Centrifugal Pendulum Dynamic Vibration Absorber for Helicopter Blades

Resumo

A large part of the engineering problems in rotating machines are related to vibration. This shortcoming
causes discomfort, wear and fatigue, leading to structural failures if they are not properly controlled. The main
techniques used to reduce the amplitudes of vibration include the installation of Dynamic Vibration Absorbers
(DVAs) which vary roughly from passive, semi-passive, semi-active and active, differing mainly in two aspects: i)
frequency range where it is effective and ii) external energy consumption. In rotating machines such as helicopter
blades, a type of DVA historically used is the Centrifugal Pendulum DVA (CPDVA), the use of this passive DVA
is justified due to the frequency of rotation of the helicopter rotor remains almost constant during its operation and
for the complexity of installing an active system on the blade. In this work, we will design a numerically passive
CPDVA. The blade and the absorber are modelled as beams using Finite Element Method (FEM) and validated
with analytical previous studies. Results show a good agreement with reality and theoretical expected behaviour,
the CPDVA attended the function it was designed.