The Detection Methods Of Internal Defects Of Aluminum Plate Based On Pulsed Eddy Current

The pulsed eddy current testing technology is based on the principle of electromagnetic induction,used to detect defects in conductive materials.The principle of pulsed eddy current testing is basically the same as traditional eddy current testing,the main differences are the incentive mode and the signal analysis method.As the defects of the metal materials,they may cause huge loss no matter it is on the surface or inside.The defects on the metal surface are relatively easy to find,but the defects hidden in the metal are hard to detect.To solve this problem,the paper's main study is to find the pulsed eddy current testing method of aluminum plate's internal defect.The background of the project and the research status of pulsed eddy current testing technology at home and abroad are introduced in this paper.The basic electromagnetic principle of pulsed eddy current testing method is discussed.The effects of aluminum plate's internal defect on magnetic field are analyzed by Comsol simulation.The extraction and treatment mechanism of signal is described.The characteristics and algorithms of butterworth low pass filter are analyzed.In order to find the relationship between aluminum plate's defect and the detection signals,the samples are designed specifically,then the probe construction is designed by using Comsol.The reasonable testing way is designed after analyzing.In order to find the characterization method of aluminum plate's internal defect through experiments.A new characteristic quantity to locate the internal defect is designed.That is the intersection time between the defect signal and the reference signal.The peak value of the voltage signal can represent the defect depth as a characteristic quantity.A set of experimental methods which can represent the aluminum plate's internal defects is developed successfully.