@article{WeilandBartholomeeLuberetal.2022, author = {Weiland, J. and Bartholomee, W. and Luber, M. and Schiebahn, A. and Engelbrecht, R. and Reisgen, U.}, title = {Investigation into the mechanical behavior of a polymer optical fiber embedded in a structural adhesive}, series = {International Journal of Adhesion and Adhesives}, volume = {117}, journal = {International Journal of Adhesion and Adhesives}, publisher = {Elsevier BV}, issn = {0143-7496}, doi = {10.1016/j.ijadhadh.2021.103018}, pages = {9}, year = {2022}, abstract = {To guaranty a safe load transfer through adhesively bonded joints, Structural Health Monitoring (SHM) methods that allow for permanent monitoring of the structural bond condition, are becoming more and more important. To meet this increasing demand, a novel approach for SHM of adhesively bonded joints by use of integrated Polymer Optical Fibers (POF) has been demonstrated in previous work. The sensor operating principle is based on strain transfer from the structural adhesive to the integrated POF. This strain transfer leads to a deformation of the POF cross-sectional shape and in that way affects the optical light propagation in the POF. In the current work, numerical and experimental results are presented into the mechanical behavior of embedded POF in adhesive bulk specimens subjected to tensile loading. Local deformations of both the POF (Asahi Kasei DB 500) and the structural adhesive (3 M Scotch Weld DP410) are evaluated using Digital Image Correlation (DIC). In the loading direction, a linear correlation is shown between strain inside the POF core and strain of the surrounding adhesive. Tests results, as well as fracture analysis, show a highly ductile behavior and failure of the POF cladding material and the interface between the POF core and annular cladding.}, language = {en} } @inproceedings{EngelbrechtRostanWeilandetal.2022, author = {Engelbrecht, R. and Rostan, K. and Weiland, J. and Luber, M. and Schiebahn, A. and Reisgen, U.}, 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.}, 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} } @article{WeilandLuberSeewaldetal.2020, author = {Weiland, J. and Luber, M. and Seewald, R. and Schiebahn, A. and Engelbrecht, R. and Reisgen, U.}, title = {Structural Health Monitoring of Adhesively Bonded Joints: Proposing a new Method by use of Polymer Optical Fibers}, series = {Procedia Structural Integrity}, volume = {28}, journal = {Procedia Structural Integrity}, publisher = {Elsevier BV}, issn = {2452-3216}, doi = {10.1016/j.prostr.2020.11.106}, pages = {1249 -- 1257}, year = {2020}, abstract = {According to the current state of the art, adhesively bonded joints cannot be tested completely non-destructively. This is the main motivation to permanently monitor adhesively bonded joints in order to record their structural integrity and - as a result - to ensure safe load transmission. By the use of permanent non-destructive Structural Health Monitoring (SHM) methods, structural damages in the adhesive bond can be detected at an early stage. This paper presents a new method for monitoring the structural integrity of adhesively bonded joints by integrating a Polymer Optical Fiber (POF) into the adhesive layer. The sensor concept is based on a deformation transfer from the adhesive to the POF, which results in a change in the cross-sectional shape of the POF. The cross-sectional shape influences the optical light propagation in the POF, which can be detected by simple optical measuring devices. The paper describes the general principle and first results of investigations on a structural adhesive (3M Scotch-Weld DP 609). The sensor signal is in a good relation to the stress state of the adhesive layer.}, language = {en} } @article{WeilandLuberSeewaldetal.2020, author = {Weiland, J. and Luber, M. and Seewald, R. and Schiebahn, A. and Engelbrecht, R. and Reisgen, U.}, title = {Structural Health Monitoring of Adhesively Bonded Joints: Proposing a new Method by use of Polymer Optical Fibers}, series = {Procedia Structural Integrity}, volume = {28}, journal = {Procedia Structural Integrity}, publisher = {Elsevier BV}, issn = {2452-3216}, doi = {10.1016/j.prostr.2020.11.106}, pages = {1249 -- 1257}, year = {2020}, abstract = {According to the current state of the art, adhesively bonded joints cannot be tested completely non-destructively. This is the main motivation to permanently monitor adhesively bonded joints in order to record their structural integrity and - as a result - to ensure safe load transmission. By the us e of permanent non-destructive Structural Health Monitoring (SHM) methods, structural damages in the adhesive bond can be detected at an early stage. This paper presents a new method for monitoring the structural integrity of adhesively bonded joints by integrating a Polymer Optical Fiber (POF) into the adhesive layer. The sensor concept is based on a deformation transfer from the adhesive to the POF, which results in a change in the cross-sectional shape of the POF. The cross-sectional shape influences the optical light propagation in the POF, which can be detected by simple optical measuring devices. The paper describes the general principle and first results of investigations on a structural adhesive (3M Scotch-Weld DP 609). The sensor signal is in a good relation to the stress state of the adhesive layer.}, language = {en} }