Impact of electrostriction under unequal biaxial deformation on the nonlinear dynamics of dielectric elastomer actuators

Deformation in dielectric elastomers (DEs) induces electrostriction, significantly impacting their electromechanical properties and actuation performance. Three distinct materials – VHB 4910, Ecoflex 0030, and Oppoband 8001 for DEAs are analyzed under pre-strain conditions ranging from <i>λ_i</i> = 1–4 and <i>λ_j</i> = 2–5, where <i>λ_i</i> ≠ <i>λ_j</i>, to capture a broad range of electromechanical responses associated with varying stiffness and permittivity. Static analysis reveals an anisotropic stress distribution throughout the regimes of pre-strain, highlighting material-dependent responses. VHB 4910 shows the highest stress values, compared to Ecoflex 0030 and Oppoband 8001. Whereas, dynamic analysis under constant electrical and mechanical loading reveals an inverse relationship between deformation and frequency – amplitude and stretch rate increase with deformation, while frequency decreases, indicating reduced stiffness. Lower deformation enhances stability and energy dissipation through higher frequencies and reduced amplitudes. root mean square error (RMSE) analysis from both static and dynamic analysis indicates that models using polarization-based and linear relationships between permittivity and stretch predict stress more accurately than those using a logarithmic relationship. These findings highlight the interplay between electrostriction and deformation, offering insights into optimizing DE actuators (DEAs) for applications requiring precise dynamic responses, such as soft robotics and energy harvesting.