Events
COMPARISON OF ELECTROMAGNETIC RADIATION (EMR) EMITTED DURING COMPRESSION AND PERCUSSION DRILLING OF BRITTLE MATERIALS
00:00 17-09-2006
The work presented contains theoretical and experimental study of EMR emitted from cracks propagating in brittle materials. Experiments were carried out for fracture by compression and percu- ssion drilling. EMR signals have been analysed using the theoreti- cal model of Rabinovitch et al, which ascribes EMR to the oscillat- ion of ions at the developing crack sides and predicts that EMR should have the shape of oscillating pulses. It has been shown, among others, that (i) EMR intensity is not affected by fracture
mode (tensile or shear); (ii) crack area is proportional to the
ratio of the pulse growth time and its frequency; (iii) rise and
fall time of the pulses is determined by the crack width and tempe- rature; (iv) polarization falloff is another EMR source not inclu- ded in the model.