DYNAMIC FATIGUE OF CRACKED PIEZOELECTRIC CERAMICS UNDER ELECTROMECHANICAL LOADING: THREE-POINT BENDING TEST AND FINITE ELEMENT ANALYSIS

This paper studies the dynamic fatigue or slow crack growth in piezoelectric ceramics under electromechanical loading by a combined numerical-experimental approach. Constant load-rate testing was conducted in three-point flexure using the single-edge precracked-beam specimens under zero and positive electric fields, and the effects of electric field and loading-rate on the fracture load and crack propagation were examined. A finite element analysis was also employed to calculate the energy release rate for the permeable, impermeable and open crack models, and the effect of electric field on the energy release rate was discussed. Crack propagation velocity versus energy release rate curves at various loading-rate were then estimated based on the finite element analysis using measured data.