Fatigue Life Evaluation of Wind Turbine Tower Based on Measured Data

Table 4

Damage matrix corresponding to 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	12.46	8.40	6.87	6.76	6.39	5.89	5.63	6.27	8.55	7.47
NNE	8.21	6.90	7.03	6.78	6.47	6.12	5.64	9.26	5.73	6.90
ENE	6.88	7.16	7.38	6.56	6.55	6.14	5.73	5.73	5.73	6.43
E	8.34	8.22	7.09	6.41	6.15	5.78	5.49	—	—	6.78
ESE	8.54	7.91	5.73	5.73	5.73	5.88	—	—	—	6.59
SSE	8.73	8.72	7.20	6.24	6.18	5.73	5.49	—	—	6.90
S	8.76	8.22	7.48	7.13	6.78	5.69	5.57	5.73	—	6.92
SSW	9.19	7.80	7.38	6.72	6.19	5.80	5.70	5.73	—	6.82
WSW	8.43	8.22	7.32	7.26	7.14	6.38	5.50	5.73	5.73	6.86
W	9.37	8.09	7.49	7.68	6.39	5.84	5.73	5.73	—	7.04
WNW	9.32	7.69	7.73	6.42	5.86	5.57	5.73	—	—	6.90
NNW	9.04	7.58	7.10	6.22	5.96	5.77	5.73	5.73	—	6.64
Dave	8.94	7.91	7.15	6.66	6.32	5.88	5.63	6.24	6.44