PSI - Issue 16

Valentyn Uchanin et al. / Procedia Structural Integrity 16 (2019) 198–204 Valentyn Uchanin, Giuseppe Nardoni / Structural Integrity Procedia 00 (2019) 000 – 000

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Fig. 3. EC probe signals obtained by inspection through (a) 0.5 mm; (b) 1.0 mm and (c) 1.5 mm thick aluminum plates.

3. Development and investigation of array type EC probe for one-channel flaw detectors

New array type EC probe (named as EDDYLINE 5/12) for one-channel flaw detectors was developed for inspection productivity enhancement. Developed probe consists of 5 separate EC probes connected by specially developed matching unit for summarizing the signal responses of each separate EC probes (Fig. 4). All separate EC probes are realized by double differential scheme for better noise suppression (Uchanin (2013)). Due such connection high sensitivity area with length about 60 mm was achieved. At the same time, high inspection locality was provided, because each of separate EC probes is operated individually with the same sensitivity as before connection.

Fig. 4. The scheme of array type EC probe operated with one-channel flaw detector: 1 – array EDDYLINE type EC probe; 2 … 6 – set of separate EC probes; 7 – matching unit; 8 – connecting cable; 9 – flaw detector; 10 – inspected object; 11 – crack.

The investigations were carried out with the same reference standard application as in section 2.1. Fig. 5a show the signals of array type EC probe from shallowest 0.1 and 0.2 mm depth slots in situation when only one separate EC probe was scanned across the slot area. At this time other 4 probes were situated out of specimen (in the air). Next figure (Fig. 5b) show the signals of the same slots when two of separate EC probes were scanned across the flaw area simultaneously. Fig. 5c show the signals of the same slots when three of separate EC probes were scanned across the slot area at the same time. It is clear that each of additional separate EC probe scanned across the long crack increase the signal amplitude proportionally to the number of EC probes transferred across the crack area.

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Fig. 5. Array type EC probe signals in complex plane for (a) one, (b) two and (c) three EC probes were scanned across the 0.1 and 0.2 mm deep slots.