Experimental Validation of Tailboom Vibration Control Using Fluidic Flexible Matrix Composite Tubes

Rotorcraft tailbooms experience driveline component wear and structural fatigue, while causing passenger discomfort due to vibration excitation from the rotors, separated flow behind the rotor hub, vehicle maneuvers, and wind gusts. Fluidic Flexible Matrix Composite (F²MC) tubes, a new class of passive fluidic vibration treatments, are tested on a representative tailboom structure. Two pairs of F²MC tubes are mounted to the top and bottom of the tailboom and interconnected via a fluidic circuit with a tunable orifice to form a tuned vibration absorber. Experimental frequency responses are obtained to demonstrate that the tuned vibration absorber reduces response amplitude at the first vertical bending mode by over 70%, and that a partially closed orifice leads to a damped absorber that adds nearly 8% damping to the first mode. A model of a tailboom with F²MC tubes is developed and validated with the experimental results. The effect of fluid pre-pressure and tailboom forcing amplitude are studied.