INVESTIGATING THE EFFECT OF THE ORTHOTROPIC PROPERTY OF PIEZOELECTRIC PVDF

Abstract

The applications of the piezoelectric Polyvinylidene Fluoride, PVDF, integrated with the beams, plates, and membranes, performing as sensor, actuator or combination have been received considerable attention in the recent years. However, not much work has been reported on the influence of the PVDF’s orthotropic behavior, particularly the effect of the orientation of the PVDF film in the host structure, on the performance of the system. In the present study, the effect of the piezoelectric PVDF film orientation on the output voltage, the actuation force, and the dynamic response of the integrated structures has been studied using the finite element method. In the sensory mode, the difference between the output voltages obtained from the biaxial piezoelectric PVDF film and uniaxial one, when the orientation of the film varies from 0 to 90 degree, is investigated. In each case the proportion contributions of the involved piezoelectric coefficients including d31, d32 and are studied. Alternatively, in the actuation mode, the effect of orthotropic behavior of the actuator on the nodal displacements has been taken into consideration. The influence of the material orthotropic property of the transducer on the free undamped response of the system is also investigated. Moreover an effective Young’s modulus and effective Poisson ratio for the uniaxial PVDF film has been introduced using an optimization procedure to minimize the error caused by isotropic assumption of uniaxial PVDF film.