Effect of graphene nano-sheets on the elastic and piezoelectric coefficients of unidirectional PZT-7A/polyimide hybrid composites

This research investigates the effect of adding graphene nano-sheets (GNSs) on the elastic and piezoelectric responses of PZT-7A piezoelectric fiber/polyimide hybrid composites. The constructional feature of this hybrid composite is such that unidirectional PZT-7A fibers are embedded into the GNS-filled polyimide material. A nested micromechanical modeling strategy based on the Mori-Tanaka scheme is developed to predict the effective properties of PZT-7A/GNS/polyimide hybrid composites. Parametric studies are performed in order to examine the influences of volume fraction, agglomeration and rolling-up of GNSs, and PZT-7A volume fraction on the piezoelectric hybrid composite coefficients. The results indicate that the elastic and piezoelectric properties of PZT-7A/polyimide composites can be improved by the uniform dispersion of GNSs. However, it is observed that the formation of GNS agglomeration into the polyimide matrix has a serious negative effect on the equivalent properties of piezoelectric hybrid composites. The present predictions are also compared with other results reported in the literature. It is believed that the modeling approach and outcomes of this research may help to design these kinds of novel and highly promising piezoelectric hybrid composites.