TY - CONF A1 - Kreutzbruck, Marc T1 - Phased Array-Based SAFT for Defect Sizing on Power Plant Components T2 - 35th Annual Review of Progress in Quantitative Nondestructive Evaluation (QNDE) CY - Chicago, IL, USA DA - 2008-07-20 PY - 2008 AN - OPUS4-18110 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kreutzbruck, Marc A1 - Lembke, G. A1 - Mogwitz, B. A1 - Korte, C. A1 - Janek, J. T1 - Linear magnetoresistance in Ag2+deltaSe thin films N2 - In the nonstoichiometric low-temperature phase of silver selenide a very small silver excess within the semiconducting silver selenide matrix in the order of 0.01% is sufficient to generate a linear magnetoresistance (LMR) of more than 300% at 5 T, which does not saturate at fields up to 60 T. Different theoretical models have been proposed to explain this unusual magnetoresistance (MR) behavior, among them a random resistor network consisting of four-terminal resistor units. According to this model the LMR and the crossover field from linear to quadratic behavior are primarily controlled by both the spatial distribution of the charge-carrier mobility and its average value, being essentially functions of the local and average compositions. Here we report measurements on silver-rich thin AgxSe films with a thickness between 20 nm and 2 µm, which show an increasing average mobility in conjunction with an enhanced MR for increasing film thickness. We found a linear scaling between the size of the transverse LMR and the crossover field, as predicted by the theory. For films thinner than about 100 nm the MR with field directed in the sample plane shows a breakdown of the LMR, revealing the physical length scale of the inhomegeneities in thin AgxSe devices. KW - Carrier mobility KW - Magnetoresistance KW - Semiconductor materials KW - Semiconductor thin films KW - Silver vompounds KW - Stoichiometry PY - 2009 DO - https://doi.org/10.1103/PhysRevB.79.035204 SN - 1098-0121 SN - 0163-1829 SN - 0556-2805 SN - 1095-3795 SN - 1550-235X VL - 79 IS - 3 SP - 035204-1 - 035204-5 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-18930 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - GMR sensors for Nondestructive Testing - Recent Developments in Sensor based Eddy Current and Magnetic Flux Leakage Testing T2 - 10th Symposium Magnetoresistive Sensors and Magnetic Systems CY - Wetzlar, Germany DA - 2009-03-31 PY - 2009 AN - OPUS4-19038 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kienle, L. A1 - Duppel, V. A1 - Mogwitz, B. A1 - Korte, C. A1 - Kreutzbruck, Marc A1 - Janek, J. T1 - Real structures and structural modifications of Ag2+xSe thin films KW - Ag clusters KW - MR KW - LT PY - 2007 DO - https://doi.org/10.1017/S1431927607082013 SN - 1431-9276 SN - 1435-8115 VL - 13 IS - Suppl 3 SP - 402 EP - 403 PB - Cambridge University Press CY - New York, NY AN - OPUS4-19242 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - Advanced Crack Shape Analysis Using SAFT T2 - Non-destructive Evaluation 2009, Non-destructive Evaluation in Power Industry CY - Tiruchirappalli, India DA - 2009-12-10 PY - 2009 AN - OPUS4-20058 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kervalishvili, Guram N. A1 - Schlichting, Joachim A1 - Maierhofer, Christiane A1 - Kreutzbruck, Marc T1 - FEM modelling of heat transfer in the vicinity of vertical surface cracks using local thermal excitation T2 - Thermographie-Kolloquium 2009 CY - Stuttgart, Germany DA - 2009-10-08 KW - FEM modelling KW - Active thermography KW - Laser excitation KW - Cracks KW - Steel PY - 2009 IS - DGZfP-BB 119-CD (Poster 02) SP - 1 EP - 8 CY - Berlin AN - OPUS4-20096 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - Magnetic Response Field of Spherical Defects within Conductive Components T2 - 5th International Workshop Non-Destructive Testing in Progress CY - Prague, Czech Republic DA - 2009-10-12 PY - 2009 AN - OPUS4-20152 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kreutzbruck, Marc A1 - Allweins, K. A1 - Strackbein, C. A1 - Bernau, H. T1 - Inverse algorithm for electromagnetic wire inspection based on GMR-sensor arrays N2 - To meet the increasing fabrication quality standards and the high throughput requirements NDE techniques are reliant on efficient reconstruction tools and visualization tools. In this work we present an inverse algorithm for a modern electromagnetic non-destructive testing approach using a small GMR sensor array to inspect superconducting wires. Four sensitive GMR sensors are positioned around the wire. Small defects of 100 µm in size could be detected in a depth of 200 µm with a signal-to-noise ratio of better than 400. Surface defects could be detected with a SNR of up to 10,000. This remarkably SNR and the small extent of GMR sensors results in a spatial resolution which offers new visualisation techniques for defect localisation, defect characterization and future tomography-like mapping techniques. We developed several inverse algorithms based on either a Finite Element Method or an analytical approach leading to defect localization with an accuracy of a few 10 µm. KW - Nondestructive testing KW - Reconstruction KW - GMR-sensor array KW - Superconducting wires PY - 2009 DO - https://doi.org/10.3233/JAE-2009-1030 SN - 1383-5416 SN - 0925-2096 VL - 30 IS - 3-4 SP - 299 EP - 308 PB - IOS Press CY - Amsterdam, The Netherlands AN - OPUS4-20273 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Schlichting, Joachim A1 - Kervalishvili, Guram N. A1 - Maierhofer, Christiane A1 - Kreutzbruck, Marc ED - Mazal, Pavel T1 - Defect sizing by local excitation thermography T2 - 5th International workshop of NDT experts - NDT in progress 2009 CY - Prague, Czech Republic DA - 2009-10-12 KW - Thermography KW - Laser excitation KW - FEM modeling KW - Crack sizing PY - 2009 SN - 978-80-214-3968-9 SP - 261 EP - 270 AN - OPUS4-20333 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Völz, Uwe A1 - Mrasek, Heinz A1 - Matthies, Klaus A1 - Kreutzbruck, Marc ED - Mazal, Pavel T1 - Visualization of sound propagation with electrodynamic probes T2 - 5th International workshop of NDT experts - NDT in progress 2009 CY - Prague, Czech Republic DA - 2009-10-12 KW - Ultrasonic KW - Sound field KW - Visualization KW - Electrodynamic probe KW - Nondestructive testing (NDT) KW - Nickel alloy KW - Anisotropic weld KW - Narrow-gap weld PY - 2009 SN - 978-80-214-3968-9 SP - 321 EP - 328 AN - OPUS4-20334 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Gaal, Mate A1 - Döring, Joachim A1 - Brekow, Gerhard A1 - Kreutzbruck, Marc ED - Mazal, Pavel T1 - Detection of flaws with lamb waves and air-coupled ultrasound T2 - 5th International workshop of NDT experts - NDT in progress 2009 CY - Prague, Czech Republic DA - 2009-10-12 KW - Lamb waves KW - Air-coupled probes KW - Beam profile KW - Ultrasonic testing PY - 2009 SN - 978-80-214-3968-9 SP - 53 EP - 58 AN - OPUS4-20335 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 - GEN A1 - Schenk, Gottfried A1 - Brackrock, Daniel A1 - Brekow, Gerhard A1 - Kreutzbruck, Marc A1 - Deutsch, W.A.K. A1 - Joswig, M. A1 - Maxam, K. A1 - Schuster, V. ED - Mazal, Pavel T1 - Ultrasonic inspection system for automated round-bar-testing based on phased array technique T2 - 5th International workshop of NDT experts - NDT in progress 2009 CY - Prague, Czech Republic DA - 2009-10-12 KW - Ultrasonic testing KW - Phased array KW - Round bar testing PY - 2009 SN - 978-80-214-3968-9 SP - 253 EP - 259 AN - OPUS4-20338 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Prager, Jens A1 - Hoever, Carsten A1 - Brekow, Gerhard A1 - Kreutzbruck, Marc ED - Mazal, Pavel T1 - Flaw detection with guided waves using phased array technique T2 - 5th International workshop of NDT experts - NDT in progress 2009 CY - Prague, Czech Republic DA - 2009-10-12 KW - Ultrasonic testing KW - Guided waves KW - Plate-like structures PY - 2009 SN - 978-80-214-3968-9 SP - 203 EP - 212 AN - OPUS4-20339 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Heckel, Thomas A1 - Thomas, Hans-Martin A1 - Kreutzbruck, Marc A1 - Rühe, S. ED - Mazal, Pavel T1 - High speed non-destructive rail testing with advanced ultrasound and eddy-current testing techniques T2 - 5th International workshop of NDT experts - NDT in progress 2009 CY - Prague, Czech Republic DA - 2009-10-12 KW - Non-destructive testing (NDT) KW - Rail inspection KW - Ultrasound KW - Eddy current KW - Signal processing PY - 2009 SN - 978-80-214-3968-9 SP - 101 EP - 109 AN - OPUS4-20340 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Boehm, Rainer A1 - Brackrock, Daniel A1 - Kitze, Jessica A1 - Brekow, Gerhard A1 - Kreutzbruck, Marc ED - Mazal, Pavel T1 - Saft for crack surface analysis - Comparison of modeling and phased array measurements T2 - 5th International workshop of NDT experts - NDT in progress 2009 CY - Prague, Czech Republic DA - 2009-10-12 KW - Ultrasonic testing KW - SAFT KW - Phased array PY - 2009 SN - 978-80-214-3968-9 SP - 1 EP - 10 AN - OPUS4-20341 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Heckel, Thomas A1 - Thomas, Hans-Martin A1 - Kreutzbruck, Marc A1 - Rühe, S. T1 - High speed non-destructive rail testing with advanced ultrasound and eddy-current testing techniques N2 - Today the rails face increased exposure to heavy loads, higher speeds and a very dense overall traffic. A continued development of testing methods for the rail inspection trains became necessary to match the modern needs for a fast detection and detailed classification of defects. To guarantee the safe operation of rail traffic non-destructive inspection techniques with combined ultrasound and eddy current testing methods are used to detect damages on rails. One of the main actual challenges of automated rail testing is the high inspection speed which is very close to the physical limits. To overcome these limits digital signal processing algorithms have to be used which maintain resolution and detection quality independent of operation speed. This paper presents a recently developed state of the art rail inspection system which uses advanced ultrasonic and eddy current testing techniques. Testing results are shown in a newly developed so called Glassy-Rail-Diagram which is capable to present data with a fixed resolution independent of inspection speed. T2 - NDE 2009 CY - Tiruchirappalli, India DA - 2009-12-10 KW - Non-destructive testing (NDT) KW - Rail inspection KW - Ultrasound KW - Eddy current KW - Signal processing PY - 2009 SP - 261 EP - 265 AN - OPUS4-20883 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 - CONF A1 - Boehm, Rainer A1 - Brackrock, Daniel A1 - Kitze, Jessica A1 - Brekow, Gerhard A1 - Kreutzbruck, Marc T1 - The SAFT approach for advanced crack analysis T2 - NDE 2009 CY - Tiruchirappalli, India DA - 2009-12-10 PY - 2009 SP - 315 EP - 318 AN - OPUS4-20832 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Völz, Uwe A1 - Kreutzbruck, Marc A1 - Mrasek, Heinz A1 - Matthies, Klaus T1 - Visualization of sound propagation in solids using electrodynamic probes N2 - When dealing in ultrasonic testing with inhomogeneous material structure data interpretation can be rather difficult. This is especially the case when using anisotropic dissimilar welds made from austenitic steel or nickel based alloys, which are currently used for modern power plant concepts. In this work we present an electrodynamic technique to visualize sound waves with frequencies up to 3 MHz in steel components providing a simple use and a high signal-to-noise ratio. By detecting the grazing beam with an electrodynamic probe, we measured the particle displacement as a function of time with a spatial resolution in the order of 1 mm. Adapting the electrodynamic probe and its coil alignment allows for measuring the displacement components in all three dimensions. This comprises the detection of the horizontal and vertical particle displacement with respect to the surface and thus also the transformation from longitudinal waves into transversal waves and vice versa. We report on measurements of the sound field in a complex narrow-gap weld, joining a nickel alloy with a chrome steel with a substantial anisotropy of the weld structure. The test system enables us to visualize the wave propagation within the weld and indicates the reflection scenario and the energy losses due to both the anisotropic structure and material defects. T2 - IEEE International Ultrasonics Symposium 2009 CY - Rome, Italy DA - 2009-09-19 KW - Acoustic propagation KW - Anisotropic media KW - Nickel alloys KW - Nondestructive testing KW - Visualization PY - 2009 SN - 978-1-4244-4390-1 SN - 1948-5727 SP - 1495 EP - 1498 AN - OPUS4-21126 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Heckel, Thomas A1 - Kreutzbruck, Marc A1 - Montag, Hans-Joachim A1 - Fenger, S. T1 - The glassy rail: advanced ultrasonic rail inspection PY - 2010 SN - 0976-254X VL - 1 IS - 5 SP - 16 EP - 19 PB - Headliners Advertising Services Pvt. Ltd. CY - Kolkata, India AN - OPUS4-23269 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Brekow, Gerhard A1 - Kreutzbruck, Marc A1 - Boehm, Rainer A1 - Kitze, Jessica A1 - Eggers, H. A1 - Böwe, M. T1 - Using UT-SAFT for analysis of stress corrosion cracking N2 - Stress corrosion cracking is a transcrystalline or intercrystalline crack formation in materials which occurs under the influence of static tensile stress or residual stress and a specific aggressive medium such as chloride containing substances. This special sort of crack formation is involved in complex crack configurations, which may only insufficiently be captured by conventional ultrasonic probes with fixed angles of incidence. Only a number of different beam angles produce sufficient reflection to reconstruct the complete defect shape from measured ultrasonic data. The SAFT algorithm, which was recently successfully used in many industrial NDT-applications, is a promising tool for the reconstruction process. In addition, the combination of phased array technique and SAFT was developed in several projects by BAM, Berlin. Investigations using phased array equipment were performed to look into crack configurations in test blocks with different surface curvatures. UT-SAFT has been used for the analysis of spark-eroded notches simulating stress corrosion cracks at the thermo sleeve weld of a nozzle. For comparison, UT-SAFT has also been applied for the analysis of real reflectors at the same position in a nozzle used in a power plant, which was repaired later on. SAFT-scans received from reconstructed ultrasonic measurement data confirm the practical usefulness of the SAFTalgorithm developed by BAM. T2 - 8th International conference on NDE in relation to structural integrity for nuclear and pressurised components CY - Berlin, Germany DA - 2010-09-29 KW - Stress corrosion cracking KW - Real and simulated cracks KW - D-nozzle KW - Phased array technique KW - SAFT reconstruction PY - 2010 SN - 978-3-940283-30-6 IS - DGZfP-BB 125 (Th.2.B.1) SP - 1 EP - 10 CY - Berlin AN - OPUS4-23594 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - Cellular polypropylene ferroelectret film: Piezoelectric material for non-contact Ultrasonic transducers T2 - WCNDT 2008 CY - Shanghai, China DA - 2008-10-25 PY - 2008 AN - OPUS4-18171 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - High Resolution Eddy Current Testing of Superconducting Wires using GMR-Sensors T2 - WCNDT 2008 CY - Shanghai, China DA - 2008-10-25 PY - 2008 AN - OPUS4-18172 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - Quantitative Defect Sizing on Components with Different Wall Thickness using UT-SAFT T2 - WCNDT 2008 CY - Shanghai, China DA - 2008-10-25 PY - 2008 AN - OPUS4-18173 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc A1 - Allweins, K. A1 - Bernau, H. ED - Peter Scharff, T1 - Inverse Algorithm for Electromagnetic Wire Inspection based on GMR-Sensor Arrays T2 - 10th Workshop on optimization and inverse problems in electromagnetism (OIPE 2008) CY - Ilmenau, Germany DA - 2008-09-14 KW - Nondestructive Testing KW - Reconstruction KW - GMR-sensor array KW - Superconducting wires PY - 2008 IS - O6_1 SP - 137 EP - 138 CY - Ilmenau AN - OPUS4-18367 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc A1 - Allweins, K. A1 - Strackbein, C. A1 - Bernau, H. T1 - High Resolution Eddy Current Testing of Superconducting Wires using GMR-Sensors T2 - 17th World Conference on Non-Destructive Testing CY - Shanghai, China DA - 2008-10-25 KW - GMR-sensor KW - Eddy Current Testing KW - Reconstruction KW - Superconducting wires PY - 2008 IS - Paper 389 SP - 1 EP - 6 PB - International Committee for Non-Destructive Testing CY - Shanghai AN - OPUS4-18434 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Döring, Joachim A1 - Bovtun, V. A1 - Bartusch, Jürgen A1 - Beck, Uwe A1 - Kreutzbruck, Marc T1 - Cellular polypropylene ferroelectret film: piezoelectric material for non-contact ultrasonic transducers T2 - 17th World Conference on Non-Destructive Testing CY - Shanghai, China DA - 2008-10-25 KW - Air-coupled ultrasound KW - Ultrasonic transducers KW - Electromechanical properties KW - Piezoelectric materials KW - Impedance spectroscopy PY - 2008 IS - Paper 123 SP - 1 EP - 6 PB - International Committee for Non-Destructive Testing CY - Shanghai AN - OPUS4-18435 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Brekow, Gerhard A1 - Boehm, Rainer A1 - Brackrock, Daniel A1 - Kreutzbruck, Marc T1 - Quantitative Defect Sizing on Components with Different Wall Thickness using UT-SAFT T2 - 17th World Conference on Non-Destructive Testing CY - Shanghai, China DA - 2008-10-25 KW - UT-SAFT KW - Reconstruction PY - 2008 IS - Paper 122 SP - 1 EP - 6 PB - International Committee for Non-Destructive Testing CY - Shanghai AN - OPUS4-18436 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - Hochauflösende Wirbelstromprüfung - Ein Streifzug durch anspruchsvolle Prüfprobleme am Rande dreier Nobelpreise T2 - DGZfP - Arbeitskreis, 84. Sitzung CY - Zwickau, Germany DA - 2008-10-21 PY - 2008 AN - OPUS4-19258 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - Magnetische Mikrosysteme für die Hochauflösende Wirbelstromprüfung - Ein Streifzug durch anspruchsvolle Prüfsysteme am Rande dreier Nobelpreise T2 - DGZfP-Arbeitskreis Niedersachsen 355. Sitzung CY - Wolfsburg, Germany DA - 2009-04-23 PY - 2009 AN - OPUS4-19337 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Brekow, Gerhard A1 - Brackrock, Daniel A1 - Boehm, Rainer A1 - Kreutzbruck, Marc ED - Thompson, D. O. ED - Chimenti, D. E. T1 - Phased array-based SAFT for defect sizing on power plant components N2 - Quantitative NDE methods play a key role when it comes to inspect components, which requires high operational safety. UT-SAFT is one of the well-known reconstruction tools, which provides information about the defect size. In this work we studied the use of phased array technique in combination with the SAFT algorithm to inspect power plant components. As a first example we inspected a real-sized mock-up model representing a part of a reactor pressure vessel with a 180 mm-thick ferritic base material followed by a 6 mm-thick austenitic cladding layer. The phased array probe was coupled at the outer ferritic surface. We detected and sized fatigue cracks within the cladding with a depth ranging from 4 mm to 10 mm. Secondly, we investigated a mock-up model resembling a nozzle including a thermo sleeve inlet and a maximum wall thickness of about 37 mm. Artificially inserted notches with a depth of 3 mm could be detected and sized, where the thermo sleeve is welded at the inside of the nozzle. T2 - 35th Annual Review of Progress in Quantitative Nondestructive Evaluation CY - Chicago, IL, USA DA - 2008-07-20 KW - Ultrasonic testing KW - Phased arrays KW - SAFT KW - Power plant components PY - 2009 SN - 978-0-7354-0629-2 SN - 0743-0760 SN - 0094-243X N1 - Serientitel: AIP conference proceedings – Series title: AIP conference proceedings IS - 1096 SP - 872 EP - 879 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-19435 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Völz, Uwe A1 - Mrasek, Heinz A1 - Matthies, Klaus A1 - Wüstenberg, Hermann A1 - Kreutzbruck, Marc ED - Thompson, D. O. ED - Chimenti, D. E. T1 - Electrodynamic approach for visualization of sound propagation in solids N2 - The visualization of sound propagation in solids is vital for transducer adaptation and better understanding of complex test samples and their wave propagation modeling. In this work we present an electrodynamic technique detecting the grazing sound beam with a 10 mm-sized electrodynamic probe. The particle displacement along the sample’s surface was then measured as a function of time and position. Adapting the electrodynamic probe and its coil alignment allows for measuring the displacement components in all three dimensions. Thus horizontal and vertical particle displacement with respect to the surface can be detected. A SNR of up to 40 dB could be achieved within ferromagnetic and high conductive chrome steel when using a shear wave generated by an angle beam probe. When dealing with nonconductive materials such as PMMA we obtained a reduced SNR of 12 dB. We report on measurements of the sound field in complex weld joints. One example shows a narrow gap weld joining a nickel alloy with a chrome steel. The weld of the 80 mm-thick test block shows a distinct anisotropic texture. The system enables us to visualize the wave propagation within the weld and indicates the reflection and scattering scenario and the energy losses due to both the anisotropic structure and material defects. T2 - 35th Annual Review of Progress in Quantitative Nondestructive Evaluation CY - Chicago, IL, USA DA - 2008-07-20 KW - Ultrasonic KW - Sound field KW - Visualization KW - Electrodynamic probe KW - Nondestructive testing KW - Nickel alloy KW - Anisotropic weld KW - Narrow gap weld PY - 2009 SN - 978-0-7354-0629-2 SN - 0743-0760 SN - 0094-243X N1 - Serientitel: AIP conference proceedings – Series title: AIP conference proceedings IS - 1096 SP - 758 EP - 765 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-19436 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc A1 - Allweins, K. A1 - Strackbein, C. A1 - Bernau, H. ED - Thompson, D. O. ED - Chimenti, D. E. T1 - High resolution eddy-current wire testing based on a GMR sensor-array N2 - Increasing demands in materials quality and cost effectiveness have led to advanced standards in manufacturing technology. Especially when dealing with high quality standards in conjunction with high throughput quantitative NDE techniques are vital to provide reliable and fast quality control systems. In this work we illuminate a modern electromagnetic NDE approach using a small GMR sensor array for testing superconducting wires. Four GMR sensors are positioned around the wire. Each GMR sensor provides a field sensitivity of 200 pT/√Hz and a spatial resolution of about 100 µm. This enables us to detect under surface defects of 100 µm in size in a depth of 200 µm with a signal-to-noise ratio of better than 400. Surface defects could be detected with a SNR of up to 10,000. Besides this remarkably SNR the small extent of GMR sensors results in a spatial resolution which offers new visualisation techniques for defect localisation, defect characterization and tomography-like mapping techniques. We also report on inverse algorithms based on either a Finite Element Method or an analytical approach. These allow for accurate defect localization on the µm scale and an estimation of the defect size. T2 - 35th Annual Review of Progress in Quantitative Nondestructive Evaluation CY - Chicago, IL, USA DA - 2008-07-20 KW - GMR KW - Eddy current testing KW - Reconstruction KW - FEM PY - 2009 SN - 978-0-7354-0629-2 SN - 0743-0760 SN - 0094-243X N1 - Serientitel: AIP conference proceedings – Series title: AIP conference proceedings IS - 1096 SP - 1695 EP - 1702 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-19437 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Maierhofer, Christiane A1 - Röllig, Mathias A1 - Arndt, Ralf A1 - Kreutzbruck, Marc ED - Thompson, D. O. ED - Chimenti, D. E. T1 - Influence of surface properties on the detection and quantification of voids in concrete structures using active thermography N2 - Impulse thermography is an active method for quantitative investigations of the near surface region of various structures. It has recently been applied and optimized to applications in civil engineering. For quantitative analysis of data recorded on the building site, the problems are manifold. Here, the influence of the different surface properties on the detection and characterization of voids and honeycombing simulated by polystyrene cubes and cubes prepared of porous concrete are demonstrated. T2 - 35th Annual Review of Progress in Quantitative Nondestructive Evaluation CY - Chicago, IL, USA DA - 2008-07-20 KW - Active thermography KW - Pulse phase thermography KW - Surface properties KW - Emissivity KW - Concrete KW - Voids KW - Honeycombing PY - 2009 SN - 978-0-7354-0629-2 SN - 0743-0760 SN - 0094-243X N1 - Serientitel: AIP conference proceedings – Series title: AIP conference proceedings IS - 1096 SP - 1505 EP - 1511 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-19438 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Dohse, Elmar A1 - Kreutzbruck, Marc A1 - Schenk, Gottfried T1 - Vom "Logikgrab" zur Einchip-Lösung: Der Einsatz von FPGAs in digitalen Ultraschallgeräten T2 - DGZfP-Jahrestagung 2009 CY - Münster, Deutschland DA - 2009-05-18 KW - Ultraschall KW - Gerätetechnik PY - 2009 SN - 978-3-940283-16-0 IS - DGZfP-BB 115 ( Poster 36) SP - 1 EP - 2 AN - OPUS4-20515 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gaal, Mate A1 - Döring, Joachim A1 - Prager, Jens A1 - Brekow, Gerhard A1 - Kreutzbruck, Marc T1 - Fehlernachweis mit Plattenwellen und Luftultraschall T2 - DGZfP-Jahrestagung 2009 CY - Münster, Deutschland DA - 2009-05-18 KW - Plattenwellen KW - Luftultraschall KW - Ultraschallprüfung PY - 2009 SN - 978-3-940283-16-0 IS - DGZfP-BB 115 ( Di.1.A.2) SP - 1 EP - 7 AN - OPUS4-20516 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Boehm, Rainer A1 - Brackrock, Daniel A1 - Kitze, Jessica A1 - Brekow, Gerhard A1 - Kreutzbruck, Marc T1 - SAFT für die Rissflächenanalyse - Vergleich von Modellrechnungen und Gruppenstrahlermessungen T2 - DGZfP-Jahrestagung 2009 CY - Münster, Deutschland DA - 2009-05-18 KW - SAFT KW - Rissflächenanalyse PY - 2009 SN - 978-3-940283-16-0 IS - DGZfP-BB 115 (Mi.3.A.2) SP - 1 EP - 11 AN - OPUS4-20518 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hoever, Carsten A1 - Prager, Jens A1 - Brekow, Gerhard A1 - Kreutzbruck, Marc T1 - Fehlernachweis mit geführten Wellen unter Verwendung der Gruppenstrahlertechnik T2 - DGZfP-Jahrestagung 2009 CY - Münster, Deutschland DA - 2009-05-18 KW - Geführte Wellen KW - Gruppenstrahlertechnik PY - 2009 SN - 978-3-940283-16-0 IS - DGZfP-BB 115 (Poster 35) SP - 1 EP - 8 AN - OPUS4-20519 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kreutzbruck, Marc A1 - Thomas, Hans-Martin A1 - Sickert, Roland A1 - Casperson, Ralf A1 - Boehm, Rainer A1 - Allweins, K. A1 - Lemke, G. T1 - A numerical study of the inclusion problem in electromagnetic testing KW - FEM KW - Eddy Current Testing (ECT) KW - Eddy Current (EC) PY - 2009 SN - 0025-5300 VL - 51 IS - 11-12 SP - 819 EP - 827 PB - Hanser CY - München AN - OPUS4-20507 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Döring, Joachim A1 - Bartusch, Jürgen A1 - Kreutzbruck, Marc T1 - Spektroskopische Untersuchungen an Polypropylen-Schaumfolie mit Luftultraschall T2 - DGZfP-Jahrestagung 2009 CY - Münster, Deutschland DA - 2009-05-18 PY - 2009 SN - 978-3-940283-16-0 IS - DGZfP-BB 115 (Poster 39) SP - 1 EP - 2 AN - OPUS4-20509 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - Magnetic Response Field of Spherical Defects within Conductive Components T2 - NDE 2009, NDE in Power Industry CY - Tiruchirappalli, India DA - 2009-12-10 PY - 2009 AN - OPUS4-20565 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Schlichting, Joachim A1 - Kervalishvili, Guram N. A1 - Maierhofer, Christiane A1 - Kreutzbruck, Marc T1 - Defect sizing by local excitation thermography T2 - 15th International conference "Building services, mechanical and building industry days" CY - Debrecen, Hungary DA - 2009-10-15 KW - Thermography KW - Laser excitation KW - FEM Modeling KW - Crack sizing PY - 2009 SN - 978-963-473-315-7 SP - 67 EP - 76 AN - OPUS4-20655 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Prager, Jens A1 - Hoever, C. A1 - Kreutzbruck, Marc T1 - Untersuchungen zur Anregung geführter Wellen in Platten mittels Gruppenstrahlertechnik N2 - Geführte Wellen breiten sich in Platten und Hohlzylindern über weite Entfernungen aus. Aus dieser Eigenschaft ergibt sich ein hohes Anwendungspotential dieser Wellenart für die zerstörungsfreie Prüfung ausgedehnter Bauteile und Strukturen mittels Ultraschall. Nachteilig für die Anwendung geführter Wellen sind ihr dispersives Verhalten und die zunehmende Anzahl ausbreitungsfähiger Wellenmoden bei hohen Frequenzen. Ziel des Einsatzes der Gruppenstrahlertechnik ist es, eine ausgewählte Wellenmode selektiv anzuregen bzw. zu empfangen. Durch die Änderung des Schwenkwinkels im Gruppenstrahlerprüfkopf wird eine definierte Spurwellenlänge auf dem Interface zwischen Prüfkopf und Struktur festgelegt, die zur Anregung einer Welle mit entsprechender Phasengeschwindigkeit führt. Da der Schwenkwinkel elektronisch verändert werden kann, lässt sich auch die angeregte Wellenmode elektronisch auswählen, worin der große Vorteil des vorgestellten Verfahrens liegt. In den vorgestellten Untersuchungen wurde die Anwendbarkeit der Methode experimentell demonstriert. Der Anregemechanismus wurde theoretisch beleuchtet und die Wellenausbreitung im Prüfkopf mit verschiedenen analytischen Ansätzen modelliert. Mit diesen Modellen können Fragen der Richtwirkung und der Effizienz der Anregung detailliert untersucht werden. Die modellierten Wellenfelder wurden mit den experimentellen Ergebnissen verglichen und die Anwendbarkeit der theoretischen Ansätze beurteilt, wobei die Ergebnisse der theoretischen Untersuchungen im Experiment verifiziert werden konnten. T2 - DGZfP-Jahrestagung 2010 CY - Erfurt, Deutschland DA - 2010-05-10 PY - 2010 SN - 978-3-940283-26-9 IS - DGZfP-BB 122 (P41) SP - 1 EP - 5 CY - Berlin AN - OPUS4-21883 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schenk, Gottfried A1 - Brackrock, Daniel A1 - Boehm, Rainer A1 - Kreutzbruck, Marc A1 - Deutsch, W.A.K. A1 - Joswig, M. A1 - Maxam, K. A1 - Schuster, V. T1 - Untersuchungen zum Einfluss von Geometrie- und Temperaturabweichungen bei der Stangenprüfung mit Ultraschall-Gruppenstrahlertechnik N2 - Bei der automatisierten Prüfung von Stangen mit Ultraschall- Gruppenstrahlertechnik besteht grundsätzlich die Möglichkeit, Prüfkopfparameter wie Einschallwinkel, Fokustiefe und Schallbündelbreite programmgesteuert an sich verändernde Prüfbedingungen anzupassen. Zu diesen zählt die Temperatur des Koppelmediums (Wasser), die in einem Bereich von 10°C bis 50°C liegen kann, was zu unterschiedlichen Schallgeschwindigkeiten führt und den Einschallwinkel verändert. Mit der Folge, dass unter Umständen die geforderte 100%-Abdeckung des Prüfvolumens nicht mehr gewährleistet ist. Auch geometrische Abweichungen, wie sie durch die fertigungsbedingte Streuung des Prüflings gegeben sind, können Einfluss auf das Prüfergebnis nehmen. So führen Abweichungen vom idealen Geradheitszustand zu Fehlpositionierungen des Prüfkopfs, was wiederum Einfluss auf die Lage und Beschaffenheit des Schallbündels in der Stange hat. Ähnliches gilt für nicht vollkommen kreisförmig ausgebildete Stangendurchmesser, die unterschiedliche Schalleintrittsbedingungen bewirken und Abweichungen von den theoretisch ermittelten Werten zur Folge haben. Im Rahmen eines vom BMWi geförderten Forschungsvorhabens wurde der Einfluss dieser Parameter untersucht und ihre Auswirkungen für den Betrieb einer automatisierten Prüfanlage unter realen Betriebsbedingungen ermittelt. Dies betrifft vor allem den maximal möglichen Schallbündelversatz innerhalb des Arrays, der die Anzahl der erforderlichen Prüftakte bestimmt und damit die maximale Vorschubgeschwindigkeit des Prüflings. Des Weiteren werden Möglichkeiten zur programmgesteuerten Kompensation der untersuchten Temperatur- und Geometrieabweichungen durch eine flexible Anpassung der Gruppenstrahler- Prüfkopfparameter aufgezeigt. T2 - DGZfP-Jahrestagung 2010 CY - Erfurt, Deutschland DA - 2010-05-10 PY - 2010 SN - 978-3-940283-26-9 IS - DGZfP-BB 122 (Mi.4.A.1) SP - 1 EP - 8 CY - Berlin AN - OPUS4-21878 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kitze, Jessica A1 - Brackrock, Daniel A1 - Brekow, Gerhard A1 - Prager, Jens A1 - Gaal, Mate A1 - Kreutzbruck, Marc A1 - Szabo, D. A1 - Kuti, K. A1 - Paczolay, G. T1 - SAFT und TOFD - Ein Vergleich im Analyseverhalten von Reflektoren N2 - Mit der Gruppenstrahlertechnik der Bundesanstalt für Materialforschung und -prüfung sind umfangreiche Untersuchungen an einer plattierten Druckbehälter-Testwand durchgeführt worden. In der vorliegenden Testwand mit einer Wanddicke von 149 mm befinden sich künstliche Testreflektoren im Schweißnaht- und Plattierungsbereich, die mit Gruppenstrahler- Prüfköpfen mit unterschiedlichen Frequenzen, Einschallwinkeln und Einschallrichtungen nachgewiesen und in ihrem Anzeigenverhalten analysiert wurden. Zur Rekonstruktion der Reflektoranzeigen wurde ein SAFT - Algorithmus verwendet, der die Variation der Einschallwinkel berücksichtigt. Zum Vergleich sind die Reflektoren auch mit der TOFD - Technik analysiert worden. Ziel der Untersuchungen war der direkte Vergleich der Eignung der SAFT- und TOFDTechnik zur quantitativen Reflektorgrößenbestimmung. T2 - DGZfP-Jahrestagung 2010 CY - Erfurt, Deutschland DA - 2010-05-10 PY - 2010 SN - 978-3-940283-26-9 IS - DGZfP-BB 122 (Mi.2.A.3) SP - 1 EP - 11 CY - Berlin AN - OPUS4-21880 LA - deu 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 - CONF A1 - Schlichting, Joachim A1 - Kervalishvili, Guram N. A1 - Maierhofer, Christiane A1 - Kreutzbruck, Marc T1 - Geometrische Charakterisierung von Fehlstellen mittels lokal angeregter aktiver Thermografie N2 - In diesem Beitrag wird eine Methode zur Charakterisierung von offenen Oberflächenrissen mittels aktiver Thermografie präsentiert. Hierzu wird die Probe ortsfest lokal mit einem Laser erwärmt und die resultierende Oberflächentemperatur mittels Infrarotkamera aufgenommen. Bei einer ungestörten Probe ergibt sich ein rotationssymmetrisches Temperaturprofil. Betrachtet man hingegen einen Bereich mit einem Oberflächenriss, so kommt es durch die Störung des lateralen Wärmetransports zu einer unsymmetrischen Temperaturverteilung. Durch die quantitative Analyse diese Unsymmetrie lassen sich Aussagen über geometrische Parameter des Risses treffen. T2 - DGZfP-Jahrestagung 2010 CY - Erfurt, Deutschland DA - 2010-05-10 PY - 2010 SN - 978-3-940283-26-9 IS - DGZfP-BB 122 (Mi.1.C.2) SP - 1 EP - 8 CY - Berlin AN - OPUS4-21869 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schlichting, Joachim A1 - Kervalishvili, Guram N. A1 - Maierhofer, Christiane A1 - Kreutzbruck, Marc T1 - Geometrische Charakterisierung von Fehlstellen mittels lokal angeregter aktiver Thermografie / Characterizing geometrical parameters of voids with locally excited active thermography T2 - Sensoren und Messsysteme 2010 - 15. ITG/GMA-Fachtagung CY - Nürnberg, Deutschland DA - 2010-05-18 PY - 2010 SN - 978-3-8007-3260-9 IS - Paper 120 SP - 682 EP - 687 PB - VDE Verlag GmbH CY - Berlin, Offenbach AN - OPUS4-21855 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Schlichting, Joachim A1 - Maierhofer, Christiane A1 - Kreutzbruck, Marc T1 - Defect sizing by local excitation thermography N2 - In this article, we present a measurement procedure to gain information about depth and angle of open surface cracks. The method is based on a local excitation with, e.g., a laser. The resulting surface temperature is recorded with an infrared camera. Based on this data, crack-caused anisotropies in the lateral heat flow can be detected and exploited to characterise the cracks. The experimental set-up is based on a Nd:YAG laser. The beam is focused on the test sample by using an optical scanner to generate the required lateral heat flow. The time resolved temperature distribution is recorded with a high-speed infrared camera (InSb FPA, 3 to 5 µm) providing a frame rate of up to 500 Hz. Up to now, only qualitative information was gained from measurements of this type. Whereas the local transient behaviour of temperature distribution provides also quantitative information of the crack parameters. The general concept of the method presented herein has already been published [1], but the mentioned publication is focused on the crack depth only. In this paper, we can show that it is possible to simultaneously resolve the angle and depth and, in particular, the depth of non-perpendicular cracks. T2 - QIRT 10 - 10th International conference on Quantitative InfraRed Thermography CY - Québec, Canada DA - 2010-07-27 KW - FEM KW - Risse KW - Thermografie PY - 2010 UR - http://qirt.gel.ulaval.ca/archives/qirt2010/papers/QIRT%202010-121.pdf SN - 978-2-9809199-1-6 IS - QIRT 2010-121 SP - 773 EP - 780 AN - OPUS4-21957 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kienle, L. A1 - Duppel, V. A1 - Lembke, G. A1 - Mogwitz, B. A1 - Janek, J. A1 - Kreutzbruck, Marc A1 - Simon, A. T1 - Microstructure and magnetoresistance of heterogeneous gold-rich Ag3Au1.1Te2 N2 - Dispersions of very small non-magnetic metal particles or inclusions in a non-magnetic semiconductor matrix are well known to produce unusually large and linear magnetoresistance effects. So far these materials were limited to the binary silver-rich chalcogenides Ag2Se and Ag2Te. In this contribution Ag3AuTe2 was selected as a first candidate for a ternary matrix material, thus offering enhanced capabilities for the generation of heterogeneous microstructure and spatially varying composition on the nanoscale. In gold-rich Ag3Au1.1Te2 two kinds of inhomogeneities are present, namely Au deposits with a size on the micron scale and an inhomogeneous distribution of Au and Ag within the matrix. The matrix consists of micron-sized grains with the structure type of Ag3AuTe2 as studied by electron microscopy. Like the binary silver chalcogenide phases, the material also shows a large and linear magnetoresistance effect. The transversal magnetoresistance effect was measured between 20 K and 270 K in magnetic fields up to B = 5 T. The results are discussed on the basis of existing models for a large and linear positive MR effect. KW - Petzite KW - Magnetosensor KW - Electron microscopy KW - Nonstoichiometry KW - Magnetoresistance PY - 2010 DO - https://doi.org/10.1016/j.solidstatesciences.2010.07.029 SN - 1293-2558 SN - 1873-3085 VL - 12 IS - 10 SP - 1770 EP - 1778 PB - Elsevier CY - Amsterdam AN - OPUS4-22281 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - Hochauflösende MR-Sensor Arrays in der zerstörungsfreien Materialprüfung T2 - Ingenieurwissenschaftliches Kolloquium, Universität des Saarlandes CY - Saarbrücken, Germany DA - 2007-06-05 PY - 2007 AN - OPUS4-15019 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - Hochauflösende Wirbelstromprüfung - ein Streifzug durch anspruchsvolle Prüfprobleme T2 - DGZfP Arbeitskreis Magdeburg, PLR Prüftechnik Linke & Rühe CY - Magdeburg, Germany DA - 2007-06-29 PY - 2007 AN - OPUS4-15020 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - Moderne magnetoresistive Sensor Arrays für die ZFP - Vorteile und Grenzen T2 - DGZfP-Arbeitskreis Mannheim-Ludwigshafen CY - Mannheim, Germany DA - 2007-06-12 PY - 2007 AN - OPUS4-15021 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kreutzbruck, Marc A1 - Lembke, G. A1 - Korte, C. A1 - Franz, B. T1 - Galvanomagnetic transport properties of nitrogenated (La, Sr)MnO3-Delta and LaMnO3-Delta N2 - Epitaxial thin films of nitrogenated La0.65Sr0.30MnO3 were grown on MgO(100) substrates by pulsed laser deposition (PLD). The nitrogenation was achieved by a continuous nitrogen flow in the PLD chamber with pressures of up to 0.12 mbar. The chemical analysis of the samples regarding the exchange of oxygen by nitrogen was achieved by time of flight secondary ion mass spectrometry, sputtered neutral mass spectrometry (SNMS), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) and yielded a content of incorporated nitrogen ranging from 0.6% to 3.8%. Without nitrogenation the electrical resistivity of La0.65Sr0.30MnO3 exhibited a metal–insulator (MI) transition at about 180 K. The magnetoresistance (MR) effect (ΔR/R(0)) was about -50% at the transition temperature. Our nitrogen contents affected the MI transition so as to completely disappear and resulted in a resistivity increase of more than three orders of magnitude as well. By carefully reoxidizing the samples with subsequent heat treatments in air the MI transition reappeared at lower temperatures and we found a continuously enhanced MR ratio for decreasing temperatures. MR ratios of more than -99% were observed for a magnetic field of 10 T. The results are interpreted as a percolation phenomenon of ferromagnetic–metallic domains within an antiferromagnetic–semiconducting matrix. PY - 2007 DO - https://doi.org/10.1007/s00339-007-3982-0 SN - 0947-8396 VL - 88 IS - 1 SP - 201 EP - 208 PB - Springer CY - Berlin AN - OPUS4-15854 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - Magnetische Mikrosysteme in der zerstörungsfreien Materialprüfung T2 - Mikrosystemtechnik Kongress 2007 CY - Dresden, Germany DA - 2007-10-16 PY - 2007 AN - OPUS4-15682 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Brekow, Gerhard A1 - Boehm, Rainer A1 - Kreutzbruck, Marc T1 - Ultraschalluntersuchungen zur quantitativen Fehlergrößenbestimmung mit SAFT an dick- und dünnwandigen Anlagenkomponenten T2 - 33. MPA Seminar 2007 "Werkstoff- und Bauteilverhalten in der Energie- und Anlagentechnik" CY - Stuttgart, Deutschland DA - 2007-10-11 PY - 2007 SN - 1861-5414 IS - CD-ROM SP - 833 EP - 849 CY - Stuttgart AN - OPUS4-16441 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc A1 - Bernau, H. A1 - Allweins, K. A1 - Strackbein, C. T1 - Untersuchung zur 3D-Magnetotomographie in der Drahtprüfung mittels hochauflösendem GMR-Wirbelstromprüfsystem T2 - DGZfP-Jahrestagung 2007 CY - Fürth, Deutschland DA - 2007-05-14 KW - Magnetische Mikrosysteme KW - GMR-Sensor-Array PY - 2007 SN - 978-3-931381-98-1 SP - 1 EP - 9 (Poster 62) PB - DGZfP CY - Berlin AN - OPUS4-16449 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - Ultraschalluntersuchungen zur quantitativen Fehlergrößenbestimmung mit SAFT an dick- und dünnwändigen Anlagenkomponenten T2 - 33. MPA Seminar CY - Stuttgart, Germany DA - 2007-10-11 PY - 2007 AN - OPUS4-16422 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - Untersuchung zur 3D-Magnetographie in der Drahtprüfung mittels hochauflösendem GMR-Wirbelstromprüfsystem T2 - DGZfP-Jahrestagung 2007 CY - Fürth, Germany DA - 2007-05-14 PY - 2007 AN - OPUS4-16423 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schlichting, Joachim A1 - Maierhofer, Christiane A1 - Kreutzbruck, Marc T1 - Defect sizing by local excitation thermography N2 - In this article, we present a measurement procedure to gain information about depth and angle of surface braking cracks. The method is based on a local excitation with, e.g., a laser. The resulting surface temperature is recorded with an infrared camera. Based on this data, crack-caused anisotropies in the lateral heat flow can be detected and exploited to characterise the cracks. The experimental set-up is based on a Nd:YAG laser for heating and a high-speed infrared camera (InSb FPA, 3 to 5 µm) providing a frame rate of up to 500 Hz. Up to now, only qualitative information was gained from measurements of this type, whereas the local transient behaviour of temperature distribution provides also quantitative information of the crack parameters. Using FEM simulation we can show herein that it is possible to simultaneously resolve the angle and depth and, in particular, the depth of non-perpendicular cracks. KW - Surface braking cracks KW - Crack sizing KW - FEM KW - Laser thermography PY - 2011 DO - https://doi.org/10.3166/qirt.8.51-63 SN - 1768-6733 VL - 8 IS - 1 SP - 51 EP - 63 PB - Lavoisier CY - Cachan Cedex AN - OPUS4-24254 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schlichting, Joachim A1 - Ziegler, Mathias A1 - Dey, Anika A1 - Maierhofer, Christiane A1 - Kreutzbruck, Marc T1 - Efficient data evaluation for thermographic crack detection N2 - We present an all-purpose crack detection algorithm for flying spot thermography which is directly applicable to a thermogram sequence without the need of any additional information about the experimental setup. A single image containing distinct crack signatures is derived in two steps. Firstly, the spatial derivative is calculated for each frame of the sequence and, secondly, the resulting data set is sorted pixel wise along the time axis. The feasibility of the proposed procedure is proven by testing a piece of rail that comprises roll contact fatigue cracks and by comparing the results with magnetic particle testing. KW - Active thermography KW - Laser scanner KW - Railway KW - Roll contact fatigue KW - Open surface cracks PY - 2011 SN - 1768-6733 VL - 8 IS - 1 SP - 119 EP - 123 PB - Lavoisier CY - Cachan Cedex AN - OPUS4-24255 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schlichting, Joachim A1 - Ziegler, Mathias A1 - Pelkner, Matthias A1 - Maierhofer, Christiane A1 - Kreutzbruck, Marc T1 - Kameragestütztes Flying-Spot-Verfahren zur Risserkennung N2 - In dieser Arbeit wird ein kameragestütztes Verfahren zur Flying- Spot-Thermografie vorgestellt. Die Anregung wird über einen Diodenlaser mit einem optischen Scanner realisiert. Bei der Auswertung kommt ein effizienter und robuster Algorithmus zum Einsatz, der direkt auf die mit der Kamera aufgenommene Thermografiesequenz angewendet werden kann, ohne auf eine Synchronisation zwischen Kamera und Lasersystem angewiesen zu sein. Daher eignet sich diese Herangehensweise besonders zur Nachrüstung bestehender Thermografiesysteme. Die prinzipielle Eignung dieser Methode wird anhand einer Messung an einem Schienenstück mit Rollkontaktermüdungsrissen gezeigt. Als Referenzverfahren werden die Magnetpulverprüfung und eine auf GMR (Giant Magnetoresistance)- Sensoren basierende Streufeldmessung herangezogen. Mit dem thermografischen Verfahren konnten sämtliche enthaltenen Fehler erkannt werden. Dabei wurden Risse im mm-Abstand getrennt nachgewiesen, was etwa der geometrischen Auflösung der eingesetzten Kamera entspricht. T2 - Thermographie-Kolloquium 2011 CY - Stuttgart, Germany DA - 29.09.2011 KW - Flying-Spot Thermografie KW - Diodenlaser KW - Rissortung KW - Magnetpulverprüfung KW - GMR-Sensoren PY - 2011 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-246220 SN - 978-3-940283-36-8 IS - DGZfP-BB 130 (Vortrag 09) SP - 1 EP - 6 PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung e.V. (DGZfP) AN - OPUS4-24622 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - 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 DO - 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 - CONF A1 - Schlichting, Joachim A1 - Steinfurth, Henrik A1 - Maierhofer, Christiane A1 - Kreutzbruck, Marc T1 - Thermografische Prüfung von Punktschweißverbindungen N2 - Vor allem in der Automobilindustrie wird das Widerstandpunktschweißen im großen Unfang zur Verbindung von Blechen im Karosseriebau verwendet. Durch den anhaltenden Trend zum Leichtbau und den immer höheren Anforderungen an die passive Sicherheit kommt es hier zu einem verstärkten Einsatz innovativer hochfester Stähle. Obwohl es sich beim Punktschweißen um ein lange erprobtes Verfahren handelt, das sich anhand der Prozessparameter und regelmäßiger zerstörender Prüfung überwachen lässt, ist durch diese Entwicklung die Suche nach geeigneten zerstörungsfreien Prüfverfahren wieder aktuell. Wegen der hohen Produktionsgeschwindigkeiten in der automatisierten Fertigung muss sich das Prüfverfahren für eine hundertprozentige Prüfung vollautomatisch mit der typischen Taktrate von etwa einem Hertz durchführen lassen. In dieser Arbeit wird zuerst die prinzipielle Durchführbarkeit der thermografischen Prüfung von Punktschweißverbindungen an speziell präparierten Proben überprüft. Auf dieser Grundlage wird eine Serienuntersuchung an 75 Proben, die sich auf drei Gruppen von Schweißparametern aufteilen und neben optimal geschweißten Proben typische Fehlerbilder repräsentieren, eine Serienuntersuchung gezeigt. Hierzu wird eine Blitzlichtanregung in Transmissionsanordnung verwendet. Es kann gezeigt werden, dass sich mit einer geeigneten Datenaufbereitung die einzelnen Gruppen sicher trennen lassen. Durch eine statistische Bewertung der Ergebnisse kann unter Verwendung eines angepassten Gütekriteriums die Trennschärfe noch deutlich erhöht werden. T2 - DGZfP-Jahrestagung 2011 CY - Bremen, Germany DA - 30.05.2011 KW - Aktive Thermografie KW - Blitzlichtanregung KW - Punktschweißverbindung KW - Transmissionsmessung PY - 2011 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-249915 SN - 978-3-940283-33-7 IS - DGZfP-BB 127 (Di.1.C.3) SP - 1 EP - 7 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) AN - OPUS4-24991 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Richter, Regina A1 - Maierhofer, Christiane A1 - Kreutzbruck, Marc A1 - Schilling, M. T1 - Numerical method of active thermography for the reconstruction of back wall geometry N2 - The paper presents numerical methods to detect and classify defects and inhomogeneities by means of active thermography. The objective is to determine the wall thickness of structure elements with an inaccessible back wall, for example, of pipes or Containers. As test specimens we used approximately 2 cm thick PVC samples with spatial variations in the back wall geometry. Flash lamps provided the heating. To know the thickness of the wall, we used two inversion methods and compared the results achieved. One is an iterative echo defect shape method and already tested on Steel test specimens with good reconstruction results. The second one is the Levenberg-Marquardt method, applied here to thermographic data for non-destructive testing. Since data capturing using active thermography and the presented numerical methods can easily be automated, the combination of these two procedures is a promising approach providing a broad area of application. T2 - 6th Workshop 'NDT in progress' CY - Prague, Czech Republic DA - 10.10.2011 KW - Impulse-thermography KW - Inversion KW - Levenberg-Marquardt method KW - Echo defect shape KW - Defect shape reconstruction PY - 2011 SN - 978-80-214-4339-6 IS - Chapter 8 SP - 245 EP - 252 AN - OPUS4-25144 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Richter, Regina A1 - Kreutzbruck, Marc A1 - Maierhofer, Christiane T1 - Numerische Verfahren für die aktive Thermografie zur Untersuchung von Rückwandgeometrien N2 - In diesem Beitrag werden numerische Verfahren zur Erkennung und Charakterisierung von Fehlstellen, Schichtdicken, Wanddicken und Inhomogenitäten mittels aktiver Thermografie vorgestellt. Eine uantitative Beurteilung der nicht immer zugänglichen Rückwand eines Bauteils (Minderdicken) ist durch Inversion thermografischer Messdaten möglich. Diese quantitativen Informationen können durch iterative Methoden vom Gauß-Newton-Typ (Inversion) gewonnen werden. Als reale Prüfobjekte werden ca. 2 cm dicke PVC-Platten mit örtlich variierender Rückwandgeometrie untersucht. Die Erwärmung erfolgt mit Blitzlampen, welche die PVC-Platte kurzzeitig um mehrere K erwärmt. Ein wichtiger Teil der Inversion ist die Simulation des Experiments, welche mit Finite-Elemente-Methoden (FEM) in 2D realisiert wird. Da Inversion und active Thermografie automatisierbar sind, bietet die Kombination breite Anwendungsgebiete innerhalb der Industrie. T2 - DGZfP-Jahrestagung 2011 CY - Bremen, Deutschland DA - 30.05.2011 KW - Inversion KW - Aktive thermografie KW - Wanddicke KW - Rückwand KW - Minderdicken KW - Schichtdicken PY - 2011 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-252812 SN - 978-3-940283-33-7 IS - DGZfP-BB 127 (P45) SP - 1 EP - 6 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) AN - OPUS4-25281 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - Carbon nanomaterials as broadband airbone ultrasound transducer T2 - International Ultrasonics Symposium (IEEE 2011) CY - Orlando, FL, USA DA - 2011-10-18 PY - 2011 AN - OPUS4-25215 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Völz, Uwe A1 - Kreutzbruck, Marc A1 - Heckel, Thomas A1 - Mrasek, Heinz T1 - Verification of ultrasonic field modeling by visualization of wave propagation in solids N2 - When dealing in ultrasonic testing with inhomogeneous and anisotropic material structure such as diverse types of components made from austenitic or nickel based cast, which are currently used for modern power plant concepts, data interpretation is quite difficult. For better understanding of the complex interaction between the sound field and the component under test, the mathematical modeling of sound propagation in solids is a substantial task to increase the probability of detection of relevant defects. First we present a mathematical approach for modeling the three dimensional transient particle displacement as a function of time in each point in a half space excited by an impulsive point load at the surface. The transient ultrasonic field of a rectangular array element is calculated with this approach by a point source synthesis. Based on this solution we model the wave propagation of a phased array transducer by time delayed superposition of the wave field of the transducer elements. Next we use an electrodynamic technique to visualize the grazing sound field at the surface of a test block radiated by a phased array probe. By detecting the grazing beam at the sample’s surface with a small electrodynamic probe, we measured the particle displacement as a function of time. It allows for measuring the displacement in all three spatial directions. This comprises the detection of the horizontal and vertical particle displacement with respect to the surface and thus also the detection of longitudinal and shear waves is possible. The calculated and measured wave fields will be compared for different delay laws in isotropic and transversely isotropic media. The results support the theoretical activities to model the wave propagation and to find optimal testing parameters for different components and configurations. T2 - 8th International conference on NDE in relation to structural integrity for nuclear and pressurised components CY - Berlin, Germany DA - 2010-09-29 KW - Sound field KW - Wave propagation KW - Visualization KW - Modeling KW - Phased array PY - 2010 SN - 978-3-940283-30-6 IS - DGZfP-BB 125 (Th.4.A.2) SP - 1 EP - 7 CY - Berlin AN - OPUS4-25229 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kolkoori, Sanjeevareddy A1 - Rahman, Mehbub-Ur A1 - Prager, Jens A1 - Kreutzbruck, Marc T1 - Acoustic wave energy skewing and coefficients for the reflected and transmitted plane waves in general homogeneous transversely-isotropic austenitic materials N2 - In this contribution a simulation tool is developed to compute the energy skewing angles and energy coefficients for the reflected and refracted plane waves in following general cases: (1) reflection and refraction of plane elastic waves at an interface between isotropic and transversely isotropic solid, (2) reflection and refraction of plane elastic waves at an interface between transversely isotropic and isotropic solid, (3) reflection and refraction of plane elastic waves at an interface between two general transversely isotropic solid and (4) reflection of plane elastic waves from a stress free boundary of a transversely isotropic solid. Computational results for analytically evaluated acoustic wave energy skewing angles and energy reflection and transmission coefficients in acoustically anisotropic materials such as austenitic steel materials exhibiting columnar grain orientation are presented. The obtained results show that the acoustic energy skewing angles and coefficients in austenitic steel materials strongly depend upon the columnar grain orientation and are less influenced by the grain orientations which are parallel and perpendicular to the interface. T2 - 8th International conference on NDE in relation to structural integrity for nuclear and pressurised components CY - Berlin, Germany DA - 2010-09-29 KW - Anisotropy KW - Austenitic weld material KW - Energy skewing KW - Critical angle KW - Energy flux vector KW - Energy coefficients PY - 2010 SN - 978-3-940283-30-6 IS - DGZfP-BB 125 (Th.1.C.3) SP - 1 EP - 10 CY - Berlin AN - OPUS4-25232 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Reimund, Verena A1 - Pelkner, Matthias A1 - Neubauer, Andreas A1 - Thomas, Hans-Martin A1 - Kreutzbruck, Marc T1 - Automatische Detektion von Rissen in Stahlbauteilen unter Verwendung von GMR-Sensoren bei der magnetischen Streuflussprüfung N2 - GMR-Sensor Arrays ermöglichen eine örtlich hoch aufgelöste Messung magnetischer Streufeldamplituden an Stahlbauteilen, bei der abhängig von der Größe der zu prüfenden Oberfläche erhebliche Datenmengen erzeugt werden. Eine automatische Detektion von Rissen kann anschließend mittels digitaler Bildverarbeitung erreicht werden, welche hauptsächlich auf einer Kantenerkennung basiert. Diese wurde anhand einer Magnetometer-Messung getestet, die an einem zylindersymmetrischem Bauteil mit funkenerosiv eingebrachten Rissen geringer Tiefe durchgeführt wurde. Die erzielte Selektion der Defekte wird für eine angestrebte Rekonstruktion der Defektgeometrie benötigt. T2 - DGZfP-Jahrestagung 2011 CY - Bremen, Deutschland DA - 30.05.2011 KW - GMR-Sensor KW - Streuflussprüfung PY - 2011 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-253451 SN - 978-3-940283-33-7 IS - DGZfP-BB 127 (Mo.3.C.4) SP - 1 EP - 7 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) AN - OPUS4-25345 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Harrer, Andrea A1 - Prager, Jens A1 - Kreutzbruck, Marc A1 - Guderian, Matthias A1 - Meyer-Plath, Asmus T1 - Erzeugung von Luftultraschall mit mikro- und nanostrukturierten Kohlenstoffmaterialien unter Ausnutzung des thermoakustischen Prinzips N2 - In diesem Beitrag wird ein neuartiger Ansatz zur Erzeugung von Luftultraschall vorgestellt, der auf dem thermoakustischen Prinzip beruht. Mikro- und nanostrukturierte Kohlenstoffmaterialien werden dabei mit einem harmonischen Wechselstrom gespeist und erfahren durch ohmsche Verluste eine Temperaturänderung, die sich auf das umgebende Fluid überträgt. Daraus resultieren Druckmodulationen, und es wird eine ausbreitungsfähige Schallwelle erzeugt. Dabei tritt Frequenzverdopplung gegenüber der Anregungsfrequenz auf. Es konnte gezeigt werden, dass der entscheidende Parameter für die Effizienz der Methode, d.h. für ein möglichst großes Verhältnis von Schalldruck zu eingebrachter Leistung, die Wärmekapazität pro Flächeneinheit ist. Da dieser Quotient für Kohlenstoffmaterialien sehr klein sein kann, erlaubt das thermoakustische Prinzip hier die effiziente Erzeugung von Luftultraschall. Schalldruckmessungen an verschiedenen Materialproben wurden bis 100 kHz mit einem Mikrofon durchgeführt, oberhalb von 100 kHz wurde eine laservibrometrische Schnellemessung eingesetzt. In experimentellen Untersuchungen wurde die Schallerzeugung in Abhängigkeit der Materialeigenschaften analysiert und systematisiert. Die experimentellen Ergebnisse wurden mit numerischen und analytischen Berechnungsergebnissen verglichen. T2 - DAGA 2011 - 37. Jahrestagung für Akustik - Fortschritte der Akustik CY - Düsseldorf, Germany DA - 21.03.2011 KW - Thermoakustisches Prinzip KW - Luftultraschall KW - Kohelnstoffmaterialien PY - 2011 SN - 978-3-939296-02-7 SP - 339 EP - 340 AN - OPUS4-25328 LA - deu 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 T1 - Progress in Defect Sizing Nondestructive Testing Methoads T2 - International Symposium on Fatigue Design & Material Defects CY - Trondheim, Norway DA - 2011-05-23 PY - 2011 AN - OPUS4-25312 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - Progress in Acoustical Defect Sizing NDT Methods for the Inspection of Power Plant Components T2 - NDE 2011 CY - Chennai, India DA - 2011-12-08 PY - 2011 AN - OPUS4-25313 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - Recent NDE activities at BAM in Acoustical and Electromagnetic Methods T2 - Kolloquium IGCAR CY - Kalpakkam, India DA - 2011-12-13 PY - 2011 AN - OPUS4-25314 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - Modern techniques in Nondestructive Testing Methods T2 - Summerschool; Graduiertenkolleg TU Illmenau CY - Göttingen, Germany DA - 2011-09-28 PY - 2011 AN - OPUS4-25315 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - Potenziale technischer und biologischer Leichtbausysteme & Moderne bildgebende Verfahren in der zerstörungsfreien Prüfung zur Inspektion von Leichtbaukomponenten T2 - Kolloquium IZFP/Universität des Saarlandes CY - Saarbrücken, Germany DA - 2011-03-09 PY - 2011 AN - OPUS4-25316 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - Progress in Defect Sizing Nondestructive Testing Methods T2 - Kolloquium ALSTOM CY - Baden, Switzerland DA - 2011-08-18 PY - 2011 AN - OPUS4-25317 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - Bildgebende zerstörungsfreie Materialprüfung mittels akustischer und elektromagnetischer Sensor- und Aktorsysteme T2 - Kolloquium Fakultät für Maschinenwesen und Betriebswissenschaften, TU Wien CY - Vienna, Austria DA - 2011-06-01 PY - 2011 AN - OPUS4-25318 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - Insitu-Prüfung von ICE-Radsatzwellen; Skizze zu möglichen Prüfverfahren und ihrer physikalischen Machbarkeit T2 - Meeting Verband Deutscher Bahnindustrie CY - Berlin, Germany DA - 2011-09-21 PY - 2011 AN - OPUS4-25319 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - GMR Array Based Magnetic Flux Leakage Inspection T2 - NDE 2011 CY - Chennai, India DA - 2011-12-08 PY - 2011 AN - OPUS4-25320 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - Progress in Defect Sizing NDT Methods for the Inspection of Power Plant Components T2 - 37. MPA-Seminar 2011 CY - Stuttgart, Germany DA - 2011-10-06 PY - 2011 AN - OPUS4-25321 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - Thermoacoustic generation of airbone ultrasound using carbon materials at the micro- and nanoscale T2 - 15th International Symposium on Applied Electromagnetics and Mechanics CY - Naples, Italy DA - 2011-09-06 PY - 2011 AN - OPUS4-25301 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kienle, L. A1 - Duppel, V. A1 - Mogwitz, B. A1 - Janek, J. A1 - Kreutzbruck, Marc A1 - Leineweber, A. A1 - Simon, A. T1 - Synthesis - real structure - property: the showcase of silver-rich Ag2Se N2 - The structures and properties of silver selenide samples strongly depend on the method of preparation. Thin films prepared by pulsed laser deposition (PLD) contain lamellae of two low-temperature modifications of Ag2Se whose structures were analyzed in detail by electron microscopy techniques. Besides the stable and known Naumannite-type phase (LT1), a metastable phase was observed (LT2), and the phase transformation was examined in situ. Via cooling and annealing, LT2 becomes dominant in thin films, thus enabling solving the structure of LT2 by electron diffraction. These experiments and HRTEM point to an Acanthite-type (stable low-temperature modification of Ag2S) structure of LT2. Rapid-quenching procedures were applied for the first synthesis of LT2 as bulk sample. Depending on the conditions of melt spinning experiments, well-defined products were formed. In one series, we found a separation of LT1 and LT2 into distinct morphologies, i.e. microspheres and dendrites, respectively. The results on the magnetoresistance of the rapidly quenched materials support previous work. PY - 2011 DO - https://doi.org/10.1021/cg200167j SN - 1528-7483 VL - 11 IS - 6 SP - 2412 EP - 2421 PB - American Chemical Society CY - Washington, DC, USA AN - OPUS4-25388 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gaal, Mate A1 - Döring, Joachim A1 - Bartusch, Jürgen A1 - Bovtun, V. A1 - Brekow, Gerhard A1 - Kreutzbruck, Marc T1 - Charakterisierung der Wandler für Luftultraschallprüfung aus zellulärem Polypropylen-Ferroelektret N2 - In den letzten Jahren stieg die Anfrage für zerstörungsfreie Prüfung (ZIP) mit Luftultraschall deutlich. Die klassische ZfP mit Ultraschall nutzt Flüssigkeiten als Koppelmittel zwischen dem Wandler und dem Prüfkörper. Für die Prüfung von Gegenständen mit empfindlicher Oberfläche, die das Koppelmittel beschädigen oder verunreinigen kann, ist deswegen Luftultraschall besser geeignet. Eine mögliche Anwendung ist beispielsweise der Nachweis von Delaminationen in glas- und kohlefaserverstärkten Verbundwerkstoffen sowie Sandwichbauteilen, die in der Luftfahrt- und der Automobilindustrie eingesetzt werden. T2 - DAGA 2011 - 37. Jahrestagung für Akustik - Fortschritte der Akustik CY - Dusseldorf, Germany DA - 21.03.2011 KW - Luftultraschall KW - Wanderfolien KW - Zelluläres Polypropylen KW - Akustische Impedanz KW - Signal-Rausch-Anstand PY - 2011 SN - 978-3-939296-02-7 SP - 337 EP - 338 AN - OPUS4-26403 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gaal, Mate A1 - Döring, Joachim A1 - Bartusch, Jürgen A1 - Beck, Uwe A1 - Weise, Matthias A1 - Bovtun, Viktor Petrovic A1 - Brekow, Gerhard A1 - Kreutzbruck, Marc T1 - Parameter reproducibility of polypropylene ferroelectret transducers for air-coupled ultrasonic testing N2 - The extremely low acoustic impedance of polypropylene ferroelectret combined with its piezoelectric properties makes this material suitable for construction of aircoupled ultrasonic transducers for non-destructive testing. For the fabrication of transducers with a stable quality, the reproducibility of their key parameters is of interest. The reproducibility was evaluated by means of (i) impedance spectroscopy and (ii) pulse-echo measurements. (i) Impedance spectroscopy was applied to identify the resonance frequency, the coupling factor and the acoustic impedance of several nominally identical transducers. (ii) Pulse-echo measurements yielded the signal form of these transducers. The variation of the signal amplitude measured with pulseecho technique was about 10 dB. A part of this variation Comes from the deposition of transducer electrodes and another part from local variations of ferroelectret properties. The variation of the signal amplitude was caused by the observed variation of the coupling factor, which was also about 10 dB. The variation of the acoustic impedance was only about 1 dB, thus having no effect on the variation of the signal amplitude. These results indicate that the variability can be reduced by improving the control of electrode deposition and by optimizing the production technology affecting the reproducibility of material properties. T2 - 2011 IEEE International ultrasonics symposium (IUS) CY - Orlando, FL, USA DA - 18.10.2011 KW - Air-coupled ultrasonic transducers KW - Polypropylene ferroelectret KW - Reproducibility PY - 2011 IS - Abstract-ID 258 SP - 1 EP - 3 AN - OPUS4-26405 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - Flying Laser Spot Thermography for the Fast Detection of Surface Breaking Cracks T2 - 18th WCNDT 2012 (World Conference on Nondestructive Testing) CY - Durban, South Africa DA - 2012-04-16 PY - 2012 AN - OPUS4-26719 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - Progress in Acoustical Defect Sizing NDT Methods for the Inspection of Power-Plant Components T2 - 18th WCNDT 2012 (World Conference on Nondestructive Testing) CY - Durban, South Africa DA - 2012-04-16 PY - 2012 AN - OPUS4-26720 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - Adapted GMR Sensor Arrays used in Magnetic Flux Leakage Inspection T2 - 18th WCNDT 2012 (World Conference on Nondestructive Testing) CY - Durban, South Africa DA - 2012-04-16 PY - 2012 AN - OPUS4-26722 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kolkoori, Sanjeevareddy A1 - Shokouhi, Parisa A1 - Höhne, Christian A1 - Rahman, Mehbub-Ur A1 - Kreutzbruck, Marc A1 - Prager, Jens T1 - A comparative study of ray tracing and CIVA simulation for ultrasonic examination of anisotropic inhomogeneous austenitic welds N2 - Ultrasonic examination of anisotropic inhomogeneous austenitic welds is challenging, because of the columnar grain structure of the weld leads to beam skewing and splitting. Modeling tools play an important role in understanding the ultrasound field propagation and optimization of experimental parameters during the ultrasonic testing of austenitic welds as well as the interpretation of the test results. In this contribution, an efficient theoretical model based on the ray tracing concepts is developed to calculate the ultrasonic fields in inhomogeneous austenitic welds quantitatively. The developed model determines the ultrasound fields by taking into account the directivity of the ray source, the inhomogenity of the weld as well as ray transmission coefficients. Directivity of the ray source in columnar grained austenitic materials (including layback orientation) is obtained in three dimensions based on Lamb's reciprocity theorem. Ray energy reflection and transmission coefficients at an interface between two general columnar grained austenitic materials are calculated in three dimensions. The ray tracing model predictions on inhomogeneous austenitic weld material are compared against those from CIVA, a commercial non-destructive modeling and simulation tool. The ultrasonic modeling tools in CIVA are based on semi-analytical solutions. For beam propagation simulation, a so-called 'pencil method' is used, which involves modeling the probe as a set of individual source points, each radiating 'a bundle' of diverging rays into the medium and integrating those elementary contributions. Inhomogenity in the weld region is approximated by mapping the grain orientations on weld macrograph. Simulation results for ultrasonic field profiles for an austenitic weld are shown to be in good agreement with the corresponding experimental results. T2 - 39th Annual review of progress in quantitative nondestructive evaluation CY - Denver, Colorado, USA DA - 15.07.2012 KW - Crystal microstructure KW - Ray tracing KW - Ultrasonic materials testing KW - Ultrasonic propagation KW - Ultrasonic reflection KW - Ultrasonic transmission KW - Welds PY - 2013 SN - 978-0-7354-1129-6 DO - https://doi.org/10.1063/1.4789158 SN - 0094-243X SN - 1551-7616 N1 - Serientitel: AIP conference proceedings – Series title: AIP conference proceedings VL - 1511 SP - 1043 EP - 1050 PB - AIP Publishing AN - OPUS4-27736 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Richter, Regina A1 - Maierhofer, Christiane A1 - Kreutzbruck, Marc ED - Cardone, G. T1 - Numerical method of active thermography for the reconstruction of back wall geometry T2 - QIRT 11 - 11th International conference on Quantitative InfraRed Thermography CY - Prague, Czech Repubilc DA - 11.06.2012 KW - Rekonstruktion KW - Inverse Probleme KW - Defekte PY - 2012 SP - 1 EP - 9 AN - OPUS4-26446 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - A Resonance-Free Nanofilm Airborne Ultrasound Emitter N2 - In recent years the demand for airborne ultrasound techniques for non-destructive materials testing has increased remarkably. The applications for non-contact airborne ultrasound techniques are very broad and range from detection of flaws in composite laminates, solar cells and printed circuit boards to the applications in medicine and food industry. Conventional piezoelectric ultrasound transducers are mostly narrowbanded, show large resonance oscillations after a short excitation and therefore are generally not suitable for pulse-echo applications. In this contribution we present a novel thermoacoustic approach for the generation of broad band airborne ultrasound and investigate the applicability of resonance-free thermoacoustic emitters for very short high pressure airborne ultrasound pulses. We report on measurements of thermoacoustic emitters consisting of metal film below 50 nm thickness, generating sound pressure values of more than 140 dB in 60 mm distance and compare the results with piezoelectric airborne ultrasound transducers. Our experimental investigations show that such thermoacoustic devices can be used as a broad band emitters using pulse excitation. T2 - QNDE Conference 2012 CY - Denver, CO, USA DA - 2012-07-15 PY - 2012 AN - OPUS4-26756 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - Ultrasound and Thermographic Imaging for Weld Inspection T2 - NDE of Welds Short Course CY - Denver, CO, USA DA - 2012-07-14 PY - 2012 AN - OPUS4-26757 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Daschewski, Maxim A1 - Harrer, Andrea A1 - Prager, Jens A1 - Kreutzbruck, Marc A1 - Guderian, Matthias A1 - Meyer-Plath, Asmus ED - Linde, B. B. J. ED - Paczkowski, J. ED - Ponikwicki, N. T1 - Carbon nanomaterials as broadband airborne ultrasound transducer N2 - A method has been developed for the generation of airborne ultrasound using the thermoacoustic principle applied to carbon materials at the micro- and nanoscale. Such materials are shown to be capable to emitting the ultrasound. We tested the acoustic performance of electrospun polyacrylonitrile-derived carbon nanofibers tissues and determined the sound pressure for frequencies up to 350 kHz. The experimental results are compared to analytic calculations. T2 - International congress on ultrasonics CY - Gdansk, Poland DA - 2011-09-05 KW - Thermoacoustic KW - Airborne ultrasound transducer KW - Sound pressure PY - 2012 SN - 978-0-7354-1019-0 DO - https://doi.org/10.1063/1.3703262 SN - 0094-243X N1 - Serientitel: AIP conference proceedings – Series title: AIP conference proceedings IS - 1433 SP - 624 EP - 627 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-26788 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Döring, Joachim A1 - Bovtun, V. A1 - Gaal, Mate A1 - Bartusch, Jürgen A1 - Erhard, Anton A1 - Kreutzbruck, Marc A1 - Yakymenko, Y. T1 - Piezoelectric and electrostrictive effects in ferroelectret ultrasonic transducers N2 - Electromechanical response of polypropylene ferroelectret transducers under application of high-voltage pulses was measured by laser Doppler vibrometry and compared with results of ultrasonic through-air transmission between two ferroelectret transducers. The electromechanical response was completely explained by piezoelectric and electrostrictive effects. The electrostrictive effect dominates at high voltages and provides significant enlargement of the transducer constant, up to factor of 2.5. The induced strain of 1.7% was achieved at – 2000 V. The nonlinear ultrasonic transmission was shown to be well described by the piezoelectric and electrostrictive response of transmitter, except in the range of high negative exciting voltages where some limitation of the transmitted signal was observed. This limitation seems not to be a fundamental one and does not abolish the advantages of high-voltage excitation of polypropylene ferroelectret transducers. KW - Electromechanical effects KW - Ferroelectric devices KW - Piezoelectric transducers KW - Piezoelectricity KW - Ultrasonic transducers KW - Ultrasonic transmission KW - Cellular polypropylene KW - Ferroelectret KW - Electrostriction PY - 2012 DO - https://doi.org/10.1063/1.4759052 SN - 0021-8979 SN - 1089-7550 VL - 112 IS - 8 SP - 084505-1 - 084505-6 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-26806 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bovtun, Viktor Petrovic A1 - Döring, Joachim A1 - Bartusch, Jürgen A1 - Gaal, Mate A1 - Erhard, Anton A1 - Kreutzbruck, Marc A1 - Yakymenko, Y. T1 - Enhanced electromechanical response of ferroelectret ultrasonic transducers under high voltage excitation N2 - Polypropylene based ferroelectret films exhibit a strong electromechanical activity and provide a promising solution for the air coupled ultrasonic (ACUS) transducers. Ultrasonic transmission between two air coupled ferroelectret transducers in dependence on the amplitude and polarity of the high voltage exciting pulse revealed a strongly non-linear electromechanical response of the ferroelectret transmitter which provides an increase in the transmitter efficiency. The authors present a simple model describing both promotion and competition of the piezoelectric and electrostriction contributions, as well as increase in the transducer constant under high voltage excitation. Enlargement of the inverse transducer constant of the polypropylene ferroelectret film by a factor of 4 was demonstrated. The non-linear properties of the polypropylene ferroelectrets result in a strong increase in their ACUS figure of merit under the high voltage excitation, which exceeds the results of their technological optimisation. Consequently, enhancement of the ACUS system transmission by 12 dB and signal to noise ratio by 32 dB was achieved. KW - Air coupled ultrasonics KW - Non-contact transducers KW - Ferroelectrets KW - Piezoelectric effect KW - Electrostriction KW - Cellular polypropylene KW - Ultrasonic transducer PY - 2013 DO - https://doi.org/10.1179/1743676112Y.0000000021 SN - 1743-6753 SN - 1743-6761 VL - 112 IS - 2 SP - 97 EP - 102 PB - Maney CY - London AN - OPUS4-27880 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Richter, Regina A1 - Maierhofer, Christiane A1 - Kreutzbruck, Marc T1 - Numerical method of active thermography for the reconstruction of back wall geometry N2 - The paper presents a numerical method to detect and characterise defects and inhomogeneities by means of active thermography. The objective was to determine the wall thickness of structure elements with an inaccessible back wall, e.g., elements of pipes or containers. As test specimens we used PVC samples with the thickness of about 2 cm that had spatial variations in the back wall geometry. Flash lamps provided the heating. To measure the thickness of the wall, we employed the Levenberg–Marquardt method, which we applied here to experimental thermographic data for non-destructive testing. We started the inversion procedure by making a rough first estimation of the back wall geometry following the echo defect shape method, and then we calculated the thickness of the back wall. We found reasonable reconstruction results which differed from the real value significantly below 1 mm at the defect centre, whereas the error wais increased at the edge of the defect, depending on its shape and depth. KW - Pulse thermography KW - Wall thickness KW - Inverse problems KW - Reconstruction KW - Defects KW - Rekonstruktion KW - Inverse Probleme KW - Defekte PY - 2013 DO - https://doi.org/10.1016/j.ndteint.2012.10.010 SN - 0963-8695 VL - 54 SP - 189 EP - 197 PB - Butterworth-Heinemann CY - Oxford AN - OPUS4-28895 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - Matrix Phased Arrays for the Inspection of CFRP - Components T2 - qnde Conference, 10th International Conference on Barkhausen Noise & Micromagnetic Testing CY - Baltimore, MD, USA DA - 2013-07-21 PY - 2013 AN - OPUS4-29114 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - Moderne bildgebende Verfahren in der Zerstörungsfreien Prüfung zur Inspektion von Leichtbaukomponenten T2 - DGZFP Ehren-Kolloquium für Professor Dr. Heinrich Heidt CY - Berlin, Germany DA - 2013-01-15 PY - 2013 AN - OPUS4-29144 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - Evolution moderner Sensor- und Aktorsysteme für die Inspektion von Leichtbaukomponenten T2 - Kolloquium am IZFP-Saarbrücken CY - Saarbrücken, Germany DA - 2013-02-04 PY - 2013 AN - OPUS4-29145 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -