PowerPoint Presentation
Dynamic soil-structure interaction issues of offshore wind
turbinesAuthors:Lszl Arany, University of BristolProf Subhamoy
Bhattacharya, University of SurreyProf S. John Hogan, University of
BristolDr John Macdonald, University of Bristol
Background and motivationFuture offshore wind farms: larger, in
deeper waters, farther offshoreHow to choose the best
foundation?Conceptual/preliminary design - Dynamics
Task carried outMechanical / mathematical model
Frequency equation solved numericallyFitted analytical
expressions
Task carried outAnalytical expressions for quick natural
frequency estimation and sensitivity analysis were formulated for
offshore wind turbines on flexible foundations.Structure of the
presentationImportance of dynamics and structural model with
soil-structure interactionNatural frequency equation and
resultsFitted analytical expressionsOffshore wind turbines are
dynamically sensitive structuresDynamic loading
fromwindwavesturbine rotation (1P)blade passage (3P).
Frequency content of dynamic loads for a typical wind
turbine)Dynamic model of the wind turbine
Foundation modelling with 3 springs
Source: EWEA (2012)Structure of the presentationImportance of
dynamics and structural model with soil-structure
interactionNatural frequency equation and resultsFitted analytical
expressionsModel parameters
of the tower
Equation of motionTranscendental equation: solved
numerically
Offshore Wind Turbine Frequencies (OWTF v1.0) software was
developed.Natural frequency vs. model parameters
Fixed base frequencyEstimated valuesStructure of the
presentationStructural model and dynamics including soil-structure
interactionNatural frequency equation and results Fitted analytical
expressionsApproximation of the natural frequency
Fitted analytical curves
SummaryA mathematical model was developed.Software was written
to solve the frequency equation numerically.Sensitivity of natural
frequency can be analysed.Analytical formulae were fitted to the
curves.Thank you!Natural frequency vs. model parametersNatural
frequency vs. model parameters
Equation of motionBoundary conditions
Solution: transcendental equationBoundary conditionsEquation of
motion
