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 wi th a 9 mm wall has been studied using high-resolution magnetic Barkhau sen 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 direct ion of applied stress and similar to-0.6 at the edge parallel to the s ame. The experimental results are consistent with the analytical solut ions obtained by the Airy's stress function approach. (C) 1996 America n Institute of Physics.