A simplified method for assessing wind-induced fatigue damage

Patel, Kaustubh; Freathy, Paul

doi:10.1016/0141-0296(84)90023-3

Cited by 13 publications

(6 citation statements)

References 0 publications

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“…The idea of approximate and fast fatigue damage estimation in the design phase of structures is not new, and simplified methods for assessing wind‐induced fatigue damage have already been used for buildings as well as for offshore structures some decades ago. More recent work on wind turbines has focused on the prediction of actual loading curves, e.g., in the study of Manuel and Veers , limited to a wind speed range between 15 and 19 m/s.…”

Section: Introductionsupporting

confidence: 88%

Simplified fatigue load assessment in offshore wind turbine structural analysis

Zwick

Muskulus

2015

Wind Energy

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The estimation of fatigue lifetime for an offshore wind turbine support structure requires a large number of time-domain simulations. It is an important question whether it is possible to reduce the number of load cases while retaining a high level of accuracy of the results. We present a novel method for simplified fatigue load assessments based on statistical regression models that estimate fatigue damage during power production. The main idea is to predict the total fatigue damage only and not also the individual damage values for each load case . We demonstrate the method for a jacket-type support structure. Reducing the number of simulated load cases from 21 to 3, the total fatigue damage estimate exhibited a maximum error of about 6% compared with the complete assessment. As a consequence, a significant amount of simulation time can be saved, in the order of a factor of seven. This quick fatigue assessment is especially interesting in the application of structural optimization, with a large number of iterations.

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Section: Introductionsupporting

confidence: 88%

Simplified fatigue load assessment in offshore wind turbine structural analysis

Zwick

Muskulus

2015

Wind Energy

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“…From ( 13), a maximum amplitude of 77.1 kN m due to alongwind and 58.9 kN m due to acrosswind loads is obtained, while a far smaller static alongwind base reaction moment My equal to 5.8 kN m is predicted using (6). This indicates that the effect of fluctuating wind actions on the tower stress/strain field is preponderant with respect to that exerted by the static alongwind action.…”

Section: Numerical Modelling Of the Wind Tower: Estimation Of The Bas...mentioning

confidence: 98%

“…Although many papers dealt in the past with wind-induced fatigue [6][7][8][9][10][11] and recently the Eurocode 1 [12] codified the first method to take it into account in the design of structures exposed to wind actions, the strength prediction of wind towers is difficult, for a number of reasons. First, because cracks can initiate at different points, including the base flange-to-column weld, the handhold detail and the anchor rods [3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Structural health monitoring of wind towers: remote damage detection using strain sensors

Benedetti¹,

Fontanari²,

Zonta³

2011

Smart Mater. Struct.

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Exploiting wind energy in complex sites like mountain terrains implies the necessity for remote structural health monitoring of the wind towers. In fact, such slender vertical structures exposed to wind may experience large vibrations and repeated stress cycles leading to fatigue cracking. Possible strategies for remote fatigue damage detection are investigated. Specifically, this paper is focused on the use of suitable strain sensors for crack detection in critical sites of the structure, suggesting several strategies taking into account the possibility of wind direction changes and/or wind calm phases. They are based on a radial arrangement of strain sensors around the tower periphery in the vicinity of the base weld joint. The most promising strategy uses the strain difference between adjacent strain sensors as an index of the presence of a crack. The number of sensors to be installed is dictated by the minimum crack size to be detected, which in turn depends on the expected extreme wind conditions and programmed inspection/repair schedule for the structure.

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“…(16), (19), (24) and (33) can be rewritten as: (41) in which it is proposed to assumeD = 0.22,L = 0.033.…”

Section: Closed Form Approximationsmentioning

confidence: 99%

“…Patel and Freathy [19] and Wyatt [20,21] adopted a time-domain approach and semi-empirical formulae to consider the combined effects of the quasi-static and resonant parts of the wind-induced response, assuming that the fatigue curve is a straight line on a log-log scale. Holmes [22] analyzed the alongwind-induced fatigue and derived two closed form solutions that represent, respectively, an upper and a lower bound of the mean total damage: the first was obtained representing the stress process as a narrow band; the second was related to the lower bound of the damage correction factor due to Wirshing and Light [23].…”

Section: Introductionmentioning

confidence: 99%