Improved Joints Based on 3D Fiber Architecture Preforms

Wind blades are a significant part of the installation and operating costs of wind turbines used for electricity generation. In the manufacture of wind blades, several composite elements must be joined; the joints between these elements present one of the most difficult aspects of their construction. Current practices are hand-labor intensive and result in thick bond lines. In turn, these practices lead to manufacturing defects and too often to premature failure of the wind blades. Pi joints, which are shaped like the Greek letter p and based on three-dimensional (3-D) fiber architectures, have been shown to increase joint strength in carbon composite aircraft structures and in glass composite naval structures by more than two fold. This project will develop technology for replacing current structures with Pi and ¿Y¿ joints based on 3-D fiber architectures. Commercial Applications and other Benefits as described by the awardee:The technology not only would lead to stronger wind turbine joints but also to a more robust, less costly manufacturing process. Installation costs of the turbines would be reduced by the lower cost wind blades, and operating costs would be reduced by the lower number of wind blade failures