Equivalent beam modeling scheme based on three-dimensional structure with blade element concept

Abstract

The most important step in the design of wind turbine and blades is integrated load analysis, which is usually designed to describe a three-dimensional structure using a one-dimensional beam element; represents a three-dimensional blade with aerodynamic and structural information. In this regard, one-dimensional elements are required to accurately represent all the structural properties of a three-dimensional component. Most of the previous methods regarded the blade as a linear structure, resulting in limitations associated with nonlinearities. The geometry of the blades has a significant change along the length, and the composition of the materials used inside the blades is very complex, so these methods are not suitable for extracting the characteristics of the blades. In this paper, a new design scheme of a one-dimensional beam modeling method is proposed based on the blade sectional element concept that is easier and faster to apply without performing nonlinear analysis. In addition, the validation of the accuracy of its numerical analysis results, the total mass and modal analysis results are compared between three-dimensional blade and one-dimensional blade.

Keywords:

• wind turbine
• rotor blade
• extraction of blade properties
• equivalent beam model
• structural properties
• aero-elastic analysis
• blade element momentum theory (BEMT)

Nomenclature

$\mathit{X},\mathit{Y},\mathit{Z}$	=	X, Y, Z directions in global reference frame, respectively
$\mathit{x},\mathit{y},\mathit{z}$	=	x, y, z directions in local reference frame, respectively
$1,2,3$	=	Local reference frame of a single layer of FRP materials
$V_1,V_2,V_3$	=	Linear velocity for 1,2,3 direction
${\mathrm{\Omega }}_1,{\mathrm{\Omega }}_2,{\mathrm{\Omega }}_3$	=	Angular velocity for 1,2,3 direction
$M_x$	=	Edge-wise bending moment
$M_y$	=	Flap-wise bending moment
$M_z$	=	Blade bending moment
$F_x$	=	Flap-wise shear force
$F_y$	=	Edge-wise shear force
$F_z$	=	Span-wise (tensile) force
$\mathit{E}{I}_x$	=	Flap-wise stiffness
$\mathit{E}{I}_y$	=	Edge-wise stiffness
$\mathit{GJ}$	=	Torsional stiffness
$\mathit{EA}$	=	Extensional stiffness
$\mathit{MW}$	=	Megawatt

Disclosure statement

No potential conflict of interest was reported by the author.