High cycle fatigue damage and life time prediction for tetragonal ferroelectrics under electromechanical loading

High cycle fatigue is one of the most crucial problems in designing reliable ferroelectric actuators and sensors. On the micro- and mesoscales, fatigue crack growth determines the life time of the smart ceramic devices, being controlled by both mechanical and electric loads. Giving rise to residual stresses, ferroelectric domain switching and domain wall motion mediate between crack tip and external loading. Thus, two dissipative processes have to be modeled on the microscale, finally leading to evolutions of damage as well as macroscopic piezoelectric, dielectric and stiffness properties. A condensed approach is used to solve the nonlinear constitutive problem of a polycrystalline representative volume and an accumulation model is applied to efficiently handle predictions of high cycle loading. Numerical examples help investigating measures to foster the life time of ferroelectric devices, always keeping an eye on the actuating performance of the system.