A pin-moment model of flexoelectric actuators

Abstract

Owning to the unique property of generating pure bending deformation, flexoelectric curvature actuators hold promise for various future applications, especially in the micro and nano scales. This paper proposes three models to predict the deformation of one-dimensional isotropic beams under the excitation of flexoelectric curvature actuators, including the pin-moment model, the pin-force-moment model and Euler-Bernoulli model. The pin-moment model represents the simplest model by only considering the moments interaction between the actuators and the beam at both ends, while the pin-force-moment model incorporate both the force and moment interactions. Comparison between the results of these two models with the Euler-Bernoulli model results indicates that the pin-moment model overestimates the curvature of the beam under a small thickness ratio of the beam and actuator, whereas a good agreement is reached between the pin-force-moment model results with that obtained by the Euler-Bernoulli-model. The accuracy of the pin-force-moment model and the Euler-Bernoulli model was further verified by a finite-element analysis. Therefore the pin-force-moment model could provide a simple and accurate method to characterise the performance of flexoelectric curvature actuators, enlightening the implementation of them for numerous future applications.