Applications of numerical field modeling to electromagnetic methods of nondestructive testing

Electromagnetic field interactions with metals can be used to determine both material properties and the presence of defects. Such techniques are used widely in the nondestructive testing of critical components for aerospace, transportation, energy and metals industries where reliability, safety and product quality considerations are important. This paper describes the common physical basis for active dc, residual and ac methods of specimen magnetization and shows how finite element analysis techniques originally developed for the study of fields in electrical machinery can be extended to predict electromagnetic NDT transducer signals for all three forms of specimen excitation.