Comparison of QOS Fixed and Limited Interleaved Polling with Cyclic Demand Proportionality Algorithms

2009 ◽  
Author(s):  
Sadeta Krijestorac ◽  
Jonathan Bagby
Keyword(s):  
Cyclic Demand

scholarly journals Reconstructing Stress Resultants in Wind Turbine Towers Based on Strain Measurements

2021 ◽  
pp. 224-235
Author(s):  
Marko Kinne ◽  
Ronald Schneider ◽  
Sebastian Thöns
Keyword(s):  
Wind Turbine ◽  
Wind Waves ◽  
Support Structures ◽  
Strain Measurements ◽  
Cyclic Stresses ◽  
Waves And Currents ◽  
Wind Turbine Towers ◽  
The Individual ◽  
Cyclic Demand ◽  
Dynamic Phenomena

AbstractSupport structures of offshore wind turbines are subject to cyclic stresses generated by different time-variant random loadings such as wind, waves, and currents in combination with the excitation by the rotor. In the design phase, the cyclic demand on wind turbine support structure is calculated and forecasted with semi or fully probabilistic engineering models. In some cases, additional cyclic stresses may be induced by construction deviations, unbalanced rotor masses and structural dynamic phenomena such as, for example, the Sommerfeld effect. Both, the significant uncertainties in the design and a validation of absence of unforeseen adverse dynamic phenomena necessitate the employment of measurement systems on the support structures. The quality of the measurements of the cyclic demand on the support structures depends on (a) the precision of the measurement system consisting of sensors, amplifier and data normalization and (b) algorithms for analyzing and converting data to structural health information. This paper presents the probabilistic modelling and analysis of uncertainties in strain measurements performed for the purposes of reconstructing stress resultants in wind turbine towers. It is shown how the uncertainties in the strain measurements affect the uncertainty in the individual components of the reconstructed forces and moments. The analysis identifies the components of the vector of stress resultants that can be reconstructed with sufficient precision.

Cyclic-demand spectrum

2002 ◽  
Vol 31 (7) ◽  
pp. 1441-1457 ◽  
Author(s):  
Praveen K. Malhotra
Keyword(s):  
Cyclic Demand
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