Friction Models

Model a block on a moving conveyor belt anchored to a wall by a spring, using different models for the friction force . Compare positions and velocities for the different models. This model incorporates four types of friction: viscous, Coulomb, Stribeck, and static.

Viscous friction is proportional to the relative velocity :

The block quickly settles in a stable position:

Coulomb friction is proportional to the sign of relative velocity :

With the addition of Coulomb friction, the block initially sticks to the belt before settling down:

Stribeck friction is a refined Coulomb friction F_strγ sgn(v) e^-2 :

The relative effect of Stribeck friction in the model is small:

Static friction holds the block in place until the spring force exceeds some value , depending on the roughness of the surfaces:

The block repeatedly sticks to the belt due to frictional forces and then slips back due to the spring force:

Compare the successively refined friction models: