Assembly type sleeve production quality tracing system based on digital twinning

Abstract

The application belongs to the technical field of production quality tracing, and relates to a prefabricated sleeve production quality tracing system based on digital twinning, which comprises a sample twinning creation module, an identity recognition coding module, a processing appearance synchronization module, an impedance measurement and collection module, a twinning model correction module, a virtual performance simulation module and a digital archive generation module; a standard calibration sleeve is prepared, and a three-dimensional digital model thereof is constructed; an initial digital twin is created; contact characteristic bands are simultaneously inscribed; contact impedance is measured to generate an appearance deviation data set; the digital twin is corrected according to the data set to generate a final-state digital twin; grouting and gripping force simulation is performed on the final-state model in a virtual environment to obtain a predictive quality evaluation index; and finally, a complete traceable digital archive is generated. The application solves the problems of difficult quantitative detection of the microscopic appearance of the inner wall of the sleeve, weak correlation between physical products and performance data, and difficult quality tracing.

Description

Technical Field

[0001] This invention belongs to the technical field of production quality traceability, and relates to a production quality traceability system for assembled sleeves based on digital twins. Background Technology

[0002] In the field of prefabricated buildings, grouting connection of rebar sleeves is a crucial step in ensuring structural integrity and seismic performance. The processing quality of the inner wall of the sleeve, especially the microstructure of the threaded area, determines the mechanical interlocking and friction between the grout and the sleeve, affecting the final bond strength. However, the inner wall of the sleeve is a typical semi-enclosed, concealed space, and the micro-undulations and processing consistency of its internal structure are difficult to detect accurately, non-destructively, and comprehensively using conventional methods.

[0003] Currently, the mainstream sleeve quality inspection methods in the industry are based on the logic of macroscopic geometric dimension compliance, mainly including two aspects: one is destructive tensile testing after statistical sampling, and the other is to use standard measuring tools to manually inspect key dimensions such as the pitch diameter of the thread to determine whether they fall within the tolerance zone. The core assumption of these two existing technical solutions is that geometric dimensions that meet the preset tolerance are equivalent to meeting the mechanical performance requirements.

[0004] However, common geometric measurement methods are insufficient to quantify the microscopic undulations and roughness of the inner wall surface. These microscopic features are precisely the key physical variables that determine the actual contact area and contact stress distribution between the sleeve and the grout, thus affecting the gripping force. Traditional testing methods make it difficult to accurately correlate the physical product with the test results to each specific sleeve. Once a connection problem occurs on site, it is difficult to efficiently and accurately trace back to the specific state and potential defects in the manufacturing process through data. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a digital twin-based assembly sleeve production quality traceability system.

[0006] The assembly sleeve production quality traceability system based on digital twins includes the following modules:

[0007] The standard twin creation module generates a standard three-dimensional digital model of the standard calibration sleeve.

[0008] The identification and coding module is used to etch an identification mark onto the sleeve to be processed and create an initial digital twin bound to it;

[0009] The processing morphology synchronization module is used to process the inner wall of the production sleeve, simultaneously engraving contact feature bands that reflect the micro-morphology of the inner wall, and outputting a semi-finished sleeve.

[0010] The impedance measurement and acquisition module is used to physically connect the standard calibration sleeve and the semi-finished sleeve, measure the contact impedance between the two, and generate a morphology deviation dataset.

[0011] The twin model correction module corrects the deformation of the initial digital twin based on the shape deviation dataset, generating the final digital twin.

[0012] The virtual performance simulation module is used to simulate the grouting and gripping force of the final-state digital twin in a virtual environment to obtain predictive quality evaluation indicators.

[0013] The digital archive generation module is used to bind predictive quality evaluation indicators with identity identifiers to generate traceable digital archives.

[0014] A further aspect of the present invention generates a standard three-dimensional digital model, comprising the following steps:

[0015] Samples are selected from the same batch of raw materials and processed according to preset process parameters to obtain standard calibration sleeves;

[0016] Perform a full-area scan on the standard calibration sleeve and collect point cloud data of its inner wall surface;

[0017] Three-dimensional reconstruction is performed based on point cloud data to generate a standard three-dimensional digital model, and the standard calibration sleeve is saved as a physical reference.

[0018] A further aspect of the present invention involves generating an initial digital twin, comprising the following steps:

[0019] A dot matrix identification code is etched on the end face of the production sleeve raw material to be processed;

[0020] A standard 3D digital model is replicated and defined as an initial digital twin corresponding to the production sleeve. A one-way binding relationship is established between the dot matrix identification code and the initial digital twin.

[0021] A further embodiment of the present invention outputs a semi-finished sleeve, comprising the following steps:

[0022] Load the production sleeves, which are bound with identification tags, into the processing station;

[0023] Perform the internal wall threading process, and at the same time, in the non-threaded stress area of ​​the inner wall of the sleeve, use an insulated tool to carve a continuous contact feature band with constant pressure;

[0024] The output is a semi-finished sleeve with both structural threads and contact feature bands on its inner wall.

[0025] A further aspect of this invention involves generating a morphology deviation dataset, comprising the following steps:

[0026] Insert the standard calibration sleeve into the inner cavity of the semi-finished sleeve to form a physical connection pair;

[0027] An external circuit was constructed to apply an AC excitation signal to the contact feature band of the semi-finished sleeve and the standard calibration sleeve, and the dynamic contact impedance value between the two as the morphology changes was measured.

[0028] Record and process continuous contact impedance signals throughout the entire stroke to generate a morphology deviation dataset reflecting the differences in inner wall morphology.

[0029] A further aspect of the present invention generates a final-state digital twin, comprising the following steps:

[0030] Invoke the initial digital twin bound to the semi-finished sleeve;

[0031] Based on the topographic deviation dataset and the preset mapping relationship, calculate the geometric offset corresponding to each coordinate point on the inner wall surface;

[0032] The inner wall of the initial digital twin is deformed and corrected using geometric offsets to generate a final digital twin that is consistent with the physical structure of the semi-finished sleeve.

[0033] A further aspect of this invention generates predictive quality evaluation indicators, comprising the following steps:

[0034] Import the final state digital twin and the standard steel reinforcement model into the virtual simulation environment for assembly, and define the filling gap between them;

[0035] Simulate the flow, filling, and hardening process of virtual grouting material in the gaps to form a virtual assembly;

[0036] Virtual pull-out loads are applied to virtual assemblies, and the gripping force is calculated based on the integral of the shear stress at the grout-sleeve interface through mechanical simulation, generating predictive quality evaluation indicators.

[0037] A further aspect of this invention involves generating traceable digital archives and factory certificates of conformity, including the following steps:

[0038] The predictive quality evaluation indicators, the final state digital twin model, and the contact impedance data are packaged into a complete data package;

[0039] Associate data packets with dot matrix identification codes to generate traceable digital archives;

[0040] Compare the predictive quality evaluation indicators with the preset safety thresholds. If the requirements are met, generate a certificate of conformity based on the traceability digital archive.

[0041] A further aspect of this invention establishes a one-way binding relationship between the dot matrix identity code and the initial digital twin, comprising the following steps:

[0042] Create a new entry in the mapping table, which stores the correspondence between physical identification code strings and digital model file paths;

[0043] The scanned dot matrix identification code is associated with the model file path of the initial digital twin created for the production sleeve, forming a one-way binding relationship.

[0044] In a further embodiment of the present invention, the cutting tip of the insulating tool is made of a conductive material. When scribing the contact feature band, the insulating tool generates radial displacement under constant pressure following the microscopic undulations of the inner wall, wherein the depth of the contact feature band is inversely proportional to the height of the inner wall.

[0045] In summary, the present invention has the following beneficial technical effects:

[0046] 1. By simultaneously marking contact feature bands during the production process and using standard calibration sleeves as physical benchmarks for connection mutual inspection, the microscopic morphological differences of the inner wall of the sleeve are converted into measurable continuous electrical impedance signals, enabling near-full-area non-destructive scanning and digital characterization of the inner wall of each production sleeve, thus solving the coverage blind spot problem of traditional sampling inspection methods.

[0047] 2. By using a standard calibration sleeve as a known reference, and measuring the dynamic contact impedance between the standard sleeve and the production sleeve, a morphological deviation dataset is generated. This provides a means to quantify morphological features that are difficult to observe directly, such as microscopic undulations of the inner wall, into specific electrical data.

[0048] 3. Based on the topography deviation dataset, the initial digital twin is reverse-deformed to generate the final digital twin, which reflects the real machining tool marks, local undulations and other micro-geometric features of the corresponding physical sleeve. This provides a more realistic object model for subsequent virtual simulation and improves the model fidelity.

[0049] 4. By using a final-state digital twin in a virtual environment to simulate the grouting process and calculate the gripping force, predictive quality evaluation indicators can be obtained. This enables predictive assessment of the connection performance of each sleeve without physical destructive testing, which helps to identify potential quality risks in the early stages of production.

[0050] 5. By establishing a binding relationship between dot matrix identification codes and digital archives, key information such as physical verification data during the production process, the corrected final-state twin model, and predicted performance indicators are linked and stored to form a complete traceability digital archive, providing data support for quality management and problem tracing throughout the product lifecycle. Attached Figure Description

[0051] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings are used to provide a further understanding of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0052] Figure 1 This discloses a schematic diagram of the framework in the embodiments of this application.

[0053] Figure 2 This discloses a flowchart of an embodiment of this application. Detailed Implementation

[0054] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0055] The following is in conjunction with the appendix Figure 1 - Figure 2 A preferred description of the present invention is provided below.

[0056] See attached document Figure 1 and Figure 2 This invention proposes a digital twin-based assembly sleeve production quality traceability system, comprising the following modules:

[0057] The standard twin creation module generates a standard three-dimensional digital model of the standard calibration sleeve.

[0058] The identification and coding module is used to etch an identification mark onto the sleeve to be processed and create an initial digital twin bound to it;

[0059] The processing morphology synchronization module is used to process the inner wall of the production sleeve, simultaneously engraving contact feature bands that reflect the micro-morphology of the inner wall, and outputting a semi-finished sleeve.

[0060] The impedance measurement and acquisition module is used to physically connect the standard calibration sleeve and the semi-finished sleeve, measure the contact impedance between the two, and generate a morphology deviation dataset.

[0061] The twin model correction module corrects the deformation of the initial digital twin based on the shape deviation dataset, generating the final digital twin.

[0062] The virtual performance simulation module is used to simulate the grouting and gripping force of the final-state digital twin in a virtual environment to obtain predictive quality evaluation indicators.

[0063] The digital archive generation module is used to bind predictive quality evaluation indicators with identity identifiers to generate traceable digital archives.

[0064] In one embodiment of the present invention, generating a standard three-dimensional digital model includes the following steps:

[0065] Samples are selected from the same batch of raw materials and processed into standard calibration sleeves according to preset process parameters; the standard calibration sleeves are scanned in their entirety to collect point cloud data of their inner wall surface; three-dimensional reconstruction is performed based on the point cloud data to generate a standard three-dimensional digital model, and the standard calibration sleeves are saved as a physical reference.

[0066] Specifically, a single steel pipe is randomly selected from the same smelting furnace and rolling batch as a sample. It should be noted that the same batch of steel pipes refers to a group of steel pipes produced from the same furnace of molten steel and using the same rolling process, with no statistically significant differences in chemical composition and mechanical properties. Pre-set optimal process parameters are used. These optimal process parameters are a specific set of data, including the spindle speed of the lathe, feed rate, depth of cut, and the pressure and speed of the rolling roller. The parameters are set based on the optimized parameter combination obtained by analyzing the relationship between product qualification rate and parameters in more than 200 sets of historical production data. The aim is to make the product dimensions most stable and concentrated at the tolerance median. The selected steel pipe sample is then machined on a high-precision CNC lathe. The machining objective is to ensure that all physical dimensions of the manufactured sleeve, including outer diameter, inner diameter, length, and the thread height and pitch of the inner wall thread, are within the midpoint of the tolerance range specified in the design drawings. In other words, the physical dimensions being within the tolerance midpoint means that the actual machining measurement value of each critical design dimension of the sleeve is exactly equal to the arithmetic mean of its allowable upper and lower deviations.

[0067] After processing, a standard calibration sleeve with physical dimensions within the tolerance range is obtained. Then, a high-precision 3D laser scanner is used. This scanner is a non-contact measuring device utilizing the principle of laser triangulation, capable of capturing the microscopic morphology of the sleeve's inner wall threads and performing a comprehensive, blind-spot-free scan of the standard calibration sleeve's inner wall threads and internal cavity structure. The laser beam emitted by the scanner collects point cloud data from the inner wall surface. This point cloud data is automatically stitched and 3D reconstructed using accompanying software to generate a standard 3D digital model consistent with the physical entity of the standard calibration sleeve. It should be understood that this model is a digital surface mesh model composed of triangular facets formed by connecting the massive amount of point cloud data obtained from the scan using algorithms. Its data structure is a mesh model, capable of accurately reflecting the geometry of the physical entity. This model is a digital mesh containing all coordinate points of the inner wall surface.

[0068] Finally, the completed standard verification sleeve entity is stored separately and defined as a physical reference for subsequent quality comparison. Simultaneously, the generated standard 3D digital model is stored as an independent digital file in a designated location in a central database. This database is a computer system used to store and manage all models and data. This model is marked as the fundamental skeleton model that must be relied upon for the subsequent derivation and construction of digital twins for all sleeves produced in the same batch; that is, it serves as the initial template for creating individualized digital twins.

[0069] It should be noted that the physical reference object refers to a physical sleeve that is specially marked and stored, whose dimensions are used as a comparison benchmark for this batch of products, and there is at least one physical sleeve used as a comparison benchmark. The database is a computer system used to store and manage all models and data. The basic skeleton is a digital 3D model representing the ideal median state without any individualized modifications.

[0070] In one embodiment of the present invention, the structure of the standard calibration sleeve can be specifically designed to enable subsequent electrical measurements during its fabrication. For illustration, the standard calibration sleeve is used as the male end, and the production sleeve as the female end. The outer wall threaded area of ​​the standard calibration sleeve is not a continuous conductive solid, but rather one or more continuous annular grooves are machined in the thread crest area. These grooves are filled with high-strength insulating materials, such as Teflon or ceramic coatings, and the grooves cover the entire thread flank, thereby dividing the conductive threaded contact area into several independent conductive regions axially. Simultaneously, at its very front end, i.e., the end into which the production sleeve is first inserted, a precisely machined, uninsulated annular conductive reference surface, referred to as the reference annular surface, is designed. The axial width and radial position of the reference annular surface are precisely designed and controlled to form a unique, stable, measurable electrical contact point in the contact feature zone area on the inner wall of the production sleeve throughout the entire insertion stroke. The tail end of the standard calibration sleeve is led out to the measurement circuit via a wire.

[0071] For example, a batch of steel pipe raw materials with grade Q001 and furnace number A001 is selected, and one pipe is randomly selected. Based on optimized process parameters, such as a spindle speed of 800 r / min and a feed rate of 0.15 mm / r, it is machined on a CNC lathe to obtain a standard calibration sleeve. After verification by a coordinate measuring machine, its actual inner diameter is within the design tolerance. Subsequently, a 3D scanner is used to scan the inner wall of the standard calibration sleeve, and the generated standard 3D digital model reproduces the thread shape of the inner wall. This standard calibration sleeve is labeled: Reference Part – Batch A001 and stored in a constant temperature metrology chamber. Its corresponding standard 3D digital model file is stored in the reference model library directory on the server, serving as the basic framework for constructing digital twins of all subsequent sleeves in this batch.

[0072] In one embodiment of the present invention, generating an initial digital twin includes the following steps:

[0073] A dot matrix identification code is etched on the end face of the production sleeve raw material to be processed; a standard three-dimensional digital model is copied and defined as the initial digital twin corresponding to the production sleeve, and a one-way binding relationship is established between the dot matrix identification code and the initial digital twin.

[0074] Specifically, firstly, a laser marking machine with a pulse width in the nanosecond range is used. The laser marking machine is a device that uses a high-energy-density laser beam to vaporize or change the color of the material surface, thereby leaving a permanent mark. The nanosecond-level pulse width ensures clear markings and a small heat-affected zone. The etching operation is performed on the designated end face area of ​​the raw material for producing the sleeve. The laser beam burns according to a predefined pattern, forming a dot matrix composed of micron-level concave dots. This dot matrix encodes the furnace number information of the steel pipe raw material and the unique serial number information within this batch, which together form a micro dot matrix identification code. The micro dot matrix identification code is a physical graphic code composed of tiny concave dots formed by laser burning on the metal surface arranged according to specific rules. Its data structure includes raw material traceability information and individual identification information.

[0075] Subsequently, a fixed industrial vision scanning device is positioned at the end face. This device is an industrial vision system integrating a high-resolution camera and a dedicated decoding algorithm. Its function is to acquire images of the micro-dot matrix identification code and convert them into readable numerical strings. It captures the image of the micro-dot matrix identification code and uses decoding software to identify the furnace number A001 and serial number 0001 contained within it in real time. The scanning device uploads the identified identification information string to the system backend, which refers to the server software running data management, model copying, and association logic. Upon receiving this identification information, the system backend automatically performs a data copying operation—the process by which the computer system generates a new, independent file on the storage medium that is completely identical to the original file's data content. A standard 3D digital model file named "B_A001.stl" is retrieved from the database, and a copy file is created for it. The system renames this copy file to "Twin_A001_0001" and defines this renamed model as the initial digital twin of the specific production sleeve material. The initial digital twin refers to a three-dimensional digital model file obtained by copying the standard three-dimensional digital model, which has not yet incorporated any production data specific to this individual sleeve. Its file name is bound to specific identity information, and its geometric state represents the ideal median value. This twin is currently consistent with the standard three-dimensional digital model in terms of geometric shape.

[0076] Next, the system creates new entries in its internal mapping table, a two-dimensional table stored in the database. Each record stores a physical identification code string and the corresponding digital model file path. A forced association is established between the physical world's micro-dot matrix identification code A001_0001 and the digital world's model file "twin_A001_0001," locking this as a one-to-one, unchangeable, unidirectional binding relationship. This setting ensures the uniqueness and immutability of the traceability chain's origin. Finally, the system outputs a production sleeve with a unique micro-dot matrix identification code on its physical end and an initial digital twin already bound to it in digital space, completing the initial mapping from physical entity to digital space.

[0077] One-way binding means that the corresponding digital twin can be uniquely queried from the physical identity code, but it is prohibited to modify or unbind the corresponding physical identity information through the digital twin.

[0078] For example, for the aforementioned batch of raw materials for production sleeves, firstly, a laser marking machine etches a micro-matrix identification code, such as A001_0001, onto its end face. Then, a scanning device reads this code and uploads the string. The system then copies the file "B_A001.stl", generates a new file named "Twin_A001_0001.stl", and identifies it as the initial digital twin of the sleeve with serial number 0001. The system creates a record in the mapping table: A001_0001 corresponds to the model file "Twin_A001_0001.stl". At this point, the raw material for production sleeves is given a physical identifier and possesses a unique digital mapping entity, becoming a sleeve to be processed with an identification mark.

[0079] In one embodiment of the present invention, the output of a semi-finished sleeve includes the following steps:

[0080] The production sleeve with the identification mark is loaded into the processing station; the internal wall threading process is performed, and at the same time, in the non-threaded stress area of ​​the sleeve's inner wall, a continuous contact feature band is engraved with an insulated tool under constant pressure; the semi-finished sleeve with both structural threads and contact feature bands on the inner wall is output.

[0081] Specifically, firstly, the sleeve to be processed is loaded onto a dedicated machining station on a CNC machine tool using automated handling equipment or manual operation. This machining station is the position on the CNC machine tool used to clamp and fix the sleeve for processing, equipped with hydraulic or pneumatic fixtures for precise radial and axial positioning. After positioning, the CNC program is started to execute the conventional internal thread rolling process. It should be understood that this process is a mature manufacturing process that uses high-hardness thread rolling wheels under a preset feed pressure to extrude and plastically deform the inner wall of the sleeve, thereby forming a continuous internal thread structure with a specific tooth profile.

[0082] While the thread rolling wheel is processing, another independent tool control unit begins operation. This unit drives a specially designed insulated tool, a special tool whose head is composed of a conductive material, such as cemented carbide, used for etching the trajectory; the tool shank is made of insulating materials such as alumina ceramic to ensure high resistance between the tool head and the machine tool body. The insulated tool applies a constant preset pressure, which is maintained stable through closed-loop control by a high-precision pressure sensor. The pressure setting is based on process test results that produce a clear trajectory without causing excessive deformation of the inner wall material. Then, on the flat area of ​​the inner wall of the sleeve, adjacent to the threaded area but not the main stress-bearing surface, i.e., the non-threaded stress area, a continuous spiral or straight groove encircling the inner wall is etched. This groove is the contact feature zone. It should be understood that the non-threaded stress area refers to the area on the inner wall of the sleeve that does not directly participate in the engagement of the reinforcing bar thread and is not subject to the main shear stress, usually a flat band between the thread roots or a specially reserved annular area.

[0083] During the engraving process, due to the inherent micro-undulations of the inner wall of the sleeve after threading, the tip of the insulating tool will undergo a slight up-and-down displacement. As a result, the actual physical depth of the contact feature band is not constant, but changes synchronously with the micro-undulations of the inner wall surface. The trajectory depth is inversely proportional to the local height of the inner wall.

[0084] Once the routine internal thread machining and contact feature band marking are completed simultaneously, the machine tool stops working and the fixture is released. The sleeve output at this time has structural threads on its inner wall for connection and anchoring, as well as a contact feature band with a depth that varies with the morphology for subsequent electrical testing. This sleeve is defined as a semi-finished sleeve, that is, a sleeve product that has completed the machining of the key internal wall structure and added special testing features, but has not yet undergone final quality inspection and information binding.

[0085] Conventional internal thread rolling or cutting processes refer to mature manufacturing processes that form standard thread shapes on the inner wall of a sleeve by extrusion with rolling rollers or cutting with a lathe tool. The contact feature band is a continuous, conductive fine groove formed through physical etching. Microscopic undulations refer to random height variations on the machined inner wall surface, at the micrometer level, caused by material inhomogeneity, tool vibration, or plastic deformation.

[0086] For example, the device is loaded onto a CNC thread rolling machine and internal thread rolling is performed. Simultaneously, under program control, an insulated tool etchs a continuous contact feature band on the annular band between the thread roots with a constant pressure of 5 N. Due to the actual presence of minute ripples on the internal wall, the measured trajectory depth fluctuates between 10 μm and 30 μm, rather than being a constant value. After machining, a semi-finished sleeve with both a complete thread and a continuous conductive groove on the internal wall is obtained, and its identification code remains A001_0001.

[0087] In one embodiment of the present invention, generating a morphology deviation dataset includes the following steps:

[0088] A standard calibration sleeve is inserted into the inner cavity of the semi-finished sleeve to form a physical connection pair; an external circuit is constructed to apply an AC excitation signal to the contact feature band of the semi-finished sleeve and the standard calibration sleeve, and the dynamic contact impedance value between the two as the morphology changes is measured; the continuous contact impedance signal throughout the entire stroke is recorded and processed to generate a morphology deviation dataset reflecting the differences in the inner wall morphology.

[0089] Specifically, firstly, the prepared standard calibration sleeve is used as the male plug, and its outer thread area is aligned with the inner thread area of ​​the semi-finished sleeve. With the assistance of a precision guide device, the standard calibration sleeve is smoothly inserted into the inner cavity of the semi-finished sleeve along the axial direction until the two reach the preset mating depth. At this time, the inner and outer threads of the two sleeves mesh with each other, and their contact surfaces form a physical connection pair.

[0090] Subsequently, the electrical measurement phase begins. A four-probe measurement circuit is constructed to eliminate the influence of lead resistance. A high-frequency AC excitation signal with a constant amplitude, such as a constant current of 100mA with a frequency of 10kHz-1MHz, is applied to the measurement circuit. Macroscopically, the two metal sleeves form a conductive path due to their large-area contact via threads. However, according to Holm's contact resistance theory, the actual contact on the metal surfaces is achieved by a large number of micro-protrusions, limiting the effective contact area. The measured dynamic contact impedance is much smaller than the nominal contact area, and this area fluctuates with changes in surface microstructure. Therefore, the measured dynamic contact impedance... It primarily reflects the change in effective contact area determined by microstructure, rather than simple DC resistance.

[0091] During the entire insertion, rotation, or withdrawal stroke of the standard calibration sleeve, the contact impedance value is continuously measured at a sampling frequency of not less than 1 kHz. This impedance value is related to the local microscopic gap. The relationship can be described by the following semi-empirical model:

[0092] ;

[0093] in, For the first The impedance values ​​measured at each sampling point; The reference background impedance generated by the tight engagement of the threads is a constant. To follow the local micro gap A function of varying effective contact area; and These are coefficients pre-calibrated based on the resistivity of the same batch of materials and the characteristics of the measurement system; For measuring noise.

[0094] When there are microscopic protrusions on the inner wall Decrease Enlargement, leading to Decrease; conversely, when there are microscopic depressions on the inner wall. Increase Decrease rise.

[0095] Finally, the system processes the acquired raw impedance curves. The time axis is converted into a spatial position axis based on the known geometry of the standard calibration sleeve, and the impedance fluctuation component corresponding to each spatial position point is extracted. A topographic deviation dataset is generated using this fluctuation component. Each record in this dataset contains the spatial coordinates of the inner wall. And the quantitative value at this point reflecting the actual morphological deviation of the inner wall of the semi-finished sleeve relative to the outer wall of the standard calibration sleeve. ,Right now This dataset serves as direct input for subsequent reverse reconstruction of the digital model.

[0096] Among them, the morphology deviation dataset is a structured collection of data in which each data record associates the spatial coordinates of the inner wall with a calculated numerical value that characterizes the difference between the actual morphology and the ideal morphology at that location.

[0097] For example, continuing from the previous example, a standard calibration sleeve with identification code A001_0001 is inserted into the semi-finished sleeve. A four-probe measurement circuit is connected, and an AC excitation current of 100mA and 1kHz is applied. During the entire process of insertion and rotation, due to the uneven microstructure of the inner wall, the measured dynamic contact impedance fluctuates between 2.5 mΩ and 3.2 mΩ, with the metal contact impedance in the milliohm range. This fluctuation curve is recorded and calibrated to convert it into a position-impedance sequence spiraling along the inner wall. For example, impedance fluctuation values ​​were recorded at a position 50 mm axially from the port and at an angle of 120 degrees. The value of +0.4 mΩ (relative to the baseline) indicates that there may be microscopic depressions on the inner wall of the semi-finished sleeve at this location, resulting in a reduction in the effective contact area. This dataset characterizes the morphological deviation of the inner wall of this individual sleeve.

[0098] In one embodiment of the present invention, generating a final-state digital twin includes the following steps:

[0099] The initial digital twin bound to the semi-finished sleeve is invoked; based on the shape deviation dataset and the preset mapping relationship, the geometric offset corresponding to each coordinate point on the inner wall surface is calculated; the deformation correction of the inner wall of the initial digital twin is performed using the geometric offset to generate a final digital twin consistent with the physical structure of the semi-finished sleeve.

[0100] Specifically, firstly, the initial digital twin bound to the semi-finished sleeve is invoked in the digital model processing software; this model is a mesh model representing the ideal median state. Simultaneously, the generated morphology deviation dataset is loaded.

[0101] For each sampling point in the dataset Based on a preset mapping function, the precise distance that the corresponding mesh vertex should move along its normal direction is calculated, i.e., the geometric offset. The mapping function was obtained through a previously designed artificial defect calibration experiment, and its calculation formula is as follows:

[0102] ;

[0103] in, Coordinates The distance that a grid vertex needs to move along the normal, in micrometers; a positive value indicates inward concavity, and a negative value indicates outward convexity. This is the measured impedance fluctuation value; It is the theoretical impedance fluctuation value of an ideal smooth surface under the same measurement conditions, and is usually close to zero; It is the conversion gain coefficient, which represents the geometric depth change corresponding to the unit impedance fluctuation, and is determined through calibration experiments; It is an axial position correction factor used to compensate for the impact of uneven contact pressure distribution caused by different sleeve insertion depths on the impedance signal.

[0104] The calculation process involves converting the impedance deviation of each data point into a geometric displacement using the formula described above. Next, a reverse reconstruction process is performed, which uses the measured topographic deviation data to drive the digital model to deform in reverse, thereby reconstructing the physical structure.

[0105] Using all the calculated geometric offset data, the mesh deformation function of the model processing software is driven. This function applies the corresponding displacement vector at each vertex position based on the smooth inner wall mesh of the initial digital twin. ,in This is the unit normal vector at that vertex, causing local bulges or depressions on the originally smooth and ideal mesh surface. This process is called mesh deformation correction, and its function is to make the geometry of the digital model highly match the real microscopic morphology of the physical entity.

[0106] The deformation correction process accurately simulates the microstructural features of the actual physical entity of the semi-finished sleeve caused by the processing, including but not limited to the machining marks left by the tool travel, the uneven thread depth caused by uneven pressure, and the slight ellipticity deviation caused by the release of clamping stress.

[0107] After mesh deformation is complete, the corrected model undergoes geometric topology checks and data solidification to ensure it is a complete, closed, error-free, and computable 3D model. Finally, this solidified model is saved as a new, independent file, for example, named "Final-State Twin_A001_0001". This model is the final-state digital twin that highly matches the physical microstructure of the semi-finished sleeve, serving as the digital endpoint for quality traceability.

[0108] For example, the "twin_A001_0001" model is invoked, and the morphological deviation dataset is read. Assume that for the data recorded in the dataset: axial length 50mm, angle 120 degrees... Data points, known ideal values Calibration coefficient The position correction factor .

[0109] Calculate the geometric offset using the formula:

[0110] ;

[0111] Then, at the corresponding coordinate point of the model, the mesh vertex is moved inward by 10 μm along the inner wall normal. After repeating this process to process all data points, the initially smooth inner wall mesh becomes uneven, simulating the microscopic morphology of the actual inner wall of the sleeve. After correction, the model is fixed and saved as "final state twin_A001_0001". The inner wall of this model shows a 10 μm deep micro-pit at the corresponding position, consistent with the defect location and scale of the physical entity, becoming a high-fidelity final state digital twin.

[0112] In one embodiment of the present invention, generating predictive quality evaluation indicators includes the following steps:

[0113] Import the final-state digital twin and the standard steel bar model into the virtual simulation environment for assembly, and define the filling gap between them; simulate the flow, filling and hardening process of virtual grout in the filling gap to form a virtual assembly; apply virtual pull-out load to the virtual assembly, and generate predictive quality evaluation indicators through mechanical simulation and based on the integral of the shear stress at the grout-sleeve interface.

[0114] Specifically, firstly, in a computer virtual simulation software environment, such as finite element analysis software, the final-state digital twin is called and loaded as the simulated sleeve body. Next, a standard steel bar digital model matching the sleeve design specifications is imported from a standard parts model library. In the software, the standard steel bar model is axially aligned and virtually assembled and inserted into the sleeve cavity represented by the final-state digital twin, with the two automatically maintaining a preset uniform gap to accommodate the virtual grouting material according to their geometric definitions.

[0115] Subsequently, the grouting condition simulation phase begins. In the material properties module of the simulation software, predefined constitutive model parameters for the virtual grout are loaded. For example, the Drucker-Prager model is used to simulate its elastoplastic behavior, with parameters set according to the technical parameters of commonly used high-strength grout products in actual engineering. The filling simulation is then initiated, calculating the entire process of the virtual grout flowing into and filling the gap between the inner wall of the sleeve and the outer wall of the reinforcing bar, a complex and irregular surface defined by the final-state twin, under gravity or a preset pressure. After filling, the hardening process of the grout is simulated, where the hardened grout bonds with the inner wall of the sleeve and the surface of the reinforcing bar.

[0116] Finally, mechanical property simulation was performed. A virtual pull-out load along the axial direction was applied to the hardened virtual assembly, namely the sleeve-grout-reinforcement assembly, with the load gradually increasing at a constant rate. The simulation software calculated the stress and deformation inside the assembly in real time based on the finite element method.

[0117] The sleeve's ultimate grip strength prediction index By the interface between the grout and the inner wall of the sleeve The shear stress is obtained by integrating the stress, and the calculation formula is as follows:

[0118] ;

[0119] And any point on the interface shear force Failure criteria must be met:

[0120] ;

[0121] in, It is a complex contact surface uniquely determined by the geometry of the inner wall of the final state digital twin; For a point on the contact surface Local shear stress at the location; The angle between the tangential direction of the local contact surface and the drawing direction is affected by the thread profile and machining defects. The shear strength limit of the grout itself; Interfacial friction and adhesion force calculated based on the Mohr-Coulomb criterion; The normal compressive stress at this point is directly affected by the unevenness of the inner wall morphology. The coefficient of friction; The stress is determined by the bonding force; the simulation software solves the mechanical equilibrium equations to determine the stress distribution, and calculates the ultimate load that causes interface failure based on the aforementioned integral formula. The system will do this The numerical values ​​serve as core parameters to generate predictive quality evaluation indicators for the production sleeve, such as the ultimate gripping force value or a safety factor calculated based on it.

[0122] To verify the effectiveness of the simulation method, a comparative calibration is required: Samples from the same batch of the standard calibration sleeve are selected, and the virtual predicted grip force is calculated using the same simulation procedure. Simultaneously, a standard sleeve-reinforcement connector monotonic axial tensile test is performed on the sample sleeve, and the actual grip force is measured. Through comparison of multiple sets of samples, it is confirmed that the error between the virtual predicted grip force and the actual grip force is within an acceptable engineering range, for example, a relative error ≤15%, thus proving that the simulation method can effectively predict the grip performance of the sleeve. Finally, the system outputs predictive quality evaluation indicators for the individual sleeve corresponding to the final state digital twin, namely its virtual predicted grip force value and safety factor.

[0123] For example, in simulation software such as ANSYS, the "final state twin_A001_0001" is called to import a standard steel reinforcement model for virtual assembly, set the grout properties, and simulate filling and hardening. Because the final state twin reproduces the microscopic ripples of the inner wall, the contact interface... It is more complex than the ideal model. After applying a pull-out load, the software calculates the stress distribution based on the aforementioned integral formula. Assume that the ultimate gripping force of the virtual assembly is ultimately calculated. The value is 245 kN. The system records this value and generates a predictive quality evaluation index: ultimate gripping force 245 kN, safety factor 1.8, assuming a design requirement of 200 kN; this index predicts the connection performance of the sleeve in actual engineering.

[0124] In one embodiment of the present invention, generating a traceability digital archive and a certificate of conformity includes the following steps:

[0125] The predictive quality evaluation indicators, the final state digital twin model, and the contact impedance data are packaged into a complete data package; the data package is associated with the dot matrix identification code to generate a traceability digital file; the predictive quality evaluation indicators are compared with the preset safety thresholds, and if the requirements are met, a certificate of conformity is generated based on the traceability digital file.

[0126] It should be noted that the insulated cutting tool is used for marking under constant pressure control. When the tool reaches the microscopic protrusions on the inner wall, the local pressure increases, but due to the slight elasticity of the tool system, the cutting head will produce a slight upward displacement, resulting in a shallower groove depth in the protrusion area; conversely, in the microscopic depression area, the downward displacement of the cutting head increases, and the groove depth is deepened. Therefore, the depth trajectory of the contact feature band naturally and continuously replicates the original height fluctuations after the inner wall thread machining, and an inverse proportional mapping relationship is formed between the two. To achieve a quantitative conversion from the measured contact impedance value to the geometric shape deviation, a preliminary calibration experiment is required. The specific method is as follows: prepare a series of metal samples with stepped or sloping artificial grooves of known depth, and use the same standard calibration sleeve and measuring circuit as the production inspection to measure the contact impedance value corresponding to each groove of known depth. Through data fitting, such as linear or polynomial regression, establish a mathematical model or lookup table of "impedance change - groove depth change", that is, determine the conversion gain coefficient k in the aforementioned deformation correction step. This calibration relationship needs to be periodically checked due to differences in material batches, surface conditions, and measurement systems. Through the above mechanism and calibration, it is ensured that each data point in the morphology deviation dataset accurately reflects the microscopic geometric deviation of the inner wall of the production sleeve relative to the standard part, thus providing a reliable data foundation for high-fidelity correction of the digital twin.

[0127] Specifically, firstly, a data aggregation operation is performed, creating a new data packet container. The predictive quality evaluation indicators, the final-state digital twin model file, and the contact impedance curve data file are treated as independent but interconnected entries, organized according to a predefined structured format, such as JSON or a specific binary encapsulation format, and placed into this data packet. The data within this packet collectively constitutes a core dataset describing the entire lifecycle of this specific sleeve, from physical processing to virtual performance prediction. Subsequently, the system performs data binding and writing operations. Based on the sleeve's unique identification string A001_0001, an initial data entry unidirectionally bound to this identification code is indexed in the database. The newly generated complete data packet is treated as an indivisible whole, appended to and associated with this database entry, thus forming a complete, logically consistent, and tamper-proof traceable digital archive due to the writing sequence and association relationships.

[0128] Finally, the system executes a factory exit decision. It reads predictive quality evaluation indicators from the data packet, such as the ultimate grip strength of 245 kN, and compares it with a preset safety threshold. This safety threshold is a minimum acceptable value pre-set according to design specifications, industry standards, and safety factor requirements, for example, 200 kN. If the comparison result shows that the indicator value is greater than or equal to the safety threshold, the system automatically triggers the certificate of conformity generation process. Based on key information in the traceability digital file, such as the identification code, indicator value, and production date, it generates an electronic certificate of conformity document and stores this certificate as the final record in the archive. At this point, the finished sleeve, possessing a unique physical identity, a high-fidelity digital mirror, accompanying full-cycle quality data and performance prediction conclusions, and capable of panoramic backtracking at any time by scanning the identification code, is output, realizing a closed-loop quality traceability system based on digital twins.

[0129] Packaging and aggregation refers to the operation of integrating data files or data streams from multiple sources and in various formats into a logically single data unit through software encapsulation technology. Its function is to ensure the integrity and relevance of the data. Traceability digital archives are digital records that are permanently bound to a unique physical identity code in the database and record the key data set of the entire life cycle of the product. Its data structure allows all information to be queried and historical versions to be traced. The immutability is achieved through database transaction consistency, writing logs, and strong association of data packets with previously established binding relationships, ensuring the credibility of the archives. The preset safety threshold is a critical value used to determine whether a product is qualified. Its setting is based on the technical standards for grouting sleeve connection performance issued by the state or industry, product design document requirements, and the safety margin of the enterprise's internal control. The quality traceability closed loop refers to starting from the identification of raw materials, going through processing, testing, modeling, simulation and prediction, and finally gathering all data and conclusions and binding them back to the original identity to form a complete data loop that is connected end to end and allows information to be traced forward and backward.

[0130] For example, the aforementioned ultimate grip strength index of 245 kN, the final twin file _A001_0001.stl, and the impedance curve file are packaged into a data packet. Then, the entry corresponding to the identification code A001_0001 is located in the database, and this data packet is written. Since 245 kN is greater than the preset safety threshold of 200 kN, the system automatically generates a certificate of conformity, indicating that the product is qualified, with an ultimate grip strength of 245 kN, and stores it in the archive. Finally, the sleeve with the identification code A001_0001 is shipped as a finished product, and all its production and quality data are locked in the digital archive, completing the traceability loop.

[0131] Each of the modules can be implemented in whole or in part through software, hardware, or a combination thereof. It supports hardware embedded in or independent of the processor in the computer device, and also supports software stored in the memory of the computer device, so that the processor can call and execute the operations corresponding to each of the above modules.

[0132] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A digital twin-based assembly sleeve production quality traceability system, characterized in that, Includes the following modules: The standard sample twin creation module generates a standard three-dimensional digital model based on the standard calibration sleeve. The identification and coding module is used to etch an identification mark onto the sleeve to be processed and create an initial digital twin bound to it; The processing morphology synchronization module is used to process the inner wall of the sleeve to be processed, and simultaneously engrave contact feature bands that reflect the micro-morphology of the inner wall, and output semi-finished sleeves. The impedance measurement and acquisition module is used to physically connect the standard calibration sleeve and the semi-finished sleeve, measure the contact impedance between the two, and generate a morphology deviation dataset. The twin model correction module corrects the deformation of the initial digital twin based on the shape deviation dataset, generating the final digital twin. The virtual performance simulation module is used to simulate the grouting and gripping force of the final state digital twin in a virtual environment to obtain predictive quality evaluation indicators. The digital archive generation module is used to bind predictive quality evaluation indicators with identity identifiers to generate traceable digital archives; The process of outputting semi-finished sleeves includes: loading the sleeves to be processed, which are bound with identification marks, into the processing station; performing the internal wall thread processing process; and simultaneously using an insulated tool to carve a continuous contact feature band in the non-threaded stress area of ​​the sleeve's inner wall with constant pressure; and outputting a semi-finished sleeve whose inner wall contains both structural threads and contact feature bands. The process of generating the morphology deviation dataset includes: inserting a standard calibration sleeve into the inner cavity of the semi-finished sleeve to form a physical connection pair; constructing an external circuit to apply an AC excitation signal to the contact feature band of the semi-finished sleeve and the standard calibration sleeve, and measuring the dynamic contact impedance value between the two as the morphology changes; recording and processing the continuous contact impedance signal throughout the entire stroke to generate a morphology deviation dataset that reflects the differences in the inner wall morphology. The predictive quality evaluation index is obtained by: importing the final state digital twin and the standard steel bar model into the virtual simulation environment for assembly, and defining the filling gap between them; simulating the flow, filling and hardening process of virtual grout in the filling gap to form a virtual assembly; applying virtual pull-out load to the virtual assembly, and obtaining the bond force through mechanical simulation and based on the integral calculation of the shear stress at the contact interface between the grout and the inner wall of the sleeve, thus generating the predictive quality evaluation index.

2. The assembly sleeve production quality traceability system based on digital twin as described in claim 1, characterized in that, Generating a standard 3D digital model includes the following steps: Samples are selected from the same batch of raw materials and processed according to preset process parameters to obtain standard calibration sleeves; Perform a full-area scan on the standard calibration sleeve and collect point cloud data of its inner wall surface; Three-dimensional reconstruction is performed based on point cloud data to generate a standard three-dimensional digital model, and the standard calibration sleeve is saved as a physical reference.

3. The assembly sleeve production quality traceability system based on digital twin as described in claim 1, characterized in that, Creating the initial digital twin associated with it includes the following steps: A dot matrix identification code is etched on the end face of the raw material for the sleeve to be processed; A standard 3D digital model is copied and defined as an initial digital twin corresponding to the sleeve to be processed, and a one-way binding relationship is established between the dot matrix identification code and the initial digital twin.

4. The assembly sleeve production quality traceability system based on digital twin as described in claim 1, characterized in that, Generating a final-state digital twin includes the following steps: Invoke the initial digital twin bound to the semi-finished sleeve; Based on the topographic deviation dataset and the preset mapping function, calculate the geometric offset corresponding to each coordinate point on the inner wall surface; The inner wall of the initial digital twin is deformed and corrected using geometric offsets to generate a final digital twin that is consistent with the physical structure of the semi-finished sleeve.

5. The assembly sleeve production quality traceability system based on digital twin as described in claim 1, characterized in that, Generating a traceable digital archive includes the following steps: Predictive quality assessment metrics, final-state digital twins, and contact impedance data are packaged into a complete data package; Associate data packets with dot matrix identification codes to generate traceable digital archives; Compare the predictive quality evaluation indicators with the preset safety thresholds. If the requirements are met, generate a certificate of conformity based on the traceability digital archive.

6. The assembly sleeve production quality traceability system based on digital twin according to claim 3, characterized in that, Establishing a one-way binding relationship between the dot matrix identity code and the initial digital twin includes the following steps: Create a new entry in the mapping table, which stores the correspondence between physical identification code strings and digital model file paths; The scanned dot matrix identification code is associated with the model file path of the initial digital twin created for the sleeve to be processed, forming a one-way binding relationship.

7. The assembly sleeve production quality traceability system based on digital twin as described in claim 1, characterized in that, The cutting tip of the insulating tool is made of conductive material. When it scratches the contact feature band, the insulating tool generates radial displacement under constant pressure due to the microscopic undulations of the inner wall. The depth of the contact feature band is inversely proportional to the height of the inner wall.

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