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: An imaging method and an imaging apparatus based on a magnetic flux leakage testing. The imaging method includes: selecting an imaging region having a corrosion defect on a pipeline to be tested; dividing the imaging region into a plurality of grid areas; scanning by a three-dimensional sensor array the pipeline to be tested so as to obtain magnetic flux leakage testing data; creating a three-dimensional orthogonal coordinate system in the imaging region, defining a first two-dimensional matrix of defect images according to the plurality of grid areas based on the three-dimensional orthogonal coordinate system, and creating a second two-dimensional matrix of magnetic flux leakage signals according to the magnetic flux leakage testing data based on the three-dimensional orthogonal coordinate system; and mapping the second two-dimensional matrix to the first two-dimensional matrix using a pre-trained wavelet neural network so as to image the corrosion defect.

Abstract: An inner detecting device for subsea oil and gas pipeline includes a support shaft defining a sealed chamber therein; a packer cup coupled to the support shaft; a hinge assembly coupled to the support shaft, swinging with respect to the support shaft in a radial direction and sliding with respect to the support shaft in an axial direction; a magnetic detector connected to the hinge assembly to move with respect to the support shaft in the radial and axial directions, and the magnetic detector tending to move away from the support shaft in the radial direction; a battery pack; an electric recorder electrically connected to the battery pack; and a mileage recorder recording a travel distance of the inner detecting device within the pipeline.

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 Rm1, 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: 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: 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: A method and apparatus for quantifying a pipeline defect based on a magnetic flux leakage testing are provided. The method includes: performing a magnetic flux leakage testing on a pipeline to be tested so as to obtain three-dimensional magnetic flux leakage testing data of the pipeline to be tested; and quantifying a defect on the pipeline to be tested according to the three-dimensional magnetic flux leakage testing data of the pipeline to be tested and a pre-established quantization formula, so as to obtain a size and distribution of the defect.

Abstract: An imaging method and an imaging apparatus based on a magnetic flux leakage testing. The imaging method includes: selecting an imaging region having a corrosion defect on a pipeline to be tested; dividing the imaging region into a plurality of grid areas; scanning by a three-dimensional sensor array the pipeline to be tested so as to obtain magnetic flux leakage testing data; creating a three-dimensional orthogonal coordinate system in the imaging region, defining a first two-dimensional matrix of defect images according to the plurality of grid areas based on the three-dimensional orthogonal coordinate system, and creating a second two-dimensional matrix of magnetic flux leakage signals according to the magnetic flux leakage testing data based on the three-dimensional orthogonal coordinate system; and mapping the second two-dimensional matrix to the first two-dimensional matrix using a pre-trained wavelet neural network so as to image the corrosion defect.

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: An inner detecting device for subsea oil and gas pipeline includes a support shaft defining a sealed chamber therein; a packer cup coupled to the support shaft; a hinge assembly coupled to the support shaft, swinging with respect to the support shaft in a radial direction and sliding with respect to the support shaft in an axial direction; a magnetic detector connected to the hinge assembly to move with respect to the support shaft in the radial and axial directions, and the magnetic detector tending to move away from the support shaft in the radial direction; a battery pack; an electric recorder electrically connected to the battery pack; and a mileage recorder recording a travel distance of the inner detecting device within the pipeline.

Abstract: An apparatus for detecting magnetic flux leakage signals is provided. The apparatus includes: M three-axis magnetic field sensors configured to detect a three-dimensional magnetic field intensity in M locations respectively to obtain M three-dimensional magnetic field intensity data, in which M is an integer larger than three; a field programmable gate array configured to receive and process the M three-dimensional magnetic field intensity data respectively; a main control chip configured to receive and pack the processed M three-dimensional magnetic field intensity data; and a data output interface configured to output the packed M three-dimensional magnetic field intensity data.