Modelling and characterization of dielectric elastomer stack actuators

This paper aims to establish and evaluate an electrical and mechanical model for dielectric elastomer stack actuators. Based on the structure of an electrically interconnected actuator a simplified electrical and mechanical network is deduced.The electrical model results in a low-pass filter. The model is evaluated by measurements of the electrical impedance and contact, electrode and parallel resistances. Measurement results show good agreement of the model with the electrical behaviour of the real actuator over a wide frequency range, from below 0.1 Hz to above 10 kHz.The mechanical modelling is split into dynamic and static behaviour. The dynamic mechanical behaviour is modelled as a mechanical equivalent network using fractional elements. The static mechanical model uses the uniaxial compressive modulus of the actuator material to describe the static characteristic.The combination of static and dynamic models allows a realistic prediction of the static and dynamic deflection of the actuators under an applied electrical voltage. This electro-mechanical model has been validated in a frequency range of 4 Hz to 4 kHz.