Feature Extraction of Welding Defects Based on Metal Magnetic Memory

The application of metal magnetic memory testing(MMMT) in weld inspection was investigated. Through experiments, MMMT signals of two samples of being stress free and load imposed were gathered respectively, and comparative analysis was carried out. On the theoretical basis of wavelet packet transform, MMMT signals were processed by wavelet packet decomposition and wavelet energy spectrum analysis. The feasibility of judging the area of defect by the position of energy concentration was proved.