Three 9 m carbon fiber wind turbine blades have been designed through a research program initiated by Sandia National Laboratories. The individual designs feature such innovations as carbon spar caps, material-induced twist-bend coupling, and flatback airfoils, among others. All blades were constructed with conventional dry lay-up and VARTM infusion processes. Static tests of these blades were conducted at the National Wind Technology Center. The blades were subjected to flapwise loading to simulate the extreme wind loads expected for each design in a Class 2b wind site. The blades were loaded with a three-point whiffle-tree arrangement. Upon obtaining the predetermined test load, the blades were subsequently loaded to failure. Load, deflection, strain, and acoustic emissions were monitored throughout the experiments. All blades survived the specified test loads, with two designs exceeding it significantly. In addition, carbon strains of over 0.8% in both tension and compression were recorded in one of the tests. Finally, acoustic microphones were able to detect areas where damage was occurring, and indicated the beginnings of failure. This paper outlines the results of the structural tests that were conducted. Nomenclature VARTM = Vacuum Assisted Resin Transfer Method SNL = Sandia National Laboratories NWTC = National Wind Technology Center HP = High Pressure LP = Low Pressure

A novel bidirectional thickness profilometer based on transmission densitometry was designed to measure the localized thickness of semitransparent films on a dynamic manufacturing line. The densitometer model shows that, for materials with extinction coefficients between 0.3 and 2.9?D/mm, 100-500microm measurements can be recorded with less than +/-5% error at more than 10,000 locations in real time. As a demonstration application, the thickness profiles of 75mmx100?mm regions of polymer electrolyte membrane (PEM) were determined by converting the optical density of the sample to thickness with the Beer-Lambert law. The PEM extinction coefficient was determined to be 1.4D/mm, with an average thickness error of 4.7%.

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