A METHOD BASED ON CLASSICAL LAMINATION THEORY TO CALCULATE STIFFNESS PROPERTIES OF CLOSED COMPOSITE SECTIONS

Abstract

Structural deformation of composite wind turbine blades affect the aerodynamic performance of the rotor. To design better blades in terms of efficiency, aerodynamic performance and load mitigation, it is crucial to understand how blades act under operational loads. An interdisciplinary research should be conducted including composite structures and aerodynamics to analyze this interaction. This article focuses on the structural part and explains an easy to apply method to define sectional properties of a closed composite section. The method is based on Classical Lamination Theory (CLT) and it is assumed that the blade is a thin walled structure. Stress concentration and warping effects are ignored. During preliminary design phase, this method is useful to calculate bending and torsional stiffness values based on different lamination parameters and materials, it can also be used to investigate bending-torsion coupling effects. This article also includes parametric studies on NACA profiles using the method explained. This is the first phase of a study investigating aero-structure interaction in wind turbine blades and its effects on rotor performance.

Keywords

• wind turbine blade
• composite section
• blade section stiffness
• coupling