TY - GEN A1 - Liehr, Sascha A1 - Lenke, Philipp A1 - Wendt, Mario A1 - Krebber, Katerina A1 - Glötzl, R. A1 - Schneider-Glötzl, J. A1 - Gabino, L. A1 - Krywult, L. ED - Bernadette Havranek, ED - Masoud Motavalli, ED - Urs Meier, T1 - Distributed polymer optical fiber sensors in geotextiles for monitoring of earthwork structures T2 - 4th International conference on structural health monitoring of intelligent infrastructure CY - Zurich, Switzerland DA - 2009-07-22 KW - Distributed sensor KW - Optical fiber sensor KW - Geotextile KW - Technical textile KW - POF sensor KW - Structural health monitoring KW - SHM KW - OTDR KW - Fiber optic sensors KW - Polymer optical fibers (POF) KW - Strain sensor PY - 2009 SN - 978-3-905594-52-2 IS - Paper 520 SP - 1 EP - 7(?) CY - Zurich, Switzerland AN - OPUS4-19787 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Liehr, Sascha A1 - Lenke, Philipp A1 - Wendt, Mario A1 - Krebber, Katerina ED - Fu-Kuo Chang, T1 - POF sensors integrated in technical textiles for monitoring of earthwork structures and masonry T2 - Structural health monitoring 2009 - 7th International workshop on structural health monitoring CY - Stanford, CA, USA DA - 2009-09-09 KW - Distributed strain sensor KW - Optical fiber sensor KW - Geotextile KW - Technical textiles KW - POF sensor KW - Structural health monitoring KW - SHM KW - OTDR PY - 2009 SN - 978-1-60595-007-5 VL - 2 SP - 1739 EP - 1746 PB - DEStech Publications, Inc. AN - OPUS4-19960 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Liehr, Sascha A1 - Lenke, Philipp A1 - Wendt, Mario A1 - Krebber, Katerina A1 - Seeger, M. A1 - Thiele, E. A1 - Metschies, H. A1 - Gebreselassie, B. A1 - Münich, J.C. T1 - Polymer optical fiber sensors for distributed strain measurement and application in structural health monitoring N2 - Polymer optical fiber (POF) sensors have the unique ability to measure high strain distributed along the fiber up to 40% using the optical time-domain reflectometry (OTDR) technique. Both, standard PMMA fibers and perfluorinated (PF) graded-index (GI) POF are introduced and evaluated in potential use and applicability. Further, distributed length change measurement based on cross-correlation analysis of the characteristic fiber signature of PF POF is introduced. We conclude the advances in distributed POF strain sensors technology with respect to application in structural health monitoring. Special focus is on the sensor integration into technical textiles for health monitoring of geotechnical structures and masonry structures. Measurement results of sensor-equipped textiles in different model tests are presented, displacement of soil and cracks in retrofitted masonry structures are detected and evaluated. KW - Distributed strain sensor KW - Optical fiber sensor KW - POF sensors KW - Structural health monitoring PY - 2009 DO - https://doi.org/10.1109/JSEN.2009.2018352 SN - 1530-437X SN - 1558-1748 VL - 9 IS - 11 SP - 1330 EP - 1338 CY - New York, NY, USA AN - OPUS4-20311 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lenke, Philipp A1 - Liehr, Sascha A1 - Krebber, Katerina T1 - Improvements of the distributed strain sensor based on optical time domain reflectometry measurement in polymer optical fibers N2 - Sensing characteristics of standard polymer optical fibers (POF) are further studied using the optical time domain reflectometry (OTDR) technique. The level of the backscattering inside POF, which highly increases at locations where strain is applied to the fiber, is further investigated with respect to spectral behavior, strain rate and span of time from the stretching event. An algorithem to overcome the problem of the decrease of spatial resolution as a result of pulse broadening due to modal disperion, is proposed. The research is carried out on the background of the development of a new strain sensor that is integrated in technical textiles. T2 - 17th International Conference on Plastic Optical Fibers (POF 2008) CY - Santa Clara, California, USA DA - 2008-08-25 KW - Distributed strain sensor KW - Optical fiber sensor KW - POF KW - Scatter KW - PMMA KW - Spatial resolution PY - 2008 IS - Paper 1 SP - 1 EP - 5 AN - OPUS4-18210 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Liehr, Sascha A1 - Lenke, Philipp A1 - Wendt, Mario A1 - Krebber, Katerina T1 - Perfluorinated graded-index polymer optical fibers for distributed measurement of strain N2 - Recently, we have proposed, to our knowledge for the first time, to use perfluorinated graded-index polymer optical fiber (POF) for distributed measurement of strain. Thanks to their low attenuation and low modal dispersion compared to standard-POF, this fiber type allows to extend the measurement length to more than 500 meters at increased spatial resolution. In this paper, two mechanisms for strain sensing are introduced. As in standard PMMA POF, strain in the fiber can be detected by evaluating the local backscatter increase occurring at strained fiber sections. Further, we propose, to our knowledge for the first time, a true distributed length change measurement in POF using cross-correlation analysis of the fiber’s characteristic backscatter signature. Using this technique, it is possible to measure relative displacement between different fiber sections avoiding signal fading failures that are inherent in other measurement principles. Cross-sensitivities to the sensor signal, as fiber bends and temperature, are investigated and quantified. T2 - 17th International Conference on Plastic Optical Fibers (POF 2008) CY - Santa Clara, California, USA DA - 2008-08-25 KW - Distributed strain sensor KW - Optical fiber sensor KW - Perfluorinated POF KW - POF sensors PY - 2008 IS - Paper 64 SP - 1 EP - 5 AN - OPUS4-18209 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lenke, Philipp A1 - Krebber, Katerina ED - Jones, J. ED - Culshaw, B. ED - Ecke, W. ED - López-Higuera, J.M. ED - Willsch, R. T1 - A new model to calculate the Rayleigh scattering profiles in polymer optical fibers for distributed strain sensing N2 - This paper presents new methods to calculate and interpret Rayleigh scattering profiles in polymer optical fibers (POF) recorded by optical time domain reflectometry (OTDR). In contrast to Silica glass optical fibers (GOF), POF experience inhomogeneous stress when being strained, resulting in small scattering centers which allow for a new distributed sensor based on POF. New methods to overcome issues like blurring due to modal dispersion, uncertainties due to inhomogenious losses in the fiber and signal degradation due to viscoelastic creep in the polymer, are presented, for the first time to our knowledge. T2 - 20th International conference on optical fibre sensors (Proceedings of SPIE) CY - Edinburgh, Scotland, UK DA - 2009-10-05 KW - POF KW - Distributed sensing KW - Rayleigh KW - Scattering KW - OTDR KW - Distributed strain sensor KW - Optical fiber sensor KW - PMMA KW - Spatial resolution PY - 2009 SN - 978-0-8194-7814-6 DO - https://doi.org/10.1117/12.835361 SN - 0277-786X SP - 75036I-1 - 75036I-4 PB - SPIE, the International Society for Optical Engineering AN - OPUS4-20496 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -