Evaluation of the new B-REX fatigue testing system for multi-megawatt wind turbine blades : preprint /

The National Renewable Energy Laboratory (NREL) recently developed a new hybrid fatigue testing system called the Blade Resonance Excitation (B-REX) test system. The new system uses 65% less energy to test large wind turbine blades in half the time of NREL's dual-axis forced-displacement test m...

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Bibliographic Details
Main Author:	White, Darris
Corporate Author:	National Renewable Energy Laboratory (U.S.)
Other Authors:	Musial, Walter D., Engberg, Scott
Format:	Government Document Book
Language:	English
Published:	Golden, Colo. : National Renewable Energy Laboratory, [2004]
Series:	Conference paper ; NREL/CP-500-37075
Subjects:	Fatigue testing machines > Evaluation. Wind turbines > Testing. Turbines > Blades > Testing. 14 SOLAR ENERGY 17 WIND ENERGY ACCURACY EVALUATION EXCITATION HYDRAULICS NATIONAL RENEWABLE ENERGY LABORATORY OPERATING COST RESONANCE STRAINS TESTING WIND TURBINES
Online Access:	https://purl.fdlp.gov/GPO/LPS70753

Description
Summary:	The National Renewable Energy Laboratory (NREL) recently developed a new hybrid fatigue testing system called the Blade Resonance Excitation (B-REX) test system. The new system uses 65% less energy to test large wind turbine blades in half the time of NREL's dual-axis forced-displacement test method with lower equipment and operating costs. The B-REX is a dual-axis test system that combines resonance excitation with forced hydraulic loading to reduce the total test time required while representing the operating strains on the critical inboard blade stations more accurately than a single-axis test system. The analysis and testing required to fully implement the B-REX was significant. To control unanticipated blade motion and vibrations caused by dynamic coupling between the flap, lead-lag, and torsional directions, we needed to incorporate additional test hardware and control software. We evaluated the B-REX test system under stable operating conditions using a combination of various sensors. We then compared our results with results from the same blade, tested previously using NREL's dual-axis forced-displacement test method. Experimental results indicate that strain levels produced by the B-REX system accurately replicated the forced-displacement method. This paper describes the challenges we encountered while developing the new blade fatigue test system and the experimental results that validate its accuracy.
Item Description:	"December 2004." "To be presented at the 43rd AIAA Aerospace Sciences Meeting and Exhibit, Reno, Nevada, January 10-13, 2005." Title from title screen (viewed on June 8, 2006). Electronic resource.
Physical Description:	14 pages : digital, PDF file.
Format:	Mode of access: Internet from the NREL web site. Address as of 6/8/06: http://www.nrel.gov/docs/fy05osti/37075.pdf; current access available via PURL.