Dynamic analysis of a composite material telecommunications tower under wind loads
Palavras-chave:
Pultruded composite, Telecommunications towers, Structural dynamics, Dynamic wind action, Vibration attenuatorsResumo
This work aims to analyze a glass fiber reinforced polymer (GFRP) telecommunications tower under
wind dynamic loads. The natural frequencies of the structure’s first lateral bending modes in both planes, obtained
from a numerical model using the Finite Element Method, were less than 1 Hz. According to the Brazilian standard
NBR 6123, with those values, a dynamic analysis of the structure under wind fluctuation is necessary. A Python
language program was developed in order to simulate the fluctuation of the wind and solve the dynamic
equilibrium equations. With the time domain analysis of the tower, large displacements at the top of the tower
were identified. To solve this problem, a nonlinear pendulum control system adjusted to the natural frequency of
the structure for both planes was designed. The coupled equations of motion of the structure and the controller
attached to its top were also implemented in the Python program, obtaining the controlled and uncontrolled
structure responses. For a set of random simulations of wind conditions, the efficiency of the nonlinear pendulum
control system in reducing displacements amplitudes in the two planes of the structure was assessed.
