Structural mechanics for design of grouted connections in monopile wind turbine structures

Lotsberg, Inge

doi:10.1016/j.marstruc.2013.03.001

Cited by 70 publications

(29 citation statements)

References 7 publications

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“…The large magnitude bending loads on a GC result in high tensile stresses on the grout, which subsequently induces cracking in different directions. Furthermore, the ovalisation of the steel piles leads to a gap being formed at the steel grout interface [5]. As a result, the interface gaps lead to water ingress, which was also reported on some of the inspected monopiles [6].…”

Section: Introductionsupporting

confidence: 55%

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Non-linear finite element analysis of grouted connections for offshore monopile wind turbines

et al. 2019

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Section: Introductionsupporting

confidence: 55%

“…To investigate the interface behaviour of the numerical models the maximum gap opening at the bottom of the connection was determined for the maximum applied load. Thereinafter, the results are compared with the analytical model proposed in [5] which is described in equations 6 to 8. p =…”

Section: Shear Key Numbermentioning

confidence: 99%

Non-linear finite element analysis of grouted connections for offshore monopile wind turbines

et al. 2019

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“…Newer approaches are only available for monopiles (cf. [7,10]) but are not applicable for lattice substructures. Compared to oil and gas platforms wind turbine structures face significantly higher fatigue loads from wind and waves.…”

Section: Introductionmentioning

confidence: 99%

Impact of Water on the Fatigue Performance of Large-Scale Grouted Connection Tests

Schaumann

Raba

Bechtel

2016

Volume 6: Ocean Space Utilization; Ocean Renewable Energy

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Grouted connections represent a common joining technique between substructure and foundation piles of offshore oil & gas platforms as well as of offshore wind turbines. Due to cyclic loads arising from wind and wave actions the fatigue performance of the connection has to be considered. In lattice substructures like jackets the grouted connections are located at seabed level being fully submerged during their entire lifetime. Today’s fatigue design regulations are based on investigations neglecting any influence of the surrounding water since they were conducted in dry ambient conditions. So far, only Germanischer Lloyd gives additional recommendations for submerged grouted connections. At the Institute for Steel Construction, Leibniz Universität Hannover, Germany investigations of the joint research project ‘GROWup’ focus on the fatigue performance of axially loaded grouted connections. The project is funded by the Federal Ministry for Economic Affairs and Energy (BMWi, funding sign: 0325290) and is the third project in a row dealing with grouted connections. As part of this research project, cyclic loading tests on small-scale and large-scale grouted connections with shear keys are conducted. Small-scale fatigue tests showed a reduced number of endurable load cycles for connections when tested in wet ambient conditions. However, the transferability of these findings to a larger scale was still doubtful due to unknown scale effects. Therefore, the impact of water on the fatigue performance was tested recently at large-scale grouted connections. Previous to the submerged large-scale grouted connection fatigue tests, similar test specimens were exposed to alternating loads at dry ambient conditions. Comparison of both large-scale test results under wet and dry conditions enable to estimate the influence of water on the fatigue performance of grouted connections. Reflection of the small-scale test results gives hints on the scale effect. Test preparation, test results and design recommendations are presented in the paper.

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“…or to defects, malfunctions or failures in the components of the WT (e.g., braking system failure, or be struck by blade, etc.) [37,38]. The causes of failures (or root causes) of the components of a wind turbine can be summarized as follows [35,39]: structural (design fault, external damage, installation defect, maintenance fault, manufacturing defect, mechanical overload, mechanical overload-collision, mechanical overload-wind, presence of debris); wear (corrosion, excessive brush wear, fatigue, pipe puncture, vibration fatigue, overheating, insufficient lubrication); electrical (calibration error, connection failure, electrical overload, electrical short, insulation failure, lightning strike, loss of power input, conducting debris, software design fault).…”

Section: Fta For Wtsmentioning

confidence: 99%

Optimal Maintenance Management of Offshore Wind Farms

2016

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Abstract:Nowadays offshore wind energy is the renewable energy source with the highest growth. Offshore wind farms are composed of large and complex wind turbines, requiring a high level of reliability, availability, maintainability and safety (RAMS). Firms are employing robust remote condition monitoring systems in order to improve RAMS, considering the difficulty to access the wind farm. The main objective of this research work is to optimise the maintenance management of wind farms through the fault probability of each wind turbine. The probability has been calculated by Fault Tree Analysis (FTA) employing the Binary Decision Diagram (BDD) in order to reduce the computational cost. The fault tree presented in this paper has been designed and validated based on qualitative data from the literature and expert from important European collaborative research projects. The basic events of the fault tree have been prioritized employing the criticality method in order to use resources efficiently. Exogenous variables, e.g., weather conditions, have been also considered in this research work. The results provided by the dynamic probability of failure and the importance measures have been employed to develop a scheduled maintenance that contributes to improve the decision making and, consequently, to reduce the maintenance costs.

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Structural mechanics for design of grouted connections in monopile wind turbine structures

Cited by 70 publications

References 7 publications

Non-linear finite element analysis of grouted connections for offshore monopile wind turbines

Non-linear finite element analysis of grouted connections for offshore monopile wind turbines

Impact of Water on the Fatigue Performance of Large-Scale Grouted Connection Tests

Optimal Maintenance Management of Offshore Wind Farms

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