Nonlinear Stress Analysis of Vertical-Axis Wind Turbine Blades

Abstract

A Darrieus-type vertical-axis wind turbine has been proposed as an alternate to conventional horizontal axis, propeller-type machines. An advantage is that the blades will be primarily in tension, thus making for a more efficient design. In connection with its vertical-axis wind turbine program, Sandia Laboratories has developed the “troposkien” (Greek for turning rope) shape for the blade design. The prototype blade shape is similar to that of the troposkien, but more easily manufactured. The effect on the stress distribution of this alternate blade shape is investigated. Analytical models of the blades were constructed using a general purpose, nonlinear, dynamic finite element structural code. This code accounts for the large deflection effects of the various blade shapes through incremental applications of angular velocity.