Tensile-tensile fatigue tests of 16MnR steel sheet specimens with prefabricated flaws were carried out to measure spontaneous stray field signals of stress concentration zones by GMR sensor, and excitation device was used to make external field excitation for sheet specimens. The results showed that the tangential component of stray field signals can still be considered as generalized magnetic memory signals when tests were conducted in external field without load. Magnetic memory signals were strengthened due to external magnetic excitation, improving sensitivity of detection system. The tangential component of stray field signals presented the maximum value at the stress concentration zones, which increased as cycle number increase, and the growth rate isn’t identical in different stages of fatigue damage.
metal magnetic memory; external field; stress concentration zone; 16MnR steel
We would like to thank all the referees for their valuable comments in improving this paper. This research is supported by The Foundation of National Nature Science of China (Grant no.51275048)
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