Electro-active polymers are emerging new class of materials which conducting polymers, ionic polymer metal composites, gel polymers, etc are among them. The mechanism for volumetric change of conjugated polymer actuators is reduction/oxidation. In order to provide enhanced degree of understanding, it is necessary to have a comprehensive electro-chemomechanical modeling to predict the behavior of astonishing conducting polymer actuators. With this in mind, the object of this paper is to moot an appropriate nonlinear dynamic model for the fast trilayer bending actuators by taking advantage of the previously proposed distributed RC circuit for modeling electrical admittance for polypyrrole (PPy) polymers. The nonlinearity of this model is due to the von Kármán strains. Based on the Hamilton principle for the Timoshenko beam theory, the governing equations of motion are developed. The generalized differential quadrature method (GDQ) along with the Nemark formulation with the assistance of iterative Newton-Raphson method, to solve system of nonlinear equations, is utilized to treat the equations. Recently published experimental data is used to validate the results. The results show that considering geometric nonlinearity in modeling the dynamic behavior of these actuators has a noticeable effect on the beam deflection. For a cantilever beam with a tip attached concentrated mass, dynamic response is investigated.

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