Active Fibre Composites: Optimization of the manufacturing process and their poling behavior

摘要

The scientific community has put significant efforts into the manufacturing and optimization of sensors and actuators made of piezoelectric fibres with interdigitated electrodes, well known as Active Fibre Composites (AFC). A great advantage of such AFC is their flexibility and the possibility to integrate them into composite structures. In the current study an approach of optimizing the manufacturing process as well as the polarization of AFCs utilizing piezoelectric Lead-Zirconate-Titanate (PZT) fibres embedded in an epoxy matrix between interdigital Electrodes (IDE) screenprinted on Kapton will be discussed. During the poling process, an electric field is applied over the interdigitated electrodes of the AFC to its piezoelectric fibres along the fibre axis. One of the most important parameters of this polarization is - beside temperature and time - the applied voltage. An increase of the electric field results in an increase of the AFCs performance as shown by free-strain measurements. The manufacturing process developed and used at Empa consists of laminating the piezoelectric fibres in an epoxy matrix between the electrodes. An essential goal of this lamination - carried out in a hot press - is to get a proper contact between piezo fibres and the electrode. By adding soft layers between the Kapton foil and the mould, the interdigitated electrodes are deformed by each single fibre and therefore build up a contact area which in its cross section can be described by a contact angle. This optimization of the manufacturing process is also shown by free strain measurements of the AFC.