Improvement of Aeroelastic Stability of Hingeless Helicopter Rotor Blade by Passive Piezoelectric Damping
Chul Yong Yun and Seung Jo Kim
International Journal of Aeronautical and Space Sicences, vol. 7, no. 1, pp.54-64, 2006
Abstract : To augment weakly damped lag mode stability of a hingeless helicopter rotor blade in hover, piezoelectric shunt with a resistor and an inductor circuits for passive damping has been studied. A shunted piezoceramics bonded to a flexure of rotor blade converts mechanical strain energy to electrical charge energy which is dissipated through the resistor in the R-L series shunt circuit. Because the fundamental lag mode frequency of a soft-in-plane hingeless helicopter rotor blade is generally about 0.7/rev, the design frequency of the blade system with flexure sets to be so. Experimentally, the measured lag mode frequency is 0.7227/rev under the short circuit condition. Therefore the suppression mode of this passive damping vibration absorber is adjusted to 0.7227/rev. As a result of damping enhancement using passive control, the passive damper which consists of a piezoelectric material and shunt circuits has a stabilizing effect on inherently weakly damped lag mode of the rotor blades, at the optimum tuning and resistor condition.
Keyword : Piezoceramics, Shunt circuit, Passive damping, In hover, Hingeless helicopter, Lead-lag |