Influence of uniaxial elastic stress on power spectrum and pulseheight distribution of surface Barkhausen noise in pipeline steel

Barkhausen noise (BN) measurements were made on a half-section of a pipe under tensile and compressive isostress. The RMS BN voltage was found to increase with increasing tensile stress and to decrease with increasing compressive stress. Pulse-height distribution analysis and power density spectral analyses were performed on the BN data. These analyses revealed that the BN events with large amplitudes occur in the presence of tensile stress, while events with small amplitude occur under compressive stress. The power of the BN spectrum increased or decreased, respectively, with increasing tension and compression. While the exact mechanism responsible for the shift in BN pulse height distribution is not yet clear, the authors suggest that it may be related to stress-induced changes in domain size, magnetization distribution, and/or the clustering behavior of domain walls