Research on the Crack Detection of Conductive Components Using Pulsed Eddy Current Thermography

Crack of conductive component is one of the biggest threats to daily production. In order to detect the crack on conductive component,the pulsed eddy current thermography models were built according to different materials with the cracks based on finite element method(FEM) simulation. The influence of the induction heating temperature distribution with the different defect depths were simulated for the carbon fiber reinforced plastic(CFRP) materials and general metal materials. The grey value of image sequence was extracted to analyze its relationship with the depth of crack. Simulative and experimental results show that in the carbon fiber reinforced composite materials,the bigger depth of the crack is,the larger temperature rise of the crack during the heating phase is; and the bigger depth of the crack is,the faster the cooling rate of the crack during the cooling phase is. In general metal materials,the smaller depth of the crack is,the lager temperature rise of the crack during the heating phase is; and the smaller depth of the crack is,the faster the cooling rate of crack during the cooling phase is.

Feature Extraction Approach for Defect Inspection in Eddy Current Pulsed Thermography

The eddy current pulsed thermography(ECPT)technique is a research focus in the non-destructive testing(NDT)area for defect inspection.Defect feature extraction for defect information analysis in ECPT is limited by image contrast,heat diffusion,background interference,etc.In this paper,a defect feature extraction approach in ECPT has been proposed to improve the quality of defect features,which is based on image partition,local sparse component evaluation,and feature fusion.This method can extract complete defect features by enhancing the defect area and removing background interference,such as noises and heating coil.Two typical steel specimens are utilized to testify the validity of the proposed approach.Compared with other three common feature extraction algorithms in ECPT,the proposed method can reserve more complete defect features and suppress more background interference.

Pulsed electromagnetic non-destructive evaluation and applications

This paper introduces recent research work in the field of pulsed electromagnetic non-destructive testing/evaluation.These are pulsed eddy current,pulsed magnetic flux leakage and eddy current pulsed thermography.This paper introduces pulsed electromagnetic techniques and their different case studies on defect detection as well as stress characterisation.Experimental tests have been validated and future research plans are discussed.This paper demonstrates pulsed electromagnetic non-destructive testing and evaluation for not only depth information,but also for multiple parameter measurement and multiple integration,which are important for future development.