Strain energy density of VO2-based microactuators

The strain, stress and strain energy density of a vanadium dioxide (VO2)-based microactuator were obtained from experimental curvature measurements as a function of temperature. The study revealed fully reversible strain and stress changes of up to -0.32% and -510 MPa, respectively, and a maximum strain energy density of approximately 8.1 x 10(5) J/m(3) through a temperature window of only 15 degrees C. The method for obtaining the strain energy density in this work is more accurate than the ones presented previously in the literature. The obtained values were validated with a temperature-dependent solid mechanics finite element analysis simulation. Microactuator performance was also studied inside its hysteretic region through a series of heating and cooling cycles, providing a more complete performance analysis of the device properties. (c) 2013 Elsevier B.V. All rights reserved.