Coupled Durability and Functionality of Piezoelectric Polymers

Abstract

The main characteristic of piezoelectric polymers is coupling of their mechanical and physical properties. In this view, progressive material degradation of the polymers under cyclic loading conditions is an important factor in terms of both their long-term integrity and functional performance. The study reported herein demonstrates that the piezoelectric polymer polyvinylidene fluoride (PVDF) tends to exhibit accelerated creep rates under superimposed static and cyclic loads. Creep acceleration under such conditions has been observed even in the range of stresses well below the viscoelastic linearity limit. In the paper, the effects of material degradation caused by creep-fatigue interaction in PVDF are discussed. The study includes efforts to develop a constitutive viscoelastic material model taking into account damage evolution due to synergistic creep-fatigue interaction effects. The model is based on the principles of continuum damage mechanics and linear viscoelasticity.