RELIABILITY OF PIEZOELECTRIC MULTILAYER ACTUA- TORS

The reliability of piezoceramic multilayer actuators is an important issue for the extension of their use. Two completely different load cases have to be distinguished when reliability parameters of these actuators are specified. One is the AC-driving were the actuators have to generate extreme accelerations. The other one is the pure DC-load which is typical for applications which are taking advantage of the ultrahigh resolution of closed loop piezoelectric positioning systems. This paper explains DC- and AC-degradation mechanisms as well as the unique design of the PICMA co-fired actuators which is properly adapted to both load cases. Besides some characteristics of the actuators results of DC- and AC-reliability investigations are presented.