Efficiency of twist deformation of composite plate actuated by MFC

More and more composite structures containing active materials are applied to adaptive structures. The integration of active materials in structures has brought new characteristics but made the design more complicated. In this paper, the deformation of the active composite plate actuated by the macro fiber material (MFC) is studied. The purpose is to obtain the relationship between the twist deformation of the actuated composite plate and the MFC fiber laying and the actuation mode. Based on the elastic mechanics theory, the relationship between the strain of active fiber actuated by voltage and induced internal force and deformation of the composite plate is established. The solution of the problem is conducted using Ritz's method and taking the displacement function as a linear combination of the two-dimension beam-modes. The solving equation of the displacement field actuated by MFC is derived, and the analytical result is verified by the experiment. In order to evaluate the actuation effect of MFC composite plate under different conditions and to consider the bending-torsion coupling characteristics of composite plate deformation, the concept and the calculation of actuation efficiency of an active composite plate are proposed, which is based on the definition of equivalent bending and twist angle of section. Then the evolution of the actuation efficiency with the laying angle of MFC and the mode of input voltage is analyzed. Corresponding to different constraint conditions, the laying of piezoelectric fiber-direction and the selection of actuation-mode are given based on the obtained analysis results.