TY - JOUR A1 - Munzke, Dorit A1 - Kraus, David A1 - Eisermann, René A1 - Kübler, Stefan A1 - Schukar, Marcus A1 - Nagel, Lukas A1 - Hickmann, Stefan A1 - Trappe, Volker T1 - Distributed fiber-optic strain sensing with millimeter spatial resolution for the structural health monitoring of multiaxial loaded GFRP tube specimens JF - Polymer Testing N2 - Due to their high strength-to-weight ratio and excellent fatigue resistance, glass fiber reinforced polymers (GFRP) are used as a construction material in a variety of applications including composite high-pressure gas storage vessels. Thus, an early damage detection of the composite material is of great importance. Material degradation can be determined via measuring the distributed strain profile of the GFRP structures. In this article, swept wavelength interferometry based distributed strain sensing (DSS) was applied for structural health monitoring of internal pressure loaded GFRP tube specimens. Measured strain profiles were compared to theoretical calculation considering Classical Lamination Theory. Reliable strain measurements with millimeter resolution were executed even at elongations of up to 3% in the radial direction caused by high internal pressure load. Material fatigue was localized by damaged-induced strain changes during operation, and detected already at 40% of burst pressure. KW - GFRP KW - Swept wavelength interferometry KW - Distributed fiber optic sensing KW - Material degradation KW - Structural health monitoring PY - 2019 DO - https://doi.org/10.1016/j.polymertesting.2019.106085 SN - 0142-9418 VL - 80 SP - 106085 PB - Elsevier Ltd. AN - OPUS4-48950 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Jan P. A1 - Krankenhagen, Rainer T1 - Optimizing thermographic testing of thick GFRP plates by assessing the real energy absorbed within the material JF - Composite Structures N2 - Active thermography is a well suited non-destructive testing method for the challenging inspection of wind rotor blades. Since the GFRP structures are up to some centimetres thick, long pulse heating is required to provide an appropriate energy input into the structure. So far, no best practice exists to guarantee a reliable detection of deep-lying flaws. In this work, a step wedge specimen having a maximum thickness of 34mm is systematically investigated by experiment and well-matched simulations to assess the influence of the experimental parameters, like the absorbed energy, on thermal contrasts. Finally, a scheme to conduct full-scale test of a wind rotor blade in less than three hours is proposed. KW - Pulsed thermography KW - Wind rotor blade KW - GFRP PY - 2019 DO - https://doi.org/10.1016/j.compstruct.2019.02.027 SN - 0263-8223 VL - 215 SP - 60 EP - 68 PB - Elsevier CY - Amsterdam AN - OPUS4-47396 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -