Structure Varying Contact Problems with Friction

2 Structure Varying Contact Problems with Friction 

In this section we consider contact problems, where contact may occur or disappear. In each contact point we assume friction due to Coulomb s law as discussed in the last section. Due to these phenomena the number of degrees of freedom varies with time. First, we discuss the equations of motion for these problems and then consider the question how to decide which of the contacts is active and if in the point of contact stiction or sliding is present. 

In Sec. 5.5 we showed how the equations of motion for contact problems can be derived. In this section we describe structure variant systems based on the work of [GP92]. 

The distance pN must be greater or equal to zero and is given by 

Note that d and n depend on the actual state of the system described by the coordinates p. 

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