Multidomain Electromechanical Finite Element Modeling of Biomimetic Muscle-Driven Robots Undergoing Large Deformation

Modeling a muscle-driven soft robot requires a description of how active fibers deform the surrounding passive material. We use the existing svFSI solver to study this interaction in SR-EL, an idealized ephyra-inspired bilayer. A neo-Hookean support is coupled to a cardiac-inspired layer described by a modified Holzapfel–Ogden model. An offline Aliev–Panfilov-based calculation supplies the active-stress history; the structural solution does not feed back into activation. The solver uses an established Gibbs-free-energy formulation with variational multiscale stabilization for nearly incompressible response. Compared with our conference paper, this article adds the explicit domain-specific constitutive relations and stabilized finite element formulation, together with the details needed to configure the robotic model. Three time steps and two TET10 meshes are compared over the first 0.1 s. The two-mesh peak-displacement difference is 1.32%, while the final-time common-node displacement-field difference is 6.37%. The example shows how material regions and fiber directions can be combined in a three-dimensional robot model. Its use for predictive design still requires material calibration and independent validation.