28 results about "Wave mode" patented technology

The invention provides an ocean vortex region one-dimensional wave spectrum inversion method based on a synthetic aperture radar, and the method comprises the steps: recognizing an ocean vortex through HY-2 fusion data, collecting a Sentinel-1 dual-polarized SAR image covering a vortex region, and obtaining WAVEWATCH-III wave mode data; a hydrodynamic modulation transfer function is improved, and a vortex shear flow influence factor is introduced; an XGBoost machine learning model is adopted, and an ocean vortex region SAR one-dimensional sea wave spectrum inversion algorithm is established; and verifying the accuracy of the SAR one-dimensional sea wave spectrum inversion algorithm. According to the method, the precision limitation of traditional wave theory inversion in a vortex region is broken through, and the one-dimensional wave spectrum inversion precision is improved.

The invention relates to a nondestructive flaw detection method and system, and the method comprises the steps: carrying out the dynamic coupling wave mode decomposition of a response signal, and obtaining a basic wave mode component and an energy ratio; aiming at a plurality of discrete time-frequency scale units, constructing a multi-scale time-frequency energy flow graph cluster based on the basic wave mode component and the energy ratio; calculating the direction gradient of each energy flow graph in the energy flow graph cluster by taking the energy amplitude as the weight to obtain a gradient vector field; determining a suspicious region according to topological structure characteristics of the gradient vector field and an abnormal threshold value of a wave mode energy ratio in the energy flow graph cluster; determining the boundary of the suspicious region based on the trajectory of the gradient vector field; performing depth distribution inversion calculation on the suspicious region according to the energy attenuation gradient of the multi-scale energy flow diagram and the attenuation of each basic wave mode energy in the depth direction; and performing regularization tomography by using the energy ratio and spatial distribution of each fundamental wave mode as multi-channel input, and reconstructing the three-dimensional geometrical morphology of the suspicious region.

The application discloses an asymmetric phase-shifting control method suitable for a half-wave shaping MMC, and can realize wide-range operation energy balance of a converter. The method is characterized in that, in a 2pi period, a commutation unit switching function and a multi-level unit modulation voltage are not switched in a half-wave period pi, but in a positive half-wave mode, [0, pi] is taken as a reference to expand and shift an angle theta to the left and right, that is, the interval is [-theta, pi+theta], and in a negative half-wave mode, [pi, 2pi] is taken as a reference to shrink and shift an angle theta to the left and right, that is, the interval is [pi+theta, 2pi-theta]. The application adopts an asymmetric phase-shifting modulation method, generates and reverses polarities of two asymmetric partial sine waves through a commutation switch cooperating with a multi-level unit, and obtains a complete multi-level sine wave on an alternating current side. The application can eliminate the limitation of a power factor angle on a phase-shifting angle while realizing wide-range energy balance of the converter, is only affected by a modulation ratio, and compared with symmetric phase-shifting modulation, is beneficial to simplifying commutation control logic when the system is in a wide-range reactive power regulation, and has better engineering application value.

The embodiment of the invention provides a complex special-shaped structure three-dimensional stress inversion method based on ultrasonic characteristic guided waves, and the method comprises the steps: obtaining first ultrasonic characteristic guided waves corresponding to a plurality of characteristic guided wave modes of a detected special-shaped structure in a detection process, the multiple characteristic guided wave modes comprise at least two of a longitudinal mode, a torsional mode and a bending mode; according to the first ultrasonic characteristic guided waves corresponding to the multiple characteristic guided wave modes, first group velocities corresponding to the multiple characteristic guided wave modes of the detected special-shaped structure are calculated, and a first group velocity matrix is obtained; and inputting the first group velocity matrix into a pre-trained physical information neural network model to obtain the current stress information of the detected special-shaped structure, through the scheme of the embodiment of the invention, the stress information of the special-shaped structure can be calculated through the pre-trained physical information neural network model, and the accuracy of the stress information of the detected special-shaped structure is improved. And high-efficiency and high-precision nondestructive stress measurement is achieved.

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.

This invention discloses an intracavity vortex wave generation device and control method, relating to the field of acoustic engineering technology. The intracavity vortex wave generation device includes a resonant cavity system and a nonlinear control component integrated within the resonant cavity system. The resonant cavity system consists of several resonant units forming a closed loop through a coupling structure to support the resonance of wave modes. The nonlinear control component is used to achieve adjustable non-reciprocal coupling between at least two resonant units. It is also used to generate vortex waves carrying orbital angular momentum by adjusting the coupling parameters of the non-reciprocal coupling. This avoids the complexity and losses of traditional methods that require additional beamforming elements or multiple active transducer arrays. By adjusting the coupling parameters of the non-reciprocal coupling to control the topological charge of the generated vortex waves, vortex waves with different topological charges can be generated, providing wider applicability for various applications.

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 invention discloses an overhead ground wire detection parameter optimization method, system and device based on ultrasonic guided waves and a medium, and the method comprises the steps: analyzing the propagation characteristics of the ultrasonic guided waves of an overhead ground wire based on the related parameters of the overhead ground wire, and calculating the number of initial transducers for obtaining the ultrasonic guided waves; according to the ultrasonic guided wave propagation characteristics of the overhead ground wire, the initial excitation frequency of ultrasonic guided waves is obtained; signal modulation is carried out based on the frequency and time constraint of the ultrasonic guided wave excitation signal, and the initial modulation period number of the ultrasonic guided wave is obtained; and establishing a finite element model of the overhead ground wire, inputting the preliminary transducer number, the preliminary excitation frequency and the preliminary modulation period number into the finite element model, and outputting an optimal parameter combination through multiple times of simulation. By optimizing parameters such as the number of transducers, the excitation frequency and the modulation period for ultrasonic guided wave detection, a low-order axisymmetric longitudinal guided wave mode can be stably excited, high-order mode and noise interference are inhibited, and the detection sensitivity and the positioning precision can be improved.

The invention discloses a pressure pipeline uniform thinning detection method based on multi-mode guided wave fusion. A composite guided wave excitation device is designed to synchronously excite multiple guided wave modes, and high-precision and long-distance wall thickness reduction detection is realized by combining a time-frequency domain conjoint analysis technology and a deep residual network of deep learning.

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 invention discloses a microporous heat dissipation plate detection method, device and equipment based on nonlinear Lamb wave second-order harmonic waves, a medium and a product, and the method comprises the steps: solving a guided wave frequency dispersion curve of a theoretical model of a microporous heat dissipation plate based on a kinetic equation of a Biot porous medium; according to the guided wave frequency dispersion curve, screening modal pairs of guided waves meeting a preset phase velocity matching condition, and determining a guided wave modal based on the modal pairs; based on a multi-physics field coupling finite element model and a guided wave mode, simulating a propagation process of a nonlinear Lamb wave in the microporous heat dissipation plate simulation model, and determining an analogue simulation result; determining effective acoustic time-frequency domain characteristics according to the acoustic time-frequency domain characteristics and the real acoustic time-frequency domain characteristics; establishing a mapping relation between the effective acoustic time-frequency domain characteristics and the internal structure of the microporous heat dissipation plate; based on the mapping relation, a machine learning algorithm and the prediction model, the detection result of the microporous heat dissipation plate is determined, and whether the internal structure of the microporous heat dissipation plate has defects or not is sensitively detected in real time.

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 invention discloses an intra-cavity vortex wave generation device and a control method, and relates to the technical field of acoustic engineering, the intra-cavity vortex wave generation device comprises a resonant cavity system and a nonlinear regulation and control assembly integrated in the resonant cavity system; the resonant cavity system forms a closed loop through a coupling structure by a plurality of resonant units and is used for supporting resonance of a fluctuation mode; the non-linear regulation and control assembly is used for realizing adjustable non-reciprocal coupling between the at least two resonance units; and the resonant cavity system is also used for generating vortex waves carrying orbital angular momentum by adjusting the coupling parameters of the non-reciprocal coupling. The complexity and loss that require additional beamforming elements or multiple active transducer arrays in conventional approaches are avoided. The topological charges of the generated vortex waves are controlled by adjusting the coupling parameters of the non-reciprocal coupling, so that the vortex waves with different topological charges are generated, and wider applicability is provided for various applications.

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 invention belongs to the field of nondestructive testing technology and proposes a full-focus imaging method for axial defects in pipelines based on multi-frame, multi-mode wave fusion. The method employs a detection system consisting of a full-matrix data acquisition instrument, a phased array probe, and angle wedges. Multiple frames of full-matrix data are acquired from different circumferential positions on one side of the pipeline to be inspected. For each reconstruction point within the imaging area, six wave modes are used to perform time-delay superposition and amplitude weighting processing on each frame of acquired full-matrix data. The strongest response from each frame is extracted and fused to reconstruct the contour of the prior unknown axial defect within the pipeline. This method considers the influence of pipeline curvature on ultrasonic wave propagation. By correcting the propagation time calculation, time-delay superposition and amplitude weighting processing, and multi-frame data fusion, it achieves imaging characterization and quantitative detection of prior unknown axial defects within the pipeline.

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.