Analysis of mechanical systems driven by electrostrictive actuators

A dynamics model of an electrostrictive ceramic actuator is integrated with a linear mechanical system. Electrostrictive ceramics have a non-linear displacement response to applied field, which creates harmonic distortion of actuator's output. Traditionally, nonlinear dynamics problems are solved in the time-domain, then Fast Fourier Transforms are used to convert the solution into the more convenient frequency-domain. In this paper, a new approach is introduced separates the nonlinear, actuator from the linear structure. The structure can be represented as an impedance that constrains the actuator, and the actuator problem is solved in the frequency domain directly. The approach significantly simplifies the nonlinear problem. The actuator-mechanical system model is used to predict actuator output and distortion as a function of signal frequency. DC voltage bias is treated as a model parameter than must be tuned to optimized output while minimizing distortion. Power requirements and energy transfer to the attached structure are also examined. The problem of a flextensional underwater sonar transducer with an electrostrictive driver is examined as an example case.