Today a large-scale wind turbine blade can be 70 m long and 5 m in root chord length, and it is fabricated in a single piece. This feature leads to high initial costs, as transportation of a large blade requires special trucks, escorts, and road adaptations. These constraints can account for approximately 6–7% of the total investment for the blade. In addition, the manufacturing process commonly used is a hand lay-up configuration of thermoset composite sheets. These materials are not reusable after fabrication, which is a non-renewable feature of existing systems. The project consists of manufacturing thermoplastic composite blades in segments, which are joined before installation at the turbine site. This paper addresses the preliminary research results when conducting design and fabrication of a small blade with this innovative approach. Three segmented blades are manufactured for a horizontal-axis wind turbine, with each blade having a 50 cm span and a 4 cm tip chord length. The blade size and profile are designed based on the idealized Betz limit condition. The material used for manufacturing is a glass fiber reinforced thermoplastic composite system with a polypropylene matrix that melts at 200 °C. Each blade is fabricated in 4 independently manufactured pieces, consisting of top/bottom, and tip/root segments, via a vacuum assisted thermoforming technique. The parts will be assembled afterwards by a joining process, forming the final part for site testing.
Vibration analysis for large-scale wind turbine blade bearing fault detection with an empirical wavelet thresholding method
