Effect of flexoelectricity on the electromechanical response of graphene nanocomposite beam

Owing to its unique multifunctional and scale-dependent physical properties, graphene is emerged as promising reinforcement to enhance the overall response of nanotailored composite materials. Most recently, the piezoelectricity phenomena in graphene sheets was found through interplay between different non-centrosymmetric pores, curvature and flexoelectricity phenomena. This has added new multifunctionality to existing graphene and it seems the use of piezoelectric graphene in composites has yet to be fully explored. In this article, the mechanics of materials and finite element models were developed to predict the effective piezoelectric and elastic (piezoelastic) properties of the graphene reinforced nanocomposite material (GRNC). An analytical model based on the linear piezoelectricity and Euler beam theories was also developed to investigate the electromechanical response of GRNC cantilever beam under both electrical and mechanical loads accounting the flexoelectric effect. Furthermore, molecular dynamics simulations were carried out to determine the elastic properties of graphene which were used to develop the analytical and numerical models herein. The current results reveal that the flexoelectric effect on the elastic behavior of bending of nanocomposite beams is significant. The electromechanical behavior of GRNC cantilever beam can be tailored to achieve the desired response via a number of ways such as by varying the volume fraction of graphene layer and the application of electrical load. Our fundamental study highlights the possibility of developing lightweight and high performance piezoelectric graphene based nanoelectromechanical systems such as sensors, actuators, switches and smart electronics as compared with the existing heavy, brittle and toxic piezoelectric materials.