Novel Method for Sizing Metallic Bottom Crack Depth Using Multi-frequency Alternating Current Potential Drop Technique

Measurement Science Review

Wan Zhengjun¹  Li Yuting¹  Li Wenqiang¹  Gan Fangji¹  Liao Junbi¹ 

[1] School of Manufacturing, Science and Engineering, Sichuan University, Chengdu, Sichuan province, 610065, P. R. China;

关键词: Nondestructive testing;    alternating current potential drop technique;    bottom crack;    depth measurement;   

DOI  :  10.1515/msr-2015-0037

来源: DOAJ

【 摘 要 】

Potential drop techniques are of two types: the direct current potential drop (DCPD) technique and alternating current potential drop (ACPD) technique, and both of them are used in nondestructive testing. ACPD, as a kind of valid method in sizing metal cracks, has been applied to evaluate metal structures. However, our review of most available approaches revealed that some improvements can be done in measuring depth of metal bottom crack by means of ACPD, such as accuracy and sensitivity of shallow crack. This paper studied a novel method which utilized the slope of voltage ratio-frequency curve to solve bottom crack depth by using a simple mathematic equation based on finite element analysis. It is found that voltage ratio varies linearly with frequency in the range of 5-15 Hz; this range is slightly higher than the equivalent frequency and lower than semi-permeable frequency. Simulation and experiment show that the novel method can measure the bottom crack depth accurately.

【 授权许可】

Unknown