document: Induced-shear piezoelectric actuators for rotor blade trailing edge flaps Much of the current rotorcraft research is focused on improving performance by reducing unwanted helicopter noise and vibration . One of the most promising active rotorcraft vibration control systems is an active trailing edge flap . In this paper , an induced-shear piezoelectric tube actuator is used in conjunction with a simple lever-cusp hinge amplification device to generate a useful combination of trailing edge flap deflections and hinge moments . A finite-element model of the actuator tube and trailing edge flap -LRB- including aerodynamic and inertial loading -RRB- was used to guide the design of the actuator-flap system . A full-scale induced shear tube actuator flap system was fabricated and bench top testing was conducted to validate the analysis . Hinge moments corresponding to various rotor speeds were applied to the actuator using mechanical springs . The testing demonstrated that for an applied electric field of 3 kV cm/sup -1 / the tube actuator deflected a representative full-scale 12 inch flap + or-2 .8 degrees at 0 rpm and + or-1 .4 degrees for a hinge moment simulating a 400 rpm condition . The per cent error between the predicted and experimental full-scale flap deflections ranged from 4 % -LRB- low rpm -RRB- to 12.5 % -LRB- large rpm -RRB- . Increasing the electric field to 4 kV cm/sup -1 / results in + or-2 .5 degrees flap deflection at a rotation speed of 400 rpm , according to the design analysis . A trade study was conducted to compare the performance of the piezoelectric tube actuator to the state of the art in trailing edge flap actuators and indicated that the induced-shear tube actuator shows promise as a trailing edge flap actuator
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extractive_keyphrases: rotorcraft helicopter noise vibration control active trailing edge flap 12 inch flap inertial loading design shear tube actuator flap bench top testing piezoelectric tube actuator
abstractive_keyphrases: helicopter vibration lever-cusp hinge amplification device finite-element model aerodynamic loading induced-shear tube actuator 12 inch