TY - CONF A1 - Schlichting, Joachim T1 - Geometrische Charakterisierung von Fehlstellen lokal angeregter aktiver Thermografie T2 - 15. ITG-/GMA-Fachtagung "Sensoren und Messsysteme 2010" CY - Nuremberg, Germany DA - 2010-05-18 PY - 2010 AN - OPUS4-21753 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schlichting, Joachim T1 - Geometrische Charakterisierung von Fehlstellen mittels lokal angeregter aktiver Thermografie T2 - DGZfP-Jahrestagung 2010 CY - Erfurt, Germany DA - 2010-05-10 PY - 2010 AN - OPUS4-21760 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kervalishvili, Guram N. A1 - Schlichting, Joachim A1 - Maierhofer, Christiane A1 - Kreutzbruck, Marc T1 - Heat transfer modeling of local thermal excitation for surface crack detection and characterization N2 - In the presented paper the use of local excitation (laser beam) for crack detection and characterization is simulated. As we could see, using the temperature differences between two reference points was large enough to detect and characterize the crack, even for such small value of laser power as 2 W. The influence of radiation and convection on the temperature difference was negligible (about 0.1%). The influence of heat conduction, in case of crack with air, was very small (about 3%). The main mechanism which influences the temperature differences between the reference points is the heat conduction in steel. From the presented results one can see that temperature differences are increasing with an increase of the crack depth or the crack length. Better resolution and characterization of the crack depths and lengths should be achieved with increased duration of heating time or the laser power. We could also see that the best position for the laser spot to characterize the crack is the closest one. Also, comparison of 2D and 3D simulation results for circular heat source used as local excitation mechanism had showed that only full 3D modelling will allow accomplishing a quantitative level of comparison between experimental and simulation results. T2 - ECNDT 2010 - 10th European conference on non-destructive testing CY - Moscow, Russia DA - 2010-06-07 KW - Thermography KW - Heat transfer modeling KW - Surface crack PY - 2010 SN - 978-1-617-82791-4 SP - 1 EP - 10 AN - OPUS4-22973 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Maierhofer, Christiane A1 - Röllig, Mathias A1 - Schlichting, Joachim ED - Maierhofer, C. ED - Reinhardt, H.-W. ED - Dobmann, G. T1 - Active thermography for evaluation of reinforced concrete structures KW - Active thermography KW - Pulse-phase thermography KW - Emissivity KW - Reinforced concrete KW - Subsurface defects PY - 2010 SN - 978-1-84569-950-5 VL - 2 IS - Chapter 17 SP - 370 EP - 402 PB - Woodhead Publ. AN - OPUS4-22611 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schlichting, Joachim A1 - Kervalishvili, Guram N. A1 - Maierhofer, Christiane A1 - Kreutzbruck, Marc T1 - Geometrische Charakterisierung von Fehlstellen mittels lokal angeregter aktiver Thermografie N2 - In diesem Beitrag wird eine Methode zur Charakterisierung von offenen Oberflächenrissen mittels aktiver Thermografie präsentiert. Hierzu wird die Probe ortsfest lokal mit einem Laser erwärmt und die resultierende Oberflächentemperatur mittels Infrarotkamera aufgenommen. Bei einer ungestörten Probe ergibt sich ein rotationssymmetrisches Temperaturprofil. Betrachtet man hingegen einen Bereich mit einem Oberflächenriss, so kommt es durch die Störung des lateralen Wärmetransports zu einer unsymmetrischen Temperaturverteilung. Durch die quantitative Analyse diese Unsymmetrie lassen sich Aussagen über geometrische Parameter des Risses treffen. T2 - DGZfP-Jahrestagung 2010 CY - Erfurt, Deutschland DA - 2010-05-10 PY - 2010 SN - 978-3-940283-26-9 IS - DGZfP-BB 122 (Mi.1.C.2) SP - 1 EP - 8 CY - Berlin AN - OPUS4-21869 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schlichting, Joachim A1 - Kervalishvili, Guram N. A1 - Maierhofer, Christiane A1 - Kreutzbruck, Marc T1 - Geometrische Charakterisierung von Fehlstellen mittels lokal angeregter aktiver Thermografie / Characterizing geometrical parameters of voids with locally excited active thermography T2 - Sensoren und Messsysteme 2010 - 15. ITG/GMA-Fachtagung CY - Nürnberg, Deutschland DA - 2010-05-18 PY - 2010 SN - 978-3-8007-3260-9 IS - Paper 120 SP - 682 EP - 687 PB - VDE Verlag GmbH CY - Berlin, Offenbach AN - OPUS4-21855 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Schlichting, Joachim A1 - Maierhofer, Christiane A1 - Kreutzbruck, Marc T1 - Defect sizing by local excitation thermography N2 - In this article, we present a measurement procedure to gain information about depth and angle of open surface cracks. The method is based on a local excitation with, e.g., a laser. The resulting surface temperature is recorded with an infrared camera. Based on this data, crack-caused anisotropies in the lateral heat flow can be detected and exploited to characterise the cracks. The experimental set-up is based on a Nd:YAG laser. The beam is focused on the test sample by using an optical scanner to generate the required lateral heat flow. The time resolved temperature distribution is recorded with a high-speed infrared camera (InSb FPA, 3 to 5 µm) providing a frame rate of up to 500 Hz. Up to now, only qualitative information was gained from measurements of this type. Whereas the local transient behaviour of temperature distribution provides also quantitative information of the crack parameters. The general concept of the method presented herein has already been published [1], but the mentioned publication is focused on the crack depth only. In this paper, we can show that it is possible to simultaneously resolve the angle and depth and, in particular, the depth of non-perpendicular cracks. T2 - QIRT 10 - 10th International conference on Quantitative InfraRed Thermography CY - Québec, Canada DA - 2010-07-27 KW - FEM KW - Risse KW - Thermografie PY - 2010 UR - http://qirt.gel.ulaval.ca/archives/qirt2010/papers/QIRT%202010-121.pdf SN - 978-2-9809199-1-6 IS - QIRT 2010-121 SP - 773 EP - 780 AN - OPUS4-21957 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schlichting, Joachim T1 - Laser Thermography for Quantitative Crack Characterization T2 - Quantitative Non-Destructive Evaluation 2010 CY - San Diego, CA, USA DA - 2010-07-18 PY - 2010 AN - OPUS4-21963 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schlichting, Joachim T1 - Defect Sizing by local Excitation Thermography T2 - Quantitative Infrared Thermography International Conference 2010 (QIRT) CY - Quebec City, Canada DA - 2010-07-27 PY - 2010 AN - OPUS4-21964 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -