Analysis of structural damping effects on the dynamic response of a wind turbine blade

• Κύριος συγγραφέας: Παπανακλής, Γεώργιος
• Άλλοι συγγραφείς: Papanaklis, George
• Γλώσσα: English
• Έκδοση: 2022
• Θέματα: Wind turbine blades; Finite element methods; Structural damping effect; Dynamic simulation; Strength analysis; Πτέρυγες ανεμογεννήτριας; Μέθοδος πεπερασμένων στοιχείων; Προσομοίωση δυναμικής απόκρισης; Δομική ανάλυση

The main aim of the present Diploma thesis is the development of a Reference Wind Turbine blade’s numerical model and the implementation of structural dynamic analyses in order to evaluate the structural damping effects and the structural integrity of the blade. During the last decades, the need for renewable energy that has lower environmental impact has increased exponentially, drawing the attention of the scientific and industrial community towards the wind energy sector and leading them to put some serious effort on the development of larger and more efficient wind turbines as also dedicated analysis and design tools. In this work, some theoretical background related to the wind turbine blades’ structure and aerodynamic loads is provided, along with a brief presentation of the modelling methods that are used for the simulation of the blade’s dynamic response. Dedicated wind turbine simulation tools are examined regarding their framework, as well as the aerodynamic and structural theories and approaches they employ for the simulation of the entire mechanism. The theoretical part of this thesis is completed with the review of composites’ loss factors and proportional damping, while the definition of Rayleigh factors that will be utilized in the numerical models is explained. Before the description of the blade’s model, a brief review of the two numerical tools (hGAST and DAMPBEAM) that provide data for the modeling and structural assessment of the component takes place. During the definition of the wind turbine’s blade model in Abaqus, the CAD model is created, material properties and composite layups are defined, available dynamic analysis methods and procedures are examined, load modeling is described, and the meshing strategy is explained. The implementation of modal analysis provides the eigenfrequencies and eigenmodes of the structure that are successfully compared with the respective ones from the DAMPBEAM code. For the damping assessment, various dynamic analyses are performed, where different aerodynamic load cases, damping properties and analysis methods are employed and their results are compared, extracting important conclusions for the effect of each parameter. Finally, blade’s structural integrity is evaluated using Tsai-Wu stress-based and maximum strain failure criteria, validating that structure’s capability of dealing with the load condition of the simulated operation when damping is taken into consideration.