Fatigue Behavior of Cracked Piezoelectric Ceramics in Cyclic Three-Point Bending under AC Electric Fields

Abstract

This paper investigates analytically and experimentally the cyclic fatigue behavior in piezoelectric ceramics with a crack normal to the poling under alternating current (AC) electric fields. Fatigue tests were performed in three-point bending with the single-edge precracked-beam (SEPB) specimens, and numbers of cycles to failure under sinusoidal mechanical loads and AC electric fields were obtained. Finite element analysis was also conducted using a phenomenological model of domain wall motion, and the energy release rate was calculated. The effect of AC electric fields on the maximum energy release rate versus number of cycles to failure curve was then discussed. In addition, the fracture surfaces were examined by scanning electron microscopy to correlate with fatigue characteristics. The important conclusions are that when the AC electric fields with the same phase of the sinusoidal mechanical loads are applied to the cracked piezoelectric ceramics, the number of cycles to failure becomes smaller and the slope of the maximum energy release rate versus number of cycles to failure becomes steeper.