TY - CONF A1 - Habel, Wolfgang A1 - Kusche, Nadine A1 - Münzenberger, Sven A1 - Schukar, Vivien T1 - KALFOS - a validation facility for strain transfer characterization of surface-applied strain sensors N2 - Strain sensors embedded in or attached to structural components have to measure the real deformation of the structure over the whole period of use. The user must know how reliably installed sensors provide strain measurement results. For this purpose, test facilities or coupon tests are used. In order to characterize the strain transfer quality from the host structure into surface-applied strain sensors, a unique testing facility has been developed. This facility can be used both for fiber optic and resistance strain sensors. Originally developed for fiber Bragg grating based sensors, the KALFOS facility (=calibration of fiber optic sensors) uses Digital Image Correlation (DIC) and Electronic Speckle Pattern Interferometer (ESPI) as unbiased referencing methods. It is possible to determine experimentally the strain transfer mechanism under combined thermal and mechanical loading conditions. This experimental characterization method will reveal weaknesses in commonly used strain sensors, and the investigation of the material systems used for fiber optic and other strain sensors (particularly the coating/substrate - adhesive combination). The KALFOS facility allows matching of specific measurement requirements with environmental conditions. T2 - SAE 2011 AeroTech Congress & Exhibition CY - Toulouse, France DA - 18.10.2011 KW - Fiber optic sensors KW - Structural health monitoring KW - Validation KW - Strain sensor KW - Surface application PY - 2011 U6 - https://doi.org/10.4271/2011-01-2606 IS - Paper 2011-01-2606 SP - 1 EP - 7 AN - OPUS4-24643 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Habel, Wolfgang A1 - Schukar, Vivien ED - Ecke, W. ED - Peters, K.J. ED - Matikas, T.E. T1 - FOS standards and testing methods to validate fibre optic strain measurements N2 - Fiber optic sensors are increasingly used because of their outstanding performance or if special requirements avoid the application of conventional electrical sensors. The scientific background for optical fiber sensors is well developed; however, the characteristic of sensors applied in rather harsh environment are almost always different from characteristics determined in laboratory or before its installation. In order to achieve long-term stable function and reliable measurement data after application and under harsh environmental conditions, guidelines for characterization and specification of sensor components are needed as well as methodologies for testing the sensor performance must be developed. Performance tests carried out revealed that there are still some restrictions with respect to long-term reliable use: first, some sensor products available on the market are not very often appropriately characterized, described and validated; second, application procedures are not always defined due to a lack of understanding the micromechanical issues in the interface zone between sensor and measuring object. Application procedures and profound knowledge of materials behaviour are necessary to get results from the sensor that can be reliably used. The paper describes first guidelines to prove the quality of fiber optic strain sensors, a testing facility developed for unbiased tests and certification of surface-applied sensors as well as result from comparison of commercially available strain sensors. T2 - SPIE-Conference 'Smart sensor phenomena, technology, networks, and systems 2011' CY - San Diego, CA, USA DA - 06.03.2011 KW - Fiber optics KW - Strain sensor KW - Reliability KW - Durability KW - Creep KW - Application KW - Adhesive KW - Standards KW - Guideline KW - Testing PY - 2011 SN - 978-0-8194-8547-2 U6 - https://doi.org/10.1117/12.881238 VL - 7982 SP - 79820O-1 EP - 79820O-12 AN - OPUS4-24271 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -