Parametric Structural Design of Vertical-Axis Tidal Turbine Arrays

Abstract

This thesis presents an approach for the structural design of vertical-axis tidal turbinearrays, including both the turbine blades and the supporting superstructure. Design load cases and performance goals are established in a Load and Resistance Factor Design (LRFD) framework. A simplified frame model is derived to efficiently perform a parametric study on blade structural performance using loads derived from hydrodynamic simulations. This model is compared to a higher resolution finite element model of the blade to identify ways in which the simplified model may underestimate stresses and deflections. A frame model is developed for the superstructure using loads derived from experimental hydrodynamic data. The design approach and component models are implemented in a parametric design algorithm which determines the required size of each structural component for a given set of flow, control, and geometric parameters. The parametric design algorithm is applied for a range of turbine conditions representative of potential sites and control strategies. Trends in the structural requirements, controlling limit states, and limits of feasibility are discussed.