This paper describes the principles of the a.c. field measurement technique, a non-contacting electromagnetic method of crack detection and sizing in metals. The development of the technique is covered, followed by examples of some of the many different applications the technique has been used for, including multi-sensor arrays for rapid manual inspection or for deployment by robotic manipulator in hazardous environments. Finally, recent work on replacing the normal multi-turn coil magnetic field sensors with newly available GMR sensors is discussed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.