ABSTRACT
To resolve the inadequacies of monolithic piezoceramic materials, researchers have developed composite piezoelectric materials consisting of an active piezoceramic fiber embedded in a polymer matrix. Configuration of material in this way is advantageous because typical crystalline materials have much higher strengths in the fiber form due to reduced volume fractions of flaws during fabrication (Williams et al. 2002). Also, in addition to providing improved robustness by protecting the fragile fibers, the flexible nature of the polymer matrix allows the material to be able to more easily conform to the curved surfaces found in more realistic industrial applications. These advantages have been capitalized on by the development of a new group of devices called piezoelectric fiber composites (PFCs). Research in this area led to the development of a broad range of active PFC actuators, including active fiber composites (AFCs) (Bent and Hagood 1993a,b, Bent et al. 1995), macrofiber composites (MFCs) (Wilkie et al. 2000), 1-3 composites, and the hollow fiber composite (Cannon and Brei 2000). These PFCs are designed to fulfill the specific purpose of structural sensing and actuation and are typically constructed in the form of a patch of material that can be bonded to the surface of a structure or laid up as “active layers” along with conventional fiber-reinforced lamina. While the PFC provides significant advantages over monolithic piezoceramics, they are separated from the structural components and are not intended to provide any load-bearing functionality.
