Thermoelectromechanical Characteristics of Piezoelectric Composites Under Mechanical and Thermal Loading

The electromechanical and thermoelectric responses of piezoelectric composites under mechanical and thermal loading are numerically and experimentally examined. Piezoelectric composites are fabricated using epoxy and BaTiO₃ particles, and three types of single‐layer composites and two types of functionally graded piezocomposites (single‐ and six‐layer composites) are prepared. The resonant frequencies and induced voltages of the composites are measured to determine the influences of mechanical loading and temperature change. Finite element analysis is used to calculate the resonant frequency, stress, and induced voltage due to mechanical loading and temperature change, and the results are compared with the experimental results. Single‐ and six‐layer piezocomposite models are employed in the analysis. By adopting a phenomenological model that considers the temperature dependence of material properties, the effect of the temperature dependence of a physical property on the internal stress and voltage is investigated. It is found that the variations in the temperature‐dependent material constants largely influence the induced voltages of the piezocomposites. In conclusion, functionally graded piezocomposites can be used to control the internal stress and obtain induced voltage from different power sources. It may be useful in designing energy‐harvesting devices for use in vibration‐rich environments and/or environments with severe temperature variations.