TY - CONF A1 - Wosniok, Aleksander T1 - Smart geosynthetics for structural health monitoring applications N2 - Responding to a growing need for intelligent monitoring of critical geotechnical and civil infrastructures, new multifunctional geotextiles and geogrids with integrated optical fibers were developed and investigated within several research projects. Such smart two-dimensional geosynthetics intercorporating optical fibers as distributed sensors provide solutions both for soil reinforcement, erosion control, drainage or environmental protection and for cost-effective monitoring of critical mechanical deformations and temperature distribution in geotechnical and masonry structures at the same time. The integrated fiber optic sensors provide online information about the condition of the monitored structure and about the occurrence and localization of any damage or degradation for the purpose of preventing a total collapse. The optical fibers have a serious advantage over other kinds of sensors due to their fibrous nature, so they can be ideally processed like standard textile yarns. The monitoring of extended geotechnical structures like dikes, dams, railways, embankments or slopes requires sensor technologies with measurement lengths of at least some hundred meters which can be realized by the use of silica fibers. However, the integration of silica fibers into geosynthetics during the manufacturing process experienced problems of sensor brittleness, low strain range not exceeding 2 % and bending-related attenuation increase optimized to the value of 1.5 dB/km. Unlike silica fibers, the integration of polymer optical fibers (POFs) into various geosynthetics was easily achieved free of bending losses enabling distributed high strain measurements up to 40 % using PMMA POFs. The first industrial product GEDISE based on a geogrid with integrated PMMA POFs is on the market. Due to the five times lower attenuation of low-loss perfluorinated graded-index POFs (PFGI-POFs), compared to PMMA POFs, the measurement range can be extended to 500 m. The low-loss PFGI-POFs offer the possibility of implementation of Brillouin optical fiber frequency domain analysis (BOFDA) which will significantly improve the measurement accuracy and spatial resolution in comparison with existing POF-based distributed measurement methods like POF OTDR. The development of a distributed Brillouin system based on PFGI-POFs is in progress. T2 - The Fiber Society’s Spring 2017 Conference CY - Institut für Textiltechnik der RWTH Aachen, Germany DA - 17.05.2017 KW - Smart geosynthetics KW - Sensor-based geotextiles KW - Fiber optic sensor KW - Distributed sensing PY - 2017 AN - OPUS4-40319 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wosniok, Aleksander A1 - Liehr, Sascha T1 - Health monitoring of geotechnical structures by distributed fiber optic sensors N2 - Health monitoring of ground movement via highly sensitive fiber optic sensors allows operators to detect early potential or ongoing failures in critical geotechnical structures. Particularly, the fiber optic sensors can be embedded in geosynthetics which are nowadays widely used in many geotechnical applications including earth dikes, railway embankments, landfill liners, quarries and mines. Thereby, such smart geosynthetics can be used for reinforcement, layer separation, filtration or drainage while the embedded fiber optic sensors provide information about the condition of the geotechnical structures in real time. The paper highlights the results achieved in this innovative field in the framework of several German and European projects. The presented measurement methods for long-term monitoring are based on Brillouin scattering in silica glass optical fibers (GOFs) and optical time domain reflectometry (OTDR) in polymer optical fibers (POFs). T2 - AMA Conferences 2017 Sensor 2017 CY - Nürnberg, Germany DA - 30.05.2017 KW - Fiber optic sensor KW - Distributed sensor KW - Smart geosynthetics KW - Brillouin sensor KW - OTDR PY - 2017 SN - 978-3-9816876-4-4 DO - https://doi.org/10.5162/sensor2017/B7.4 SP - 280 EP - 285 PB - AMA Service GmbH CY - Wunstorf AN - OPUS4-40514 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wosniok, Aleksander A1 - Sporea, D. A1 - Neguţ, D. A1 - Krebber, Katerina T1 - Gamma radiation influence on silica optical fibers measured by optical backscatter reflectometry and Brillouin sensing technique N2 - We have studied the influence of gamma rays on physical properties of different commercially available silica optical fibers stepwise irradiated up to a total dose of 100 kGy. The detection of radiation-induced changes in silica glass offers the possibility of using selected optical fibers as distributed radiation sensors. The measurements performed by us were based on optical backscatter reflectometry and Brillouin distributed sensing. The measurement methods enable an analysis of radiation-induced modification of the group refractive index and density of the optical fibers. The most distinct physical effect observed by us concerns the increase of the optical attenuation with rising total radiation doses. Quantitative measurement results indicate a crucial impact of fiber dopants on radiation-induced physical and sensory characteristics of silica optical fibers affected by differences in fiber fabrication techniques. Based on the obtained results, the suitability of distributed Brillouin sensing for dosimetry applications seems to be improved by modifying the refractive index profile of the fiber core. T2 - Sixth European Workshop on Optical Fibre Sensors CY - Limerick, IRL DA - 31.05.2016 KW - Brillouin frequency shift KW - Lonizing radiation KW - Gamma radiation KW - Radiation dosimetry KW - Optical fiber sensor KW - Brillouin scattering KW - Distributed measurement KW - Backscatter reflectometry PY - 2016 SN - 978-1-5106-0219-9 DO - https://doi.org/10.1117/12.2236678 SN - 0277-786X VL - 9916 SP - Article Number: 99162J PB - Spie-Int Soc Optical Engineering CY - Bellingham, WA, USA AN - OPUS4-37083 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wosniok, Aleksander T1 - Gamma radiation influence on silica optical fibers measured by optical backscatter reflectometry and Brillouin sensing technique N2 - We have studied the influence of gamma rays on physical properties of different commercially available silica optical fibers stepwise irradiated up to a total dose of 100 kGy. The detection of radiation-induced changes in silica glass offers the possibility of using selected optical fibers as distributed radiation sensors. The measurements performed by us were based on optical backscatter reflectometry and Brillouin distributed sensing. The measurement methods enable an analysis of radiation-induced modification of the group refractive index and density of the optical fibers. The most distinct physical effect observed by us concerns the increase of the optical attenuation with rising total radiation doses. Quantitative measurement results indicate a crucial impact of fiber dopants on radiation-induced physical and sensory characteristics of silica optical fibers affected by differences in fiber fabrication techniques. Based on the obtained results, the suitability of distributed Brillouin sensing for dosimetry applications seems to be improved by modifying the refractive index profile of the fiber core. T2 - Sixth European Workshop on Optical Fibre Sensors CY - Limerick, IRL DA - 31.05.2016 KW - Brillouin frequency shift KW - Ionizing radiation KW - Gamma radiation KW - Radiation dosimetry KW - Optical fiber sensor KW - Brillouin scattering KW - Distributed measurement KW - Backscatter reflectometry PY - 2016 AN - OPUS4-37088 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wosniok, Aleksander T1 - Distributed Brillouin fiber optic sensor system for long-term structural health T2 - XVI Technical Dam Control International Conference CY - Wierchomla Mala, Polanc DA - 2015-09-29 PY - 2015 AN - OPUS4-34494 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Liehr, Sascha A1 - Krebber, Katerina A1 - Steffen, Milan A1 - Wosniok, Aleksander T1 - Fördermaßnahme KMU-innovativ: Informations- und Kommunikationstechnologie (IKT), EMS-261-003 (Digital OFDR - Entwicklung der digitalen Frequenzbereichsanalyse zur verteilten Rückstreumessung in optischen Fasern-Teilvorhaben: Sensorverfahren und Systembetrachtung / Schlussbericht zum Teilvorhaben KW - Digital OFDR KW - Verteilte Rückstreumessung KW - Frequenzbereichsanalyse PY - 2015 IS - BAM Vh 8158 SP - 1 EP - 45 CY - Berlin AN - OPUS4-34170 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wosniok, Aleksander A1 - Krebber, Katerina T1 - Distributed Brillouin fiber optic sensor system for long-term structural health monitoring N2 - We report on the development of a distributed fiber optical sensor system for structural health monitoring of largc-scale geotechnical and civil infrastructures. The system is based on Brillouin frequency domain analysis (BOFDA) for distributed measurement of strain and temperature along Standard silica optical fibers used as sensors. By additional incorporation of the fiber optic sensors in geosynthetics, two-dimensional sensors can be realized. Such smart geosynthetics can be used for reinforeerneut of geotechnical and masonry structures and the embedded fiber optic sensors can provide information about the condition of the structures and detect the presence of any damages and destructions in real time. T2 - 16th International conference 'Technical dam control' CY - Wierchomla Mala, Poland DA - 29.09.2015 KW - Distributed fiber optical sensor KW - Brillouin frequency domain analysis KW - Smart geosynthetics KW - Structural health monitoring PY - 2015 SN - 978-83-64979-09-5 SP - 271 EP - 278 AN - OPUS4-34728 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wosniok, Aleksander T1 - Health monitoring of geotechnical structures by distributed fiber optic sensors N2 - Health monitoring of ground movement via highly sensitive fiber optic sensors allows operators to detect early potential or ongoing failures in critical geotechnical structures. Particularly, the fiber optic sensors can be embedded in geosynthetics which are nowadays widely used in many geotechnical applications including earth dikes, railway embankments, landfill liners, quarries and mines. Thereby, such smart geosynthetics can be used for reinforcement, layer separation, filtration or drainage while the embedded fiber optic sensors provide information about the condition of the geotechnical structures in real time. The paper highlights the results achieved in this innovative field in the framework of several German and European projects. The presented measurement methods for long-term monitoring are based on Brillouin scattering in silica glass optical fibers (GOFs) and optical time domain reflectometry (OTDR) in polymer optical fibers (POFs). T2 - AMA Conferences 2017 Sensor 2017 CY - Nürnberg, Germany DA - 30.05.2017 KW - Fiber optic sensor KW - Distributed sensor KW - Smart geosynthetics KW - Brillouin sensor KW - OTDR PY - 2017 AN - OPUS4-40523 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schreier, Andy A1 - Jeschke, T. A1 - Petermann, K. A1 - Wosniok, Aleksander A1 - Krebber, Katerina T1 - Analytical model for mode-based insertion loss in ball-lensed coupling of graded-index silica and polymer fibres N2 - Analytical model for ball-lensed couplers to calculate the insertion loss for each optical mode. The basis for the calculation are commercial perfluorinated polymer optical (PFGI-POFs) and silica based fibres (SOFs). The modal power distribution for given misalignments are presented as well as the reflection-based losses at all optical interfaces. Additionally, the ball-lensed interconnection between PFGI-POF and SOF was theoretically demonstrated. T2 - POF 2017: 26th International Conference on Plastic Optical Fibres CY - Aveiro, Portugal DA - 13.09.2017 KW - Polymer optical fibre KW - Optical connector PY - 2017 VL - 2017 SP - 1 EP - 4 AN - OPUS4-41979 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krebber, Katerina A1 - Lenke, Philipp A1 - Liehr, Sascha A1 - Nöther, Nils A1 - Wendt, Mario A1 - Wosniok, Aleksander T1 - Protection of critical infrastructure using fiber optic sensors embedded in technical textiles N2 - Terrorists and criminals more and more attack and destroy important infrastructures like routes, railways, bridges, tunnels, dikes and dams, important buildings. Therefore, reliable on-line and long-term monitoring systems are required to protect such critical infrastructures. Fiber optic sensors are well-suited for that. They can be installed over many kilometers and are able to measure continuously distributed strain, pressure, temperature and further mechanical and physical quantities. The very tiny optical fibers can be integrated into structures and materials and can provide information about any significant changes or damages of the structures. These so-called smart materials and smart structures are able to monitor itself or its environment. Particularly smart technical textiles with embedded fiber optic sensors have become very attractive because of their high importance for the structural health monitoring of geotechnical and masonry infrastructures. Such textiles are usually used for reinforcement of the structures; the embedded fiber optic sensors provide information about the condition of the structures and detect the presence of any damages and destructions in real time. Thus, critical infrastructures can be preventively protected. The paper will introduce this innovative field and will present the results achieved within several German and European projects. T2 - Fiber optic sensors and applications VII CY - Orlando, FL, USA DA - 2010-04-07 KW - Distributed sensors KW - Brillouin sensors KW - Polymer optical fibers (POF) KW - POF sensors KW - POF OTDR KW - Strain sensors KW - Technical textiles KW - Geotextiles KW - Fiber optic sensors PY - 2010 SN - 9780819481412 DO - https://doi.org/10.1117/12.851013 SN - 0277-786X VL - 7677 IS - 767707 SP - 1 EP - 14 PB - SPIE, the International Society for Optical Engineering CY - Bellingham, Wash. AN - OPUS4-21675 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -