An actuation method by a biconcave beam structure with converse flexoelectric effect

Converse flexoelectricity describes the linear relationship between an electric field gradient and the mechanical stress in dielectric materials. It is not restricted by the Curie temperature limit, does not require advanced electrical poling and a wide range of candidate materials exist; hence, there is growing interest in converse flexoelectricity for application in actuators. In this work, a biconcave beam structure and actuation method based on the converse flexoelectric effect is presented. Theoretical and finite element analyzes were developed for the relationship between the electric field gradient and the geometric parameters. A non-piezoelectric dielectric material, polyvinylidene fluoride, was experimentally applied to validate the designed effect. The experimental results show that the designed structure outputs markedly larger displacements magnitudes than the control specimens. This work provides a design method for converse flexoelectric actuators and further enhances the application prospects of converse flexoelectricity in all solid dielectric materials. (paper)