Study On Real-time Inspective Technology Of Copper Strip And Plate’s Internal Defects

3-5mm thick copper is widely used in machinery industry, automotive industry,electronic industry, transportation industry, energy industry, etc. Major accidentscaused by failing to detect the internal defects are not uncommon. Therefore, studyingthe new methods of copper strip and plate’s real-time detection is an urgent need toaddress the key science and technique problems.In this subject, the pulsed eddy current detection method is adopted to study theinternal defects of3-5mm thick copper plate，the main research contents are shown asfollowing:1. Based on summing up the domestic and international development and thedevelopment trend of pulsed eddy current testing technology, the elaboration about theprinciple of pulsed eddy current detection is presented. COMSOL multi-physicssimulation software is used to simulate and analyze how the factors function thesensitivity of pulsed current eddy detection system, such as: the structural parametersof the eddy current probe, excitation frequency, and lift-off height, etc.2. The response model and impedance model of eddy current probe modelinduced by the square wave pulse above copper strip and plate are established, thechange laws between thickness of copper strip and plate, incitation frequency, lift-offheight and impedance, induced voltage of current eddy probe are stimulated by usingMathematica and COMSOL, which verify the correctness of pulsed eddy current fieldanalytical mode.3. There studies the defect quantification method, and develop a pulsed eddycurrent nondestructive testing system aimed to detect the internal defects in3-5mmthick copper strip and plate, and this system is applied to the experimental study ofcrack in3mm thick copper strip and plate. Experimental results show that: this method is adequate in quantifying the surface crack and internal crack which adopts the peak,zero time and peak time of detected signal as eigenvalues, peak and zero-crossing timereflect the information about the volume and deep of crack.The theoretical study of the pulsed eddy current method and the analysis ofexperimental results demonstrate the effectiveness of pulsed eddy current testingmethod on detecting the internal defects in3-5mm thick copper strip and plate, and thefeasibility of quantitative methods, the predetermined aims have been completed.