Linear modal analysis of a horizontal-axis wind turbine blade

Gizem Acar, Brian F. Feeny

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

2 Scopus citations

Abstract

In this work, mode shapes and modal frequencies of a horizontal axis wind turbine blade are found. The blade is modeled as a pre-twisted beam under bend-bend-twist deformations, and the strain, gravitational potential and kinetic energy expressions are found. These expressions are then simplified for linear theory, and further by using the assumed modes method in which assumed modes are chosen independently for flapwise, edgewise, and twist deflections from a cantilevered uniform beam. Lagrange’s equations of motion are applied to the assumed modal coordinates, and coupled linear equations are thus found. Modal analysis is applied to the assumed modal equations to find the resonance frequencies, and the resulting mode shapes are recombined to express the mode shapes in the bend-bend-twist coordinates. The approach was applied to a uniform twisted rectangular beam, and the first three mode shapes are found to be combinations of the inplane and out-of-plane bending. The results of the modal analysis are compared with results from a finite element analysis, and the mode shapes and frequencies are consistent. The method is also applied to NREL’s 5 MW wind turbine blade to find its bend-bend-twist mode shapes and natural frequencies.

Original languageEnglish
Title of host publicationExperimental and Applied Mechanics - Proceedings of the 2014 Annual Conference on Experimental and Applied Mechanics
EditorsNancy Sottos, Robert Rowlands, Kathryn Dannemann
Pages125-131
Number of pages7
ISBN (Electronic)9783319069883
DOIs
StatePublished - 2015
Event2014 SEM Annual Conference and Exposition on Experimental and Applied Mechanics, 2014 - Greenville, United States
Duration: 2 Jun 20145 Jun 2014

Publication series

NameConference Proceedings of the Society for Experimental Mechanics Series
Volume6
ISSN (Print)2191-5644
ISSN (Electronic)2191-5652

Conference

Conference2014 SEM Annual Conference and Exposition on Experimental and Applied Mechanics, 2014
Country/TerritoryUnited States
CityGreenville
Period2/06/145/06/14

Keywords

  • Assumed modes
  • Bend-bend-twist coupled vibrations
  • Finite element analysis
  • Position dependent modal properties
  • Wind turbines

Fingerprint

Dive into the research topics of 'Linear modal analysis of a horizontal-axis wind turbine blade'. Together they form a unique fingerprint.

Cite this