Analysis of Relationship between Standard Depth of Penetration Skin Effect and Phase Angle of Defect Signal of Eddy Current Testing

와전류(渦電流) 표준침투(標準浸透) 깊이 표피효과(表皮效果)와 결함신호(缺陷信號) 위상각(位相角)의 관계해석(關係解析)

An experiment to investigate the rate of change of phase angle of eddy current output signal caused by outer surface defect of nonferromagnetic tube by variation of standard depth of penetration and variation of percent of tube wall penetration was carried out. The results of the experiment show that the phase angle of defect signal is increased with decreasing the standard depth of penetration or the depth of defect. The results also show that the phase angle is decreased with increasing the skin effect of eddy current, and that the resolution is decreased with decreasing the depth of defect.