Slender structures are ubiquitous in natural and artificial systems across scales, from DNA strands to flagella and space tethers. They also make up a variety of complex systems, from birds’ nests made of twigs to living creatures made of bones, tendons, fibers and muscles.

Cosserat rod theory provides a powerful and versatile framework to model dynamic slender elements, interacting among themselves and the environment. These can be assembled into heterogeneous architectures, active or passive, biological or synthetic, to study their functioning and dynamics at the system level.

Elastica is a free and open-source software project for the simulation of assemblies of slender, one-dimensional bodies using Cosserat rod theory.

What is Cosserat rod theory?

The theory of Cosserat rods is a method of modeling 1D, slender rods accounting for bend, twist, stretch, and shear; allowing all possible modes of deformation to be considered under a wide range of boundary conditions. It models the rod as a deformable curve with attached deformable vectors to characterize its orientation, and evolves the system using a set of coupled second-order, nonlinear partial differential equations.

Elastica is developed by the Gazzola Lab at the University of Illinois at Urbana-Champaign.