Modelling of Electromechanical Coupling in Geometrically Exact Beam Dynamics

Abstract

Dielectric elastomers show promising performance as actuators for soft robotics. Thus, accurate and efficient numerical algorithms for the simulation of Dielectric Elastomer Actuators (DEAs) are required for the design and control of the soft robotic system. In this work, the Cosserat formulation of geometrically exact beam dynamics is extended by adding the electric potential as an additional degree of freedom to account for the electrical effects. A formulation of electric potential and electric field for the geometrically exact beam model is proposed such that complex beam deformations can be generated by the electrical forces. The kinematic variables in continuum electromechanics are formulated in terms of beam strains. The electromechanically coupled constitutive model for the beam formulation is obtained by integrating the strain energy in continuum electromechanics over the beam cross section, which leads to a direct transfer of the dielectric constitutive models in continuum mechanics to the beam model. The electromechanically coupled beam dynamics is solved with a variational time integrator scheme. By applying different electrical boundary conditions to the beam nodes, different deformation modes of the beam are obtained in the numerical example.