20 results about "Guided wave propagation" patented technology

The invention discloses a parallel simulation method for guided wave focusing imaging of a piezoelectric array of a composite structure, belongs to the technical field of nondestructive testing, and aims at solving the problems that the sound field control precision of a current multi-array-element piezoelectric structure in a composite material plate is insufficient, and a traditional finite element method is large in calculation time consumption, low in convergence speed and high in reliability in the guided wave propagation simulation process. In order to solve the problem that effective convergence cannot be realized under the excitation condition of a high-frequency multi-channel array and even under the excitation condition of a high-frequency multi-channel array, the invention provides an efficient guided wave focusing simulation strategy combining spectral element high-order precision and GPU parallel computing, and the method comprises the following steps: establishing a system control equation considering a piezoelectric-structure coupling effect on the basis of a delay superposition principle; energy focusing and sidelobe suppression of a guided wave signal in a specific direction are realized by adjusting spatial arrangement and excitation time sequence of a piezoelectric array sensor, Gauss-Labatto-Legendre integral nodes are introduced to construct a high-order spectral element unit, unit-level parallel solution is realized under a CUDA architecture, and dynamic simulation capability and overall calculation efficiency of focusing field distribution are remarkably improved.

The invention provides a frequency dispersion curve calculation method based on a decoupling type Legendre-Gauss-Labatto spectral element method, and belongs to the technical field of discrete solution of guided wave propagation in a thin plate, and the method comprises the following steps: S1, constructing a wave equation which comprises a Cartesian space coordinate system based on an orthotropic plate, and combining a constitutive equation, a geometrical relationship under the coordinate system and guided wave displacement to obtain a wave dispersion curve; substituting into a control equation when the volume force is zero to obtain an improved three-dimensional elastic wave equation; s2, a differential matrix is constructed, wherein discretization and decoupling are carried out on a wave equation on the basis of a Lagrange interpolation basis function of a Legendre-Gauss-Labatto node; s3, explicitly embedding the stress free boundary condition into the solving process through matrix line transformation, and solving to obtain a frequency dispersion curve, the derivation process is simplified, the boundary and the interior of the material are decoupled, and the physical significance is clearer. And meanwhile, the high-precision advantage of the spectrum method is maintained, and the calculation rate is remarkably improved.

The invention discloses an overhead ground wire corrosion assessment method, system and device based on ultrasonic guided waves and a medium, and belongs to the technical field of overhead ground wire corrosion assessment, and the method comprises the steps: building a guided wave propagation model of a steel strand, and completing the design of guided wave excitation parameters and sensor arrangement based on the guided wave propagation model; exciting ultrasonic guided waves through an excitation device and performing signal acquisition to obtain a steel strand guided wave propagation signal; carrying out signal preprocessing and feature extraction on the collected guided wave signal; inputting the extracted feature information into a deep learning model to complete identification and evaluation of the corrosion state; and outputting a corrosion position, a corrosion type and a corrosion degree based on an identification result. Compared with the prior art, the method has the advantages that the detection precision, the recognition capability, the adaptability, the anti-interference capability, the intelligent level and the like are obviously superior, and reliable technical guarantee is provided for health monitoring of the overhead ground wire and power grid safety by introducing deep learning, an attention mechanism, transfer learning and a data enhancement strategy.

The invention discloses a construction method of an anchoring anchor rod crack defect guided wave detection numerical model, and belongs to the field of anchor rod nondestructive detection.According to the constructed numerical model, finite element-infinite element coupling is adopted for optimizing the surrounding rock stratum boundary, the problem of boundary multi-reflection echoes caused by artificial boundary truncation is solved, and the detection accuracy is improved. The workload of overall grid division is reduced; the method improves the calculation efficiency while guaranteeing the propagation precision, and effectively simulates the guided wave propagation behavior in the infinite boundary of the surrounding rock stratum. The numerical model constructed by the method is used for detecting the crack of the anchor rod under different defect degrees, so that the defect echo amplitude is in an ascending trend along with the increase of the defect degrees, and the bottom echo amplitude is in a descending trend along with the increase of the defect degrees. The numerical model constructed by the method positions the defect position of the anchor rod crack under different defect degrees, the result shows that the change of the defect degree basically does not influence the positioning of the defect position, the defect position can be accurately positioned through the one-way defect echo and the bottom echo, and the error range is less than or equal to 3%.

The invention discloses an ultrasonic guided wave damage ellipse imaging positioning method and equipment for a layer decreasing composite material laminated plate. The method comprises the following steps: S1, acquiring thickness change direction information of the laminated plate and position coordinates of an excitation transducer and a receiving transducer; s2, according to the material characteristic parameters, simulating and calculating the propagation time of ultrasonic guided waves transmitted from an excitation transducer to any point to generate a first theoretical propagation time map, and simulating and calculating the propagation time of the ultrasonic guided waves transmitted from any point to a receiving transducer to generate a second theoretical propagation time map to generate a second theoretical propagation time map; coupling influence of thickness change and material anisotropy on guided wave propagation is considered in the simulation process; s3, transmitting an ultrasonic guided wave signal, and extracting the actual flight time of a damaged wave packet; s4, calculating theoretical total propagation time, and determining a candidate area where damage exists; and S5, on the basis of repeated operation of the multiple groups of transducer pairs, taking a plurality of candidate region intersections to determine a final damage position. The objective of the invention is to solve the positioning error problem caused by the structural characteristics of a laminated plate in a traditional algorithm, and to realize more accurate damage detection and positioning.

The invention relates to the technical field of image detection, and provides a multi-mode wafer defect detection system. The system comprises a guided wave acquisition module, a stress reconstruction module, a crack database building module, a type identification module and a multi-modal data fusion module, stress distribution information of a crack area is extracted through guided wave propagation parameters, and depth positioning and space calibration of cracks in a multi-layer structure are realized in combination with correction of propagation velocity by temperature. A crack database is constructed by utilizing wave velocity characteristics generated by standardized indentations, a clear mapping relation is established between propagation characteristics and crack types, so that the accuracy of crack property judgment is improved, and the accuracy of crack property judgment is improved by performing spatial registration on a crack recognition result and a stripe abnormal region in an optical interference pattern. Recognition blind areas existing in image detection can be effectively covered, guided wave detection and optical detection results are fused, and the defect coverage range and recognition integrity are enhanced.

The invention provides a performance evaluation method and device of a current transformer, equipment and a medium, and relates to the field of data processing. According to the method, a current transformer is in a saturated edge excitation state through composite working excitation, magnetostriction micro-vibration response signals and guided wave propagation response signals are collected, resonance mode change features, guided wave path propagation features and local scattering features are extracted, and a magnetoacoustic mode feature vector sequence is constructed; inputting the feature vector sequence into a magnetoacoustic-performance mapping model to obtain predicted values of a ratio error, a phase angle error, saturation characteristic offset and a harmonic error, and outputting degradation category probability distribution; and generating a performance attenuation curve and a degradation category evolution track based on the variation trend of each performance predicted value along with time and in combination with degradation category probability distribution, thereby realizing dynamic evaluation of the performance of the current transformer and degradation state judgment. By implementing the technical scheme, the performance evaluation accuracy of the current transformer can be improved.

The invention relates to the technical field of hydrogeological detection, and discloses an ultrasonic guided wave underground water level detection device which comprises an ultrasonic probe shell, a radio frequency assembly is arranged in the ultrasonic probe shell, and a probe rod assembly is arranged at the bottom of the ultrasonic probe shell. The probe rod assembly comprises a longitudinal wave coupling solid rod, a hollow connecting rod, a guided wave propagation hollow rod and a blade foot, the radio frequency assembly comprises an inner layer sleeve, a plurality of wire bundles are arranged in the inner layer sleeve, and the bottom of each wire bundle is fixedly connected with a phased array infinitesimal element. Ultrasonic longitudinal waves are transmitted through a phased array infinitesimal in an ultrasonic probe shell, so that the longitudinal waves repeatedly interfere in a longitudinal wave coupling solid rod to form cylindrical guided waves propagating along the inner wall of a guided wave propagation hollow rod, the cylindrical guided waves propagate to the deep part of a stratum and are reflected by underground water, and the infinitesimal receives and analyzes the propagation time of the reflected waves to calculate the water level depth. The problem that traditional drilling measurement and an electromagnetic method are low in detection efficiency is solved, and the water level detection accuracy and efficiency are improved.

The application provides a performance evaluation method, device and equipment of a current transformer and a medium, and relates to the field of data processing. In the method, the current transformer is in a saturation edge excitation state through composite work excitation, and a magnetostrictive micro-vibration response signal and a guided wave propagation response signal are collected. Resonance modal variation characteristics, guided wave path propagation characteristics and local scattering characteristics are extracted to construct a magnetoacoustic modal feature vector sequence. The feature vector sequence is input into a magnetoacoustic-performance mapping model to obtain a ratio difference, a phase angle error, a saturation characteristic offset and a harmonic error prediction value, and to output a degradation category probability distribution. Based on the change trend of each performance prediction value over time and in combination with the degradation category probability distribution, a performance attenuation curve and a degradation category evolution track are generated, so that dynamic evaluation and degradation state judgment of the performance of the current transformer are realized. Implementation of the technical solution facilitates improvement of the performance evaluation accuracy of the current transformer.

The invention relates to the technical field of nondestructive testing, and particularly provides a fuel rod cladding damage detection method based on multiple diffraction guided wave probability imaging, which comprises the following steps: arranging a pair of signal receiving and transmitting devices at two ends of a to-be-detected area of a fuel rod cladding for transmitting an input signal f (t) and receiving and acquiring wave field data; performing narrowband signal extraction on the obtained wave field data, and extracting a wave packet signal h (t) when frequency dispersion does not occur in each spiral path according to spiral guided wave propagation characteristics; calculating a signal difference coefficient SDC of each spiral path by comparing the difference between f (t) and h (t); calculating the damage probability of each point position in the detection area by using the SDC; and judging the damage probability of all the point positions in the detection area through the damage probability threshold, and determining the damage position. According to the invention, only one pair of signal receiving and transmitting devices is arranged, so that the defects of the scanning area in the fuel rod cladding can be accurately detected and positioned by utilizing spiral guided waves.

The invention discloses a one-way horizontal shearing guided wave electromagnetic ultrasonic excitation device based on a double-V-shaped coil. The device comprises the double-V-shaped coil, a magnet, an electromagnetic shielding shell and a tested workpiece. The double-V-shaped coil is arranged right above a workpiece to be detected, and the magnet is arranged above the coil and packaged in the electromagnetic shielding shell with a downward opening. The double-V-shaped coil is horizontally and symmetrically arranged in an inflection manner; the upper layer coil and the lower layer coil are relatively staggered by 1 / 4 one-way horizontal shearing guided wave wavelength along the horizontal shearing guided wave propagation direction, and 90-degree phase difference excitation is kept; the magnet is composed of four bar magnets which are alternately arranged according to SN poles. The configuration can efficiently excite horizontal shear guided waves which are propagated unidirectionally, improves the detection sensitivity of defects on the surface of a workpiece and near the surface in a specific direction, and is suitable for a scene needing directional selectivity nondestructive detection.

The invention relates to the field of nondestructive testing, in particular to a milling cutter blade defect detection device and method. The method comprises the following steps of: firstly, calculating and drawing a wedge-shaped guided wave propagation group velocity frequency dispersion curve by establishing a milling cutter blade fluctuation mechanical model and adopting a double-Laguerre polynomial series analytical solution method; the optimal excitation frequency for milling cutter blade quality detection is selected according to the group velocity frequency dispersion curve, and implementation of wedge-shaped guided wave quality detection can be efficiently guided. The wedge-shaped guided wave quality detection device of the milling cutter blade is established, noise reduction processing and weak signal extraction are carried out on wedge-shaped guided wave signals obtained through detection, and rapid, convenient and comprehensive health condition detection on the milling cutter blade is facilitated. According to the detection method and device, the optimal excitation frequency of wedge-shaped guided wave quality detection can be efficiently found through a theoretical method, comprehensive quality detection can be conducted on milling cutter blade structures of different specifications through the wedge-shaped milling cutter fixing device, and the signal-to-noise ratio and reliability of quality detection of the milling cutter blade structures are improved.

The invention discloses a battery dendritic crystal monitoring method, system, equipment and product based on ultrasonic guided waves, and the method comprises the steps: employing a piezoelectric transducer to excite SH0 ultrasonic guided waves in a normal charging and discharging state of a battery, and enabling the SH0 ultrasonic guided waves to be transmitted along the surface of an electrode or a waveguide structure which is tightly coupled with the electrode, and high-precision acquisition and analysis are carried out on reflection and transmission echo signals. And carrying out guided wave feature extraction on the echo signal to obtain key parameters such as guided wave propagation time, speed drift and energy attenuation, so as to realize real-time and high-sensitivity monitoring of the process from early stage initiation and growth to irreversible accumulation of the crystal dendrites. And in combination with a signal processing algorithm and a threshold criterion, a quantitative characterization and early warning mechanism of crystal dendrite evolution is constructed, so that the safety risks that the crystal dendrite pierces the diaphragm and internal short circuit occurs are reduced. The nondestructive detection monitoring method can provide powerful technical support for battery safety management, life prediction and battery management system linkage control.

The invention discloses a method for determining guided wave frequency dispersion characteristics of a liquid-filled steel riser, which is characterized in that three-dimensional guided wave propagation is equivalent to a radial one-dimensional intrinsic problem under an axial symmetry condition, a relation between a complex wave number and frequency dispersion can be obtained only by dispersing the radial direction, and high degree of freedom of three-dimensional modeling is avoided. Internal fluid is not coupled through additional boundary terms, and is merged into the overall system by adopting a section contribution matrix, so that fluid-solid consistent assembly in the same system is realized, and error sources of coupling inconsistency are reduced. An external infinite water area does not use an absorption layer for approximation, and external water is equivalent to a wavenumber-related damping boundary by using radiation impedance meeting an infinite radiation condition; and the self-consistent complex wave number is solved through linearization and inverse iteration, so that the radiation modeling accuracy and solvability are improved.

This invention relates to the field of icing and snow accumulation detection technology, and discloses a method and system for detecting icing on overhead transmission lines. The method includes: deploying integrated torsional vibration and acoustic emission sensing units at both ends of the transmission line span to collect conductor angular velocity and acoustic emission signals; performing cross-correlation processing on the angular velocity signals within a time window to obtain the propagation delay of multi-band torsional guided waves, and calculating the group velocity in conjunction with the span length; comparing the group velocity with a baseline curve for an ice-free period, and inverting the icing thickness using a composite pole dispersion model; using the acoustic emission signals to detect sudden events; if the number and energy of events exceed a threshold and the group velocity rebounds, it is determined to be an icing shedding state; otherwise, it enters the thickness and event fusion stage, outputting the icing thickness, growth rate, icing shedding alarm, and confidence level through a confidence factor. This invention can realize dynamic monitoring and early warning of the entire process of icing on transmission lines.

According to the guided wave detection method for the quality of the cast-in-situ bored pile, the ultrasonic transducer is placed on the outer side of the steel casing, and the pouring quality of concrete in the steel casing is detected through vertical propagation of guided waves along the wall of the steel casing, so that the use of a sounding pipe is avoided, the influence of bending and blocking of the sounding pipe is avoided, and the method is more reliable. Meanwhile, by means of the detection method, it can be avoided that a hollow sounding pipe is implanted into the pile foundation, the compactness of the pile foundation can be further improved, and the bearing capacity of the pile foundation is improved. The dispersion effect of the guided waves, namely different propagation speeds of the guided waves with different frequencies, is utilized, and the guided waves with different frequencies are incident to detect dispersion change caused by non-compact concrete pouring. And the overall characterization of the pile is realized.

The application provides a bolt loosening detection method, system and device based on passive flow-induced random guided waves, which has the following steps: a plurality of sensors are pasted on two plates connected by bolts, and random guided wave signals propagated in the plates caused by environmental noise are collected; the collected random guided wave signals are processed by using cross-correlation and band-pass filtering methods; an imaging equation is constructed by using the obtained cross-correlation functions under different filtering frequencies; a to-be-imaged area containing all bolts is divided into discrete grids, each node of the grid is assumed to be a scattering point of guided wave propagation across the plate, the pixel value required for imaging is calculated by using the extracted bolt tightness features, and imaging analysis of the tightness of the multi-bolt structure is realized. The application proposes a guided wave propagation model in the multi-bolt structure, extracts the propagation path and energy information of the passive random guided wave, obtains a multi-bolt tightness imaging method based on delay stacking, and realizes online detection of the tightness of the multi-bolt structure.

The application relates to the technical field of image detection, and provides a multi-modal wafer defect detection system. The system comprises a guided wave collection module, a stress reconstruction module, a crack database construction module, a type identification module and a multi-modal data fusion module. Stress distribution information of a crack area is extracted through guided wave propagation parameters, and the propagation speed is corrected in combination with temperature, so that the depth positioning and spatial calibration of cracks in a multi-layer structure are realized. A crack database is constructed by using the wave speed characteristics generated by standardized indentation, a clear mapping relationship between the propagation characteristics and the crack types is established, the accuracy of crack property determination is improved, the crack identification result is spatially registered with a stripe abnormal area in an optical interference pattern, the identification blind area existing in image detection can be effectively covered, and then the guided wave detection result and the optical detection result are fused, and the defect coverage range and the identification integrity are enhanced.

The invention discloses an anchor rod crack defect nondestructive testing method based on low-frequency ultrasonic guided waves, belongs to the field of anchor rod nondestructive testing, and aims to detect the crack defect degree and defect position of an unanchored anchor rod by using a low-frequency guided wave technology. On one hand, the defect degree is judged, and defects of different degrees have different influences on low-frequency guided waves, so that characteristic parameters such as amplitudes and frequencies of defect reflected waves are changed differently. And the other key point is to accurately judge the position of the defect, due to the influence of the guided wave excitation frequency and the guided wave wavelength characteristic, the error of manual positioning of a wave packet is large, and the specific position of the defect in the anchor rod is judged by analyzing the arrival time of the reflected wave based on the time-distance relationship of guided wave propagation. By deeply analyzing the change rule of the parameters, the defect degree and the defect position are accurately identified.

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.