Optical coherence tomography detection method of aero-engine thermal growth oxide

Abstract

The invention discloses an optical coherence tomography detection method for aero-engine thermal growth oxides, and relates to the field of optical detection. The method comprises the following steps: acquiring interference signals of a reference light field and a sample scattering light field, and performing adaptive polarization state compensation on the interference signals based on a dynamic polarization matching factor to obtain compensated interference signals; anisotropic filtering is carried out on the compensation interference signal, oxide layer columnar crystal structure features are separated, and a filtering signal is obtained; performing time-frequency joint analysis on the filtering signal, optimizing a time-frequency transformation kernel parameter by using an adaptive window width adjustment factor, and extracting oxide layer thickness and frequency band energy distribution; and fusing the columnar crystal structure characteristics and the frequency band energy distribution, constructing a cross-scale thermodynamic inversion model, and outputting a prediction result of the residual life of the thermal growth oxide layer of the engine. By introducing polarization compensation, frequency domain analysis optimization and a multi-field coupling inversion model, the imaging definition, the thickness extraction precision and the residual life prediction capability of the thermal growth oxide layer are remarkably improved.

Description

Technical Field

[0001] The present invention relates to the field of optical detection, and specifically to an optical coherence tomography detection method for thermally grown oxides of aeroengines. Background Art

[0002] During the service process of aeroengines, due to being in harsh working conditions such as high temperature, high pressure, high-speed airflow, and oxidizing atmosphere for a long time, thermal growth oxidation often occurs on the surfaces of their hot-end components. The continuous growth of the oxide layer will cause the deterioration of the material microstructure, reduce its thermal barrier performance and mechanical strength, and is a key factor leading to the attenuation of service life and even the failure of components. Therefore, accurately detecting the geometric characteristics and microstructure evolution of thermally grown oxides is of great significance for ensuring the service safety of engines and carrying out life prediction and evaluation.

[0003] As a high-spatial-resolution and non-contact three-dimensional imaging technology, optical coherence tomography has shown great potential in material microstructure detection in recent years. However, when standard OCT imaging faces complex multi-scattering media such as thermally grown oxide layers, the signal quality often decreases due to uneven light scattering and polarization perturbation, which further limits its ability to resolve microscopic structure features and the accuracy of thickness changes. In addition, existing OCT detection methods have not combined crystal structure information for physical modeling and life prediction, and it is difficult to meet the accurate evaluation requirements for the evolution behavior of thermally grown oxide layers in the complex service environment of aeroengines.

[0004] Therefore, there is an urgent need for an OCT detection method for thermally grown oxides that integrates polarization compensation, adaptive filtering, frequency-domain analysis, and cross-scale modeling to improve the microstructure recognition ability of thermally grown oxide layers, enhance the modeling accuracy of their thickness and thermodynamic evolution laws, and achieve an organic integration of non-destruction, high resolution, and remaining life prediction. Summary of the Invention

[0005] Based on the above-mentioned disadvantages of the prior art, the purpose of the present invention is to provide an optical coherence tomography detection method for thermally grown oxides of aeroengines to solve the above technical problems.

[0006] To achieve the above purpose, the present invention provides the following technical solution: An optical coherence tomography detection method for thermally grown oxides of aeroengines, including: S1: Collect the interference signal of the reference light field and the sample scattered light field, and perform adaptive polarization state compensation on the interference signal based on the dynamic polarization matching factor to obtain the compensated interference signal; S2: Perform anisotropic filtering on the compensated interference signal, retain the signal discontinuity at the columnar crystal grain boundaries by constraining the grain boundary discontinuity index, and separate the columnar crystal structure features of the oxide layer to obtain the filtered signal; S3: Perform time-frequency joint analysis on the filtered signal, optimize the time-frequency transformation kernel parameters using the adaptive window width adjustment factor, and extract the oxide layer thickness and frequency band energy distribution. S4: Integrate the columnar crystal structure characteristics and the frequency band energy distribution, construct a cross-scale thermodynamic inversion model, and output the prediction result of the remaining life of the oxide layer of the engine thermal growth oxide.

[0007] The present invention is further configured to collect the interference signal of the reference light field and the sample scattered light field, analyze the interference signal, extract the phase information of the analyzed signal, calculate the dynamic polarization matching factor, construct a sparse regularization optimization problem, dynamically adjust the polarization compensation matrix, and use the updated polarization compensation matrix to correct the polarization state of the interference signal to obtain the compensated interference signal.

[0008] The present invention is further configured that the dynamic polarization matching factor is dynamically updated through the phase gradient tensor product and the sparsity constraint of the polarization compensation matrix, and its expression is: , where is the dynamic polarization matching factor, is the spatial phase gradient, is the phase distortion field, is the Frobenius norm, is the Jones matrix is the trace of is the Jones matrix is the conjugate transpose matrix of is the adjustment parameter.

[0009] The present invention is further configured to construct a depth-resolved diffusion model based on the anisotropic dielectric tensor of the oxide layer columnar crystal structure, quantify the mutation intensity of the dielectric constant through the grain boundary discontinuity index and weighted constraint to retain the signal discontinuity in the filtering process, and use an iterative algorithm to solve the joint optimization problem of the anisotropic diffusion equation and the grain boundary constraint to separate the oxide layer columnar crystal structure characteristics and obtain the filtered signal.

[0010] The present invention is further configured that the grain boundary discontinuity index is calculated through the normalized ratio of the dielectric constant mutation to the grain size, and its expression is: , where is the grain boundary discontinuity index, and are the dielectric constants on both sides of the grain boundary, is the depth position, is the average grain diameter, is the system axial resolution, represents the second moment of the dielectric constant component and is defined as: , where is the total number of sampling points in the depth direction of the oxide layer, is the depth position.

[0011] The present invention is further configured such that the time-frequency joint analysis of the filtered signal includes: Optimizing the time-frequency transform kernel parameters using an adaptive window width adjustment factor; Generating an optimal time-frequency distribution by maximizing the weighted fitness function of the band energy and the signal-to-noise ratio through a genetic algorithm; Nonlinearly compressing the band energy based on the hyperbolic tangent function, combining the coefficients calibrated by the Arrhenius equation of oxidation kinetics for weighted summation, and mapping to the physical thickness interval through a sigmoid function to extract the oxide layer thickness and the band energy distribution.

[0012] The present invention is further configured such that the adaptive window width adjustment factor is calculated by the elastic coefficient of the window scale parameter with respect to the band energy and the frequency shift cut-off matching degree, and its expression is: , where is the adaptive window width adjustment factor, is the total number of frequency bands, is the band energy of the is the window scale parameter, Calculating the band energy elastic coefficient, Calculating the frequency shift cut-off matching degree, is the frequency band translation parameter of the is the cut-off frequency, .

[0013] The present invention is further configured such that the construction of the cross-scale thermodynamics inversion model includes: Fusing the columnar crystal structure characteristics and the band energy distribution to establish a multi-field coupling constitutive equation, where the oxidation activation energy is corrected by the grain boundary discontinuity index and the stress index is nonlinearly modulated by the band energy; Solving the parameters of the oxide layer growth rate equation based on the Bayesian Markov chain Monte Carlo inversion method, and quantifying the uncertainty of the remaining life prediction by combining Monte Carlo simulation; Dynamically feedbacking the inversion parameters to the preprocessing step to form a closed-loop optimization of detection-modeling-prediction.

[0014] The present invention is further configured such that the cross-scale thermodynamics inversion model corrects the oxidation activation energy through the grain boundary discontinuity index, and its expression is: , where is the maximum grain boundary discontinuity index, is the dynamic polarization matching factor, is the corrected value of the oxidation activation energy, is the reference oxidation activation energy, is the Boltzmann constant, is the absolute temperature, is the adjustment coefficient.

[0015] The present invention is further configured such that the remaining life prediction result is output by jointly solving the oxide layer growth rate equation and the Paris fatigue model, and its expression is: , where is the remaining life of the oxide layer, is the current oxide layer thickness, is the critical failure thickness, is the effective stress, is the pre-exponential factor, representing the frequency factor of the oxidation reaction, is the ideal gas constant, is the stress exponent, is the oxygen partial pressure contribution coefficient, is the oxygen partial pressure, is the oxygen partial pressure exponent, is the oxide layer growth rate expression.

[0016] The present invention provides an optical coherence tomography detection method for thermally grown oxides of an aeroengine. The method collects the interference signal of the reference light field and the sample scattered light field, performs adaptive polarization state compensation on the interference signal based on the dynamic polarization matching factor, and obtains the compensated interference signal; performs anisotropic filtering on the compensated interference signal, retains the signal discontinuity at the columnar crystal grain boundaries by the grain boundary discontinuity index constraint, separates the columnar crystal structure characteristics of the oxide layer, and obtains the filtered signal; performs time-frequency joint analysis on the filtered signal, optimizes the time-frequency transformation kernel parameters by the adaptive window width adjustment factor, and extracts the oxide layer thickness and the frequency band energy distribution; fuses the columnar crystal structure characteristics and the frequency band energy distribution, constructs a cross-scale thermodynamic inversion model, and outputs the prediction result of the remaining life of the oxide layer of the engine's thermally grown oxides. The beneficial effects generated include: Improve imaging quality and structure recognition ability: By introducing the dynamic polarization matching factor and constructing a sparse regularization optimization model, realize the adaptive polarization state compensation of the interference signal, significantly improve the OCT imaging clarity and interference signal-to-noise ratio in a complex multi-scattering environment, and enhance the resolvability of the columnar crystal structure in the thermally grown oxide layer; Enhance the physical correlation between frequency domain analysis and thickness extraction: Propose an adaptive window width adjustment mechanism and a genetic optimization strategy, realize the dynamic optimization of the time-frequency transformation kernel function, and convert the frequency band energy into physical thickness through non-linear mapping and oxidation kinetics modeling, improving the accuracy of thickness detection and the physical interpretation ability; Realize cross-scale thermodynamics behavior modeling and life prediction: Integrate crystal structure and frequency-domain energy information, construct a multi-field coupling inversion model considering the influence of grain boundary discontinuity and stress nonlinearity, and quantify the uncertainty of modeling parameters based on the Bayesian Markov chain Monte Carlo method to achieve high-precision prediction of the remaining life of the oxide layer.

[0017] The above description is only an overview of the technical solution of this application. In order to be able to understand the technical means of this application more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features and advantages of this application more obvious and understandable, the specific embodiments of this application are specifically given below. Brief Description of the Drawings

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings. In the drawings: Figure 1 It is a flowchart of an optical coherence tomography detection method for thermally grown oxides of an aeroengine shown in an exemplary embodiment of the present invention. Detailed Description of the Embodiments

[0019] The following will describe the embodiments of the present invention with reference to the drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for explaining the present invention, rather than for limiting the protection scope of the present invention.

[0020] It should be noted that the diagrams provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner. Therefore, only the components related to the present invention are shown in the diagrams, rather than being drawn according to the number, shape and size of the components in actual implementation. The type, number and proportion of each component in actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0021] In the following description, a large number of details are explored to provide a more thorough explanation of the embodiments of the present invention. However, it is obvious to those skilled in the art that the embodiments of the present invention can be implemented without these specific details. In other embodiments, well-known structures and devices are shown in the form of block diagrams rather than in detail to avoid making the embodiments of the present invention difficult to understand. Embodiment 1

[0022] Optical Coherence Tomography Detection Method for Thermally Grown Oxides of Aero-engines, as Figure 1 shown, including: S1: Collect the interference signal of the reference light field and the sample scattered light field, perform adaptive polarization state compensation on the interference signal based on the dynamic polarization matching factor, and obtain the compensated interference signal; S2: Perform anisotropic filtering on the compensated interference signal, retain the signal discontinuity at the columnar crystal grain boundaries by constraining with the grain boundary discontinuity index, separate the columnar crystal structure characteristics of the oxide layer, and obtain the filtered signal; S3: Perform time-frequency joint analysis on the filtered signal, optimize the time-frequency transformation kernel parameters using the adaptive window width adjustment factor, and extract the oxide layer thickness and frequency band energy distribution; S4: Integrate the columnar crystal structure characteristics and the frequency band energy distribution, construct a cross-scale thermodynamic inversion model, and output the prediction result of the remaining life of the oxide layer of the engine's thermally grown oxides.

[0023] The present invention is further configured such that the interference signal of the reference light field and the sample scattered light field is collected, the interference signal is analyzed, the phase information of the analyzed signal is extracted, the dynamic polarization matching factor is calculated, a sparse regularization optimization problem is constructed, the polarization compensation matrix is dynamically adjusted, and the polarization state of the interference signal is corrected using the updated polarization compensation matrix to obtain the compensated interference signal. Specifically, the steps for obtaining the compensated interference signal include: Model the interference signal: , where is the interference signal, is the complex amplitude of the reference light field, is the complex amplitude of the sample scattered light field, , is the independent intensity of the reference light and the sample light, take the real part of the complex number, is the complex conjugate of the reference light field, is the spatial position, is the time variable; Perform the Hilbert transform on along the time axis to extract the orthogonal component: , where is the analytic signal, is the imaginary part after the Hilbert transform, generating a component orthogonal to the original signal, is the signal envelope, representing the intensity distribution of the interference signal, and its formula is: , , is the phase field, containing sample depth and dynamic change information, and its formula is: , is the imaginary unit; Calculate the dynamic polarization matching factor , construct a sparse regularization optimization problem, and dynamically adjust the polarization compensation matrix: , where is the regularization weight, is the Jones matrix, is the phase distortion field, is the ideal optical field, is the compensated phase field, is the square of the gradient of the compensated phase field; Iteratively solve the sparse regularization optimization problem. When , use the alternating direction multiplier method to update : , where is the updated Jones matrix. When iterating to or reaching the maximum number of iterations , the iteration terminates; Use the updated to correct the polarization state of the interference signal: , where is the compensated interference signal; Through dynamic polarization matching and sparse optimization, the core problem of interference signal distortion in the high-temperature and high-turbulence environment of aeroengines is solved. Incorporate the fluid mechanics model into the real-time compensation logic, combine the sparse constraint of the Jones matrix, and achieve a balance among anti-interference performance, accuracy, and efficiency, providing a highly reliable solution for oxide layer detection.

[0024] The present invention is further configured such that the dynamic polarization matching factor is dynamically updated through the sparse constraint of the phase gradient tensor product and the polarization compensation matrix, and its expression is: , where is the dynamic polarization matching factor, is the spatial phase gradient, is the phase distortion field, is the Frobenius norm, is the Jones matrix of the trace, is the Jones matrix of the conjugate transpose matrix, is the adjustment parameter. Specifically, the spatial phase gradient is calculated from the phase field , and its formula is: , where , are the orthogonal coordinate axes in the two-dimensional space, corresponding to the transverse scanning direction of the detection, is the transpose operator, and the phase distortion field is caused by turbulent perturbations and mixed with noise terms in Construct the phase distortion field as the tensor product with the spatial phase gradient Quantify the phase distortion field and the coupling strength with the spatial phase gradient reflects the degree of polarization mismatch constrain the sparsity of the compensation matrix to avoid overfitting By coupling the phase gradient and the distortion field through the tensor product, combining the sparse energy constraint of the Jones matrix, a high-precision calculation framework for the dynamic polarization matching factor is constructed. Integrating the hydrodynamic perturbation and the structural characteristics, a double breakthrough in anti-interference ability and detection accuracy is achieved, providing key technical support for the oxide layer health management of the hot-end components of aeroengines

[0025] The present invention is further configured such that the depth-resolved diffusion model is constructed based on the anisotropic dielectric tensor of the oxide layer columnar crystal structure. The mutation intensity of the dielectric constant is quantified by the grain boundary discontinuity index, and the signal discontinuity retention in the filtering process is weighted and constrained. An iterative algorithm is used to solve the joint optimization problem of the anisotropic diffusion equation and the grain boundary constraint, separate the oxide layer columnar crystal structure characteristics, and obtain the filtered signal. Specifically, based on the anisotropic characteristics of the oxide layer columnar crystal, the main axis components of the dielectric tensor are defined as , , where , , is the dielectric constant in different directions is the base dielectric constant , is the material constant is the porosity distribution is the depth Utilize the interference signal envelope attenuation characteristic to invert the porosity distribution , where is the initial amplitude is the envelope signal is the absorption coefficient represents the exponential attenuation caused by the absorption effect when the signal propagates in the medium Calculate the grain boundary discontinuity index, construct and solve the joint optimization model of the anisotropic diffusion equation and the grain boundary constraint, and obtain the filtered signal. The model expression is , where is the original depth signal , is the auxiliary variable , , is the weight parameter, , is the depth at the depth signal, is the grain boundary discontinuity index, is the target signal to be optimized, representing the filtered interference signal, is spatial phase gradient field of; Through anisotropic dielectric tensor modeling and grain boundary constraint weighting, high-precision separation of the columnar crystal structure of the oxide layer is achieved. Incorporating material physical properties into the filtering algorithm and combining with Split-Bregman for efficient solution significantly improves the balance ability of noise suppression and edge preservation, providing a reliable microstructural data basis for the failure analysis of hot-end components of aeroengines.

[0026] The present invention is further configured such that the grain boundary discontinuity index is calculated by the normalized ratio of the dielectric constant mutation to the grain size, and its expression is: , where is the grain boundary discontinuity index, and are the dielectric constants on both sides of the grain boundary, is the depth position, is the average grain diameter, is the system axial resolution, represents the second moment of the dielectric constant component , defined as: , where is the total number of sampling points in the depth direction of the oxide layer, is the depth position; specifically, the formula realizes high-robust quantification of grain boundary discontinuity through dielectric mutation intensity, global normalization, and size resolution correction, providing a key criterion for the precise separation of the columnar crystal structure of the aeroengine oxide layer. Integrating material physical properties and detection system parameters significantly improves the microfeature retention ability and algorithm adaptability, supporting the construction of a high-reliability life prediction model.

[0027] The present invention is further configured such that the time-frequency joint analysis of the filtered signal includes: Optimizing the time-frequency transformation kernel parameters using an adaptive window width adjustment factor; Generating an optimal time-frequency distribution by maximizing the weighted fitness function of the frequency band energy and signal-to-noise ratio through a genetic algorithm; Nonlinearly compress the band energy based on the hyperbolic tangent function, combine the weighted summation of the coefficients calibrated by the Arrhenius equation of oxidation kinetics, and map it to the physical thickness interval through the Sigmoid function to extract the oxide layer thickness and band energy distribution. Specifically, the steps of optimizing the time-frequency transformation kernel by the genetic algorithm include: Through chromosome coding, the window parameter is encoded into a binary gene string, and the search range is defined , , is the cut-off frequency; Design the fitness function. When the convergence condition is reached, output the optimal window parameter ; Utilize the hyperbolic tangent function to compress the nonlinear effect of band energy: , is the compressed band energy, control the compression rate, calibrated by the Arrhenius equation; According to the compressed band energy, perform weighted summation and saturation mapping to calculate the oxide layer thickness, and its formula is: , where is the oxide layer thickness, is the oxidation kinetic parameter, is the Sigmoid function, is the reference thickness, is to control the saturation rate, is the total number of bands; Through adaptive time-frequency analysis, oxidation kinetics calibration and nonlinear mapping, achieve high-precision extraction of the thickness and energy distribution of thermally grown oxides in aeroengines. Deeply integrate the materials science model and signal processing technology to solve the problems of weak signal detection and physical parameter inversion in high-temperature and high-noise environments, and provide a reliable data basis for engine health management.

[0028] The present invention is further set that the adaptive window width adjustment factor is calculated by the elastic coefficient of the window scale parameter with respect to the band energy and the frequency shift cut-off matching degree, and its expression is: , where is the adaptive window width adjustment factor, is the total number of bands, is the band energy of the window scale parameter, Calculate the elastic coefficient of the band energy, and take the derivative of with respect to to represent the sensitivity of the window scale parameter to the band energy , Calculate the frequency shift cut-off matching degree, is the frequency band translation parameter, is the cut-off frequency, , through the joint optimization of the elastic coefficient and the frequency shift matching degree, realizes the adaptive adjustment of the time-frequency analysis window width, and solves the resolution imbalance problem of the traditional fixed window width in the detection of the oxidation layer of aeroengines. Incorporating the local characteristics of the signal into the window parameter decision significantly improves the physical interpretability and engineering practicability of the time-frequency distribution, and provides a high-precision tool for the analysis of the dynamic evolution of the oxidation layer.

[0029] The present invention is further configured such that the construction of the cross-scale thermodynamic inversion model includes: Fusing the columnar crystal structure characteristics and the frequency band energy distribution to establish a multi-field coupling constitutive equation, where the oxidation activation energy is corrected by the grain boundary discontinuity index, and the stress index is non-linearly modulated by the frequency band energy; Solving the parameters of the oxidation layer growth rate equation based on the Bayesian Markov chain Monte Carlo inversion method, and quantifying the uncertainty of the remaining life prediction by combining Monte Carlo simulation; The inversion parameters are dynamically fed back to the preprocessing step to form a detection-modeling-prediction closed-loop optimization. Specifically, by fusing the microstructure characteristics and the macroscopic energy distribution, a multi-field coupling oxidation kinetics equation is constructed, and the Bayesian MCMC and Monte Carlo methods are used to achieve high-precision inversion of the parameters and uncertainty quantification. The grain boundary discontinuity index and the frequency band energy respectively correct the activation energy and the stress index, breaking through the limitations of the traditional single-scale model. The inversion parameters are dynamically fed back to the preprocessing step to form a global optimization of detection-modeling-prediction.

[0030] The present invention is further configured such that the cross-scale thermodynamic inversion model corrects the oxidation activation energy through the grain boundary discontinuity index, and its expression is: , where is the maximum grain boundary discontinuity index, is the dynamic polarization matching factor, is the corrected value of the oxidation activation energy, is the reference oxidation activation energy, is the Boltzmann constant, is the absolute temperature, is the adjustment coefficient. Specifically, through the joint correction of the grain boundary discontinuity index and the dynamic polarization factor, a cross-scale thermodynamic model of the oxidation activation energy is constructed to solve the prediction deviation problem of the traditional single-scale model in a high-temperature, multi-field coupling environment. This model significantly improves the accuracy and reliability of the oxidation layer life prediction of the hot-end components of aeroengines.

[0031] The present invention is further configured such that the remaining life prediction result is output by jointly solving the oxidation layer growth rate equation and the Paris fatigue model, and its expression is: , where is the remaining life of the oxide layer, is the current thickness of the oxide layer, is the critical failure thickness, is the effective stress, is the pre-exponential factor, representing the frequency factor of the oxidation reaction, is the ideal gas constant, is the stress exponent, is the oxygen partial pressure contribution coefficient, is the oxygen partial pressure, is the oxygen partial pressure exponent, is the expression of the oxide layer growth rate. Specifically, the expression is obtained by jointly solving the oxide layer growth rate equation and the Paris fatigue model to construct a high-precision prediction model for the remaining life of the thermally grown oxide in an aero-engine, integrating the synergistic effects of temperature, stress, and oxygen partial pressure on the oxidation rate, breaking through the limitations of traditional single-field models, significantly reducing the uncertainty of oxide layer life prediction, and providing a key technical guarantee for reducing maintenance costs and avoiding unexpected failures.

[0032] For the optical coherence tomography detection method of the thermally grown oxide in the aero-engine provided in the above embodiment, the specific manners in which each module and unit perform operations have been described in detail in the method embodiment and will not be elaborated here. In practical applications, for the low-altitude ground-based information fusion system provided in the above embodiment, the above functions can be allocated to different functional modules as needed, that is, the internal structure of the system is divided into different functional modules to complete all or part of the functions described above, and no limitation is imposed here either.

[0033] The above embodiments can be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented using software, the above embodiments can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer programs are loaded or executed on a computer, the processes or functions described in the embodiments of the present application are generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center by wired (such as infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or a data center that contains one or more collections of available media. The available media can be magnetic media (such as floppy disks, hard disks, magnetic tapes), optical media (such as DVDs), or semiconductor media. The semiconductor media can be a solid-state drive.

[0034] It should be understood that the term "and / or" in this document is merely a description of the association relationship between associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. Here, A and B can be singular or plural. In addition, the character " / " in this document generally represents an "or" relationship between the associated objects before and after, but it may also represent an "and / or" relationship, which can be specifically understood with reference to the context.

[0035] In this application, "at least one" means one or more, and "a plurality" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single items or plural items. For example, at least one of a, b, or c can represent: a, b, c, a - b, a - c, b - c, or a - b - c, where a, b, and c can be single or multiple.

[0036] It should be understood that in various embodiments of the present application, the magnitudes of the sequence numbers of the above processes do not mean the order of execution. The order of execution of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.

[0037] Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of this application.

[0038] Those skilled in the art can clearly understand that for the convenience and conciseness of description, the specific working processes of the systems, devices, and units described above can refer to the corresponding processes in the foregoing method embodiments, and will not be elaborated herein.

[0039] In several embodiments provided in this application, it should be understood that the disclosed systems can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed couplings or direct couplings or communication connections to each other can be through some interfaces. The indirect couplings or communication connections of devices or units can be electrical, mechanical, or other forms.

[0040] The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they can be located in one place, or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0041] In addition, the functional units in each embodiment of this application can be integrated in a processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit.

[0042] When the above-mentioned function is implemented in the form of 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 application, in essence, or the part that contributes to the prior art or a part of this 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 for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of this application. The foregoing storage medium includes: various media that can store program codes, such as USB flash drives, mobile hard disks, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical discs.

[0043] As described above, the above are only specific implementation manners of this application, but the protection scope of this application is not limited thereto. Any person skilled in the art within the technical scope disclosed by this application can easily think of changes or substitutions, which should all be covered within the protection scope of this application. Therefore, the protection scope of this application shall be subject to the protection scope of the claims.

Claims

1. An optical coherence tomography detection method for thermally grown oxides in an aeroengine, characterized in that Including: S1: Collect the interference signal of the reference light field and the sample scattered light field, perform adaptive polarization state compensation on the interference signal based on the dynamic polarization matching factor, and obtain the compensated interference signal. S2: Perform anisotropic filtering on the compensated interference signal, retain the signal discontinuity at the columnar crystal grain boundary through the grain boundary discontinuity index constraint, separate the columnar crystal structure characteristics of the oxide layer, and obtain the filtered signal. S3: Perform time-frequency joint analysis on the filtered signal, optimize the time-frequency transformation kernel parameters using the adaptive window width adjustment factor, and extract the oxide layer thickness and frequency band energy distribution. S4: Integrate the columnar crystal structure characteristics and the frequency band energy distribution, construct a cross-scale thermodynamic inversion model, and output the prediction result of the remaining life of the engine thermally grown oxide layer.

2. The optical coherence tomography detection method for thermally grown oxides of an aeroengine according to claim 1, wherein Collect the interference signal of the reference light field and the sample scattered light field, analyze the interference signal, extract the phase information of the analyzed signal, calculate the dynamic polarization matching factor, construct a sparse regularization optimization problem, dynamically adjust the polarization compensation matrix, and use the updated polarization compensation matrix to correct the polarization state of the interference signal to obtain the compensated interference signal.

3. The optical coherence tomography detection method for thermally grown oxides of an aeroengine according to claim 2, characterized in that, The dynamic polarization matching factor is dynamically updated through the sparsity constraint of the phase gradient tensor product and the polarization compensation matrix, and its expression is: , where is the dynamic polarization matching factor, is the spatial phase gradient, is the phase distortion field, is the Frobenius norm, is the Jones matrix is the trace of is the Jones matrix is the conjugate transpose matrix of is the adjustment parameter.

4. The optical coherence tomography detection method for thermally grown oxides of an aeroengine according to claim 2, wherein Construct a depth-resolved diffusion model based on the anisotropic dielectric tensor of the columnar crystal structure of the oxide layer, quantify the mutation intensity of the dielectric constant through the grain boundary discontinuity index and weighted constraint to retain the signal discontinuity during the filtering process, and use an iterative algorithm to solve the joint optimization problem of the anisotropic diffusion equation and the grain boundary constraint to separate the columnar crystal structure characteristics of the oxide layer and obtain the filtered signal.

5. The optical coherence tomography detection method for thermally grown oxides of an aeroengine according to claim 4, characterized in that, The grain boundary discontinuity index is calculated by the normalized ratio of the dielectric constant mutation to the grain size, and its expression is: , where is the grain boundary discontinuity index, and are the dielectric constants on both sides of the grain boundary, is the depth position, is the average grain diameter, is the system axial resolution, represents the second moment of the dielectric constant component , which is defined as: , where is the total number of sampling points in the depth direction of the oxide layer, is the depth position.

6. The optical coherence tomography detection method for thermally grown oxides of an aeroengine according to claim 4, characterized in that, Perform time-frequency joint analysis on the filtered signal, including: Optimize the time-frequency transformation kernel parameters using the adaptive window width adjustment factor; Maximize the weighted fitness function of the frequency band energy and the signal-to-noise ratio through the genetic algorithm to generate the optimal time-frequency distribution; Nonlinearly compress the frequency band energy based on the hyperbolic tangent function, combine the coefficients calibrated by the Arrhenius equation of oxidation kinetics for weighted summation, and map to the physical thickness interval through the Sigmoid function to extract the oxide layer thickness and the frequency band energy distribution.

7. The optical coherence tomography detection method for thermally grown oxides of an aeroengine according to claim 6, wherein The adaptive window width adjustment factor is calculated by the elastic coefficient of the window scale parameter with respect to the band energy and the frequency shift cut-off matching degree. Its expression is as follows: , where is the adaptive window width adjustment factor, is the total number of bands, is the band energy of the window scale parameter, calculates the elastic coefficient of the band energy, calculates the frequency shift cut-off matching degree, is the frequency shift parameter of the cut-off frequency, .

8. The optical coherence tomography detection method for thermally grown oxides of an aeroengine according to claim 1, wherein The construction of the cross-scale thermodynamic inversion model includes: Integrate the columnar crystal structure characteristics and the frequency band energy distribution, establish a multi-field coupling constitutive equation, in which the oxidation activation energy is corrected by the grain boundary discontinuity index and the stress index is nonlinearly modulated by the frequency band energy; Solve the parameters of the oxide layer growth rate equation based on the Bayesian Markov chain Monte Carlo inversion method, and quantify the uncertainty of the remaining life prediction by combining Monte Carlo simulation; Dynamically feedback the inversion parameters to the preprocessing step to form a closed-loop optimization of detection-modeling-prediction.

9. The optical coherence tomography detection method for thermally grown oxides of an aeroengine according to claim 3 or 5, characterized in that The cross-scale thermodynamic inversion model corrects the oxidation activation energy through the grain boundary discontinuity index, and its expression is: , where is the maximum grain boundary discontinuity index, is the dynamic polarization matching factor, is the corrected value of the oxidation activation energy, is the reference oxidation activation energy, is the Boltzmann constant, is the absolute temperature, is the adjustment coefficient.

10. The optical coherence tomography detection method for thermally grown oxides of an aeroengine according to claim 9, characterized in that, The remaining life prediction result is output by jointly solving the oxide layer growth rate equation and the Paris fatigue model, and its expression is: , where is the remaining life of the oxide layer, is the current oxide layer thickness, is the critical failure thickness, is the effective stress, is the pre-exponential factor, representing the frequency factor of the oxidation reaction, is the ideal gas constant, is the stress exponent, is the oxygen partial pressure contribution coefficient, is the oxygen partial pressure, is the oxygen partial pressure exponent, is the oxide layer growth rate expression.

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