Integration of piezoceramic composites into structural components: Effect on the polarisation state and polarisability

In lightweight construction, structural components with integrated piezoelectric sensors and actuators find application for condition monitoring, structural health monitoring, vibrational control, and reduction of noise emission. In order to create such multifunctional, so-called smart components, an integration technique for serial production, designed for embedding of piezofibre composites into thermoplastic structures, was developed recently. During the two-stage fabrication process, thermal and mechanical loads act on the piezoceramic, which can lead to partial depolarisation and thus degradation of the piezoelectric properties. Since the mechanical boundary conditions are significantly differing between the manufacturing stages, a direct determination and subsequent comparison of the piezoelectric values appears very difficult. Therefore, the effect of each process step of integration (here called integration step) on the polarisation state and polarisability of the piezofibre composites was investigated directly. The results indicate distinctive effects depending on the particular integration step. For the investigated integration technique, the overall depolarisation remains in a range which seems acceptable for low power applications such as sensing. However, for actuation the results suggest re-poling or poling after integration to assure maximum piezoelectric performance.