TY - JOUR A1 - Krause, Martin A1 - Mayer, K. A1 - Chinta, P.K. A1 - Effner, Ute T1 - Ultrasonic imaging of defects in building elements made from timber JF - Advanced materials research N2 - There is a great demand for non-destructive testing methods for quality assurance and to assess the safety and durability of wooden structures. Ultrasonic echo technique with shear waves in the frequency range of 50 kHz is one of those promising methods and is already frequently applied for usual and glued laminated timber. The article describes the development and first results for an imaging method for this purpose. The highly anisotropic properties of the ultrasonic velocity have to be considered. A 3D-SAFT (Synthetic Aperture Focusing Technique) imaging scheme is developed initially for synthetic data resulting from modelling the elastic wave propagation. The main part of the paper describes the experimental validation of this evaluation technique by experimental studies applying automated ultrasonic scanning techniques. 3D ultrasonic imaging results are described for test specimens made from pine and spruce wood. Another object of investigation was a pedestrian bridge made from siberian larch. KW - Ultrasonic echo KW - Imaging KW - SAFT reconstruction calculation KW - Anisotropic wave propagation KW - EFIT modelling KW - Glued-laminated timber (glulam) PY - 2013 DO - https://doi.org/10.4028/www.scientific.net/AMR.778.312 SN - 1022-6680 SN - 1662-8985 VL - 778 SP - 312 EP - 320 PB - Trans Tech Publ. CY - Zurich AN - OPUS4-29088 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krause, Martin A1 - Milmann, Boris A1 - Mielentz, Frank A1 - Streicher, Doreen A1 - Redmer, Bernhard A1 - Mayer, K. A1 - Langenberg, K.-J. A1 - Schickert, M. T1 - Ultrasonic Imaging Methods for Investigation of Post-tensioned Concrete Structures: A Study of Interfaces at Artificial Grouting Faults and Its Verification JF - Journal of nondestructive evaluation N2 - This paper presents the progress of successful location of grouting faults in tendon ducts with ultrasonic imaging. The examples were obtained in the research group FOR 384 funded by DFG (German Research Foundation). The co-operation of experimental research and modeling allowed imaging and identification of grouted and ungrouted areas of tendon ducts (including strands) in a large test specimen (40 m²). In addition to the criteria for indicating grouting faults in post-tensioned ducts known until now the phase evaluation of reflected ultrasonic pulses is described. Experiments and modeling of wave propagation are presented for reflections at metal plates in concrete (thickness range 0.5 mm to 40 mm) and for tendon ducts including strands. The main part of the progress was achieved by automated measurements using dry contact transducers, 3D-SAFT reconstruction including phase evaluation and modeling considering wave propagation for typical elastic parameters and exact experimental site conditions. The results for shear waves as well as for pressure waves are compared in the frequency range from 50 kHz to 120 kHz. KW - Non-destructive testing KW - Tendons KW - Prestressed concrete bridges KW - Ultrasonic echo KW - Reconstruction calculation KW - 3D-SAFT KW - Modeling (EFIT) PY - 2008 DO - https://doi.org/10.1007/s10921-008-0033-5 SN - 0195-9298 SN - 1573-4862 VL - 27 IS - 1-3 SP - 67 EP - 82 PB - Plenum Press CY - New York, NY AN - OPUS4-17922 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Varga, E. A1 - Glauner, T. A1 - Köppen, Robert A1 - Mayer, K. A1 - Sulyok, M. A1 - Schuhmacher, R. A1 - Krska, R. A1 - Berthiller, F. T1 - Stable isotope dilution assay for the accurate determination of mycotoxins in maize by UHPLC-MS/MS JF - Analytical and bioanalytical chemistry N2 - A fast, easy-to-handle and cost-effective analytical method for 11 mycotoxins currently regulated in maize and other cereal-based food products in Europe was developed and validated for maize. The method is based on two extraction steps using different acidified acetonitrile–water mixtures. Separation is achieved using ultrahigh-performance liquid chromatography (UHPLC) by a linear water–methanol gradient. After electrospray ionisation, tandem mass spectrometric detection is performed in dynamic multiple reaction monitoring mode. Since accurate mass spectrometric quantification is hampered by matrix effects, uniformly [13C]- labelled mycotoxins for each of the 11 compounds were added to the sample extracts prior to UHPLC-MS/MS analysis. Method performance parameters were obtained by spiking blank maize samples with mycotoxins before as well as after extraction on six levels in triplicates. The twofold extraction led to total recoveries of the extraction steps between 97%and 111% for all target analytes, including fumonisins. The [13C]- labelled internal standards efficiently compensated all matrix effects in electrospray ionisation, leading to apparent recoveries between 88% and 105% with reasonable additional costs. The relative standard deviations of the whole method were between 4% and 11% for all analytes. The trueness of the method was verified by the measurement of several maize test materials with well-characterized concentrations. In conclusion, the developed method is capable of determining all regulated mycotoxins in maize and presuming similar matrix effects and extraction recovery also in other cerealbased foods. KW - Mycotoxins KW - Stable isotope dilution assay KW - Multi-target analysis KW - Ultrahigh-performance liquid chromatography KW - Tandem mass spectrometry KW - Maize PY - 2012 DO - https://doi.org/10.1007/s00216-012-5757-5 SN - 1618-2642 SN - 1618-2650 VL - 402 IS - 9 SP - 2675 EP - 2686 PB - Springer CY - Berlin AN - OPUS4-25640 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schulze, S. A1 - Mayer, K. A1 - Krause, Martin T1 - Spannbetonuntersuchung mit bildgebenden Ultraschallecho-Verfahren JF - Beton- und Stahlbetonbau N2 - Beim Einsatz von Ultraschallecho-Methoden in der zerstörungsfreien Prüfung im Bauwesen stellt die Untersuchung von Spannbetonkonstruktionen eine der anspruchsvollsten Aufgaben für Wissenschaft und Technik dar. Das inhomogene Gefüge aus Beton, schlaffer Bewehrung und – aus Hüllrohr, Spannlitzen und Verpressmörtel bestehenden – Spanngliedern erfordert eine Optimierung von Messtechnik und Auswertesoftware, um verwertbare Aussagen zum Verpresszustand der Hüllrohre zu erhalten. Der vorliegende Beitrag beschreibt die Grundlagen der bildgebenden Darstellung von US-Echo-Daten, die Untersuchung und Datenauswertung an Probekörpern sowie ein Fallbeispiel aus der Praxis. Dabei erweist sich insbesondere die Phasenauswertung zur qualitativen Unterscheidung von Reflektoren als nützlich. Das Prinzip wird erläutert, und es werden Teile eines interaktiven, auf der SAFT-Methode basierenden Softwarepakets vorgestellt. Mit dieser Software können die großflächig gewonnenen Ultraschalldaten auf herkömmlichen PCs oder mobilen Computern zu zwei- und dreidimensionalen Rekonstruktionen berechnet, analysiert und visualisiert werden. Ausgewertet wurden Daten, die mit automatisierten Messsystemen an kleinformatigen Laborprobekörpern und großen Testwänden gewonnen wurden. Im Rahmen der praktischen Anwendung konnten unter Verwendung der vorgestellten Verfahren an einem Spannglied die Lage eines Hüllrohrverstopfers lokalisiert und die Ausdehnung der Blockadestelle eingegrenzt werden.---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Investigation of prestressed concrete using the imaging ultrasonic echo method – Application of phase evaluation for the distinction of reflectors: The application of ultrasound methods for the non-destructive assessment of pre-stressed concrete members is one of the biggest challenges in the field of non-destructive testing in civil engineering. The inhomogeneous composition of concrete, reinforcement and tendons, which itself consist of ducts, steel wires and grouting material, requires an optimisation of measuring technique and analysis software to gain reliable information about the grouting condition of the ducts. This article describes the fundamentals of the visualisation of ultrasound echo data, the investigation and data analysis at specimen and a case study. Here especially the phase evaluation proves to be very useful for the distinction of reflectors. The basic principle is explained and parts of an interactive software module, which is based on the SAFT method, is presented. With this software it is possible to calculate, analyse and visualise 2D and 3D reconstructions of large ultrasound data sets with conventional PCs or mobile computers. Data has been analysed, which were recorded with automatic measurement systems at small scale laboratory specimens and a large scale testing wall. In the frame of the practical application it was possible to localise the position and extent of a blockade within a duct. KW - Ultraschallecho KW - Zerstörungsfreie Prüfung im Bauwesen KW - ZfPBau KW - Ultraschallecho-Methode KW - Bildgebende Auswertung KW - SAFT-Rekonstruktion KW - Phasenauswertung KW - Spannbeton KW - Verpresszustand KW - Rekonstruktionssoftware KW - Non-destructive testing in civil engineering (NDT-CE) KW - Ultrasound echo method KW - Imaging methods KW - SAFT reconstruction KW - Phase evaluation KW - Pre-stressed concrete KW - Grouting condition KW - Reconstruction software KW - Bauwerkserhaltung/Sanierung PY - 2013 DO - https://doi.org/10.1002/best.201300062 SN - 0005-9900 SN - 1437-1006 VL - 108 IS - 12 SP - 845 EP - 853 PB - Ernst CY - Berlin AN - OPUS4-29838 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mielentz, Frank A1 - Feller, Viktor A1 - Krause, Martin A1 - Orglmeister, R. A1 - Mayer, K. T1 - Schallfeldmodellierung von Ultraschall-Transversalwellen-Prüfköpfen - Modellierung von Prüfkopfarrays mit der Elastodynamischen Finiten Integrationstechnik und der Punktquellensynthese JF - Materials Testing N2 - Ultraschallmessverfahren werden seit Langem erfolgreich für Prüfaufgaben, wie zum Beispiel die Ermittlung von Bauteilgeometrien, im Bauwesen eingesetzt. Um die Schallbündelung der Prüfköpfe zu verbessern, werden oft mehrere Prüfköpfe in einem Array angeordnet. Für die Entwicklung der Prüfkopfarrays ist es zweckmäßig, mithilfe von Modellierungen den Einfluss der Arraygröße, der Anordnung der Einzelprüfköpfe im Array und der Prüffrequenz auf das Schallfeld zu untersuchen. Dazu werden in der Praxis erfolgreich Modellierungen auf der Basis der Elastodynamischen Finiten Integrationstechnik (EFIT) und der Punktquellensynthese angewendet. Beim Aufbau der Arrays kommen zurzeit immer häufiger Transversal-Punktkontaktprüfköpfe zur Anwendung. Daher wird bei der Beschreibung der Schallfeldberechnung insbesondere auf die der Transversalwellenprüfköpfe eingegangen und mithilfe von Modellierungen und Experimenten gezeigt, wie sich die Prüfkopfpositionierung auf die Richtcharakteristik auswirkt. KW - Ultraschall KW - Beton KW - Transversalwellen KW - Modellierung KW - Punktquellensynthese KW - Elastodynamische Finite Integrationstechnik KW - EFIT PY - 2013 DO - https://doi.org/10.3139/120.110510 SN - 0025-5300 VL - 55 IS - 11-12 SP - 856 EP - 864 PB - Hanser CY - München AN - OPUS4-29685 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Effner, Ute A1 - Mielentz, Frank A1 - Niederleithinger, Ernst A1 - Friedrich, C. A1 - Mauke, R. A1 - Mayer, K. T1 - Prüfung von Abdichtbauwerken für Endlager auf Risse – eine Herausforderung JF - Materialwissenschaft und Werkstofftechnik N2 - Im Jahr 2011 hat der Bundestag in Deutschland den Ausstieg aus der Kernenergie beschlossen. Der angefallene Abfall wird mehr als hunderttausend Jahre eine derartig hohe Aktivität besitzen, dass er eine erhebliche Gefahr für nachfolgende Generationen darstellen kann. Dieser radioaktive Abfall soll in tiefen geologischen Formationen (z.B. Salz, Ton oder Kristallin) sicher endgelagert werden. Die Endlager werden mittels sogenannter geotechnischer Abdichtbauwerke (Schachtbzw. Streckenverschlüsse) verschlossen, wofür u.a. Zement- oder Sorel-basierte Baustoffe (Betone) in Frage kommen. Die Beschreibung des Dichtvermögens dieser Bauwerke ist unabdingbar. In der Forschungsphase werden verschiedene Werkstoffe untersucht und Methoden für die zerstörungsfreie Untersuchung der Bauwerke als Mittel der Qualitätsprüfung entwickelt. Hierbei ist der Nachweis der Rissfreiheit bzw. die Detektion möglicher Risse ein vorrangiges Thema. In den letzten Jahren konnten bereits umfangreiche Erfahrungen mit der Untersuchung von in-situ-Versuchsobjekten in Realmaßstab gesammelt werden. Die Messungen wurden im Endlager für radioaktive Abfälle Morsleben am in-situ-Versuch “Abdichtbauwerk im Steinsalz” und in der Grube Teutschenthal am Großversuch GV2 durchgeführt. Es ist gelungen mit einem neu entwickelten Ultraschall-Messsystem Eindringtiefen bis ca. 9,0 m zu realisieren. Die Messungen mit dem Large Aperture Ultrasonic System in Kombination mit der Rekonstruktion-Methode Synthetic Aperture Focusing Technique zeigen, dass die zerstörungsfreie Prüfung von Abdichtbauwerken möglich und die Nutzung des Messsystems zur Qualitätssicherung bei der Erstellung der Verschlussbauwerke vielversprechend ist. N2 - In 2011, the German Bundestag decided to phase out nuclear energy. The resulting waste will remain highly radioactive for many hundreds of thousands of years and represents a considerable danger for future generations. This radioactive waste is to be safely disposed of in deep geological formations (e.g. salt, clay or crystalline). The repositories will be sealed by means of engineered barrier systems. The impermeability of these structures is indispensable. In the current research phase, various materials are being investigated and methods for monitoring the structures are being developed. In this context, the investigation of cracks is a priority topic. In recent years, BAM has gained extensive experience in the investigation of in-situ test objects in full scale. The measurements were performed in the Morsleben repository for radioactive waste at the test structure for the in-situ experiment "Sealing structure in rock salt" and in the Teutschenthal mine at the large-scale GV2 test structure. With a newly developed ultrasonic measuring system it has been possible to achieve penetration depths of up to approx. 9.0 m. Measurements with the Large Aperture Ultrasonic System in combination with the Synthetic Aperture Focusing Technique reconstruction method show that the non-destructive testing of sealing structures is possible and the use of the measuring system for quality assurance in the construction of sealing structures is promising. KW - Abdichtbauwerk / Verschlussbauwerk KW - Zerstörungsfreie Prüfung KW - Large Aperture Ultrasonic System KW - Synthetic Aperture Focusing Technique KW - Ultraschall-Echo-Verfahren PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520298 DO - https://doi.org/10.1002/mawe.202000118 SN - 1521-4052 VL - 52 IS - 1 SP - 19 EP - 31 PB - Wiley-VCH GmbH CY - Weinheim AN - OPUS4-52029 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krause, Martin A1 - Mayer, K. A1 - Friese, Martin A1 - Milmann, Boris A1 - Mielentz, Frank A1 - Ballier, G. T1 - Progress in ultrasonic tendon duct imaging JF - European journal of environmental and civil engineering N2 - Ultrasonic imaging of tendon ducts enables the precise localisation of grouting faults in many cases. Additionally to well known criteria for detecting grouting faults in tendon ducts recently new possibilities were developed. Two main effects influence the complex behaviour of wave propagation and reflection: a) different arrangement and number of strands or internal rebars; b) superposition of reflecting signals and different wave modes propagating into the interface region around the tendon duct. In order to understand the experimental results, EFIT modelling is performed (EFIT: Elastodynamic Finite Integration Technique). KW - Ultrasonic imaging KW - Prestressed concrete structures KW - Reconstruction calculation KW - SAFT KW - EFIT modelling PY - 2011 DO - https://doi.org/10.3166/ejece.15.461-485 SN - 1964-8189 VL - 15 IS - 4 SP - 461 EP - 485 PB - Lavoisier CY - Paris AN - OPUS4-23853 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mayer, K. A1 - Milmann, Boris A1 - Krause, Martin A1 - Mielentz, Frank T1 - Methode zum Nachweis von Verpressfehlern in Spannbeton durch Phasenauswertung bei Ultraschallecho-Verfahren JF - ZfP-Zeitung KW - Ultraschall-Echo-Verfahren KW - Verpressfehler KW - Spannbeton KW - Hüllrohr KW - Brücken PY - 2008 SN - 1616-069X SN - 0948-5112 VL - 112 IS - 12 SP - 37 EP - 40 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung CY - Berlin AN - OPUS4-18685 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wiggenhauser, Herbert A1 - Samokrutov, A.A. A1 - Mayer, K. A1 - Krause, Martin A1 - Alekhin, S. G. A1 - Elkin, V. T1 - LAUS - Large aperture ultrasonic system - for testing thick concrete structures JF - The e-journal of nondestructive testing & ultrasonics N2 - A Large Aperture UltraSonic (LAUS) system has been designed and built for testing thick concrete structures. The scalable system consists of twelve ultrasonic units, each hosting 32 individual shear wave transducers with mechanical dry point contact (DPC) to the concrete surface. The twelve units are attached to the concrete surface using a vacuum case which holds them in place during operation. Each LAUS unit can be placed individually depending on the surface condition and optimal ultrasonic condition, e.g. rebar position. Air pressure is supplied to each unit through an air hose. The following extended abstract is a short version of an article to be published in the special edition of ASCE JIS that will describe the outline of the system, the principle of functioning, the data processing and adapted reconstruction calculation based on SAFT as well as the system performance during first applications. T2 - NDT-CE 2015 - International symposium non-destructive testing in civil engineering CY - Berlin, Germany DA - 15.09.2015 KW - Ultrasonic imaging KW - Linear array KW - Reconstruction calculation (SAFT) PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-345383 UR - http://www.ndt.net/?id=18313 SN - 1435-4934 VL - 20 IS - 11 SP - 1 EP - 4 PB - NDT.net CY - Kirchwald AN - OPUS4-34538 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wiggenhauser, Herbert A1 - Samokrutov, A A1 - Mayer, K A1 - Krause, Martin A1 - Alekhin, S. G. A1 - Elkin, V T1 - Large aperture ultrasonic system for testing thick concrete structures JF - Journal of Infrastructure Systems N2 - A Large Aperture UltraSonic system (LAUS) has been designed and built for testing thick concrete structures. The scalable system consists of twelve ultrasonic units, each hosting 32 individual shear wave transducers with mechanical dry point contact (DPC) to the concrete surface. The twelve units are attached to the concrete surface using a vacuum case which holds them in place during operation. Each LAUS unit can be placed individually on the surface to achieve optimal ultrasonic condition, e.g. to avoid rebars. For the generation of vacuum, air pressure is supplied to each unit through an air hose. The twelve units define an aperture which is necessary for fast reconstruction of the subsurface structure. The well-known SAFT (Synthetic Aperture Focusing Technique) algorithm has been adopted to this situation, where the individual LAUS units form a linear aperture with not necessarily equidistant spacing between the units. The exact geometrical position of the units, which are individually marked with retroreflective labels, is determined using photographs and image processing. All transducers are synchronized and work either as transmitter or receiver. A full scan consists of 12 * 11 recordings, where each unit acts as transmitter once and all others as receivers. An electronic sub-unit on the back of the ultrasonic device holds the battery and handles data acquisition, synchronization and data communication. A computer is used as base unit which communicates with each LAUS unit for control and data acquisition, the synchronization is performed by a radio modem that uses a special algorithm similar to a digital PLL (phase locked loop). No wire connections are necessary between the units and the base system. The LAUS system is designed to investigate concrete structures with thicknesses in excess of 2 m, depending on the acoustic condition of the object under investigation. Highly reinforced concrete may have less penetration depth. The LAUS provides quasi real time imaging, once the transducers are put in place and the data has been acquired. First measurements on a foundation slab confirm, that the system can register ultrasonic echoes from the back wall at 4 m distance. KW - Ultrasound "Large Aperture" NDT Concrete PY - 2017 DO - https://doi.org/10.1061/(ASCE)IS.1943-555X.0000314 SN - 1076-0342 SN - 1943-555X VL - 23 IS - 1 SP - B4016004-1 EP - B4016004-9 PB - American Society of Civil Engineers (ASCE) CY - Reston, VA 20191-4400 USA AN - OPUS4-39372 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -