Microcracking in piezoelectrics weakens the electromechanical coupling andchanges its directionality

Microcracking in piezoelectrics is found to produce two major effects on th e effective piezoelectric properties: it weakens the electromechanical coup ling and it changes its "directionality", i.e. the direction of mechanical (electrical)response to the applied electrical (mechanical) loads. The latt er effect implies that microcracking in piezoelectric sensors and actuators reduces the accuracy of the devices. We quantify the mentioned loss of acc uracy. This can also be viewed as a quantification of the "piezoelectric fa tigue".