Low-cycle electro-mechanical fatigue of dielectric elastomers: Pure-shear experiments and life-prediction model

Dielectric elastomers (DEs) often suffer from fatigue failure during electro-mechanical cyclic loading, which significantly constrains the applications of DE-based devices. In this work, we first carried out a series of electromechanical fatigue tests, where the pure-shear DE specimen was loaded with a constant voltage and cyclic stress with various stress levels. It was found that the DE under large cyclic deformation is vulnerable to the low-cycle fatigue in the failure mode of electric breakdown, and the fatigue life is significantly affected by the applied stress amplitudes and mean stresses. An electro-mechanical fatigue failure model was then developed to predict the low-cycle electro-mechanical fatigue life of DEs in a pure-shear cyclic loading mode by using a configurational stress-based damage predictor and an electro-mechanically coupled constitutive model. This work is expected to help guide the safe design and evaluation of DE-based devices.