The effect of electrode stiffness on the piezoelectric and elastic constants of a piezoelectric bar

Electrodes that are stiff and thick compared with the underlying piezoelectric substrate material can substantially change the effective piezoelectric and elastic constants from those values that would be obtained in the absence of electrodes. A simple analytical model for the stress distribution inside a composite piezoelectric bar, consisting of two outer electrode layers and one inner piezoelectric layer, is used to calculate the effective g31, g32, g33, and gh piezoelectric constants, as well as the effective si j (i, j=1,2,3) elastic compliance coefficients. Numerical results for copper-clad, voided poly(vinylidene fluoride) (PVDF) sheets are presented.