Exploiting Instabilities to Enable Large Shape Transformations in Dielectric Elastomers

Abstract

Dielectric elastomers have significant potential for new technologies ranging from soft robots to biomedical devices, driven by their ability to display complex shape changes in response to electrical stimulus. However, an important shortcoming of current realizations is that large voltages are required for useful actuation strains. This work proposes, and demonstrates through theory and numerical simulations, a strategy to achieve large and controlled actuation by exploiting the electromechanical analog of the Treloar-Kearsley (TK) instability. The key idea is to use the fact that the TK instability is a symmetry-breaking bifurcation, which implies the existence of a symmetry-driven constant-energy region in the energy landscape. This provides for nonlinear soft modes with large deformations that can be accessed with very small external stimulus, which is achieved here by applying a small in-plane electric field. First, the bifurcation and post-bifurcation behavior of the electromechanical TK instability are established theoretically in the idealized setting of uniform deformation and electric field. Next, building on this, a finite element analysis of a realistic geometry with patterned top and bottom electrodes is applied to demonstrate large and soft shape changes driven by small voltage differences across the electrodes.

References in corpus (12)

• DOLFIN: Automated Finite Element Computing
• Flexoelectricity in soft elastomers and the molecular mechanisms underpinning the design and emergence of giant flexoelectricity
• Atomistic-to-Continuum Multiscale Modeling with Long-Range Electrostatic Interactions in Ionic Solids
• The interplay between symmetry-breaking and symmetry-preserving bifurcations in soft dielectric films and the emergence of giant electro-actuation
• Architected Elastomer Networks for Optimal Electromechanical Response
• Statistical Mechanical Analysis of the Electromechanical Coupling in an Electrically-Responsive Polymer Chain
• Nonlinear Statistical Mechanics Drives Intrinsic Electrostriction and Volumetric Torque in Polymer Networks
• Statistical mechanics of a dielectric polymer chain in the force ensemble
• Polymer networks which locally rotate to accommodate stresses, torques, and deformation
• Statistical field theory for nonlinear elasticity of polymer networks with excluded volume interactions
• Statistical Field Theory of Polarizable Polymer Chains with Nonlocal Dipolar Interactions
• Discrete-to-Continuum Limits of Long-Range Electrical Interactions in Nanostructures

Cited by in corpus (2)

• Soft Electromechanical Elastomers Impervious to Instability
• Two-Scale Analysis of the Electrostatics of Dielectric Crystals: Emergence of Polarization Density and Boundary Charges