The failure probability assessment model of piezoelectric materials under electric fatigue load

The service life of piezoelectric devices is significantly affected by the electric fatigue load. The randomness of loads and nonuniformity of material properties caused by random distribution of internal defects in piezoelectric body will lead to the dispersion of the failure life of piezoelectric devices. Predicting failure probability of piezoelectric materials under electric fatigue load is essential for the reliability and life prediction of piezoelectric structures and devices. In this paper, the initial damage of piezoelectric materials is modeled as a random variable. Based on the methods of probability theory and statistics, the failure probability assessment model of piezoelectric materials under electric fatigue load is proposed. The probability density function of initial damage is obtained by observation and statistics of initial defect area. The failure probability assessment model of piezoelectric materials under electric fatigue load can be obtained by probability theory and integral method. Meanwhile, the failure probability evolution of piezoelectric materials under various electric fatigue loads is considered. The results show that the failure life and dispersion of piezoelectric materials is significantly affected by electric fatigue load, and the variation of failure probability under various electric loads is similar. Based on the proposed failure probability assessment models, the randomness of the electric load and randomly distributed initial defects of materials are considered in the damage evolution and performance prediction of piezoelectric structures, which is an important supplement to the reliability prediction and application of piezoelectric devices.