Active stiffening of laminated composite beams using piezoelectric actuators

The present study deals with the stiffening effects of a smart piezolaminated composite beam. The structure consists of piezoceramic layers or patches bonded on the surface of the beam. The analysis considers the linear piezoelectric constitutive relations and the first-order shear deformation theory (FSDT). The influence of the actuators is evaluated by means of the pin-force model and their size and location along the beam are taken into account. The three coupled equations of motion of a general non-symmetric piezolaminated composite beam subjected to axial and lateral tractions and various boundary conditions are numerically solved to obtain the natural frequencies and mode shapes. The results of the present model are compared with those based on a finite element analysis using the ANSYS code, as well as to results presented in the literature. All comparisons yielded very good matches. It is demonstrated that the stiffness of the beam can be actively altered using the piezoelectric bonded actuators, yielding significant changes in the natural frequencies and mode shapes of the beam. (C) 2002 Published by Elsevier Science Ltd.