For use in the finite element analysis it was decided that expressing this relationship in terms of stresses would make modelling possible. Due to the viscoelastic properties of polymers, when a polymer is in contact with another surface for a period of time, the asperities start to creep under the normal load. This increases the actual area of contact, thereby increasing the frictional limit. 3.2.2.1 Summation of friction components. An alternative view of friction is put forward by Kragelsky et al.
Mechanical interaction takes place in layers with a thickness of a few tenths of a micron.
As these processes occur at different levels they are largely uncorrelated and hence can be separated. 3.2.2.2 Effect of spin finish on friction. This prevents them being snagged by the guides and thus being broken or drawn out of the yarn. The yarns used in the tests referred to in this chapter are from spools used to make Parafil ropes and so carry the finishes present in actual ropes. 3.2.1 Classical friction.