A small wind power generator with Archimedes blades made of polypropylene has been developed for the effective generation of eco-friendly electronic energy. Despite the excellent structural characteristics of the higher performance of an Archimedes blade, its shape is complicated to manufacture, and presents difficulty in guaranteeing mechanical reliability in the outdoor operating environment. Especially, the UV-Light deterioration in a long-term of several years affects the mechanical properties of the polypropylene blade. To evaluate the change of strength depending on the amount of UV-Light irradiation in the outdoor environment, an accelerated UV-Light deterioration test is proposed and conducted using three types of blade materials, such as polypropylene with UV-Resistance material (C₂₀ H₂₅ N₃O) coated and mixed ones. Through the experimental tests, the UV resistant material coating on the blade showed the best properties for long-term exposure to UV light. Based on the test results of property changes, the Archimedes blade was analyzed using a finite element method to predict the reliability of the blade’s underused conditions. As a result of the analysis, the UV degradation resistance of Archimedes blades with UV coating improved by 2.4 times compared to the case without UV coating.

A conical roll-shaping process was proposed for fabrication of a metallic spiral blade applied to a small-scale wind turbine system. A spiral blade has continuously different curvatures, with a range of 100 to 350 ㎜ radius. To fabricate this complex shape, we developed a conical rollshaping process having two main conical rollers for feeding a blank sheet, and two cylindrical side rollers for control of local bending. For clear understanding of the process parameters, numerical analyses were conducted using a commercial code, Pam-Stamp. This study optimized the effects of process parameters, such as gap and angle between the main rollers and side rollers, and also the movement of side rollers. In order to increase the forming efficiency, a central rotation point was also calculated by the analytical approach. This developed rolling process can thus be utilized in a sheet metal forming process for obtaining spirally curved sheet metal shapes.