Feasibility of modal expansion for virtual sensing in offshore wind jacket substructures

2021 ◽  
Vol 79 ◽  
pp. 103019
Author(s):  
Dawid Augustyn ◽  
Ronnie R. Pedersen ◽  
Ulf T. Tygesen ◽  
Martin D. Ulriksen ◽  
John D. Sørensen
Keyword(s):  
Offshore Wind ◽  
Modal Expansion ◽  
Virtual Sensing

scholarly journals Optimal Sensor Placement for Reliable Virtual Sensing Using Modal Expansion and Information Theory

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3400
Author(s):  
Tulay Ercan ◽  
Costas Papadimitriou
Keyword(s):  
Utility Function ◽  
Measurement Errors ◽  
Structural Model ◽  
Information Gain ◽  
Sensor Placement ◽  
Optimal Sensor Placement ◽  
Modal Expansion ◽  
Expected Information ◽  
Virtual Sensing ◽  
Multidimensional Integral

A framework for optimal sensor placement (OSP) for virtual sensing using the modal expansion technique and taking into account uncertainties is presented based on information and utility theory. The framework is developed to handle virtual sensing under output-only vibration measurements. The OSP maximizes a utility function that quantifies the expected information gained from the data for reducing the uncertainty of quantities of interest (QoI) predicted at the virtual sensing locations. The utility function is extended to make the OSP design robust to uncertainties in structural model and modeling error parameters, resulting in a multidimensional integral of the expected information gain over all possible values of the uncertain parameters and weighted by their assigned probability distributions. Approximate methods are used to compute the multidimensional integral and solve the optimization problem that arises. The Gaussian nature of the response QoI is exploited to derive useful and informative analytical expressions for the utility function. A thorough study of the effect of model, prediction and measurement errors and their uncertainties, as well as the prior uncertainties in the modal coordinates on the selection of the optimal sensor configuration is presented, highlighting the importance of accounting for robustness to errors and other uncertainties.

Effective virtual sensing scheme for fatigue assessment of monopile offshore wind turbines

2016 ◽  
pp. 305-310 ◽  
Author(s):  
A. Iliopoulos ◽  
D. Van Hemelrijck ◽  
N. Noppe ◽  
W. Weijtjens ◽  
C. Devriendt
Keyword(s):  
Wind Turbines ◽  
Offshore Wind ◽  
Fatigue Assessment ◽  
Offshore Wind Turbines ◽  
Virtual Sensing

scholarly journals VIRTUAL SENSING AND STRAIN ESTIMATION ON AN OFFSHORE WIND TURBINE USING SUPERVISED LEARNING

2021 ◽  
Author(s):  
Marius Tarpø ◽  
Sandro Amador ◽  
Evangelos Katsanos ◽  
Mattias Skog ◽  
Johan Gjødvad ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Supervised Learning ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Strain Estimation ◽  
Virtual Sensing

Strain estimation for offshore wind turbines with jacket substructures using dual-band modal expansion

2020 ◽  
Vol 71 ◽  
pp. 102731 ◽  
Author(s):  
M. Henkel ◽  
J. Häfele ◽  
W. Weijtjens ◽  
C. Devriendt ◽  
C.G. Gebhardt ◽  
...  
Keyword(s):  
Wind Turbines ◽  
Offshore Wind ◽  
Dual Band ◽  
Modal Expansion ◽  
Offshore Wind Turbines ◽  
Strain Estimation

scholarly journals Fatigue Stress Estimation for Submerged and Sub-Soil Welds of Offshore Wind Turbines on Monopiles Using Modal Expansion

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7576
Author(s):  
Maximilian Henkel ◽  
Wout Weijtjens ◽  
Christof Devriendt
Keyword(s):  
Wind Turbines ◽  
Wind Farm ◽  
Measurement Data ◽  
Offshore Wind ◽  
Strain History ◽  
Fe Model ◽  
Modal Expansion ◽  
Operational Conditions ◽  
Offshore Wind Turbines ◽  
Farm Operators

The design of monopile foundations for offshore wind turbines is most often driven by fatigue. With the foundation price contributing to the total price of a turbine structure by more than 30%, wind farm operators seek to gain knowledge about the amount of consumed fatigue. Monitoring concepts are developed to uncover structural reserves coming from conservative designs in order to prolong the lifetime of a turbine. Amongst promising concepts is a wide array of methods using in-situ measurement data and extrapolating these results to desired locations below water surface and even seabed using models. The modal decomposition algorithm is used for this purpose. The algorithm obtains modal amplitudes from acceleration and strain measurements. In the subsequent expansion step these amplitudes are expanded to virtual measurements at arbitrary locations. The algorithm uses a reduced order model that can be obtained from either a FE model or measurements. In this work, operational modal analysis is applied to obtain the required stress and deflection shapes for optimal validation of the method. Furthermore, the measurements that are used as input for the algorithms are constrained to measurements from the dry part of the substructure. However, with subsoil measurement data available from a dedicated campaign, even validation for locations below mud-line is possible. After reconstructing strain history in arbitrary locations on the substructure, fatigue assessment over various environmental and operational conditions is carried out. The technique is found capable of estimating fatigue with high precision for locations above and below seabed.

Fatigue assessment of offshore wind turbines on monopile foundations using multi-band modal expansion

Wind Energy ◽  
2017 ◽  
Vol 20 (8) ◽  
pp. 1463-1479 ◽  
Author(s):  
Alexandros Iliopoulos ◽  
Wout Weijtjens ◽  
Danny Van Hemelrijck ◽  
Christof Devriendt
Keyword(s):  
Wind Turbines ◽  
Offshore Wind ◽  
Fatigue Assessment ◽  
Modal Expansion ◽  
Offshore Wind Turbines ◽  
Multi Band
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