TY - CONF A1 - Gaal, Mate A1 - Müller, Christina A1 - Pavlovic, Mato T1 - Design of the BAM-ITEP-Trials 2005 an co-operation with HuMin/MD T2 - BAM-BMVg Seminar CY - Berlin, Germany DA - 2005-04-21 PY - 2005 AN - OPUS4-11392 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Christina A1 - Gaal, Mate A1 - Rosenthal, Martina A1 - Bär, Sylke A1 - Lewis, A. A1 - Bloodworth, T. A1 - Guelle, D. A1 - Wilrich, P.-Th. T1 - ITEP-Test Trials for Detection Reliability Assessment of Metal Detectors N2 - The total reliability of a mine searching system is driven by the triple of intrinsic capability, which describes the physical-technical basis capability, the application and environmental factors and the human factors. Some of them can be determined in laboratory measurements but the human factor and a part of environment conditions and their interaction with the device need to be treated statistically. That is why the test & evaluation procedure described in CEN CWA 14747:2003, includes in addition to parameter tests of metal detectors also the reliability or blind field tests under local conditions with local personnel. A series of three big field trials had been accomplished in the ITEP-project 2.1.1.2 “Reliability Model for Test & Evaluation of Metal Detectors” to specify the optimum conditions for reliable trial results with affordable effort. For each set of specific working conditions, characterized in terms of a combination of one mine type in one soil with one detector handled by local personnel, the searching system will show up a working performance in mine detection rates as a function of mine depth and show up a certain overall false call rate. During the ITEP-trials in Benkovac and Oberjettenberg the authors learnt to determine this function separately for each mine type in each soil, which is especially important for low metal mines in uncooperative soil which will be illustrated for the mine PMA2 in different types of soil. The question of representativeness for field conditions on the one hand and necessary statistical set up for the possibility to distinguish between individual detector performances is still under discussion. KW - Zuverlässigkeit der Minensuche KW - Feldtests KW - Modulares Modell KW - Metalldetektor PY - 2005 UR - http://maic.jmu.edu/journal/8.2/rd/mueller.htm SN - 1533-9440 SN - 1533-6905 N1 - Geburtsname von Rosenthal, Martina: Scharmach, M. - Birth name of Rosenthal, Martina: Scharmach, M. IS - 8.2 SP - 86 EP - 90 CY - Harrisonburg AN - OPUS4-6041 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gaal, Mate A1 - Müller, Christina A1 - Ewert, Uwe A1 - Wilrich, P.-Th. A1 - Spyra, W. T1 - Trial design for testing and evaluation of metal detectors used in humanitarian landmine clearance T2 - ECNDT 2006 9. Europäische Konferenz für Zerstörungsfreie Prüfung CY - Berlin, Germany DA - 2006-09-25 PY - 2006 AN - OPUS4-14202 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gaal, Mate A1 - Müller, Christina T1 - Statistical design of experiments applied to tests of metal detectors used for mine detection T2 - 4th International Probabilistic Symposium CY - Berlin, Germany DA - 2006-10-12 PY - 2006 AN - OPUS4-14200 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Gaal, Mate A1 - Müller, Christina ED - Proske, D. T1 - Statistical design of experiments applied to tests of metal detectors used for mine detection T2 - 4th International Probabilistic Symposium CY - Berlin, Germany DA - 2006-10-12 KW - Zuverlässigkeit in der Minensuche KW - Feldtests KW - Modulares Modell KW - Metalldetektor PY - 2006 SN - 3-00-019232-8 SP - 253 EP - 264 PB - Bundesanstalt für Materialforschung und -prüfung CY - Berlin AN - OPUS4-14297 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gaal, Mate A1 - Müller, Christina A1 - Ewert, Uwe A1 - Wilrich, P.-Th. A1 - Spyra, W. T1 - Trial Design for Testing and Evaluation of Metal Detectors Used in Humanitarian Landmine Clearance T2 - 9th European Conference on NDT CY - Berlin, Germany DA - 2006-09-25 KW - Zuverlässigkeit in der Minensuche KW - Feldtests KW - Modulares Modell KW - Metalldetektor PY - 2006 SN - 3-931381-86-2 SP - 1(?) EP - 10(?) PB - European Federation for Non-Destructive Testing CY - Berlin AN - OPUS4-14420 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - THES A1 - Gaal, Mate T1 - Trial Design for Testing and Evaluation in Humanitarian Mine Clearance N2 - This thesis proposes a design of experiment for testing and evaluation of the equipment and the methods used in manual mine clearance. The thesis is based on several metal detector trials and a trial of manual demining methods. The core of this dissertation comprises four metal detector trials performed in Germany and Croatian in 2003 and 2005. The purpose of these trials was to investigate the feasibility of the tests described in the CWA (Comité Européende Normalisation/CEN/Workshop Agreement) 14747:2003, the standard for testing metal detectors for humanitarian demining. The goals of the trials were: to find an appropriate design of experiment for testing metal detectors; to establish the use of ROC diagrams (Receiver Operating Characteristics) and POD curves (Probability of Detection) in the analysis of the experimental results; and to gain practical experience in organising and conducting metal detector trials. Apart of this thesis is devoted to a trial of manual demining methods performed in Mozambique in 2004. The main goal of that trial was to compare the speed of various manual demining methods, including the most common excavation methods. The outcome of this work is the proposals and recommendations for an update of the standard for testing metal detectors CWA 14747:2003. Maximum detection height measurements were performed as a part of the metal detector trial carried out in Croatiain2005. The results reveal a high variability of the maximum detection height. This high variability needs to be taken into account in all experiments. Apart of the variability is caused by the differences between the operators and by the setup of the metal detector. It is therefore recommended that two kinds of experiments with the maximum detection height as a response variable are defined in the next update of CWA 14747:2003. The first kind should include the setup, the soil and the operator as factors in the design of experiment. The in-soil measurements with the same detector should be performed with repeated setups and with several operators. The second kind of experiments should be experiments evaluating the influence of other predictor variables. In those experiments, it is recommended to perform one-factor or multiple-factor in-air measurements with the operators and the setup as a block. The main part of the metal detector trials described in this thesis was the detection reliability tests. Detection reliability tests as described in CWA14747:2003 come closest to representing the real field conditions in demining. They include many environmental influences and, most importantly, many of the human factor influences. However, each test design is a compromise between fully representative conditions and cost effectiveness. In this thesis, a fractional factorial design based on the Graeco-Latin square is proposed as a solution to the experimental problem. The results are reported in the form of ROC diagrams and POD curves. The crossover design enables each operator to work with fewer detector models with in a certain time. The variations of the design enabled an unbiased comparison of detectors in each soil and with each target model separately. It is recommended that the solutions proposed in this thesis be incorporated in the standard CWA14747:2003. It has been shown that maximum detection heights measurements provide the information about the best possible performance of a metal detector in are liability test. T3 - BAM Dissertationsreihe - 27 KW - Minenräumung KW - demining KW - Metalldetektor KW - metal detector PY - 2007 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-1310 SN - 978-3-9811655-6-2 SN - 1613-4249 VL - 27 SP - 1 EP - 158 PB - Bundesanstalt für Materialforschung und -prüfung (BAM) CY - Berlin AN - OPUS4-131 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gaal, Mate A1 - Müller, Christina T1 - Versuchsplan für Prüfung und Bewertung von Metalldetektoren für die Minenräumung T2 - DGZfP-Jahrestagung 2007 (ZfP in Forschung, Entwicklung und Anwendung) CY - Fürth, Germany DA - 2007-05-14 PY - 2007 AN - OPUS4-14834 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gaal, Mate A1 - Döring, Joachim A1 - Brekow, Gerhard T1 - Anregung von Lambwellen mit Luftultraschall T2 - Fachmesse "Sensor und Test 2009" CY - Nuremberg, Germany DA - 2009-05-26 PY - 2009 AN - OPUS4-25202 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Müller, Christina A1 - Bertovic, Marija A1 - Gaal, Mate A1 - Heidt, Heinrich A1 - Pavlovic, Mato A1 - Rosenthal, Martina A1 - Takahashi, K. A1 - Pitkänen, J. A1 - Ronneteg, U. T1 - Progress in evaluating the reliability of NDE systems - Paradigm shift N2 - The paper will give an overview of new methodology for evaluating the reliability of NDE systems accurately, reliably and efficiently in accordance with the specific requirements of industrial application. After a review of the substantive issues from the previous workshops, the go forward guidance from these interactions is considered. At the beginning of the reliability analysis, the actual safety demands have to be defined in order to fit the investigation to the level of risk when the component would fail. Next, all the essential influencing parameters need to be documented and transferred to an appropriate design of experiments (DOE) to determine the reliability in terms of a qualitative assessment for lower risk or in terms of a quantitative probability of detection (POD) or ROC (Receiver Operating Characteristics) curves for higher safety demands. A new paradigm is offered to consider the POD or reliability of the system as a function of the configuration of input variables and use it for optimisation rather than for a final judgement. An advantage for the end user is also to sample all single PODs to an integral 'Volume POD' of a part. Among the influencing parameters, the human factor is the most important one. A systematic psychological approach shall help to find out where the bottlenecks are but most importantly to provide best possible working conditions for the human inspectors. T2 - 4th European-American workshop on reliability of NDE CY - Berlin, Germany DA - 2009-06-24 KW - Zuverlässigkeit von ZfP-Systemen KW - Multiparameter POD PY - 2009 UR - http://www.ndt.net/article/reliability2009/Inhalt/we1a2.pdf SN - 978-3-940283-17-7 IS - DGZfP-BB 116 SP - 1 EP - 13 AN - OPUS4-20616 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Christina A1 - Pavlovic, Mato A1 - Bertovic, Marija A1 - Gaal, Mate A1 - Heidt, Heinrich A1 - Rosenthal, Martina A1 - Takahashi, K. A1 - Pitkänen, J. A1 - Ronneteg, U. T1 - Fortschritte bei der Bewertung der Zuverlässigkeit von ZfP-Systemen N2 - Es werden die Fortschritte bei der Bewertung der Zuverlässigkeit von ZfP-Systemen in den vergangenen 10 Jahren vorgestellt. Der modulare Ansatz bzw. die systematische Auflistung aller wesentlichen Einflussfaktoren stehen am Anfang jeder Bewertung, die jeweils spezifisch für einen industriellen bzw. Feldeinsatz angelegt wird. Weiterhin legt die zu Grunde liegende Sicherheitsanforderung fest, ob ein exaktes quantitatives statistisches Ergebnis z. B. für die Fehlergröße, die mit hoher Sicherheit detektiert wird angestrebt wird oder ob man sich mit einer qualitativen Abschätzung zufrieden geben kann. Moderne Werkzeuge wie das 'Design of Experiments' (Statistische Versuchsplanung), die Volumen-POD für ein Bauteil als ganzes oder auch die systematische psychologische Betrachtung des menschlichen Faktors unterstützen die Treffsicherheit der Untersuchung für den gewünschten Einsatzfall. Die Ergebnisse der ZfP-Prüfungen können immer nur so gut sein, wie der Mensch mit den Bedingungen zurechtkommt. Weiterhin kann die POD im Zusammenhang mit den Prozessparametern als helfendes Optimierungswerkzeug eingesetzt werden und nicht als endgültige Be(Ver)urteilung. Es werden Beispiele aus Bereichen der Energieerzeugung und Endlagerung präsentiert. T2 - DGZfP-Jahrestagung 2009 CY - Münster, Deutschland DA - 2009-05-18 KW - POD KW - ROC KW - Paradigmenshift KW - Optimierung KW - Human factor PY - 2009 UR - http://www.ndt.net/article/dgzfp2009/Inhalt/mo3c2.pdf SN - 978-3-940283-16-0 IS - DGZfP-BB 115 (Mo.3.C.2) SP - 1 EP - 9 AN - OPUS4-20619 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Bertovic, Marija A1 - Gaal, Mate A1 - Müller, Christina A1 - Fahlbruch, B. T1 - Investigating human factors in manual ultrasonic testing: Testing the human factor model N2 - The human factors approach relies on understanding the properties of human capability and limitations under various conditions and the application of that knowledge in designing and developing safe systems. Following the principles of MTO (Man Technology Organization) approach, emphasis should be given to the way people interact with technical as well as organizational systems. A model describing human factor influences in relation to the performance shaping factors and their effect on the manual ultrasonic inspection performance had been built and a part of it empirically tested. The experimental task involved repeated inspection of 18 flaws according to the standard procedure under no, middle and high time pressure. Stress coping strategies, mental workload of the task, stress reaction and organizational factors have been measured. The results have shown that time pressure, mental workload and experience influence the quality of the inspection performance. Organizational factors and their influence on the inspection results were rated as important by the operators. However, further research is necessary into the effects of stress. T2 - 4th European-American workshop on reliability of NDE CY - Berlin, Germany DA - 2009-06-24 KW - Human factors KW - Time pressure KW - Nuclear power plants KW - Ultrasonic testing PY - 2009 UR - http://www.ndt.net/article/reliability2009/Inhalt/th4a3.pdf SN - 978-3-940283-17-7 IS - DGZfP-BB 116 SP - 1 EP - 8 AN - OPUS4-20615 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Gaal, Mate A1 - Bertovic, Marija A1 - Müller, Christina A1 - Zickler, S. A1 - Fahlbruch, B. A1 - Spokoiny, V. A1 - Schombach, D. A1 - Just, Tilman A1 - Cramer, H.-J. T1 - Untersuchungen zum Einfluss menschlicher Faktoren auf das Ergebnis von zerstörungsfreien Prüfungen, Möglichkeiten zur Minimierung dieses Einflusses und Bewertung der Prüfergebnisse KW - Menschliche Faktoren KW - ZfP KW - Manuelle Ultraschallprüfung KW - WkP KW - KKW PY - 2009 IS - BfS-Projekt SR 2514 / Endbericht SP - 1 EP - 79 CY - Salzgitter AN - OPUS4-26081 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gaal, Mate A1 - Döring, Joachim A1 - Brekow, Gerhard A1 - Kreutzbruck, Marc A1 - Prager, Jens T1 - Fehlernachweis mit Plattenwellen und Luftultraschall T2 - DGZfP-Jahrestagung 2009 CY - Münster, Germany DA - 2009-05-18 PY - 2009 AN - OPUS4-19811 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Takahashi, K. A1 - Gaal, Mate A1 - Gülle, D. T1 - Data analysis and performance evaluation of japanese dual-sensor systems tested in Croatia KW - Test KW - Dual sensor KW - Landmine detection PY - 2009 UR - http://maic.jmu.edu/JOURNAL/13.3/randd/takahashi_etal/takahashi_etal.htm IS - 13.3 SP - 1 EP - 6 PB - Mine action info center/JMU AN - OPUS4-21110 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 - CONF A1 - Gaal, Mate A1 - Döring, Joachim A1 - Brekow, Gerhard A1 - Kreutzbruck, Marc T1 - Detection of Flaws with Lamb Waves and Air-Coupled Ultrasound T2 - 5th International Workshop NDT in Progress CY - Prague, Czech Republic DA - 2009-10-12 PY - 2009 AN - OPUS4-20292 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 - Gaal, Mate A1 - Döring, Joachim A1 - Bartusch, Jürgen A1 - Brekow, Gerhard T1 - Einsatz von Luftultraschall-Sensoren mit geringer akustischer Impendanz T2 - 36th Annual Conference on Acoustic - DAGA 2010 CY - Berlin, Germany DA - 2010-03-15 PY - 2010 AN - OPUS4-25203 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gaal, Mate A1 - Döring, Joachim A1 - Bartusch, Jürgen A1 - Brekow, Gerhard T1 - Entwicklung von Luftultraschall-Sensoren mit geringer akustischer Impedanz T2 - 15. ITG-/GMA-Fachtagung "Sensoren und Messsysteme 2010" CY - Nuremberg, Germany DA - 2010-05-18 PY - 2010 AN - OPUS4-21634 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gaal, Mate A1 - Döring, Joachim A1 - Bartusch, Jürgen A1 - Brekow, Gerhard T1 - Einsatz von Luftultraschall-Sensoren mit geringer akustischer Impedanz T2 - DAGA 2010 - 36. Jahrestagung für Akustik CY - Berlin, Deutschland DA - 2010-03-15 KW - Luftultraschall KW - Sensor KW - Akustische Impedanz KW - Polypropylen PY - 2010 SN - 978-3-9808659-8-2 SP - 1041 EP - 1042 CY - Berlin AN - OPUS4-26402 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gaal, Mate A1 - Döring, Joachim A1 - Bartusch, Jürgen A1 - Brekow, Gerhard T1 - Entwicklung von Luftschall-Sensoren mit geringer akustischer Impedanz T2 - Sensoren und Messsysteme 2010 - 15. ITG/GMA-Fachtagung CY - Nürnberg, Deutschland DA - 2010-05-18 KW - Luftultraschall KW - Sensor KW - Akustische Impedanz KW - Polypropylen PY - 2010 SN - 978-3-8007-3260-9 IS - A9/Paper 48 SP - 275 EP - 279 PB - VDE Verlag GmbH CY - Berlin, Offenbach AN - OPUS4-26407 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 - 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 - Gaal, Mate A1 - Döring, Joachim A1 - Bartusch, Jürgen A1 - Brekow, Gerhard A1 - Kreutzbruck, Marc A1 - Beck, Uwe A1 - Weise, Matthias A1 - Bovtun, V. T1 - Parameter reproducibility of polypropylene ferroelectret transducers for air-coupled ultrasonic testing T2 - IEEE International Ultrasonics Symposium 2011 CY - Orlando, FL, USA DA - 2011-10-18 PY - 2011 AN - OPUS4-25201 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bertovic, Marija A1 - Gaal, Mate A1 - Müller, Christina A1 - Fahlbruch, B. A1 - Schombach, D. T1 - Einfluss des Zeitdrucks auf die manuelle Ultraschallprüfung. Untersuchung zu menschlichen Faktoren auf die Ergebnisse zerstörungsfreier Prüfungen N2 - Die übergeordnete Zielsetzung unserer Untersuchung bestand darin, am Beispiel von Prüfungen mit Ultraschall eine belastbare Aussage zum Einfluss der Arbeitsbedingungen des Prüfers auf die Qualität der Ergebnisse von zerstörungsfreien Prüfungen zu ermitteln und Möglichkeiten zur Minimierung ungünstiger Einflussfaktoren aufzuzeigen. Der Schwerpunkt der Untersuchung wurde auf die manuelle Ultraschallprüfung gelegt und der Faktor 'Zeitdruck' (in drei Stufen variiert) als die zu variierende physische Einflussgröße gewählt. Die Variation des Faktors Zeitdruck wurde gemäß dem Prozessmodell von der Erhebung psychologischer Faktoren, die das Individuum und die Organisation beschreiben, begleitet. Die Ultraschallprüfungen erfolgten mit zehn Prüfern am Großbehälter und an Vergleichskörpern mit eingebrachten Testfehlern (Nuten, Risse). Die ausgewählten Fehler waren typisch für Prüfaufgaben, die bei wiederkehrenden Ultraschallprüfungen in Kernkraftwerken von den Prüfern zu lösen sind. Die Prüfaufgabe bestand darin, die in den vorgegebenen Prüfabschnitten vorhandenen Reflektoren aufzufinden und deren Amplituden, Ortskoordinaten und Längenerstreckungen zu ermitteln. Als Bewertungsmaßstab für die Qualität der Prüfaussage und für den Einfluss des menschlichen Faktors diente die Präzision der gemessenen Werte. Die Ergebnisse zeigen einen hohen Einfluss des menschlichen Faktors auf das Prüfergebnis und eine Einwirkung des Zeitdrucks besonders auf die Präzision der Messwerte. Hierbei war die Wirkung des individuell wahrgenommenen Zeitdrucks zusammen mit der psychischen Arbeitsbeanspruchung signifikant. Es wurde unter anderem herausgearbeitet, dass durch eine gute Vorbereitung auf die Prüfung, z.B. durch die sorgfältige Einweisung und ein vorgeschaltetes Fertigkeitstraining an Vergleichskörpern, die Zuverlässigkeit der Prüfergebnisse verbessert werden kann. Insgesamt hatte der Faktor 'Organisation' neben der 'Erfahrung' einen hohen Einfluss auf das Leistungsvermögen der Prüfer. Die Projektergebnisse wurden im Abschlussbericht des Forschungsvorhabens SR2514 dargestellt, es wurden drei Empfehlungen zur Vorbereitung und Einweisung der Prüfer, zur Stärkung der Verantwortung der Prüfaufsicht und zum 4-Augen-Prinzip formuliert. Die Empfehlungen wurden in der KTA- Regel 3201.4 'Komponenten des Primärkreises von Leichtwasserreaktoren; Teil 4: Wiederkehrende Prüfungen und Betriebsüberwachung (RÄE Fassung 2010-11)', umgesetzt. T2 - DGZfP-Jahrestagung 2011 CY - Bremen, Germany DA - 30.05.2011 KW - Human factors KW - ZfP KW - Ultraschallprüfung KW - UT KW - Zeitdruck PY - 2011 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-251610 UR - http://jt2011.dgzfp.de/Portals/jt2011/BB/mi2c3.pdf SN - 978-3-940283-33-7 IS - DGZfP-BB 127 (Mi.2.C.3) SP - 1 EP - 9 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) CY - Berlin AN - OPUS4-25161 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bertovic, Marija A1 - Gaal, Mate A1 - Müller, Christina A1 - Fahlbruch, B. T1 - Investigating human factors in manual ultrasonic testing: testing the human factors model N2 - The human factors approach relies on understanding the properties of human capability and limitations under various conditions and the application of that knowledge in designing and developing safe systems. Following the principles of the MTO (Man Technology Organisation) approach, emphasis should be given to the way people interact with technical as well as organisational systems. A model describing human factor influences in relation to the performance shaping factors and their effect on manual ultrasonic inspection performance had been built and a part of it empirically tested. The experimental task involved repeated inspection of 18 defects according to the standard procedure under no, middle and high time pressure. Stress coping strategies, the mental workload of the task, stress reaction and organisational factors have been measured. The results have shown that time pressure, mental workload and experience influence the quality of the inspection performance. Organisational factors and their influence on the inspection results were rated as important by the operators. However, further research is necessary into the effects of stress. KW - Human factors KW - Manual ultrasonic testing KW - In-service inspection KW - Nuclear power plants KW - Time pressure PY - 2011 DO - https://doi.org/10.1784/insi.2011.53.12.673 SN - 0007-1137 VL - 53 IS - 12 SP - 673 EP - 676 PB - British Institute of Non-Destructive Testing CY - Northampton AN - OPUS4-26083 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 - Gaal, Mate A1 - Döring, Joachim A1 - Bovtun, V. A1 - Brekow, Gerhard A1 - Kreutzbruck, Marc T1 - Charakterisierung der Luftultraschallwandler aus zellulärem ferroelektrischem Polypropylen T2 - DGZfP-Jahrestagung CY - Bremen, Germany DA - 2011-05-30 PY - 2011 AN - OPUS4-23908 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gaal, Mate A1 - Döring, Joachim A1 - Bovtun, Viktor Petrovic A1 - Brekow, Gerhard A1 - Kreutzbruck, Marc T1 - Charakterisierung der Wandler für Luftultraschallprüfung aus zellulärem Polypropylen-Ferroelektret T2 - 37th Annual Conference on Acoustics - DAGA 2011 CY - Düsseldorf, Germany DA - 2011-03-21 PY - 2011 AN - OPUS4-23496 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bertovic, Marija A1 - Fahlbruch, B. A1 - Müller, Christina A1 - Pitkänen, J. A1 - Ronneteg, U. A1 - Gaal, Mate A1 - Kanzler, Daniel A1 - Ewert, Uwe A1 - Schombach, D. T1 - Human factors approach to the acquisition and evaluation of NDT data N2 - This paper gives an introduction to the field of human factors with the focus on their influence on the reliability of NDT in the nuclear energy production (in-service inspections) and final storage of highly radioactive nuclear waste. A set of methodological tools has been developed in the scope of three projects, namely: 1) a theoretical model describing potential human factors influencing manual ultrasonic inspection performance during inservice inspections in nuclear power plants; 2) a method for identifying potential human errors during acquisition and evaluation of data gathered with mechanized ultrasonic, radiographic and eddy-current systems, as well as visual testing with a remote camera (Failure Modes and Effects Analysis, FMEA); and 3) use of eye tracking methodology to optimize existing procedures and practices. The experimental results have shown that time pressure, mental workload and experience influence the quality of the inspection performance. Noticeable were influences from the organization of the working schedule, communication, procedures, supervision and demonstration task. Implementing human redundancy in critical tasks, such as defect identification, as well as using an automated aid (software) to help operators in decision making about the existence and size of defects, could lead to other kinds of problems, namely social loafing (excerpting less effort when working on tasks collectively as compared to working alone) and automation bias (uncritical reliance on the proper function of an automated system without recognizing its limitations and the possibilities of automation failure) that might affect the reliability of NDT in an undesired manner. T2 - 18th WCNDT - World conference on nondestructive testing CY - Durban, South Africa DA - 16.04.2012 KW - Human Factors KW - Time Pressure KW - 4-Eye Principle KW - Automation Bias KW - Nuclear Waste Storage KW - In-Service Inspection (ISI) KW - Nuclear Power Plants KW - Eye Tracking KW - Failure Modes and Effects Analysis (FMEA) PY - 2012 SN - 978-0-620-52872-6 SP - 1 EP - 10 (Paper 198) AN - OPUS4-27583 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gaal, Mate A1 - Döring, Joachim A1 - Bartusch, Jürgen A1 - Lange, Thorid A1 - Hillger, W. A1 - Brekow, Gerhard A1 - Kreutzbruck, Marc T1 - Ferroelectret transducers for air-coupled ultrasonic testing of fiber-reinforced polymers T2 - QNDE-Review of Progress in Quantitative Nondestructive Evaluation, 2012 CY - Denver, CO, USA DA - 2012-07-15 PY - 2012 AN - OPUS4-26758 LA - deu 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 - CONF A1 - Gaal, Mate A1 - Bovtun, V. A1 - Kreutzbruck, Marc A1 - Stark, Wolfgang A1 - Erhard, Anton A1 - Yakymenko, Y. T1 - Visco- and linear elastic behaviour of polyproylene-based ferroelectret films T2 - Frontiers in Polymere Sciene 2013 CY - Sitges, Spain DA - 2013-05-21 PY - 2013 AN - OPUS4-28686 LA - deu 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 - CONF A1 - Gaal, Mate A1 - Bartusch, Jürgen A1 - Daschewski, Maxim A1 - Dohse, Elmar A1 - Köppe, Enrico A1 - Weise, Matthias A1 - Hillger, W. A1 - Kreutzbruck, Marc T1 - Schwingverhalten des Ferroelektret-Senders für Luftultraschall T2 - DGZfP-Jahrestagung 2013 CY - Dresden, Germany DA - 2013-05-06 KW - Luftultraschall KW - Wandler KW - Ferroelektret KW - Zelluläres Polypropylen KW - Elektrostriktion PY - 2013 SN - 978-3-940283-49-8 IS - Mo.3.B.4 SP - 1 EP - 8 AN - OPUS4-28651 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gaal, Mate A1 - Bartusch, Jürgen A1 - Daschewski, Maxim A1 - Dohse, Elmar A1 - Köppe, Enrico A1 - Weise, Matthias A1 - Kreutzbruck, Marc A1 - Hillger, W. T1 - Schwingverhalten des Ferroelektret-Senders für Luftultraschall T2 - DGZfP-Jahrestagung 2013 CY - Dresden, Germany DA - 2013-05-06 PY - 2013 AN - OPUS4-28618 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gaal, Mate A1 - Döring, Joachim A1 - Bartusch, Jürgen A1 - Lange, Thorid A1 - Hillger, W. A1 - Brekow, Gerhard A1 - Kreutzbruck, Marc T1 - Ferroelectret transducers for air-coupled ultrasonic testing of fiber-reinforced polymers N2 - Ferroelectrets are promising materials for air-coupled ultrasonic transducers. A transducer made of polarized cellular polypropylene, including its electronic interface, was developed and compared with conventional air-coupled probes. Test pieces of fiber-reinforced polymer containing impact flaws and flat-bottom holes were inspected in transmission. The ferroelectret transducers achieved a considerably higher signal-to-noise ratio. The impacts were clearly visible with all transducers, but less noisy with ferroelectret transducers. The flat-bottom holes were better detectable than with a conventional probe with about the same focus size. T2 - 39th Annual review of progress in quantitative nondestructive evaluation CY - Denver, Colorado, USA DA - 2012-07-15 KW - Air-coupled ultrasound KW - Transducer KW - Ferroelectret PY - 2013 SN - 978-0-7354-1129-6 DO - https://doi.org/10.1063/1.4789224 SN - 0094-243X SN - 1551-7616 N1 - Serientitel: AIP conference proceedings – Series title: AIP conference proceedings VL - 1511 SP - 1534 EP - 1540 AN - OPUS4-27747 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Döring, Joachim A1 - Bartusch, Jürgen A1 - Gaal, Mate A1 - Kreutzbruck, Marc A1 - Erhard, Anton A1 - Bovtun, Viktor Petrovic T1 - Ferroelektret-Prüfköpfe für die zerstörungsfreie Prüfung mit Luftultraschall N2 - Für die luftgekoppelte Ultraschall-Prüfung wird der Prototyp eines neuartigen Prüfkopfes vorgestellt. Statt eines piezokeramischen Ultraschall-Wandlers mit einer λ/4-Anpassschicht wird eine Ferroelektret-Folie aus schaumförmigem Polypropylen eingesetzt. Durch die außerordentlich geringe akustische Impedanz der Folie reduzieren sich die Reflexionsverluste an den Grenzschichten zur Luft so stark, dass bei diesem Prüfkopf auf eine λ/4-Anpassschicht verzichtet werden kann. Außerdem ist die Folie hochspannungsfest. Sie konnte mit Spannungen von mehr als 3500 V angesteuert werden und erlaubte eine Vorspannung am Ultraschall-Wandler des Empfangsprüfkopfes von 2000 V. Mithilfe der hohen Anregungsspannung stieg die Amplitude des akustischen Prüfimpulses auf das 11,2-Fache. Die Empfindlichkeit des Empfängers erhöhte sich durch die Vorspannung weiter um den Faktor 4,3. Insgesamt steigt die Amplitude am Empfänger also auf das 48-Fache, bei gleichbleibendem Rauschpegel. Ein abschließender Vergleich mit kommerziellen Luftultraschall-Prüfköpfen belegt die Überlegenheit der Folien-Prüfköpfe. Damit rückt der Einsatz einer vollwertigen Impuls-Echo-Technik auch bei der luftgekoppelten Ultraschallprüfung deutlich näher. KW - Prüfkopf KW - Ferroelektret KW - Luftultraschall KW - Zerstörungsfreie Prüfung PY - 2013 SN - 0025-5300 VL - 55 IS - 2 SP - 96 EP - 102 PB - Hanser CY - München AN - OPUS4-27778 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gaal, Mate A1 - Bartusch, Jürgen A1 - Dohse, Elmar A1 - Kreutzbruck, Marc A1 - Amos, J. M. T1 - Air-coupled ultrasonic testing of metal adhesively bonded joints using cellular polypropylene transducers T2 - QNDE - Review of Prgress in Quantitative Nondestructive Evaluation CY - Baltimore, MD, USA DA - 2013-07-21 PY - 2013 AN - OPUS4-29059 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc A1 - Pelkner, Matthias A1 - Gaal, Mate A1 - Daschewski, Maxim A1 - Brackrock, Daniel T1 - Evolution of modern NDT-methods for the inspection of lightweight components N2 - NDT is a multidisciplinary research area fusing the disciplines of natural Science and engineering. Particularly in the early development stages of a new testing method, feasibility investigations focus on the fundamental physical interaction between the sensing mechanism and specimen. Research activities during subsequent phases of modular prototype development, technical System Integration and Validation primarily attempt to solve the practical engineering and real-life aspects of a testing method. We show several examples of new methods in different stages of development and highlight the potential for further industrial use. The first section deals with Steel surfaces of lightweight components which are inspected with pm-sized magneto resistive sensor arrays. This quantitative magnetic stray field approach combines high spatial resolution and very high sensitivity, enabling the user to detect even very small micro-defects. Tuming to CFRP components we also show new developments in airbome ultrasonic testing. Here we use ferroelectret foils to reduce the acoustical mismatch between transducer and air, which enhances the signal-to-noise ratio. A further example illuminates the use of metallic nano layers as a broadband thermo acoustical emitter. Their use provides both high sound pressures and very broadband Signal characteristics. When it comes to CFRP components and other anisotropic and highly Scattering materials, ultrasonic matrix arrays in conjunction with many angles of incidences per transducer position can help to enhance the statistics of a testing problem. In the field of conventional water-coupled UT testing we also show the use of matrix array transducers providing a tomographic-like 3D-image of impact damage in CFRP samples. T2 - 12th International conference of the Slovenian society for non-destructive testing - Application of contemporary non-destructive testing in engineering CY - Portoroz, Slovenia DA - 04.09.2013 KW - GMR-sensors arrays KW - Air coupled ultrasonics KW - Thermo acoustical transducers KW - Matrix arrays PY - 2013 SN - 978-961-93537-0-7 SP - 303 EP - 314 AN - OPUS4-29245 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gaal, Mate A1 - Bartusch, Jürgen A1 - Döring, Joachim A1 - Dohse, Elmar A1 - Lange, Thorid A1 - Hillger, W. A1 - Kreutzbruck, Marc T1 - Air-coupled ferroelectret ultrasonic transducers applied to testing of fiber-reinforced polymers T2 - 12th International conference of the Slovenian society for non-destructive testing - Application of contemporary non-destructive testing in engineering CY - Portoroz, Slovenia DA - 2013-09-04 KW - Air-coupled ultrasound KW - Transducer KW - Ferroelectret KW - Cellular polypropylene KW - Fiber-reinforced polymers PY - 2013 SN - 978-961-93537-0-7 SP - 43 EP - 50 AN - OPUS4-29927 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gaal, Mate A1 - Bartusch, Jürgen A1 - Dohse, Elmar A1 - Kreutzbruck, Marc A1 - Amos, J. M. ED - Chimenti, D.E. ED - Bond, L.J. ED - Thompson, D.O. T1 - Air-coupled ultrasonic testing of metal adhesively bonded joints using cellular polypropylene transducers N2 - Adhesively bonded aluminum components have been widely used in the aerospace industry for weight-efficient and damage-tolerant structures. Automated squirter jet immersion ultrasonic testing is a common inspection technique to assure the bond integrity of large, contoured assemblies. However, squirter jet inspection presents several limitations in scanning speed, related to water splash noise over protruding stiffeners and splash interference crosstalk in multi-channel inspection systems. Air-coupled ultrasonic testing has been evaluated as an alternative, possibly offering the benefits of increased throughput by enabling higher speeds, and eliminating the contamination concerns and maintenance issues of water couplant systems. Adhesive joints of multi-layer aluminum plates with artificial disbonds were inspected with novel air-coupled ultrasonic probes based on cellular polypropylene. Disbonds of various sizes were engineered in several multi-layer configurations and at various depths. Results were compared with squirter jet immersion and conventional piezoelectric transducer designs in terms of scan contrast, resolution and inspection time. T2 - 40th Annual review of progress in quantitative nondestructive evaluation CY - Baltimore, Maryland, USA DA - 21.07.2013 KW - Air-coupled KW - Ultrasonic KW - Metal bond KW - Ferroelectret PY - 2014 SN - 978-0-7354-1212-5 SN - 978-0-7354-1211-8 DO - https://doi.org/10.1063/1.4864857 SN - 0094-243X N1 - Serientitel: AIP conference proceedings – Series title: AIP conference proceedings VL - 1581 33A SP - 471 EP - 478 PB - AIP Publishing AN - OPUS4-31362 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gaal, Mate A1 - Bovtun, V. A1 - Stark, Wolfgang A1 - Kreutzbruck, Marc ED - Kollmeier, B. T1 - Bestimmung der elastischen Eigenschaften des Polypropylen-Ferroelektrets N2 - Ferroelektrete sind zelluläre polarisierte Polymere, die ferroelektrische und dadurch auch piezoelektrische Eigenschaften aufweisen. Unter anderem werden sie für den Bau von Mikrofonen und Ultraschallwandlern für Materialprüfung eingesetzt. Dabei erweist sich ihre besonders niedrige akustische Impedanz als Vorteil. Ursache dafür ist vor allem ihr außergewöhnlich niedriger Elastizitätsmodul in Dickenrichtung. In diesem Beitrag werden zwei Methoden für die Ermittlung des Elastizitätsmoduls des geladenen zellulären Polypropylens (zPP) dargestellt. Die erste ist eine neuartige modellgestützte Methode mittels Laservibrometrie an dem eigenentwickelten Polypropylen-Wandler, wobei die Resonanzschwingung des Wandlers bei 250 kHz gemessen wird. Die zweite Methode ist dynamisch-mechanische Analyse (DMA) durchgeführt mit Frequenzen von 0,3 bis 50 Hz, erstmalig für das zPP angewendet. T2 - DAGA 2014 - 40. Jahrestagung für Akustik CY - Oldenburg, Germany DA - 10.03.2014 PY - 2014 SN - 978-3-939296-06-5 SP - 1 EP - 2 AN - OPUS4-31368 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gaal, Mate A1 - Stegemann, Robert A1 - Pelkner, Matthias A1 - Kreutzbruck, Marc T1 - Luftultraschallprüfung von CFK mit planaren und fokussierenden Wandlern T2 - DACH-Jahrestagung 2014 CY - Salzburg, Austria DA - 2014-07-20 PY - 2014 AN - OPUS4-31618 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gaal, Mate A1 - Dohse, Elmar A1 - Bartusch, Jürgen A1 - Köppe, Enrico A1 - Kreutzbruck, Marc A1 - Hillger, W. A1 - Amos, J. M. T1 - Ultrasonic testing of adhesively bonded joints using air-coupled cellular polypropylene transducers N2 - In air-coupled ultrasonic testing, the impedance mismatch between the transducer and the air is commonly being solved by adding matching layers to composite transducers. To avoid the difficult technological procedure regarding matching layers, some new piezoelectric materials have been proposed. Most promising are ferroelectrets, which are charged cellular polymers, having ferroelectric and consequently piezoelectric properties. In particular, the extreme softness of cellular polypropylene (cPP) leads to a high piezoelectric constant and to a good impedance match with the air, making matching layers redundant. Its elasticity modulus below 1 MPa causes an additional effect not observed with common piezoelectric materials: that is the electrostrictive effect, here defined as the thickness change due to the attractive force between the transducer electrodes. This effect exceeds the piezoelectric effect at excitation voltages over 1 kV. The extreme softness of cPP leads also to high flexibility, enabling easy focusing by bending the transducer. We have developed air-coupled ultrasonic transducers based on cPP. This includes the electrical matching networks for the transmitter and for the receiver. The transmitter is excited with voltages up to 2.5 kV, so that the electrostrictive effect dominates, leading to sound pressure around 145dB at the transducer surface. These transducers have been applied for testing carbon-fiber-reinforced polymer plates, adhesive joints and other composite structures. Here we report about ultrasonic transmission of two types of adhesive joints. The first one is multi-layer aluminium components with some artificial disbonds, which are common in aerospace industry, and the second one is an aluminium-steel joint with polyurethane adhesive, which is used in automotive industry. T2 - ECNDT 2014 - 11th European conference on non-destructive testing CY - Prague, Czech Republic DA - 06.10.2014 KW - Air-coupled KW - Ultrasonic testing KW - Ferroelectret KW - Cellular polypropylene KW - Transducer KW - Adhesive joint PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-317204 SN - 978-80-214-5018-9 SP - 1 EP - 8 PB - Brno University of Technology AN - OPUS4-31720 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gaal, Mate A1 - Dohse, Elmar A1 - Bartusch, Jürgen A1 - Köppe, Enrico A1 - Kreutzbruck, Marc A1 - Amos, J. M. A1 - Hillger, W. T1 - Ultrasonic Testing of Adhesively Bonded Joints Using Air-Coupled Cellular Polypropylene Transducer T2 - 11th European Conference on Non-Destructive Testing (ECNDT) CY - Prag, Tschechien DA - 2014-10-06 PY - 2014 AN - OPUS4-33227 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gaal, Mate A1 - Dohse, Elmar A1 - Bartusch, Jürgen A1 - Kreutzbruck, Marc T1 - Ultraschallprüfköpfe zur Ankopplung über Luft auf der Basis von Ferroelektreten T2 - Workshop "Innovative ZfP mit bildgebender Ultraschallprüftechnik" CY - Braunschweig, Germany DA - 2014-03-14 PY - 2014 AN - OPUS4-30426 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gaal, Mate A1 - Stark, Wolfgang A1 - Kreutzbruck, Marc A1 - Bovtun, V. T1 - Bestimmung der elastischen Eigenschaften des Polypropylen-Ferroelektrets T2 - DAGA 2014, 40. Jahrestagung für Akustik CY - Oldenburg, Germany DA - 2014-03-10 PY - 2014 AN - OPUS4-30427 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -