Abstract

This study investigates the sensitivity of Barkhausen noise emission against the stress state as well as microstructure alterations in the steel road barrier flange. The stress state is altered with respect to its residual state after the tensile test, as well as in the tensile and compression regions during the bending test. In order to provide deeper insight into the relationship between stress states, the Barkhausen noise and magnetostriction along two perpendicular directions is measured as well. The microstructure is expressed in terms of the dislocation density altered beyond the yield point. It was found that the increasing yielding during the tensile test reduces the bearing capacity of the flange as well as the notch toughness, and increases the dislocation density. The Barkhausen noise along the flange length exhibits a continuous descent with yielding due to the increased dislocation density, whereas this emission in the perpendicular direction increases due to the realignment of domain walls. The magnetostriction along the flange length is strong and positive, linked with the increasing Barkhausen noise along the flange length due to the tensile stresses, as contrasted against much the weaker magnetostriction along the perpendicular direction and the reversed evolution of the Barkhausen noise. However, the correlation between the MBN and magnetostriction is not straightforward; the systematic evolution of Barkhausen noise alterations as a function of plastic strain is fully missing.

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