Model development for piezoelectric polymer unimorphs

This paper addresses the development of distributed models for unimorphs comprised of an active PVDF layer bonded to an inactive polyimide layer. Thin beam theory is employed to quantify displacements along the unimorph length as a function of input voltages. The theory is based on the assumption of linear piezoelectric relations but is posed in a format which can be directly extended to incorporate dielectric hysteresis and nonlinearities if the application warrants. A variety of structural damping models are considered and it is illustrated that in low drive regimes, the assumption of Kelvin-Voigt damping produces a unimorph model which accurately predicts the elliptic losses measured in experimental data.