Efficient response recovery procedures for detailed design of jacket foundations

Nielsen, Martin Bjerre; Jensen, Jørgen Juncher; Augustyn, Dawid Jakub; Pedersen, Ronnie

doi:10.1201/9781315641645-341

Cited by 7 publications

(10 citation statements)

References 1 publication

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“…The procedure is validated in numerous publications such as (7) and (8). In particular, it is illustrated that a force-controlled dynamic recovery-run yields highly accurate results as long as the superelement accurately represents the spectral properties of the underlying foundation model and thereby its interaction with the superstructure.…”

Section: Integrated Load Calculationsmentioning

confidence: 97%

State‐of‐the‐Art Framework for Structural Design of Offshore Wind Jacket Foundations

et al. 2019

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A state-of-the-art framework for design of jacket foundations for offshore wind turbines is presented. It is illustrated how an efficient, yet highly accurate structural model can be achieved by a combination of a comprehensive beam finite element model and more detailed shell/solid finite element models, where the former suffices for representing the overall global behaviour, while the latter improve the representation of non-trivial structural details such as the transition piece and tubular joints. Hereby the verification of the majority of the structural elements according to various design codes can be automated on beam element level, while the fatigue performance via the hot-spot method as well as detailed stress and buckling analysis for relevant joints and details can be performed based on the detailed shell/solid finite element models readily available for stiffness representation. This computational framework ensures consistency between the local and global description levels and an efficient cloud interface facilitates the thousands of design load cases that typically requires consideration for a full detailed design to be simulated within a reasonable amount of time.

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Section: Integrated Load Calculationsmentioning

confidence: 97%

State‐of‐the‐Art Framework for Structural Design of Offshore Wind Jacket Foundations

et al. 2019

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“…However, providing that a proper reduction method is used, the error is negligible as confirmed e.g. by Nielsen et al [4]. The second violation is introduced if the foundation designer performs structural changes to the jacket subsequent to the aero-elastic calculations.…”

Section: Introductionmentioning

confidence: 93%

“…The first violation of the assumption (reduced foundation model) is fairly well investigated by scientific community as well as the industry [2][3][4]9]. However, hardly any publications exist on the inconsistency of the interface forces and its influence on the foundation design.…”

Section: Introductionmentioning

confidence: 99%

17.04: Design of offshore wind turbine jacket foundations: On the influence of subsequent modifications on fatigue performance

2017

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The design of jacket foundations for offshore wind turbine typically relies on design loads from an integrated aero-elastic model of the full turbine structure and a reduced (superelement) representation of the foundation. In this paper the influence of introducing subsequent design changes to the foundation that potentially invalidate the design loads is studied based on a generic jacket foundation subject to combined wind and wave loading. The fatigue performance is considered for the reference case as well as a number of structurally modified configurations covering changes in braces, legs, soil conditions and footprint. The modified jackets are examined for both inconsistent design loads based on the reference geometry and updated loads associated with a consistent, aero-elastic load iteration with the updated geometry and/or soil conditions. Ratios between the fatigue lives based on the inconsistent and the updated forces are presented, indicating whether an additional load iteration is essential or not. By having an overall understanding of allowable structural modifications a foundation designer is able to provide a more efficient jacket design by independently optimizing the structure in the post-processing stage.It is shown that the subsequent jacket modifications may significantly affect the quality of the fatigue results. Some modifications, especially the ones associated with the boundary conditions, e.g. soil modifications significantly modify the global dynamic behaviour, thus indisputably require an additional aero-elastic load iteration. On the other hand, modifications resulting solely in local changes such as minor brace or leg size modifications, especially when increasing the stiffness, may be allowed in the post-processing phase without committing a significant error.

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“…In practice, however, the foundation is typically represented via a superelement, which is an approximation of its dynamic representation. However, as long as properly spectrally/spatially converged superelements are used, the difference is negligible when a dynamic force-controlled recovery run is performed, as illustrated in [11] and [12], for instance.…”

Section: Fe Models Of Details For Stiffness Representationmentioning

confidence: 99%

“…The procedure has been validated in numerous publications, e.g. [11] and [12], yet a brief theoretical argumentation of the consistency is summarized here. In a typical FE representation of the integrated model, the foundation and tower base share a common node at the interface elevation, hence the interface reactions are exchanged as internal (section) forces and do not appear explicitly.…”

Section: Fe Models Of Details For Stiffness Representationmentioning

confidence: 99%

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

et al. 2019

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Nominated for the Bernt Johansson Outstanding Paper Awards at Nordic Steel 2019 A state‐of‐the‐art framework for the design of jacket foundations for offshore wind turbines is presented here. The article illustrates how an efficient, yet highly accurate, structural model can be achieved through a combination of a comprehensive beam finite element model and detailed shell/solid finite element models, where the former suffices for representing the overall global behaviour and the latter improves the representation of non‐trivial structural details such as the transition piece and tubular joints. This approach allows the verification of standard structural elements according to various design codes to be automated on beam element level, while the fatigue performance via the hot‐spot method as well as detailed stress and buckling analyses of relevant joints and details can be performed based on the detailed shell/solid finite element models readily available for stiffness representation. The computational framework ensures full consistency between the local and global description levels and an efficient cloud interface facilitates the thousands of design load cases that typically require consideration in order that a full detailed design can be simulated within a reasonable timeframe.

show abstract

Efficient response recovery procedures for detailed design of jacket foundations

Cited by 7 publications

References 1 publication

State‐of‐the‐Art Framework for Structural Design of Offshore Wind Jacket Foundations

State‐of‐the‐Art Framework for Structural Design of Offshore Wind Jacket Foundations

17.04: Design of offshore wind turbine jacket foundations: On the influence of subsequent modifications on fatigue performance

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

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