Cracks Characterisation by Acoustic and Electromagnetic Emission

Cracks Characterisation by Acoustic and Electromagnetic Emission

Paper in proceedings (conference paper)

The simultaneous investigation of an electromagnetic (EME) and acoustic (AE) emission in solids is described. This method can give additional information on crack creation kinetic and improve crack localisation and its parameters assessment. Granite samples were loaded with a constant stress rate up to their failure and AE and EME signals measured in four channel set-up. Both signals show different behaviour in the first interval of about 10 ms just after crack creation, where high frequency components corresponding to crack walls vibration are dominant, and in the remaining period of about 300 ms where the detected signals time dependence is given mainly by whole sample eigen-vibrations. The EME signal on-set defines exactly the time of crack creation and from the time delay of recorded AE signals the crack position can be determined. The observed high frequency signal of several MHz corresponds to crack length of the order of 1 mm.

The simultaneous investigation of an electromagnetic (EME) and acoustic (AE) emission in solids is described. This method can give additional information on crack creation kinetic and improve crack localisation and its parameters assessment. Granite samples were loaded with a constant stress rate up to their failure and AE and EME signals measured in four channel set-up. Both signals show different behaviour in the first interval of about 10 ms just after crack creation, where high frequency components corresponding to crack walls vibration are dominant, and in the remaining period of about 300 ms where the detected signals time dependence is given mainly by whole sample eigen-vibrations. The EME signal on-set defines exactly the time of crack creation and from the time delay of recorded AE signals the crack position can be determined. The observed high frequency signal of several MHz corresponds to crack length of the order of 1 mm.

Acoustic emission, electromagnetic emission, cracks

Acoustic emission, electromagnetic emission, cracks

ŠIKULA, J., PAVELKA, J., MAJZNER, J., DOBIS, P.

2011

01.09.2002

Czech Society for Non-destructive Testing

Brno

80-214-2174-6

EWGAE 2002 Proceegings

II/164

7

http://hdl.handle.net/