Experimental Study of Rotor Blade Tip Clearance Control Utilizing Smart Structure Technology

In this paper the experimental development of a simple and effective vibration control scheme for a flexible cantilever beam employing smart structure technology is presented. Our goal is to develop a physically realizable means to actively control turbine rotor blade tip vibration with piezoceramic sensors and actuators. To include the flexible characteristics of rotor blades in our analysis, a flexible cantilever beam is used to simulate the dynamic behavior of the turbine blades due to external disturbances, generated by a magnetic shaker. The shaker was installed near the free end of the flexible beam to maximize the external excitations. Piezoceramic sensor and actuator were used and evenly distributed as elements of the smart structure. The mathematical model of the smart structure including the piezoceramic sensors and actuators was determined by combining both analytical and experimental schemes. Based on the derived experimental dynamic model, a proportional gain feedback controller was implemented to compensate for the vibratory deflections of the underlying structure. The results of the work show that the proposed control methodology along with the smart structure can suppress more than 80% of the measured structural vibration, which is considered satisfactory.