TY - CONF A1 - Kreutzbruck, Marc A1 - Neubauer, Andreas A1 - Pelkner, Matthias A1 - Reimund, Verena T1 - Adapted GMR array used in magnetic flux leakage inspection T2 - 18th WCNDT - World conference on nondestructive testing (Proceedings) N2 - GMR sensors are increasingly used for magnetic surface inspection due to their high sensitivity and high spatial resolution. In case of simple planar or cylindrical shaped components, the GMR-based inspection procedure can be automated easily. In order to reduce the inspection time we present a GMR-based NDT-system consisting of a yoke and a coil as a local magnetization unit. This way the global magnetization step and, if necessary, the corresponding demagnetization cycle can be avoided reducing the number of working steps. Using a local probe we measured plates, bearings, and rails, each of which containing real fatigue cracks and reference artificial cracks of different depths and orientations. Cracks with a depth of 40 ìm could be resolved with a signalto- noise ratio of about 20. A reduction of the measuring time can be obtained using a sensor array. We present an optimized sensor array for nondestructive testing application, where gradiometric arranged GMR layers were fabricated on a board with up to 48 GMR sensors. Each sensor detects the vertical field gradient. In our example the baseline was chosen to be 250 ìm which efficiently suppress external background fields without losing sensitivity for the detection of surface breaking defects. T2 - 18th WCNDT - World conference on nondestructive testing CY - Durban, South Africa DA - 2012-04-16 KW - Flux leakage testing KW - GMR-Sensors KW - Sensor arrays PY - 2012 UR - https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/26351 AN - OPUS4-26351 SN - 978-0-620-52872-6 SP - 1 EP - 8 (Paper 498) AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany