Reliability Studies on Electrostrictive Actuators

Multilayer electrostrictive actuators have numerous applications. Frequently these applications involve harsh mechanical and electrical loads. Furthermore, it is typically expected that these loads be incurred for > 10 8 repetitions (ideally for an infinite number of cycles). This paper describes the electrical and electro-mechanical analyses used at AVX Corporation to assess the performance characteristics of multilayer ceramic actuators, and addresses the effects of electro mechanical cycling on selected device properties. In this study, lead magnesium niobate based multilayer electrostrictive actuators were subjected to a.c. fields at rated device voltage. Capacitance, dissipation factor, displacement vs. voltage, displace ment hysteresis, electro-mechanical quality factor, and resonant frequency were monitored as a function of electro-mechanical cycling. The actuators exhibited highly stable displacements through out the investigation. Changes observed in other properties indicate a possibility of using them as NDE techniques to assess the actuator reliability.