Active damping of piezolaminated composite beams using combined extension and shear piezoelectric mechanisms

The present study describes a comprehensive investigation performed to study the effects of piezoceramic materials on the active damping of vibrating piezo-composite beams. The active damping is obtained by using an actuator and a sensor made of piezoceramic layers, acting in 'closed-loop'. By transferring the accumulated voltage on the sensor layer to the piezoelectric actuator layer, causes the beam to actively damp-out its vibrations. The voltage transferred from the sensor to the actuator has to be amplified through a feedback gain. An exact mathematical model based on a first order shear deformation theory (FSDT) was developed and described in order to study the effect of all four piezoelectric 'closed-loop' combinations (EE, SS, ES and SE). The first two combinations use only one piezoelectric mechanism, extension or shear, as both sensors and actuators, while the other two use piezoelectric mechanisms, extension and shear, in a combined 'closed-loop'. Using the present model, both natural and damped vibrations were calculated. Parametric studies were performed for investigating the required feedback gain, G, of each piezoelectric combination, and the effect of piezoelectric materials on damping higher frequencies was also studied.