Fatigue Life Evaluation of Wind Turbine Tower Based on Measured Data

Table 6

Annual total damage matrix based on average hourly damage [−log(D)].

Wind direction	Wind speed (m/s)									Dave
	0–3	3–5	5–7	7–9	9–11	11–13	13–15	15–17	17–19
N	10.23	6.01	4.41	4.35	4.17	3.86	3.94	5.08	7.91	5.55
NNE	5.98	4.65	4.94	4.89	4.55	4.47	4.47	8.42	5.49	5.32
ENE	4.79	5.12	5.48	4.96	5.20	5.60	5.19	5.19	5.31	5.20
E	6.35	6.40	5.73	5.29	5.60	—	—	—	—	5.87
ESE	6.45	5.79	4.04	4.28	4.75	5.33	—	—	—	5.11
SSE	6.47	6.37	5.30	4.99	4.96	4.94	5.55	—	—	5.51
S	6.49	5.80	5.23	5.10	5.13	4.14	4.92	5.19	—	5.25
SSW	6.77	5.36	4.93	4.56	4.45	4.48	4.86	5.79	—	5.15
WSW	6.06	6.02	5.04	5.20	5.31	4.89	4.24	4.83	5.31	5.21
W	7.00	5.86	5.26	5.64	4.77	4.73	4.71	5.31	—	5.41
WNW	7.11	5.41	5.41	4.56	4.39	4.63	5.09	—	—	5.23
NNW	6.83	5.21	4.62	3.87	3.75	3.94	4.43	4.94	—	4.70
Dave	6.71	5.67	5.03	4.81	4.75	4.64	4.74	5.59	6.00