TY - JOUR A1 - Schukar, Vivien A1 - Kusche, Nadine A1 - Kalinka, Gerhard A1 - Habel, Wolfgang T1 - Field deployable fiber bragg grating strain patch for long-term stable health monitoring applications N2 - A fiber Bragg grating (FBG) strain patch specially adapted for long-term and high-strain applications has been developed and characterized. The design concept for the patch is based on a glass-fiber reinforced plastic (gfrp) carrier material. The developed concept for the FBG integration into the carrier material was derived from reliable integration procedure of FBG sensors into composite structures. The patches' temperature sensitivity, strain gauge factor, fiber–matrix interface adhesion and fatigue behavior were characterized. As a result, FBG strain patches with linear temperature and strain behavior, as well as excellent fatigue resistance, were developed and can be used as part of a monitoring system for advanced composite materials in aerospace structures or wind turbine power plants. KW - Fiber Bragg grating KW - Patch KW - Strain gauge factor KW - Temperature sensitivity KW - Push-out test KW - Validation KW - Fatigue behavior PY - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-276271 SN - 2076-3417 VL - 3 IS - 1 SP - 39 EP - 54 PB - MDPI CY - Basel AN - OPUS4-27627 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schukar, Vivien A1 - Kadoke, Daniel A1 - Kusche, Nadine A1 - Münzenberger, Sven A1 - Gründer, Klaus-Peter A1 - Habel, Wolfgang T1 - Validation and qualification of surface-applied fibre optic strain sensors using application-independent optical techniques N2 - Surface-applied fibre optic strain sensors were investigated using a unique validation facility equipped with application-independent optical reference systems. First, different adhesives for the sensor's application were analysed regarding their material properties. Measurements resulting from conventional measurement techniques, such as thermo-mechanical analysis and dynamic mechanical analysis, were compared with measurements resulting from digital image correlation, which has the advantage of being a non-contact technique. Second, fibre optic strain sensors were applied to test specimens with the selected adhesives. Their strain-transfer mechanism was analysed in comparison with conventional strain gauges. Relative movements between the applied sensor and the test specimen were visualized easily using optical reference methods, digital image correlation and electronic speckle pattern interferometry. Conventional strain gauges showed limited opportunities for an objective strain-transfer analysis because they are also affected by application conditions. KW - Fiber Bragg grating KW - Surface application KW - Qualification KW - Strain transfer KW - Digital image correlation KW - Electronic speckle pattern interferometry PY - 2012 U6 - https://doi.org/10.1088/0957-0233/23/8/085601 SN - 0957-0233 SN - 1361-6501 VL - 23 IS - 8 SP - 085601-1 - 085601-9 PB - IOP Publ. Ltd. CY - Bristol AN - OPUS4-26639 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schukar, Vivien A1 - Kusche, Nadine A1 - Habel, Wolfgang T1 - How reliably do fiber Bragg grating patches perform as strain sensors? N2 - In Germany, the first guideline for the use of fiber Bragg grating strain sensors, 'Optical Strain Sensor based on Fiber Bragg Grating' (Berlin, Germany: Beuth-Verlag, 2010), has been developed by the GESA guideline group of VDI, 'The Association of German Engineers' and published by Beuth-Verlag. This guideline provides the basic specifications of this sensor type and the sensor characteristics, which have to be known for a reliable sensor performance. In conformity to this guideline, experimental investigations on the strain transfer characteristics of fiber Bragg grating patches have been carried out. A comparison between patches and resistance strain gauges during tensile tests and combined temperature and tensile loading was carried out. The evaluated strain gauge factor and the temperature sensitivity of the strain gauge factor have been compared to the manufacturer's data. The overall performance of the patches has been evaluated. The experimental investigations showed that there are considerable disagreements between the manufacturer's specifications and the observed characteristics. KW - Fiber Bragg grating KW - Strain gauge KW - Strain transfer KW - Validation PY - 2012 U6 - https://doi.org/10.1109/JSEN.2011.2139202 SN - 1530-437X SN - 1558-1748 VL - 12 IS - 1 SP - 128 EP - 132 CY - New York, NY, USA AN - OPUS4-25486 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -