Nonlinear and time-dependent electromechanical behavior of polyvinylidene fluoride

This paper describes the results from electromechanical tests conducted on polyvinylidene fluoride (PVDF) sheets showing its nonlinear and time-dependent electromechanical behavior. Mechanical and electromechanical tests were carried out for both uniaxially stretched and biaxially stretched PVDF sheets. The tests show nonlinearity in both the stress-strain response and the time-dependent response. Electromechanical dynamic tests were conducted at various superimposed pre-stress conditions. From the dynamical electromechanical tests, it is found that both biaxially stretched and uniaxially stretched PVDF sheets exhibit pre-stress dependence of their electromechanical coefficients. In addition, an attempt has been made to model the mechanical and the electromechanical behavior using a simple three-parameter viscoelastic solid model. The model captures the trends observed in the experiments and is recommended as a useful tool for designs using these materials.