Finite Element Formulation for Active Composite Laminates

Smart structures are characterized by a synergistic integration of active materials into a passive structure connected by a control system to enable an automatic adaptation to changing environmental conditions. Piezoelectric materials are widely used as distributed sensors and actuators in smart structures, where especially hybrid composites - a combination of fiber-reinforced and piezoelectric laminae - are very powerful smart material systems. First, a brief review of the developed shell type finite element for smart composite structures is presented. It is a degenerated shell element based on the Reissner-Mindlin kinematical assumptions for modeling thin and moderately thick structures made of multilayered material including piezoelectric active layers polarized in the thickness direction. The main focus of the paper is put on the test examples originally proposed by other authors. The finite element results were compared with the reference solutions obtained by Ritz type approximations. The considered test cases investigate the effects of shell shallowness, bending/twisting coupling and the influence of the piezoelectric layer thickness on the deformation of the laminated structure.