THE INFLUENCE OF GEOMETRIC STIFFNESS IN THE SIMULATION OF A WIND TURBINE TOWER

Resumo

Taking into account that technological advances have enabled increasingly slender projects, it is increasingly
necessary to study the influence of second order effects on the behavior of structural elements. When a flexural element
is subjected to a significant axial load its elastic stiffness is altered. Wind towers are an example of this, in addition to
being subject to bending by the incidence of wind action, they support a large compression load. Item 15.1 of NBR
6118:2014 states that the assessment of the second-order effects occurs when the balance analysis is conducted
considering the configuration of the deformed. Thus, the present work aims to study the dynamic response of a wind
tower considering the influence of geometric nonlinearity resulting from the weight that the tower supports. The
modeling of the structure performed in ANSYS adopts the geometric simplification of the blades of Murtagh et al [1].
To experiment with the computational procedure used in the analysis of the tower, a beam cantilever submitted to a
normal static compression load and a transverse dynamic load at the free end was evaluated. The results obtained by
the analytical procedure and numerical simulation were compared and, besides to presenting a good agreement with
what is expected, shows the influence of pre-tensioning on the bending resistance of a piece.