A threaded seal quick judgment method based on intelligent sensor

Abstract

The application relates to the technical field of threaded sealing, and discloses a threaded sealing rapid judgment method based on an intelligent sensor, which comprises the following steps: synchronously collecting sound wave signals arranged outside a threaded joint and transient pressure signals of a fluid cavity inside the threaded joint; extracting penetrating acoustic total energy and dynamic pressure fluctuation sequences; calculating an expansion length and a spatial acoustic resistance decay coefficient based on threaded sizes; converting dynamic pressure fluctuation perturbation into a micro leakage volume equivalent; calculating fluid-solid coupling sealing impedance; combining material properties to deduce a theoretical benchmark impedance and generate an adaptive judgment threshold; and finally comparing numerical values to output a judgment result.

Description

Technical Field

[0001] This invention relates to the field of thread sealing technology, specifically to a method for rapid determination of thread seals based on intelligent sensors. Background Technology

[0002] In modern industrial pipelines, precision instruments, and high-pressure vessels, the sealing performance of threaded connections is a core requirement for ensuring system safety and performance. Common testing methods involve applying test pressure directly after assembly and determining the connection's suitability by monitoring pressure maintenance or directly observing signs of leakage. However, a very subtle and uncommon technical problem exists in the current industry of rapid thread seal assessment: the misjudgment due to the "transient seal illusion." Specifically, in the initial stage of thread engagement, especially in scenarios where liquid sealant needs to be applied and tested before it fully cures, uncured adhesive and micro-air bubbles remaining in the microscopic mechanical engagement dead zones within the thread gap can create a "false pressure holding" state for a short period. This phenomenon leads to a brief pressure balance, making it difficult for techniques relying solely on pressure decay indicators or traditional torque feedback signals to distinguish this transient pressure holding caused by fluid surface tension and temporary micro-air chamber blockage from a true, durable, and dense physical contact seal. Consequently, connections that are not fully engaged or have potential problems are often misjudged as compliant. As the equipment continues to operate for extended periods, it is subjected to vibration loads or alternating temperature conditions. These temporary micro-cavities are highly susceptible to rupture or adhesive displacement, leading to severe delayed leaks. To address seal detection, existing advanced judgment algorithms often rely on empirically set fixed judgment thresholds or use big data-dependent iterative learning models. These methods are not only ill-suited for threaded joints with specific geometric tolerances and varying material physical properties, but also fail to thoroughly resolve the issue of misjudging seal artifacts during specific transient windows because they do not delve into the essential physical relationship between sound wave propagation loss and internal micro-pressure changes within the thread structure.

[0003] Therefore, how to solve the above problems is a technical challenge that urgently needs to be addressed by those skilled in the art. Summary of the Invention

[0004] This invention provides a method for rapid determination of thread seals based on intelligent sensors, which helps to solve the problems mentioned in the background art.

[0005] This invention provides the following technical solution: a method for rapid determination of thread seals based on intelligent sensors, comprising:

[0006] The acoustic excitation signal and the corresponding acoustic reception signal set outside the threaded joint are collected synchronously, as well as the transient pressure signal set inside the fluid cavity of the thread.

[0007] The received acoustic signal is integrated in the time domain within a time window to extract the total penetrating acoustic energy, and the transient pressure signal is stripped of its initial static base value to obtain a dynamic pressure micro-fluctuation sequence.

[0008] The actual unfolded length of the spiral microchannel is calculated based on the macroscopic geometric parameters of the thread, and the spatial acoustic retardation attenuation coefficient is calculated by combining the initial excitation energy and the total penetrating acoustic energy.

[0009] The absolute rate of change of the dynamic pressure micro-fluctuation sequence is extracted and integrated in the time domain to obtain the cumulative dynamic pressure relief micro-perturbation.

[0010] By utilizing the initial volume of the internal fluid cavity and the inherent compressibility of the fluid, the accumulated dynamic pressure relief perturbation is converted into the equivalent of structural micro-leakage volume.

[0011] The morphological compensation factor is extracted by combining the thread profile features. The maximum tolerance gap volume is calculated based on the tolerance gap area and the actual unfolded length. Then, the fluid-structure coupling sealing impedance is calculated by combining the acoustic hysteresis attenuation coefficient and the micro-leakage volume equivalent.

[0012] Based on the inherent physical properties of the thread material, the theoretical reference impedance under ideal conditions is derived, and an adaptive dynamic judgment threshold is generated by combining the geometric tolerance distribution of the thread surface.

[0013] The real-time calculated fluid-structure interaction sealing impedance is compared with the adaptive dynamic judgment threshold, and the final thread sealing status judgment result is output based on the comparison result.

[0014] Optionally, the synchronous acquisition of the acoustic excitation signal and corresponding acoustic reception signal located outside the threaded joint, as well as the transient pressure signal located inside the fluid cavity of the thread, specifically includes:

[0015] A piezoelectric acoustic wave exciter is deployed on the outer wall of the male end of the threaded connector; an acoustic emission receiving sensor is deployed on the outer wall of the female end; a high-frequency dynamic pressure sensor is deployed in the internal fluid cavity of the threaded connection; the initial amplitude of the standard excitation signal emitted by the exciter and the total length of the sampling time window are acquired; within the sampling time window, the time-series acoustic envelope signal acquired by the acoustic emission receiving sensor and the time-series transient pressure signal acquired by the pressure sensor are acquired synchronously; known parameters are acquired, including the standard thread pitch, nominal thread diameter, actual number of turns engaged, thread profile half angle, standard tolerance clearance cross-sectional area, initial volume of the internal fluid cavity, fluid bulk modulus, density of the thread metal material, and standard propagation speed of sound waves in the material.

[0016] Optionally, the step of performing time-domain integration on the received acoustic signal within a time window to extract the total penetrating acoustic energy, and stripping the transient pressure signal of its initial static baseline to obtain a dynamic pressure micro-fluctuation sequence, specifically includes:

[0017] The square value of the acquired time-series acoustic envelope signal is integrated in the time domain within the sampling time window, and the integration result is used as the total received acoustic energy penetrating the thread engagement zone within the entire sampling time window.

[0018] By subtracting the static internal pressure baseline value acquired at the initial moment from the acquired time-series transient pressure signal, a dynamic pressure micro-fluidity sequence is obtained to characterize the fluid's micro-escape response.

[0019] Optionally, the calculation of the actual unfolded length of the helical microchannel based on the macroscopic geometric parameters of the thread, and the calculation of the spatial acoustic hindrance attenuation coefficient by combining the initial excitation energy and the total penetrating acoustic energy, specifically includes:

[0020] The circumference is calculated based on the nominal diameter of the thread. The unfolded length of a single turn of the helix is ​​determined by the calculated circumference and the standard thread pitch. The unfolded length of the single turn of the helix is ​​multiplied by the actual number of turns to obtain the true unfolded length of the helical microchannel through which the sound waves and fluid actually pass.

[0021] Calculate the product of the square of the initial amplitude of the standard excitation signal and the total length of the sampling time window; solve for the natural logarithm of the ratio of this product to the total received acoustic energy; divide the value of this natural logarithm by the actual unfolded length of the spiral microchannel to calculate the path-normalized spatial acoustic attenuation coefficient.

[0022] Optionally, the step of extracting the absolute rate of change from the dynamic pressure micro-fluctuation sequence and performing a time-domain integration operation to obtain the cumulative dynamic pressure relief micro-perturbation specifically includes:

[0023] Calculate the derivative of the dynamic pressure micro-fluctuation sequence with respect to time; take the absolute value of the derivative result.

[0024] Within the sampling time window, the derivative result after taking the absolute value is integrated in the time domain to extract the cumulative dynamic pressure relief perturbation.

[0025] Optionally, the step of utilizing the initial volume of the internal fluid cavity and the inherent compressibility properties of the fluid to convert the accumulated dynamic pressure relief perturbation into the equivalent of structural micro-leakage volume specifically includes:

[0026] Calculate the product of the cumulative dynamic pressure relief perturbation and the initial volume of the internal fluid cavity; divide the product by the fluid volume elastic modulus to convert the pressure perturbation into the equivalent of the structural microleakage volume.

[0027] Optionally, the step of extracting the morphological compensation factor based on the thread profile features, calculating the maximum tolerance gap volume based on the tolerance gap area and the actual unfolded length, and then calculating the fluid-structure interaction sealing impedance by combining the acoustic hysteresis attenuation coefficient and the micro-leakage volume equivalent, specifically includes:

[0028] Calculate the cosine value of the thread profile half angle; calculate the reciprocal of the above cosine value as the morphological compensation factor for the sound wave transmission of the thread profile inclination angle.

[0029] Multiply the standard tolerance clearance cross-sectional area by the actual unfolded length of the spiral microchannel to calculate the theoretically maximum allowable tolerance micro-cell void volume at that screw length;

[0030] Calculate the ratio of the structural microleak volume equivalent to the maximum tolerance micro-cell volume; multiply the spatial acoustic retardation attenuation coefficient by the morphological compensation factor to obtain the first product; add one to the ratio to obtain the divisor; divide the first product by the divisor to calculate the fluid-structure interaction sealing impedance characteristic quantity characterizing the true sealing state of the joint.

[0031] Optionally, the step of deriving the theoretical reference impedance under ideal conditions based on the inherent physical properties of the thread material, and generating an adaptive dynamic judgment threshold by combining the geometric tolerance distribution of the thread surface, specifically includes:

[0032] Multiply the density of the threaded metal material, the standard propagation speed of sound in the material, and the morphological compensation factor; divide the result of the above three multiplications by the actual unfolded length of the helical microchannel to calculate the pure analytical theoretical acoustic emission reference impedance under absolutely ideal contact conditions;

[0033] Calculate the product of the nominal diameter of the thread, the standard pitch of the thread, and pi; calculate the ratio of the standard tolerance clearance cross-sectional area to the product of the above three; subtract the above ratio from one to obtain the tolerance factor; multiply the theoretical acoustic emission reference impedance by the tolerance factor to give the reference impedance an adaptive dynamic structural tolerance margin, and generate the final adaptive dynamic judgment threshold.

[0034] Optionally, the step of comparing the real-time calculated fluid-structure interaction sealing impedance with the adaptive dynamic judgment threshold, and outputting the final thread sealing state judgment result based on the comparison result, specifically includes:

[0035] Subtract the adaptive dynamic judgment threshold from the calculated fluid-structure interaction sealing impedance; take the mathematical sign function value of the result after subtraction to obtain the final sealing judgment indicator variable; when the final sealing judgment indicator variable is equal to positive one, the judgment result is that the thread engagement is sufficient and there is no false pressure, which is a true safe seal; when the final sealing judgment indicator variable is equal to negative one, the judgment result is that there are transient sealing illusions caused by incomplete air bubbles or glue displacement inside.

[0036] The present invention has the following beneficial effects:

[0037] 1. This solution is designed for specific industrial rapid testing environments in which threaded connections are initially engaged or before the liquid sealant cures. In this environment, residual microbubbles or uncured adhesive in the thread gap can easily form unstable "transient sealing illusions," making traditional methods relying on a single pressure drop for judgment face serious failure risks. The reason this solution adopts an acoustic-pressure fusion architecture is to utilize the extremely high sensitivity of acoustic emission waves to the solid engagement state, combined with the ability of high-frequency dynamic pressure sensors to capture fluid disturbances, to physically dismantle and penetrate this transient equilibrium state. Its unique beneficial effect lies in reconstructing the helical propagation path and calculating the fluid-structure interaction. Coupled sealing impedance digitally links the microscopic tooth engagement quality with the macroscopic pressure relief volume, thereby automatically deriving the absolute threshold for judgment based solely on the material properties and geometric tolerances of the parts themselves, without relying on any human experience or requiring massive sample training. This makes the solution highly adaptable and accurate when facing high-turnover automated production lines, and can eliminate "false seal" products that, although temporarily leak-free, have structural defects within a very short window before the product leaves the factory. Through this data-closed-loop self-consistent judgment mechanism, the long-term operational reliability of precision systems under temperature fluctuations and vibration loads is significantly improved.

[0038] 2. By deploying acoustic sensors on the outer wall of the threaded joint and combining them with internal pressure sensors, synchronous acquisition of multi-source signals is achieved. This layout can establish correlation clues from two physical dimensions: solid conduction and fluid dynamics. It avoids the limitations of traditional single-sensor solutions in terms of signal distortion under complex working conditions. Synchronous acquisition ensures strict alignment of the acoustic wave penetration characteristics and minor pressure disturbances on the time axis, providing high-precision raw data support for subsequent analysis of the fluid-structure interaction state. This spatiotemporal collaborative sensing method can keenly capture transient changes in the microscopic physical state within the thread gap, greatly enhancing the system's ability to suppress environmental noise and random pulse interference. It ensures the integrity and authenticity of information in the feature extraction stage and lays a solid data foundation for identifying false pressure holding states caused by uncured adhesive or micro-bubbles. This multi-dimensional sensing strategy significantly enhances the robustness of the judgment system in complex industrial environments, ensures the integrity and authenticity of information in the original feature extraction stage, and achieves comprehensive analysis of the physical properties of the connection interface.

[0039] 3. By reconstructing the true unfolded length of the helical microchannel based on the thread geometry and solving for the acoustic retardation attenuation coefficient, this step fully respects the actual physical path of sound waves and fluids climbing within the threaded pair. It overcomes the calculation errors caused by simplifying the helical structure to a linear model, providing a clear spatial normalization basis for the assessment of acoustic energy loss. This refined modeling method ensures that the attenuation index objectively reflects the mesh tightness per unit length, effectively eliminating the problem of inconsistent judgment criteria caused by differences in thread diameter or number of turns. The acoustic retardation coefficient, as a key indicator characterizing the continuity of interface contact, can accurately identify whether there are air gaps or discontinuities between the threaded contact surfaces, achieving a quantitative and standardized description of the physical quality of the connection. This enhances the versatility of the solution for parts of different specifications. By deeply coupling macroscopic geometric features with the acoustic attenuation mechanism, an objective physical evaluation index independent of empirical data is constructed, providing a reliable geometric constraint basis for subsequently distinguishing between real metal contact and the illusion of gas-liquid blockage.

[0040] 4. By combining thread profile features to extract morphological compensation factors and calculate the maximum tolerance void volume, this design introduces geometric constraints that conform to engineering manufacturing realities into the judgment logic. The morphological compensation factor corrects the energy deviation of sound waves during reflection on the inclined plane, ensuring fairness for threaded joints with different thread profile half-angles under the same evaluation scale. The definition of the maximum tolerance void volume sets a physical benchmark upper limit for evaluating the sealing state. By clarifying the reasonable void ratio within the tolerance range of this specification, the algorithm can effectively distinguish between normal machining redundancy and abnormal leakage channels. This compensation mechanism based on design specifications makes the judgment results both conform to physical laws and engineering standards, greatly improving the system's tolerance to manufacturing deviations, achieving scientific quantification of the degree of damage to sealing performance, and enhancing the reliability of the algorithm in precision testing scenarios. By introducing analytical correction of geometric morphology, a deep correction of sound pressure characteristic quantities is achieved, making the final sealing index more closely resemble the actual contact mechanics.

[0041] 5. The fluid-structure interaction (FSI) sealing impedance is calculated by coupling the spatial acoustic attenuation coefficient with the micro-leakage volume equivalent. This core calculation step achieves cross-dimensional integration of solid contact characteristics and fluid dynamics features. The FSI sealing impedance can reflect the overall density of the physical connection of the joint. When there are bubbles or uncured adhesive at the interface, the increase in acoustic resistance and the increase in micro-leakage volume will produce superimposed feedback, causing a significant shift in the impedance index. This dual verification mechanism can effectively remove complex illusions that cannot be detected by single-dimensional monitoring. For example, when the pressure is stable due to micro-chamber blockage, the acoustic index can reveal the lack of physical engagement, achieving a deep analysis of the essence of sealing. By constructing an evaluation model that reflects the essence of fluid-structure interaction, a judgment basis with unique physical determinism is provided, significantly enhancing the system's ability to distinguish the sealing state during transient windows. Data closure and self-consistency within the algorithm are achieved, ensuring that the judgment conclusion does not depend on any external reference data. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the basic process of the present invention. Detailed Implementation

[0043] 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, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0044] Example 1, refer to Figure 1 A method for rapid determination of thread seals based on intelligent sensors, comprising:

[0045] The acoustic excitation signal and the corresponding acoustic reception signal set outside the threaded joint are collected synchronously, as well as the transient pressure signal set inside the fluid cavity of the thread.

[0046] The received acoustic signal is integrated in the time domain within a time window to extract the total penetrating acoustic energy, and the transient pressure signal is stripped of its initial static base value to obtain a dynamic pressure micro-fluctuation sequence.

[0047] The actual unfolded length of the spiral microchannel is calculated based on the macroscopic geometric parameters of the thread, and the spatial acoustic retardation attenuation coefficient is calculated by combining the initial excitation energy and the total penetrating acoustic energy.

[0048] The absolute rate of change of the dynamic pressure micro-fluctuation sequence is extracted and integrated in the time domain to obtain the cumulative dynamic pressure relief micro-perturbation.

[0049] By utilizing the initial volume of the internal fluid cavity and the inherent compressibility of the fluid, the accumulated dynamic pressure relief perturbation is converted into the equivalent of structural micro-leakage volume.

[0050] The morphological compensation factor is extracted by combining the thread profile features. The maximum tolerance gap volume is calculated based on the tolerance gap area and the actual unfolded length. Then, the fluid-structure coupling sealing impedance is calculated by combining the acoustic hysteresis attenuation coefficient and the micro-leakage volume equivalent.

[0051] Based on the inherent physical properties of the thread material, the theoretical reference impedance under ideal conditions is derived, and an adaptive dynamic judgment threshold is generated by combining the geometric tolerance distribution of the thread surface.

[0052] The real-time calculated fluid-structure interaction sealing impedance is compared with the adaptive dynamic judgment threshold, and the final thread sealing status judgment result is output based on the comparison result.

[0053] The synchronous acquisition of acoustic excitation signals and corresponding acoustic reception signals located outside the threaded joint, as well as transient pressure signals located inside the fluid cavity of the thread, specifically includes:

[0054] A piezoelectric acoustic wave exciter is deployed on the outer wall of the male end of the threaded connector; an acoustic emission receiving sensor is deployed on the outer wall of the female end; a high-frequency dynamic pressure sensor is deployed in the internal fluid cavity of the threaded connection; the initial amplitude of the standard excitation signal emitted by the exciter and the total length of the sampling time window are acquired; within the sampling time window, the time-series acoustic envelope signal acquired by the acoustic emission receiving sensor and the time-series transient pressure signal acquired by the pressure sensor are acquired synchronously; known parameters are acquired, including the standard thread pitch, nominal thread diameter, actual number of turns engaged, thread profile half angle, standard tolerance clearance cross-sectional area, initial volume of the internal fluid cavity, fluid bulk modulus, density of the thread metal material, and standard propagation speed of sound waves in the material.

[0055] The step of performing time-domain integration on the received acoustic signal within a time window to extract the total penetrating acoustic energy, and stripping the transient pressure signal of its initial static baseline to obtain a dynamic pressure micro-fluctuation sequence, specifically includes:

[0056] The square value of the acquired time-series acoustic envelope signal is integrated in the time domain within the sampling time window, and the integration result is used as the total received acoustic energy penetrating the thread engagement zone within the entire sampling time window.

[0057] By subtracting the static internal pressure baseline value acquired at the initial moment from the acquired time-series transient pressure signal, a dynamic pressure micro-fluidity sequence is obtained to characterize the fluid's micro-escape response.

[0058] The calculation of the actual unfolded length of the helical microchannel based on the macroscopic geometric parameters of the thread, and the calculation of the spatial acoustic retardation attenuation coefficient by combining the initial excitation energy and the total penetrating acoustic energy, specifically includes:

[0059] The circumference is calculated based on the nominal diameter of the thread. The unfolded length of a single turn of the helix is ​​determined by the calculated circumference and the standard thread pitch. The unfolded length of the single turn of the helix is ​​multiplied by the actual number of turns to obtain the true unfolded length of the helical microchannel through which the sound waves and fluid actually pass.

[0060] Calculate the product of the square of the initial amplitude of the standard excitation signal and the total length of the sampling time window; solve for the natural logarithm of the ratio of this product to the total received acoustic energy; divide the value of this natural logarithm by the actual unfolded length of the spiral microchannel to calculate the path-normalized spatial acoustic attenuation coefficient.

[0061] The step of extracting the absolute rate of change from the dynamic pressure micro-fluctuation sequence and performing time-domain integration to obtain the cumulative dynamic pressure relief micro-perturbation specifically includes:

[0062] Calculate the derivative of the dynamic pressure micro-fluctuation sequence with respect to time; take the absolute value of the derivative result.

[0063] Within the sampling time window, the derivative result after taking the absolute value is integrated in the time domain to extract the cumulative dynamic pressure relief perturbation.

[0064] The method of utilizing the initial volume of the internal fluid cavity and the inherent compressibility properties of the fluid to convert the accumulated dynamic pressure relief perturbation into the equivalent of structural micro-leakage volume specifically includes:

[0065] Calculate the product of the cumulative dynamic pressure relief perturbation and the initial volume of the internal fluid cavity; divide the product by the fluid volume elastic modulus to convert the pressure perturbation into the equivalent of the structural microleakage volume.

[0066] The method involves extracting a morphological compensation factor based on thread profile features, calculating the maximum tolerance gap volume based on the tolerance gap area and the actual unfolded length, and then calculating the fluid-structure interaction sealing impedance by combining the acoustic hysteresis attenuation coefficient and the micro-leakage volume equivalent. Specifically, this includes:

[0067] Calculate the cosine value of the thread profile half angle; calculate the reciprocal of the above cosine value as the morphological compensation factor for the sound wave transmission of the thread profile inclination angle.

[0068] Multiply the standard tolerance clearance cross-sectional area by the actual unfolded length of the spiral microchannel to calculate the theoretically maximum allowable tolerance micro-cell void volume at that screw length;

[0069] Calculate the ratio of the structural microleak volume equivalent to the maximum tolerance micro-cell volume; multiply the spatial acoustic retardation attenuation coefficient by the morphological compensation factor to obtain the first product; add one to the ratio to obtain the divisor; divide the first product by the divisor to calculate the fluid-structure interaction sealing impedance characteristic quantity characterizing the true sealing state of the joint.

[0070] The process of deriving the theoretical reference impedance under ideal conditions based on the inherent physical properties of the thread material, and generating an adaptive dynamic judgment threshold by combining the geometric tolerance distribution of the thread surface, specifically includes:

[0071] Multiply the density of the threaded metal material, the standard propagation speed of sound in the material, and the morphological compensation factor; divide the result of the above three multiplications by the actual unfolded length of the helical microchannel to calculate the pure analytical theoretical acoustic emission reference impedance under absolutely ideal contact conditions;

[0072] Calculate the product of the nominal diameter of the thread, the standard pitch of the thread, and pi; calculate the ratio of the standard tolerance clearance cross-sectional area to the product of the above three; subtract the above ratio from one to obtain the tolerance factor; multiply the theoretical acoustic emission reference impedance by the tolerance factor to give the reference impedance an adaptive dynamic structural tolerance margin, and generate the final adaptive dynamic judgment threshold.

[0073] The process of comparing the real-time calculated fluid-structure interaction sealing impedance with the adaptive dynamic judgment threshold, and outputting the final thread sealing status judgment result based on the comparison result, specifically includes:

[0074] Subtract the adaptive dynamic judgment threshold from the calculated fluid-structure interaction sealing impedance; take the mathematical sign function value of the result after subtraction to obtain the final sealing judgment indicator variable; when the final sealing judgment indicator variable is equal to positive one, the judgment result is that the thread engagement is sufficient and there is no false pressure, which is a true safe seal; when the final sealing judgment indicator variable is equal to negative one, the judgment result is that there are transient sealing illusions caused by incomplete air bubbles or glue displacement inside.

[0075] Example 2: A method for rapid determination of thread seals based on intelligent sensors, further comprising:

[0076] The synchronous acquisition of acoustic excitation signals and corresponding acoustic reception signals located outside the threaded joint, as well as transient pressure signals located inside the fluid cavity of the thread, specifically includes:

[0077] A piezoelectric acoustic wave exciter is deployed on the outer wall of the male end of the threaded connector, an acoustic emission receiving sensor is deployed on the outer wall of the female end, and a high-frequency dynamic pressure sensor is deployed in the internal fluid cavity of the threaded connection. The following data is measured and acquired: the initial amplitude of the standard excitation signal emitted by the exciter. and total sampling time window length ; within the time window Within, the time-series acoustic envelope signal acquired by the acoustic emission and reception sensor is synchronously collected. and the time-series transient pressure signal acquired by the pressure sensor. ;

[0078] Obtain known parameters: standard thread pitch Thread nominal diameter Actual number of turns Thread tooth profile half angle Standard tolerance clearance cross-sectional area Initial volume of internal fluid cavity Fluid bulk elastic modulus Density of threaded metal materials Standard speed of sound propagation in this material .

[0079] By deploying acoustic sensors on the outer wall of the threaded joint and combining them with internal pressure sensors, synchronous acquisition of multi-source signals is achieved. This layout establishes correlation clues from two physical dimensions: solid conduction and fluid dynamics. It avoids the limitations of traditional single-sensor solutions in terms of signal distortion under complex working conditions. Synchronous acquisition ensures strict alignment of acoustic wave penetration characteristics and minor pressure disturbances on the time axis, providing high-precision raw data support for subsequent analysis of fluid-structure interaction. This spatiotemporal collaborative sensing method can keenly capture transient changes in the microscopic physical state within the thread gap, greatly enhancing the system's ability to suppress environmental noise and random pulse interference. It ensures the integrity and authenticity of information in the feature extraction stage and lays a solid data foundation for identifying false pressure holding states caused by uncured adhesive or micro-bubbles. This multi-dimensional sensing strategy significantly enhances the robustness of the judgment system in complex industrial environments, ensures the integrity and authenticity of information in the original feature extraction stage, and achieves comprehensive analysis of the physical properties of the connection interface.

[0080] The step of performing time-domain integration on the received acoustic signal within a time window to extract the total penetrating acoustic energy, and stripping the transient pressure signal of its initial static baseline to obtain a dynamic pressure micro-fluctuation sequence, specifically includes:

[0081] The total received acoustic energy penetrating the thread engagement zone within the entire sampling time window is calculated using the following formula:

[0082] In the formula, The total amount of sound wave energy received within the time window; The acquired time-series acoustic envelope signal; This is the total length of the sampling time window;

[0083] The dynamic pressure micro-fluid fluctuation sequence used to characterize the small escape response of the fluid is separated using the following formula:

[0084] In the formula, It is a dynamic pressure micro-fluctuation sequence; For the acquisition of time-series transient pressure signals; In order to be in The initial static internal pressure baseline value acquired at each moment.

[0085] The calculation of the actual unfolded length of the helical microchannel based on the macroscopic geometric parameters of the thread, and the calculation of the spatial acoustic retardation attenuation coefficient by combining the initial excitation energy and the total penetrating acoustic energy, specifically includes:

[0086] The actual unfolded length of the spiral microchannel through which the sound wave and fluid actually pass can be calculated using the following formula:

[0087] In the formula, This represents the actual unfolded length of the spiral microchannel; This represents the actual number of turns. Pi; This refers to the nominal diameter of the thread. This refers to the standard thread pitch.

[0088] The path-normalized spatial acoustic attenuation coefficient is calculated using the following formula:

[0089] In the formula, The spatial acoustic attenuation coefficient; This represents the actual unfolded length of the spiral microchannel; The initial amplitude of the standard excitation signal; This is the total length of the sampling time window; The total amount of sound wave energy received within the time window.

[0090] By reconstructing the true unfolded length of the helical microchannel based on the thread geometry and solving for the acoustic hysteresis attenuation coefficient, this step fully respects the actual physical path of sound waves and fluids climbing within the threaded pair. It overcomes the calculation errors caused by simplifying the helical structure to a linear model, providing a clear spatial normalization basis for the assessment of acoustic energy loss. This refined modeling method ensures that the attenuation index objectively reflects the engagement tightness per unit length, effectively eliminating the problem of inconsistent judgment criteria caused by differences in thread diameter or number of turns. The acoustic hysteresis coefficient, as a key indicator characterizing the continuity of interface contact, can accurately identify whether there are air gaps or discontinuities between the threaded contact surfaces, achieving a quantitative and standardized description of the physical quality of the connection. It enhances the versatility of the solution for parts of different specifications. By deeply coupling macroscopic geometric features with the acoustic attenuation mechanism, it constructs an objective physical evaluation index that does not rely on empirical data, providing a reliable geometric constraint basis for subsequently distinguishing between real metal contact and the illusion of gas-liquid blockage.

[0091] The step of extracting the absolute rate of change from the dynamic pressure micro-fluctuation sequence and performing time-domain integration to obtain the cumulative dynamic pressure relief micro-perturbation specifically includes:

[0092] The cumulative dynamic pressure relief perturbation is extracted by performing differentiation and integration operations on the pressure micro-fluctuation signal using the following formula:

[0093] In the formula, To accumulate dynamic pressure relief perturbations; It is a dynamic pressure micro-fluctuation sequence; This represents the total length of the sampling time window.

[0094] The method of utilizing the initial volume of the internal fluid cavity and the inherent compressibility properties of the fluid to convert the accumulated dynamic pressure relief perturbation into the equivalent of structural micro-leakage volume specifically includes:

[0095] The pressure perturbation is converted into the structural microleakage volume equivalent using the following formula:

[0096] In the formula, The equivalent of structural microleakage volume; To accumulate dynamic pressure relief perturbations; This represents the initial volume of the internal fluid cavity; This is the bulk elastic modulus of the fluid.

[0097] The method involves extracting a morphological compensation factor based on thread profile features, calculating the maximum tolerance gap volume based on the tolerance gap area and the actual unfolded length, and then calculating the fluid-structure interaction sealing impedance by combining the acoustic hysteresis attenuation coefficient and the micro-leakage volume equivalent. Specifically, this includes:

[0098] The morphological compensation factor for sound wave transmission due to thread profile inclination angle is calculated using the following formula:

[0099] In the formula, It is a morphological compensation factor; It is the thread profile half angle.

[0100] The theoretically permissible maximum tolerance micro-cell void volume at this engagement length is calculated using the following formula:

[0101] In the formula, The maximum tolerance micro-cell volume; The standard tolerance clearance cross-sectional area; This represents the actual unfolded length of the spiral microchannel.

[0102] The core quantity characterizing the fluid-structure interaction sealing impedance of the joint, representing its true sealing state, is calculated using the following formula:

[0103] In the formula, This refers to the characteristic quantity of the fluid-structure interaction sealing impedance. The spatial acoustic attenuation coefficient; It is a morphological compensation factor; The equivalent of structural microleakage volume; This represents the maximum tolerance micro-chamber volume.

[0104] By combining thread profile features to extract morphological compensation factors and calculating the maximum tolerance void volume, this design introduces geometric constraints that conform to engineering manufacturing realities into the judgment logic. The morphological compensation factor corrects the energy deviation of sound waves during reflection on the inclined plane, ensuring fairness for threaded joints with different thread profile half-angles under the same evaluation scale. The definition of the maximum tolerance void volume sets a physical benchmark upper limit for evaluating the sealing state. By clarifying the reasonable void ratio within the tolerance range of this specification, the algorithm can effectively distinguish between normal machining redundancy and abnormal leakage channels. This compensation mechanism based on design specifications makes the judgment results both conform to physical laws and engineering standards, greatly improving the system's tolerance to manufacturing deviations, achieving scientific quantification of the degree of sealing performance damage, and enhancing the reliability of the algorithm in precision testing scenarios. By introducing analytical correction of geometric morphology, a deep correction of sound pressure characteristics is achieved, making the final sealing index more closely resemble the actual contact mechanics.

[0105] The process of deriving the theoretical reference impedance under ideal conditions based on the inherent physical properties of the thread material, and generating an adaptive dynamic judgment threshold by combining the geometric tolerance distribution of the thread surface, specifically includes:

[0106] The purely analytical theoretical acoustic emission reference impedance under absolutely ideal contact conditions is calculated using the following formula:

[0107] In the formula, The theoretical acoustic emission reference impedance; The density of the threaded metal material; The standard velocity of sound propagation in the material; It is a morphological compensation factor; This represents the actual unfolded length of the spiral microchannel.

[0108] The final decision threshold is generated by assigning an adaptive dynamic structural tolerance margin to the reference impedance using the following formula:

[0109] In the formula, For adaptive dynamic threshold determination; The theoretical acoustic emission reference impedance; The standard tolerance clearance cross-sectional area; This refers to the nominal diameter of the thread. This refers to the standard thread pitch.

[0110] The process of comparing the real-time calculated fluid-structure interaction sealing impedance with the adaptive dynamic judgment threshold, and outputting the final thread sealing status judgment result based on the comparison result, specifically includes:

[0111] The final result is output by comparing the real-time calculated fluid-structure interaction sealing impedance with the adaptive judgment threshold, as shown in the following formula:

[0112] In the formula, This serves as an indicator variable for the final sealing determination. For mathematical symbolic functions; This refers to the characteristic quantity of the fluid-structure interaction sealing impedance. For adaptive dynamic threshold determination;

[0113] when When the thread engagement is deemed sufficient and without false pressure, it is considered a true safety seal; when At that time, it was determined that there were transient sealing illusions caused by incomplete removal of air bubbles or displacement of adhesive inside.

[0114] The fluid-structure interaction (FSI) sealing impedance is calculated by coupling the spatial acoustic attenuation coefficient with the microleak volume equivalent. This core calculation step achieves cross-dimensional fusion of solid contact characteristics and fluid dynamics features. The FSI sealing impedance can reflect the overall density of the physical connection of the joint. When there are bubbles or uncured adhesive at the interface, the increase in acoustic resistance and the increase in microleak volume will produce superimposed feedback, causing a significant shift in the impedance index. This dual verification mechanism can effectively eliminate complex artifacts that cannot be detected by single-dimensional monitoring. For example, when the pressure is stable due to micro-chamber blockage, the acoustic index can reveal the lack of physical engagement, achieving a deep analysis of the essence of sealing. By constructing an evaluation model that reflects the essence of fluid-structure interaction, a judgment criterion with unique physical determinism is provided, significantly enhancing the system's ability to distinguish the sealing state during transient windows. The algorithm achieves data closure and self-consistency, ensuring that the judgment conclusion does not depend on any external reference data.

[0115] This solution is designed for specific industrial rapid testing environments involving threaded connections during the initial engagement stage or before the application of liquid sealant for curing. In this environment, residual microbubbles or uncured sealant in the thread gap can easily create unstable "transient sealing artifacts," posing a serious risk of failure to traditional methods relying solely on pressure drop for judgment. This solution employs an acoustic-pressure fusion architecture to leverage the extremely high sensitivity of acoustic emission waves to the solid engagement state, combined with the ability of a high-frequency dynamic pressure sensor to capture fluid disturbances, thereby physically dismantling and penetrating this transient equilibrium state. Its unique and beneficial effect lies in reconstructing the helical propagation path and calculating fluid-structure interaction. The sealing impedance method digitally links the microscopic tooth engagement quality with the macroscopic pressure relief volume, thereby automatically deriving the absolute threshold for judgment based solely on the material properties and geometric tolerances of the parts without relying on any human experience or requiring massive sample training. This makes the solution highly adaptable and accurate when facing high-turnover automated production lines, and can eliminate "false seal" products that, although temporarily non-leaking, have structural defects within a very short window before the product leaves the factory. Through this self-consistent judgment mechanism with closed-loop data, the long-term operational reliability of precision systems under temperature fluctuations and vibration loads is significantly improved.

[0116] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0117] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for rapid determination of thread seals based on intelligent sensors, characterized in that, include: The acoustic excitation signal and the corresponding acoustic reception signal set outside the threaded joint are collected synchronously, as well as the transient pressure signal set inside the fluid cavity of the thread. The received acoustic signal is integrated in the time domain within a time window to extract the total penetrating acoustic energy, and the transient pressure signal is stripped of its initial static base value to obtain a dynamic pressure micro-fluctuation sequence. The actual unfolded length of the spiral microchannel is calculated based on the macroscopic geometric parameters of the thread, and the spatial acoustic retardation attenuation coefficient is calculated by combining the initial excitation energy and the total penetrating acoustic energy. The absolute rate of change of the dynamic pressure micro-fluctuation sequence is extracted and integrated in the time domain to obtain the cumulative dynamic pressure relief micro-perturbation. By utilizing the initial volume of the internal fluid cavity and the inherent compressibility of the fluid, the accumulated dynamic pressure relief perturbation is converted into the equivalent of structural micro-leakage volume. The morphological compensation factor is extracted by combining the thread profile features. The maximum tolerance gap volume is calculated based on the tolerance gap area and the actual unfolded length. Then, the fluid-structure coupling sealing impedance is calculated by combining the acoustic hysteresis attenuation coefficient and the micro-leakage volume equivalent. Based on the inherent physical properties of the thread material, the theoretical reference impedance under ideal conditions is derived, and an adaptive dynamic judgment threshold is generated by combining the geometric tolerance distribution of the thread surface. The real-time calculated fluid-structure interaction sealing impedance is compared with the adaptive dynamic judgment threshold, and the final thread sealing status judgment result is output based on the comparison result.

2. The method for rapid determination of thread seal based on intelligent sensors according to claim 1, characterized in that, The synchronous acquisition of acoustic excitation signals and corresponding acoustic reception signals located outside the threaded joint, as well as transient pressure signals located inside the fluid cavity of the thread, specifically includes: A piezoelectric acoustic wave exciter is deployed on the outer wall of the male end of the threaded connector; an acoustic emission receiving sensor is deployed on the outer wall of the female end; a high-frequency dynamic pressure sensor is deployed in the internal fluid cavity of the threaded connection; the initial amplitude of the standard excitation signal emitted by the exciter and the total length of the sampling time window are acquired; within the sampling time window, the time-series acoustic wave envelope signal acquired by the acoustic emission receiving sensor and the time-series transient pressure signal acquired by the pressure sensor are acquired synchronously; known parameters are acquired, including the standard thread pitch, nominal thread diameter, actual number of turns engaged, thread profile half angle, standard tolerance clearance cross-sectional area, initial volume of the internal fluid cavity, fluid bulk modulus, density of the thread metal material, and standard propagation speed of sound waves in the material.

3. The method for rapid determination of thread seals based on intelligent sensors according to claim 1, characterized in that, The step of performing time-domain integration on the received acoustic signal within a time window to extract the total penetrating acoustic energy, and stripping the transient pressure signal of its initial static baseline to obtain a dynamic pressure micro-fluctuation sequence, specifically includes: The square value of the acquired time-series acoustic envelope signal is integrated in the time domain within the sampling time window, and the integration result is used as the total received acoustic energy penetrating the thread engagement zone within the entire sampling time window. By subtracting the static internal pressure baseline value acquired at the initial moment from the acquired time-series transient pressure signal, a dynamic pressure micro-fluidity sequence is obtained to characterize the fluid's micro-escape response.

4. The method for rapid determination of thread seals based on intelligent sensors according to claim 1, characterized in that, The calculation of the actual unfolded length of the helical microchannel based on the macroscopic geometric parameters of the thread, and the calculation of the spatial acoustic retardation attenuation coefficient by combining the initial excitation energy and the total penetrating acoustic energy, specifically includes: The circumference is calculated based on the nominal diameter of the thread. The unfolded length of a single turn of the helix is ​​determined by the calculated circumference and the standard thread pitch. The unfolded length of the single turn of the helix is ​​multiplied by the actual number of turns to obtain the true unfolded length of the helical microchannel through which the sound waves and fluid actually pass. Calculate the product of the square of the initial amplitude of the standard excitation signal and the total length of the sampling time window; solve for the natural logarithm of the ratio of this product to the total received acoustic energy; divide the value of this natural logarithm by the actual unfolded length of the spiral microchannel to calculate the path-normalized spatial acoustic attenuation coefficient.

5. The method for rapid determination of thread seals based on intelligent sensors according to claim 1, characterized in that, The step of extracting the absolute rate of change from the dynamic pressure micro-fluctuation sequence and performing time-domain integration to obtain the cumulative dynamic pressure relief micro-perturbation specifically includes: Calculate the derivative of the dynamic pressure micro-fluctuation sequence with respect to time; take the absolute value of the derivative result. Within the sampling time window, time-domain integration is performed on the derivative result after taking the absolute value to extract the cumulative dynamic pressure relief perturbation.

6. The method for rapid determination of thread seals based on intelligent sensors according to claim 1, characterized in that, The method of utilizing the initial volume of the internal fluid cavity and the inherent compressibility properties of the fluid to convert the accumulated dynamic pressure relief perturbation into the equivalent of structural micro-leakage volume specifically includes: Calculate the product of the cumulative dynamic pressure relief perturbation and the initial volume of the internal fluid cavity; divide the product by the fluid volume elastic modulus to convert the pressure perturbation into the equivalent of the structural microleakage volume.

7. The method for rapid determination of thread seals based on intelligent sensors according to claim 1, characterized in that, The method involves extracting a morphological compensation factor based on thread profile features, calculating the maximum tolerance gap volume based on the tolerance gap area and the actual unfolded length, and then calculating the fluid-structure interaction sealing impedance by combining the acoustic hysteresis attenuation coefficient and the micro-leakage volume equivalent. Specifically, this includes: Calculate the cosine value of the thread profile half angle; calculate the reciprocal of the above cosine value as the morphological compensation factor for the sound wave transmission of the thread profile inclination angle. Multiply the standard tolerance clearance cross-sectional area by the actual unfolded length of the spiral microchannel to calculate the theoretically maximum allowable tolerance micro-cell void volume at that screw length; Calculate the ratio of the structural microleak volume equivalent to the maximum tolerance micro-cell volume; multiply the spatial acoustic retardation attenuation coefficient by the morphological compensation factor to obtain the first product; add one to the ratio to obtain the divisor; divide the first product by the divisor to calculate the fluid-structure interaction sealing impedance characteristic quantity characterizing the true sealing state of the joint.

8. The method for rapid determination of thread seals based on intelligent sensors according to claim 1, characterized in that, The process of deriving the theoretical reference impedance under ideal conditions based on the inherent physical properties of the thread material, and generating an adaptive dynamic judgment threshold by combining the geometric tolerance distribution of the thread surface, specifically includes: Multiply the density of the threaded metal material, the standard propagation speed of sound in the material, and the morphological compensation factor; divide the result of the above three multiplications by the actual unfolded length of the helical microchannel to calculate the pure analytical theoretical acoustic emission reference impedance under absolutely ideal contact conditions; Calculate the product of the nominal diameter of the thread, the standard pitch of the thread, and pi; calculate the ratio of the standard tolerance clearance cross-sectional area to the product of the above three; subtract the above ratio from one to obtain the tolerance factor; multiply the theoretical acoustic emission reference impedance by the tolerance factor to give the reference impedance an adaptive dynamic structural tolerance margin, and generate the final adaptive dynamic judgment threshold.

9. The method for rapid determination of thread seals based on intelligent sensors according to claim 1, characterized in that, The process of comparing the real-time calculated fluid-structure interaction sealing impedance with the adaptive dynamic judgment threshold, and outputting the final thread sealing status judgment result based on the comparison result, specifically includes: Subtract the adaptive dynamic judgment threshold from the calculated fluid-structure interaction sealing impedance; take the mathematical sign function value of the result after subtraction to obtain the final sealing judgment indicator variable; when the final sealing judgment indicator variable is equal to positive one, the judgment result is that the thread engagement is sufficient and there is no false pressure, which is a true safe seal; when the final sealing judgment indicator variable is equal to negative one, the judgment result is that there are transient sealing illusions caused by incomplete air bubbles or glue displacement inside.

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