Considerations for the ultrasonic inspection of metal-adhesive bonds usingEMATs

This paper describes some results on the ultrasonic analysis of adhesively bonded aluminium plates using normal incidence radially polarised shear wav e ElectroMagnetic Acoustic Transducers (EMATs). The EMAT system presented h ere has undergone significant development work and improvements compared to previously published examples. ((9,19)) The electronic 'deadtime' of the s ystem has been reduced to approximately 1 microsecond and the frequency ran ge over which measurements can be taken has been extended. The capability o f the technique to detect gross and subtle defects is demonstrated.