Nonlinear dynamics of an artificial muscle with elastomer–electrode inertia: Modelling and analysis*

Artificial muscles are dielectric elastomers that mimic the response of the natural muscle and are helpful in bio-mimicking applications. The existing literatures are based on the assumption that electrodes are compliant and are focused on materials with greater extensibility than biological matter. This work presents the behaviour of dielectric elastomers considering the elastomer–electrode. The distinguishing point of the proposed work is the appearance of terms related to the elastomer–electrode inertia effect in the governing equation. Equilibrium stretch variation with parameter exhibits cusp catastrophe and is examined. The basin of attraction illustrates the sensitiveness of system dynamics on the initial state and damping. Multi-frequency response exists and its variation with geometry and inertia is presented. The chaotic behaviour is illustrated through the bifurcation diagram, strange attractor and positive Lyapunov exponent. The inertia effect significantly changes the dynamic characteristic from chaotic to non-chaotic or vice-versa. Our results show that electrode inertia significantly impacts the elastomer. The proposed work gives a foundation for precisely designing artificial muscle for practical applications like soft robotics, artificial arms, and different prosthetic implants.