Double Inclusion Model for Multifunctional Piezoelectric Composites

Abstract

Listen

Translate article

A new approach to predict the electroelastic properties of multiphase piezoelectric composites is proposed and its validity is demonstrated on a new form of piezoelectric fiber composite (PFC). PFCs are a group of materials recently developed in order to overcome the fragile nature of monolithic piezoceramic materials. Several PFC designs have been developed; however, because the electrodes are generally separate from the piezoelectric fiber they can be difficult to embed into the composite. This limitation has typically left these materials as surface-bonded sensor or actuators that are generally separate from the structure. If the fibers are embedded they provide little strength to the composite due to their low tensile modulus compared with traditional reinforcements. To avoid the limitations associated with current PFCs, a novel active structural fiber (ASF) was developed that can be embedded in a composite material to perform sensing and actuation, in addition to providing load bearing functionality [1]. Currently only a one dimensional model has been developed to predict the effective longitudinal piezoelectric coupling coefficient of the ASF and a lamina incorporating the fiber. In order to fully understand the electroelastic properties of the material, this paper will introduce a three dimensional micromechanics model to estimate the effective electroelastic properties of the multifunctional composites with different design parameters. The three dimensional model is formulated by extending the double inclusion model to multiphase composites with piezoelectric constituents. The double inclusion model is modified by applying the principles used to adapt the Mori-Tanaka model for two phase piezoelectric composites, which has been shown to be very accurate for two phase materials. The double inclusion model has been chosen for the ASF studied here because it is designed to model composites reinforced by inclusions with multi-layer coatings. The accuracy of our extended double inclusion model will be evaluated through a three dimensional finite element analysis (FEA) on a representative volume element (RVE) of the ASF composite. The results will demonstrate that the micromechanics model developed here can very accurately predict the electroelastic properties of the multifunctional composites.