Modeling of temperature effect on electromechanical properties of dielectric elastomer minimum energy structures

Abstract

Due to the characteristics of large deformation and fast response to excitation voltage, dielectric elastomer minimum energy structures (DEMES) can actively adjust its shape to adapt to the complex environments, which is a research hotspot in the field of soft robotics. The electromechanical properties of DEMES are sensitive to temperature variation. However, the analysis of the effect of temperature on the viscoelastic dynamic behavior of DEMES is incomplete in existing studies. In this paper, an analytical framework for investigating the electromechanical performances of DEMES actuator is presented. By introducing the effects of temperature on the dielectric constant and elastic modulus of DEMES actuator, the governing equations of motion for the underlying non-conservative system affected by temperature are established by combining the DE viscoelastic rheological model and the Euler-Lagrange equation. The proposed model is used for building insights into the effect of temperature on the stiffness, equilibrium state, actuation range and the evolution law of the dynamic response under the DC and AC excitations of DEMES. The results show that a significant enhancement in the equilibrium angle attained by the structure with the improving of the temperature is observed, indicating a favorable impact of ambient temperature. Phase paths and Poincaré maps are presented for assessing the temperature effect on the stability and periodicity of the nonlinear oscillations. The frequency responses of the actuator for the AC loads indicate that a suitable temperature can significantly improve the dynamic performance and stability of DEMES actuator. The proposed analytical model and results presented in this study can provide guidance for the design and development of DEMES based soft robot subjected to harsh environments.