Equivalent modeling for ionic polymer–metal composite actuators based on beam theories

Equivalent beam and equivalent bimorph beam models for IPMC (ionic polymer–metal composite) actuators are described in the ensuing paper. Important physical properties of IPMCs including Young's modulus and electro-mechanical coupling coefficient were determined using the rule of mixture, bimorph beam equations, and measured force–displacement data of a cantilevered IPMC actuator. By using a beam equation with estimated physical properties, the actuation displacements of a cantilevered IPMC actuator were calculated to show an excellent agreement between the computed tip displacements and the measured data. Finite element analysis (FEA), along with the predetermined physical properties, was used to predict the force–displacement relationship of an IPMC actuator, which is key data to effectively design many engineering devices of interest. Indicated by the results from the FEA agreeing with the measured data, the proposed models can be adopted for modeling of IPMC actuators with advanced shapes and other boundary conditions.