TY - JOUR A1 - Schlichting, Joachim A1 - Maierhofer, Christiane A1 - Kreutzbruck, Marc T1 - Defect sizing by local excitation thermography T2 - QIRT Journal N2 - In this article, we present a measurement procedure to gain information about depth and angle of surface braking 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 for heating and 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. Using FEM simulation we can show herein that it is possible to simultaneously resolve the angle and depth and, in particular, the depth of non-perpendicular cracks. PB - Lavoisier CY - Cachan Cedex KW - Surface braking cracks KW - Crack sizing KW - FEM KW - Laser thermography PY - 2011 UR - https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/24254 AN - OPUS4-24254 SN - 1768-6733 VL - 8 IS - 1 SP - 51 EP - 63 AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany