Development of a smart moving blade tip activated by a piezo-induced bending-torsion coupled beam

This paper presents an active moving blade tip for a smart rotor with torsional actuation via a piezo-induced bending-torsion coupled composite beam. A novel spanwise variation in the beam layup and piezoceramic element phasing is used to maximize the twist response, while minimizing the bending response. The composite beam is located lengthwise within the blade with surface bonded piezoceramic elements excited to induce spanwise and chordwise bending of the beam. The bending results in an induced twist via the structural coupling and this twist deflects the moving tip. A proof-of-concept actuator beam was developed and tested. Tip twist with essentially zero tip bending deformation was demonstrated. Two operational 1/8th scale model rotor blades were manufactured for hover testing. In non-rotating calibration tests, at a 60 Hz actuator excitation, a peak to peak moving tip deflection of 4 deg was achieved.