smart machines with flexible rotors

the concept of smart machinery is of current interest. several technologies are relevant in this quest including magnetic bearings, shape memory alloys (sma) and piezo-electric activation. recently, a smart bearing pedestal was proposed based on smas and elastomeric o-rings. however, such a device is clearly relevant only for the control of rigid rotors, for flexible rotors there is a need for some modification on the rotor itself. in this paper, rotor actuation by piezo-electric patches on the rotor is studied. a methodology is presented for the calculation of rotor behaviour and appropriate control strategies are discussed.