Monitoring fatigue damage in materials using magnetic measurement techniques

Abstract

Measurements of hysteresis and Barkhausen effect (BE) have been made on 0.1 wt % C Fe-C alloys subjected to strain-controlled fatigue at various strain amplitudes. A relationship between the fatigue lifetime and strain amplitude was observed. The hysteresis properties of the samples cycled at different strain amplitudes were found to vary systematically with expended fatigue life. These properties showed significant changes in the initial and final stages of fatigue, while between these stages they remained stabilized. In the stable stage the remanence was found to decrease, whereas the coercivity increased with increasing strain amplitude. Variations in BE signal during fatigue were found to be closely related to the microstructural changes observed on the sample surface. These results are interpreted in the context of the changes in microstructure caused by fatigue damage, and the effects of the formation and propagation of fatigue cracks on the field distribution and domain structure in the vicinity of the cracks. Measurements of hysteresis and Barkhausen effect ͑BE͒ have been made on 0.1 wt % C Fe-C alloys subjected to strain-controlled fatigue at various strain amplitudes. A relationship between the fatigue lifetime and strain amplitude was observed. The hysteresis properties of the samples cycled at different strain amplitudes were found to vary systematically with expended fatigue life. These properties showed significant changes in the initial and final stages of fatigue, while between these stages they remained stabilized. In the stable stage the remanence was found to decrease, whereas the coercivity increased with increasing strain amplitude. Variations in BE signal during fatigue were found to be closely related to the microstructural changes observed on the sample surface. These results are interpreted in the context of the changes in microstructure caused by fatigue damage, and the effects of the formation and propagation of fatigue cracks on the field distribution and domain structure in the vicinity of the cracks.

Magnetic response to cyclic fatigue of low carbon Fe-based samples

“…As a result, the p function and hence the value of p(h C ) could increase. This explanation was supported by the results of previous Barkhausen emission measurements made on materials of similar composition [6,20,24] and of different composition [23]. In these studies, a sharp increase in BE signal was observed in the final stage of fatigue.…”

“…Dependence of the traditional magnetic hysteresis parameters (H C , M R and µ IN ) on fatigue of ferromagnetic construction materials (low carbon steel, in particular) may be usually divided into three regions [5,6,9,[20][21][22][23][24].…”

“…In works [6,9,24] where the third region is well seen, the Hall sensor was responsible for the measurement of magnetizing field. In contrast to that, the hysteresis-graph and permeameter setups for this purpose recalculate the field directly from the current which is applied to the solenoid.…”

Exactly solvable model of avalanches dynamics for Barkhausen crackling noise

“…Barkhausen emissions are indeed commonly used to check in a non-destructive way the integrity of magnetic samples: the signal intensity is sensitive to the changes in material microstructure, and to the presence of residual stresses (in magnetostrictive positive materials compressive stresses will decrease the intensity of Barkhausen noise while tensile stresses will increase it). These properties make BN an efficient tool for the detection of micro-imperfections and for the evaluation and mapping of the local distribution of residual stresses [38][39][40][41][42][43][44][45].…”

Utilizing electromagnetic properties to determine the micro-plastic limit of low-carbon steel CSN 411375

“…This research work has mainly been motivated by a desire to determine the correlations between changes in magnetic properties and fatigue characteristics (e.g. [4][5][6][7]). Some work has also been done on utilizing changes in magnetic permeability for studying microplasticity in metals, and for non-destructive investigations of residual stresses in ferromagnetic materials [8][9][10][11][12][13].…”