TY - JOUR A1 - Weiland, Josef A1 - Kunze, Billy A1 - Luber, Michael A1 - Krüger, Naomi A1 - Schiebahn, Alexander A1 - Engelbrecht, Rainer A1 - Reisgen, Uwe T1 - Structural Health Monitoring of Adhesively Bonded Pipe-to-Socket Joints by Integration of Polymer Optical Fibers and Their Load-Dependent Transmission Properties JF - Sensors N2 - Adhesively bonded pipe-to-socket joints are used in numerous industrial applications. One example is in the transport of media, e.g., in the gas industry or in structural joints for such sectors as construction, wind energy, and the vehicle industry. To monitor such load-transmitting bonded joints, this study investigates a method based on the integration of polymer optical fibers into the adhesive layer. Previous methods for monitoring the condition of pipes, such as acoustic or ultrasonic methods or the use of glass fiber optic-based sensors (FBG or OTDR), are very complex in methodology and require cost-intensive (opto-) electronic devices to generate and evaluate the sensor signals; they are therefore unsuitable for large-scale use. The method investigated in this paper is based on the measurement of integral optical transmission with a simple photodiode under increasing mechanical stress. When tried at coupon level (single-lap joint), the light coupling was varied to obtain a significant load-dependent sensor signal. Based on an angle-selective coupling of 30° to the fiber axis, a drop of 4% of the optically transmitted light power by a load of 8 N/mm2 can be detected for the adhesively bonded pipe-to-socket joint with the structural adhesive Scotch Weld DP810 (2C acrylate). KW - Fiber optics KW - Adhesive bonds KW - Sensors Y1 - 2023 U6 - https://doi.org/10.3390/s23104748 SN - 1424-8220 VL - 23 IS - 10 PB - MDPI AG ER - TY - JOUR A1 - Weiland, Josef A1 - Kunze, Billy A1 - Luber, Michael A1 - Krüger, Naomi A1 - Schiebahn, Alexander A1 - Engelbrecht, Rainer A1 - Reisgen, Uwe T1 - Structural Health Monitoring of Adhesively Bonded Pipe-to-Socket Joints by Integration of Polymer Optical Fibers and Their Load-Dependent Transmission Properties JF - Sensors N2 - Adhesively bonded pipe-to-socket joints are used in numerous industrial applications. One example is in the transport of media, e.g., in the gas industry or in structural joints for such sectors as construction, wind energy, and the vehicle industry. To monitor such load-transmitting bonded joints, this study investigates a method based on the integration of polymer optical fibers into the adhesive layer. Previous methods for monitoring the condition of pipes, such as acoustic or ultrasonic methods or the use of glass fiber optic-based sensors (FBG or OTDR), are very complex in methodology and require cost-intensive (opto-) electronic devices to generate and evaluate the sensor signals; they are therefore unsuitable for large-scale use. The method investigated in this paper is based on the measurement of integral optical transmission with a simple photodiode under increasing mechanical stress. When tried at coupon level (single-lap joint), the light coupling was varied to obtain a significant load-dependent sensor signal. Based on an angle-selective coupling of 30° to the fiber axis, a drop of 4% of the optically transmitted light power by a load of 8 N/mm2 can be detected for the adhesively bonded pipe-to-socket joint with the structural adhesive Scotch Weld DP810 (2C acrylate). KW - Fiber optics KW - Sensors KW - Adhesive bonding Y1 - 2023 U6 - https://doi.org/10.3390/s23104748 SN - 1424-8220 VL - 23 IS - 10 PB - MDPI AG ER - TY - JOUR A1 - Weiland, Josef A1 - Schiebahn, Alexander A1 - Reisgen, Uwe A1 - Luber, Michael A1 - Ziemann, Olaf A1 - Engelbrecht, Rainer T1 - Zustandsüberwachung struktureller Klebungen unter Scherbeanspruchung durch Integration einer optischen Polymerfaser JF - Schweißen und Schneiden N2 - Das im hier vorgestellten Forschungsrojekt KlebPOF untersuchte Sensorkonzept der Zustandsüberwachung von Klebungen basiert auf der Integration eines Kunststoff-Lichtwellenleiters (polymere optische Faser, POF) in die Klebung. Die ähnlichen mechanischen Eigenschaften von POF und Klebstoff, beides Kunststoffe, haben zur Folge, dass Beanspruchungen des Klebstoffs auf die POF übertragen werden. Die Auswirkungen einer Belastung auf die optischen Eigenschaften des Lichtwellenleiters werden in Bezug auf die transmittierte Lichtleistung sowie auf den Einfluss der Winkelverteilung der aus der Faser austretenden Lichtstrahlen im Fernfeld untersucht und für den Einsatz zur Zustandsüberwachung von Klebverbindungen interpretiert. Die Ergebnisse an Couponproben zeigen, dass sich die Methode insbesondere für semi-strukturelle Klebstoffe, wie zum Beispiel 2K-Polyurethane oder 2K-Methylmethacrylate und eine Beanspruchung der Klebung auf Scherung gut eignet. In den Untersuchungen an dem Funktionsmuster, einer Rohr-Muffe-Klebung, waren sehr deutliche Änderungen im Sensorsignal frühzeitig vor Versagen detektierbar. Diese Änderung konnte mit kostengünstigen opto-elektronischen Komponenten detektiert werden. Damit eignet sich die Methode für eine integrale Zustandsüberwachung der gesamten Klebung ohne Ortsauflösung, um einen kostengünstigen Sensor für den Feldeinsatz zu ermöglichen. KW - Kleben KW - Werkstoffragen Y1 - 2023 IS - 8 PB - DSV Media CY - Düsseldorf ER - TY - CHAP A1 - Weiland, Josef A1 - Luber, Michael A1 - Rostan, Katharina A1 - Schiebahn, Alexander A1 - Engelbrecht, Rainer A1 - Reisgen, Uwe T1 - Strain Monitoring of a Structural Adhesive Bond by Embedding a Polymer Optical Fiber T2 - European Workshop on Structural Health Monitoring , Vol I N2 - In recent decades, adhesive bonding technology has become increasingly important in all industrial sectors, for example in the aerospace industry, the automotive industry or the construction industry. This is accompanied by an increased need for monitoring of adhesive bonds, especially for load-bearing, structural joints. In order to detect a possible failure at an early stage, this work is investigating a cost-effective sensor principle based on embedding of a polymer optical fiber (POF) into the adhesive layer. The strain and stress behavior of the adhesive bond are transferred to the POF and change its light-guiding properties. In the presented work, different light coupling conditions into the fiber (full excitation and angle-selective excitation) and different measurable quantities of the transmitted light decoupled from the fiber (photocurrent and far-field) are studied, to find an optimum sensor performance. The combination of a structural polyurethane adhesive with commercially available POF is investigated. The results show a high potential of the method for simple photocurrent measurement (transmission loss of 8% by half of maximum load) and an even more sensitive sensor effect for mode-dependent light power measurement. Y1 - 2022 SN - 9783031072536 U6 - https://doi.org/10.1007/978-3-031-07254-3_75 SN - 2366-2557 SP - 745 EP - 754 PB - Springer International Publishing CY - Cham ER - TY - CHAP A1 - Engelbrecht, Rainer A1 - Rostan, Katharina A1 - Weiland, Josef A1 - Luber, Michael A1 - Schiebahn, Alexander A1 - Reisgen, Uwe T1 - Modal Distribution in Polymer Optical Fibers as Sensor for Load Monitoring in Semi-Structural Adhesive Bonds T2 - 27th International Conference on Optical Fiber Sensors N2 - PMMA polymer optical fibers embedded in semi-structural polyurethane adhesive bonds serve as economical load sensor for structural health monitoring by evaluating load-dependent optical transmission as well as modal distribution measured by a far-field camera. Scaling of sensor quantities by the sensitive fiber length is shown. KW - Fiber optics KW - Adhesive bonds KW - Sensors Y1 - 2022 SN - 978-1-957171-14-2 U6 - https://doi.org/10.1364/OFS.2022.W2.3 PB - Optica Publishing Group CY - Washington, D.C. ER -