Passive piezomagnetic monitoring of structures subjected to in-service cyclic loading: Application to the detection of fatigue crack initiation and propagation

In this research, the evolution of the piezomagnetic field of a low carbon steel under cyclic tensile stress was investigated. The objective was to explore the correlations between piezomagnetic signal measured by a fluxgate magnetometer with progressive changes that take place during the fatigue tests. Experiments show first that the piezomagnetic hysteresis loop changes drastically with the propagation of fatigue crack. A multiscale magneto-elastic model of the piezomagnetic behavior allows secondly the experimental cycles evolution to be explained.