Dielectric elastomers are soft active materials that deform under voltage and force. Experiments have shown that voltage can cause these materials to strain more than 100%. Due to its fast response time and high energy density, dielectric elastomers have been developed in a wide range of applications, which include artificial muscles, sensors, and power generators.
We formulate theories and develop simulation capabilities to understand the electromechanical response of these materials. Here, we are interested to harness large deformation and instability in these materials to achieve extraordinary functions, such as large deformation, fast speeds, and high energy density. Examples of such efforts include:
Constitutive models for dissipation. Dissipation, such as viscoelasticity and current leakage, undermines performance and plays a key role in any possible application of the technology. We have constructed dissipative models based on non-equilibrium thermodynamics. Performance of dissipative generators has also been analyzed. Similarly, viscoelastic models for dielectric elastomer actuators with solid hydrogel electrodes have also been formulated to explain the cyclic performance of these transducers.
Models to predict large voltage-actuated deformation. Giant deformation for dielectric elastomers is achievable by averting electromechanical instability and other failure modes. Previously we demonstrated large voltage-actuated deformation (areal strain of 488%) for actuators under dead loads in experiments, along with consistent theoretical predictions. In another work led by our collaborators from Princeton University, we presented experiments and simulations to show actuated areal strains over 70% for actuators with stretchable, solid-state electrodes. Such electrodes would be a desirable replacement for the carbon-grease electrodes normally used in lab experiments. In a more recent work, we reported giant deformation for actuators coupled with water.
Stretchable ionics. Dielectric elastomers have also been used in the first demonstration to show that electrical charges carried by ions, rather than electrons, can be put to meaningful use in fast-moving, high-voltage devices.
Modeling soft machines. Other on-going work includes modeling and simulation of various device configurations used in dielectric elastomer actuators and generators. One example is a type of roll actuators, which have been previously developed as generators to harvest energy in ocean waves. Simulation is done using either user-subroutines in commercial FE software or in-house codes.
More details are available in the links below:-