A parametric study on flexible electro-active composites: Importance of geometry and matrix properties

Active fiber composites comprised of long circular fibers embedded in an epoxy polymer, where the fibers are made of the piezoelectric ceramic lead zirconate titanate. The active fiber composites use interdigitated electrodes, which produce electric field lines parallel to the fiber direction instead of through-the-thickness. It is noted, however, that the d₃₃ of the active fiber composite is almost a third that of the lead zirconate titanate, mainly because of the significant mismatch in dielectric properties between the epoxy matrix and the ceramic fibers. The objective of the current work is to investigate the effects of active fiber composite geometry and polymer properties on the overall performance of active fiber composite in terms of mechanical displacement and electric potential. An active fiber composite model that considers several fibers, epoxy matrix, and electrode fingers (interdigitated electrodes) as part of the representative volume element is developed and implemented using finite element method. The model examines the effect of the interdigitated electrode parameters such as the spacing between the electrode's fingers and their width. The other parameters examined are the fiber diameter and matrix properties. This parametric study will lead to an optimized geometry and matrix that can be used for the manufacturing of next-generation active fiber composites with higher performance than what is currently available.