Electrochemical viscoelastic modeling to predict quasi-static and dynamic response of IPMC actuators

A nonlinear dynamic viscoelastic model of an ionic polymer metal composite (IPMC) actuator is presented based on the viscoelastic constitutive equations and an energy-based variational approach to acquire dynamic and quasi-static response. For this purpose, the equation of motion of an IPMC actuator is obtained by considering the actuator as a cantilever viscoelastic beam and utlizing continuum mechanic relations, Euler-Bernoulli beam theory, Hamilton's principle, and electrochemical properties of ionomer. This new model can simulate time-dependent tip displacement of the IPMC actuators and predict the back-relaxation that occurs in the Nafion-based IPMC actuator under an imposed step voltage. The transfer function derived from the proposed model provides a good frequency response prediction in comparison to the experimental results.This model also can be utilized to obtain mechanical response and vibration analysis of the IPMC sensors.