TY - JOUR A1 - Haller, T. A1 - Völker, Christoph A1 - Hartmann, T. T1 - Machine learning based multi-sensor fusion for the nondestructive testing of corrosion in concrete N2 - Half-cell potential mapping (HP) is the most popular non-destructive testing method (NDT) for locating corrosion damage in concrete. It is generally accepted that HP is susceptible to environmental factors caused by salt-related deterioration, such as different moisture and chloride gradients. Additional NDT methods are able to identify distinctive areas but are not yet used to estimate more accurate test results. We present a Supervised Machine Learning (SML) based approach to data fusion of seven different signal features to obtain higher quality information. SMLs are methods that explore (or learn) relationships between different (sensor) data from predefined data labels. To obtain a representative, labelled data set we conducted a comprehensive experiment simulating the deterioration cycle of a chloride exposed device in the laboratory. Our data set consists of 18 measurement campaigns, each containing HP, Ground Penetrating- Radar, Microwave Moisture and Wenner resistivity data. We compare the performance of different ML approaches. Many outperform the best single method, HP. We describe the intrinsic challenges posed by a data-driven approach in NDT and show how future work can help overcome them. T2 - SMAR2019 - 5th International Conference on Smart Monitoring, Assessment and Rehabilitation of Civil Structures CY - Potsdam, Germany DA - 27.08.2019 KW - Machine Learning KW - NDT KW - Half-Cell Potential Mapping KW - Corrosion KW - Reinforced Concrete KW - Data Fusion PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-498563 UR - http://www.ndt.net/?id=24890 VL - 25 IS - 1 SP - 24890-1 EP - 24890-8 PB - NDT.net CY - Kirchwald AN - OPUS4-49856 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Puthiyaveettil, N. A1 - Kidangan, R. A1 - Unnikrishnakurup, Sreedhar A1 - Krishnamurthy, C. V. A1 - Ziegler, Mathias A1 - Myrach, Philipp A1 - Balasubramaniam, K. T1 - Numerical study of laser line thermography for crack detection at high temperature N2 - The detection of cracks before the failure is highly significant when it comes to safety-relevant structures. Crack detection in metallic samples at high surface temperature is one of the challenging situation in manufacturing industries. Laser thermography has already proved its detection capability of surface cracks in metallic samples at room temperature. In this work a continuous wave (CW) laser use to generate a laser, which is using to scan the metal surface with notch. The corresponding heat distribution on the surface monitored using infrared thermal (IR) camera. A simplified 3D model for laser thermography is developed and validated with experimental results. A dedicated image processing algorithm developed to improve the detectability of the cracks. To understand the dependency of surface temperature, laser power, laser scanning speed etc. in defect detection, we carried out parametric studies with our validated model. Here we Report the capability of laser thermography in crack detection at elevated temperature. T2 - 14th Quantitative InfraRed Thermography Conference CY - Berlin, Germany DA - 25.06.2018 KW - Thermal contrast KW - Laser Thermography KW - FEM KW - Surface cracks KW - NDT PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-499113 DO - https://doi.org/10.21611/qirt.2018.076 SN - 2371-4085 VL - 2018 SP - 685 EP - 686 AN - OPUS4-49911 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lecompagnon, Julien A1 - Hirsch, Philipp Daniel A1 - Rupprecht, C. A1 - Ziegler, Mathias T1 - Hochaufgelöste thermografische Detektion eingeschlossener Defekte mit Hilfe von 2Dstrukturierten Beleuchtungsmustern N2 - Für die aktive Thermografie als zerstörungsfreie Prüfmethode galt lange Zeit die Faustformel, dass die Auflösung interner Defekte/Inhomogenitäten auf ein Verhältnis von Defekttiefe/Defektgröße ≤ 1 beschränkt ist. Die Ursache hierfür liegt in der diffusiven Natur der Wärmeleitung in Festkörpern. Sogenannte Super-Resolution-Ansätze erlauben seit Kurzem die Überwindung dieser physikalischen Grenze um ein Vielfaches. Damit ergibt sich die attraktive Möglichkeit die Thermografie von einem rein oberflächensensitiven Prüfverfahren hin zu einem Verfahren mit verbesserter Tiefenreichweite zu entwickeln. Wie weit diese Entwicklung getrieben werden kann, ist Gegenstand aktueller Forschung. Wir konnten bereits zeigen, dass diese klassische Grenze für 1D- und 2D Defektgeometrien mit Hilfe des Abscannens des Prüfkörpers mittels einzelner Laserspots und der anschließenden Anwendung von photothermischer Super-Resolution-Rekonstruktion überwunden werden kann. Bei dieser Methode wird eine Kombination aus sequenzieller räumlich strukturierter Beleuchtung und numerischen Optimierungsmethoden eingesetzt. Dies geschieht allerdings auf Kosten der experimentellen Komplexität, die zu einer langen Messdauer, großen Datensätzen und langwieriger numerischer Auswertung führt. In dieser Arbeit berichten wir über einen neuen experimentellen Ansatz, bei dem räumlich strukturierte 2D-Beleuchtungsmuster in Verbindung mit Compressed-Sensing und Computational-Imaging-Methoden verwendet werden, um die experimentelle Komplexität deutlich zu verringern und die Methode für die Untersuchung größerer Prüfflächen nutzbar zu machen. Der experimentelle Ansatz basiert dabei auf der wiederholten (blinden) photothermischen Anregung mit räumlich strukturierten 2D-Mustern unter Verwendung moderner Projektortechnik und eines Hochleistungslasers. In der anschließenden numerischen Rekonstruktion werden mehrere Messungen unter Ausnutzung der Joint-Sparsity der Defekte innerhalb des Prüfkörpers mittels nichtlinearer konvexer Optimierungsmethoden kombiniert. Als Ergebnis kann eine 2D-sparse Defekt-/Inhomogenitätskarte erstellt werden. T2 - DGZfP-Jahrestagung 2022 CY - Kassel, Germany DA - 23.05.2022 KW - Thermografie KW - Super resolution KW - NDT KW - ZfP KW - Eingeschlossene Defekte KW - Projektor PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-548945 SN - 978-3-947971-25-1 VL - 177 SP - 1 EP - 16 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung AN - OPUS4-54894 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Klewe, Tim A1 - Völker, Tobias A1 - Götz, J. A1 - Landmann, M. A1 - Wilsch, Gerd A1 - Kruschwitz, Sabine T1 - Sorting of construction and demolition waste by combining LIBS with NIR spectroscopy N2 - In a joint project of partners from industry and research, the automated recycling of construction and demolition waste (CDW) is investigated and tested by combing laser-induced breakdown spectroscopy (LIBS) and near-infrared (NIR) spectroscopy. Joint processing of information (data fusion) is expected to significantly improve the sorting quality of various materials like concrete, main masonry building materials, organic components, etc., and may enable the detection and separation of impurities such as SO3-cotaining building materials (gypsum, aerated concrete, etc.). The project focuses primarily on the Berlin site to analyze the entire value chain, minimize economic/technological barriers and obstacles at the cluster level, and sustainably increase recovery and recycling rates. First measurements with LIBS and NIR spectroscopy show promising results in distinguishing various material types and indicate the potential for a successful combination. In addition, X-ray fluorescence (XRF) spectroscopy is being performed to obtain more information about the quantitative elemental composition of the different building materials. Future work will apply the developed sorting methodology in a fully automated measurement setup with CDW on a conveyor belt. T2 - NDT-CE 2022 CY - Zurich, Switzerland DA - 16.08.2022 KW - LIBS KW - NDT KW - Circular economy KW - Recycling KW - Material classification PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-555531 UR - http://www.ndt.net/?id=27220 VL - 2022/09 SP - 1 EP - 9 PB - NDT.net CY - Bad Breisig AN - OPUS4-55553 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lecompagnon, Julien A1 - Hirsch, Philipp Daniel A1 - Rupprecht, C. A1 - Ziegler, Mathias ED - Maldague, X. T1 - Detection of internal defects applying photothermal super resolution reconstruction utilizing two-dimensional high-power random pixel patterns N2 - In this work, we report on our progress for investigating a new experimental approach for thermographic detection of internal defects by performing 2D photothermal super resolution reconstruction. We use modern high-power laser projector technology to repeatedly excite the sample surface photothermally with varying spatially structured 2D pixel patterns. In the subsequent (blind) numerical reconstruction, multiple measurements are combined by exploiting the joint-sparse nature of the defects within the specimen using nonlinear convex optimization methods. As a result, a 2D-sparse defect/inhomogeneity map can be obtained. Using such spatially structured heating combined with compressed sensing and computational imaging methods allows to significantly reduce the experimental complexity and to study larger test surfaces as compared to the one-dimensional approach reported earlier. T2 - Quantitative Infrared Thermography 2022 CY - Paris, France DA - 04.07.2022 KW - Thermography KW - Super resolution KW - NDT KW - inspection KW - Internal defects KW - DMD KW - DLP PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-577795 DO - https://doi.org/10.21611/qirt.2022.1005 SN - 2371-4085 SP - 1 EP - 7 PB - QIRT Council AN - OPUS4-57779 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Klewe, Tim A1 - Völker, Tobias A1 - Landmann, Mirko A1 - Kruschwitz, Sabine T1 - LIBS‐ConSort: Development of a sensor‐based sorting method for construction and demolition waste N2 - AbstractA joint project of partners from industry and research institutions approaches the challenge of construction and demolition waste (CDW) sorting by investigating and testing the combination of laser‐induced breakdown spectroscopy (LIBS) with near‐infrared (NIR) spectroscopy and visual imaging. Joint processing of information (data fusion) is expected to significantly improve the sorting quality of various materials like concrete, main masonry building materials, organic components, etc., and may enable the detection and separation of impurities such as SO3‐cotaining building materials (gypsum, aerated concrete, etc.)Focusing on Berlin as an example, the entire value chain will be analyzed to minimize economic / technological barriers and obstacles at the cluster level and to sustainably increase recovery and recycling rates.The objective of this paper is to present current progress and results of the test stand development combining LIBS with NIR spectroscopy and visual imaging. In the future, this laboratory prototype will serve as a fully automated measurement setup to allow real‐time classification of CDW on a conveyor belt. T2 - 21st Ibausil - International Conference on Building Materials CY - Weimar, Germany DA - 13.09.2023 KW - NDT KW - Material cassification KW - Recycling KW - LIBS KW - Data fusion KW - Construction and demolition waste KW - Circular economy PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-590734 DO - https://doi.org/10.1002/cepa.2866 SN - 2509-7075 VL - 6 IS - 6 SP - 973 EP - 976 PB - Ernst & Sohn GmbH AN - OPUS4-59073 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zscherpel, Uwe A1 - Ewert, Uwe T1 - Electronic reference images for flaw indications in welds and castings N2 - Since decades the evaluation of flaw indications on radiographs from welds or castings are based on well accepted reference film catalogues from organizations like IIW (weldments), ASTM (castings) or DGZfP (D5 recommendation on heavy steel castings). Today, the transformation of classical film radiography to the digital world is in full progress. Some ASTM standards do not permit the evaluation of digital radiographs in reference to film catalogues. Therefore, these reference film catalogues have to be converted into the digital age too. BAM is supporting this transition by high definition film scanning. The result is a corresponding reference image catalogue. The different standard organizations selected different ways to distribute the digital data. ASTM used high definition film scanning at 10 μm pixel size and distribution of a huge amount of high-res data via DVD. The user sub-samples these high-res data during catalogue import to the resolution of his system. The comparison is done by synchronized image viewing on the computer work station. IIW recently decided to distribute their ISO 5817 reference images installed on tablets, which are used for image viewing too. The tablet image has to be compared with the digital image on the system monitor. DGZfP transformed their D5 reference radiographs into a PDF for monitor viewing. This is the simplest and cheapest solution, but still allows the full usage of the catalogue in the digital era. The status of ongoing work in progress will be discussed. T2 - WCNDT 2016 CY - Munich, Germany DA - 13.06.2016 KW - Castings KW - NDT KW - RT KW - Radiography KW - Discontinuities KW - Catalogues KW - Welds PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-377306 UR - http://ndt.net/?id=19310 SN - 1435-4934 VL - 21 IS - 7 SP - 1 EP - 8 PB - NDT.net CY - Kirchwald AN - OPUS4-37730 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bertovic, Marija T1 - Assessing and Treating Risks in Mechanised NDT: A Human Factors Study N2 - Reliability of NDT is affected by human factors, which have thus far received the least amount of attention in the reliability assessments. With increased use of automation, in terms of mechanised testing (automation-assisted inspection and the corresponding evaluation of data), higher reliability standards are believed to have been achieved. However, human inspectors, and thus human factors, still play an important role throughout this process and the risks involved in this application are unknown. The aim of this study was to explore for the first time the risks associated with mechanised NDT and find ways of mitigating their effects on the inspection performance. Hence, the objectives were to identify and Analyse potential risks in mechanised NDT and devise measures against them. To address those objectives, a risk assessment in form of a Failure Modes and Effects Analysis (FMEA) was conducted. This analysis revealed potential for failure during both the acquisition and evaluation of NDT data that could be assigned to human, technology, and organisation. Since the existing preventive measures were judged to be insufficient to defend the system from identified failures, new preventive measures were suggested. KW - NDT KW - Human factors KW - Risk assessment KW - FMEA KW - Reliability KW - Human error PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-463325 SN - 1616-069X IS - 161 SP - 52 EP - 62 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) CY - Berlin AN - OPUS4-46332 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ratkovac, Mirjana A1 - Gerards-Wünsche, Paul A1 - Thiele, Marc A1 - Brackrock, Daniel A1 - Stamm, Michael T1 - Detection and monitoring of the fatigue crack growth on welds – Application-oriented use of NDT methods N2 - Early detection of fatigue cracks and accurate measurements of the crack growth play an important role in the maintenance and repair strategies of steel structures exposed to cyclic loads during their service life. Observation of welded connections is especially of high relevance due to their higher susceptibility to fatigue damage. The aim of this contribution was to monitor fatigue crack growth in thick welded specimens during fatigue tests as holistically as possible, by implementing multiple NDT methods simultaneously in order to record the crack initiation and propagation until the final fracture. In addition to well-known methods such as strain gauges, thermography, and ultrasound, the crack luminescence method developed at the Bundesanstalt für Materialforschung und -prüfung (BAM), which makes cracks on the surface particularly visible, was also used. For data acquisition, a first data fusion concept was developed and applied in order to synchronize the data of the different methods and to evaluate them to a large extent automatically. The resulting database can ultimately also be used to access, view, and analyze the experimental data for various NDT methods. During the conducted fatigue tests, the simultaneous measurements of the same cracking process enabled a comprehensive comparison of the methods, highlighting their individual strengths and limitations. More importantly, they showed how a synergetic combination of different NDT methods can be beneficial for implementation in large-scale fatigue testing but also in monitoring and inspection programs of in-service structures - such as the support structures of offshore wind turbines. T2 - Fatigue Design 2023 (FatDes 2023) CY - Senlis, France DA - 29.11.2023 KW - Fatigue KW - Welded KW - NDT KW - Crack growth PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600238 DO - https://doi.org/10.1016/j.prostr.2024.03.062 VL - 57 SP - 560 EP - 568 PB - Elsevier B.V. AN - OPUS4-60023 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Holstein, R. A1 - Müller, Christina T1 - Analyzing the reliability of non-destructive tests using the modular modell - a practical approach N2 - Non-destructive testing is an important tool to guarantee the safety of railway traffic. The infrastructure with tracks, switches and sleepers is regularly tested, the locomotives and wagons with their wheels, bogies and axles as well. Many years of experience and some events lead in Germany to a good practice in testing the railway components. Now, European authorities are drafting a system of common requirements and standards for the European Railway Market. The German practice combines an intensive training of the NDT-personnel including sufficient time for practical exercises with organizational measures of the companies, responsible for rolling stock and infrastructure. Through the example of UT-testing of railway axles it will be shown, how training and organizational measures influence the reliability of such testing. T2 - 19th World Conference on Non-Destructive Testing CY - München, Germany DA - 13.06.2016 KW - NDT KW - Reliability KW - Modular model KW - Railway KW - Human factors PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-375712 UR - http://www.ndt.net/article/wcndt2016/papers/mo1d4.pdf SP - id 19519, 1 EP - 6 AN - OPUS4-37571 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -