TY - JOUR

T1 - Monitoring of suction bucket jackets for offshore wind turbines

T2 - Dynamic load bearing behaviour and modelling

AU - Penner, Nikolai

AU - Grießmann, Tanja

AU - Rolfes, Raimund

N1 - Funding information: We would like to thank the Federal Ministry for Economic Affairs and Energy (BMWi) for funding, the Project Management Julich (PtJ) as well as our research partners at the Institute for Geotechnical Engineering (IGtH) in Hannover (Germany), the Bundesanstalt f?r Materialforschung und -pr?fung (BAM) in Berlin (Germany) and the company DONG Energy (Orsted). Further information on the research project can be found in the technical report [1]. We would like to thank the Federal Ministry for Economic Affairs and Energy (BMWi) for funding, the Project Management Julich (PtJ) as well as our research partners at the Institute for Geotechnical Engineering (IGtH) in Hannover (Germany), the Bundesanstalt für Materialforschung und -prüfung (BAM) in Berlin (Germany) and the company DONG Energy (Orsted). Further information on the research project can be found in the technical report [ 1 ].

PY - 2020/7

Y1 - 2020/7

N2 - Suction bucket foundations for offshore wind turbines (OWT) have considerable advantages compared to conventional foundation types: Due to the installation process with dead weight and applied negative pressure, noise from pile driving can be completely avoided. In addition, the installation process of the whole substructure, consisting of the buckets connected to the jacket, can be carried out in one work step, which increases efficiency. A prototype of the suction bucket jacket was installed in the wind park ‘Borkum Riffgrund 1’ (North Sea) in August 2014. Due to the pre-installed and comprehensive measuring system, it was possible to monitor all installation and operating phases. The data analysis of a storm event show an amplitude and frequency-dependent behaviour of the soil stiffness and the suction bucket foundation without wind turbine. In the frequency range of the first and second eigenfrequency (0.2 Hz < f < 5 Hz), the system behaves linearly. Here, the Frequency Domain Decomposition is used for identification and monitoring. For the lower frequency band (0.05 Hz < f < 0.2 Hz) where higher forces and displacements occur, a non-linear multilayer perceptron is chosen to model the non-linear relations between measurements. By applying two mathematical models for the relevant frequency ranges, all the information from the measurement data can be used for system identification and novelty detection under varying environmental conditions.

AB - Suction bucket foundations for offshore wind turbines (OWT) have considerable advantages compared to conventional foundation types: Due to the installation process with dead weight and applied negative pressure, noise from pile driving can be completely avoided. In addition, the installation process of the whole substructure, consisting of the buckets connected to the jacket, can be carried out in one work step, which increases efficiency. A prototype of the suction bucket jacket was installed in the wind park ‘Borkum Riffgrund 1’ (North Sea) in August 2014. Due to the pre-installed and comprehensive measuring system, it was possible to monitor all installation and operating phases. The data analysis of a storm event show an amplitude and frequency-dependent behaviour of the soil stiffness and the suction bucket foundation without wind turbine. In the frequency range of the first and second eigenfrequency (0.2 Hz < f < 5 Hz), the system behaves linearly. Here, the Frequency Domain Decomposition is used for identification and monitoring. For the lower frequency band (0.05 Hz < f < 0.2 Hz) where higher forces and displacements occur, a non-linear multilayer perceptron is chosen to model the non-linear relations between measurements. By applying two mathematical models for the relevant frequency ranges, all the information from the measurement data can be used for system identification and novelty detection under varying environmental conditions.

KW - Frequency Domain Decomposition

KW - Multilayer perceptron

KW - Novelty detection

KW - Soil stiffness

KW - Suction bucket jacket

UR - http://www.scopus.com/inward/record.url?scp=85081670269&partnerID=8YFLogxK

U2 - 10.1016/j.marstruc.2020.102745

DO - 10.1016/j.marstruc.2020.102745

M3 - Article

AN - SCOPUS:85081670269

VL - 72

JO - Marine structures

JF - Marine structures

SN - 0951-8339

M1 - 102745

ER -