneously printed using the same model of 3D printer as the one used in the future on-site construction. As an example, the calibration specimens can be designed as simple prisms (such as 100mm×100mm×50mm) or other shapes to facilitate subsequent quality monitoring.

[0067] S32, in each set of calibration printing tests, monitor the mass change of the calibration companion specimen to determine the moisture evaporation index of the calibration companion specimen, and record the corresponding preset interlayer interval time; in each set of tests, immediately place the printed calibration companion specimen on a high-precision weighing sensor (such as a high-precision electronic balance, accuracy 0.01g), continuously monitor and record its mass change over time until its mass is basically stable. According to the law of conservation of mass, the amount of mass reduction of the specimen is its moisture evaporation. Using this data, the moisture evaporation index corresponding to different exposure times under this condition can be calculated. At the same time, record the preset interlayer interval time for this set of tests.

[0068] S33. After the calibration companion specimens for each group of calibration printing tests have cured to the specified age, the measured interlaminar splitting tensile strength of the corresponding calibration companion specimens is tested. After completing the above process monitoring, all calibration companion specimens are placed in a curing chamber with the same temperature and relative humidity as the test environment, and cured for 28 days or other required ages. After the curing period, according to the same standard, the industry-standard splitting tensile test can be used to destructively test each calibration companion specimen to accurately measure its measured interlaminar splitting tensile strength. This strength value is the most direct and reliable mechanical index for evaluating interlaminar bond performance. Therefore, as a better example, the interlaminar splitting tensile strength is taken as the interlaminar bond strength.

[0069] S34, using formula The actual value of the interlaminar bond strength index of the calibrated specimen was calculated. ;in, This is the measured value of interlaminar splitting tensile strength. To obtain the baseline interlaminar splitting tensile strength from the no-printing-interval test, firstly, the arithmetic mean of the measured interlaminar splitting tensile strength values ​​obtained from several sets of tests with a preset interlaminar interval of 0 minutes (i.e., printing condition without printing time interval) can be calculated to obtain the baseline interlaminar splitting tensile strength. This refers to the optimal interlaminar bond strength achievable under ideal conditions with the current material mix proportions. Then, for each set of calibration printing tests, the actual value of the corresponding interlaminar bond strength index is calculated. .

[0070] S35, using the preset interlayer interval time and the moisture evaporation index obtained from multiple sets of calibration printing tests as input samples, and the corresponding actual value of the interlayer bond strength index. As the output sample, the intensity inversion model is obtained by fitting through multivariate nonlinear regression analysis.

[0071] Data from all calibration test groups were collected to form a dataset: each data point included independent variables (preset interlayer interval time and moisture evaporation index) and dependent variables (actual value of interlayer bond strength index). Based on our understanding of materials science (that strength decay may have a nonlinear relationship with time and moisture loss) and observations from scatter plots, we selected a mathematical model that can characterize complex nonlinear relationships for fitting.

[0072] In a preferred embodiment, a bivariate quadratic polynomial is used as the basic form of the model: ;in, This refers to the interlayer bond strength index. Interlayer interval, This is the evaporation index. These are the coefficients to be fitted. Mature multivariate nonlinear regression analysis algorithms (such as the least squares method) can be used to fit the experimental dataset, and the model coefficients that minimize the error between the model's predicted values ​​and the experimentally measured values ​​can be obtained. The fitting process can be implemented using general scientific computing tools such as MATLAB.

[0073] This application proposes a dual evaluation index of moisture evaporation index and interlayer bond strength index, which can identify the hidden danger of "cold seams" that appear intact but have failed internal bonding, thus making up for the blind spot of traditional visual inspection in the identification of hidden defects.

[0074] Preferably, the step S2 of obtaining the weighing monitoring data of the concrete accompanying specimen and determining the moisture evaporation index to reflect the degree of moisture evaporation of the concrete accompanying specimen based on the weighing monitoring data includes the following steps:

[0075] Obtain the initial mass of the concrete specimen. And obtain the real-time mass of the concrete specimen obtained by continuous monitoring by the weighing sensor. Immediately after the concrete specimen is printed, it is placed on the weighing platform of a high-precision weighing sensor (e.g., an electronic balance with an accuracy of 0.01 g). Once the reading stabilizes, the initial mass of the concrete specimen is recorded. The concrete specimens are continuously monitored using weighing sensors, and their real-time mass is collected and recorded at fixed time intervals (e.g., once per second). .

[0076] Using formula Calculate the cumulative evaporation water volume of the concrete specimen. ;

[0077] Based on the initial total water content of the concrete specimens. and the cumulative evaporation volume According to the formula The moisture evaporation index was obtained. .

[0078] To eliminate differences in absolute size or initial moisture content among various concrete specimens and to ensure the universality and comparability of monitoring indicators, this embodiment employs dimensionless processing. Based on the concrete mix proportions, the initial total moisture content of the concrete specimens is calculated and determined. For example, if the total water content and specimen volume in the mix proportion are known, the exact amount can be calculated. Alternatively, by weighing the total mass of all raw materials before printing and the initial mass of the specimen after printing. The result is obtained through correlation calculation. Then, based on the formula... Real-time calculation of water evaporation index This yields a state parameter characterizing the relative dryness of the material.

[0079] Preferably, step S2, which involves obtaining the printing path timing information of the target component and determining the actual interlayer interval time reflecting the process status between the current printing layer and the already printed layers of the target component, includes the following steps:

[0080] The motion control command stream of the 3D printing equipment is read in real time to obtain the current time when the target component arrives at a preset position point in the current printing layer; the real-time command stream of the motion control system of the 3D printing equipment is also read and parsed in real time. When the parsed motion control command stream indicates that the printing nozzle has arrived at a preset position point P(x, y, z) of the target component in the current printing layer, the high-precision clock source synchronized inside the 3D printing equipment is queried, and this time is recorded and stored as the current time of position point P. .

[0081] The system retrieves and obtains the printing completion time of the preset position point at the corresponding position in the previous printing layer from a database storing the historical printing time sequence of the target component. This database has previously recorded and stored the printing completion times of all critical path points for each layer in the same manner. When it is necessary to obtain the completion time of position point P at the corresponding position in the previous printing layer, the system quickly retrieves and reads the corresponding printing completion time from this time sequence database based on a unique three-dimensional coordinate index. .

[0082] Based on the current time and the printing completion time, the actual interlayer interval time at the preset position point is calculated. Using the formula... The actual interlayer interval time T at the current printing position is calculated in real time. This data corresponds precisely to each spatial coordinate point, thereby realizing the fine perception of interlayer process time parameters in three-dimensional space.

[0083] In a preferred embodiment, during step S2, the following environmental adaptive monitoring steps are also performed in parallel:

[0084] The system collects current environmental parameters in real time and compares them with baseline environmental parameters recorded when the concrete specimen printing begins to obtain the environmental parameter difference. Environmental sensors deployed within the printing area, including temperature, relative humidity, and an anemometer, collect current environmental parameters at preset time intervals. Simultaneously, a set of baseline environmental parameters recorded at the instant the concrete specimen printing begins, including initial temperature, initial relative humidity, and initial wind speed, are used. The difference between each corresponding parameter is calculated to obtain the environmental parameter difference.

[0085] The system determines whether the difference in the environmental parameters is greater than or equal to a preset environmental change threshold. To determine whether a drastic change has occurred in the environment sufficient to affect the evaporation pattern of concrete moisture, the system has a preset set of environmental change thresholds. These thresholds can be set according to actual needs. In a preferred example, the temperature change threshold is set to ±15℃, the relative humidity change threshold to ±15%, and the wind speed change threshold to ±2m / s.

[0086] When the difference in environmental parameters is greater than or equal to a preset environmental mutation threshold, the baseline environmental parameters are updated to the current environmental parameters. The 3D printing equipment, after completing the current printing task, is then controlled to reprint a new concrete specimen as a subsequent monitoring object. Simultaneously, the updated baseline environmental parameters and the new concrete specimen serve as the new baseline and object for data acquisition in step S2. For example, if any one of the environmental temperature, relative humidity, or wind speed exceeds the corresponding mutation threshold, the baseline environmental parameters are updated to the current environmental parameters. The updated baseline environmental parameters serve as the new baseline for data acquisition in step S2, and the new concrete specimen serves as the new object for data acquisition in step S2.

[0087] When the difference in environmental parameters is less than a preset environmental mutation threshold, the current concrete specimen and the baseline environmental parameters are maintained and used in step S2.

[0088] This embodiment uses environmental adaptive monitoring to automatically reset the baseline data of the accompanying specimens based on sudden changes in temperature, humidity and wind speed. This ensures that the prediction model can dynamically adapt to the micro-environmental fluctuations at the construction site, guaranteeing the prediction accuracy during long-term printing and thus improving the long-term reliability and accuracy of the strength inversion results.

[0089] In a preferred embodiment, step S4 includes the following steps:

[0090] The estimated interlayer bond strength is compared with a pre-stored strength safety threshold and strength warning threshold; wherein the strength threshold includes a strength safety threshold and a strength warning threshold, and the strength safety threshold is greater than the strength warning threshold; the strength safety threshold and the strength warning threshold can be determined based on the design safety requirements of the target structure, the standard strength of the material, and a large amount of historical test data.

[0091] Based on the comparison results, when the estimated value of the interlayer bond strength is greater than or equal to the strength safety threshold, a first state signal is output, and the current printing parameters are maintained to continue working.

[0092] When the estimated interlayer bond strength is less than the strength safety threshold but greater than or equal to the strength warning threshold, a second state signal is output, and a process adjustment instruction to shorten the subsequent interlayer interval time is generated. This situation indicates that the current interlayer bond performance has shown a deterioration trend. Although there is no immediate danger, it is below the ideal safety margin, and there is a risk of it developing into a defect. A second state signal characterizing the risk warning (such as a flashing yellow warning and an alarm sound) is output immediately. The process adjustment instruction may be to increase the printhead movement speed or appropriately reduce the single-layer printing height in subsequent path planning, with the aim of shortening the interlayer interval time between the subsequent layer to be printed and the already printed layer, thereby reducing the exposure time of the lower layer and improving bonding conditions.

[0093] When the estimated interlayer bond strength is less than the strength warning threshold, a third state signal is output, and an intervention command is generated to immediately enhance the current interlayer interface bond performance.

[0094] This situation indicates that the current interlayer adhesion has deteriorated to an unacceptable level, and without intervention, it is highly likely to lead to fatal defects such as cold seams. A third-state signal indicating non-compliance / emergency (such as a persistent red alarm and beeping) is output, triggering the highest level of intervention. For example, this could involve generating and sending a pause print command to prevent further material buildup on the poor interface, which could cause even greater problems. Immediately afterward, the already printed, insufficiently strong interlayer interface can be treated with a spray coating to instantly enhance its interface properties by adding adhesive material and moisture. Printing can only resume after the remedial measures are completed and confirmed.

[0095] In another preferred embodiment, the step S4 is followed by the following steps:

[0096] A mapping relationship is established between the estimated interlayer bond strength and the three-dimensional printing path coordinates of the target component. Specifically, after calculating the estimated interlayer bond strength, the corresponding three-dimensional printing path coordinates obtained from the printer motion control system are recorded synchronously. Each estimated interlayer bond strength is associated and bound one-to-one with its corresponding three-dimensional printing path coordinates to form a data pair. These data pairs are stored in a spatial database in real time, and the mapping relationship between the two is established by using the three-dimensional coordinates as a unique index.

[0097] Based on the mapping relationship, the different numerical ranges of the estimated interlayer bond strength are mapped to different preset colors, generating and updating in real time a mass distribution cloud map covering the structural shape represented by the 3D printing path coordinates, so as to visualize the spatial distribution of interlayer bond strength.

[0098] Based on the above mapping relationship, a color-coding rendering algorithm from computer graphics is used to convert the estimated interlayer bond strength values ​​in the database into a visual image in real time. A pre-defined color mapping rule is used: for example, estimated interlayer bond strength values ​​greater than 2.0 MPa are mapped to green; estimated interlayer bond strength values ​​between 1.6 MPa and 2.0 MPa are mapped to yellow; and estimated interlayer bond strength values ​​less than 1.6 MPa are mapped to red. By traversing all stored data points, the corresponding preset color is determined based on the range of estimated interlayer bond strength values. In the 3D rendering engine, this color is filled onto the surface or internal voxels of the virtual component represented by the corresponding coordinates. As printing progresses and new data is continuously generated, this cloud map is dynamically updated in near real-time. Figure 2 As shown, the real-time mapping of the entire life cycle of concrete 3D printing is completed in virtual space, and the interlayer strength is predicted by visualizing the interface color mapping.

[0099] This embodiment maps the predicted intensity into an intuitive three-dimensional chromatographic cloud map, and automatically executes intervention strategies such as optimizing parameters or spraying interface agents according to the warning level, realizing a leap from passive detection to proactive quality control.

[0100] To fully illustrate the technical solution of this application, the following specific embodiments are also provided to demonstrate the establishment and verification process of the intensity inversion model:

[0101] This embodiment combines Figures 3 to 5 This verifies the scientific validity and accuracy of the core of this invention (strength inversion model). The mix proportions of the target component (i.e., the mix proportions of 3D printed concrete) are shown in Table 1:

[0102] Table 1: 3D Printed Concrete Mix Proportions (kg / m³) 3 )

[0103]

[0104] The process of establishing the strength inversion model in this embodiment is as follows: Before printing, the strength inversion model is established in advance. Specifically, eight sets of calibration printing tests are conducted. Taking eight sets of environmental parameters (ambient temperature, ambient relative humidity, and ambient wind speed) as examples, each set of environmental parameters is tested according to interlayer intervals of 10 min, 20 min, 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min, and 120 min. The corresponding moisture evaporation index is then measured, and the actual value of the corresponding interlayer bond strength index is obtained after curing. As an example, the eight sets of environmental parameters are shown in Table 2.

[0105] Table 2: Environmental parameters for 8 sets of calibration printing tests

[0106]

[0107] The data sets obtained from these 8 sets of calibration printing experiments were fitted, and a bivariate quadratic polynomial was used as the basic form of the model: ;in, This refers to the interlayer bond strength index. Interlayer interval, This is the evaporation index. These are the coefficients to be fitted. Mature multivariate nonlinear regression analysis algorithms, such as the least squares method, can be used with MATLAB to fit the experimental dataset and solve for the model coefficients that minimize the error between the model's predicted values ​​and the experimentally measured values. After fitting, the following results were obtained. Given 0.084, b is 0.369, c is -1.942, and d is 0.965, the final expression is: It should be noted that the coefficient c is negative, which conforms to the physical law that interlayer strength decreases with time and moisture evaporation. The coefficient of determination of the fitted surface and the data set obtained from the 8 sets of calibration printing tests was calculated. , specifically Figure 3 As shown, this indicates that the model fits well.

[0108] In the data preprocessing stage, the predicted intensity values ​​are first calculated based on the constructed intensity inversion model. Subsequently, in order to standardize the measurement scale and eliminate the influence of dimensions, the range standardization method was used to standardize the actual intensity values. Compared with predicted intensity value Normalization is then performed. Specifically, the global maximum value is selected from the set of all actual and predicted values. and minimum value According to the formula and Calculation Figure 4 The horizontal axis represents "actual normalized intensity," and the vertical axis represents "predicted normalized intensity," thus mapping the data to... The model's prediction accuracy is visually verified within the interval.

[0109] Figure 4 This is a schematic diagram of the regression fitting of the splitting tensile strength index of concrete based on the time-evaporation index. The upward-sloping dashed line is the 45-degree reference line (i.e., the perfect prediction line, where the actual value is equal to the predicted value). The figure shows that the data points are closely distributed on both sides of the reference line. Through accuracy verification and residual analysis, it is further shown that the predicted value and the measured value are in high agreement.

[0110] Figure 5The residual distribution analysis plot for model prediction is automatically generated by the program to assess the reliability of the model. Figure 5 The horizontal axis represents the normalized predicted intensity value (i.e., the predicted normalized intensity), and the vertical axis represents the residual value (i.e., the actual normalized intensity minus the predicted normalized intensity). The figure includes a y-axis. The black dashed line serves as the baseline reference line, along with two boundary lines representing the mean plus or minus two standard deviations. Statistical data shows that the residual mean is close to 0, and the standard deviation (…) The value is 0.0559. (Through...) Figure 5 As shown in the residual distribution plot, the vast majority of data points are evenly distributed near the zero axis and fall stably. Within the confidence interval, there is no obvious systematic bias, which further proves that the strength inversion model has a highly reliable strength prediction capability in complex construction environments.

[0111] The present invention also provides a 3D printed concrete interlayer bond strength inversion device for performing the 3D printed concrete interlayer bond strength inversion method as described above, comprising:

[0112] The accompanying printing module is used to simultaneously print concrete accompanying specimens in the same environmental field that is physically separate from the target component using the same 3D printing equipment.

[0113] The data acquisition module is used to acquire the weighing monitoring data of the concrete accompanying specimen, and determine the moisture evaporation index based on the weighing monitoring data to reflect the degree of moisture evaporation of the concrete accompanying specimen; and to acquire the printing path timing information of the target component, and determine the actual interlayer interval time based on the printing path timing information to reflect the process state between the current printing layer and the printed layer of the target component.

[0114] The data inversion module is used to input the moisture evaporation index and the actual interlayer interval time into a pre-established strength inversion model, calculate the interlayer bond strength index of the target component at the current printing position in real time, and determine the estimated value of the interlayer bond strength with physical meaning based on the interlayer bond strength index; wherein, the strength inversion model includes the mapping relationship between the moisture evaporation index, the actual interlayer interval time and the interlayer bond strength index;

[0115] The early warning decision module is used to compare the estimated value of the interlayer bond strength with the pre-stored strength threshold, and output the corresponding graded early warning signal based on the comparison result.

[0116] The present invention also provides a 3D printed concrete interlayer bond strength inversion device, including a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, it implements the steps of the 3D printed concrete interlayer bond strength inversion method as described above.

[0117] The present invention also provides a storage medium storing a computer program, which, when executed by a processor, implements the steps of the above-described method for inverting the interlayer bond strength of 3D printed concrete.

[0118] The computer-readable storage medium provided in this application may be, for example, a USB flash drive, but is not limited to, electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices, or any combination thereof. More specific examples of computer-readable storage media may include, but are not limited to: electrical connections having one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. In this embodiment, the computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, system, or device. The program code contained on the computer-readable storage medium may be transmitted using any suitable medium, including but not limited to: wires, optical cables, RF (Radio Frequency), etc., or any suitable combination thereof.

[0119] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural or procedural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of the present invention.

Claims

1. A method for inverting the interlayer bond strength of 3D printed concrete, characterized in that, Includes the following steps: S1, In the same environmental field that is physically separated from the target component, the concrete accompanying specimen is printed simultaneously using the same 3D printing equipment; S2, acquire the weighing monitoring data of the concrete accompanying specimen, and determine the moisture evaporation index to reflect the degree of moisture evaporation of the concrete accompanying specimen based on the weighing monitoring data; and acquire the printing path timing information of the target component, and determine the actual interlayer interval time to reflect the process state between the current printing layer and the printed layer of the target component based on the printing path timing information. S3, input the moisture evaporation index and the actual interlayer interval time into the pre-established strength inversion model, calculate the interlayer bond strength index of the target component at the current printing position in real time, and determine the estimated value of the interlayer bond strength with physical meaning based on the interlayer bond strength index; wherein, the strength inversion model includes the mapping relationship between the moisture evaporation index, the actual interlayer interval time and the interlayer bond strength index; S4, compare the estimated value of the interlayer bond strength with the pre-stored strength threshold, and output the corresponding graded early warning signal according to the comparison result; The intensity inversion model in step S3 is obtained through the following steps: S31, based on the same concrete material mix ratio as the target component, perform multiple sets of calibration printing tests; wherein, each set of calibration printing tests sets a preset interlayer interval time and a set of environmental parameter combinations, and simultaneously prints calibration companion specimens in each set of calibration printing tests; the environmental parameter combinations include ambient temperature, ambient relative humidity and ambient wind speed. S32, In each set of calibration printing tests, monitor the mass change of the calibration companion specimen to determine the moisture evaporation index of the calibration companion specimen, and record the corresponding preset interlayer interval time; S33, after the calibration companion specimens of each group of calibration printing tests have been cured to the specified age, the interlaminar splitting tensile strength of the corresponding calibration companion specimens shall be tested respectively. S34, using formula The actual value of the interlaminar bond strength index of the calibrated specimen was calculated. ;in, This is the measured value of interlaminar splitting tensile strength. The baseline interlaminar splitting tensile strength was obtained from a test without a printing time interval. S35, using the preset interlayer interval time and the moisture evaporation index obtained from multiple sets of calibration printing tests as input samples, and the corresponding actual value of the interlayer bond strength index. As the output sample, the intensity inversion model is obtained by fitting through multivariate nonlinear regression analysis; Step S2, which involves obtaining the weighing monitoring data of the concrete accompanying specimen and determining the moisture evaporation index based on the weighing monitoring data to reflect the degree of moisture evaporation of the concrete accompanying specimen, includes the following steps: Obtain the initial mass of the concrete specimen. And obtain the real-time mass of the concrete specimen obtained by continuous monitoring by the weighing sensor. ; Using formula Calculate the cumulative evaporation water volume of the concrete specimen. ; Based on the initial total water content of the concrete specimens. and the cumulative evaporation volume According to the formula The moisture evaporation index was obtained. .

2. The method for inverting the interlayer bond strength of 3D printed concrete according to claim 1, characterized in that, Step S2, which involves obtaining the printing path timing information of the target component and determining the actual interlayer interval time reflecting the process status between the current printing layer and the already printed layers of the target component, includes the following steps: The motion control command stream of the 3D printing equipment is read in real time to obtain the current moment when the target component arrives at the preset position point in the current printing layer; Retrieve and obtain the printing completion time of the preset position point at the corresponding position in the previous printing layer from the database storing the historical printing time sequence of the target component; The actual interlayer interval time at the preset location point is calculated based on the current time and the printing completion time.

3. The method for inverting the interlayer bond strength of 3D printed concrete according to claim 2, characterized in that, During the execution of step S2, the following environmental adaptive monitoring steps are also executed in parallel: Real-time acquisition of current environmental parameters, and comparison of current environmental parameters with baseline environmental parameters recorded when the concrete specimen printing begins, to obtain the environmental parameter difference; Determine whether the difference in the environmental parameters is greater than or equal to a preset environmental mutation threshold; When the difference in the environmental parameters is greater than or equal to the preset environmental mutation threshold, the reference environmental parameters are updated to the current environmental parameters, and the 3D printing equipment is controlled to reprint a new concrete accompanying specimen as the subsequent monitoring object after completing the current printing task. At the same time, the updated reference environmental parameters and the new concrete accompanying specimen are used as the new reference and new object for data acquisition in step S2. When the difference in environmental parameters is less than a preset environmental mutation threshold, the current concrete specimen and the baseline environmental parameters are maintained and used in step S2.

4. The method for inverting the interlayer bond strength of 3D printed concrete according to claim 1, characterized in that, Step S4 includes the following steps: The estimated interlayer bond strength is compared with a pre-stored strength safety threshold and a strength warning threshold; wherein the strength threshold includes a strength safety threshold and a strength warning threshold, and the strength safety threshold is greater than the strength warning threshold; Based on the comparison results, when the estimated value of the interlayer bond strength is greater than or equal to the strength safety threshold, a first state signal is output, and the current printing parameters are maintained to continue working; When the estimated interlayer bond strength is less than the strength safety threshold and greater than or equal to the strength warning threshold, a second state signal is output and a process adjustment instruction for shortening the subsequent interlayer interval time is generated. When the estimated interlayer bond strength is less than the strength warning threshold, a third state signal is output, and an intervention command is generated to immediately enhance the current interlayer interface bond performance.

5. The method for inverting the interlayer bond strength of 3D printed concrete according to claim 4, characterized in that, Following step S4, the following steps are also included: Establish a mapping relationship between the estimated interlayer bond strength and the three-dimensional printing path coordinates of the target component; Based on the mapping relationship, the different numerical ranges of the estimated interlayer bond strength are mapped to different preset colors, generating and updating in real time a mass distribution cloud map covering the structural shape represented by the 3D printing path coordinates, so as to visualize the spatial distribution of interlayer bond strength.

6. A device for inverting the interlayer bond strength of 3D-printed concrete, used to perform the method for inverting the interlayer bond strength of 3D-printed concrete as described in any one of claims 1-5, characterized in that, include: The accompanying printing module is used to simultaneously print concrete accompanying specimens in the same environmental field that is physically separate from the target component using the same 3D printing equipment. The data acquisition module is used to acquire the weighing monitoring data of the concrete accompanying specimen, and determine the moisture evaporation index based on the weighing monitoring data to reflect the degree of moisture evaporation of the concrete accompanying specimen; and to acquire the printing path timing information of the target component, and determine the actual interlayer interval time based on the printing path timing information to reflect the process state between the current printing layer and the printed layer of the target component. The data inversion module is used to input the moisture evaporation index and the actual interlayer interval time into a pre-established strength inversion model, calculate the interlayer bond strength index of the target component at the current printing position in real time, and determine the estimated value of the interlayer bond strength with physical meaning based on the interlayer bond strength index; wherein, the strength inversion model includes the mapping relationship between the moisture evaporation index, the actual interlayer interval time and the interlayer bond strength index; The early warning decision module is used to compare the estimated value of the interlayer bond strength with the pre-stored strength threshold, and output the corresponding graded early warning signal based on the comparison result.

7. A device for inverting the interlayer bond strength of 3D printed concrete, characterized in that, The method includes a memory, a processor, and a computer program stored in the memory and running on the processor, wherein the processor executes the computer program to implement the steps of the method for inverting the interlayer bond strength of 3D printed concrete as described in any one of claims 1 to 5.

8. A storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the method for inverting the interlayer bond strength of 3D printed concrete as described in any one of claims 1 to 5.

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