Equivalent load profile development for fatigue testing of a 13-metre wind turbine blade
Kazemi Vanhari, Afrooz Fagan, Edward Jiang, Yadong Meier, Patrick Finnegan, William Goggins, Jamie
Kazemi Vanhari, Afrooz
Fagan, Edward
Jiang, Yadong
Meier, Patrick
Finnegan, William
Goggins, Jamie
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Publication Date
2020-08-01
Type
Downloads
Citation
Kazemi Vanhari, Afrooz, Fagan, Edward, Jiang, Yadong, Meier, Patrick, Finnegan, William, & Goggins, Jamie. (2020). Equivalent load profile development for fatigue testing of a 13-metre wind turbine blade Paper presented at the Civil Engineering Research in Ireland (CERI 2020), Cork, August.
Abstract
Since one of the most common problems with wind turbine blades is fatigue failure, full-scale fatigue testing is an effective way to validate the performance of a wind turbine blade. In this paper, the fatigue test loads in both edgewise and flatwise directions for a 13 metre wind turbine blade are derived, and used to determine an equivalent design life loading to apply in a fullscale fatigue test in the Large Structures Research Laboratory (LSRL) located in the Alice Perry Engineering Building, NUI Galway. The blade is constructed from glass-fibre reinforced powder epoxy composite material and consists of two internal shear webs. The blade is supported at its root on a frame constructed from S355 grade steel, and three hydraulic actuators (capacities range from 250 kN to 750 kN) work in concert to apply the flatwise and edgewise bending moment distribution along the blade. To develop the fatigue test load, aeroelastic simulation tools, including AeroDyn and FAST, are used to obtain the load time series under power producing, starting, stopping, and parking situations according to the International Electrotechnical Commission 61400-1 standard. The Rainflow counting method is used to extract the number of cycles for combinations of stress range and mean stress from the input load series. The Goodman method is employed for computing the number of permissible cycles for each combination of stress range and mean values and the Palmgren–Miner rule is applied for the cumulative damage calculation. For the operational load cases analysed, it was found that there was a negligible risk of fatigue damage for the unidirectional materials in the blade. The areas of the blade that showed a higher risk of fatigue were plies near the root of the blade, at the leading and trailing edges; however, the expected lifetime still exceeded the 20 year design life of the blade.
Publisher
Civil Engineering Research Association of Ireland
Publisher DOI
Rights
Attribution-NonCommercial-NoDerivatives 4.0 International