TY - CONF A1 - Ghafafian, Carineh A1 - Popiela, Bartosz A1 - Nielow, Dustin A1 - Trappe, Volker T1 - Restoration of structural integrity – a comparison of various repair concepts for wind turbine rotor blade shells T2 - SMAR 2019 - 5th International Conference on Smart Monitoring, Assessment and Rehabilitation of Civil Structures (conference proceedings) N2 - Localized patches are a cost- and time-effective method for repairing fiber-reinforced polymer (FRP) sandwich wind turbine rotor blade shells. To increase the understanding of their effect on the fatigue of the blades, this study examines the effect of various layup methods of localized repair patches on the structural integrity of composite sandwich structures. Manufactured with the vacuum-assisted resin infusion (VARI) process, the shell test specimens are produced as a curved structure with glass fiber reinforced polymer (GFRP) sandwiching a polyvinyl chloride (PVC) foam core. Patch repairs are then introduced with varying layup techniques, and material properties are examined with cyclic fatigue tests. The transition region between patch and parent material is studied in greater detail with finite element method (FEM) simulations, with a focus on the effect of fiber orientation mismatch. Damage onset, crack development, and eventual failure are monitored with in-situ non-destructive testing methods to develop a robust understanding of the effects of repair concepts on material stiffness and strength. T2 - SMAR 2019 - 5th International Conference on Smart Monitoring, Assessment and Rehabilitation of Civil Structures CY - Potsdam, Germany DA - 27.08.2019 KW - Lightweight materials KW - Glass fiber reinforced polymers KW - Sandwich KW - Wind turbine blades PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-482170 SP - 1 EP - 8 PB - German Society for Non-Destructive Testing (DGZfP e.V.) AN - OPUS4-48217 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Trappe, Volker A1 - Nielow, Dustin T1 - Fatigue loading of sandwich shell test specimens with simulated production imperfections and in-situ NDT T2 - 7. International Conference on Fatigue of Composites Vicenza N2 - A shell test bench was developed at BAM 5.3 which allows for static and fatigue testing of curved fiber-reinforced plastic (FRP) structures, during which in-situ the damage state can be non-destructively inspected by thermography and strain-field measurement techniques. Sandwich shell specimens with typical wind turbine blade manufacturing defects were designed and tested. The tested imperfections show a fairly significant reduction (up to 90%) of the shell test specimens‘ lifetime, depending on the type of imperfection. Using the in-situ NDT methods incorporated in the shell test bench, the location and cycle time of the initial defects and the damage evolution was investigated. T2 - 7. International Conference on Fatigue of Composites CY - Vicenza, Italy DA - 04.06.2018 KW - Fatigue of sandwich shell structures KW - Non-destructive testing KW - Wind turbine blades PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-501275 SP - 1 EP - 7 AN - OPUS4-50127 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -