Conclusions

Abstract

This book has demonstrated to the reader that the analysis of the effective electromechanical properties must take into account a number of factors (components, connectivity, microgeometry, etc.) and the variety of averaging procedures that are available. These procedures become complicated due to electromechanical coupling in the presence of piezo-active components. The role of the ferroelectric components has been considered in detail, demonstrating that their remarkable piezoelectric properties are fundamental in forming the piezoelectric response of the composites with various connectivity patterns and / or different combinations of the components. Our study enables us to conclude that both the ferroelectric ceramic and single-crystal components within piezoelectric composites lead to considerable piezoelectric activity, sensitivity, anisotropy, and hydrostatic piezoelectric response in specific volume-fraction ranges. These properties have been determined for specific composite architectures, connectivity and components. In a number of cases, conventional ferroelectric ceramic / polymer composites with 1–3, 2–2 or 0–3 connectivity have electromechanical properties that can be further improved by using the latest relaxor-ferroelectric single crystals with engineered-domain structures and very high piezoelectric activity. Additional possibilities of improving the performance of the abovementioned ceramic / polymer composites are concerned with porous structures [1], auxetic polymer components [2, 3] or the addition of a third component, e.g., ferroelectric polymer, ceramic or single crystal with specific electromechanical properties.