Banca de DEFESA: Rafael Neponuceno Batista

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : Rafael Neponuceno Batista
DATE: 19/12/2023
TIME: 09:00
LOCAL: Apresentação remota via Microsoft Teams
TITLE:

Analytical-numerical dynamic analysis of wind turbine towers equipped with tuned liquid column dampers.

KEY WORDS:

Structural dynamics. Wind turbines. Tuned Liquid Column Dampers. Vibration control.

PAGES: 145
BIG AREA: Engenharias
AREA: Engenharia Civil
SUBÁREA: Estruturas
SPECIALTY: Mecânica das Estruturas
SUMMARY:

Wind energy generation has established itself as a sustainable alternative in the energy matrix whose installed power has consistently grown over the years. The development of new wind turbine designs with large nominal capacities and dimensions makes it essential to study the vibrations of their structures and devices that can reduce their displacements. This work uses analytical and numerical approaches for dynamic analysis of horizontal axis wind turbine structures, also evaluating the effects of using tuned liquid column dampers (TLCDs) as passive devices to reduce structural displacements. Computational routines were developed to simulate wind turbines by discretizing the towers into beam finite elements with subsequent application of the static condensation process to eliminate the system's rotational degrees of freedom. The implementations were introduced in a new version of the software DynaPy, allowing the analysis of these structures equipped with TLCD and subjected to harmonic excitations and seismic loading. Furthermore, an analytical approach was used to represent the structure as a single degree of freedom system with generalized properties, from which parametric TLCD analyses were conducted to assist in the optimal sizing of the device. The natural frequencies and mode shapes obtained through the model with static condensation showed good agreement with the referential values when the rotational inertia of the mass at the extremity is ignored. When considering this parameter, accuracy became restricted to the first mode. Despite this, the model was well suited to determining the structure's response in the time domain, which was also observed for the simplification method with generalized properties. Analyses of the structure equipped with TLCD on DynaPy demonstrated the device's efficiency in reducing vibrations. It was also possible to visualize the influence of the number of TLCDs and the opening ratio of the diaphragm on the behavior of the structure and liquid column of the attenuator. Finally, the parametric analysis confirmed the importance of choosing a tuning ratio close to the unity value when sizing the TLCD. It also indicated an increase in the device's efficiency as the mass and aspect ratios were set to higher values.

COMMITTEE MEMBERS:
Presidente - 404485 - LINEU JOSE PEDROSO
Interno - 6669206 - LUCIANO MENDES BEZERRA
Externa à Instituição - ELIANE MARIA LOPES CARVALHO - UFF