Dielectric and piezoelectric performance of soft PZT piezoceramics under simultaneous alternating electromechanical loading

This study is focused on the investigation of the fundamental properties of piezoceramics under loading conditions simulating the in-service environment of high-strain actuators. High electric field induced polarization and strain responses were experimentally evaluated for a commercial soft PZT material subjected to cyclic mechanical load with different mean stresses and amplitudes. When the stress is applied in-phase with electrical loading, the polarization and strain outputs are found to monotonically decrease with an increase in stress amplitude, until mechanical loading completely impedes the piezoelectric response. An inverse effect occurs for the out-of-phase electromechanical loading tests, in which the polarization and strain outputs increase with increasing stress amplitude. In general, the enhanced polarization and strain responses are accompanied by an unfavorable increased hysteresis and nonlinearity. An attempt has been made to explain the experimental findings by simultaneously taking into account the effects of elastic deformation, domain reorientation, and piezoeffects.