Forced Vibration of Composite Sandwich Beams with Piezoelectric Sensors and Actuators

Although some investigations such as buckling and free vibration of c omposite sandwich beams have been done analytically, it's rarely seen the analytical work about the forced vibration of composite sandwich beams. In our study, we get the closed form solution for the free vibration problems and derive an orthogonality relation consisting the effects of rotary inertia and shear deformation. Unlike the usual orthogonality relation for shallow beams in which the modal shapes are the shapes of deflections corresponding to the natural frequencies, the relation for the present problem can not stand without including the rotation angles. Through the establishment of the orthogonality relation, the forced vibration problems can then be solved by modal analysis. The analytical solution of the forced vibration is useful for the study of vibration control. In this study we investigate smart composite sandwich beams with surface bonded piezoelectric sensors and actuators. The piezoelectric sensors can respond to structural vibration and generate output voltage due to the direct piezoelectric effect. On the other hand, the actuators can induce force and moment and control the system due to the converse piezoelectric effect.