TY - CONF A1 - Kusche, Nadine A1 - Schukar, Vivien A1 - Hofmann, Detlef A1 - Basedau, Frank A1 - Habel, Wolfgang A1 - Woschitz, H. A1 - Lienhart, W. ED - Jaroszewicz, L.R. T1 - Field examples for optical fibre sensor condition diagnostics based on distributed fibre-optic strain sensing N2 - Fibre optic sensors for monitoring in safety-relevant structures have to be validated in order to proof their reliability under typical structural load conditions. The reliable use of optical fibre sensors depends strongly on an appropriate and qualitative application. Diagnostics of the physical condition of embedded and surface-applied fibre optic strain sensors are demonstrated on field examples. Distributed strain measurement based on Rayleigh backscattering is used to determine breakage of the fibre, interface adhesion problems and to identify application related strain transfer mechanisms. T2 - EWOFS 2013 - 5th European workshop on optical fibre sensors CY - Kraków, Poland DA - 19.05.2013 KW - Fibre Bragg grating KW - Rayleigh backscattering KW - Condition diagnostics KW - Strain KW - Strain transfer PY - 2013 SN - 978-0-81949-634-8 U6 - https://doi.org/10.1117/12.2025567 SN - 0277-786X N1 - Serientitel: Proceedings of SPIE – Series title: Proceedings of SPIE VL - 8794 IS - Paper 8794 - 181 SP - 879433-1 EP - 879433-4 AN - OPUS4-28570 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kusche, Nadine A1 - Schukar, Vivien A1 - Schilder, Constanze A1 - Köppe, Enrico A1 - Habel, Wolfgang ED - Chang, F.-K. T1 - Development and qualification of FBG-based strain patches and rosettes N2 - A fibre Bragg grating (FBG) strain patch specially adapted for long-term and high-strain applications was developed and characterised. Additionally, in the case of unknown main stress axis, two fibre optic strain rosettes were developed. The design concept for the patch and the rosettes is based on a glass fibre reinforced plastic (gfrp) carrier material. The patches were characterised due to their strain gauge factor and fatigue behaviour. As a result, FBG strain patches with linear strain behaviour and excellent fatigue resistance were developed and can be used as part of a monitoring system for aerospace structures or wind turbine power plants. The rosettes were designed to be small in geometrical size and their strain transfer behaviour was characterised. T2 - 8th International workshop on structural health monitoring 2011 CY - Stanford, CA, USA DA - 13.09.2011 KW - Fibre Bragg grating KW - Patch KW - Rosette KW - Strain gauge factor KW - Fatigue behaviour KW - Validation PY - 2011 SN - 978-1-60595-053-2 VL - 2 SP - 1457 EP - 1465 PB - DEStech Publications, Inc. AN - OPUS4-24512 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schilder, Constanze A1 - Kusche, Nadine A1 - Schukar, Vivien A1 - Münzenberger, Sven A1 - Habel, Wolfgang T1 - Experimental qualification by extensive evaluation of fibre optic strain sensors N2 - Fibre optic strain sensors used in practical applications have to provide reliable measurements. Therefore, the applied sensor and the sensor systems must be validated experimentally. This can be achieved with facilities which use physically independent measurement systems in order to avoid the influences caused by the application of a reference sensor. This paper describes the testing methods of the specially developed validation facility KALFOS for the qualification and evaluation of surface-applied strain sensors. For reliable sensor results, the performance of fibre optic strain patches with and without FBG under combined thermal and mechanical loading was investigated. Additionally, the strain gauge factor of the fibre optic strain patches with FBG was determined experimentally and compared to the specified strain gauge factor. These results will be the basis for the development of guidelines and standards concerning the application of the sensors. KW - Evaluation KW - Qualification KW - Strain transfer KW - Fibre optic sensors KW - Fibre Bragg grating KW - Patch KW - Strain gauge KW - Validation facility KW - Laser extensometer KW - Electronic speckle pattern interferometry PY - 2013 U6 - https://doi.org/10.1088/0957-0233/24/9/094005 SN - 0957-0233 SN - 1361-6501 VL - 24 IS - 9 SP - 094005-1 EP - 094005-7 PB - IOP Publ. Ltd. CY - Bristol AN - OPUS4-29424 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schukar, Vivien A1 - Baitinger, Eugen A1 - Kusche, Nadine A1 - Steinke, F. A1 - Habel, Wolfgang T1 - Use of spectral conditions to separate strain and temperature effects in fibre Bragg grating sensors embedded in load-carrying anisotropic laminates N2 - This work presents a further development of the methods of simultaneous determination of temperature and axial strain using a single fibre Bragg grating (FBG). The reflected spectrum of composite-embedded FBG sensors has been analyzed in order to separate temperature and load effects. We found out that during the curing process of the laminates, a superstructure has been introduced on the FBG. Analyzing this effect, a temperature and strain separation was implemented by simply calculating and comparing the integrated intensity of the spectral response signal. A mathematical four-parametric model has been developed to calculate the reflected spectrum of a superstructured fibre Bragg grating. The mathematically achieved data has been evaluated with experimentally determined data from fibre Bragg gratings embedded in glass-fibre reinforced composite materials. KW - Fibre Bragg grating KW - Patch KW - Four-parametric KW - model KW - Superstructure KW - Temperature KW - Strain PY - 2013 U6 - https://doi.org/10.1007/s11340-013-9773-y SN - 0014-4851 SN - 1741-2765 VL - 54 IS - 3 SP - 421 EP - 429 PB - Springer CY - Norwell, Mass. AN - OPUS4-29452 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -