A Delay Vector Variance based Marker for an Output-Only Assessment of Structural Changes in Tension Leg Platforms

Although aspects of power generation of many offshore renewable devices are well understood, their dynamic responses under high wind and wave conditions are still to be investigated to a great detail. Output only statistical markers are important for these offshore devices, since access to the device is limited and information about the exposure conditions and the true behaviour of the devices are generally partial, limited, and vague or even absent. The markers can summarise and characterise the behaviour of these devices from their dynamic response available as time series data. The behaviour may be linear or nonlinear and consequently a marker that can track the changes in structural situations can be quite important. These markers can then be helpful in assessing the current condition of the structure and can indicate possible intervention, monitoring or assessment. This paper considers a Delay Vector Variance based marker for changes in a tension leg platform tested in an ocean wave basin for structural changes brought about by single column dampers. The approach is based on dynamic outputs of the device alone and is based on the estimation of the nonlinearity of the output signal. The advantages of the selected marker and its response with changing structural properties are discussed. The marker is observed to be important for monitoring the as- deployed structural condition and is sensitive to changes in such conditions. Influence of exposure conditions of wave loading is also discussed in this study based only on experimental data.

[1]  Danilo P. Mandic,et al.  Signal nonlinearity in fMRI: a comparison between BOLD and MION , 2003, IEEE Transactions on Medical Imaging.

[2]  Danilo P Mandic,et al.  Indications of nonlinear structures in brain electrical activity. , 2003, Physical review. E, Statistical, nonlinear, and soft matter physics.

[3]  Sjur Neuenkirchen Godø.  Dynamic Response of Floating Wind Turbines , 2013 .

[4]  Srinivas Kuntamalla,et al.  The Effect of Aging on Nonlinearity and Stochastic Nature of Heart Rate Variability Signal Computed using Delay Vector Variance Method , 2011 .

[5]  X Munduate,et al.  Aerodynamic Thrust Modelling in Wave Tank Tests of Offshore Floating Wind Turbines Using a Ducted Fan , 2014 .

[6]  T. Schreiber,et al.  Surrogate time series , 1999, chao-dyn/9909037.

[7]  Jason Jonkman,et al.  Engineering Challenges for Floating Offshore Wind Turbines , 2007 .

[8]  D. Mandic,et al.  Dynamic response mitigation of floating wind turbine platforms using tuned liquid column dampers , 2015, Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences.

[9]  Hsien Hua Lee,et al.  Response mitigation on the offshore floating platform system with tuned liquid column damper , 2006 .

[10]  Yourong Li,et al.  Detecting the Nonlinearity in Time Series from Continuous Dynamic Systems Based on Delay Vector Variance Method , 2007 .

[11]  Jason Jonkman,et al.  Dynamics Modeling and Loads Analysis of an Offshore Floating Wind Turbine , 2007 .

[12]  Fuliang Yin,et al.  Diesel Engine Fault Information Acquisition Based on Delay Vector Variance Method , 2009, 2009 Second International Symposium on Knowledge Acquisition and Modeling.

[13]  S. Yalla,et al.  Optimum Absorber Parameters for Tuned Liquid Column Dampers , 2000 .

[14]  Danilo P. Mandic,et al.  Recurrent Neural Networks for Prediction: Learning Algorithms, Architectures and Stability , 2001 .

[15]  D.P Mandic,et al.  On the characterization of the deterministic/stochastic and linear/nonlinear nature of time series , 2008, Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences.

[16]  Danilo P. Mandic,et al.  Recurrent Neural Networks for Prediction: Learning Algorithms, Architectures and Stability , 2001 .

[17]  M. Hulle,et al.  The Delay Vector Variance Method for Detecting Determinism and Nonlinearity in Time Series , 2004 .

[18]  Biswajit Basu,et al.  Experimental Detection of Sudden Stiffness Change in a Structural System Employing Laser Doppler Vibrometry , 2012 .

[19]  J. Murphy,et al.  Dynamic response signatures of a scaled model platform for floating wind turbines in an ocean wave basin , 2015, Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences.

[20]  Vikram Pakrashi,et al.  Dynamic Responses of a Scaled Tension Leg Platform, Wind Turbine Support Structure in a Wave Tank , 2013 .

[21]  Rui Guo,et al.  Nonlinear Analysis in TCM Acoustic Diagnosis Using Delay Vector Variance , 2008, International Conferences on Biomedical and Bioinformatics Engineering.

[22]  Takeshi Ishihara,et al.  Dynamic response analysis of floating offshore wind turbine with different types of heave plates and mooring systems by using a fully nonlinear model , 2012 .