The analysis of magnetic Barkhausen noise (MBN) has been used to provide information about the stress state and microstructural properties of ferromagnetic materials. Recent work has shown that a technique using acoustic Barkhausen noise (ABN) detection can provide the similar capabilities as traditional MBN along with additional information for defect characterisation and thickness measurement in a single system. Because the detection of ABN using a piezoelectric sensor can be carried out at any point on the material surface, as well as analysing ABN for microstructural characterisation, the interaction of the surface propagating waves with defects can also be analysed and used for defect characterisation, along with frequency analysis for thickness measurement. As with electromagnetic acoustic transducer (EMAT) systems, the ABN technique applies totally different physical principles to traditional ultrasonic methods and couplant is not needed for excitation. The work is carried out through experimental investigations of calibrated steel samples with machined defects using the ABN system, in comparison to readings taken using an EMAT system. Test results show that the ABN technique has potential applications in providing a comprehensive system for material and stress characterisation along with the additional capabilities of defect characterisation and material thickness measurement.
IOS Press, Inc.
6751 Tepper Drive
Clifton, VA 20124
Tel.: +1 703 830 6300
Fax: +1 703 830 2300 email@example.com
(Corporate matters and books only) IOS Press c/o Accucoms US, Inc.
For North America Sales and Customer Service
West Point Commons
Lansdale PA 19446
Tel.: +1 866 855 8967
Fax: +1 215 660 5042 firstname.lastname@example.org