TY - CONF A1 - Trappe, Volker A1 - Basan, Ricardo A1 - Grasse, Fabian ED - Paris, Federico T1 - Stiffness and fracture of shear loaded laminates with unidirectional and biaxial fibre orientation investigated with a picture frame test N2 - Fibre Reinforced Plastics (e.g. CFRP, GFRP) characteristically show nonlinear stress-strain behaviour due to intralaminar shear loading. The determination of the in-plane shear stiffness and strength for this class of material is difficult and common test standards and methods of analysis are partially inaccurate. The identification of the in-plane shear properties was made with an especial designed “picture frame test device” which enables shear loading up to 950N/mm. Therefore the strength limit can be reached at specimens with adequate thickness and a high safety factor against buckling. Due to the chosen design the maximum of the shear loading and the final failure occur in the centre of the specimen. The experiments match with the numerical analysis. T2 - ECCM16 - 16TH EUROPEAN CONFERENCE ON COMPOSITE MATERIALS CY - Seville, Spain DA - 22.06.2014 KW - Picture frame test KW - Fibre reinforced plastics (FRP) KW - Shear strength and stiffness KW - In-situ effect PY - 2014 SN - 978-84-616-9798-4 VL - 2014 SP - ID0263 - 1 EP - 8 PB - ECCM CY - Sevilla AN - OPUS4-37617 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Grasse, Fabian A1 - Trappe, Volker A1 - Thöns, Sebastian A1 - Said, Samir ED - De Roeck, G. ED - Degrande, G. ED - Lombaert, G. ED - Müller, G. T1 - Structural health monitoring of wind turbine blades by strain measurement and vibration analysis N2 - Wind turbine blades have to withstand a high number of load cycles in mostly hard weather conditions over 20 years. In a research project BAM and several partners have designed, evaluated and tested a condition monitoring system for all parts of a wind turbine. At a rotorblade with a length of 58 m fibre bragg grating sensors were applied for in-service strain measurement. Additionally a complex test rig was designed to enable real biaxial loading conditions at a representative test rotor blade to simulate the mechanical loading conditions in the lab. In this test blade with a length of 8 m also fibre bragg grating sensors were implemented to determine their influences for the structure and the condition monitoring system. Vibration measurements were carried out at different test phases. The results were compared with finite element strain and modal analysis. T2 - EURODYN 2011 - 8th International conference on structural dynamics CY - Leuven, Belgium DA - 04.07.2011 KW - Rotor blade KW - Test blade KW - Modal analysis KW - Condition monitoring PY - 2011 SN - 978-90-760-1931-4 IS - MS25 Tue SP - 3490 EP - 3497 AN - OPUS4-25076 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Grasse, Fabian A1 - Trappe, Volker A1 - Hickmann, Stefan A1 - Meister, O. T1 - Lifetime assessment for GFRP-gliders using a representative substructure N2 - In a research project fatigue tests on two identical wing sections that are used as representative substitute components were performed to estimate lifetime enhancement of light-weight aircraft such as general aviation gliders. Single step fatigue tests at limit load on one component were compared with spectrum loading on the other. A characteristic damage behaviour was observed. Local buckling due to high shear loading of the sandwich core of the wing shell causes the main damage. Even though an intentionally high load level was chosen no increase of micro-cracking could be detected. Additionally no delamination effects in laminates or bondings were observed except the skin-core delamination which causes the buckling effect in the wing shell due to fatigue loading. Finally the concept of using representative substructures and accompanying specimen tests is an effective approach for in-service loading investigations and could also be applied to research on wind turbine blades. KW - Glass fibre reinforced plastics (GFRP) KW - Grey scale value analysis KW - X-ray-refraction KW - Non-destructive testing (NDT) KW - Fatigue tests PY - 2010 U6 - https://doi.org/10.1016/j.ijfatigue.2009.02.003 SN - 0142-1123 VL - 32 IS - 1 SP - 94 EP - 99 PB - Elsevier CY - Oxford AN - OPUS4-20498 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Müller, Bernd R. A1 - Trappe, Volker A1 - Goebbels, Jürgen A1 - Hickmann, Stefan A1 - Grasse, Fabian T1 - Non-destructive characterization of composites: from small scale to complex component testing - a challenge T2 - International Symposium on NDT in Aerospace CY - Hamburg, Germany DA - 2010-11-22 KW - Aircraft KW - Wind turbine blades KW - Automotive KW - X-ray refraction KW - Fibre orientation KW - WAXS technique KW - X-ray computed tomography PY - 2010 SN - 978-3-940283-28-3 IS - DGZfP-BB 124 (Tu.2.B.1) SP - 1 EP - 6 AN - OPUS4-22724 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -