Detection of stress concentrations around a defect by magnetic Barkhausen noise measurements

The stress distribution around a 50% blind-hole pit in a steel pipe with a 9 mm wall has been studied using high-resolution magnetic Barkhausen noise (MBN) measurements. A magnetic disk read-head is used as the pick up coil in the MBN probe. The study shows a stress concentration factor of similar to 2 at the defect edge perpendicular to the direction of applied stress and similar to-0.6 at the edge parallel to the same. The experimental results are consistent with the analytical solutions obtained by the Airy's stress function approach. (C) 1996 American Institute of Physics.