TY - JOUR A1 - Stajanca, Pavol A1 - Hicke, Konstantin A1 - Krebber, Katerina T1 - Distributed Fiberoptic Sensor for Simultaneous Humidity and Temperature Monitoring Based on Polyimide-Coated Optical Fibers JF - Sensors N2 - Along temperature, humidity is one of the principal environmental factors that plays an important role in various application areas. Presented work investigates possibility of distributed fiberoptic humidity monitoring based on humidity-induced strain measurement in polyimide (PI)-coated optical fibers. Characterization of relative humidity (RH) and temperature response of four different commercial PI- and one acrylate-coated fiber was performed using optical backscattering reflectometry (OBR). The study addresses issues of temperature-humidity cross sensitivity, fiber response stability, repeatability, and the influence of annealing. Acrylate-coated fiber exhibited rather unfavorable nonlinear RH response with strong temperature dependence, which makes it unsuitable for humidity sensing applications. On the other hand, humidity response of PI-coated fibers showed good linearity with fiber sensitivity slightly decreasing at rising temperatures. In the tested range, temperature sensitivity of the fibers remained humidity independent. Thermal annealing was shown to considerably improve and stabilize fiber RH response. Based on performed analysis, a 20 m sensor using the optimal PI-coated fibers was proposed and constructed. The sensor uses dual sensing fiber configuration for mutual decoupling and simultaneous measurement of temperature and RH variations. Using OBR, distributed dual temperature-RH monitoring with cm spatial resolution was demonstrated for the first time. KW - Distributed humidity sensing KW - Fiberoptic sensors KW - Polyimide-coated optical fibers KW - Optical frequency-domain reflectometry KW - Dual sensing PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-498871 DO - https://doi.org/10.3390/s19235279 VL - 19 IS - 23 SP - 5279 PB - MDPI AN - OPUS4-49887 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stajanca, Pavol T1 - Fiberoptic sensors for composite/plastic components monitoring N2 - An overview of Division 8.6 activities on using optical fiber sensors for composite monitoring is given. T2 - Workshop an der TU Chemnitz CY - Chemnitz, Germany DA - 06.05.2019 KW - Fiberoptic sensors KW - Composites KW - Sensor intergration KW - Polymer optical fibers PY - 2019 AN - OPUS4-47969 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stajanca, Pavol A1 - Krebber, Katerina T1 - Investigation of bare and tight buffered optical fibers towards distributed humidity sensing N2 - Humidity is one of principal environmental parameters that plays an important role in various application areas. Distributed humidity/water sensing is sought after in wide range of applications including concrete condition monitoring in civil engineering, SHM of large structures such as dykes or dams, soil moisture measurement in agriculture or leak detection in pipeline or sewage industry. Using humidity-induced strain of specialty hygroscopic coating materials, such as polyimide (PI) seems as the most promising approach so far. In this work, relative humidity and temperature response of different commercial PI-coated and tight-buffer fibers is investigated for the development of distributed humidity sensor. T2 - Seventh European Workshop on Optical Fibre Sensors CY - Limassol, Cyprus DA - 01.10.2019 KW - Distribute fiberoptic sensor KW - Distributed humidity sensing KW - Water ingress detection KW - Optical backscatter reflectometry KW - Tight-buffered fibers KW - Polyimide-coated fibers PY - 2019 AN - OPUS4-49208 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stajanca, Pavol A1 - Krebber, Katerina T1 - Investigation of bare and tight buffered optical fibers towards distributed humidity sensing N2 - Humidity is one of principal environmental parameters that plays an important role in various application areas. Distributed humidity/water sensing is sought after in wide range of applications including concrete condition monitoring in civil engineering, SHM of large structures such as dykes or dams, soil moisture measurement in agriculture or leak detection in pipeline or sewage industry. Using humidity-induced strain of specialty hygroscopic coating materials, such as polyimide (PI) seems as the most promising approach so far. In this work, relative humidity and temperature response of different commercial PI-coated and tight-buffer fibers is investigated for the development of distributed humidity sensor. T2 - Abschlussmeeting des MONALISA-Projekts CY - Berlin, Germany DA - 06.12.2019 KW - Distribute fiberoptic sensor KW - Distributed humidity sensing PY - 2019 AN - OPUS4-49977 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Stajanca, Pavol A1 - Krebber, Katerina ED - Kalli, K. ED - Brambilla, G. ED - O'Keeffe, S. T1 - Investigation of bare and tight-buffered optical fibers towards distributed humidity sensing T2 - Proceedings of SPIE N2 - Humidity is one of principal environmental parameters that plays an important role in various application areas. Using measurement of strain induced in an optical fiber by a water swellable coating represents a promising approach for realization of distributed humidity sensing (DHS). In this work, humidity and temperature response of four different commercial PI-coated fibers and four tight-buffered (TB) fibers is investigated with the aim of evaluating their potential for development of DHS in context of water ingress sensor for high-voltage power cable splices. PI-coated fibers exhibited close-to-linear humidity and temperature response. While the temperature response is relatively coating-independent, magnitude of humidity response was broadly correlated to the relative fiber-to-coating thickness ratio. In contrast, both humidity and temperature response of TB fibers is strongly influenced by buffer type, with Leoni TB900L fiber with Hytrel buffer exhibiting largest humidity and temperature sensitivity. While the response of tight-buffered fibers is generally nonlinear, roughly three-times higher humidity response can be achieved with TB900L compared to the most sensitive PI-coated fiber. Using the TB fiber can be, therefore, advantageous for simpler water detection applications, such as one targeted in this study, when larger sensitivity is more important than the linear response of the sensor. KW - Distribute fiberoptic sensor KW - Distributed humidity sensing KW - Water ingress detection KW - Optical backscatter reflectometry KW - Tight-buffered fibers KW - Polyimide-coated fibers PY - 2019 SN - 978-1-51063-124-3 DO - https://doi.org/10.1117/12.2539819 VL - 11199 SP - 111991X-1 PB - SPIE CY - Bellingham, Washington, USA AN - OPUS4-49207 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stajanca, Pavol A1 - Hicke, Konstantin A1 - Kapa, Thomas A1 - Krebber, Katerina T1 - MONALISA-Teilprojekt: Adaption erforschter faseroptischer Messverfahren für die Entwicklung und Bereitstellung fehlender Sensortechnik für vordringliche Mess- und Monitoringaufgaben in künftigen Stromnetzen N2 - Das Teilprojekt zielt auf die Entwicklung integrierbarer verteilter faseroptischer Sensoren (u. a. verteilte Brillouin-Sensorik, verteilte akustische Sensorik) für die Langzeitüberwachung von Betriebsparametern in Hoch- und Mittelspannungskabelanlagen. Mit Hilfe der Sensoren sollen unzulässige Dehnungen, Übertemperaturen und das Eindringen von Feuchte, z. B. in Unterseekabeln, detektiert werden. Das Teilprojekt beinhaltet ebenfalls die Entwicklung integrierfähiger Sensoren für verteiltes (vibro-)akustisches Monitoring an Unterseekabeln, vor allem zur Lokalisierung und zur Abwendung von Störfällen und Schäden durch äußere mechanische Einflüsse (z. B. Ankerwurf). T2 - Abschlussmeeting des MONALISA-Projekts CY - Berlin, Germany DA - 06.12.2019 KW - Verteilte faseroptische Sensorik KW - Stromnetzen KW - Stromkabelüberwachung PY - 2019 AN - OPUS4-49976 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stajanca, Pavol A1 - Krebber, Katerina T1 - Neue Entwicklungen im Bereich der faseroptischen Sensorik für Anwendungen in der Kerntechnik N2 - Fiberoptic sensors found numerous applications in various areas of nuclear industry. In this presentation, an overview of state-of-the art of fiberoptic sensors for monitoring tasks in radiation environments is given. T2 - Workshop mit Gesellschaft für Anlagen- und Reaktorsicherheit (GRS) GmbH CY - Berlin, Germany DA - 09.05.2019 KW - Fiberoptic sensors KW - Nuclear waste disposal KW - Radiation monitoring KW - Distributed sensing PY - 2019 AN - OPUS4-47968 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stajanca, Pavol A1 - Krebber, Katerina T1 - Niches of fiberoptic sensing: from large-strain applications to acoustic emission monitoring N2 - Fibreoptic sensors (FOS) represent sensing technology with small footprint, low invasiveness, electromagnetic passivity and immunity, plus potential for remote and real-time monitoring. Modern FOS techniques allow truly temporally- and spatially-continuous monitoring over extended distances; a feature not attainable with any other sensing technology. Moreover, depending on their particular material composition and design, optical fibres can be made resistant to high temperatures, chemicals and ionizing radiation. Due to this unique combination of advantageous properties, ever since their emergence, FOS have been attracting considerable attention for monitoring tasks in harsh, hazardous and difficult-to-access locations. The potential of FOS has been recognized also in the field of radioactive waste management and fibreoptic sensors belong to the most promising technologies for nuclear waste repositories (NWR) monitoring. Vast majority of distributed fibreoptic sensor applications rely on use of silica-based optical fibres as sensing elements. At the same time, distributed measurement of local temperature and strain along the fibre are the most common monitoring tasks addressed by fibreoptic sensors. Nevertheless, FOS offer much larger flexibility both in terms of utilized sensing fibre as well as targeted measurand. In this contribution, we will review some of more alternative implementations of FOS that are being explored at “Fibre Optic Sensors” division of Federal Institute for Material Research and Testing (BAM), in Berlin. The main focus will be twofold. On one side, we will address FOS applications with polymer optical fibres (POF), that may enable monitoring of large strains (>100%) and high-sensitivity radiation detection. On the other side, we will present our activities in the area of distributed acoustic sensing (DAS); one of the most recent developments in the fibreoptic sensing field enabling highly-dynamic vibration sensing with nanostrain sensitivity. We will introduce the principles of the addressed FOS technologies, present application examples from our case studies, discuss advantages and limitations of the techniques and highlight their potential for NWR monitoring. T2 - Modern 2020 Final Conference CY - Paris, France DA - 09.04.2019 KW - Fiberoptic sensors KW - Nuclear waste disposal KW - Polymer optical fibers KW - Distributed acoustic sensing KW - Distributed radiation monitoring PY - 2019 UR - http://www.modern2020.eu/final-conference/programme.html AN - OPUS4-47789 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -