Passive intelligent bolt simulation model construction method based on stress discoloration method

Abstract

The invention discloses a passive intelligent bolt simulation model construction method based on a stress discoloration method, and relates to the technical field of firmware simulation, and the method comprises the following steps: constructing a fastening load equivalent model, and building a parameterized simulation entrance; constructing a finite element model of the assembly based on the equivalent pre-tightening force, and obtaining a stress state of a color developing element; constructing a piezochromism simulation model of the color developing element and realizing mechanical-optical quantity conversion; constructing fastening process parameters, and performing dynamic simulation of color development evolution in the fastening process; performing color development response reliability simulation analysis based on parameter disturbance; and a passive intelligent bolt multi-physics field coupling simulation model is formed. According to the method, quantitative prediction and procedural analysis from the fastening behavior to the color development result are achieved by establishing the unified coupling relation between the models, and the influences of different structure parameters and material parameters on the color development effect are accurately evaluated in the design stage; and the consistency and the stability of the color development response of the passive intelligent bolt are improved through quasi-dynamic simulation and reliability analysis.

Description

Technical Field

[0001] This invention relates to the field of firmware simulation technology, specifically to a method for constructing a passive smart bolt simulation model based on the stress-color change method. Background Technology

[0002] Bolts are among the most common and critical fasteners in engineering structures, and their tightness directly affects equipment operation safety and structural reliability. Current technologies primarily rely on torque control, angle control, or active sensing methods such as strain, resistance, and electromagnetic induction to assess bolt tightness. These technologies generally suffer from several drawbacks. First, the torque-preload relationship is significantly affected by friction conditions and assembly process fluctuations, making it difficult to accurately reflect the true stress state. Second, active monitoring solutions typically require the deployment of sensors, power supply units, and signal acquisition modules, resulting in complex structures, high costs, and insufficient reliability under complex operating conditions such as high temperature, high humidity, and strong electromagnetic interference.

[0003] In recent years, stress-sensitive color-changing passive smart bolt solutions have emerged, utilizing the visible color change of compressive color-changing materials under stress to provide a new technical path for intuitive and passive identification of fastening states. However, existing research mainly focuses on the material color phenomenon or structural prototype verification, lacking a systematic simulation model construction method to quantitatively describe the intrinsic coupling relationship between "fastening load—structural force transmission—force on color-changing element—optical response." In particular, regarding the evolution of the fastening process, structural force transmission efficiency, and the impact of parameter uncertainties on the color-changing results, a reusable and predictable simulation analysis system has not yet been formed, resulting in insufficient controllability and consistency of the color-changing effect during the design phase. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a method for constructing a passive intelligent bolt simulation model based on the stress-color change method, thereby solving the problems mentioned in the background section.

[0005] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, the present invention provides a method for constructing a passive smart bolt simulation model based on the stress-color change method, comprising the following steps: S1. Construct an equivalent model of the fastening load and establish a parameterized simulation entry point; The equivalent model of fastening load takes the fastening torque of the bolt as input and converts the fastening torque into an equivalent preload based on the nominal diameter of the bolt and the equivalent torque coefficient. S2. Construct a finite element model of the assembly based on the equivalent preload and obtain the stress state of the color display element; A finite element model of the assembly is established, and the fastening state is solved by applying the equivalent preload. The equivalent preload is mapped to the equivalent nominal stress acting on the color display element, which is used to characterize the mechanical result of the fastening load being transmitted to the color display element through the structural path. S3. Construct a pressure-induced color-changing simulation model of the color-producing element and realize the mechanical-optical quantity conversion; Based on the pressure-induced color change simulation model of the color-producing element, the correspondence between the equivalent nominal stress and the change of the periodic spacing of the photonic crystal is established, and the main reflection wavelength of the color-producing element under the action of the equivalent nominal stress is calculated, realizing the quantitative conversion from mechanical stress to observable optical response. S4. Construct fastening process parameters and perform dynamic simulation of the color evolution of the fastening process; The equivalent preload is applied to the assembly simulation model according to the fastening process parameters. The equivalent nominal stress of the color-producing element under the corresponding process is obtained step by step. The main reflection wavelength under different fastening processes is calculated by combining the compressive color change simulation model to obtain the evolution relationship between the fastening process and the color-producing response. S5. Reliability simulation analysis of colorimetric response based on parameter perturbation; By applying a predetermined perturbation range to the parameters, the fastening process simulation is repeatedly executed without changing the topology of the assembly structure. The distribution characteristics of the main reflection wavelength under different parameter combinations are obtained, and the sensitivity and stability of the colorimetric response to manufacturing errors and structural deviations are evaluated. S6. Form a multi-physics coupling simulation model of passive smart bolts; The processes of steps S1 to S5 are modularly integrated to form a simulation model for the design, analysis and verification of passive smart bolts, realizing the system-level coupling expression between fastening force, structural stress and color response.

[0006] To further optimize this technical solution, the equivalent model of the fastening load constructed in step S1 is shown below:

[0007] in, This is the equivalent preload, expressed in N. The tightening torque applied to the bolt, expressed in N·m; This is the equivalent torque coefficient; This is the nominal diameter of the bolt, in meters (m). The model outputs It serves as the driving input for the finite element model fastening simulation of the assembly.

[0008] To further optimize this technical solution, in step S2, the finite element model of the assembly adopts the following layered component modeling strategy: The bolt metal body, transparent protective layer, color-developing cavity structure, and color-changing core are defined by their respective material and contact properties. The contact pairs employ openable and closable frictional contacts to capture localized slippage tendencies during the fastening process.

[0009] To further optimize this technical solution, the finite element model of the assembly is shown below:

[0010] in, The equivalent nominal stress acting on the effective pressure surface of the colorimetric element is expressed in Pa. The structural force transmission coefficient reflects the proportion and concentration effect of the cavity structure in distributing the axial preload of the bolts to the pressure area of ​​the color rendering element. The effective pressure-bearing area of ​​the colorimetric element, in units of ; The model outputs This serves as the macroscopic equivalent load for the color-changing element in the pressure-induced color change simulation model.

[0011] To further optimize this technical solution, in step S3, the pressure-induced color change simulation model of the color-developing element is as follows:

[0012] in, For color rendering elements under equivalent nominal stress The primary reflection wavelength under action, in meters; The equivalent refractive index of the colorimetric element; The equivalent periodic spacing of the photonic crystal is expressed in meters. The equivalent compression factor is used to... The scaling factor mapped to the relative spacing compression, in units .

[0013] To further optimize this technical solution, in step S4, the fastening process parameters... In a finite element environment, this parameter is used to describe the entire process of fastening from initial contact to the target torque; it does not represent actual time, but is only used as a loading progress variable, with a value range between 0 and 1.

[0014] To further optimize this technical solution, the fastening process parameters In the simulation settings, the tightening torque is... or equivalent preload The preload is applied proportionally, meaning that in any loading step, the actual applied equivalent preload is... ; In each loading step, the finite element model outputs an equivalent nominal stress corresponding to the color-developing element. Based on the pressure-induced color-changing simulation model, the corresponding primary reflection wavelength was obtained. Thus The result of a single operating condition is transformed into a state function that changes with the fastening process.

[0015] To further optimize this technical solution, in step S5, the selected parameters include the equivalent torque coefficient. Structural force transmission coefficient Effective pressure-bearing area of ​​color rendering element and equivalent compression coefficient ; The predetermined disturbance range is a symmetrical interval of small disturbances around the nominal value.

[0016] To further optimize this technical solution, in step S6, modular integration includes: The equivalent model of fastening load, the finite element model, the pressure-induced color change simulation model, the dynamic simulation of step S4, and the reliability analysis of step S5 are encapsulated at the system level.

[0017] To further optimize this technical solution, in step S6, after modular integration, the simulation model of this method includes a fastening load equivalent and structural force transmission simulation module, a pressure-induced color change response calculation module, and a process and reliability analysis module.

[0018] In a second aspect, the present invention provides a computer device, including a memory and a processor, wherein the memory stores a computer program, wherein: when the computer program instructions are executed by the processor, they implement the steps of a method for constructing a passive intelligent bolt simulation model based on the stress-color change method as described in the first aspect of the present invention.

[0019] Thirdly, the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein: when the computer program instructions are executed by a processor, the steps of a method for constructing a passive intelligent bolt simulation model based on the stress-coloring method as described in the first aspect of the present invention are implemented.

[0020] Compared with existing technologies, this invention provides a method for constructing a passive smart bolt simulation model based on the stress-color change method, which has the following beneficial effects: This method for constructing a simulation model of passive smart bolts based on the stress-induced color change method establishes a unified coupling relationship between the equivalent model of the fastening load, the finite element model, and the pressure-induced color change simulation model. This enables quantitative prediction and process analysis from fastening behavior to color development results. It can not only accurately assess the impact of different structural and material parameters on the color development effect during the design stage, but also improve the consistency and stability of the color development response of passive smart bolts through quasi-dynamic simulation and reliability analysis. Thus, it provides a highly systematic and feasible simulation analysis method for the structural design, parameter optimization, and engineering application of passive smart bolts. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a flowchart illustrating a method for constructing a passive intelligent bolt simulation model based on the stress-color change method proposed in this invention. Detailed Implementation

[0023] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0024] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0025] Secondly, the term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places throughout this specification does not necessarily refer to the same embodiment, nor is it a single embodiment or an embodiment selectively excluded from other embodiments.

[0026] Example 1: Reference Figure 1 This is the first embodiment of the present invention, which provides a method for constructing a passive smart bolt simulation model based on the stress-color change method, including the following steps: S1. Construct an equivalent model of the fastening load and establish a parameterized simulation entry point; In the parametric simulation environment, the equivalent model of fastening load uses the bolt's fastening torque as input. Based on the bolt's nominal diameter and equivalent torque coefficient, the fastening torque is converted into an equivalent preload. The equivalent torque coefficient is obtained through pre-calibration to ensure consistent representation of fastening behavior under different fastening conditions in the simulation model. The assembly constraints are solidified into a model template in the form of "connected part contact pairs + bolt head / nut support surface contact pairs + threaded pair contact pairs," ensuring that the load transmission topology is not changed during subsequent structural refinement. This establishes a unified load-driven foundation for subsequent structural force transmission and color response analysis.

[0027] The equivalent model of the fastening load is shown below:

[0028] in, This is the equivalent preload, expressed in N. The tightening torque applied to the bolt is expressed in N·m; it is directly given / recorded by an electric torque wrench or torque sensor.

[0029] The equivalent torque coefficient (considering the influence of friction between the threaded pair and the bearing surface, pitch geometry, etc., on torque distribution); obtained through calibration experiments of bolts of the same specification (under the same lubrication / surface conditions, the relationship between preload and torque is measured using force-sensing washers or tension gauges, and taken as the equivalent torque coefficient). The mean as And it is used as the input of operating condition parameters in the simulation parameterization environment.

[0030] This refers to the nominal diameter of the bolt, measured in meters (m); it is determined by the bolt specifications and is specified in the CAD parameter table.

[0031] The model is used as follows: each simulation condition is determined by... Trigger, calculate first Output It serves as the driving input for the finite element model fastening simulation of the assembly.

[0032] S2. Construct a finite element model of the assembly based on the equivalent preload and obtain the stress state of the color display element; A finite element model of the assembly, including the bolt metal body, the cavity structure of the color display element, and the load-bearing structure of the color display element, is established. The fastening state is solved by applying the equivalent preload. Then, based on the effective pressure area of ​​the color display element and the structural force transmission coefficient, the equivalent preload is mapped to the equivalent nominal stress acting on the color display element, which is used to characterize the mechanical result of the fastening load being transmitted to the color display element through the structural path. The core task of this step is not to repeat the "dimensional design" itself, but to parameterize and solidify the structure into a simulation object of the "force flow transmission path": that is, to... After application, the force is transmitted through structural components such as nuts / screws / cavity walls / caps to the pressure-bearing area where the color-developing element is located. Therefore, the finite element model of the assembly adopts the following layered component modeling strategy: The bolt metal body, transparent protective layer, color-developing cavity structure, and color-changing core are defined by their respective material and contact properties. The contact pairs employ openable and closable frictional contacts to capture localized slippage tendencies during the fastening process.

[0033] The core purpose of the layered component modeling strategy in the finite element model is to realistically reproduce the transmission path and mechanical distribution mechanism of the fastening load within the passive smart bolt. Specifically, the bolt metal body, as the main load-bearing component, uses its material properties to describe the elastic deformation characteristics of high-strength steel under axial preload. The transparent protective layer, as the transition interface between mechanics and optics, needs to possess sufficient stiffness to participate in load transmission and also needs to reflect its constraint and protection role for the color-changing element in the model. The color-changing cavity structure undertakes the function of "force flow redirection," and its geometry and material elastic modulus directly affect the distribution of preload within the cavity. The color-changing core column or color-changing element carrier, as the direct force-bearing object of the compressive color-changing response, is defined as an independent component in the model, thus enabling the accurate extraction of the equivalent stress in its compressed area as input for color-changing calculation. Through this layered modeling approach, the mechanical relationships between different functional layers are clearly distinguished, avoiding the simplification of the color-changing element as part of the bolt as a whole, which would lead to stress averaging and color-changing prediction distortion.

[0034] Meanwhile, in modeling the interactions between components, employing openable and closable frictional contact pairs is a key technical means to ensure the credibility of the fastening process simulation. Traditional contact assumptions based on binding or complete adhesion cannot reflect the minute slippage and local contact state changes that may occur during actual fastening. This method, by introducing a contact model with normal opening and closing and tangential friction characteristics, enables controlled contact establishment, pressure concentration, and limited slippage between the bolt body and the color-developing cavity, and between the color-developing cavity and the color-changing core column, during the fastening loading process. This contact modeling approach not only captures the true evolution trend of force flow within the structure as preload is gradually applied, but also avoids deviations in stress estimation of the color-developing element due to the neglect of local slippage, thus providing stable and reliable input conditions for the subsequent stress-wavelength mapping model. This modeling strategy, which balances structural realism and computational controllability, gives this method high simulation consistency and promotional value in engineering applications.

[0035] The finite element model of the assembly is shown below:

[0036] in, The equivalent nominal stress acting on the effective pressure surface of the colorimetric element is expressed in Pa.

[0037] The structural force transmission coefficient reflects the proportion and concentration effect of the cavity structure in distributing the axial preload of the bolts to the pressure area of ​​the color display element; it is obtained by back-calculation from the finite element fastening simulation of the assembly, under given conditions. Under operating conditions, read the average contact pressure on the pressure surface of the colorimetric element. (or mean normal stress), let And it is updated during geometry iteration.

[0038] The effective pressure-bearing area of ​​the colorimetric element, in units of The contact geometry between the color-producing element and the supporting structure is determined and can be directly calculated from the CAD contact projection area and written into the parameter table.

[0039] The model outputs As the macroscopic equivalent load of the color-developing element in the pressure-induced color change simulation model, the dynamic simulation of the fastening process of the complete assembly is used to analyze the displacement change, stress distribution, transmission law and its control effect on the color-developing area.

[0040] S3. Construct a pressure-induced color-changing simulation model of the color-producing element and realize the mechanical-optical quantity conversion; The color-changing mechanism of a color-producing element is as follows: the material, based on the periodic reflection characteristics of a photonic crystal structure, has a fixed structural spacing and reflects a specific wavelength when unloaded; under pressure, the microstructural spacing is compressed, causing a change in the reflected wavelength and thus a color shift; after unloading, it elastically recovers. Based on the pressure-induced color-changing simulation model of the color-producing element, the correspondence between the equivalent nominal stress and the change in the periodic spacing of the photonic crystal is established, and the principal reflection wavelength of the color-producing element under the equivalent nominal stress is calculated, realizing the quantitative conversion from mechanical stress to observable optical response. The simulation model of the compressive color change of the color rendering element is shown below:

[0041] in, For color rendering elements under equivalent nominal stress The primary reflection wavelength under action, in meters; It is the equivalent refractive index of the color rendering element; it can be determined by the material's optical parameters (refractive index test or product parameters).

[0042] The equivalent periodic spacing of the photonic crystal is expressed in meters (m). It can be obtained from the design of the colorimetric element material or the microstructure characterization (e.g., the design value of the microstructure spacing of the colorimetric element sample under no-load conditions or the average value of microscopic measurements) and written into the material parameters.

[0043] The equivalent compression factor is used to... The scaling factor mapped to the relative spacing compression, in units The calibration was obtained through pressure testing of a "separate colorimetric element": stress was calculated under known compressive load and pressure area, and the corresponding change in reflection peak wavelength was measured (using a spectrometer). and Linear fitting can be used to obtain (Within the range of small strain).

[0044] When assembly simulation gives Then, input it into the model for calculation. and put As a subsequent step, optical port quantities are constructed to form a coupled analysis chain of "fastening force-structural stress-micro deformation-color change". Mechanical simulation and optical property data are integrated to initially construct a coupled analysis model and predict the color change trend.

[0045] S4. Construct fastening process parameters and perform dynamic simulation of the color evolution of the fastening process; The equivalent preload is applied to the assembly simulation model according to the fastening process parameters. The equivalent nominal stress of the color-developing element under the corresponding process is obtained step by step. The main reflection wavelength under different fastening processes is calculated by combining the compressive color change simulation model, and the evolution relationship between the fastening process and the color response is obtained.

[0046] After completing steps S1 to S3, a closed but still "static" chain has been formed, defined by the tightening torque. The colorimetric element is obtained through structural force transmission mapping. The primary reflection wavelength was then calculated using the compressive color change mechanism. Dynamic simulation of the fastening process of the complete assembly is performed to analyze the displacement changes, stress distribution, transmission laws of each component, and their control effect on the color development area during the fastening process, reflecting the evolution process of gradually applying load, gradually stressing the structure, and gradually developing color during the fastening process.

[0047] Fastening process parameters In a finite element environment, this parameter is used to describe the entire process of fastening from initial contact to the target torque; it does not represent actual time, but is only used as a loading progress variable, with a value range between 0 and 1.

[0048] The fastening process parameters In the simulation settings, the tightening torque is... or equivalent preload The preload is applied proportionally, meaning that in any loading step, the actual applied equivalent preload is... ; In each loading step, the finite element model outputs an equivalent nominal stress corresponding to the color-developing element. Based on the pressure-induced color-changing simulation model, the corresponding primary reflection wavelength was obtained. Thus The result of a single operating condition is transformed into a state function that changes with the fastening process.

[0049] For each tightening loading step, the average stress in the compressed area of ​​the colorimetric element is extracted and substituted into the model of step S3 to obtain a set of... Discrete points are used to construct the response curve of "tightening process - wavelength change".

[0050] S5. Reliability simulation analysis of colorimetric response based on parameter perturbation; Based on the aforementioned steps, the simulation model is now able to output the color development response evolution curve under ideal parameter conditions, conduct reliability analysis and structural optimization research, and evaluate the impact of long-term use, environmental factors and manufacturing errors on color development performance. Therefore, parameter perturbation is introduced to evaluate the sensitivity and dispersion of the color development response to key factors without making any modifications to the structural or material parameters.

[0051] By applying a predetermined perturbation range to the parameters, the fastening process simulation is repeatedly executed without changing the topology of the assembly structure. The distribution characteristics of the main reflection wavelength under different parameter combinations are obtained, and the sensitivity and stability of the colorimetric response to manufacturing errors and structural deviations are evaluated. The selected parameters include the equivalent torque coefficient. Structural force transmission coefficient Effective pressure-bearing area of ​​color rendering element and equivalent compression coefficient ; The predetermined disturbance range is a symmetrical interval of small disturbances around the nominal value.

[0052] In this way, at each fastening process point... A corresponding set is obtained above The result is a distribution, not a single curve. The core indicator this step focuses on is not the color itself, but the degree of dispersion of the wavelength response. The changing trend, for example, when approaching the target tightened state. Does it exhibit a convergent, stable distribution, or is it highly sensitive to a certain parameter?

[0053] This step helps to identify which parameters have the greatest impact on the color development results and which structural or material properties need to be carefully controlled during manufacturing and assembly.

[0054] S6. Form a multi-physics coupling simulation model of passive smart bolts; The processes of steps S1 to S5 are modularly integrated to form a simulation model for the design, analysis and verification of passive smart bolts, realizing the system-level coupling expression between fastening force, structural stress and color response.

[0055] Modular integration includes: The equivalent model of fastening load, the finite element model, the pressure-induced color change simulation model, the dynamic simulation of step S4, and the reliability analysis of step S5 are encapsulated at the system level.

[0056] After modular integration, the simulation model of this method includes a fastening load equivalent and structural force transmission simulation module, a pressure-induced color change response calculation module, and a process and reliability analysis module.

[0057] Specifically, this step clearly divides the entire method into three interconnected but functionally distinct sub-modules: the first sub-module is the fastening load equivalent and structural force transmission simulation module, corresponding to steps S1 and S2, and its output is the equivalent nominal stress at the color display element. The second submodule is the pressure-induced color change response calculation module, corresponding to step S3, and its input is... The output is the main reflection wavelength. The third submodule is the process and reliability analysis module, corresponding to steps S4 and S5. Its function is to analyze the process and reliability under loading path and parameter disturbance conditions. The evolution and stability of the model are evaluated. This modular definition enables rapid reuse and expansion of the model.

[0058] Furthermore, this step clearly defines how the model can be used: in engineering applications, only the geometric parameters, material parameters, and calibration parameters need to be replaced according to the specific bolt specifications and color-coding element design, without needing to rebuild the entire simulation logic; during the design phase, different structural schemes can be compared and evaluated by repeatedly calling the model; during the verification phase, the experimentally measured wavelength change results can be compared with the simulation output. The effectiveness of the model is verified by comparing the curves. Through the above encapsulation and definition, the method of this invention not only achieves quantitative prediction of "tightening force-color response", but also forms a complete method for constructing a passive intelligent bolt simulation model.

[0059] Example 2: The fastening status of the bolts connecting the wind turbine tower and nacelle is visualized and verified based on the method described in Embodiment 1.

[0060] In large wind turbine units, the flange connection bolts between tower sections and the high-strength bolts between the tower and the nacelle and yaw system are subjected to alternating loads, vibrations and complex environments for a long time. The attenuation or inconsistency of their preload is a major hidden danger that can lead to structural fatigue, loosening or even failure.

[0061] In the bolt design stage, the passive intelligent bolt simulation model construction method based on stress color change method described in this invention is introduced. For the specific specifications, flange structure and expected fastening conditions of high-strength bolts used in wind turbines, a quantitative correspondence relationship of "target fastening torque - equivalent preload - force on color-displaying element - color wavelength change" is first established through the simulation model. This allows for the prediction of the color range and change trend of the color-displaying element under normal fastening, under-tightening and over-tightening conditions. At the same time, combined with the quasi-dynamic simulation of the fastening process, the smoothness of the color evolution and the presence of a clear visual discrimination window under different fastening processes during actual installation are analyzed.

[0062] Before project implementation, this simulation model can be used to conduct reliability analysis on manufacturing errors, friction condition fluctuations, and parameter deviations under long-term service conditions. It verifies whether the colorimetric response maintains stable discrimination under factors such as wind load and temperature difference, thus providing a basis for the design of colorimetric element dimensions, selection of installation locations, and setting of colorimetric thresholds. Ultimately, in field applications, bolt tightness can be quickly determined through visual inspection or simple optical checks, without the need for additional power supply or signal acquisition systems.

[0063] Through this practical application scenario, this method can significantly improve the predictability and visualization of the design and verification of the fastening status of key connection bolts in wind turbine units, reduce the complexity and cost of operation and maintenance, and improve the safety of structural operation. This demonstrates the engineering application value of this simulation model construction method in the design of passive intelligent fasteners for large equipment.

[0064] Example 3: This embodiment also provides a computer device applicable to a method for constructing a passive intelligent bolt simulation model based on the stress-color change method, including a memory and a processor; the memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions to realize the method for constructing a passive intelligent bolt simulation model based on the stress-color change method proposed in the above embodiment.

[0065] This embodiment also provides a storage medium storing a computer program that, when executed by a processor, implements a method for constructing a passive smart bolt simulation model based on the stress-color change method as proposed in the above embodiment.

[0066] The computer device can be a terminal, comprising a processor, memory, communication interface, display screen, and input devices connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The communication interface is used for wired or wireless communication with external terminals; wireless communication can be achieved through Wi-Fi, carrier networks, NFC (Near Field Communication), or other technologies. The display screen can be an LCD screen or an e-ink screen. The input devices can be a touch layer covering the display screen, buttons, a trackball, or a touchpad on the computer device's casing, or an external keyboard, touchpad, or mouse.

[0067] If a function is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0068] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-including system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device.

[0069] More specific examples (a non-exhaustive list) of computer-readable media include: electrical connections (electronic devices) having one or more wires, portable computer disk drives (magnetic devices), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Furthermore, computer-readable media can even be paper or other suitable media on which programs can be printed, because programs can be obtained electronically, for example, by optically scanning the paper or other media, followed by editing, interpreting, or otherwise processing as necessary, and then stored in computer memory.

[0070] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0071] It should be noted that 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 preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for constructing a passive intelligent bolt simulation model based on the stress-color change method, characterized in that, Includes the following steps: S1. Construct an equivalent model of the fastening load and establish a parameterized simulation entry point; The equivalent model of fastening load takes the fastening torque of the bolt as input and converts the fastening torque into an equivalent preload based on the nominal diameter of the bolt and the equivalent torque coefficient. S2. Construct a finite element model of the assembly based on the equivalent preload and obtain the stress state of the color display element; A finite element model of the assembly is established, and the fastening state is solved by applying the equivalent preload. The equivalent preload is mapped to the equivalent nominal stress acting on the color display element, which is used to characterize the mechanical result of the fastening load being transmitted to the color display element through the structural path. S3. Construct a pressure-induced color-changing simulation model of the color-producing element and realize the mechanical-optical quantity conversion; Based on the pressure-induced color change simulation model of the color-producing element, the correspondence between the equivalent nominal stress and the change of the periodic spacing of the photonic crystal is established, and the main reflection wavelength of the color-producing element under the action of the equivalent nominal stress is calculated, realizing the quantitative conversion from mechanical stress to observable optical response. S4. Construct fastening process parameters and perform dynamic simulation of the color evolution of the fastening process; The equivalent preload is applied to the assembly simulation model according to the fastening process parameters. The equivalent nominal stress of the color-producing element under the corresponding process is obtained step by step. The main reflection wavelength under different fastening processes is calculated by combining the compressive color change simulation model to obtain the evolution relationship between the fastening process and the color-producing response. S5. Reliability simulation analysis of colorimetric response based on parameter perturbation; By applying a predetermined perturbation range to the parameters, the fastening process simulation is repeatedly executed without changing the topology of the assembly structure. The distribution characteristics of the main reflection wavelength under different parameter combinations are obtained, and the sensitivity and stability of the colorimetric response to manufacturing errors and structural deviations are evaluated. S6. Form a multi-physics coupling simulation model of passive smart bolts; The processes of steps S1 to S5 are modularly integrated to form a simulation model for the design, analysis and verification of passive smart bolts, realizing the system-level coupling expression between fastening force, structural stress and color response.

2. The method for constructing a passive intelligent bolt simulation model based on the stress-color change method according to claim 1, characterized in that, In step S1, the equivalent model of the fastening load is constructed as follows: ； in, This is the equivalent preload, expressed in N. The tightening torque applied to the bolt, expressed in N·m; This is the equivalent torque coefficient; This is the nominal diameter of the bolt, in meters (m). The model outputs It serves as the driving input for the finite element model fastening simulation of the assembly.

3. The method for constructing a passive intelligent bolt simulation model based on the stress-color change method according to claim 1, characterized in that, In step S2, the finite element model of the assembly adopts the following layered component modeling strategy: The bolt metal body, transparent protective layer, color-developing cavity structure, and color-changing core are defined by their respective material and contact properties. The contact pairs employ openable and closable frictional contacts to capture localized slippage tendencies during the fastening process.

4. The method for constructing a passive intelligent bolt simulation model based on the stress-color change method according to claim 3, characterized in that, The finite element model of the assembly is shown below: ； in, The equivalent nominal stress acting on the effective pressure surface of the colorimetric element is expressed in Pa. The structural force transmission coefficient reflects the proportion and concentration effect of the cavity structure in distributing the axial preload of the bolts to the pressure area of ​​the color rendering element. The effective pressure-bearing area of ​​the colorimetric element, in units of ; The model outputs This serves as the macroscopic equivalent load for the color-changing element in the pressure-induced color change simulation model.

5. The method for constructing a passive intelligent bolt simulation model based on the stress-color change method according to claim 1, characterized in that, In step S3, the pressure-induced color change simulation model of the color-developing element is shown below: ； in, For color rendering elements under equivalent nominal stress The primary reflection wavelength under action, in meters; The equivalent refractive index of the colorimetric element; The equivalent periodic spacing of the photonic crystal is expressed in meters. The equivalent compression factor is used to... The scaling factor mapped to the relative spacing compression, in units .

6. The method for constructing a passive intelligent bolt simulation model based on the stress-color change method according to claim 1, characterized in that, In step S4, the fastening process parameters In a finite element environment, it is used to describe the entire process of fastening from initial contact to the target torque; This parameter does not represent the actual time; it is only used as a loading progress variable, and its value ranges from 0 to 1.

7. The method for constructing a passive intelligent bolt simulation model based on the stress-color change method according to claim 6, characterized in that, The fastening process parameters In the simulation settings, the tightening torque is... or equivalent preload The preload is applied proportionally, meaning that in any loading step, the actual applied equivalent preload is... ; In each loading step, the finite element model outputs an equivalent nominal stress corresponding to the color-developing element. Based on the pressure-induced color-changing simulation model, the corresponding primary reflection wavelength was obtained. Thus The result of a single operating condition is transformed into a state function that changes with the fastening process.

8. The method for constructing a passive intelligent bolt simulation model based on the stress-color change method according to claim 1, characterized in that, In step S5, the selected parameters include the equivalent torque coefficient. Structural force transmission coefficient Effective pressure-bearing area of ​​color rendering element and equivalent compression coefficient ; The predetermined disturbance range is a symmetrical interval of small disturbances around the nominal value.

9. The method for constructing a passive intelligent bolt simulation model based on the stress-color change method according to claim 1, characterized in that, In step S6, modular integration includes: The equivalent model of fastening load, the finite element model, the pressure-induced color change simulation model, the dynamic simulation of step S4, and the reliability analysis of step S5 are encapsulated at the system level.

10. The method for constructing a passive intelligent bolt simulation model based on the stress-color change method according to claim 1, characterized in that, In step S6, after modular integration, the simulation model of the method includes a fastening load equivalent and structural force transmission simulation module, a pressure-induced color change response calculation module, and a process and reliability analysis module.

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