PSI - Issue 28

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J. Weiland et al. / Procedia Structural Integrity 28 (2020) 1249–1257 Weiland et al. / Structural Integrity Procedia 00 (2019) 000–000

Fig. 8: Results – detected light power over stress for POF integrated single lap joint – representative curve

6. Conclusion and outlook We have successfully demonstrated that Structural Health Monitoring of a single lap joint by using a POF is possible. The load applied by the tensile testing machine causes a deformation of the fiber cross sectional shape within the adhesive layer. Using a steel specimen bonded with the 2C-Polyurethan adhesive (3M Scotch-Weld DP 609), the direct relationship between stress and the light output was demonstrated. If the POF is positioned centrally in the joint, meaningful measurement results can be obtained. Structural Health Monitoring by means of polymer optical fibers offers further need for research in the future. The effects on the mechanical behavior of the adhesive POF composite require further investigations. Further investigations are also necessary, especially with regard to the mechanical optical effects of deformation of the POF cross sectional shape on the optical behavior of POF. In the experiments, the optical properties such as the integral light power, the spectral power density distribution (spectrum) and the spatial distribution of the light at the fiber end face (near field) as well as the angle-dependent distribution in the far field (mode distribution) are to be investigated. References [1] DIN-Normenausschuss Schweißen und verwandte Verfahren (NAS), DIN 2304-1 Klebtechnik – Qualitätsanforderungen an Klebprozesse – Teil 1: Prozesskette Kleben, 2016 [2] Gross, A., Lohse, H.: Qualitätssicherung in der Klebtechnik: Die neue DIN 2304 und ihr Nutzen für die Praxis, In: Adhäsion - Kleben & Dichten, Jahrgang 59, Heft 6, Springer Vieweg, Wiesbaden, 2015 [3] Abdel Wahab, M. M.; Hilmy, I.; Ashcroft, I. A.; Crocombe, A. D.: Evaluation of Fatigue Damage in Adhesive Bonding: Part 2: Single Lap Joint. In: Journal of Adhesion Science and Technology 24 (2010)