Adaptive Snubber-Type Magnetorheological Fluid–Elastomeric Helicopter Lag Damper

摘要

A snubber-type magnetorheological uid–elastomeric lag damper is developed to provide adaptive lead-lagndamping augmentation for a hingeless helicopter rotor. The magnetorheological fluid–elastomeric lag dampernconsists of a flow valve, a flexible snubber body, and a flexible center wall separating the body into two fluidnchambers.Magnetorheological fluid enclosed in the snubber body can flow through two magnetorheological valvesnand be activated by amagnetic field in the valves. Consistent with the loading conditions for a helicopter lag damper,nthemagnetorheological fluid–elastomeric damper is tested under single and dual frequency excitations. The complexnmodulus method was used to compare the magnetorheological fluid–elastomeric device damping performance withnthe baseline passive Fluidlastic damper. Asignificant controllable damping range is observed as current is applied tonthemagnetorheological valve in the magnetorheological fluid–elastomeric damper. Furthermore, to account for thennonlinear hysteresis behavior of themagnetorheological fluid–elastomeric damper and estimate the damping force, antime-domain hydromechanicalmodel is formulated based on lumped parameters.Model parameters are establishednusing damper geometry,material properties, and experimental data. Themodel is then applied to simulate the forcenvs displacement response and force time history under both single and dual frequency excitations.