OPTIMUM PLACEMENT OF PIEZOELECTRIC SENSOR ACTUATOR FOR VIBRATION CONTROL OF LAMINATED BEAMS/

The optimum placement of a collocated piezoelectric sensor/actuator is investigated numerically and verified experimentally for vibration co ntrol of laminated composite beams, The finite element method is used for the analysis of dynamic characteristics of the laminated composite beams with the piezoceramic sensor/actuator. The damping and the stif fness of the adhesive layer and the piezoceramics are taken into accou nt in the process of finite element modeling, Tailoring that varies th e stiffness and the damping properties of the composite material is us ed. The stacking sequence of the laminated composite beam is [theta(4) /0(2)/90(2)](s), where theta = 0, 15, 30, 45, 60, 75, and 90 deg, The sensor/actuator attached to a structure changes the mass, the damping, and the stiffness of the entire structure, Thus, interaction between sensor/actuator and structure is very important in the vibration contr ol of a flexible structure, Modal damping (2 zeta omega) is chosen as a more appropriate performance index, because it is directly related t o the settling time of the vibration, The structural damping index (SD I) is defined from the modal damping. Weights for each vibrational mod e are taken into account in the SDI calculation. The optimum location of the sensor/actuator is determined as the point where the SDI is max imum, Numerical simulation and experimental results show that the SDI depends on outer-layer fiber orientations of the host structure, the l ocation, and the size of the sensor/actuator.