Lei Mingkai

Bio: Lei Mingkai is an academic researcher. The author has contributed to research in topics: Signal & Phased array ultrasonics. The author has an hindex of 1, co-authored 1 publications receiving 5 citations.

Defect two-dimensional morphology imaging detection method based on multi-mode acoustic beam synthetic aperture focusing

Abstract: The invention discloses a defect two-dimensional morphology imaging detection method based on multi-mode acoustic beam synthetic aperture focusing, belonging to the technical field of nondestructive testing. According to the method, a phased array ultrasonic detector, a phased array ultrasonic probe and a phased array ultrasonic detection system of an oblique wedge block are adopted; and signal acquisition of a detected test block is performed by the electronic scanning function of the phased array ultrasonic detector to obtain A-scanning signal of each aperture of the phased array ultrasonic probe. According to different mode conversion types of excitation acoustic beam of each aperture on the interface between the wedge block and test block, at the bottom of the test block and on the defect surface, proper multi-mode acoustic beam is selected from 8 acoustic beam transmission modes. Based on SAFT imaging principle and Fermat's theorem, the transmission delay of the multi-mode acoustic beam of each aperture is calculated, and amplitudes are overlapped to obtain a reconstructed SAFT image, thus realizing complete representation of defect two-dimensional morphology features. The invention can realize correct recognition of volume type and area type defects so as to realize accurate quantification of defect length, depth and orientation, and has relatively high engineering application value.

Metallic molten pool internal contour online measurement device and method

Abstract: The invention discloses a metallic molten pool internal contour online measurement device and method. The device comprises an excitation assembly, a receiving assembly and a computer for data analysisand control; the excitation assembly comprises a laser, a beam splitter for dividing a beam emitted by the laser into a plurality of beams, and a plurality of sets of array optical fibers for receiving the plurality of beams respectively; and the computer is provided with a dynamic modulation module for dynamically modulating the beam. With the metallic molten pool internal contour online measurement device and method of the invention adopted, metallic molten pool internal contour online measurement can be realized based on a laser ultrasonic phased array detection technology; and a printingprocess can be adjusted according to a detection result, so that high manufacturing quality of parts can be realized.

Ultrasonic defect detection qualitative system and qualitative method

Abstract: The invention provides an ultrasonic defect detection qualitative system and qualitative method that are implemented based on an ultrasonic phased array P-scan imaging device. With the ultrasonic phased array P-scan imaging device, the traditional ultrasonic detection equivalent method can be implemented and the structural defect like an object solder joint defect can be evaluated qualitatively byusing the P scanning imaging technique. For example, for an object solder joint defect, the defect property can be determined by using the P-scan imaging technique based on the morphology features ofthe defect as well as the weld joint groove structure, welding method, and defect position; and thus the morphology of the object defect is reconstructed to achieve a corresponding ultrasonic qualitative detection objective.

Honeycomb sandwich structure detection method based on position-ultrasound signals

Abstract: The invention belongs to the technical field of aviation and aerospace, transportation, construction, non-destructive detection and the like, and relates to a honeycomb sandwich structure detection method based on position-ultrasound signals. According to the honeycomb sandwich structure detection method proposed by the invention, inspectors can simultaneously observe the ultrasonic signals corresponding to each detection position point in each scanning row or column and the changes of the ultrasonic signals on an instrument screen, and then the discrimination of defects and the ultrasonic detection of the honeycomb structure can be carried out more intuitively according to the change of P(x,y)-A(t) signals displayed on the instrument screen. Since the inspectors can simultaneously observethe ultrasonic signals corresponding to each detection position point in each scanning row or column and the changes of the ultrasonic signals on the instrument screen, and then the discrimination ofthe defects and the ultrasonic detection of the honeycomb structure can be carried out more intuitively according to the change of the P(x,y)-A(t) signals displayed on the instrument screen, the difficulty of discriminating the defects is simplified, and thus the accuracy of defect discrimination is improved, the detection rate of the defects is improved, and the misjudgment rate of the defects is reduced.

Fully-focused detection method used for coarse-grained materials and based on phased array ultrasonic flaw detector

Abstract: The invention relates to technical field of non-destructive testing, in particular to a fully-focused detection technology used for coarse-grained material weld joints and based on an M2M phased arrayultrasonic flaw detector. The fully-focused detection technology includes: using the M2M phased array ultrasonic flaw detector as the detection instrument to form a rectangular scanning area on a to-be-detected workpiece, and allowing the scanning area to cover the weld joints and heat affected zone of the to-be-detected workpiece; using M2M instrument detection software to divide the weld jointsand heat affected zone of the to-be-detected workpiece into countless points, focusing each point, and collecting scanning data; using a scanning rack to detect the to-be-detected workpiece, collecting full-weld-joint scanning data, and performing quality evaluation according to related to standards. The detection technology has the advantages that the to-be-detected areas are divided into countless points by using a two-dimensional linear probe, focused detection is performed on each point, the detection sensitivity of the areas can be effectively increased, and effective detection of coarse-grained materials can be achieved; the M2M phased array ultrasonic flaw detector is used to perform optimal algorithm processing on the data, data quantity is reduced, and storage and on-site detection and analysis are facilitated.

Nature determination system and nature determination method for ultrasonically detected defect

Abstract: Disclosed are a nature determination system and nature determination method for an ultrasonically detected defect, the system and method being implemented on the basis of an ultrasonic phased array P-scanning imaging apparatus. By means of the ultrasonic phased array P-scanning imaging apparatus, a traditional ultrasonic detection equivalent method can be implemented, and a structural defect, such as a welding joint defect of an object, can be qualitatively evaluated by means of a P-scanning imaging technique. For example, for a welding joint defect of an object, the nature of the defect can be determined by means of the P-scanning imaging technique according to morphology features of the defect accompanied by a welding groove structure, a welding method, a defect position, etc., such that the morphology of the defect of the object is reconstructed and reproduced so as to achieve a corresponding aim, ultrasonic nature determination detection.