Time-temperature profiles of multi-layer actuators

During accelerated testing of actuators, relatively high frequencies and electric fields are used and the resulting heat generation and self-heating of the actuator due to ferroelectric hysteresis loss becomes of increasing concern. It is therefore important to have knowledge of parameters such as the predicted actuator temperature, total loss per cycle and the overall heat transfer coefficient of the system. The heat generation in multi-layer actuators is studied as a function of driving frequency and applied electric field. The heat transfer coefficients and the total hysteresis loss per cycle in the device are estimated from fitting experimental data to analytical expressions of time-temperature profiles. The temperature rise is found to be approximately proportional to the frequency, while the total loss of the actuator per cycle increases with applied field and frequency. The high estimated values of heat transfer coefficient, which range from 140 to 210Wm-2K-1, are due to the high conductivity and thermal mass of the sample holder. © 2004 Elsevier B.V. All rights reserved.