文档介绍：Journal of Wind Engineering
and Industrial Aerodynamics 90 (2002) 961–986
Optimal frequency design of wind turbine blades
Karam Y. Maalawia,*, Hani M. Negmb
a Mechanical Engineering Department, National Research Center, Tahrir Street, Dokki,
. Box 12622, Cairo, Egypt
b Aerospace Engineering Department, Cairo University, Giza, Egypt
Received 10 January 2001; received in revised form 25 January 2002; accepted 9 April 2002
Abstract
An optimization model for the design of a typical blade structure of horizontal-axis wind
turbines is presented. The main spar is represented by thin-walled tubular posed
of uniform segments each of which has different cross-sectional properties and length. qThe
optimization variables are chosen to be the cross-sectional area, radius of gyration and length
of each segment. The optimal design is pursued with respect to maximum frequency design
criterion. Global optimality is attainable by the proposed model and a novel mathematical
concept is given for placing the system frequencies. The problem is formulated as a non-linear
mathematical programming problem solved by multi-dimensional search techniques.
Structural analysis is restricted to the case of uncoupled flapping motion of the rotating
blade, where an exact method of solution is given for calculating the natural vibration
characteristics. Aeroelastic stability boundaries and steady-state response are calculated
using Floquet’s transition matrix theory. The results show that the approach used in this
study is efficient and produces improved designs pared with a reference or baseline
design. r 2002 Elsevier Science Ltd. All rights reserved.
Keywords: Wind power systems; Wind turbines; Blade dynamics and aeroelasticity; Structural optimization
1. Introduction
The design of a wind turbine structure involves many considerations such as
strength, stability, cost and vibration. Reduction of vibration is a good measure for a
essful design of blade structure.