Many natural and artificial systems can be viewed as made up of soft, slender structures. These structures can be both active and passive. Examples from natural systems are DNA strands, flagella, muscle fibers, and snakes, which illustrates the wide range of length scales these systems span. In artificial systems, examples of such structures are woven cloth, artificial muscles, and long cables.

When the length of such structures is much larger than the radius (L/r » 1), the structure can be viewed as a 1-dimensional rod, allowing substantial simplification of its mathematical treatment. Cosserat rod theory is a mathematical description of such 1-dimensional, slender structures that incorporates the effects of bending, twisting, stretching, and shearing. This allows Cosserat rods to describe the effects of all six degrees of freedom of the rod at each cross-section. These Cosserat rods can be modeled as single rods, or can be combined into assemblies of rods to model more complex systems such as a collection of muscle fibers or the twigs in a bird’s nest.

For more information on Cosserat rods see:

**Theory** – Information on the theory of Cosserat rods.

**Numerics** – Details on the numerical methods we use to solve these systems.

**Multiple Rods** – How to combine multiple rods to create more complex systems.

**Case Studies** – Examples of how Cosserat rods have been used to model different systems.