TY - JOUR A1 - Pavlovic, Mato A1 - Zoëga, Andreas A1 - Kurz, J. H. A1 - Zanotelli, Christina T1 - Investigations to introduce the probability of detection method for ultrasonic inspection of hollow axles at Deutsche Bahn N2 - The vast experience with the automated, ultrasonic system for the inspection of hollow railway axles used by Deutsche Bahn shows that much smaller flaws are detectable than required. This results in a number of false calls. False calls lead to unnecessary demounting and disassembling of wheelsets, which generates unnecessary additional costs. In order to adjust the sensitivity of the inspection system to reduce the number of false calls without compromising safety, the capability of the system to detect cracks needs to be comprehensively established. This capability can be quantified by using probability of detection (POD) curves for the system. The multi-parameter POD model makes it possible to include several factors that influence the crack detection in the analysis. The analysis presented in this paper shows that crack position, orientation, depth extension, and shape as well as the geometry of the axle all have influence on the ultrasonic response amplitude. For future work, calculation of the POD using multi-parameter POD model with these parameters is planned. T2 - ESIS TC24 Workshop "Integrity of Railway Structures" CY - Leoben, Austria DA - 24.10.2016 KW - Crack KW - Reliability KW - POD KW - Axle KW - Ultrasonic PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-415201 DO - https://doi.org/10.1016/j.prostr.2017.07.002 SN - 2452-3216 VL - 4 SP - 79 EP - 86 PB - Elsevier, B.V. AN - OPUS4-41520 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zoëga, Andreas T1 - Spannungsabhängigkeit elastischer Wellen in Beton KW - Beton KW - Spannungsabhängigkeit KW - Schallgeschwindigkeit KW - Oberflächenwellen KW - Richtungsabhängigkeit PY - 2013 SN - 0005-9900 SN - 1437-1006 VL - 108 IS - 7 SP - 508 EP - 510 PB - Ernst CY - Berlin AN - OPUS4-30905 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Shokouhi, Parisa A1 - Zoëga, Andreas A1 - Wiggenhauser, Herbert A1 - Fischer, G. T1 - Surface wave velocity-stress relationship in uniaxially loaded concrete N2 - The sonic surface wave (or Rayleigh wave) velocity measured on prismatic concrete specimens under uniaxial compression was found to be highly stress-dependent. At low stress levels, the acoustoelastic effect and the closure of existing microcracks results in a gradual increase in surface wave velocities. At higher stress levels, concrete suffers irrecoverable damage: the existing microcracks widen and coalesce and new microcracks form. This progressive damage process leads first to the flattening and eventually the drop in the velocity-stress curves. Measurements on specimens undergoing several loading cycles revealed that the velocities show a stress-memory effect in good agreement with the Kaiser effect. Comparing the velocities measured during loading and unloading, the effects of stress and damage on the measured velocities could be differentiated. Moreover, the stress dependency of surface wave velocity proved to be direction-dependent. The velocity increases and decreases the most when measured parallel and perpendicular to the loading axis, respectively. KW - Acoustic emission KW - Acoustoelasticity KW - Microcracking KW - Surface waves KW - Velocity measurement PY - 2012 SN - 0889-325x VL - 109 IS - 2 SP - 141 EP - 148 PB - ACI CY - Farmington, Mich., USA AN - OPUS4-27999 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zoëga, Andreas A1 - Stoppel, Markus T1 - Automatisierte Multisensorsysteme zur Zustandsbewertung T2 - Fachtagung Bauwerksdiagnose 2012, Praktische Anwendungen Zerstörungsfreier Prüfungen und Zukunftsaufgaben CY - Berlin, Germany DA - 2012-02-23 PY - 2012 AN - OPUS4-25855 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zoëga, Andreas A1 - Stoppel, Markus A1 - Feldmann, Rüdiger T1 - Automatisierte Multisensorsysteme zur Zustandsbewertung N2 - Zerstörungsfreie Prüfverfahren sind ein zuverlässiges Hilfsmittel für die Zustandsermittlung von Bauwerken. In vielen Veröffentlichungen konnten die Vorteile von flächigen Messungen verbunden mit einer dreidimensionalen Auswertung gezeigt werden. In diesem Artikel soll auf die Automatisierung von Multisensorsystemen für zeit- und personaleffiziente flächige Messungen eingegangen werden. Zwei Systeme mit unterschiedlichen Automatisierungsansätzen und den daraus resultierenden verschiedenartigen Verwendungsmöglichkeiten sollen für einen wirtschaftlichen Einsatz unter den Aspekten der Flexibilität, des Zeitaufwandes und der zu erzielenden Messleistung vorgestellt werden. T2 - Fachtagung Bauwerksdiagnose 2012 - Praktische Anwendungen zerstörungsfreier Prüfungen und Zukunftsaufgaben CY - Berlin, Deutschland DA - 23.02.2012 KW - Bauwesen KW - Zerstörungsfreie Prüfung KW - Automatisierung KW - Multisensorsysteme / BetoScan / ZFP-Scanner PY - 2012 SN - 978-3-940283-40-5 IS - DGZfP-BB 134 (Vortrag 07) SP - 1 EP - 9 CY - Berlin AN - OPUS4-25548 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krause, Martin A1 - Milmann, Boris A1 - Feldmann, Rüdiger A1 - Friese, Martin A1 - Wöstmann, Jens A1 - Zoëga, Andreas A1 - Sodeikat, C. T1 - Thickness measurement & quality assurance of floor slabs & diaphragm walls T2 - Structural faults & repair 2010 - International conference and exhibition CY - Edinburgh, Scotland, UK DA - 2010-06-15 KW - Ultrasonic echo KW - Radar KW - Impact-echo KW - Synthetic aperture focusing technique (SAFT) KW - Compaction faults PY - 2010 SN - 0-947644-67-9 SP - 1 EP - 9 PB - Engineering Technics Press CY - Edinburgh, Scotland AN - OPUS4-22897 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Shokouhi, Parisa A1 - Zoëga, Andreas A1 - Wiggenhauser, Herbert ED - Thompson, D.O. ED - Chimenti, D.E. T1 - Nondestructive evaluation of damage in concrete under uniaxial compression N2 - Surface wave velocities over the sonic frequency range (<20 KHz) were measured on concrete specimens undergoing various cycles of loading and unloading. Acoustic Emission test (AE) was conducted simultaneously to monitor the microcracking activities. The sonic surface wave velocity was found to be highly stress-dependent. The observed changes in surface wavespeed are repeatable and follow a particular trend. By measuring the wave velocities in both loading and unloading phases, the effects of stress and stress-induced damages could be distinguished. The observed trend could be explained by a combination of acoustoelasticity and microcracking theories. T2 - 36th Annual Review of Progress in Quantitative Nondestructive Evaluation CY - Kingston, RI, USA DA - 2009-07-26 KW - Nondestructive testing (NDT) KW - Microcracking KW - Sonic wave velocity KW - Concrete KW - Load KW - Stress PY - 2010 UR - http://link.aip.org/link/?APCPCS/1211/1525/1 SN - 978-0-7354-0748-0 SN - 0743-0760 SN - 0094-243X N1 - Serientitel: AIP conference proceedings – Series title: AIP conference proceedings SP - 1525 EP - 1532 CY - Melville, NY AN - OPUS4-22642 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Shokouhi, Parisa A1 - Zoëga, Andreas A1 - Wiggenhauser, Herbert T1 - Nondestructive investigation of stress-induced damage in concrete N2 - The changes in the sonic surface wave velocity of concrete under stress were investigated in this paper. Surface wave velocities at sonic frequency range were measured on a prismatic concrete specimen undergoing several cycles of uniaxial compression. The loading was applied (or removed) gradually in predefined small steps (stress-controlled). The surface wave velocity was measured at every load step during both loading and unloading phases. Acoustic Emission (AE) test was conducted simultaneously to monitor the microcracking activities at different levels of loading. It was found that the sonic surface wave velocity is highly stress dependent and the velocity-stress relationship follows a particular trend. The observed trend could be explained by a combination of acoustoelasticity and microcracking theories, each valid over a certain range of applied stresses. Having measured the velocities while unloading, when the material suffers no further damage, the effect of stress and damage could be differentiated. The slope of the velocity-stress curves over the elastic region was calculated for different load cycles. This quantity was normalized to yield a dimensionless nonlinear parameter. This parameter generally increases with the level of induced damage in concrete. KW - Nondestructive testing (NDT) KW - Surface wave velocity KW - Concrete KW - Acoustoelasticity KW - Microcracking PY - 2010 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-215943 UR - http://downloads.hindawi.com/journals/ace/2010/740189.pdf DO - https://doi.org/10.1155/2010/740189 SN - 1687-8094 SN - 1687-8086 VL - 2010 IS - Article ID 740189 SP - 1 EP - 9 PB - Hindawi Publ. Corp. CY - New York, NY, USA AN - OPUS4-21594 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Shokouhi, Parisa A1 - Niederleithinger, Ernst A1 - Zoëga, Andreas A1 - Barner, Andreas A1 - Schöne, Dieter T1 - Using ultrasonic coda wave interferometry for monitoring stress-induced changes in concrete T2 - 23rd SAGEEP Symposium on the application of geophysics to engineering and environmental problems CY - Keystone, Colorado, USA DA - 2010-04-11 KW - Coda wave interferometry KW - Concrete KW - Beton KW - Stress KW - Ultrasonics KW - Ultraschall PY - 2010 SN - 1554-8015 SP - 650 EP - 654 AN - OPUS4-21570 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Friese, Martin A1 - Taffe, Alexander A1 - Wöstmann, Jens A1 - Zoëga, Andreas T1 - Zerstörungsfreie Untersuchungen am Brückenbauwerk A1 Hagen/Schwerte KW - Ultraschallecho KW - Impakt-Echo KW - Radar KW - Zerstörungsfreie Prüfung KW - Brücke KW - Hagen KW - Scannende Systeme KW - Spannglied KW - Bildgebende Darstellung PY - 2009 SN - 0943-9307 IS - B 65 SP - 1 EP - 52 PB - Wirtschaftsverlag NW - Verlag für neue Wissenschaft GmbH CY - Bremerhaven AN - OPUS4-20958 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -