Study on Equivalent Damping in Nonlinear Fluidlastic Damper of Helicopter Rotor

Abstract

A fluidlastic damper is a kind of novel lead-lag damper for a helicopter rotor, which possesses of stable dynamic properties but strong nonlinear performance. We have proposed dynamic equation of the rotor/fluidlastic damper coupling system to study the influence of fluidlastic damper dynamic characteristics on the helicopter rotor and calculated the response of the coupling system. The equivalent damping of the fluidlastic damper is identified from the response by decaying envelope-curves method, whose value is well consistent with that calculated by complex modulus method. Furthermore, the response of the coupling system with linear equivalent damping is found similar to that with nonlinear damping. Therefore, our linear model can basically reflect the dynamic properties of fluidlastic damper, promising the application of the equivalent damping of fluidlastic damper in predigesting aerodynamic stability calculation of the rotor/fluidlastic damper coupling system.