Abstract: A device and a method for testing a steel defect based on internal and external magnetic perturbation. The device includes: a magnetizer comprising a magnetization source and a magnet yoke, arranged on a surface of a sample, and configured to generate two types of typical magnetic field regions applied to testing based on internal and external magnetic perturbation; a double-row magnetic sensor probe, configured to collect internal and external magnetic perturbation data; a master controller, configured to perform pre-processing on the internal and external magnetic perturbation data, and store the pre-processed data; scanner wheels, configured to generate a sampling trigger pulse during scanning to enable the master controller to receive the internal and external magnetic perturbation data from the probes; and a host computer, configured to analyze the pre-processed data uploaded by the master controller to obtain a defect quantitative result.

Abstract: The present disclosure provides a device and a method for testing a steel defect based on internal and external magnetic perturbation. The device includes: a magnetizer comprising a magnetization source and a magnet yoke, arranged on a surface of a sample, and configured to generate two types of typical magnetic field regions applied to testing based on internal and external magnetic perturbation; a double-row magnetic sensor probe, configured to collect internal and external magnetic perturbation data; a master controller, configured to perform pre-processing on the internal and external magnetic perturbation data, and store the pre-processed data; scanner wheels, configured to generate a sampling trigger pulse during scanning to enable the master controller to receive the internal and external magnetic perturbation data from the probes; and a host computer, configured to analyze the pre-processed data uploaded by the master controller to obtain a defect quantitative result.

Abstract: A device and a method for detecting a defect contour with omnidirectionally equal sensitivity based on magnetic excitation are provided. The device includes a magnetic sensor array arranged in a spatially uniform magnetic field and configured to collect a magnetic field signal, and a data analysis module configured to analyze the magnetic field signal, extract a distorted magnetic field signal, and obtain an image of the defect contour based on the distorted magnetic field signal.

Abstract: The present disclosure provides a method and a device for detecting and evaluating a defect with electromagnetic multi-field coupling. The method includes magnetizing a pipeline with the electromagnetic multi-field coupling; detecting a defect of the pipeline along an axial direction of the pipeline at a constant speed; collecting signals at a position of the defect to obtain magnetic leakage signals in three dimensions and an electrical impedance signal; pre-processing the collected signals; decoupling the pre-processed signals, to obtain decoupled magnetic leakage signals and a decoupled electrical impedance signal; performing impedance analysis on the decoupled electrical impedance signal, and determining a type of the defect based on a phase angle of the decoupled electrical impedance signal; and performing quantification analysis on the decoupled magnetic leakage signals and performing quantification evaluation on a size of the defect using a neural network defect quantification method.

Abstract: A device and a method for detecting a defect contour with omnidirectionally equal sensitivity based on magnetic excitation are provided. The device includes a magnetic sensor array arranged in a spatially uniform magnetic field and configured to collect a magnetic field signal, and a data analysis module configured to analyze the magnetic field signal, extract a distorted magnetic field signal, and obtain an image of the defect contour based on the distorted magnetic field signal.

Abstract: Disclosed are a method and device for compressing and reconstructing data. The method includes: disposing a transmitting EMAT array and a receiving EMAT array; exciting a Lamb wave, receiving the Lamb wave, subjecting the Lamb wave to narrowband filtering with the narrowband frequency, to form detecting data x(n); analysing the detecting data with a DFT; reconstructing original detecting data and calculating a reconstruction error according to the measurement vector and the recovery matrix by using a TLBO algorithm; optimizing measurement vector and recovery matrix; transmitting the measurement vector to a supervisory device.

Abstract: A method for reconstructing a defect includes: S1, establishing a database of magnetic flux leakage signals of a unit defect and acquiring a magnetic flux leakage signal of the unit defect; S2, acquiring a target magnetic flux leakage signal; S3, initially setting a scaling factor k; S4, constructing a forward model; S5, inputting the k into the forward model and performing forward prediction according to the k to acquire a predicted magnetic flux leakage signal for the defect to be detected; S6, calculating an error between the target magnetic flux leakage signal and the predicted magnetic flux leakage signal, and determining whether the error is smaller than an error threshold ?, if yes, executing S7; otherwise, executing S5 after the k is corrected; and S7, scaling the unit defect according to the k to acquire a final size of the defect to be detected.

Abstract: A method for identifying a defect opening profile includes: acquiring a vertical component of a magnetic flux leakage signal of a defect; identifying right-angle features and corresponding right-angle position points of the defect from the vertical component; obtaining all possible right-angle types at each right-angle position point of the defect according to the corresponding right-angle feature of the vertical component; traversing all the possible right-angle types at each right-angle position point to determine respective optimal right-angle type at each right-angle position point; and drawing the defect opening profile according to the respective optimal right-angle type at each right-angle position point.

Abstract: A method for detecting a defect of a metal plate includes selecting N controllable emitting electromagnetic acoustic transducers EMATs as excitation transducers, and selecting M omnidirectionally receiving EMATs as receiving transducers, exciting an ultrasonic guided wave in a metal plate by a nth controllable emitting EMAT with a predetermined emission angle; determining whether each of M1 omnidirectionally receiving EMATs and the nth controllable emitting EMAT form a scattering group; for the scattering group, solving a position of a scattering point and a direction of a scattering side according to a distance between Tn and Rml, the emission angle and a travel time of the ultrasonic guided wave; performing a curve fitting on all the scattering points in directions of respective scattering sides to obtain a contour image of the defect.

Abstract: The present disclosure provides a device and method for detecting a defect in a main shaft of a wind turbine. The device includes: an excitation source, configured to generate an electromagnetic ultrasonic guided wave signal; a nickel strap, magnetized and disposed on an outer surface of an end of the main shaft; a coil, disposed at the nickel strap, configured to receive the electromagnetic ultrasonic guided wave signal such that the electromagnetic ultrasonic guided wave signal propagates in the main shaft, the coil and the nickel strap being configured to transform the electromagnetic ultrasonic guided wave signal propagating in the main shaft into an electrical signal by electromagnetic induction; a signal collector, configured to collect the electrical signal and transform the electrical signal into guided wave detection data and a wireless communication component, configured to transmit the guided wave detection data to a remote equipment.

Abstract: The present disclosure provides a method and a device for detecting and evaluating a defect with electromagnetic multi-field coupling. The method includes magnetizing a pipeline with the electromagnetic multi-field coupling; detecting a defect of the pipeline along an axial direction of the pipeline at a constant speed; collecting signals at a position of the defect to obtain magnetic leakage signals in three dimensions and an electrical impedance signal; pre-processing the collected signals; decoupling the pre-processed signals, to obtain decoupled magnetic leakage signals and a decoupled electrical impedance signal; performing impedance analysis on the decoupled electrical impedance signal, and determining a type of the defect based on a phase angle of the decoupled electrical impedance signal; and performing quantification analysis on the decoupled magnetic leakage signals and performing quantification evaluation on a size of the defect using a neural network defect quantification method.

Abstract: A method for adjusting array of omnidirectional EMATs includes: uniformly arranging N EMATs in a detection region of a metal plate; calculating positions of scattering points according to amplitudes and travel times of guided wave scattering signals, and forming a first defect profile curve by performing three smooth spline interpolations on coordinate data of positions of scattering points; calculating curvatures of points on the first defect profile curve by solving a first and second derivatives of a function of the first defect profile curve; determining an array adjustment region by comparing the curvature with a preset threshold, adjusting the array and calculating a second defect profile curve; and performing data fusion on the first and second defect profile curves to form a defect profile image of the metal plate.

Abstract: An imaging method based on guided wave scattering of omni-directional EMATs includes: selecting an nth omni-directional EMAT from N omni-directional EMATs uniformly arranged in a detection region of a metal plate to be detected as an excitation EMAT; selecting m omni-directional EMATs as omni-directionally receiving EMATs to omni-directionally receive an ultrasonic guided wave signal, and calculating a travel time and intensity of the ultrasonic guided wave signal; judging whether the excitation EMAT and the omni-directionally receiving EMATs form a scattering group, if yes, calculating a position of a scattering point; judging whether the position of the scattering point is within a preset scattering region, if yes, determining the position of the scattering point as an effective scattering point; repeating the above steps until all N omni-directional EMATs have excited omni-directional ultrasonic guided waves, and performing curve fitting on all effective scattering points to obtain a defect profile image.

Abstract: A high-precision imaging and detecting device for detecting a small defect of a pipeline by a helical magnetic matrix. The device includes: a helical excitation module including a helical excitation coil; a magnetic matrix detection module, disposed at an inner side of the helical excitation coil and including at least one magnetic sensor group arranged at intervals along an axial direction of the helical excitation coil, group including a plurality of magnetic sensors evenly spaced apart and arranged along a circumferential direction of the helical excitation coil, and the magnetic sensor being configured to detect an induction magnetic field of the pipeline; a signal processing module, connected with the magnetic matrix detection module, and configured to receive, process and output an induction magnetic field signal of the pipeline detected by the magnetic sensor.

Abstract: A method for identifying a defect opening profile includes: acquiring a vertical component of a magnetic flux leakage signal of a defect; identifying right-angle features and corresponding right-angle position points of the defect from the vertical component; obtaining all possible right-angle types at each right-angle position point of the defect according to the corresponding right-angle feature of the vertical component; traversing all the possible right-angle types at each right-angle position point to determine respective optimal right-angle type at each right-angle position point; and drawing the defect opening profile according to the respective optimal right-angle type at each right-angle position point.

Abstract: Disclosed are a method and a device for testing a defect based on an ultrasonic Lamb wave tomography. The method includes: partitioning an imaging area of a material to be tested into grids; exciting electromagnetic acoustic transducers for emitting to emit Lamb waves with a A0 mode in all directions, and electromagnetic acoustic transducers for receiving to receive the Lamb waves; obtaining a time-frequency analysis result and recording time-of-flights of testing waves; determining a first slowness of each grid to obtain a first defect area; establishing an extrapolation formula according to the first defect area, and iterating the extrapolation formula to trace and revise paths of the Lamb waves until a better imaging precision is obtained.

Abstract: A high-precision imaging and detecting device for detecting a small defect of a pipeline by a helical magnetic matrix. The device includes: a helical excitation module including a helical excitation coil; a magnetic matrix detection module, disposed at an inner side of the helical excitation coil and including at least one magnetic sensor group arranged at intervals along an axial direction of the helical excitation coil, group including a plurality of magnetic sensors evenly spaced apart and arranged along a circumferential direction of the helical excitation coil, and the magnetic sensor being configured to detect an induction magnetic field of the pipeline; a signal processing module, connected with the magnetic matrix detection module, and configured to receive, process and output an induction magnetic field signal of the pipeline detected by the magnetic sensor.

Abstract: The method for calculating an MFL signal of a defect includes: determining sizes l0, w0 and d0 of an element defect according to sizes l, w and d of a target defect, acquiring an MFL signal HE (x, y, z) of the element defect; subjecting the MFL signal HE(x, y, z) to a three-dimensional Fourier transformation to acquire a frequency domain signal FE(?, ?, ?); subjecting the FE(?, ?, ?) to a translation transformation in the magnetization direction to acquire two frequency domain signals FE??(?, ?, ?) and FE?+(?, ?, ?); combining the FE??(?, ?, ?) and FE?+(?, ?, ?) to acquire a combined frequency domain signal FEcombine(?, ?, ?); subjecting the combined frequency domain signal FEcombine(?, ?, ?) to a three-dimensional inverse Fourier transformation to acquire an MFL signal HT(x, y, z) of the target defect.

Abstract: A method for reconstructing a defect includes: S1, establishing a database of magnetic flux leakage signals of a unit defect and acquiring a magnetic flux leakage signal of the unit defect; S2, acquiring a target magnetic flux leakage signal; S3, initially setting a scaling factor k; S4, constructing a forward model; S5, inputting the k into the forward model and performing forward prediction according to the k to acquire a predicted magnetic flux leakage signal for the defect to be detected; S6, calculating an error between the target magnetic flux leakage signal and the predicted magnetic flux leakage signal, and determining whether the error is smaller than an error threshold ?, if yes, executing S7; otherwise, executing S5 after the k is corrected; and S7, scaling the unit defect according to the k to acquire a final size of the defect to be detected.

Abstract: A method for adjusting array of omnidirectional EMATs includes: uniformly arranging N EMATs in a detection region of a metal plate; calculating positions of scattering points according to amplitudes and travel times of guided wave scattering signals, and forming a first defect profile curve by performing three smooth spline interpolations on coordinate data of positions of scattering points; calculating curvatures of points on the first defect profile curve by solving a first and second derivatives of a function of the first defect profile curve; determining an array adjustment region by comparing the curvature with a preset threshold, adjusting the array and calculating a second defect profile curve; and performing data fusion on the first and second defect profile curves to form a defect profile image of the metal plate.