A constraint-based collision model for Cosserat rods

The present paper provides a collision model for Cosserat rods, able to represent a very general collision response, including frictional effects as well as multiple simultaneous collisions of a large number of rods. The proposed collision model falls into the category of constraint-based collision models. This concept is extended to a general class of objects sharing properties of rigid and deformable bodies, here undertaken for viscoelastic Cosserat rods. The collision constraints are imposed by collision impulses added to the external loads of the equations of motion of the colliding objects. No iterations between the equations of motion and the collision model are required. Both parts are executed in a staggered manner, so that the collision model is well separated from the equations of motion. Hence, existing solvers for Cosserat rods or similar objects can easily be extended, so that the range of application is significantly enlarged to the collisional regime. Extensive validations are presented using various test cases, ranging from a collision of a single rod with a wall to more realistic configurations with multiple simultaneous collisions of numerous rods.