caa a22 4500 475843185 CHVBK 20180406123906.0 cr unu---uuuuu 170329e20000901xx s 000 0 eng 10.1023/A:1026505625735 doi (NATIONALLICENCE)springer-10.1023/A:1026505625735 Bolt-Hole Corner Crack Inspection Using the Photoinductive Imaging Method [Elektronische Daten] [Cheng-Chi Tai, John Moulder] We applied a laser-excited eddy current (EC) imaging technique, or so-called photoinductive (PI) imaging, to characterize corner cracks at the edge of a bolt hole. Crack images with excellent signal-to-noise-ratios were obtained. The PI signals revealed the geometrical shape of the electrical-discharge-machined (EDM) notches that were either triangular or rectangular. The results show that this technique is promising to characterize the length, as well as possibly the depth and shape, of corner cracks. In this paper we present measurement results of 0.25-mm, 0.50-mm, and 0.75-mm rectangular and triangular EDM notches. We also show measurement results of a very small notch (<0.25 mm) which would be difficult to detect with conventional eddy current techniques. The dependencies of PI signals on laser chopping frequencies and eddy current frequencies are also examined. To demonstrate the photoinductive imaging capabilities to image actual cracks, we display images of fatigue cracks grown in a Ti-6Al-4V hole specimen. Finally, we present comparisons of the photoinductive imaging results with usual eddy current images obtained from a 0.75-mm triangular EDM notch using a rotating bolt-hole scanner. This article intends to verify experimentally that the photoinductive imaging technique has a potential to become a useful nondestructive testing method. Plenum Publishing Corporation, 2000 Photoinductive imaging nationallicence eddy current nationallicence corner crack nationallicence Tai Cheng-Chi Department of Electrical Engineering, National Cheng Kung University Tainan, 701, ROC, Taiwan aut Moulder John Center for Nondestructive Evaluation, Iowa State University Ames, 50011, Iowa, USA aut Journal of Nondestructive Evaluation Kluwer Academic Publishers-Plenum Publishers 19/3(2000-09-01), 81-93 0195-9298 19:3<81 2000 19 10921 https://doi.org/10.1023/A:1026505625735 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1023/A:1026505625735 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Tai Cheng-Chi Department of Electrical Engineering, National Cheng Kung University Tainan, 701, ROC, Taiwan aut NATIONALLICENCE 700 1- Moulder John Center for Nondestructive Evaluation, Iowa State University Ames, 50011, Iowa, USA aut NATIONALLICENCE 773 0- Journal of Nondestructive Evaluation Kluwer Academic Publishers-Plenum Publishers 19/3(2000-09-01), 81-93 0195-9298 19:3<81 2000 19 10921 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer