Analytical modeling of the variation in apparent d/sub 33/ piezoelectric coefficient measured by the direct quasistatic method as a function of sample aspect ratio

In this study we present an analytical model in which apparent (measured) d/sub 33/ is a function of the aspect ratio, the mechanical properties of the contacts and the properties of piezoelectric ceramics. Using derived relations it is possible to obtain the true value of d/sub 33/ in the wide range of boundary conditions. The analytical results are compared with simulations using finite element modeling (FEM) and with experimental data, and good correlation is found among them. Effect of the geometry of the contacts used to apply the force and collect the piezoelectric charge from the sample on apparent d/sub 33/ value is specifically addressed.