A micromechanical formulation for piezoelectric fiber composites with nonlinear and viscoelastic constituents

This study presents a simplified micromechanical model to predict electromechanical behaviors of piezocomposites, having ferroelectric fibers and polymer matrix. A nonlinear electromechanical constitutive model is formulated for the ferroelectric fibers, i.e. PZT fibers. The nonlinearity is due to polarization switching in the PZT materials under high electric field and compression stress. Phenomenological models are used to represent stress–strain and polarization–electric field hysteresis responses during polarization switching. The nonlinear electromechanical constitutive relation is verified using hysteresis polarization and strain responses of PZT-51. Effective responses of piezocomposites at various fiber volume contents, generated using the simplified micromechanical model, are also compared with available experimental data. The effects of viscoelastic polymer matrix on the overall electromechanical hysteresis and creep behaviors of piezocomposites are also examined.