A novel nondestructive characterization technique is applied to the ECT monitoring of bilamellar structures as bearing composite cylindrical or conical shells having some protective nonmetallic external coatings. The ECT transducer operation is based on the principle of a transient electric charges reproduction on the two-strip sensory electrodes adjoined to the external medium and placed symmetrically between the high and low potential supply zones of pulsed electric field. Some features of the ECT transducer design and its facilities are considered. A potential field distribution in the layered dielectrical surrounding adjoined to extended coplanar strip electrodes is examined by an integral equation method as a theoretical model which allows to stipulate few useful algorithms for the bilamellar structure parameters monitoring under unilateral access conditions.

REFERENCE

1. K. Nagamatsu et al., "Method and apparatus for defect inspection of liquid-filled insulating container", US Patent N. 4125805 (Int. Cl. GO1R 31/12, GOIN 27/60), 1984