Magnetic emission detection of crack initiation

A new technique has been developed to measure the onset of fracture events. Steel structures or facture mechanics steel specimens emit magnetic signals during rapid mechanical loading and when material failure occurs. These signals can be utilized for the detection of the originating events. In particular, the initiation of crack propagation, which is of basic interest for the determination of critical material parameters in fracture mechanics, can be determined. Reported are first results and efforts to understand the origin of the signals by a comparison with fracture surface appearances from fracture mechanics specimens.