Four novel nondestructive evaluation techniques

This chapter describes new techniques to decrease the inspection time and increase the probability of detection of small defects. The techniques are the Line-On-Line Eddy Current (LOLEC), the Magneto-Elastic Defect Illuminator (MEDI), the Scanning Electro-Elastic Line (SEEL), and the Scanned Electrodynamic Transduction (SET). The LOLEC concept involves the generation of eddy currents in the material being tested with a straight long wire. MEDI transforms defects into sound sources from the interaction of eddy currents generated at crack edges with a properly oriented magnetic field. The SEEL is a self-scanning linear probe which can determine in real time the presence, location, number, and size of defects present along a linear path on the surface of a conductive material being tested. The SET uses long electrical wires or printed-circuit patterns permanently bonded to the structure (or temporarily taped). It is determined that LOLEC provides the shortest inspection time and the highest spatial resolution possible with an eddy current method