Finite element analysis of thermopiezoelectric bimorph actuators considering temperature-dependent piezoelectric strain coefficients

The application of piezoelectric actuators in smart structures is a rapidly developing field, particularly in aerospace environments. Given the significant impact of thermal effects in aerospace applications, the study of thermopiezoelectricity has gained attention. This phenomenon accounts for the thermal field in addition to the mechanical and electrical fields. Consequently, coupling phenomena among these three fields, including pyroelectric and electrocaloric effects, must be considered. This paper examines how these coupling effects influence the performance of piezoelectric bender actuators in normal operation and under varying external environments. This analysis is conducted through a custom-written finite element code which takes the three fully coupled field equations of thermopiezoelectricity into account. Then, the temperature dependence of the piezoelectric strain coefficients is included into the developed code in a numerically efficient manner using a pre-computation approach. The effect of temperature-dependent material properties is investigated via a case study of a stratospheric balloon flight where the actuator is used as a lens positioning element and subjected to significant temperature variations.