Composites with piezoelectric thin fibers – first evidence of piezoelectric behavior

Abstract

 The integration of functional components into composite materials is still a challenge for materials science. The integrated components themselves acting as sensor and/or as actuator should not interfere with the excellent mechanical properties of fiber-reinforced composite materials. Using this approach the implementation of ”one-dimensional”geometries – like fibers with small diameters – is recommended. Thin fibers consisting of piezoelectric materials like PZT are among the promising candidates offering the sensor/actuator coupling. Sol-gel processing is useful for fabricating PZT fibers thin enough to behave flexibly. Therefore, they offer the opportunity to make composite materials adaptive while maintaining the structural conformity. Sol-gel derived high-quality PZT fibers with diameters smaller than 30 μm have been successfully integrated into planar fiber architectures. Within them the fibers are oriented uni-directionally. These architectures are embedded with interdigital electrodes. After embedding the fiber/electrode architectures within glass fiber-reinforced polymers the fibers can be poled and become piezoelectric. The resulting structures were suitable to be tested as adaptive components. It has been demonstrated that such structures can detect impacts and tensions. They can also be driven actively leading to a vibration of the structure.