Evaluation of Design Concepts for Adaptive Wind Turbine Blades

Abstract

Sandia is a rnuitiprcgram laboratory operated by Sandi Corporation.h k h e e d tdartin Campany. for the United States hpartmant of q n e r g y under Contract DE-AC04-WAL85OM);""~ Approved tor public release; firmer dissemination unlimited. Issued by b d i a AbstractThe objectives of this work were to develop conceptual structural designs for an adaptive (bend-twist coupled) blade, to evaluate candidate design concepts, to identify constraints and/or concerns for manufacturing, load paths, and stress concentrations, to develop estimates of structural performance and costs, and to select a single configuration as showing the greatest potential for success in manufacturing, strength and durability.This report summarizes the work performed on this project, including the approach taken, configurations and materials considered, and the computational methodology used. The work presented includes: 0Candidate fiber orientations and fabric architectures for adaptive blade manufacture are identified and assessed on the basis of estimated static strength, stiffness, and fabrication costs. 0A parametric study is performed for potential blade structural arrangements. Each configuration is evaluated on the basis of estimated manufacturing cost and magnitude of bend-twist coupling achieved. Based on the parametric study results, a single configuration is selected for hrther evaluation. A complete blade model is developed and assessed on the basis of estimated manufacturing cost and bend-twist behavior under steady loading.

Adaptive Bend-Torsional Coupling Wind Turbine Blade Design Imitating the Topology Structure of Natural Plant Leaves

“…Based on the blade FEM calculation method (McKittrick et al, 2001), the equations from (30) to (32) were used to calculate the coupling controlled factor and stiffness of each blade section (Griffin, 2002), whilst, If all the parameters of each section are used to evaluate the overall aerodynamic performances of the wind turbine blade, it is too complex and inconvenient to fulfill the evaluation. Literature (Wetzel, 2005) reported that the aerodynamic performances in the region closer to the blade tip are more important.…”

Large-Scale Offshore Wind Power in the United States: Assessment of Opportunities and Barriers

“…Concepts such as active variable diameter rotors, bend-twist coupled blades, two-bladed rotors, or active control surfaces could have a higher economic value offshore, as long as they can also contribute to higher reliability (Energy Unlimited 2006;TPI Composites 2003a;Griffin 2002). Structural loads caused by turbulence can be reduced using both passive and active controls to allow for longer blades and greater swept area, which can benefit both land-based and offshore turbines.…”

On the Design Synthesis of Multistable Equilibrium Systems

“…power rating and height) is logistical in terms of transporting the large and heavy parts and assembling them by crane. Thus, an adaptable turbine blade design has been proposed that does not need motors for pitch control, but can have bend-twist coupling as needed when the blades spin too quickly [Eisler and Veers, 1998;Griffin, 2002]. This causes the blades to extract less power from the wind due to the bending moments pitching the blade out of the wind.…”