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Examination, evaluation and repair of laminated wood blades after service on the Mod-OA wind turbineLaminated wood blades were designed, fabricated, and installed on a 200-KW wind turbine (Mod-OA). The machine uses a two-blade rotor with a diameter of 38.1 m (125 ft). Each blade weights less than 1361 kg (3000 lb). After operating in the field, two blade sets were returned for inspection. One set had been in Hawaii for 17 months (7844 hr of operation) and the other had been at Block Island, Rhode Island, for 26 months (22 months operating - 7564 hr). The Hawaii set was returned because of one of the studs that holds the blade to the hub had failed. This was found to be caused by a combination of improper installation and inadequate corrosion protection. No other problems were found. The broken stud (along with four others that were badly corroded) was replaced and the blades are now in storage. The Block Island set of blades was returned at the completion of the test program, but one blade was found to have developed a crack in the leading edge along the entire span. This crack was found to be the result of a manufacturing process problem but was not structurally critical. When a load-deflection test was conducted on the cracked blade, the response was identical to that measured before installation. In general, the laminate quality of both blade sets was excellent. No significant internal delamination or structural defects were found in any blade. The stud bonding process requires close tolerance control and adequate corrosion protection, but studs can be removed and replaced without major problems. Moisture content stabilization does not appear to be a problem, and laminated wood blades are satisfactory for long-term operation on Mod-OA wind turbines.
Document ID
Document Type
Conference Paper
Faddoul, J. R.
(NASA Lewis Research Center Cleveland, OH, United States)
Date Acquired
September 4, 2013
Publication Date
January 1, 1983
Subject Category
Energy Production And Conversion
Report/Patent Number
NAS 1.15:83483
Meeting Information
Meeting: Natl. Conf. of the American Wind Energy Association
Location: San Francisco, CA
Country: United States
Start Date: October 16, 1983
End Date: October 19, 1983
Accession Number
Funding Number(s)
PROJECT: RTOP 776-33-41
Distribution Limits
Work of the US Gov. Public Use Permitted.
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