Strain-Rate-Dependent Charge Release and Nonlinear Depolarization in PZT-5H Under Compressive Loading: Modeling and Experimental Validation

The release of bound charge in ferroelectric ceramics under stress is a critical process for pulse power and sensing applications. This work investigates the nonlinear depolarization behavior and charge release characteristics of PZT-5H under low-strain-rate compressive loading (0.0004 s-1to 0.38 s-1). Experimental results reveal that the force-electric response is characterized by a transient voltage pulse, which escalates during loading and decays prior to macroscopic fracture, irrespective of continued stress application. The peak output voltage and the extent of depolarization exhibit strong strain-rate dependence. We identify a critical intrinsic strain threshold of 9% for PZT-5H, beyond which domain switching saturates and the voltage peaks. A mechanistic model for stress-mediated ferroelastic domain switching (90°, 70°, 109°) is proposed to explain the observed nonlinearity. Furthermore, a constitutive energy release model is developed to accurately predict the total discharged charge as a function of strain rate and load, validated against experimental data with high fidelity (R2 > 0.97). This model provides a robust predictive framework for designing and optimizing ferroelectric-based energy discharge devices.