10089_001.pdf - Load set calculation - ECN
10089_001.pdf - Load set calculation - ECN
10089_001.pdf - Load set calculation - ECN
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<strong>Load</strong> <strong>set</strong> <strong>calculation</strong> DOWEC 6MW H. Efdé<br />
4 Results<br />
After the PhatasIV <strong>calculation</strong>s the digital output files were converted in ASCI format with the Phatas<br />
postprocessor PHPOST.exe. PHPOST can convert 128 variables maximum per postprocessing run.<br />
Stentec B.V.’s post processor ADAP was used to generate extreme values tables, statistics and for<br />
fatigue analysis 1Hz equivalent signals. The extreme values were extracted from all load cases of<br />
the ulitmate and fatigue load <strong>set</strong>. For the fatigue analysis only load cases 12 a/b, 18a/b and 24a/b<br />
were examined. These are considered to be the decisive load cases for optimalisation.<br />
4.1 Maximum tower foot bending moment<br />
According IEC 6.1 36 simulations are performed with the wind turbine idling at a windspeed<br />
(stochastic model) of 41.5 m/s. Each load case is calculated with a different wind direction. To<br />
improve the idling of the model, the pitch angle of the blades is <strong>set</strong> at 85º.<br />
The maximum resulting tower foot bending moments are:<br />
Table 8: Ultimate tower foot bending moments<br />
Variable Extreme Ldcase 2 Ldcase 3 Ldcase 4 Ldcase<br />
Mxt[01] -177230 E50335 -158310 E50325 -155300 E50345 -139370 E50315<br />
Myt[01] 79498 E50025 -79262 E50175 -76273 E50185 -74108 E50195<br />
all values in kNm, load factor = 1.00<br />
The load case E50335 generates the highest tower foot bending moment. This load case is repeated<br />
8 times, but for each load case a different stochastic model is used. The maximum tower bending<br />
moments are:<br />
Table 9: Ultimate tower foot bending moments<br />
Variable 1 2 3 4 5 6 7 8<br />
Mxt[01] -177230 -170690 -166180 -147640 -146740 -135330 -133620 -117230<br />
Myt[01] 87609 85477 77240 73366 71669 67842 65646 53084<br />
all values in kNm, load factor ¡ = 1.00<br />
From these values it can be determined that the mean maximum tower foot bending moment<br />
Mxt[01] is: 149333 kNm.<br />
It has to be noted that this value is not the absolute highest value. When looking at the extreme<br />
values tables load case GrEog1Voc generates the highest tower foot bending moment Myt[01],<br />
which is -281560 kNm (with ¢ = 1.00) . For a plot of this loadcase see Appendix C.<br />
R45.04/01.03/03 Stentec, 3-1-03 page 11
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