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Dynamic analysis of anisotropic dielectric viscoelastomers incorporating humidity effect
ISSN
16785878
Date Issued
2022-08-01
Author(s)
Kumar, Ajay
Khurana, Aman
Sharma, Atul Kumar
Joglekar, M. M.
DOI
10.1007/s40430-022-03646-0
Abstract
Dielectric elastomers are among the soft active materials that may achieve substantial actuation strains when subjected to a high electric field. The material behavior of such elastomers is greatly influenced by environmental humidity. In this paper, we extend upon our previous dynamic modeling frameworks (Khurana et al. in Nonlinear Dyn 104(2):1227–1251, 2021, Sharma and Joglekar in Comput Methods Appl Mech Eng 344:402–420, 2019) to incorporate the effect of humidity in the material model and investigate its effect on the dynamic electromechanical behavior of a transversely isotropic dielectric viscoelastomer actuator with entangled polymer chains. The governing dynamic equation is developed using the non-conservative Euler–Lagrange equation. The proposed model is used for building insights into the effect of membrane humidity on the dynamic behavior and pull-in instability phenomena of the viscoelastomer actuator over a feasible range of anisotropy and entanglement parameters. The results indicate that dielectric elastomer actuators with higher humidity levels have a higher level of deformation and lower electric field at the pull-in point in the DC dynamic mode of actuation, indicating a favorable impact of material humidity. The reduction of critical electric field due to humidity changes can be minimized by integrating the material anisotropy as per the tropical humidity condition. In addition, the Poincaré maps and phase portraits are also plotted to assess the stability, periodicity of the response as well as resonant behavior of the actuator. It is inferred that the higher humidity level of entangled polymer chains diminishes the resonance excitation frequency, which can be further tuned by incorporating material anisotropy. In general, the current study provides initial steps toward the modern actuator designs taking into account the combined effect of humidity conditions, entanglement, and the anisotropic nature of the membrane, which can be effectively implemented for various futuristic applications in the engineering and medical field.