18 results about "Wave mode" patented technology

The present application relates to the technical field of pipeline nondestructive testing, and discloses a pipeline defect diagnosis method based on guided wave technology. The method obtains original guided wave response signals under multiple excitation frequencies through a guided wave sensor array arranged on the outer wall of the pipeline, performs multi-stage analysis and separation on the signals, extracts a set of independent wave mode components directly related to the defects, including longitudinal wave components, torsional wave components and surface wave components. According to the propagation time delay and energy distribution of each component, a multi-dimensional defect feature tensor is constructed, input into a trained pipeline defect discrimination network for feature mapping and abstraction, and a preliminary diagnosis report of the defect category and geometric profile is output. Combined with the pipeline service environment parameters, the physical field coupling correction is carried out to generate the final diagnosis result. The method solves the problems of serious mode aliasing and poor environmental adaptability in the traditional guided wave technology, and realizes accurate identification and positioning of defects.

The present application relates to the test method and system of the effect stress field simulation wave shape mode of cold-rolled thin strip, the method comprises the following steps: obtaining the cold-rolled thin strip sample, treating the cold-rolled thin strip sample to form the original speckle, detecting and calibrating the original speckle, and obtaining the test result by heating the local heating area to simulate the wave shape evolution process.The present application simulates the residual stress and wave shape evolution process of the cold-rolled thin strip by using thermal stress and records, which is convenient for the research of elastic buckling theory and strip shape control technology.

A surface acoustic wave device (5) is provided using a layered substrate system with a special material and a special cut of a piezoelectric thin film (4) selected for utilizing Rayleigh mode. The proper choice of the material and the cut of the piezoelectric thin film leads to a low velocity of the excited wave mode, which allows the usage of smaller devices without deteriorating other performance parameters according to specifications.

The invention belongs to the technical field of guided wave mode identification, and particularly relates to a time domain wave field guided wave mode identification method based on phase compensation, a program, equipment and a storage medium. According to the method, the guided wave mode existing in the wave field is obtained in the time domain wave field by using the two guided wave signals collected in a close range and adopting a phase compensation method, and the guided wave mode identification can be realized only by using a small number of signals through the method for performing phase compensation on the guided wave signals, so that the practicability of the guided wave mode identification method is greatly improved; and a foundation is laid for the subsequent application of the guided wave technology. According to the method, the similarity evaluation index between the guided wave signals in the window is introduced, so that automatic multi-mode identification of the guided wave mode of the time domain wave field is realized, the efficiency of guided wave mode identification is greatly improved, and the precision of guided wave mode identification is improved.

The present invention relates to a volume acoustic component (100) with an annular piezoelectric layer (10) having radius R, thickness d and width b and an electrode arrangement with at least one cathode (12) and at least one anode (11). The annular piezoelectric layer (10) has at least one Lamb-wave mode with propagation direction along the azimuthal direction of the annular piezoelectric layer (10).

The invention provides a cross-domain generation method from a sea wave spectrum to an SAR (Synthetic Aperture Radar) image for sea wave observation, which relates to the technical field of sea wave observation and comprises the following steps: acquiring GF-3SAR wave mode data, and preprocessing the wave mode data; eRA-5 sea wave spectrum data matched with the GF-3SAR wave mode data in a space-time mode are obtained, the sea wave spectrum data are preprocessed, and a new spatial domain imaginary part feature map is obtained; forming a matching data set by the obtained data, grouping the matching data set along the azimuth direction, the distance direction and other directions of the SAR according to sea wave propagation, and dividing the matching data set into two parts, namely a training set and a test set; inputting the training set data into the improved generative adversarial network, and obtaining a network weight through network training; and taking the ERA-5 data in the test set as input, generating SAR data through the network weight obtained by training, performing multi-index comparison on the real SAR data and the generated SAR data, and confirming a generation effect.

The application provides an iterative quantitative imaging method based on a nonlinear Lamb wave mixing sound field, and steps are as follows: a finite element model of a metal plate containing a complex mode early damage is established; a mixing fundamental wave mode pair and a working frequency are determined; mixing sound field signals in a non-damage state and a damage state are obtained through finite element simulation, and a frequency domain sound field matrix of a difference frequency, a sum frequency and a fundamental frequency is extracted; ray tomography positioning representation is carried out by using the frequency domain sound field matrix of the difference frequency, first imaging is realized, the first imaging is fused with the fundamental frequency sound field feature to strengthen positioning representation, and an initial velocity model of iterative quantitative imaging is established; an offline training data set is constructed, a nonlinear mapping model of sound field changes and model changes is learned based on a conjugate gradient method, online inversion based on the optimal nonlinear mapping model is carried out, and second imaging is realized; and the application extracts the sum frequency and the difference frequency component, keeps high sensitivity of the nonlinear ultrasonic to microscopic and mesoscopic damage, and significantly improves detection reliability.

The invention discloses a rod bundle channel flow instability early warning method based on disturbance wave modal identification, and relates to the technical field of nuclear reactor thermal hydraulic safety. The method comprises the steps of collecting a multi-source signal of a two-phase flow in a target rod bundle channel, and performing preprocessing to obtain multi-channel time sequence data; reconstructing space-time evolution information of the disturbance wave field and the two-phase flow characteristic parameters based on the multi-channel time sequence data; modal decomposition is carried out on the spatio-temporal evolution information, and modal characteristic parameters after decomposition are calculated; based on a preset early warning criterion, the modal characteristic parameters obtained through real-time calculation are evaluated; the early warning criterion is associated with a mapping relation between different flow instability types and specific disturbance wave modal characteristic parameters; and according to an evaluation result, executing graded early warning and outputting related information. According to the method, the flow instability early warning and type distinguishing in the accident can be realized by identifying and analyzing the modal characteristics of the specific disturbance waves in the flow channel in real time.

This invention discloses a cement velocity inversion method based on arrayed ultrasonic Lamb waves, belonging to the field of oil and gas well exploration and development technology. It solves the technical problems of low computational efficiency and limited applicable velocity range in cement velocity inversion algorithms. The method includes: performing spatiotemporal preprocessing on the array signal to obtain the target guided wave mode, and extracting the complex dispersion curve of the target guided wave mode; constructing a three-layer planar medium model and deriving the dispersion matrix; setting the acoustic parameters of the well fluid and casing, generating multiple sets of initial value sequences for the parameters to be inverted, and calculating the determinant of the dispersion matrix; constructing a loss function, iteratively updating the parameters to be inverted and repeating the process until the number of iterations reaches a preset iteration threshold; traversing all sets of initial value sequences and extracting the iteration parameters corresponding to the round in which the loss function reaches its minimum value. This invention broadens the applicable working conditions and universality, facilitates automated and batch processing, and improves computational efficiency.

The application relates to a laser-ultrasonic excitation light source parameter optimization method based on finite element simulation, which comprises the following steps: constructing a finite element simulation model of a target material; based on a laser ablation physical mechanism, converting a phase change and a gasification process induced by incident laser on the surface of the target material into equivalent stress acting on the surface of the finite element simulation model; in the finite element simulation model, a plurality of groups of excitation light source parameters are adjusted coordinately, ultrasonic signal responses excited by the equivalent stress under different excitation light source parameter combinations are solved and obtained; time-frequency characteristics of a target wave mode in the ultrasonic signal responses are extracted, and an optimal excitation light source parameter combination is determined from the plurality of groups of excitation light source parameters by taking improvement of signal signal-to-noise ratio and high-frequency components as an optimization target. Through the equivalent stress conversion mechanism of latent heat of vaporization and the finite element model, the excitation source multi-parameters are determined, so that the detection accuracy and adaptability are improved.

This invention discloses a method, system, device, and medium for forward calculation and performance prediction of acoustic superstructures, relating to the field of vibration reduction and noise reduction technology. The method includes: constructing a finite element model of periodic elements to obtain the stiffness and mass matrices; introducing periodic boundary conditions to transform the wave control equations into a nonlinear eigenvalue problem of complex wavenumbers; employing a contour integral algorithm to solve all characteristic wavenumbers and corresponding generalized eigenvectors in one step within a pre-set closed contour in the complex wavenumber plane; automatically matching and tracking characteristic wavenumbers of the same physical wave branch based on eigenvector similarity in the target frequency domain, and plotting a continuous dispersion curve; identifying vibration bandgap based on the dispersion curve, recovering the generalized eigenvectors to physical space for wave mode analysis, and completing performance prediction. This invention overcomes the computational efficiency bottleneck of traditional methods in complex element and mid-to-high frequency analysis, reveals the wave coupling mechanism of bandgap generation, and provides core support for topology optimization of acoustic superstructures.

This application discloses a stabilization and control method based on a wind-wave combined unit, belonging to the field of marine energy utilization. Addressing the problems in improving the stability and wind and wave resistance of large floating offshore wind turbines in existing technologies, this application utilizes a dynamic mode decomposition algorithm to reduce the dimension and decouple the wave field. The dominant wave modes are extracted within the optimal range of the floating body's relative motion and used to construct a reduced-order model. Finally, wave dynamics are predicted based on the development trends of each mode in the reduced-order model. According to the platform's motion response, the floating body is locked or released under appropriate wave surface conditions to timely gain energy or adjust the unit's attitude.

This invention discloses a method and system for joint detection of temperature and stress using ultrasonic guided waves, belonging to the field of structural health monitoring technology. To address the severe interference from temperature effects in traditional guided wave stress measurements, this invention proposes a joint inversion scheme that requires no external temperature compensation. It includes a guided wave transceiver unit, a signal processing unit, and a temperature-stress joint inversion engine. The core principle is to optimize the operating frequency to maximize the difference in sensitivity to temperature and stress between at least two guided wave modes excited at this frequency; and to simultaneously calculate temperature and stress values ​​using an inversion model trained based on multi-mode propagation parameters at this frequency. This invention also includes a domain randomization strategy for constructing a high-fidelity training database and an online baseline calibration method, effectively improving the model's generalization ability and practical accuracy. The system of this invention has a simple structure, strong anti-interference capability, and can achieve high-precision, in-situ synchronous monitoring of structural stress and temperature under extreme environments.

Disclosed are methods of preparing a Surface Acoustic Wave (SAW) device, comprising: sequentially depositing a Cu electrode, a silicon oxide film, modifying the surface of the silicon oxide film, and then depositing a piezoelectric film, and an Al electrode on a substrate having an interdigital (IDT) electrode pattern to obtain the SAW device. In some embodiments, the Cu and Al electrodes both have IDT electrode patterns corresponding to the IDT pattern of the substrate. Because the Sezawa wave mode that is adopted is formed by coupling film thickness vibration and transverse vibration, the present invention is characterized in that a longitudinal electric field and a transverse electric field are excited through the double-layer electrodes whereby the electromechanical coupling coefficient of the SAW device can be improved by changing the coupling pattern between the electric fields and the piezoelectric film.

This invention discloses a method for locating and imaging local micro-defects based on nonlinear ultrasonic guided wave mixing, belonging to the field of nondestructive testing technology. The method includes: screening guided wave modes on the material under test; exciting two fundamental frequency guided wave signals to form a mixing region in the material; measuring the propagation velocity of the fundamental frequency guided waves and calculating the mixing point position; adjusting the excitation delay to achieve mixing point movement and region scanning; acquiring signals and performing frequency domain analysis to extract the nonlinear mixing signal; and then performing defect determination and imaging. This invention utilizes the high sensitivity of nonlinear ultrasonic guided wave mixing to micro-damage, achieving precise location and imaging of early-stage micro-defects in materials, thus solving the problem of insufficient identification capability of traditional nondestructive testing methods for minute damage.

The invention relates to a mechanical vibration simulation / test analysis technology, and discloses a method and system for extracting a gear traveling wave modal, and the method comprises the steps: obtaining a gear time domain vibration response signal of any point on a gear through simulation or measurement; performing Fourier transform on the gear time domain vibration response signal to obtain a gear frequency domain response signal; extracting a side frequency amplitude and a phase under the resonance rotating speed; enabling the amplitude and the phase of each side frequency to correspond to the amplitude and the phase of the pitch diameter component of the gear; and determining the traveling wave resonance modal response through the amplitude and phase of the pitch diameter component of the gear and the inherent frequency. According to the invention, only one sensor rotating along with the gear is needed in an experimental test, so that a vibration signal on the whole circumference of the gear can be obtained; in dynamics simulation, vibration signals on the whole circumference of the gear can be obtained only by storing vibration data of one point on the gear, and the storage space is greatly reduced.

The present invention pertains to the technical field of pipe inspection, wherein instrumented pipe inspection tools (“pipeline inspection tools”—pigs) are used to verify the structural integrity of said pipes and describes a pipe inspection tool comprising a tool body and at least two articulated arms, wherein each articulated arm connects the tool body to a sensor and keeps said sensor in direct contact with the inner surface of a pipe.