The need to be able to predict the self induced thermal heat rise of piezoelectric and electrostrictive stack actuators under AC dynamic operation motivated the research presented in this paper. First, an equation for the electrical admittance of an stack actuator that explicitly includes the effects of having the stack actuator in a host structure is provided. This equation is then shown to be critical when determining the apparent, reactive and dissipative power used by an actuator. With the theoretical predictions of the electrical admittance available, it is possible to calculate the contributions of the individual loss components to the total dissipative power. Using a simple heat transfer analysis, the internal heat rise of the actuator is predicted given the dissipative power input. A case study is used to illustrate how to apply the developed theories. This research provides a first step toward the ability to predict the temperature state of active materials in stack configurations. This would allow accurate prediction of actuator parameters and hence electro-dynamic behavior. Additionally, knowledge of the physics behind self induced heat rise can be used to avoid exceeding the active materials Curie temperature during operation and allow proper design of active isolation elements for temperature sensitive equipment.
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