@article{WeilandKunzeLuberetal.2023, author = {Weiland, Josef and Kunze, Billy and Luber, Michael and Kr{\"u}ger, Naomi and Schiebahn, Alexander and Engelbrecht, Rainer and Reisgen, Uwe}, title = {Structural Health Monitoring of Adhesively Bonded Pipe-to-Socket Joints by Integration of Polymer Optical Fibers and Their Load-Dependent Transmission Properties}, series = {Sensors}, volume = {23}, journal = {Sensors}, number = {10}, publisher = {MDPI AG}, issn = {1424-8220}, doi = {10.3390/s23104748}, year = {2023}, abstract = {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).}, language = {en} } @article{WeilandKunzeLuberetal.2023, author = {Weiland, Josef and Kunze, Billy and Luber, Michael and Kr{\"u}ger, Naomi and Schiebahn, Alexander and Engelbrecht, Rainer and Reisgen, Uwe}, title = {Structural Health Monitoring of Adhesively Bonded Pipe-to-Socket Joints by Integration of Polymer Optical Fibers and Their Load-Dependent Transmission Properties}, series = {Sensors}, volume = {23}, journal = {Sensors}, number = {10}, publisher = {MDPI AG}, issn = {1424-8220}, doi = {10.3390/s23104748}, year = {2023}, abstract = {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).}, language = {en} } @article{WeilandSchiebahnReisgenetal.2023, author = {Weiland, Josef and Schiebahn, Alexander and Reisgen, Uwe and Luber, Michael and Ziemann, Olaf and Engelbrecht, Rainer}, title = {Zustands{\"u}berwachung struktureller Klebungen unter Scherbeanspruchung durch Integration einer optischen Polymerfaser}, series = {Schweißen und Schneiden}, journal = {Schweißen und Schneiden}, number = {8}, publisher = {DSV Media}, address = {D{\"u}sseldorf}, pages = {542-547}, year = {2023}, abstract = {Das im hier vorgestellten Forschungsrojekt KlebPOF untersuchte Sensorkonzept der Zustands{\"u}berwachung von Klebungen basiert auf der Integration eines Kunststoff-Lichtwellenleiters (polymere optische Faser, POF) in die Klebung. Die {\"a}hnlichen mechanischen Eigenschaften von POF und Klebstoff, beides Kunststoffe, haben zur Folge, dass Beanspruchungen des Klebstoffs auf die POF {\"u}bertragen 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 f{\"u}r den Einsatz zur Zustands{\"u}berwachung von Klebverbindungen interpretiert. Die Ergebnisse an Couponproben zeigen, dass sich die Methode insbesondere f{\"u}r 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 {\"A}nderungen im Sensorsignal fr{\"u}hzeitig vor Versagen detektierbar. Diese {\"A}nderung konnte mit kosteng{\"u}nstigen opto-elektronischen Komponenten detektiert werden. Damit eignet sich die Methode f{\"u}r eine integrale Zustands{\"u}berwachung der gesamten Klebung ohne Ortsaufl{\"o}sung, um einen kosteng{\"u}nstigen Sensor f{\"u}r den Feldeinsatz zu erm{\"o}glichen.}, language = {de} } @incollection{WeilandLuberRostanetal.2022, author = {Weiland, Josef and Luber, Michael and Rostan, Katharina and Schiebahn, Alexander and Engelbrecht, Rainer and Reisgen, Uwe}, title = {Strain Monitoring of a Structural Adhesive Bond by Embedding a Polymer Optical Fiber}, series = {European Workshop on Structural Health Monitoring , Vol I}, booktitle = {European Workshop on Structural Health Monitoring , Vol I}, publisher = {Springer International Publishing}, address = {Cham}, isbn = {9783031072536}, issn = {2366-2557}, doi = {10.1007/978-3-031-07254-3_75}, pages = {745 -- 754}, year = {2022}, abstract = {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.}, language = {en} } @inproceedings{EngelbrechtRostanWeilandetal.2022, author = {Engelbrecht, Rainer and Rostan, Katharina and Weiland, Josef and Luber, Michael and Schiebahn, Alexander and Reisgen, Uwe}, title = {Modal Distribution in Polymer Optical Fibers as Sensor for Load Monitoring in Semi-Structural Adhesive Bonds}, series = {27th International Conference on Optical Fiber Sensors}, booktitle = {27th International Conference on Optical Fiber Sensors}, publisher = {Optica Publishing Group}, address = {Washington, D.C.}, isbn = {978-1-957171-14-2}, doi = {10.1364/OFS.2022.W2.3}, year = {2022}, abstract = {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.}, language = {en} }