TY - JOUR A1 - Reimund, Verena A1 - Blome, Mark A1 - Pelkner, Matthias A1 - Kreutzbruck, Marc T1 - Fast defect parameter estimation based on magnetic flux leakage measurements with GMR sensors N2 - We present a fast inverse scheme that is capable of simultaneously estimating the parameters depth, opening and length for rectangular 3D geometries of surface-breaking defects. The parameter estimation is realized by an iterative least-squares minimization using the trust-region reflective algorithm. A semi-analytic magnetic dipole model that allows the sensor characteristics to be incorporated is used for predicting the stray magnetic fields. Giant magneto-resistance (GMR) measurements were carried out on a test specimen that includes a series of artificial defects. For the estimation of the defect depths relative errors between 0.6% and 15.9% have been obtained. Due to its very low computational costs, the inverse scheme can suitably be employed in automated production environments. KW - Magnetic flux leakage KW - GMR sensor KW - Nonlinear least-squares optimization PY - 2011 U6 - https://doi.org/10.3233/JAE-2011-1391 SN - 1383-5416 SN - 0925-2096 VL - 37 IS - 2-3 SP - 199 EP - 205 PB - IOS Press CY - Amsterdam, The Netherlands AN - OPUS4-24637 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Pelkner, Matthias A1 - Neubauer, Andreas A1 - Blome, Mark A1 - Reimund, Verena A1 - Thomas, Hans-Martin A1 - Kreutzbruck, Marc ED - Chady, T. ED - Gratkowski, S. ED - Takagi, T. ED - Udpa, S.S. T1 - Flux leakage measurements for defect characterization using NDT adapted GMR sensors N2 - High-precision magnetic field sensors are of increasing interest in non destructive testing (NDT). In particular GMR-sensors (giant magneto resistance) are qualified because of their high sensitivity, high signal-to-noise ratio and high spatial resolution. We performed magnetic flux leakage measurements of artificial cracks with a GMR-gradiometer and a 3-axes GMR-magnetometer. Cracks of a depth of 44 μm still could be detected with a sufficient high signal-to-noise ratio. A semi-analytic magnetic dipole model was used for swiftly predicting magnetic stray fields. The reliable reconstruction based on measurements of artificial rectangular-shaped defects is demonstrated. KW - GMR KW - NDT KW - Magnetic flux leakage KW - Reconstruction PY - 2011 SN - 978-1-60750-749-9 SN - 1383-7281 N1 - Serientitel: Studies in applied electromagnetics and mechanics – Series title: Studies in applied electromagnetics and mechanics VL - 35 SP - 217 EP - 224 PB - IOS Press CY - Amsterdam, The Netherlands AN - OPUS4-25374 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc A1 - Thomas, Hans-Martin A1 - Casperson, Ralf A1 - Reimund, Verena A1 - Blome, Mark A1 - Allweins, K. A1 - Lembke, G. ED - Thompson, D.O. ED - Chimenti, D.E. T1 - Magnetic response field of spherical defects within conductive components N2 - The determination of magnetic distortion fields caused by inclusions hidden in a conductive matrix using homogeneous current flow needs to be addressed in multiple tasks of electromagnetic non-destructive testing and materials science. This includes a series of testing problems such as the detection of tantalum inclusions hidden in niobium plates, metal inclusion in a nonmetallic base material or porosity in aluminum laser welds. Unfortunately, straightforward tools for an estimation of the defect response fields above the sample using pertinent detection concepts are still missing. In this study the Finite Element Method (FEM) was used for modeling spherically shaped defects and an analytical expression developed for the strength of the response field including the conductivity of the defect and matrix, the sensor-to-inclusion separation and the defect size. Finally, the results also can be useful for Eddy Current Testing problems, by taking the skin effect into consideration. T2 - 36th Annual Review of Progress in Quantitative Nondestructive Evaluation CY - Kingston, RI, USA DA - 2009-07-26 KW - Electromagnetic testing KW - Spherical defects KW - Finite element method PY - 2010 SN - 978-0-7354-0748-0 SN - 0743-0760 SN - 0094-243X N1 - Serientitel: AIP conference proceedings – Series title: AIP conference proceedings SP - 1 EP - 8 CY - Melville, NY AN - OPUS4-21815 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc A1 - Thomas, Hans-Martin A1 - Casperson, Ralf A1 - Reimund, Verena A1 - Blome, Mark A1 - Allweins, K. A1 - Lembke, G. T1 - Magnetic response field of spherical defects on non-destructive evaluation T2 - NDE 2009 CY - Tiruchirappalli, India DA - 2009-12-10 KW - Electromagnetic testing KW - Spherical defects KW - Finite element method PY - 2009 SP - 271 EP - 275 AN - OPUS4-20831 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Kreutzbruck, Marc A1 - Thomas, Hans-Martin A1 - Casperson, Ralf A1 - Reimund, Verena A1 - Blome, Mark A1 - Allweins, K. A1 - Lembke, G. ED - Mazal, Pavel T1 - Magnetic response field of spherical defects within conductive components T2 - 5th International workshop of NDT experts - NDT in progress 2009 CY - Prague, Czech Republic DA - 2009-10-12 KW - Electromagnetic testing KW - Spherical defects KW - Finite element method PY - 2009 SN - 978-80-214-3968-9 SP - 163 EP - 172 AN - OPUS4-20336 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pelkner, Matthias A1 - Reimund, Verena A1 - Blome, Mark A1 - Thomas, Hans-Martin A1 - Kreutzbruck, Marc T1 - 3D-GMR-Messung an Referenzbauteilen und Rekonstruktion der Rissparameter N2 - Zunehmend werden hochpräzise Magnetfeldsensoren in der Materialprüfung verwendet. Aus dem Zoo der Magnetfeldsensoren eignen sich GMR-Sensoren (Giant Magneto Resistance) aufgrund ihrer hohen Feld- Empfindlichkeit, ihrem hohen Signal-Rausch-Verhältnis sowie ihrer kleinen Sensorflächen (verbunden mit einer hohen Ortsauflösung) hierfür im Besonderen. Mit GMR-Sensoren wurden Risse untersucht und konnten mit einer Tiefe ≤ 50 µm noch mit einem guten Signal-Rausch-Verhältnis aufgelöst werden. Die an Prüfkörpern mit künstlich eingebrachten Defekten gemessenen Streufeldsignale wurden anhand von analytischen Lösungen verifiziert. Anhand der analytischen Lösungen wurden auch Defektparameter zu den aufgezeichneten Signalen rekonstruiert. T2 - DGZfP-Jahrestagung 2010 CY - Erfurt, Deutschland DA - 2010-05-10 PY - 2010 SN - 978-3-940283-26-9 IS - DGZfP-BB 122 (Mo.3.A.4) SP - 1 EP - 9 CY - Berlin AN - OPUS4-21881 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Blome, Mark A1 - Pelkner, Matthias A1 - Reimund, Verena A1 - Kreutzbruck, Marc T1 - Flux leakage measurements for defect characterization using a high precision 3-axial GMR magnetic sensor T2 - 15. ITG/GMA-Fachtagung - Sensoren und Messsysteme 2010 CY - Nürnberg, Deutschland DA - 2010-05-18 PY - 2010 SN - 978-3-8007-3260-9 IS - 151/A6 SP - 809 PB - VDE-Verl. CY - Berlin; Offenbach AN - OPUS4-22963 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -