TY - CONF A1 - Kreutzbruck, Marc T1 - High resolution eddy-current wire testing based on a GMR sensor-array T2 - 35th Annual review of progress in quantitative nondestructive evaluation (QNDE) CY - Chicago, IL, USA DA - 2008-07-20 PY - 2008 AN - OPUS4-17766 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - Electrodynamic approach for visualization of sound propagation in solids T2 - 35th Annual Review of Progress in Quantitative Nondestructive Evaluation (QNDE) CY - Chicago, IL, USA DA - 2008-07-20 PY - 2008 AN - OPUS4-17767 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kreutzbruck, Marc A1 - Bernau, H. A1 - Allweins, K. T1 - Hochauflösende Wirbelstromprüfung mittels GMR-Sensorik am Beispiel supraleitender Drähte N2 - Aufgrund eines anhaltenden Trends der Miniaturisierung von Bauteilen sowie eines gesteigerten Qualitätsanspruches in Fertigung und Instandhaltung besteht ein wachsender Bedarf für hochauflösende zerstörungsfreie Prüfverfahren. Ein derzeit vielversprechender Lösungsansatz in der elektromagnetischen Prüfung wird durch die magnetischen Mikrosysteme eröffnet. Insbesondere die jüngst mit dem Physik-Nobelpreis ausgezeichnete GMR-Technologie bietet neben einer hohen Feldempfindlichkeit zugleich hervorragende Ortsauflösungen mit Schichtabmessungen bis in den unteren µm-Bereich. Hierdurch werden magnetische Feldverteilungen bei der Wirbelstromprüfung oder der Streuflussprüfung mit einem gegenüber Spulensystemen erhöhten Signal/Rausch-Verhältnis (SNR) und einer verbesserten Ortsauflösung gemessen. Im vorliegenden Beitrag wird das Potenzial der MR-Technologie anhand der Wirbelstromprüfung von Drähten verdeutlicht. Hierbei wird ein kreuzförmiges GMR-Sensor-Array um den zu untersuchenden Draht positioniert. Jeder einzelne GMR-Sensor misst dabei mit einer Feldempfindlichkeit von etwa 200pT/√Hz und einer Ortsauflösung von 100µm. Der Nachweis von im Durchmesser etwa 200µm großen Defekten in einer Tiefenlage von 200µm unterhalb der Drahtoberfläche gelingt mit einem SNR von über 400. Oberflächendefekte ähnlicher Größenordnung können mit einem SNR von nahezu 104 detektiert werden. Ein derart hohes SNR birgt in Kombination mit der hohen örtlichen Auflösung Potenzial für eine 3D-Fehlerlokalisierung. Unter Verwendung eines analytischen Ansatzes sowie auf FEM beruhende Dateninversionsalgorithmen können Defekte mit einer Abmessung von größer 200µm auf einige 10µm exakt lokalisiert werden. KW - GMR-Effekt KW - Sensor-Array KW - Wirbelstromprüfung KW - Drahtprüfung KW - Finite-Elemente-Methode KW - Rekonstruktion KW - GMR effect KW - Eddy current KW - Superconducting wire KW - Finite elements method KW - Reconstruction PY - 2008 DO - https://doi.org/10.1524/teme.2008.0879 SN - 0340-837X SN - 0178-2312 SN - 0171-8096 VL - 75 IS - 9 SP - 477 EP - 484 PB - Oldenbourg CY - München AN - OPUS4-18002 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - Influence of surface properties on the detection and quantification of voids in concrete structures T2 - 35th Annual Review of Progress in Quantitative Nondestructive Evaluation (QNDE) CY - Chicago, IL, USA DA - 2008-07-20 PY - 2008 AN - OPUS4-18003 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - Advanced Crack Shape Analysis using SAFT T2 - 36th Annual Review of Progress in Quantitative Nondestructive Evaluation (QNDE) CY - Kingston, RI, USA DA - 2009-07-26 PY - 2009 AN - OPUS4-19813 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - Ultrasonic Inspection system for automated Round-Bar-Testing based on Phased Array technique T2 - 36th Annual Review of Progress in Quantitative Nondestructive Evaluation (QNDE) CY - Kingston, RI, USA DA - 2009-07-26 PY - 2009 AN - OPUS4-19814 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - Magnetic Response Field of Spherical Defects with Conductive Components T2 - 36th Annual Review of Progress in Quantitative Nondestructive Evaluation (QNDE) CY - Kingston, RI, USA DA - 2009-07-26 PY - 2009 AN - OPUS4-19812 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - Flux leakage measurements for defect characterization using a high precision 3-axial GMR magnetic sensor T2 - Sensoren und Messsysteme 2010 CY - Nuremberg, Germany DA - 2010-05-18 PY - 2010 AN - OPUS4-21484 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 - Charakterisierung von Rissen mittels Laser angeregter aktiver Thermografie T2 - Thermographie-Kolloquium 2009 CY - Stuttgart, Germany DA - 2009-10-08 PY - 2009 IS - Vortrag 19 SP - 1 EP - 7 CY - Berlin AN - OPUS4-21571 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - Magnetic Response Field of Spherical Cefects within Conductive Components T2 - ENDE 2010 CY - Szczecin, Poland DA - 2010-06-13 PY - 2010 AN - OPUS4-21633 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - Ultraschallverfahren - Bewährte Lösungen und neue Technologien in Forschung und Produktion T2 - DGZfP-Jahrestagung 2010 CY - Erfurt, Germany DA - 2010-05-10 PY - 2010 AN - OPUS4-21754 LA - deu 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 - Boehm, Rainer A1 - Brackrock, Daniel A1 - Kitze, Jessica A1 - Brekow, Gerhard A1 - Kreutzbruck, Marc ED - Thompson, D.O. ED - Chimenti, D.E. T1 - Advanced crack shape analysis using SAFT N2 - The spatial resolution in ultrasonic testing as a wave phenomenon in nature is limited to a certain fraction of the wavelength, usually defined to be close to the Rayleigh criterion. In case of complicated reflector surfaces – such as stress corrosion cracking - this limitation prevents an exact visualization of the defect shape. There exist a few approaches to improve the spatial resolution, whose reconstruction quality all in common also depend on the achieved signal-to-noise ratio of the raw data. In this work we present a specific SAFT analysis, in which a high number of different angles of incidence produce a sufficiently high number of different reflections at the crack edges resulting in an improved SNR. In doing so, we reconstruct a coherent crack structure. First investigations were made at artificially simulated crack configurations with different contours and curvatures in flat and cylindrical test blocks. The measurements results – visualized by representative scans – show details of crack design and crack orientation. We also will present a comparison of the SAFT analysis between modelling and phased array measurements. T2 - 36th Annual Review of Progress in Quantitative Nondestructive Evaluation CY - Kingston, RI, USA DA - 2009-07-26 KW - Ultrasonic testing KW - SAFT KW - Phased array 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 - OPUS4-21816 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF 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 - Thompson, D.O. ED - Chimenti, D.E. T1 - Ultrasonic inspection system for automated round-bar-testing based on phased array technique N2 - Within a know-how transfer project funded by the government conventional ultrasonic technique was replaced by phased array technique for automated round-bar testing. Instead of applying a great number of conventional probes to achieve acceptable volume coverage we used curved linear arrays. The benefits of phased array technique such as programmable skew angles, beamforming and beam positions, led not only to a significant decrease in inspection time, but also the number of probes could be substantially reduced . Finally, the testing parameters for a large range of bar-diameters could be adapted by software control instead of time-consuming mechanical replacement. The probe-design was carried out by a proprietary modelling program. Both the theoretical calculations as well as the latter experimental verifications revealed significant advantages of curved arrays versus the planar types. A radial oriented probe offers perfect adaption to the cylindrical shape of the specimen allowing wide variations of the sound field. Thus beam direction, beam size and beam position could be optimized with respect to a minimum of inspection cycles, as inspections have to be executed in-line during the production. A number of laboratory tests were carried out on special test components. In order to achieve an optimal performance of the reference rod we implemented three different types of reference reflectors: (i) flat-bottom-holes with diameters of 0.8 mm and 1.2 mm, (ii) side-drilled-holes with a diameter of 0.7 mm for the detection of volumetric flaws, and (iii) notches with a depth of 0.2 mm and 0.5 mm for the detection of surfaceoriented defects. All laboratory tests were carried out with the COMPAS-XXL inspection system, a proprietary development of BAM. T2 - 36th Annual Review of Progress in Quantitative Nondestructive Evaluation CY - Kingston, RI, USA DA - 2009-07-26 KW - Ultrasonic testing KW - Phased array KW - Round bar testing PY - 2010 SN - 978-0-7354-0748-0 SN - 0743-0760 SN - 0094-243X N1 - Serientitel: AIP conference proceedings – Series title: AIP conference proceedings VL - 29 SP - 1 EP - 7 CY - Melville, NY AN - OPUS4-21817 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Döring, Joachim A1 - Bovtun, Viktor Petrovic A1 - Bartusch, Jürgen A1 - Erhard, Anton A1 - Kreutzbruck, Marc A1 - Yakymenko, Y. T1 - Nonlinear electromechanical response of the ferroelectret ultrasonic transducers N2 - The ultrasonic transmission between two air-coupled polypropylene (PP) ferroelectret (FE) transducers in dependence on the amplitude of the high-voltage exciting pulse revealed a strongly nonlinear electromechanical response of the FE transmitter. This phenomenon is described by a linear increase of the inverse electromechanical transducer constant t33(1) of the PP FE film with an increase of the exciting electrical pulse amplitude. Enlargement of t33(1) by a factor of 4 was achieved by application of 3500 V exciting pulses. The electrostriction contribution to t33(1) can be attributed to the electrostatic force between electrodes and the Maxwell stress effect. The nonlinear electromechanical properties of the PP FE result in a strong increase of its air-coupled ultrasonic (ACUS) figure of merit (FOM) under the high-voltage excitation, which exceeds results of the PP FE technological optimization. The FOM increase can be related to the increase of PP FE coupling factor and/or to the decrease of its acoustic impedance. A significant enhancement of the ACUS system transmission (12 dB) and signal-to-noise ratio (32 dB) was demonstrated by the increase of excitation voltage up to 3500 V. The nonlinear electromechanical properties of the PP FEs seem to be very important for their future applications. KW - Airborne ultrasonics KW - Electret film KW - Transducer KW - Nonlinearity PY - 2010 DO - https://doi.org/10.1007/s00339-010-5752-7 SN - 0947-8396 VL - 100 IS - 2 SP - 479 EP - 485 PB - Springer CY - Berlin AN - OPUS4-21809 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Völz, Uwe A1 - Mrasek, Heinz A1 - Matthies, Klaus A1 - Kreutzbruck, Marc T1 - Visualization of sound propagation with 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. For better understanding of the complex interaction between the sound field and the component under test, the visualization of sound propagation in solids is a substantial task to increase the probability of detection of relevant defects. However, there exist only a small number of appropriate techniques published today, such as scanning laser interferometer, piezoelectric and optical approaches in case of transparent solids. In this work we present an electrodynamic technique providing a simple use and a high signal to noise ratio. By detecting the grazing beam with an electrodynamic probe with a size smaller than 10 mm, 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 is possible. A SNR of higher than 36 dB could be achieved within ferromagnetic and high conductive chrome steel when using a transversal wave generated by an angled beam transducer. We report on measurements of the sound field in complex weld joints. One example shows a 10 mm thick narrowgap weld joining a nickel alloy with a chrome steel yielding 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 - ECNDT 2010 - 10th European conference on non-destructive testing CY - Moscow, Russia DA - 2010-06-07 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 - 2010 SN - 978-1-617-82791-4 SP - 1 EP - 8 AN - OPUS4-22974 LA - eng 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 - TY - GEN 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 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 - C5/115 SP - 650 EP - 657 PB - VDE-Verl. CY - Berlin; Offenbach AN - OPUS4-22971 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Prager, Jens A1 - Hoever, Carsten A1 - Brekow, Gerhard A1 - Kreutzbruck, Marc T1 - Flaw detection with guided waves using phased array technique N2 - Guided waves travel in plates and hollow cylinders over large distances and propagate with multiple mode shapes. Therefore the waves can be used viably for integrity tests of large scale structures. The number of propagating modes increases with frequency. Due to their dispersive character the different modes are manageable only in a limited frequency range. Depending on the wave length and on the angle of impingement of the wave front to the coupling surface between transducer and structure, a trace wavelength is predefined and a selective excitation of single modes becomes feasible. By using phased array technique the excited wave mode can be selected by controlling the input signal of the transducer. Different modes are excitable with a sin-gle mechanical set-up. In a first step of the investigation, a calculation model is developed modelling the wave propagation and the selective excitation of guided wave modes depending on the control parameters. Dedicated experiments show the applicability of the method presented. The flaw detection of different sized cracks and of material thickness reductions is examined depending on the excitation wave mode. T2 - ECNDT 2010 - 10th European conference on non-destructive testing CY - Moscow, Russia DA - 2010-06-07 KW - Ultrasonic testing KW - Guided waves KW - Plate-like structures PY - 2010 SN - 978-1-617-82791-4 SP - 1 EP - 10 AN - OPUS4-22972 LA - eng 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 - Heat transfer modeling of local thermal excitation for surface crack detection and characterization N2 - In the presented paper the use of local excitation (laser beam) for crack detection and characterization is simulated. As we could see, using the temperature differences between two reference points was large enough to detect and characterize the crack, even for such small value of laser power as 2 W. The influence of radiation and convection on the temperature difference was negligible (about 0.1%). The influence of heat conduction, in case of crack with air, was very small (about 3%). The main mechanism which influences the temperature differences between the reference points is the heat conduction in steel. From the presented results one can see that temperature differences are increasing with an increase of the crack depth or the crack length. Better resolution and characterization of the crack depths and lengths should be achieved with increased duration of heating time or the laser power. We could also see that the best position for the laser spot to characterize the crack is the closest one. Also, comparison of 2D and 3D simulation results for circular heat source used as local excitation mechanism had showed that only full 3D modelling will allow accomplishing a quantitative level of comparison between experimental and simulation results. T2 - ECNDT 2010 - 10th European conference on non-destructive testing CY - Moscow, Russia DA - 2010-06-07 KW - Thermography KW - Heat transfer modeling KW - Surface crack PY - 2010 SN - 978-1-617-82791-4 SP - 1 EP - 10 AN - OPUS4-22973 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc A1 - Brekow, Gerhard A1 - Böhm, R. A1 - Montag, Hans-Joachim A1 - Allweins, K. A1 - Strackbein, C. A1 - Bernau, H. T1 - Visualization of material defects - modern approaches in acoustical and electrical NDE-methods 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. Fast NDE-systems using a high degree of automatisation can be used for both determining the degree of integrity of the components under test and indicating a change of production parameters as well. However, independently of the applied NDE method and the underlying physical principle a reliable visualisation of hidden defects within the component under test is based on a sufficient high signal to noise ratio (SNR) and a high spatial resolution. In this talk we illuminate two standard NDT methods such as Ultrasonic Testing and Eddy Current Testing and show their physical principles also discussing the interaction between sound waves or induced eddy currents with different kinds of material defects. This introduction substantiates the attainable SNR and spatial resolution of both methods with respect to defect sizing and defect classification. As a first future prospect we report on the SAFT-algorithm to improve SNR and spatial resolution paving the way for a flaw sizing approach in ultrasonic inspection. As a second modern NDE approach we represent the use of small magnetoresistance sensor arrays for EC testing of Al-laser welds or for testing superconducting wires. The high sensitivity and small extent of GMR sensors results in a remarkably SNR and spatial resolution offering new visualisation techniques for defect localisation, defect characterization and tomography-like mapping techniques. T2 - ICAMT 2008 - International Conference on Advances in Manufacturing Technology for Young Engineers CY - Madras, Chennai, India DA - 2008-02-06 PY - 2008 IS - CD-ROM (A.4 / I-1) SP - 1 PB - Indian National Academy of Engineering (INAE) CY - Madras, Chennai, India AN - OPUS4-17622 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -