State‐of‐the‐art framework for design of offshore wind jacket foundations

Nielsen, Martin Bjerre; Jensen, Jørgen Juncher; Harper, Christopher; Knudsen, Lennart Skovbjerg; Pedersen, Ronnie

doi:10.1002/stco.201900016

Cited by 4 publications

(2 citation statements)

References 12 publications

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“…We simulate a numerical model of a 7 MW jacket-supported turbine using the procedure outlined by Nielsen et al [57] and applied by, e.g., Augustyn et al [34]. The simulation procedure consists of the following steps: (1) the substructure model and corresponding wave loading are reduced to a Craig-Bampton superelement [58] with 30 internal modes accounting for internal substructure dynamics.…”

Section: Modelingmentioning

confidence: 99%

Reliability Updating of Offshore Wind Substructures by Use of Digital Twin Information

2021

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This paper presents a probabilistic framework for updating the structural reliability of offshore wind turbine substructures based on digital twin information. In particular, the information obtained from digital twins is used to quantify and update the uncertainties associated with the structural dynamics and load modeling parameters in fatigue damage accumulation. The updated uncertainties are included in a probabilistic model for fatigue damage accumulation used to update the structural reliability. The updated reliability can be used as input to optimize decision models for operation and maintenance of existing structures and design of new structures. The framework is exemplified based on two numerical case studies with a representative offshore wind turbine and information acquired from previously established digital twins. In this context, the effect of updating soil stiffness and wave loading, which constitute two highly uncertain and sensitive parameters, is investigated. It is found that updating the soil stiffness significantly affects the reliability of the joints close to the mudline, while updating the wave loading significantly affects the reliability of the joints localized in the splash zone. The increased uncertainty related to virtual sensing, which is employed to update wave loading, reduces structural reliability.

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Section: Modelingmentioning

confidence: 99%

Reliability Updating of Offshore Wind Substructures by Use of Digital Twin Information

2021

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“…The load iteration setup [25] depicted in Figure 5 is used to produce the required structural load input and response output. The setup includes the following four steps:…”

Section: Load Iteration and Response Simulationmentioning

confidence: 99%

Closed-loop updating of wind turbine models using blade pitch excitation

Schwarz-Wolf¹,

Ulriksen²,

Augustyn³

et al. 2021

Preprint

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Structural monitoring of wind turbines often involves the use of a numerical model, which must be regularly updated to yield an adequate representation of the governing dynamics. The model updating can be cast as an inverse problem, in which selected model parameters are estimated by minimizing the discrepancy between experimental target poles and model-predicted ones. An issue that may prevail in this setting is that the problem will be ill-posed, because the number of model parameters to be updated exceeds the number of target poles. The noted issue can be remedied by a virtual implementation of output feedback, which allows for computation of multiple closed-loop (CL) eigenstructures through non-linear transformations of the open-loop transfer matrix. The present paper offers an application study, in which virtual output feedback is used for updating numerical wind turbine models based on CL system poles. In particular, we explore the feasibility of employing the excitation stemming from the blade pitch control system as the input in the open-loop input-output realization required in the virtual output feedback. The methodological concept is outlined, and subsequently the applicability of the procedure is tested numerically in the context of simulations with a finite element model of a parked wind turbine. The preliminary findings suggest that procedures for customizing the pitch excitation to yield sufficient system excitation are required for the CL model updating to be feasible.

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