Earthquake Response Modeling for a Parked and Operating Megawatt-Scale Wind Turbine

Prowell, Ian; Elgamal, Ahmed; Romanowitz, H.; DUGGAN, JIM; Jonkman, Jason

doi:10.2172/992345

Cited by 13 publications

(7 citation statements)

References 9 publications

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“…However, the influence of aerodynamic loads on the dynamic responses of wind turbines cannot be neglected, especially for wind turbines with large diameter rotors [23][24]. The combined effect of aerodynamic and seismic loadings should be included in the time domain analysis of wind turbines subjected to an earthquake event.…”

Section: Introductionmentioning

confidence: 99%

Analysis of seismic behaviour of an offshore wind turbine with a flexible foundation

Yang

Bashir

et al. 2019

Ocean Engineering

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Analysis of seismic behaviour of an offshore wind turbine with a flexible foundation http://researchonline.ljmu.ac.uk/id/eprint/10382/ Article LJMU has developed LJMU Research Online for users to access the research output of the University more effectively. , J (2019) Analysis of seismic behaviour of an offshore wind turbine with a flexible foundation. Ocean Engineering, 178. pp. 215-228. Abstract: This paper investigates the effects of nonlinear soil behaviours on the structural responses of offshore wind turbines (OWTs) subjected to wind, wave and earthquake loadings. A novel seismic analysis framework (SAF) is developed for the assessment of seismic behaviours of OWTs with flexible and fixed foundations. The SAF consists of an improved QuakeDyn module that is implemented into an open source tool (FAST). SAF has been validated through benchmark studies using numerical tools and the results show good agreements. Fully coupled nonlinear simulations have been performed for OWTs with fixed and flexible foundations under operational, parked and emergency shutdown states. The flexible foundation is modelled using nonlinear p-y curves obtained using LPILE. For all the examined operating conditions, notable differences of magnitude and variation in the responses between the flexible and fixed cases are observed, indicating the need for soil effects to be accounted in seismic behaviour analysis of wind turbines. It is further observed that the earthquake induces more severe vibrations on wind turbines with a flexible foundation compared to the one with a fixed base. Also, aerodynamic damping dissipates more energy from earthquake excitation resulting in a smaller tower-top fore-aft displacement. The shutdown triggered by the earthquake causes a 34% increase in the mudline bending moment for the flexible foundation case, while a decreasing trend is observed for the fixed foundation model. Similar observations are made  Corresponding author: lichun_usst@163.com 2 / 41regarding the tower-top displacements. The observations imply that ignoring the soil effect may lead to misjudgement of the consequence of an emergency shutdown. The relative orientation of the ground motion with respect to the wind direction causes significant difference in the seismic behaviour of the wind turbine. This confirms that it is necessary to interchange the horizontal components of an earthquake in order to consider the intersectional effect between ground motion and wind.

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Section: Introductionmentioning

confidence: 99%

Analysis of seismic behaviour of an offshore wind turbine with a flexible foundation

Yang

Bashir

et al. 2019

Ocean Engineering

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“…On the basis of this simplification, Zhao and Maisser and Sapountzakis et al used a multibody dynamic method for assessing the behavior of wind turbines under seismic excitation more effectively. However, aerodynamic loads play an important role on the dynamic behavior of towers of wind turbines especially for the case of large diameter wind turbines . The interaction between aerodynamic and earthquake loads should be accounted for the estimation of the response of wind turbines under an earthquake event.…”

Section: Introductionmentioning

confidence: 99%

Dynamic behavior of wind turbines influenced by aerodynamic damping and earthquake intensity

Yang

Kehua

et al. 2018

Wind Energy

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In the present paper the effects of aerodynamic damping and earthquake loads on the dynamic response of flexible-based wind turbines are studied. A numerical analysis framework (NAF) is developed and applied. NAF is based on a user-compiled module that is developed for the purposes of the present paper and is fully coupled with an open source tool. The accuracy of the developed NAF is validated through comparisons with predictions that are calculated with the use of different numerical analysis methods and tools. The results indicate that the presence of the aerodynamic loads due to the reduction of the maximum displacement of the tower attributed to the dissipation of earthquake excitation energy in fore-aft direction. Emergency shutdown triggered by strong earthquakes results to a rapid change of aerodynamic damping, resulting to short-term instability of the wind turbine. After shutdown of the wind turbine, enhanced dynamic response is observed. For the case where the wind turbine is parked, the maxima displacement and acceleration of tower-top increase linearly with the peak ground acceleration. With the use of the least-square method a dimensionless slope of tower-top displacements is presented representing the seismic response coefficient of tower that can be used to estimate the tower-top acceleration demand. Moreover, on the basis of the seismic response coefficient, an improved model for the evaluation of load design demand is proposed. This model can provide accurate predictions. KEYWORDS aerodynamic damping, dynamic behavior, earthquake intensity, seismic demand, wind turbines | INTRODUCTIONWind energy technology has a leading role in the renewable energy sector. 23.4 GW of new installed capacity of wind turbines that was added in China 1 for 2016; this value corresponds to the 42.8% of the overall added capacity globally for the same year. New installed wind farms are located along the northwest and southeast coasts of China. These wind farms are located in earthquake prone areas, close to the Eurasian and Pacific seismic belts. Wind farms that are located in the aforementioned areas are susceptible to damage on the event of an earthquake.Over the past decades it has been well accepted that earthquakes have a significant effect on the structural dynamic response of wind turbines. 2 Response spectrum method and finite element method (FEM) have been commonly used for the estimation of the seismic load demand of wind turbines. 3 With the use of the response spectrum method the rotor and nacelle are modeled as point lumped masses at tower-top. The seismic load demand of wind turbines can be calculated on the basis of the natural periods, mode shapes, and mass distribution of the tower. 4,5 Usually the aerodynamic damping and higher-order modes are neglected because of the overestimation of the seismic load demand. On the basis of experiments, 6 it is concluded that the seismic excitation increases significantly the lateral displacement of tower-top. On the other hand FEM is applied for the analysis of win...

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“…To better investigate the seismic behavior of wind turbine, the model needs to be improved by including structural stiffness and damping ratio and tested under various seismic excitations with different amplitude and frequency (Bazeos et al 2002). In addition, the factor that whether the wind turbine is operating or parked might influence the responses of wind turbine under earthquake loading (Prowell et al 2010). …”

Section: Fig 7 Comparison Of Accelerations A3 Recorded In the Towermentioning

confidence: 99%

Seismic Behavior of Offshore Wind Turbine with Suction Caisson Foundation

Zeng

Lian

2014

Geo-Congress 2014 Technical Papers

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Offshore wind energy plays a major role in the long-term goal of relying on renewable energy. The demand for offshore wind energy is increasing rapidly in the world. However, the construction of offshore wind farm in seismic active areas has strict requirements for the foundation selection and design. In this study, a group of earthquake centrifuge tests was performed on the wind turbine models with suction caisson foundation in order to evaluate the resistance to earthquake loading. The results showed that the seismic induced lateral displacement and settlement of offshore wind turbine foundation can be mitigated by increasing the caisson diameter, skirt length, and weight of the foundation.

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Earthquake Response Modeling for a Parked and Operating Megawatt-Scale Wind Turbine

Cited by 13 publications

References 9 publications

Analysis of seismic behaviour of an offshore wind turbine with a flexible foundation

Analysis of seismic behaviour of an offshore wind turbine with a flexible foundation

Dynamic behavior of wind turbines influenced by aerodynamic damping and earthquake intensity

Seismic Behavior of Offshore Wind Turbine with Suction Caisson Foundation

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